T^/3 f t irinity College Library Durham, N. C. Rec’d Tun) 2 j. J f 2- 3 } Digitized by the Internet Archive in 2016 with funding from Duke University Libraries https://archive.org/details/practicaltreatis01fann PUBLIC FOUNTAIN, CINCINNATL A PRACTICAL TREATISE ON HYDRAULIC AND Water-Supply Engineering: RELATING TO THE HYDROLOGY, HYDRODYNAMICS, AND PRACTICAL CONSTRUCTION OF WATER-WORKS, IN NORTH AMERICA. WITH NUMEROUS TABLES AND ILLUSTRATIONS, J. T. FANNING, C. E., MEMBER OF THE AMERICAN SOCIETY OF CIVIL ENGINEERS; FELLOW OF THE AMERICAS ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE ; MEMBER OF THE AMERICAN PUBLIC HEALTH ASSOCIATION; MEMBER OF THE NEW ENGLAND WATER WORKS ASSOCIATION ; PAST PRESIDENT OF THE AMERICAN WATER WORKS ASSOCIATION. EIGHTEENTH EDITION, REVISED, ENLARGED. AND NEW TABLES AND ILLUSTRATIONS ADDED. NEW YORK D. VAN NOSTEAND COMPANY 25 Park Place 1913 C Qj ' ^7 3 ^ ^ t^v wt* titc Copyright, 1877. 188G, 1890, 1901, 1906, BY J. T. FANNING. PUMPING STATION, CHESTNUT HILL, BOSTON, Page iii. Co ^ ^ PREFACE. HEEE is at present no sanitary subject of more general interest, or attracting more general attention, than that relating to the abundance and wholesomeness of domestic water Each citizen of a densely populated municipality must of necessity be personally interested in either its physiological or its financial bearing, or in both. Each closely settled town and city must give the subject earnest consideration early in its ex- istence. At the close of the year 1875, fifty of the chief cities of the American Union had provided themselves with public water sup- plies at an aggregate cost of hot less than ninety-five million dollars, and two hundred and fifty lesser cities and towns were also provided with liberal public water supplies at an aggregate cost of not less than fifty-five million dollars. The amount of capital annually invested in newly inaugurated water-works is already a large sum, and is increasing, yet the entire American literature relating to water-supply engineering exists, as yet, almost wholly in reports upon individual works, usually in pamphlet form, and accessible each to but compara- tively few of those especially interested in the subject. Scores of municipal water commissions receive appointment each year in the growing young cities of the Union, who have to inform themselves, and pass judgment upon, sources and systems supplies. vi PREFACE. of water supply, which are to become helpful or burdensome to the communities they are intended to encourage accordingly as the works prove successful or partially failures. The individual members of these “Boards of Water Commis- sioners,” resident in towns where water supplies upon an extended scale are not in operation, have rarely had opportunity to observe and become familiar with the varied practical details and appa- ratus of a water supply, or to acquaint themselves with even the elementary principles governing the design of the several different systems of supply, or reasons why one system is most advanta- geous under one set of local circumstances and another system is superior and preferable under other circumstances. A numerous band of engineering students are graduated each year and enter the field, many of whom choose the specialty of hydraulics, and soon discover that their chosen science is great among the most noble of the sciences, and that its mastery, ir theory and practice, is a work of many years of studious acquire- ment and labor. They discover also that the accessible literature of their profession, in the English language, is intended for the class-room rather than the field, and that its formulae are based chiefly upon very limited philosophical experiments of a century and more ago hut partially applicable to the extended range of modern practice. Among the objects of the author in the compilation of the following pioneer treatise upon American Water- works are, to supply water-commissionei’s with a general review of the best methods practised in supplying towns and cities with water, and with facts and suggestions that will enable them to compare in- telligently the merits and objectionable features of the different potable water sources within their reach ; to present to junior and assistant hydraulic engineers a condensed summary of those ele- mentary theoretical principles and the involved formulas adapted to modern practice, which they will have frequently to apply, together with some useful practical observations ; to construct and gather, for the convenience of the older busy practitioners, PREFACE. vii numerous tables and statistics that will facilitate their calcula- tions, some of which would otherwise cost them, in the midst of pressing labors, as they did the author, a great deal of laborious research among rare and not easily procurable scientific treatises ; and also to present to civil engineers generally a concise reference manual, relating to the hydrology, hydrodynamics, and practical construction of the water-supply branch of their profession. This work is intended more especially for those who have already had a task assigned them, and who, as commissioner, engineer, or assistant, are to proceed at once upon their recon- noissance and surveys, and the preparation of plans for a public water supply. To them it is humbly submitted, with the hope that it will prove in some degree useful. Its aim is to develop the bases and principles of construction, rather than to trace the origin of, or to describe individual works. It is, therefore, prac- tical in text, illustration, and arrangement ; but it is hoped that the earnest, active young workers will find it in sympathy with their mood, and a practical introduction, as well, to more pro- found and elegant treatises that unfold the highest delights of the science. Good design, which is invariably founded upon sound mathe- matical and mechanical theory, is a first requisite for good and judicious practical engineering construction. We present, there- fore, the formulae, many of them new, which theory and practical experiments suggest as aids to preliminary studies for designs, and many tables based upon the formulas, which will facilitate the labors of the designer, and be useful as checks against his own com- putations, and we give in addition such discussions of the elemen- tary principles upon which the theories are founded as will enable the student to trace the origin of each formula ; for a formula is often a treacherous guide unless each of its factors and experience coefficients are well understood. To this end, the theoretical dis- cussions are in familiar language, and the formulas in simple ar- rangement, so that a knowledge of elementary mathematics only is necessary to read and use them. PREFACE. viii We do by no means intimate, however, that an acquaintance with elementary theories alone suffices for an accomplished en- gineer. It is sometimes said that genius spurns rules, and it is true that untutored genius sometimes grapples with and accom- plishes great and worthy deeds, but too often in a bungling manner, not to be imitated. In kindly spirit we urge the student to bear in mind that it is the rigorously trained genius who oftenest achieves mighty works by methods at once accurate, economical, artistic, and in every respect succeessful and admirable. J. T. F. Boston, November, 1876. PREFACE TO THE FIFTEENTH EDITION. A T the time of issue of the first edition of this book there were 1 only about 300 American cities and towns having public water supplies. On issue of this fifteenth edition there are about 5000 complete public water supplies in North America, that have cost in the aggregate many hundred millions of dollars. The first preface stated that this book was intended to aid commissioners and engineers who were to proceed at once with plans and constructions of water supplies. That the book found a practical mission and influenced the designs and constructions of many public water supplies is evidenced by the generous domestic and foreign purchases of the work. This evidence of practical use- fulness is most gratifying and the kind reception of the book in the class-room, the office and the field is highly appreciated by the author. To each successive edition have been added useful new tables, text and illustrations, so that the book might, so far as possible in a general treatise, keep in progress with advances in the art of hydraulic engineering. J. T. F. Minneapolis, Minn., September, 1901. P. viii/? WATER TOWER, ST. LOUIS, W. W. TANK STAND-PIPE, FREMONT, O. IX CONTENTS SECTION I. COLLECTION AND STORAGE OF WATER, AND ITS IMPURITIES. CHAPTER I. INTRODUCTORY.— Page 25. Art. 1, Necessity of Public Water Supplies. — 2, Physiological Office of Water. — 3, Sanitary Office of Water Supplies. — 4, Helpful Influence of Public Water Supplies. — 5, Municipal Control of Public Water Supplies. — 6, Value as an Investment. — 7, Incidental Advantages. CHAPTER II. QUANTITY OF WATER REQUIRED.— Page 31. Art. 8, Statistics of Water Supplied.— 9, Census Statistics. — 10, Approximate Consumption of Water. — 11, Water Supplied to Ancient Cities. — 12, Water Supplied to European Cities. — 13, Water Supplied to American Cities. — 14, The Use of Water Steadily Increasing. — 15, Increase in Various Cities. — 16, Relation of Supply per Capita to Total Population. — 17, Monthly and Hourly Variations in the Draught. — 18, Ratio of Monthly Consump tion. — 19, Illustrations of Varying Consumption. — 20, Reserve for Fire Extinguishment. CHAPTER III. RAINFALL.— Page 45. Art. 21, The Vapory Elements of Water. — 22, The Liquid and Gaseous Succes- sions. — 23, The Source of Showers. — 24, General Rainfall. — 25, Review of Rainfall Statistics. — 26, Climatic Effects. — 27, Sections of Maximum Rain- fall. — 28, Western Rain System. — 29, Central Rain System. — 30, Eastern Coast System. — 31, Influence of Elevation upon Precipitation. — 32, River Basin Rains. — 33, Grouped Rainfall Statistics. — 34, Monthly Fluctuations X CONTENTS. in Rainfall. — 35, Secular Fluctuations in Rainfall. — 36, Local Physical and Meteorological Influences. — 37, Uniform Effects of Natural Laws. — 38, Great Rain Storms. — 39, Maximum Ratios of Floods to Rainfalls. — 40, Volume of Waterfrom given Rainfalls. — 41, Gauging Rainfalls. CHAPTER IV. FLOW OF STREAMS.— Page 65. Art. 42, Flood Volumes Inversely as the Areas of Basins. — 43, Formulas for Flood Volumes. — 44, Table of Flood Volumes.— 45, Seasons of Floods. — 46, Influence of Absorption and Evaporation upon Flow. — 47, Flow in Sea- sons of Minimum Rainfall. — 48, Periodic Classification of available Flow. — 49, Sub-surface Equalizers of Flow. — 50, Flashy and Steady Streams. — 51, Peculiar Watersheds. — 52, Summaries of Monthly Flow Statistics. — 53, Minimum, Mean, and Flood Flow of Streams. — 54, Ratios of Monthly Flow in Streams. — 55, Mean Annual Flow of Streams. — 56, Estimates of Flow of Streams. — 57, Ordinary Flow of Streams. — 58, Tables of Flow, Equivalent to given Depths of Rain. CHAPTER V. STORAGE AND EVAPORATION OF WATER.— Page 84. Storage. — Art. 59, Artificial Storage. — 60, Losses Incident to Storage. — 6i, Sub-strata of the Storage Basin. — 62, Percolation from Storage Basins. — 63, Rights of Riparian Owners. — 64, Periodical Classification cf Riparian Rights. — 65, Compensations. — Evaporation. — 66 , Loss from Reservoir by Evaporation. — 67, Evaporation Phenomena.— 68, Evaporation from Water. — 69, Evaporation from Earth. — 70, Examples of Evaporation. — 71, Ratios of Evaporation. — 72, Resultant Effect of Rain and Evaporation. — 73, Practical Effect upon Storage. CHAPTER VI. SUPPLYING CAPACITY OF WATER-SHEDS.— Page 94. Art. 74, Estimate of Available Annual Flow of Streams. — 75, Estimate of Monthly available Storage Required. — 76, Additional Storage Required. — /7, Utilization of Flood Flows. — 78, Qualification of Deduced Ratios. — 79, Influence of Storage upon a Continuous Supply. — 80, Artificial Gathering Areas. — 81, Recapitulation of Rainfall Ratios. CHAPTER VII. SPRINGS AND WELLS.— Page 102. Art. 82, Subterranean Waters. — 83, Their Source, the Atmosphere. — 84. Po- rosity of Earths and Rocks. — S5, Percolations in the Upper Strata. — 86, The Courses cf Percolation. — S7 Deep Percolations.- 88, Subterranean CONTENTS. xi Reservoirs.— 89, The Uncertainties of Subterranean Searches. — 90, Re- nowned Application of Geological Science. — 91, Conditions of Overflow- ing Wells.— 92, Influence of Wells upon each other.— 93, American Ar- tesian Wells. — 94, Watersheds of Wells. — 95, Evaporation from Soils*-. 96, Supplying Capacity of Wells and Springs. CHAPTER VIII. IMPURITIES OF WATER. — Page 112. Art. 97> The Composition of Water. — 98, Solutions in Water. — 99, Properties of Water. — ioo, Physiological Effects of the Impurities of Water. — ioi, Mineral Impurities.— 102, Organic Impurities. — 103, Tables of Analyses of Potable Waters. — 104, Ratios of Standard Gallons. — 105, Atmospheric Impurities. — 106, Sub-surface Impurities. — 107, Deep-well Impurities. — 108, Hardening Impurities. — 109, Temperature of Deep Sub-surface Waters. — no, Decomposing Organic Impurities. — m, Vegetal Organic Impurities. — 112, Vegetal Organisms in Water-pipes. — 113, Animate Or- ganic Impurities. — 114, Propagation of Aquatic Organisms. — 115, Purify- ing Office of Aquatic Life. — 116, Intimate Relation between Grade of Organisms and Quality of Water. — 117, Animate Organisms in Water- pipes. — 118, Abrasion Impurities in Water. — 119, Agricultural Impuri- ties. — 120, Manufacturing Impurities. — 121, Sewage Impurities. — 122, Impure Ice in Drinking-Water. — 123, A Scientific Definition of Polluted Water. CHAPTER IX. WELL, SPRING, LAKE, AND RIVER SUPPLIES.— Page 139. Well Waters. — Art. 124, Locations for Wells. — 125, Fouling of Old Wells.— Spring Waters. — 126, Harmless Impregnations. — 127, Mineral Springs. — Lake Waters. — 128, Favorite Supplies. — 129, Chief Requisites. — 130, Impounding. — 131, Plant Growth. — 132, Strata Conditions. — 133, Plant and Insect Agencies. — 134, Preservation of Purity. — 135, Natural Clarifi- cation. — 136, Great Lakes. — 137, Dead Lakes. — River Waters. — 138, Metropolitan Supplies. — 139, Harmless and Beneficial Impregnations. — 140, Pollutions. — 141, Sanitary Discussions. — 142, Inadmissible Polluting Liquids, — 143, Precautionary Views. — 144, Speculative Condition of the Pollution Question. — 145, Spontaneous Purification. — 146, Artificial Clari- fication. — 147, A Sugar Test of the Quality of Water. xii CONTENTS. SECTION II. FLOW OF WATER THROUGH SLUICES, PIPES, AND CHANNELS. CHAPTER X. WEIGHT, PRESSURE, AND MOTION OF WATER.— Page 161. Art. 148, Special Characteristics ofWater. — 149, Atomic Theory. — 150, Molec- ular Theory. — 151, Influence of Caloric. — 152, Relative Densities and Volumes. — Weight of Water. — 153, Weight of Constituents of Water. — 154, Crystalline Forms of Water. — 155, Formula for Volumes at Differ ent Temperatures. — 156, Weight of Pond Water. — 157, Compressibility and Elasticity ofWater. — 158, Weights of Individual Molecules. — 159, In- dividual Molecular Actions. — Pressure of Water. — 160, Pressure Propor- tional to Depth. — 161, Individual Molecular Reactions.— -162, Equilibrium destroyed by an Orifice. — 163, Pressures from Vertical, Inclined, and Bent Columns of Water. — 164, Artificial Pressure. — 165, Pressi ve upon a Unit of Surface. — 166, Equivalent Forces. — 167, Weight a Measure of Pressure. — 168, A Line a Measure of Weight. — 169, A Line a measure of Pressure upon a Surface. — 170, Diagonal Force of Combined Pressures Graphically Represented. — 171, Angular Resultant of a Force Graphically Repre- sented. — 172, Angular Effects of a Force Represented bjr the Sine and Cosine of the Angle. — 173, Total Pressure. — 174. Direction of Maximum Effect. — 175, Herizontal and Vertical Effects. — 176, Centres of Pressure and of Gravity — 177, Pressure upon a Curved Surface, and Effect upon its Projected Plane. — 178, Centre of Pressure upon a Circular Area.— 179, Combined Pressures. — 180, Sustaining Pressure upon Floating and Submerged Bodies. — 181, Upward Pressure upon a Submerged Lintel. — 182, Atmospheric Pressure.- — 183, Rise of Water into a Vacuum. — 184, Siphon. — 185, Transmission of Pressure to a Distance. — 186, Inverted Syphon. — 187, Pressure Convertible into Motion. — Motion of Water. — 188, Flow of Water. — 189, Action of Gravity upon Individual Molecules. — igo, Frictionless Movement of Molecules. — 191, Acceleration of Motion. —192, Equations of Motion. — 193, Parabolic Path of Jet. — 194, Velocity of Efflux Proportional to the Head. — 195, Conversion of the Force of Grav- ity from Pressure into Motion. — 196, Resultant Effects of Pressure and Gravity upon the Motion of a Jet. — 197, Equal Pressures give Equal Velocities in all Directions. — 198, Resistance of the Air. — 199, Theoretical Velocities. CHAPTER XI. FLOW OF WATER THROUGH ORIFICES.— Page 194. Art. 200, Motion of the Individual Particles. — 201, Theoretical Volume of Efflux. — 202, Converging Path of Particles. — 203, Classes of Orifices.— CONTENTS. yin 204, Form of Submerged Orifice Jet. — 205, Ratio of Minimum Section of Jet. — 206, Volume of Efflux. — 207, Coefficient of Efflux. — 208, Maximum Velocity of the fet. — 209, Factors of the Coefficient of Efflux. — 210, Prac- tical Use of a Coefficient. — 211, Experimental Coefficients. (From Michel- ott 1 ', Abbe Bosset, Rennie, Castel, Lespinasse, General Ellis.) — 212, Co- efficients Diagramed. — 213, Effect of Varying the Head, or the Proportions of the Orifice. — 214, Peculiarities of Efflux from an Orifice.- — 215, Mean Velocity of the Issuing Particles. — 216, Coefficients of Velocity and Contraction. —217. Velocity of Particles Dependent upon their Angular Positions. — 218, Equation of Volume of Efflux from a Submerged Orifice. — 219, Effect of Outline of Geometrical Orifices upon Efflux. — 220, Vari- able Value of Coefficients. — 221, Assumed Mean Value of Efflux. — 222, Circular Jets, Potygonal do.. Complex do. — 223, Cylindrical and Divergent Orifices. — 224, Converging Orifices. CHAPTER XII. FLOW OF WATER THROUGH SHORT TUBES.— Page 213. Art. 225, An Ajutage. — 226, Increase of Coefficient. — 227, Adjutage Vacuum, and its Effect. — 228, Increased Volume of Efflux. — 229, Imperfect Va- cuum. — 230, Divergent Tube. — 231, Convergent Tube. — 232, Additional Contraction. — 233, Coefficients of Convergent Tubes. — 234, Increase and Decrease of Coefficient of Smaller Diameter. — 235, Coefficient of Final Velocity. — 236, Inward Projecting Ajutage. — 237, Compound Tube. — 238, Coefficients of Compound Tubes. — 239, Experiments with Cylindri- cal and Compound Tubes. — 240, Tendenc)' to Vacuum. — 241, Percussive Force of Particles. — 242, Range of Eytelwein’s Table. — 243, Cylindrical Tubes to be Preferred. CHAPTER XIII. FLOW OP WATER THROUGH PIPES, UNDER PRESSURE.— Page 223. Art. 244, Pipe and Conduit.--245, Short Pipes give Greatest Discharge. — 246, Theoretical Volume from Pipes. — 247, Mean Efflux from Pipes. — 248, Sub- division of the Head. — 249, Mechanical Effect of the Efflux. — 250, Ratio of Resistance at Entrance to the Pipe. — Resistance to Flow within A Pipe. — 251, Resistance of Pipe-Wall. — 252, Conversion of Velocity into Pressure. — 253, Coefficients of Efflux from Pipes. — 254, Reactions from the Pipe-Wall. — 255, Origin of Formulas of Flow. — 256, Formula- of Resist- ance to Flow. — 257, Coefficient of Flow. — 258, Opposition of Gravity and Reaction. — 259, Conversion of Pressure into Mechanical Effect. — 260, Measure of Resistance to Flow — 261, Resistance Inversely as the Square of the Velocity. — 262, Increase of Bursting Pressure. — 263, Acceleration and Resistance. — 264, Equation of Head Required to Overcome the Re- sistance. — 265, Designation of h" and l. — 266, Variable Value of in. — 267, Investigation of Values of m. — 268, Definition of Symbols. — 269, Experi- CONTENTS. xiv mental Values of the Coefficient of Floxv. — 270, Peculiarities of the Coeffi- cient (m) of Flow. — 271, Effects of Tubercles. — 272, Classification of Pipes and their Mean Coefficients. — 273, Equation of the Velocity Neutralized by Resistance to Flow. — 274, Equation of Resistance Head.— 275, Equation of Total Head. — 276, Equation of Volume. — 277, Equation of Diameter. — 278, Relative Value of Subdivisions of Total Head. — 279, Many Popular Formulas Incomplete. — 280 — Formula of M. Chezy. — 281, Various Pop- ular Formulas Compared. — 282, Sub-heads Compared. — 283, Investiga- tions by Dubuat, and Coloumb, and Prony. — 284, Prony’s Anal)-sis. — 285, Eytelwein’s Equation of Resistance to Flow. — 286, D’Abuisson’s Equation of Resistance to Flow. — 287, Weisbach’s Equation of Resistance to Flow. — 288, Transpositions of an Original Formula. — 289, Unintelligent Use of Partial Formulas. — 290, A Formula of more General Application. — 291, Values of v for Given Slopes. — 292, Values of h and Ji! for Given Velocities. — 293, Classified Equations for Velocity, Head, Volume, and Diameter. — 294, Coefficients of Entrance of Jet. — 295, Mean Coefficients for Smoothi Rough, and Foul Pipes. — 296, Mean Equations for Smooth, Rough, and Foul Pipes. — 297, Modification of a Fundamental Equation of Velocity. ■ — 298, Values of P. — 299, Bends. — 300, Branches. — 301, How to Economize Head. CHAPTER XIV. MEASURING WEIRS, AND WEIR GAUGING.— Page 277. Art. 302, Gauged Volumes of Flow. — 303, Form of Weir. — 304, Dimensions. — 305, Stability. — 306, Varying Length. — 307, End Contractions. — 308, Crest Contractions. — 309, Theory of Flow over a Weir. — 310, Formulas for Flow, without and with Contractions. — 3 11, Increase of Volume due to Initial Velocity of Water. — 312, Coefficients for Weir Formulas. — 313, Discharges for Given Depths. — 314, Vacuum under the Crest. — 315, Ex- amples of Initial Velocity. — 316, Wide-crested Weirs. — 317, Triangular- Notch Weirs. — 318, Obstacles to Accurate Measures. — 319, Hook Gauge. —320, Rule Gauge. — 321, Tube and Scale Gauge. CHAPTER XV. FLOW OF WATER IN OPEN CHANNELS.— Page 299. Art. 322, Gravity the Origin of Flow. — 323, Resistance to Flow. — 324, Equa- tions of Resistance and Velocity. — 325, Equation of Inclination. — 326, Co- efficients of Flow for Channels. — 327, Observed Data of Flow in Channels. — 328, Table of Coefficients for Channels. — 329, Various Formulas of Flow Compared. — 330, Velocities of Given Films. — 331, Surface Velocities. — 332, Ratios of Surface to Mean Velocities. — 333, Hydrometer Gaugings. — 334, Tube Gauges — 335, Gauge Formulas. — 336, Pitot Tube Gauge — 337, Woltmann’s Tachometer. — 338, Hydrometer Coefficients. — 339. Henry's Telegraphic Mouiinet. — 340, Earlier Hydrometers. — 341, Double Floats. — 342, Mid-depth Floats. — 343, Maximum Velocity Floats. — 344, Relative Velocities and Volumes due to Different Depths. CONTENTS. XY SECTION III. PRACTICAL CONSTRUCTION OF WATER-WORKS. CHAPTER XVI. RESERVOIR EMBANKMENTS AND CHAMBERS.— Page 333. Art. 345, Ultimate Economy of Skillful Construction. — 346, Embankment Foun- dations. — 347, Springs under Foundations. — 348, Surface Soils. — 349, Con- crete Cut-off Walls. — 350, Treacherous Strata. — 351, Embankment Core Materials. — 352, Peculiar Pressures. — 353, Earthwork Slopes. — 354, Re- connaissance for Site.— 355, Detailed Surveys. — 356, Illustrative Case. — 357, Cut-off Wall. — 358, Embankment Core. — 359, Frost Covering. — 360, Slope Paving. — 361, Puddle Wall. — 362, Rubble Priming Wall. — 363, A Light Embankment.— 364, Distribution Reservoirs. — 365, Application of Fine Sand. — 366, Masonry — Faced Embankment. — 367, Concrete Paving. 368, Embankment Sluices and Pipes. — 369, Gate Chambers. — 370, Sluice Valve Areas. — 371, Stop-valve Indicator. — 372, Power required to Open a Valve, — 373, Adjustable Effluent Pipe. — 374, Fish Screens. — 375, Gate Chamber Foundations. — 376, Foundation Concrete. — 377, Chamber Walls. CHAPTER XVII. OPEN CANALS. — Page 370. Art. 378, Canal Banks. — 379, Inclinations and Velocities in Practice. — 380, Ice Covering. — 381, Table of Dimensions of Supply Canals. — 382, Canal Gates. — 383, Miners’ Canals. CHAPTER XVII I. WASTE WEIRS.— Page 377. Art. 384, The Office and Influence of a Waste-Weir. — 385, Discharges over Waste-Weirs. — 386, Required Lengths of Waste- Weirs. — 387. Forms of Waste-Weirs. — 388. Isolated Weirs. — 389, Timber Weirs. — 390, Ice-Thrust upon Storage Reservoir Weirs. — 391, Breadths of Weir-Caps. — 392, Thick- nesses of Waste-Weirs and Dams. — 393, Force of Overflowing Water.^ 394, Heights of Waves. CHAPTER XIX. PARTITIONS AND RETAINING WALLS.— Page 390. Art. 395, Design. — 396, Theory of Water-Pressure upon a Vertical Surface. — 397, Water Pressure upon an Inclined Surface.— 398, Frictional Stability CONTENTS. xvi of Masonry. — 399, Coefficients of Masonry Friction. — 400, Pressure Lever- age of Water.— 401, Leverage Stability of Masonry. — 402, Moment of Weight Leverage of Masonry. — 403, Thickness of a Vertical Rectangular Wall for Water Pressure. — 404, Moments of Rectangular and Trapedoidal Sections. — 405, Graphical Method of Finding the Leverage Resistance. — 406, Granular Stability. — 407, Limiting Pressures. — 408, Table of Walls for Quiet Water. — 409, Economic Profiles. — 410, Theory of Earth Pressures. — 41 1, Equation of Weight of Earth Wedge. — 412, Equation of Pressure of Earth Wedge. — 413, Equation of Moment of Pressure Leverage. — 414, Thickness of a Vertical Rectangular Wall for Earth Pressure. — 415, Sur- charged Earth Wedge. — 416, Pressure of a Surcharged Earth "Wedge. — 417, Moment of a Surcharged Pressure Leverage. — 418, Pressure of an Infinite Surcharge. — 419, Resistance of Masonry Revetments. — 420, Final Resultants in Revetments. — 421. Table of Trapezoidal Revetments. — 422, Curved-face Batter Equation. — 423, Back Batters and their Equations. — 424, Inclination of Foundation. — 425, Front Batters and Steps. — 426, Top Breadth. — 427, Wharf Walls. — 428, Counterforted Walls. — 429, Ele- ments of Failure. — 430, End Supports. — 431, Faced and Concrete Revet- ments. CHAPTER XX. MASONRY CONDUITS.— Page 431. Art. 432, Protection of Channels for Domestic Water Supplies. — 433, Examples of Conduits. — 434, Foundations of Conduits. — 435, Conduit Shells. — 436, Ventilation of Conduits. — 437, Conduits under Pressure. — 438, Protection from Frost. — 439, Masonry to be Self-sustaining. — 440, A Concrete Con- duit. — 441, Example of a Conduit under Heavy Pressure. — 442, Mean Radii of Conduits. — 443, Formulas of Flow for Conduits. — 444, Table of Conduit Data. CHAPTER XXI. MAINS AND DISTRIBUTION PIPES— Page 446. Art. 445, Static Pressures in Pipes. — 446, Thickness of Shell resisting Static Pressure. — 447, Water-Ram. — 448, Formulas of Thickness for Ductile Pipes. — 449, Strengths of Wrought Pipe Metals. — 450, Moulding of Pipes. — 451, Casting of Pipes. — 452, Formulas of Thickness for Cast-iron Pipes. 453, Thicknesses found Graphically. — 454, Table of Thicknesses of Cast- iron Pipes. — 455, Table of Equivalent Fractional Expressions. — 456, Cast- iron Pipe-Joints. — 457, Dimensions of Pipe-Joints. — 45S, Templets for Bolt Holes. — 459, Flexible Pipe-Joint. — 460, Thickness Formulas Com- pared. — 461, Formulas for Weights of Cast-iron Pipes. — 462, Table of Weights of Cast-iron Pipes. — 463, Interchangeable Joints. — 464, Charac- teristics of Pipe Metals. — 465, Tests of Pipe-Metals. — 466, The Preserva- tion of Pipe Surfaces. — 467, Varnishes for Pipes and Iron "Work. — 468, Hydraulic Proof of Pipes. — 469, Special Pipes.— 470, Cement-lined and CONTENTS. svii Coated Pipes. — 471, Methods of Lining. — 472, Covering. — 473, Cement Joints. — 474, Cast Hub Joint. — 475, CQmposite Branches. — 476, Thickness of Shells for Cement Linings. — 477, Gauge Thickness and Weights of Rolled Iron. — 478, Lining, Covering, and Joint Mortar. — 479, Asphaltum- Coated Wrought-iron Pipes. — 480, Asphaltum Bath, for Pipes. — 481, Wrought Pipe Plates. — 482, Bored Pipes. — 483, Wyckoff’s Patent Pipe. CHAPTER XXII. DISTRIBUTION SYSTEMS, AND APPENDAGES.— Page 493. Art. 484, Loss of Head by Friction — 485, Table of Frictional Heads in Pipes. — 486, Relative Discharging Capacities of Pipes. — 487, Table of Relative Capacities of Pipes. — 488, Depths of Pipes. — 489, Elementary Dimensions of Pipes.— 490, Distribution Systems. — 491, Rates of Consumption of Water. — 492, Rates of Fire Supplies. — 493, Diameter of Supply Main. — 494, Diameters of Sub-mains. — 495, Maximum Velocities of Flow. — 496, Comparative Frictions. — 497, Relative Rates of Flow for Domestic and Fire Supplies. — 498, Required Diameters for Fire Supplies. — 499, Duplica- tion Arrangement of Sub Mains. — 500, Stop-Valve Systems. — 501, Stop- Valve Locations. — 502, Blow-off and Waste Valves. — 503, Stop-Valve De- tails. — 504, Valve Curbs. — 505, Fire Hydrants. — 506, Post Hydrants. — 507, Hydrant Details. — 508, Flush Hydrants. — 509, Gate Hydrants. — 510, High Pressures. — 511, Air Valves. — 512, Union of High and Low Services. — 513, Combined Reservoir and Direct Systems. — 514, Stand Pipes. — 515, Fric- tional Heads in Service-Pipes. CHAPTER XXIII. CLARIFICATION OF WATER.— Page 530. Art. 516, Rarity of Clear Waters. — 517, Floating Debris. — 518, Mineral Sedi- ments. — 519, Organic Sediments. — 520, Organic Solutions. — 521, Natural Processes of Clarification — 522, Chemical Processes of Clarification. — 523, Charcoal Process. — 524, Infiltration. — 525, Infiltration Basins. — 526, Ex- amples of Infiltration. — 527, Practical Considerations. — 528, Examples of European Infiltration. — 529, Example of Intercepting Well. — 530, Filter Beds. — 531, Settling and Clear-Water Basins. — 532, Introduction of Filter-Bed System. — 533. Capacity of Filter Beds. — 534, Cleaning of Filter Beds. — 535, Renewal of Sand Surface.— 536, Basin Coverings. CHAPTER XXIV. PUMPING OF WATER— Page 557. “Art. 537, Types of Pumps. — 538, Prime Movers. — 539, Expense of VariibJ* Delivery of Water — 540, Variable Motions of a Piston. — 541, Ratios of Variable Delivery of Water. — 542, Office of Stand-Pipe and Air-Vessel.— xviii CONTENTS. 543, Capacities of Air-Vessels. — 544, Valves. — 545, Motions of Water through Pumps. — 546, Double-Acting Pumping Engines. — 547, Geared Pumping Engines. — 548, Costs of Pumping Water. — 549, Duty of Pumping Engines. — 550, Special Trial Duties. — 551, Economy of a High Duty. CHAPTER XXV. TANK STAND-PIPES. Art. 552, Their Function. — 553, Foundations. — 554, Wind Strains. — 555, Ten- dency to Slide. — 556, Tendency to Overturn. — 557, Tank Materials. — 558, Riveting. — 559, Pressures in Inclosed Stand-Pipes. — 560, Factors of Safety. — 561, Grades of Metals. — 562, Limiting Depths and Thicknesses of Metals. — 563, Thicknesses of Metals Graphically Shown. — 564, Exposed Stand-Pipes. — 565, Stand-Pipe Data. CHAPTER XXVI. SYSTEMS OF WATER SUPPLY.— Page 603. Art. 566, Permanence of Supply Essential. — 567 , Methods of Gathering and Delivering Water. — 568, Choice of Water. — 569, Gravitation. — 570, Pumping with Reservoir Reserve. — 571, Pumping with Direct Pressure. LIST OF TABLES. Table No. Page 1. Population, Families, and Dwellings in Fifty American Cities 32 1 a. Population, Families, and Dwellings in One Hundred American Cities in 1880 33a lb. Water Supplied to European Cities 36 2. Water Supplied, and Piping in several Cities 38 3. Water Supplied in years 1870 and 1874 39 4. Average Gallons of Water Supplied to each Inhabitant 40 5. Ratios of Monthly Consumption of Water in 1874 43 6. Mean Rainfall in different River Basins 51 7. Rainfall in the United States 53 8. Volumes of Rainfall per minute for given inches of Rain per twenty- four hours 62 9. Flood Volumes from given Watershed Areas 67 10. Summary of Rainfall upon the Cochituate Basin 72 11. Summary of Rainfall upon the Croton Basin 72 12. Summary of Rainfall upon the Croton West-Branch Basin 73 13. Summary of Percentage of Rain Flowing from the Cochituate Basin, 73 14. Summary of Percentage of Rain Flowing from the Croton Basin. ... 73 15. Summary of Percentage of Rain Flowing from the Croton West- Branch Basin 74 16. Summary of Volume of Flow from the Cochituate Basin 74 17. Summary of Volume of Flow from the Croton Basin 74 18. Summary of Volume of Flow from the Croton West-Branch Basin.. 75 19. Estimates of Minimum, Mean, and Maximum Flow of Streams.... 75 20. Monthly Ratios of Flow of Streams 76 21. Ratios of Mean Monthly Rain and Inches of Rain Flowing each Month 77 22. Equivalent Volumes of Flow for given Depths of Rain in One Month 82 23. Equivalent Volumes of Flow for given Depths of Rain in One Year. 83 23a. Statistics of Flow of Sudbury River, Mass 83d 23 b. Summary of Rainfall on the Sudbury Basin 83a 23^. Percentage of Rainfall Flowing from the Sudbury Basin 83^ 23 d. Volume of Flow from the Sudbury Basin 83^ LIST OF TABLES. Tabic No. Page 24. Evaporation from Water 89 25. Mean Evaporation from Earth 89 26. Monthly Ratios of Evaporation from Reservoirs 92 27. Multipliers for Equivalent Inches of Rain Evaporated 92 17a. Ratios and Equivalent Inches of Rain 93 27 b. Monthly Gains and Losses in Storage Reservoirs 93 28. Monthly Supply to and Draft from a Reservoir (with Compensation). 96 29. Monthly Supply to and Draft from a Reservoir (without Compensa- tion 97 30. Ratios of Monthly Rain, Flow, Evaporation, and Consumption 101 30a. Estimate of Collectible Rainfall ... 101 31. Percolation of Rain into One Square Mile of Porous Soil in 32. Analyses of Various Lake, Spring, and Well Waters 117 33. Analyses of Various River and Brook Waters 118 34. Analyses of Various Streams in Massachusetts 120 35. Analyses of Various Water Supplies from Domestic Wells 121 36. Artesian Well Temperatures 127 36a. Analyses of Ice from a Stagnant Pond 136 37. Analyses of Various Mineral Spring Waters 143 38. Weights and Volumes of Water at Different Temperatures 166 39. Pressures of Water at Stated Depths 172 40. Correspondent Heights, Velocities, and Times of Falling Bodies. . . 190 41. Coefficients from Michelotti’s Experiments with Orifices 198 42. Coefficients from Bossut’s Experiments with Orifices 199 43. Coefficients from Rennie’s Experiments with Orifices 199 44. Coefficients from Lespinasse’s Experiments with Orifices 201 45. Coefficients from General Ellis’s Experiments with Orifices 203 46. Coefficients for Rectangular Orifices (vertical) 205 47. Coefficients for Rectangular Orifices (horizontal) 206 48. Castel’s Experiments with Convergent Tubes 217 49. Venturi’s Experiments with Divergent Tubes 219 50. Eytelwein’s Experiments with Compound Tubes 220 51. Coefficients of Efflux ( c ) for Short Pipes 227 520. Experimental Coefficients of Flow, by H. Smith Jr 236 52. Experimental Coefficients of Flow ( in ) by Darcy 237 53. Experimental Coefficients of Flow (in) bj^ Fanning 238 54. Experimental Coefficients of Flow ( m ) by Du Buat 238 55. Experimental Coefficients of Flow (ot) by Bossut 238 56. Experimental Coefficients of Flow ( in ) by Couplet 239 57. Experimental Coefficients of Flow (in) by Provis 239 58. Experimental Coefficients of Flow ( m ) by Rennie 239 59. Experimental Coefficients of Flow {in) by Darcy 240 60. Experimental Coefficients of Flow (in) b}^ General Greene and others 240 61. Tabulated Series of Coefficients of Flow (in) 242 62. Coefficients for Clean, Slightl) r Tuberculated, and Foul Pipes 24S 63. Various Formulas for Flow of Water in Pipes 254 64. Velocities (v) for given Slopes and Diameters 259 LIST OF TABLES. xxi Table No. Page 65. Tables of h and Ji due to given Velocities 264 66. Values of c v , and c for Tubes 267 66 a. Coefficients (r) for Smooth Cast-iron Pipes 268 66 b. Coefficients for Classified Rough Pipes 269a 66r. Tables of Values of b, n , and m for given Diameters i~\c 67. Coefficients of Resistance in Bends 274 68. Experimental Weir Coefficients 288 69. Coefficients for given Depths upon Weirs 2S9 70. Discharge for given Depths upon Weirs 290 71. Weir Coefficients by Castel 291 72. Series of Weir Coefficients by Smeaton and others 291 73. Coefficients for Wide Weir-crests 294 73 a. Computed Weir Volumes 298a 74. Observed and Computed Flows in Canals and Rivers 307 75. Coefficients (pi) for Open Channels 308 75 a. Coefficients, Classified for Channels 308c 76. Various Formulas for Flow in Open Channels 310 76 a. Current Meter Rating Experiments 325a 77. Weights of Embankment Materials 341 78. Angles of Repose, and Frictions of Embankment Materials 345 79. Dimensions of Water Supply and Irrigation Canals 373 79 a. Dimensions of Irrigation Canals 376# 80. Waste-Weir Volumes for given Depths 380 81. Lengths and Discharges of Waste-Weirs and Dams 381 81a. Data of Flood Flow of Streams 381^ 82. Thicknesses of Masonry Weirs and Dams 387 83. Heights of Reservoir and Lake Waves 388 84. Coefficients of Masonry Frictions 396 85. Computed Pressures in Masonry 403 86. Limiting Pressures upon Masonry 404 87. Dimension of Walls to Retain Water 406 88. Dimension of Walls to Sustain Earth 420 89. Thicknesses of a Curved-face Wall 422 90. Hydraulic Mean Radii for Circular Conduits 442 90 a. Velocities in the Sudbury Conduit 443 90 b. Coefficients for the Croton New Aqueduct 44/ 91. Conduit Data 445 9i i8 o 7,427 5 - 0 * 6,688 5 56 Indianapolis, Ind 27 48,244 9,200 5-24 7,820 6.17 Jersey City, N. J *7 82,546 16,687 4-95 9,867 8-37 Kansas City, Mo 38 32,260 5,585 5.78 5,424 5 95 Lawrence, Mass 45 28,921 5,287 5-47 3,443 8.40 Louisville, Ky 14 *00,753 * 9 ,i 77 5.25 14,670 6 87 Lowell, Mass 3 i 40,928 7,649 5-35 6,362 6.43 Lynn, Mass 49 28,233 6,100 4.63 4,625 6.10 Memphis, Tenn 32 40,226 7,824 5.14 6,408 6.28 Milwaukee, Wis *9 71,440 14,226 5.02 * 3,048 5-48 Mobile, Ala 39 32,034 6,301 5 .o 8 5,738 5-58 Newark, N. J 13 105,059 21,631 4.86 * 4 , 35 ° 7-32 New Haven, Conn. . . . 2 5 50,840 10,482 4.85 8,100 6.28 New Orleans, La 9 191,418 39 ,i 39 4.89 33,656 5-69 New York, N. Y 1 942,292 185,789 5.07 64,044 14.72 Paterson, N. T 37 33,579 7,048 4.76 4,653 7.22 Philadelphia, Pa 2 674,022 127,746 5.28 112,366 6.01 Pittsburg, Pa. 16 86,076 16,182 5 - 3 2 14,224 6.05 Portland, Me 41 3 i, 4 i 3 6,632 4.74 4,836 6.50 Providence, R. I 21 68,904 * 4,775 4.66 9,227 7.46 Reading, Pa 3 6 33,930 6,932 4.89 6,294 5-39 Richmond, Ya 24 51,038 9,792 5-21 8,033 6-35 Rochester, N. Y 22 62,386 12,213 5 - 1 * 11,649 5-36 San Francisco, Cal. . . . 10 * 49,473 30,553 4.89 25,905 5-77 Savannah, Ga 48 28,235 5 , 0*3 5-63 4 , 56 i 6.19 Scranton, Pa 35 35,°92 6,642 5.28 5,646 6.21 St. Louis, Mo 4 3*0,864 59 , 43 * 5-23 39,675 7.84 Syracuse, N. Y 29 43 >° 5 * 8,677 4.96 7,088 6.07 Toledo, Ohio 40 31,584 6,457 4.89 6,069 5.20 Troy, N. Y 28 46,465 9,302 5.00 5,893 7.88 Utica, N. Y 46 28,804 5,793 4-97 4,799 6.00 Washington, D. C 12 109,199 2 i ,343 5-12 * 9,545 5-59 Wilmington, Del 43 30,841 5,808 5 - 3 * 5,398 5 - 7 * Worcester, Mass 3 ° 41,105 8,658 4-74 4,922 8-35 3 33 a STATISTICS OF HUNDRED AMERICAN CITIES. TABLE No. la. Population, Families, and Dwellings in ioo American Cities in THE \EAR 1880. ( Front the U. S. Census of 1880.) CITIES. Size. Population. Families. Dwellings. Number. Persons to a family. Number. Persons to a dwelling Albany, N. Y 21 90,758 18,297 4.96 13,259 6.85 Allegheny, Pa 23 78,682 14,747 5-34 IU 943 6,59 Atlanta, Ga 49 37,409 7,799 4.80 6,494 5.76 Auburn, N. Y 84 21,924 4,417 4.96 3,879 5-65 Augusta, Ga 86 21,891 4,998 4.38 3,938 5.56 Baltimore, Md 7 332,313 65,356 5.08 50,833 6.54 Bay ( 'it)', Mich 95 20,693 3,728 5-55 3,244 6.38 Boston, Mass 5 362,839 72,763 4.99 43,944 8.26 Bridgeport, Conn. . . 7 i 27.643 5,958 4.64 3,735 7.40 Brooklyn, N. Y 3 566,663 115,076 4.92 62,233 9. II Buffalo, N Y 13 155,134 30,946 5 -oi 23,680 6.55 Cambridge, Mass. . . 3 i 52,669 10,833 4.86 8,260 6.38 Camden, N. J 44 41659 8,772 4-75 8,246 5.05 Charleston, S’. C 36 49,984 11,406 4.38 6,552 7.63 Chelsea, Mass 88 21,782 4,834 4-51 3,725 5-85 Chicago, 111 4 503,185 96,992 5-19 61,069 8.24 Cincinnati, Ohio. . . . 8 255439 52,025 4.90 28,017 9. II Cleveland, Ohio II 160,146 32 ,H 3 4.99 27.1S1 5-89 Columbus, Ohio .... 33 51.647 9,396 5-50 8,527 6.06 Covington, Ky 65 29,720 6,076 4.89 4 , 79 2 6.20 Davenport, Iowa. . . . 87 21,831 4,544 4.80 4,342 5.03 Dayton, ( iliio 47 38,678 8,106 4-77 6,990 5-53 Denver, Col 50 35,629 5,945 5-99 5,279 6.75 Des Moines, Iowa.. . 80 22,408 4,359 5-14 4 U 7 o 5-37 Detroit, Mich 18 116,340 23,290 5.00 20,493 5-68 Dubuque, Iowa 81 22,254 4,281 5.20 3 -S 74 5-74 Elizabeth, N. I 69 28,229 5.332 5-29 4,308 6-55 Elmira, N. Y 97 20,541 4.431 4.64 3,810 5-39 Erie, Pa 70 27.737 5,294 5-24 4,903 5.66 Evansville, Ind 66 29,280 5,803 5-05 5,296 5-53 Fall River, Mass. . . . 37 48,961 9,706 5.04 5,594 8.75 Fort Wayne, Ind. . . . 74 26,880 5,455 4-93 4,866 5-52 Galveston, Texas. . . . 82 22,248 4,670 4.76 4.221 5-27 Grand Rapids, Mich. 58 32,016 6,817 4.70 5,752 5-57 Harrisburg, Pa 60 30,762 6,429 4.78 5.967 5 - 16 Hartford, Conn 43 42,015 9 U 37 4.60 5,736 7 • 3 2 Hoboken. N. J 59 30,999 6,717 4.62 2.695 11.50 Holvoke, Mass 85 21,915 3,881 5.65 2,084 10.52 Indianapolis, Ind.. . . 24 75,056 15,650 4.80 13,727 5-47 Jersey City, N. J . . . . 17 120,722 23,957 5-04 14,049 8.59 Kansas City, Mo. . . . 30 55,785 9.347 5-97 8,609 6.48 Lancaster, Pa 77 25,769 5,379 4-79 5 A 33 5-02 Lawrence, Mass 46 sgusi 7,488 5-23 4, 60S 8.50 Louisville, Ky l6 123,758 24,343 5.08 iS.SgS 6-55 Lowell, Mass 27 59,475 n ,439 5-20 8.245 7.21 Lynn, Mass 48 38,274 8,209 4.66 6.315 6.06 Manchester, N. H . . . 56 32,630 6,338 5-15 3.589 9.09 Memphis, Tenn 54 33,592 7,943 4.23 7 U 74 4.68 STATISTICS OF HUNDRED AMERICAN CITIES, 335 Population, Etc., in Hundred American Cities. — (Continued.) Families. Dwellings. CITIES. Size. Population. Number. Persons to a lamily. Number. Persons to a dwelling. Milwaukee, Wis 19 115.587 23,024 5.02 18,748 6.17 Minneapolis, Minn. . 38 46,887 8,584 5.46 6,932 6.76 Mobile, Ala 68 29.132 6,133 4-75 5,276 5-52 Nashville, lenn 40 43 350 8,525 5.09 7,072 6.13 Newark, N. I 15 136,508 28,386 4.-81 18,796 7.26 New Bedford, Mass.. 75 26,845 6,147 4-37 5,038 5-33 New Haven, Conn.. . 26 62,882 13,638 4.61 9,961 6.31 New Orleans, La. . . . IO 216,090 45,316 4-77 36,347 5-95 Newport, Ky 98 20,433 4,111 4-97 3.225 6-34 New York, N. Y.... I 1,206,299 243,157 4.96 73,684 16.37 Norfolk, Va 83 24,966 5,098 4.31 3.277 6.70 Oakland, Cal 5 i 34.555 7,018 4.92 6,416 5-39 Omaha, Neb 63 30.518 5,612 5-44 5,110 5-97 Oswego, N. Y 92 21,116 4,398 4.80 4,153 5.08 Paterson, N. J 34 5 L 03 I 10,679 4.78 6,712 7.60 Peoria, 111 67 29.259 5,879 4.98 5,482 5-34 Petersburg, Va 89 21,656 4,779 4-53 3,426 6.32 Philadelphia, Pa 2 847,170 165,044 5-13 146,412 5-79 Pittsburg, Pa 12 156.389 29,868 5-24 24,289 6-44 Portland, Me 53 33 . 8 io 7,295 4-63 5.157 6.56 Poughkeepsie, N. Y. 99 20,207 4,302 4.70 3,403 5-94 Providence, R. I 20 104,857 23,178 4-52 14,153 7.41 Ouincy, 111 73 27,268 5,532 4-93 4,715 5-78 Reading, Pa 41 43.278 8,876 4.88 8,267 5-24 Richmond, Va 25 63,600 12,180 5.22 9.532 6.67 Rochester, N. Y 22 89,366 18,039 4-95 15,825 5-65 Sacramento. Cal 90 21,420 4,752 4-51 4,222 5-07 St. Joseph, Mo 57 32,431 5,630 5.76 5.260 6.17 St. Louis, Mo 6 350,518 65,142 5-38 43,026 8.15 St Paul, Minn 45 4 L 473 7,224 5-74 6,343 6-54 Salem, Mass 72 27,563 6,167 4-47 4,241 6.50 Salt Lake City, Utah. 93 20,768 4,207 4-94 3,755 5-53 San Antonio. Texas. . 96 20,550 3,864 5-32 3,632 5.66 San Francisco, Cal.. . 9 233,959 43.463 5.38 34,110 6.86 Savannah, Ga 62 30,709 6,684 4-59 5,572 5 - 5 i Scranton, Pa 39 45,850 8,926 5-14 7,334 6.25 Somerville, Mass. .. 78 24.933 5,417 4.60 4,106 6.07 Springfield, 111 100 19,743 3 , 9 l6 5-04 3,525 5.60 Springfield, Mass.. . . 55 33.340 7,368 4-52 5,033 6.62 Springfield, Ohio. . . . 94 20,730 4.339 4.78 3,786 5-48 Syracuse, N. Y 32 5 L 792 11,046 4.69 8,825 587 Taunton, Mass 9 i 21,213 4.450 4-77 3,261 6. si Terre Haute, Ind. . . . 76 26,042 5,078 5-13 4,581 5-68 Toledo, Ohio 35 50437 10,191 4.92 9,717 5.16 Trenton, N. J Troy, N. Y 64 29,910 5,472 5-47 5,115 5.85 29 56,747 11,491 4.94 6,955 8.16 Utica, N. Y 52 33 . 9 H 6,996 4-85 5,815 5-83 Washington, D. C. . . 14 147.293 29,603 4.98 24,107 6. ii Wheeling, W. Va. . . . 6l 30,737 6,233 4-93 5,128 5-99 Wilkesbarre, Pa 79 23,339 - 4.424 5-28 4,157 5.61 Wilmington, Del. . . . 42 42,478 8,243 5-15 7,641 5-56 Worcester, Mass .... 28 58,291 11,931 4.89 6,634 8.79 33c STATISTICS OF LARGER AMERICAN CITIES TABLE No. lb. Populations in 1900, of 142 American Cities. Cities New York, N. Y Chicago, 111 Philadelphia, Pa St. Louis, Mo Boston, Mass Baltimore, Md Cleveland, Ohio Buffalo, N. Y San Francisco, Cal. . Cincinnati, Ohio Pittsburg, Pa New Orleans, La Detroit, Mich Milwaukee, Wis Washington, D C... Newark, N. J Jersey City, N. J Louisville, Ky Minneapolis, Minn... Providence. R. I. Indianapolis, Ind. Kansas City, Mo St. Paul, Minn Rochester, N. Y Denver, Col Toledo, Ohio Allegheny, Pa Columbus, Ohio Worcester, Mass Syracuse, N. Y New Haven, Conn . . . Paterson, N. J Fall River, Mass St. Joseph, Mo Omaha, Neb Los Angeles, Cal. . . . Memphis, Tenn Scranton, Pa Lowell, Mass Albany, N. Y Cambridge, Mass Portland, Oregon Atlanta, Ga Grand Rapids, Mich. Dayton, Ohio Richmond, Va Nashville, Tenn Seattle, Wash Hartford, Conn Reading, Pa Wilmington, Del Camden, N. J Trenton, N. J Bridgeport, Conn Lynn, Mass Oakland, Cal Lawrence, Mass New Bedford, Mass.. Des Moines, Iowa. . . , Springfield, Mass Somerville, Mass Troy, N. Y Hoboken, N. J Evansville, Ind Manchester, N. H. . . Utica, N. Y Peoria, 111 Charleston, S. C Savannah, Ga Salt Lake City, Utah San Antonio, Texas. pulation Per cent* Increase 3,347,202 37-8 1,698,57s 54-4 1,293,697 23-5 575,238 27-3 560,892 25.0 508,957 17.1 381,768 46.0 352,387 37-8 342,782 I4.6 325,902 9-7 321,616 34-7 287,104 18.6 283,704 38.7 285,315 39-5 278,718 20.9 246,070 35-3 206,433 26.6 204,731 27.0 202,718 23.0 175,597 32.8 169,164 60.4 , 163,752 23-3 163,065 22.4 162,608 21.4 133,859 25-4 131,822 61.8 129,896 23-3 125,560 42.4 118,421 39-8 108,374 22.9 108,027 32.0 105,171 34-2 104,863 409 102,979 96.8 102,555 — 26.9 102,479 103.3 102,320 58.6 102,026 35-6 94,969 22.2 94,T5i -0.8 91,886 31.2 90,426 94.9 89,872 37-i 87,56s 45-2 85,333 39-3 85,050 4-4 80,865 6.1 80,671 88.3 79,850 50.0 78,961 34-6 76,508 24-5 75»935 30.2 73,307 27-5 70,996 45-2 68,513 22.9 66,960 37-5 62,559 40.0 62,442 53-2 62,139 24.0 62,059 40.4 61,643 53-5 60,651 -0.5 59,364 36.0 59,007 16.2 56,987 29.1 56,383 28.1 56,100 36-7 55,807 i-5 54,244 25-5 53,53i J 9-3 53,32i 4i-5 Cities Duluth, Minn Erie, Pa Elizabeth, N. J Wilkesbarre, Pa •Kansas City, Kan. Harrisburg, Pa Portland, Me Yonkers, N. Y Norfolk, Va Waterbury, Conn. Holyoke, Mass Fort Wayne, Ind . . . Youngstown, Ohio Houston, Texas Covington, Ky Akron, Ohio Dallas, Texas Saginaw, Mich Lancaster, Pa Lincoln, Neb Brockton, Mass.... Binghamton, N. Y.. Augusta, Ga Honolulu, Hawaii., Pawtucket, R. I Altoona, Pa Wheelings W. Va. . Mobile, Ala Birmingham, Ala.. Little Rock, Ark. . Springfield, Ohio. . , Galveston, Texas.. Tacoma, Wash Haverhill, Mass.... Spokane, Wash Terre Haute, Ind. Dubuque, Iowa Quincy, 111 South Bend, Ind. . . Salem, Mass Johnstown, Pa Elmira, N. Y Allentown, Pa Davenport, Iowa. . McKeesport, Pa. . . Springfield. Ill Chelsea, Mass Chester, Pa York, Pa Malden, Mass Topeka, Kan Newton, Mass Sioux City, Iowa.. Bayonne, N. J Knoxville, Tenn... Chattanooga, Tenn. Schenectady, N. Y. Fitchburg, Mass... Superior, Wis Rockford, 111 Taunton. Mass Canton, Ohio Butte, Mont Montgomery, Ala.. Auburn, N. Y East St. Louis, 111. . Joliet, 111 Sacramento. Cal Racine, Wis La Crosse, Wis Williamsport, Pa... Population Per cent Increase • ■ • 52,969 59-9 • ■ • 52,733 29.7 38.0 51,721 37-i ... 51.418 34-1 50, 167 27.3 50,145 37-0 47,931 49-o 33-7 45.859 60.0 45,712 28.2 45,H5 27.4 44,885 35-i 44,633 61.0 42,938 14.8 42,728 54-8 12.0 • • • 42,345 -8-5 41,459 29.5 —27.1 40,063 46.7 39,647 13.2 39,441 18.4 39,306 71.6 39,231 41.9 • ■ • 38,973 28.4 . . . 38,878 12.6 . . . 38,469 23-7 38,415 46.7 38,307 48.0 38,253 19.9 37,789 29.9 37,7H 4-7 37-175 35-6 84.9 36,673 21.3 36,927 19.7 36,252 i5-i 35,999 • • • 35.956 64.9 16.7 . . . 35,936 64.8 ■ ■- 35,672 IS- 4 35,416 40.3 . • • 35,254 311 34,227 65.0 36.8 34,072 22.0 33,998 6S.0 ... 33,708 62.1 46. 1 8-3 37-7 ... 33, nr — 12.4 32,722 7i-9 • • • 32,637 44.8 32,490 11. 6 59- 1 43-o 159-4 31,051 31.6 ... 31.036 21.9 17.0 30,470 184.1 . . . 30.346 3 s.6 • - . 30,345 J 7-3 . . . 29,655 95-4 26.1 10.9 38-4 15- 1 5-9 LABORATORY, MOUNT PROSPECT, BROOKLYN, Page 33 d. 34 QUANTITY OF WATER REQUIRED. 10. Approximate Consumption of Water. — In American cities, having well arranged and maintained sys- tems of water supply, and furnishing good wholesome water for domestic us.e, and clear soft water adapted to the uses of the arts and for mechanical purposes, the average consumption is found to he approximately as follows, in United States gallons : (a.) For ordinary domestic use, not including hose use, 20 gallons per capita per day. (. b .) For private stables, including carnage washing, when reckoned on the basis of inhabitants, 3 gallons per capita per day. (c.) For commercial and manufacturing purposes, 5 to 15 gallons per capita per day. (i d .) For fountains, drinking and ornamental, 3 to 10 gallons per capita per day. (e.) For tire purposes, ^ gallon per capita per day. {/.) For private hose, sprinkling streets and yards, 10 gallons per capita per day, during the four dryest months of the year. (g. ) Waste to prevent freezing of water in service-pipes and house-fixtures, in Northern cities, 10 gallons per capita per day, during the three coldest months of the year. (h.) Waste by leakage of fixtures and pipes, and use ;or flushing purposes, from 5 gallons per capita per day upward. The above estimates are on the basis of the total popu- lations of the municipalities. There will be variations from the above approximate general average, with increased or decreased consumption for each individual town or city, according to its social and business peculiarities. WATER SUPPLIED TO ANCIENT CITIES. 35 The domestic use is greatest in the towns and cities, and in the portions of the towns and cities having the greatest wealth and refinement, where water is appreciated as a luxury as well as a necessity, and this is true of the yard sprinkling and ornamental fountain use, and the private stable use. The greatest drinking-fountain use, and fire use, and general waste, will ordinarily be in the most densely- populated portions, while the commercial and manufactur- ing use will be in excess where the steam-engines are most numerous, where the hydraulic elevators and motors are, on the steamer docks, and where the brewing and chemical arts are practiced. The ratio of length of piping to the population is greater in wealthy suburban towns than in commercial and manu- facturing towns. * Some of these peculiarities are brought out in a follow* ing table of the quantity of water supplied and of piping in several cities, which is based upon the census table hereto- fore given and upon various water-works reports for the year 1870. The general introduction of public water- works, on the constant- supply system, with liberal pressures in the mains and house-services, throughout the American towns and cities, has encouraged its liberal use in the households, so that it is believed that the legitimate and economical domes- tic use of water is of greater average in the American cities than in the cities of any other country, at the present time, and its general use is steadily increasing. 11. Water Supplied to Ancient Cities. — The sup- plies to ancient Jerusalem, imperial Rome, Byzantium, and Alexandria, were formerly equal to three hundred gallons per individual daily ; and, later, the supplies to Nismes, 36 QUANTITY OF WATER REQUIRED. Metz, ancl Lyons, in France, and Lisbon, Segovia, and Seville, in Spain, were most liberal, but a small proportion only of the water supplied from these magnificent public works was applied to domestic use, except in tlie palaces of those attached to the royal courts. 12 . Water Supplied to European Cities. — In the year 1870, the average daily supply to some of the leading European cities was approximately as follows : CITIES. Imp. Gallons. London, England Manchester, “ Sheffield, Liverpool, “ Leeds, “ Edinburgh, Scotland Glasgow, Paris, France . . . Marseilles, “ .... Genoa, Italy Geneva, Switzerland Madrid, Spain Berlin, Prussia 2 9 24 2 9 2 7 2 3 30 40 3° 40 3° 16 16 18 In the year 1866, public water supplies 0 were, in vol- ume, as follows, in the cities named : CITIES. Population. Supply per Capita. Hamburg, Prussia 200,000 34 gals. Altona, “ 5 2 , 000 20 “ Tours, France 42,000 22 “ Angers, “ 53;°°° 1 1 -5 ‘‘ Toulouse, “ ... 100,000 I 3.-5 “ Nantes, “ I 12,000 13.6 “ Lyons, “ 300,000 22 “ * Vide Kirkwood’s “ Filtration of River Waters.” Van Nostrand. N. Y.. 1869 WATER SUPPLIED TO AMERICAN CITIES. 37 Prof. Rankine gives,* as a fair estimate of the real daily demand for water, per inhabitant, amongst inhabitants of different habits as to the quantity of water they consume, the following, based upon British water supply and con- sumption : Rankine’s Estimate for England. Imp. Gallons per Day. Least. Average. Greatest. Used for domestic purposes Washing streets, extinguishing fires, sup- 7 10 *5 plying fountains, etc 3 3 3 Trade and manufactures 7 7 7 Waste under careful regulations, say. . . . 2 2 2 i z 2 Total demand l 9 22 2 7i 13. Water Supplied to American Cities.— The lim- ited use of water for domestic purposes in many of the European cities during the last half century, led the engi- neers who constructed the pioneer water-works of some of the American States to believe that 30 gallons of water per capita daily would be an ample allowance here ; and in them day there was scarce a precedent to lead them to anticipate the present large consumption of water for lawn and street sprinkling by hand-liose, or for waste to prevent freezing in our Northern cities. The following tables will show that this early estimated demand for water has been doubled, trebled, and in some instances even quadrupled ; and this considerable excess, to which there are few exceptions, has been the cause of much annoyance and anxiety. * “ Civil Engineering,” London, 1872, p. 731. 38 QUANTITY OF WATER REQUIRED. In the year 1870, the average daily supply to some of the American cities was as follows, in United States gallons : TABLE No. 2. Water Supplied and Piping in Several Cities, in the year 1870? CITIES. Popula- tion in 1870. Supply per Person, Daily Average Supply per Family, Daily Average. Supply per Dwelling, Daily Average. Total Daily Supply, Average. to « 1 H „• <- \ n * 5 it h * Gallons . Gallons . Gallons . Gallons . Miles . Allies . Baltimore .... 267,354 52.81 282.53 35°-!3 14,122,032 214 0.80 Boston 250,526 60.15 3 12 - 78 508.87 15,070,400 194 0.78 Brooklyn .... 396,099 47. r6 233-44 407.46 18,682,2 19 258 0.65 Buffalo 58.08 306.08 374-°4 6,838,303 56 0.48 Cambridge . . . 39, 6 34 43 - 9 ° 220.38 273-94 1,739,869 60 1.64 Charlestown. . 28,323 43 - 9 ° 201.94 282.72 1,243,38° 25 °- 9 c Chicago 298,977 62.32 3 I 3-47 417-54 18,633,000 240 0.81 Cincinnati . . . 216,239 40.00 201.60 352-40 10,812,609 132 0.61 Cleveland. . . . 92,829 33-24 i6 7-53 184.81 3,085,559 5 ° °-54 Detroit 79,577 64.24 236.98 348.18 5,! 12,493 129 1.61 Hartford 37 , 180 65.81 329 - 7 1 365-90 2,447,000 48 1.3c Jersey City. . . 82,546 83.66 414.12 700.23 6,906,056 70 0.85 Louisville .... 1 °°,7 53 28.95 ! 5!-99 iq8.8q 2,817.300 58 0.58 Montreal, Can. 117,500 49.00 5,720.306 96 0.81 Newark. .... 105,059 20.20 98.17 147.86 2,121,842 52 o- 5 ° New Haven . . 50,840 59.00 286.15 370-52 3,000,000 53 i -°4 New Orleans . 191,418 3°- I 9 i 47- 6 3 171.78 5,779,317 58 0.30 New York . . . 942,292 90.20 457 - 3 1 i, 327-74 85,000,000 346 0.37 Philadelphia . 674,022 S 5 - 11 290.98 33 I- 2 I 37 ,! 45 , 3 8 5 488 071 Salem 24,117 41.46 1 ,000,000 35 !°4 St. Louis .... 310,864 35 - 3 8 185.04 277 - 3 8 1 1,000,000 105 0.34 Washington . . 1 09, 1 99 127.00 650.24 7 ° 9-93 13,868,273 102 O.93 Worcester. . . . 41,105 48.65 230.60 406.23 2,000,000 45 1 °9 The average quantity of water supplied to some of the same cities in 1874 is indicated in the following table, show- ing also the extensions of the pipe systems, and the increase in the average daily consumption of water per capita, from year to year : ~N * See also statistics on pages 625-627. INCREASE IN VARIOUS CITIES. 39 TABLE No. 3 . Water Supplied in Years 1870- and 1874. CITIES Average Daily Supply per Capita. Total Average Daily Supply. Total Miles of Pipes 1870. 1874. 1870. 1874. 187O. 1S74. Boston 60 60 I 5 )° 7 °> 4 00 18,000,000 194 262 Brooklyn 47 58 18,682,219 24,772,467 258 323 Buffalo 58 60 6,838,303 8,509,481 56 87 Cambridge 44 54 L 739>869 2,300,000 60 76 Charlestown . . . 44 62 1,243.380 7 , 6 43, OI 7 25 132 Chicago 64 84 18,633,000 38,090,952 240 386 Cincinnati 40 45 10,812,609 !3, 600, 596 132 x 5 6 Cleveland 32 45 3,085,559 5,625,150 5 ° 81 Detroit 64 87 5, 1 12 ,493 9 , OI 3 , 35 ° 129 *77 Jersey City 84 86 6,906,056 10,42 1,001 70 III Louisville 29 24 2,817,300 3 , 598,730 58 9 1 Newark. . 20 38 2,12 1,842 4 , 73 2 , 7 x8 52 I 12 Philadelphia . . . 55 58 37 , i 45,385 42,111,730 488 625 Salem 41 55 1,000,000 1,380,000 35 40 Washington .... I2 7 138 13,868,273 18,000,000 102 141 Worcester 49 80 2,000,000 3,000,000 45 63 Montreal 49 66 5,720,306 8,395,8io 96 114 14. The Use of Water Steadily Increasing-. — The legitimate use of water is steadily being popularized, calling for an increased average in the amount of household appa- ratus, increased facilities for garden irrigation and jets d'eau, increased street areas moistened in dusty seasons, and increased appliances for its mechanical use ; from all which follows increased waste of water. 15. Increase in Various Cities. — The following table is introduced to show the average daily supply in various cities through a succession of years : 40 QUANTITY OF WATER REQUIRED. TABLE No. 4. Average Gallons Water Supplied to Each Inhabitant Daily in YEAR. Boston. Buffalo. Brooklyn. Cleveland. Cincinnati. Chicago. Detroit. Jersey City. Louisville. Montreal. New York. Philadelphia. Washington. i8 8 55 / 1858 — — — 8 33 4 U 46 75 — — — — — i8 59 — — — 11 40 48 — — — — — — i860 .... — — — 14 — 43 52 77 — — — — — 1861 — — — 16 — 43 53 — 9 — — — — 1862 — — *7 J 9 39 44 58 — 14 — — — — 1863 — — 22 2 I — 43 58 — 12 — — — — 1864 — 26 22 — 4 i 57 — 14 — 62 — — 1865 — — 29 22 — 42 55 77 17 — — — — 1866 55 — 33 22 — 43 60 1 7 — — — — 1867 59 — 36 24 — 5 ° 64 — 1 5 — 62 46 — 1868 62 — 43 25 — 58 67 — l6 — 68 5 1 — 1869 62 — 46 27 — 62 61 — 18 — 84 5 1 — 1870 60 58 47 33 40 63 64 84 29 49 90 55 127 187 1 .... . 54 51 46 3 6 — 73 73 — W 55 85 55 !30 1872 55 6l 50 40 60 75 83 99 22 55 88 54 134 i8 73 58 60 55 43 — 75 90 — 22 60 104 56 138 1874. .... 60 60 58 45 45 84 87 86 24 66 — 58 U 3 S 1882 99 106 55 6 5 76 114 149 124 52 66 79 66 176 1890 io 5 186 — 106 114 138 161 1 18 69 66 — 131 ! 5 8 16. Relation of Supply per Capita to Total Pop- ulation. — In the larger cities there are generally the great- est variety of purposes for which water is required, and consequently a greater average daily consumption per cap- ita. Exceptions to this general rule may be found in a few suburban towns largely engaged in the growth of garden truck, and plants, and shrubs for the urban markets, in which there is a large demand for water for purposes of irrigation. In the New England towns and cities the average daily consumption and waste of water according to population is approximately as follows : MONTHLY AND HOURLY VARIATIONS. 41 Places of 10,000 population, 35 to 45 gallons per capita. “ “ 20,000 “ 40 to 50 “ “ “ “ “ 30,000 “ 45 to 65 “ “ “ “ “ 50,000 “ 55 to 75 “ “ “ Places of 75,000 population and upward, 60 to 100 gal- lons per capita. 17. Monthly and Hourly Variations in the Draught. --The data heretofore given relating to the daily average consumption of water have referred to annual quantities reduced to their daily average. The daily draught is not, however, uniform throughout the year, but at times is greatly in excess of the average for the year, and at other times falls below. It may be twenty to thirty per cent, in excess during several consecutive weeks, fifty jjer cent, during several consecutive days, and not infrequently one hundred per cent, in excess during several consecutive hours, independ- ently of the occasional heavy drafts for fires. Diagrams of this daily consumption of water in the cities usually show two principal maxima and two principal minima. The earliest maximum in the year occurs, in the Eastern and Middle States, about the time the frost is deepest in the ground and the weather is coldest, that is, between the middle of January and the first of March, and in New ngland cities this period sometimes gives the maximum of the year. The second maximum occurs usually during the hottest and dryest portion of the year, or between the mid- dle of July and the first of September. The two principal minima occur in the spring and autumn, about midway between the maxima. Between these four periods the pro- file shows irregular wavy lines, and a profile diagram continued for a series of years shows a very jagged line. To illustrate the irregular consumption of water, we Fig. 1 . Chicago. Brooklyn. Cincinnati. Montrea. •S33UI3AB A[l|}UOJ^ 'Uiaip J3(i SUO[[Lo UOI[|lOi JO 'OfJ MONTHLY DIAGRAM Ol'' WATER SUPPLIED TO CHICAGO, BROOKLYN, CINCINNATI, AND MONTREAL. IN YEARS 1871, 187a, 1873, AND 187a. RATIO OF MONTHLY CONSUMPTION. 48 have prepared the diagrams, Fig. 1, of the operations of the pumps at Chicago, Brooklyn, Cincinnati, and Montreal, during the years 1871, 1872, 1873, and 1874. 18. Ratio of Monthly Consumption. — The varia- tions in draught, as by monthly classification, in several prominent cities, in the year 1874, have been reduced tr ratios of mean monthly draughts for convenience of compar- ison, and are here presented ; unity representing the mean monthly draught for the year : TABLE No. 5. Ratios of Monthly Consumption of Water in 1874. CITIES. C ■—» Feb. March. April. May. June. July. Aug. Sept. 0 O Nov. Dec. Rrooklyn 1.029 1. 132 .971 .892 .941 I 008 1.069 1-034 I.044 .987 ■ 9 I 9 ■974 3uffalo. 1.008 1.007 .960 .941 •983 ■9 6 3 .996 1.020 I.044 i. on 1.040 I.OOG Cleveland. . . .883 .901 .850 .871 .992 I 180 1.181 1.206 I 058 1. 001 .942 ■915 Detroit .856 .807 ■905 .844 1.029 1.065^ I. 051 1.167 I-I 7 I 1.115 .987 1.003 Philadelphia. .850 .844 •834 .898 I.056 I-I 99 1.289 1-145 I. O9I -990 .952 .853 Chicago .... .862 .844 .904 .904 .942 .942 I.I 7 I 1-193 1.162 I. 03 Q .966 I.O29 Cincinnati.. . .792 .762 .778 .856 I. on 1. 217 I.207 L 257 I.302 1.058 .q6o •799 Louisville. . . .842 .819 .848 .841 .960 1. 192 I.207 1.223 1.202 1.138 •V 40 .876 Montreal .864 •959 943 I .025 .9x6 •9°7 I.IOI 1.151 1.096 1-043 .971 1.023 Mean. . . .887 .897 .888 .897 .960 1075 1.144 I-I 55 1. 130 1.042 .964 .941 There is also a very perceptible daily variation in each week, and hourly variation in each day, in the domestic consumption of water. The Brooklyn diagram shows that the average draught in the month of maximum consumption was in 1872, fifteen per cent, in excess of the average annual draught ; in 1873, seventeen per cent, in excess ; in 1874, thirteen per cent, in excess. A Boston Highlands direct pumping diagram lying be- fore the writer shows that the average draught at nine o’clock in the forenoon was thirty-seven per cent, in excess 44 QUANTITY OF WATER REQUIRED. of the average draught for the three months, and that at eight o’clock a.m. on the Mondays the draught was sixty per cent, in excess of the average hourly draught for the three months. The maximum hourly draught indicated hy the two diagrams taken together is nearly seventy-five per cent, in excess of the average throughout the year. 19. Illustrations of Varying- Consumption. — In illustration, we will assume a case of a suburban town re- quiring, say, an average daily consumption for the year of 1,000,000 United States gallons of water, and compute the maximum rate of draught on the bases shown by the above- named diagrams, thus : Gallons per Day. Gallons per Min. Cubic Feet per Min. Average draught per year Add 17 per cent, for max. monthly average 1,000,000 694.4 92.8 draught, making Add to the last quantity io per cent, for the 1,170,000 812.5 108.6 max. weekly average draught, making. .... Add to the last quantity 37 per cent, for the 1,270,000 881.9 II7.9 max. hourly average draught, making Add to the last Quantity 23 per cent, for the 1,640,000 1,138.9 152.3 max. hourly av. draught on Mondays, making 1,870,000 1,300.0 250.0 The experience of nearly every water-supply shows that the maximum draught, aside from fire-service, is at time* more than double the average draught. 20. Reserve for Fire Extinguishment. — In addi- tion to the above, there should be an ample reserve of water for fire service, and extra conduit and distribution capacity for its delivery. There is a possibility of two or three fires being in progress at the same time, in even the smaller cities, requiring nine to twelve hydrant streams, or say 3 DC' cubic feet of water per minute, for each fire. QUANTITY OF WATER REQUIRED 44 a TABLE No. 5a. Financial and Water Pipe Statistics. Compiled from Tables in the “Journal of the New England Water Works Association,” September , Charles IV. Sherman , Editor. Name of Town e -3 Essex Junction, Vt. . Leicester, Mass. Billerica, Mass Nantucket, Mass Ipswich, Mass Oberlin, Ohio. ....... Reading, Mass Winchendon, Mass . . Wellesley, Mass...... Whitman, Mass...... Andover, Mass Middleboro, Mass Ware, Mass.. Arlington, Mass Keene, N. H... Plymouth, Mass Watertown. Mass Geneva, N. Y .... Attleboro, Mass Leominster, Mass Marlboro, Mass Woburn, Mass New London, Ct Burlington, Vt.. . . . . . Madison, Wis. ....... Concord, N. H Waltham, Mass Lewiston, Me ... Quincy, Mass Atlantic City, N.J — Bay City, Mich Taunton, Mass Fitchburg, Mass Schenectady, N. Y.. Woonsocket. R. I — Newton, Mass Chelsea, Mass Salem, Mass Haverhill, Mass ■ Brockton, Mass 1 Holyoke, Mass Yonkers, N. Y Erie, Penn Manchester, N. H Springfield, Mass New Bedford, Mass — Somerville, Mass Lynn, Mass Wilmington, Del Cambridge, Mass Albany, N. Y. Lowell, Mass Fall River, Mass Worcester, Mass. Providence, R. I. Minneapolis, Minn. Boston, Mass Metrop’n W. W., Mass. I, 125 1*398 2,780 3,002 4*658 4,800 4*969 5,001 5 ,o 7 2 6,172 6,813 6,qoo 8,263 8,603 9 * 3 °° 9*592 9,706 II, 000 ii *335 12,392 13*609 14*254 17*500 . 18,800 19,164 i 9 , 63 2 23*700 23*76 23,896 28,000 28.000 31,006 3 I * 53 I 32.000 32.500 33.587 34.000 35,956 37,17s 40,063 46,204 47 * 93 ! 52*733 56,987 62,059 62.500 62.500 73*6oo 76.500 91,886 94 *i 5 i 95.000 107,623 118,421 187,297 202,718 560,892 815,400 $38,500.00 81.002.87 91.705.87 86,381.42 265,462.18 111,553.03 322,718.24 129,632.93 208,624.48 116,420.15 131,090.08 313,189.09 309,169.56 181.628.73 374,488.18 5 I 9 , 2 I 5-43 586.261.13 597,049.1:4 706,978.44 468.039.73 337.360.13 857,440.98 614,000.00 a ^ "• $5,460.51 5,606.56 4,368.88 15 * 153-99 5,861.37 17,288.52 8,017.75 7 , 758 . 5 t 7 , 875-99 5,144.61 14.727.72 22,421.83 14,857-55 23,970.04 36,200.82 37 , 129.19 54 , 258.18 36 , 740.69 9 7 14 9 26 1 5 30 *7 25 17 11 33 35 37 34 27 3 1 46 37 50 38 34 60 5 1 85,932.11 -30,130.59 114,624.42 88,340.61 26,799.41 77,381.92 182,767.79 147*944.93 138,241.94 274 * 954-75 237 * 484-59 208,823.03 180,333.44 263,208.41 48,370.06 45,999.29 124,529.67 116,014.24 127,000.92 i 36 * 5 I 4 -° I 132 , 937-39 149,820.47 194,087.06 84 47 45 78 66 4 ° 45 136 37 64 8 74 10 3 14 9 12 10 129.5 127. £ 87.3 173-3 330 - 5 269.2 7 I 3 -‘= 1430.] Number of Service Taps Number of Fire Hydrants 96 27 3°5 205 101 929 50 647 137 625 87 1*057 140 388 121 878 270 988 * 5 r 876 196 820 120 727 114 i* 57 o 326 1*725 215 1,894 132 1,583 337 1,679 207 263 326 2,181 343 2,896 352 3,088 258 3*350 213 2,758 169 3*340 267 3,285 33 i 173 4*330 539 4*249 5 I 9 2,201 413 4*502 783 4*432 499 469 2,193 548 7,087 935 6,146 253 5*319 322 5,275 608 3 - 6i ° 860 4,968 771 1,154 595 5*513 343 9,764 955 9,280 738 10,291 897 13*504 952 765 14,207 968 808 10,634 1,098 6.943 954 13,292 1,763 21,566 1,978 20,064 3*!72 87,525 7,606 134,496 11*913 446 QUANTITY OF WATER REQUIRED TABLE No. S b . Water Supply Consumption Statistics. Compiled from Tables in the “Journal of the New England Water Works Association,” September, igoi , Charles W. Sherman, Editor. Name of Town Leicester, Mass Billerica, Mass Nantucket, Mass Ipswich, Mass Oberlin, Ohio Reading, Mass Winchendon, Mass Wellesley, Mass Whitman, Mass Andover, Mass Middleboro, Mass Ware, Mass Arlington, Mass Keene, N. H Plymouth, Mass Attleboro, Mass Marlboro, Mass Woburn, Mass New London, Conn Burlington, Vt Madison, Wis Waltham, Mass Lewiston, Me Nashua, N. H Atlantic City, N. J Bay City, Mich Taunton, Mass Fitchburg, Mass Schenectady, N. Y Woonsocket, R. I Newton, Mass Chelsea, Mass Salem, Mass Haverhill, Mass Brockton, Mass Holyoke, Mass Yonkers, N. Y Erie, Penn Springfield, Mass New Bedford, Mass Lynn, Mass Wilmington, Del Cambridge, Mass Albany, N. Y Lowell, Mass Fall River, Mass Worcester, Mass Providence, R. I Minneapolis, Minn Metropolitan W. W., Mass. 1.398 2,780 3,002 4.658 4,800 4,969 5, 001 5.072 6,172 6,813 6,900 8,263 8,603 9,300 9.592 H .335 13,609 14,254 17.500 18,800 19,164 23,700 23.761 25.000 28.000 28.000 31,006 3i,53i 32.000 32.500 33-587 34.000 35,956 37,175 40,063 46,204 47 , 93 1 52,733 62,059 62.500 73,600 76.500 91,886 94 ,i 5 i 95 .000 107,623 118,421 187,297 202,718 815,4^ a a u < c jO O *aj o •a 52 RAINFALL. Mean Rainfall Along River Courses — ( Continued ). MISSISSIPPI RIVER. Name of Station. Delta New Orleans Baton Rouge June, of Red River . . Vicksburg Memphis Cairo St. Louis Dubuque Lacrosse St. Paul’s Brownsville June. Pecos River . . El Paso Albuquerque Summer. Winter. Y EAR. Distance from Mouth. Inches. Inches. Inches . Miles ( approximate ). 20 18 60 10 j 20 16 60 95 18 15 60 190 14 16 56 24O II 15 55 350 Distances from 8 15 42 560 >- the Gulf of II 12 42 700 Mexico. 13 8 42 850 14 5 38 I IOO II 3 30 1200 II 3 25 1500J RIO GRANDE. 8 6 37 30 1 5 4 3 18 400 Distances from 2 12 800 - the Gulf of Mexico. 3 2 8 1050 J 46 inches. Average rain, 19 inches. COLUMBIA RIVER. Astoria 4 44 86 5") Walla-Walla 2 5 20 275 1 Boise City 2 7 13 600 ( Fort Hall I 6 12 850J Distances from Average rain, the | inrhps Pacific Ocean. inches. Reference to the above, from among the principal river valleys, is sufficient to show that the oft-made statement, that “rain falls most abundantly on the high land,” is applicable, in the United States, to subordinate watersheds only, and in rare instances. 33 . Grouped Rainfall Statistics. — The following table gives the minimum, maximum, and mean rainfalls, according to the most extended series of observations, at various stations in the United States. They are grouped by territorial divisions, having uniformity of meteorological characteristics. RAINFALL IN THE UNITED STATES. 53 TABLE No. 7. Rainfall in the United States. {From Records to 1866 inclusive .) GROUP 1.— Atlantic Sea-coast from Portland to Washington. Station. Lat. Long. Height above Sea. Years of Record Min. Annual Rain. Max. Annual Rain. Mean Annual Rain. Inches. Inches. Inches . Gardiner, Me 44° 10' 69° 46' 76 27 30.19 5 x -47 42.09 Brunswick “ 43 54 69 57 74 32 26.38 75.64 44.68 Worcester, Mass 42 16 71 49 5^ 26 34.60 61.83 46 92 Cambridge, “ ... 42 23 71 07 71 31 30.04 59-34 46.39 Boston, “ 42 22 71 04 28 27.20 67.78 44.99 New Bedford “ 41 39 70 56 90 54 30.68 58.14 41.42 Providence, R. I 4 i 50 7 i 2 3 uo 35 3 °- 5 i 54.17 4!-54 Flatbush, N. Y 40 37 74 °2 54 36 :.z-i 4 58.92 43-52 Fort Hamilton, “ 40 36 74 02 25 *9 29-75 62.69 42.55 Fort Columbus, “ 40 41 74 oi 23 24 27-57 65 - 5 1 43-24 New York City, “ 40 43 74 00 50 3 i 34-79 62.87 43.00 West Point, “ 41 24 73 57 167 20 35-°5 63.56 47-65 Newark, N. J 40 45 74 10 35 23 34-54 57-05 44-85 Lambertville, “ 40 23 74 56 96 17 32-33 57-37 43-99 Philadelphia, PeDn 39 57 75 « 60 43 29-57 62.94 44-05 Baltimore, Md Fort McHenry, “ 39 is 76 37 28 28.75 62.04 42.33 39 16 76 34 36 23 22.87 51-50 41.10 A ashington, t). C 38 54 77 03 no 28 23.24 53-45 37-52 43-44 GROUP 2. — Atlantic Sea-coast, Virginia to Florida. Fortress Monroe, Va Charleston, S. C Fort Moultrie, “ Savannah, Ga Fort Brooke, Fla 37 °oo / 76°i8' 8 19 19.32 74.10 47.04 32 47 79 56 25 12 23.69 56.16 43-63 32 46 79 5 i 25 1 7 33-98 65-31 45-51 32 05 81 05 42 23 25.98 69.93 48.32 28 00 82 28 20 V 35-93 89.86 53-63 47-63 GROUP 3.— Hudson River Valley, Vermont, Newburgh, N. Y Poughkeepsie, “ Kingston, “ Hudson, “ Kinderhook, “ Albany, “ Watervliet Arsenal, “ Lansingburg, “ Granville, “ Hanover, N. H Burlington, Vt Fairfield, N. Y Clinton, “ Utica, “ Lowville, “ Gouverneur, “ Potsdam, “ Cazenovia, “ Oxford, “ Pompey, “ Auburn “ Ithaca, “ Geneva, “ Penn Yan, “ Rochester, “ Middlebury, “ Fredonia, “ New York. 4 i 3 1 ' 74 05' 150 4 i 41 73 55 4 i 55 74 02 *i88 42 13 73 46 150 42 22 73 43 125 42 39 73 44 130 42 43 73 43 50 42 47 73 40 30 43 20 73 17 25O 43 42 72 17 530 44 29 73 11 346 43 05 74 55 I185 43 00 75 20 II27 43 07 75 13 473 43 46 75 32 847 44 25 75 35 400 44 40 75 01 394 42 55 75 46 1260 42 28 75 32 961 42 5 & 76 05 1300 42 55 76 28 650 42 27 76 37 417 42 53 77 02 567 42 42 77 11 740 43 08 77 5 i 516 42 49 78 TO 800 42 26 79 24 710 Northern and Western 20 25.04 55-63 36.61 15 40.36 19 35 -io 15 34-52 17 36.48 28 31.92 5°-97 40.52 17 27.50 44-93 34-65 20 33-31 15 3 x -52 19 3 r -65 55.98 40.32 27 25-45 49.44 34-15 17 36.45 19 56.69 4 r -49 22 27-54 41.14 22 33 - 5 ° 24 15-73 50.75 30 -I 5 20 28.63 25 45.10 20 36.36 16 23.21 45-08 30.75 22 34-42 19 34-71 19 27.46 30.87 3 ° 19.66 44.90 28 42 35 24.97 43-°3 32.56 1 7 3°-44 1 6 36.55 34-99 54 RAINFALL. Rainfall in the United States — ( Continued ). GROUP 4 . — Upper Mississippi, part of Iowa, Minnesota, and Wisconsin. Station. Lat. Long. Height above Sea. Years of Record Min. Annual Rain. Max. Annual Rain. Mean Annual Rain. Inches. Inches. Inches . Fort Ripley, Minn 46° 19' 94 ° I 9 / 1130 17 12.06 36.14 25.11 Fort Snelling, “ 44 53 93 10 820 22 15.07 49.69 25.82 Dubuque, Iowa 42 3 ° 90 40 666 15 25.07 47.19 33-47 Milwaukee, Wis 43 03 87 55 59 1 23 20.54 44.86 30.40 Muscatine, Iowa 41 26 9 1 °5 586 19 23.66 74.20 42.88 Fort Madison, “ 40 37 91 28 600 18 27-54 54 *H 41.96 33*27 GROUP S.— Ohio River Valley, Western Missouri. Pennsylvania to Eastern Alleghany Arsenal, Penn 4 °° 32 ' 8o°o2 / 704 23 25.62 47-79 35.23 Steubenville, Ohio 40 25 80 41 670 37 28.02 57.28 41.48 Marietta, “ 39 25 81 29 580 48 32.46 53*54 42.70 Cincinnati, “ 39 06 84 25 582 3 1 25-49 65.18 44.87 Portsmouth, “ 38 42 82 53 468 26 25.50 56.79 38.33 Athens, 111 39 52 89 56 800 16 25.12 48.17 39.62 St. Louis Arsenal, Mo 38 40 90 10 450 19 24.08 7 X *54 42.63 St. Louis, “ 38 37 90 16 481 28 27.00 68.83 42.18 Jefferson Barracks, “ 38 28 9 ° *5 472 21 29.18 55*13 40.88 d.0.88 GROUP 6.— Indian Territory and Western Arkansas. Fort Gibson, Ind. Ter.. Fort Smith. Ark Fort Washita, Ind. Ter. 3 S° 48 ' 35 23 34 14 95°°3 94 29 96 38 560 460 645 20 22 l6 18.84 24-34 21.81 55-82 61.03 64.29 3G37 40.36 38.04 38.25 GROUP 7 .— Lower Mississippi and Red Rivers ; part of Kentucky. Springdale, Ken.. Washington, Ark. Vicksburg, Miss.. Natchez, “ . 38^07' 85W 570 33 44 93 4 1 660 32 23 90 56 350 3 1 34 9 1 2 5 264 24 30 - 9 1 67.10 48.58 22 41.40 70.40 54 * 5 ° 16 37.21 60.28 49*30 18 31.09 78*73 53-55 51.48 GROUP 8.— Mississippi Delta, and Coast of Mississippi and Alabama. New Orleans, La Mt. V ernon Arsenal, Ala Baton Rouge, La 29 ° 57 ' 90°02' 20 23 41.92 67.12 31 12 88 02 200 u 51*49 106.57 30 26 91 18 41 15 41*34 116.40 51*05 66.14 60. r6 59*12 GROUP 9 .— Pacific Coast, Bay of San Francisco to Alaska. San Francisco, Cal 37 ° 48 ' I22'26' 170 18 IT *73 36.03 1 21.69 Sacramento, “ 38 35 121 28 82 18 n.15 27.44 19.56 Fort Vancouver, YV. Ter 45 4° 122 30 50 l6 25.91 56.09 | 38.84 Fort Steilacoom, “ 47 IO 122 2q 300 l6 25-75 70.21 | 43.98 Sitka, Alaska 57 03 135 18 20 l6 58.6s 95.81 1 83.39 41.49 Fig. 3. No. 1* 1.90 ' 1.80 1.70 1.60 i-5o 1.40 1.30 1.20 1. 10 1 .90 .80 .70 .60 „ No. 8. Atlantic sea-coast, Virginia to Florida. 56 RAINFALL. 34. Monthly Fluctuations in Rainfall. — Our gener- alizations tlius far have referred to the mean annual rainfall over large sections. There is a large range of fluctuation in the average amount of precipitation through the different seasons of the year, in different sections of the United States. It will he of interest to follow out this phase of the question in diagrams 3 and 4, in which type curves * of monthly means are drawn about a line of annual mean covering a series of years, in no case less than fifteen. The letters J, F, M, &c., at the heads of the diagrams, are the initials of the months. The heavy horizontal lines represent means for the year, which are taken as unity. Their true values may he found at the foot of their respect- ive groups in the above table. About this line of annual mean is drawn by free-hand the type curve of mean rain- fall through the successive months, showing for each month its percentage of the annual mean. Each type curve relates to a section of country having uniform characteristics in its annual distribution of rain. Curve No. 1. for Group No. 1, includes the section of country bordering upon the Atlantic sea-coast from Port- land to Washington. The average fluctuation of the year in this section is forty per cent. Its maximum rainfall occurs oftenest in August, and its minimum oftenest in January or February. Curve No. £, for Group No. 2, includes the Atlantic coast border from Virginia to Florida. The average fluc- tuation of the year is one hundred and ninety-eight per cent. Its maximum rainfall occurs oftenest about the first of August, and nearly equal minima in April and October. * Reduced from a diagram by Chas. Schott, C. E., Smithsonian Contribu tion, Vol. XVIII, p. 16. The tables of American rainfall arranged by Mr. Schott, and published in the same volume, are exceedingly valuable. Fig. 4. J F ■ M A M .7 J A SO N D J CURVES OF ANNUAL FLUCTUATIONS IN RAINFALL* Indian Territory and Western ’ Upper Miss., parts of Iowa, Minnesota, 58 RAINFALL. Curve No. 3, for Group No. 3, includes the upper Hud- son River valley, and northern and western New York. The average fluctuation of the year is sixty-six per cent. Its maximum rainfall occurs oftenest near the first of July and its minimum oftenest about the first of February. Curve No. J, for Group No. 4, includes a part of Iowa, central Minnesota, and part of Wisconsin, in the upper Mississippi valley. The average fluctuation of the year is one hundred and nine per cent. Its maximum rainfall occurs oftenest in the latter part of June and its minimum oftenest about the first of February. Curve No. 5, for Group No. 5, includes the Ohio River valley, from western Pennsylvania to eastern Missouri. The average fluctuation of the year is seventy-three per cent. Its maximum rainfall occurs oftenest about the first of June and its minimum oftenest in the latter part of January. Curve No. 6 , for Group No. 6, includes the Indian Ter- ritory and Western Arkansas. The average fluctuation of the year is ninety-one per cent. Its maximum rainfall occurs oftenest about the first of May and its minimum oftenest at the opening of the year. Curve No. 8 , for Group No. 8, includes the Mississippi Delta and Gulf coast of Alabama and Mississippi. The average fluctuation of the year is seventy -five per cent. Its maximum rainfall occurs oftenest in the latter part of July and its minimum oftenest early in October. A similar type curve for Group No. 9, the region border- ing upon the Pacific coast from the Bay of San Francisco to Puget’s Sound, would show an average annual fluctua- tion through the seasons of two hundred and thirty -two per cent. The fluctuations here have nothing in common with the Mississippi and Atlantic types. The maximum Fig. 5. CURVES OF SECULAR FLUCTUATIONS IN RAINFALL. 60 RAINFALL. rainfall here occurs oftenest in December and the minimum oftenest in July. 85. Secular Fluctuations in Rainfall. — Diagram 5 illustrates the secular fluctuations in the rainfall through a long series of years in the Atlantic system and in the central Mississippi system. It presents the successions of wet and dry periods as they vibrate back and forth about the mean of the whole period. The extreme fluctuation is in the first case twenty-eight per cent., and in the second case thirty per cent. 36. Focal, Physical, anti Meteorological Influ- ences. — The above statistics give sufficient data for deter- mining approximately the general average rainfall in any one of the principal river-basins of the States. There are local influences operating in most of the main physical divisions, analogous to those governing rainfall in the grand atmospheric systems. Referring to any local watershed, and the detailed study of such is oftenest that of a limited gathering ground tribu- tary to some river, we have to note especially the mean temperature and capacity of the atmosphere to bear vapor, the source from which the chief saturation of the atmos- phere is derived, the prevailing winds at the different sea- sons, whether in harmony with or opposition to the direction of this source, and if any high lands that will act as con- densers of the moisture lie in its path and filch its vapors, or if guiding ridges converge the summer showers in more than due proportion in a favored valley. A careful study of the local, physical, and meteorological influences will usually indicate quite unmistakably if the mean rainfall of a subordinate watershed is greater or less than that of the main basin to which its streams are tributary. There is rarely a sudden change of mean precipitation, except at the GREAT RAIN STORMS. 61 crest of an elevated ridge or tlie brink of a deep and narrow ravine. 37. Uniform Effects of Natural Laws. — When studies of local rain-alls are confined to mean results, neglecting the occasional wide departures from tlie influence of the general controlling atmospheric laws, the actions of nature seem precise and regular in their successions, and in fact we find that the governing forces hold results with a firm bearing close upon their appointed line. But occasionally they break out from their accustomed course as with a convulsive leap, and a storm rages as though the windows of heaven had burst, and floods sweep down the water-courses, almost irresistible in their fury. If hydraulic constructions are not built as firm as the ever- lasting hills, their ruins will on such occasions be borne along on the flood toward the ocean. 38. Great Rain Storms. — In October, 1869, a great storm moved up along the Atlantic coast from Virginia to New York, and passed through the heart of New England, with disastrous effect along nearly its whole course. Its rainfall at many points along its central path was from eight to nine inches, and its duration in New England was from forty to fifty-nine hours. In August, 1874, a short, heavy storm passed over east- ern Connecticut, when there fell at New London and at Norwich twelve inches* of rain within forty-eight hours, five inches of which fell in four hours. Such storms are rare upon the Atlantic coast and in the Middle and 'West- ern States. Short storms of equal force, lasting one or two hours, are more common, and the flood effects from them, on hilly * From data supplied by H. B. Winsbip, Supt. of Norwich Water-works. 62 RAINFALL. watersheds, not exceeding one or two square miles area, may he equally disastrous, and waterspouts sometimes hurst in the valleys and flood their streams. 39. Maximum Ratios of Floods to Rainfalls.— When the surface of a small watershed is generally rocky, or impervious, or, for instance, when the ground is frozen and uncovered hy snow, the maximum rate of volume of flow through the outlet channel may reach two-thirds of the average rate of volume of rain falling upon the gathering- ground. 40. Volume of Water from given Rainfalls. — The rates of volume of water falling per minute, for the rates of rainfall per twenty-four hours, indicated, are given in cubic feet per minute, per acre and per square mile, in the follow- ing table : TABLE No. 8. Volume of Rainfall per Minute, for given Inches per Twenty- four Hours. Rainfall per 24 HOURS. Volume per Minute on One Acre. V OLUME per Minute on One Sq. Mile. Rainfall per 24 HOURS. Volume per Minute on One Acre. Volume per Minute on One Sq. Mile. Inches . Cu. feet. Cu. feet. Inches . Cu. feet. Cu. feet. 0.1 .252 161.33 1 2.521 I 6 i 3 - 3 I .2 • 5°4 322.67 2 5.042 3226.62 •3 • 75 6 484.01 3 7-563 4840.00 •4 1.008 645-33 4 10.084 6453-25 •5 1.264 806.67 5 12.605 8066.56 .6 i- 5 i 5 968.00 6 15.126 9679.87 -7 1-765 1122.73 7 17.647 1 1293.18 .8 2.107 1390.67 8 20.168 12906.50 •9 2.269 1450.00 9 10 22.689 25.200 14529.81 16133.12 41. Gauging Rainfall. — A pluviometer. Fig. 6. is used to measure the amount of rain that falls from the sky. It is a deep, cylindrical, open-topped dish of brass. Its ton GAUGING RAINFALL. 63 edge is thin, so it will receive just the rain due to the sec- tional area of the open top. A convenient size is of two inches diameter at a, and at b of such diameter that its sectional area is exactly one-tentli the sec- tional area at a, or a little more than one-half inch. When extreme accuracy is re- quired, the diameter at a is made ten inches and at & a little more than three inches, still maintaining the ratio of sectional areas ten to one, the displacement of the meas- uring-rod being allowed for. This rain-gauge should be set vertically in a smooth, open, level ground, and the grass around be kept smoothly trimmed in summer. The top of a ten-inch gauge is set at about one foot above the surface of the ground, and of smaller gauges, clear of the grass surface. The gauge should be placed sufficiently apart from buildings, fences, trees, and shrubs, so that the volume of rain gathered shall not be augmented or reduced by wind- eddies. If such a situation, secure from interference by animals or by mischievous persons, is not obtainable, the gauge may be set upon the flat roof of a building, and the height above the ground noted. The measuring-rod for taking the depth of rain in b is graduated in inches and tenths of inches, so that when the sections of a and b are ten to one , ten inches upon the rod 64 RAINFALL. corresponds with one inch of actual rainfall, and one inch on the rod to one-tenth inch of rain, and one-tenth on the rod to one-lnindredth of rain. Snow is caught in a cylindrical, vertical- sided dish, not less than ten inches diameter, melted, and then measured as rain. Memorandums of d.epths of snow before melting, with dates, are preserved also. It has been observed at numerous places, that elevated pluviometers indicated less rain than those placed in the neighboring ground. When there is wind during a shower, the path of the drops is parabolic, being much inclined in the air above and nearly vertical at the surface of the ground. A circular rain-gauge, held horizontally, presents to inclined drops an elliptic section, and consequently less effective area than to vertical drops. The law due to height alone is not satisfactorily estab- lished, though several formulae of correction have been suggested, some of which were very evidently based upon erroneous measures of rainfall. The observed rainfall at Greenwich Observatory, Eng- land, in the year 1855, is reported, at ground level, 23.8 inches depth ; at 22 feet higher, .807 of that quantity, and at 50 feet higher, .42 of that quantity. The observed rainfall at the Yorkshire Museum, Eng- land, in the years 1832, 1833, and 1834, is reported, for yearly average, at ground level, 21.477 inches ; at 44 feet higher, .81 as much, and at 213 feet higher, .605 as much. Unless vigilantly watched during storms, the gauges are liable to overflow, when an accurate record becomes impos- sible. Overflow cups are sometimes joined to rain-gauges, near their tops, to catch the surplus water of great storms. Pis. 127. Fig. 128. i SECTION AND PLAN OF PUMP-HOUSE. CHAPTER IV. FLOW OF STREAMS. 42. Flood Volume Inversely as the Area of the Basin. — A rain, falling at the rate of one inch in twenty- four hoars, delivers upon each acre of drainage area about 2.5 cubic feet of water each minute. If upon one square mile area, with frozen or impervious surface, there falls twelve inches of rain in twenty-four hours, and two-thirds of this amount flows off in an equal length of time, then the average rate of flow will be 215 cubic feet per second. Any artificial channel cut for a stream, or any dam built across it, must have ample flood-way, overfall, or waste-sluice to pass the flood at its maximum rate. The rate of flood flow at the outlet of a watershed is usually much less from a large main basin than from its tributary basins, because the proportion of plains, storage ponds, and pervious soils is usually greater in large basins than in small, and the flood flow is consequently distrib- uted through a longer time. In a small tributary shed of steep slope the period of maximum flood flow may follow close after the maximum rainfall ; but in the main channel of the main basin the maximum flood effect may not follow for one, two, three, or more days, or until the storm upon its upper valley has entirely ceased. 43. Formulae for Flood V olrnnes.— Tlie recorded flood measurements of American streams are few in number, but 5 66 FLOW OF STREAMS. upon plotting sncli data as is obtained, we find their mean curve to follow very closely that of the equation, Q = 200 (M)f, (1) in which M is the area of watershed in square miles and Q the volume of discharge, in cubic feet per second, from the whole area. The coefficient, for ordinary floods, for New England and Appalachian watersheds varies from 130 to 200, and for Eastern Middle-State watersheds varies from 60 to 100, and for tributaries to the Mississippi, on the west, varies from 12 to 50. Among the Indian Professional Papers we find the fol- lowing formula for volume, in cubic feet per second : Q = cx27(M)*. (2) in which c is a co-efficient, to which Colonel Dickens has given a mean value of 8.25 for East Indian practice. Testing this formula by our American curve, we find the following values of c for given areas : Area in sq. miles. . . I. 2 - 3 - 4 - 6. 8. 10. 15 * 20. 30. | 40. 5 °- 75 - IOO. 'Value of it 7.41 9.33 10.68 11.76 13.46 14.83 rs.ge l8.26 20.11 23.02 25.33 27.28 31.26 34 - 3 ® Mr. Dredge suggests, also in Indian Professional Papers, the following formula : M Q = 1300 (3) in which L is the length of the watershed, and M the area in square miles. Our formula, modified as follows, gives an approximate flood volume per square mile, in cubic feet per second : Q = 200 (M)t M (4) TABLE OF FLOOD VOLUMES. 67 in which M is the area of the given watershed in square miles. 44. Table of Flood Volumes. — Upon the average New England and Appalachian basins, maximum floods may be anticipated with rates of flow, as per the following- table: (See § 386 , page 381 , Waste-Weirs.) TABLE No. 9 . Flood Volumes from given Watersheds. Area of Water- shed. M. Sq. Miles. °-5 1 2 3 4 6 8 io 15 20 2 5 30 40 5o 75 IOO 200 3 °° 400 5°0 600 800 IOOO 1500 2000 3000 4000 5000 Flood Discharge for Whole Area, 4 Q = 2 O Dec. in. in. in. in. in. in. in. in. in. in. in. in. Mean 102.8 71. 1 158.9 117.2 80.5 44.8 19.0 24.6 26.6 3°-4 78.9 97.0 Minimum. 17.7 59 -o ioq.o 93-2 46.7 17.6 7-3 3-4 3-3 11. 2 40.5 65.6 Maximum ........ 186.6 103.9 209.1 158.4 100.3 71.2 3 r -4 53-8 39.8 56.3 1 10.2 140.8 Ratio of monthly mean . , ........ 1.448 1. 001 2.238 1.651 .636 .267 •347 •375 .428 1.112 1.367 TABLE No. 16. Summary of Volume of Flow of Rainfall from the Cochituate Basin (in cubic feet per minute per square mile). G ci Feb. Mar. Apr. May. June. July. Aug. «T C /2 Oct. Nov. Dec. cu.ft. 99-17 37-99 245.12 cu./t. 150.42 58.29 301.90 cu./t. 174.76 91.60 242.52 cu.ft. 169.80 70.44 369.40 cu.ft. 131.80 67.14 321. II cu.ft. 44.27 18.28 85-49 cu.ft. 45-27 21-34 154.57 cu.ft. 49-15 21.34 109.29 cu.ft. 42.84 4.30 99.48 cu.ft. 62.45 36.43 123-34 cu.ft. 75.90 47-32 105-39 cu.ft. 78.94 40.07 164.98 Maximum Ratio of monthly 1.058 1.605 1.865 1.812 1.406 .472 fO 00 •524 •457 .666 .809 .842 TABLE No. 17. Summary of Volume of Flow of Rainfall from the Croton Basin (in cubic feet per minute per square mile). Jan. Feb. s Apr. May. June. July. Aug. Sept. Oct. Nov. d 0 Mean cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft . 91.48 147.69 177.02 132.63 164.49ln5.12 48.37 70.22 85-99 81.08 124.92 106.23 Minimum 48.08 40.65 79-°5 87.43 108.25 34-09 10.46 I 3 - 12 12.91 18.05 61.41 72.08 Maximum 127.71 293.01 25.709 188.95 to VO 00 224-33 81.76 202.19 275-95 141-14 201.30 146.24 Ratio of monthly mean .816 1-347 4-579 1.183 4-467 1.027 •434 .627 .767 .723 1.114 .948 SECTIONS OF CROTON NEW AQUEDUCT, I t MINIMUM, MEAN, AND FLOOD FLOW OF STREAMS. 75 TAB LE No. 1 8. Summary of Volume of Flow of Rainfall from the Croton West-Branch Basin (in cubic feet per minute per square mile). fl & Feb. Ih *2 cL < >> s [ June. ' >> 3 Aug. Sept. Oct Nov. Dec. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft. cu.ft- cu.ft. cu.ft. cu.ft. Mean 158.95 185.19 290.56 272.60 161.60 103.8 6 40.02 103.12 x 47-59 96.26 107.85 164.07 Minimum ... 35.08 47.16 203.58 146.04 26.19 45.18 19.26 9.06 5 -i6 27.48 5-92 50.88 Maximum 347.88 378.90 39°- 8 3 463.98 394.92 202.02 85.56 281.04 477-22 277.26 203.28 299.16 Ratio of monthly mean. 1. 04 1 1-213 1.904 1.786 1.059 .680 .262 .676 .967 .631 .707 I -°75 53. Minimum, Mean, and Flood Flow of Streams. — An analysis of the published records of volumes of water flowing in the streams in all the seasons has led to the fol- lowing approximate estimate of volumes of flow in the aver- age Atlantic coast basins : The minimum refers to a fifteen days’ period of least summer flow. The mean refers to a one hundred and twenty days’ period, covering usually July, August, September, and October, beginning sometimes earlier, in June, and ending sometimes later, in November. The maximum refers to flood volumes. TABLE No. 19. Estimates of Minimum, Mean, and Maximum Flow of Streams. Min. in cu. ft. per sec. per sq. mi. Mean in cu. ft. per sec. per sq. mi. Max. in cu ft. per sec. per sq. mi. Area of watershed, 1 sq. mi. 00 O I. OO 200 tt tt a IO it .1 .99 136 it it tt 2 5 tt .11 .98 117 5 ° .14 •97 104 it it it 100 tt .18 •95 93 tt it it 250 it • 2 5 .90 80 it u a 5°° a • 3 ° .87 71 a a tt 1000 a •35 .82 6 3 it a a 1500 a .38 .80 59 a a a 2000 a .41 •79 56 76 FLOW OF STREAMS. This table refers to streams of average natural pondage and retentiveness of soil, but excludes effects of artificial storage. The fluctuations of streams will be greater than indicated by the table when prevailing slopes are steep and rocks impervious, and less in rolling country with pervious soils. 54. Ratios of Monthly Flow in Streams. — A care- ful analysis of the published records of monthly flow of the average Atlantic coast streams leads to the following ap- proximate estimate of the ratio of the monthly mean rain- fall that flows down the streams in each given month of the year, in which due consideration of the evaporation from soils and foliage in very dry seasons has not been neglected. TABLE No. 20. Monthly Ratios of Flow of Streams. Jan. Feb. March. April. May. June. July- fch D < Sept. Oct. Nov. (5 Q Ratio of flow . 1.65 1-50 1.65 i -45 •85 •75 •35 •25 .30 •45 1.20 1.60 Here unity equals the mean monthly flow, or one-twelfth the mean annual flow. To compute, approximately, the inches depth of rain flowing in the streams each month, one-twelftli the mean annual rain, at the given locality, may be multiplied by the ratios in the following table. For illustration, a mean annual rain of 40 inches depth, giving 3.333 inches mean monthly depth, is assumed, and the available flow of stream expressed in inches depth of rain is added after the ratios. MEAN ANNUAL FLOW OF STREAMS. 77 TABLE No. 21. Ratios of Mean Monthly Rain, and Inches of Rain Flowing. each Month. Jan. Feb. Mar. Apr. May. j June, j 1 July. Aug. Sept. O O 1 Dec. Ratios of mean monthly rain .825 •75 0 .825 .725 ■425 •375 •i75 .125 .150 .225 • 600 .800 inches of rain flowing 2.75 2.50 2-75 2.41 1.41 1.25 o -59 O.4I O.5O 0.75 2.00 2.66 Eight - tenths 0.60 X.60 of same . . . 2.20 2.00 2.20 *•93 I,I 3 1. 00 0.47 o-33 O.4O 2.13 For low-cycle years, use eiglit-tentlis (§ 47) the available monthly depth of rain flowing. 55 . Mean Annual Flow of Streams. — When month- ly data of the flow of any given stream is not obtainable, it may ordinarily be taken upon average drainage areas, for an annual flow, as equal to fifty per cent, of the annual rainfall. Or, for different surfaces, its ratio of the annual rain, including floods and flow of springs, is more approximately as follows : From mountain slopes, or steep rocky hills 8o to .90 Wooded, swampy lands 60 to .80 Undulating pasture and woodland 50 to .70 Flat cultivated lands and prairie 45 to .60 Since stations for meteorological observations are now established in or near almost all the populous neighbor- hoods, and some of the stations have already been estab- lished more than a quarter of a century, it is easier to obtain data relating to rainfall than to the flow of streams. In fact, the required data relating to a given stream is rarely obtainable, and the estimates relating to the capacity and 78 FLOW OF STREAMS. reliability of the stream to furnish a given water-supply must necessarily be quite speculative. 56. Estimates of Flow of Streams. — In such case, an estimate of the capacity of a stream to deliver into a reservoir, conduit, or pump-well is computed according to some scheme suggested by extended observations and study of streams and their watersheds, and long experience in the construction of water supplies. The first reconnoissance of a given watershed by an ex- pert in hydrology will ordinarily enable him to judge veiy closely of its capacity to yield an available and suitable water supply ; for his comprehension at once grasps its geological structure, its physical features and its usual meteorological phenomena, and his educated judgment supplies the necessary data, as it were, instinctively. If the estimate of flow of a stream must be worked up from a survey of the watershed area and the mean annual rainfall, as the principal data, then recourse may be had to the data and estimates given above, relating to the question, for average upland basins of one hundred or less square miles area. In illustration, let us assume a basin of one square mile area, having a forty-inch average annual rainfall, and then proceed with a computation. This is a convenient unit of area upon which to base computations for larger areas. The ratios of the three-year low rain cycles gives their mean rainfall as about eight-tenths of the general mean rainfall. We assume it to be eighty per cent. The mean annual flow of the stream we assume to be fifty per cent, of the annual rainfall. Eight-tenths of fifty per cent, gives forty per cent, of the annual rainfall as the annual available flow of the stream, and forty per cent, of the forty inches rainfall gives an equivalent of sixteen inches of rainfall ESTIMATES OF FLOW OF STREAMS. 79 flowing down tlie stream annually. The monthly average flow is then taken as one-twelfth of sixteen, or one and one- third inches. Our estimated monthly percentage of mean flow, as given above (§ 54), is sometimes much in excess and sometimes less than the monthly average. Flows less than the mean are to be compensated for by a proportion- ate increase of storage above the mean storage required. The monthly computations are as follows : 40 inches x 50 per cent, x .8 Monthly mean = 12 months = 1333 inches average available rain monthly. This average mul- tiplied by the respective ratios of flow in each month gives the inches depth of available rain flowing in the respective months, thus : January.. . . Mean Monthly Rainfall. 1-333 X Respective Ratios. I.65 Inches Depth op Available Rain Flowing eac* Month. 2.20 February . . . (t X 1-50 = 2.00 March i< X 1.65 = 2.20 April li X i -45 = i -93 May M X .85 = 113 June ii X •75 = I. OO July a X •35 = •47 August u X •25 = •33 September. . u X •30 = .40 October .... it X •45 = .60 November. . « X 1.20 - 1.60 December . . <« X 1.60 — 2.14 Again, uniting the constants, we have .8 x .50 12 ~ 0333 which, multiplied by the respective ratios of monthly flow, thus : Jan., .0333 x 1.65 = .055, etc., gives directly the mean ratio of the low cycle annual rainfall that is available in the stream each month. 80 FLOW OF STREAMS. F LOW IK Cu. F T. PFTS Minute per Sq. Ml in each Month. Jan . 40 inches X •055 2.20 inches depth = 116.60 Feb (( X .050 = 2.00 it — 106.00 March. . U X •055 2.20 ii = ir6.6o April . . ii X .0483 = i -93 it = 102.29 May. . . . ii X .0283 = 1. 13 it — 59-89 June.. .. it X .025 — I. OO ii = 53 -oo July.... a X .012 = •47 <( - 24.91 Aug.. . . a X .0083 = •33 It 17.49 Sept. . . . <( X .OIO = .40 a 21.20 Oct a X .015 = .60 tt : - 31.80 Nov. . . . it X .040 = 1.60 ft = 84.80 Dec u X ■0533 = 2.14 a = 113.42 Total, 16.00 inches. Mean, 70.67 cu. ft 57. Ordinary Flow of Streams. — Mr. Leslie has proposed* an arbitrary rule for computing the “average summer discharge” or “ordinary” flow of a stream, from the daily gaugings, as follows : “ Range the discharges as observed daily in their order of magnitude. “Divide the list thus arranged into an upper quarter, a middle half, and a lower quarter. “The discharges in the upper quarter of the list are to be considered as floods , and in the lower quarter as minimum flows. “For each of the gaugings exceeding the average of the middle half, including flood gaugings, substitute the average of the middle half of the list, and take the mean of the whole list, as thus modified, for the ordinary or average discharge , exclusive of flood- waters.” This rule applied to a number of examples of actual measurements of streams in hilly English districts gave computed ordinary discharges ranging from one-fourth to * Minutes of Proceedings of Institution of Civil Engineers, Yol. X, p 327 . TABLES OF FLOW. 81 one-third of the measured mean discharge , including floods. The ordinary flow of New England streams is, at an average, equivalent to about one million gallons per day per square mile of drainage area, which expressed in cubic feet, .equals about ninety -two cubic feet per minute per square mile. The above computation for the average flow in low cycle years gives a little less than eight-tenths of this amount, or seventy-one cubic feet per minute per square mile as the average flow throughout the year, and a little less than one- fourtli this amount as the minimum monthly flow.* 58. Tables of Flow Equivalent to Given Depths of Rain. — To facilitate calculations, tables giving the equivalents of various depths of monthly and annual rain- falls, in even continuous flow, in cubic feet per minute per acre, and per square mile, are here inserted. Greater or less numbers than those given in Tables 22 and 28 may be found by addition, or by moving the decimal point ; thus, from Table 22, for 40.362 inches depth, take Depth, 30 inches = 1590.204 cu. ft. IO 66 — S3°.°68 66 •3 66 = I S -9° 2 66 .06 66 = 3.180 66 .002 66 : : .106 66 40.362 inches = 2139.460 cu. ft. To reduce the flows in the two tables to equivalent vol- umes of flow for like depths of rain in ohe day, divide the flows in Table 22 by 30.4369 (log. = 1.483400), and divide the flows in Table 23 by 365.2417 (log. = 2.562581). * Some useful data relating to the flow of certain British and Continental streams may be found in Beardmore’s “ Manual of Hydrology,” p. 149 (Lon- don, 1862). 82 FLOW OF STREAMS. TABLE No. 2 2. Equivalent Volumes of Flow, for given Depths of Rain in One Month.* Depths of Rain in One Month. Equivalent Flow in Cubic Feet per Minute per Acre. Equivalent Flow in Cu- bic Feet per Minute per Square Mile. Equivalent Flow in Cu- bic Feet per Month per Square Mile. Inches . .OI .00083 •530 23*232 .02 .00166 1.060 46,464 •03 .00248 I - 59 ° 69,696 .04 .00331 2.120 92,928 •°5 .00414 2.650 1 16, 160 .06 .00497 3 - i8 ° 139*392 .07 .00580 3 - 7 io 162,624 .08 .00662 4.240 185,856 .09 .00745 4.770 209,088 .1 .00828 5-3007 232,320 .2 .01656 10.6014 464,640 •3 .02484 15.9020 * 696,960 •4 •° 33 12 21.2027 929,280 •5 .04140 26.5034 1, 161,600 .6 .04968 31.8041 1,393,920 •7 .05796 37.1048 1,626,240 .8 .06624 42.4054 1,858.560 •9 • 0745 2 47.7061 2,090,880 1.0 .0828 53.0068 2*323*200 2 .1656 106.0136 4,646,400 3 .2484 159.0204 6,969,600 4 •3312 212.0272 9,292,800 5 .4140 265.0340 11,616,000 6 .4968 318.0408 13*939*200 7 .5796 371.0476 16,262,400 8 .6624 424.0544 18,585,600 9 •7452 477.0612 20,908,800 10 .828 530.068 23,232,000 20 1.656 1060.136 46,464,000 3 ° 2.484 1590.204 69,696,000 * One month is taken equal to 30.4869 days. TABLES OF FLOW. 83 TABLE No. 2 3. Equivalent Volume of Flow, for given Depths of Rain in One Year.* Depths of Rain in One Year. Equivalent Flow in Cubic Feet per Minute per Acre. Equivalent Flow in Cu- bic Feet per Minute per Square Mile. Equivalent Flow in Cu- bic Feet per Year per Square Mile. Inches * .OI .000069 .0442 23,232 .02 .000x38 .0883 46,464 •°3 .000207 •1325 69,696 .04 .000276 .1767 92,928 .05 .000345 .2209 x 16, 160 .06 .000414 .2650 I 39 , 39 2 .07 .000483 .3092 162,624 .08 .000552 •3534 185,856 .09 .000621 •3976 209,088 .1 .00069 .4417 232,320 .2 .00138 .8834 464,640 •3 .00207 I- 325 2 696,960 •4 .00276 1.7669 929,280 •5 •00345 2.2086 1, 161,600 .6 .00414 2.6503 I > 393 > 9 2 ° •7 .00483 3.0921 1,626,240 .8 .00552 3-5338 ^858,560 •9 .00621 3-9755 2,090,880 1.0 .0069 4.4172 2,323,200 2 .0138 8.8345 4,646,400 3 .0207 13-2517 6,969,600 4 .0276 17.6689 9,292,800 5 •0345 22.0862 1 1,616,000 6 .0414 26.5034 I 3 > 939 ? 2 oo 7 .0483 30.9206 16,262,400 8 •° 55 2 35-3379 18,585,600 9 .0621 39 - 755 1 20,908,800 10 .069 44.1723 23,232,000 20 .138 88.3447 46,464,000 30 .207 132.517° 69,696,000 40 .276 176.6894 92,928,000 5 ° •345 220.8617 1 16, 160,000 60 .414 265.0340 I 39>39 2 ,°oo * One year is taken, equal to 365 days, 5 hours, 49 minutes. 83a FLOW OF STREAMS, TABLE No. 23 a. Statistics of Flow of Sudbury River, Mass. 1875 to 1894. Area of Watershed 75.2 Square Miles. Mean. Min. Max. Rainfall, inches per year, (74 years), Monthly flow, cubic feet per second per square mile, Percentage of yearly rain flowing, Inches of rain flowing, yearly (74 years), Minimum flow in any week, cubic feet per second per sq. mile, Maximum flow in any day, do. do. do. Rate of flow in August, September, and October, cubic feet, per second per square mile, Annual evaporation from water surface, inches depth, Maximum evaporation in any month, inches depth, Millions of gallons, per square mile per day, 47.00 1-637 48.23 22.67 536 20 058 27.20 .068 3i-9 11. 19 .036 .068 34-05 -044 do. do. do. in May, do. do. do. in June, . do. do. do. in July, do. do. do. in August, do. do. do. in September, do. do. do. in October, do. do. do. in November, 1. 174 •5H .488 • x 75 .185 .062 .289 .055 .247 .044 •503 .071 .859 •175 67.72 7.448 62.2 35-75 43.00 3-515 43-63 7-50 4.814 2.883 ^338 •634 .476 1. 155 2.272 2758 TABLE No. 23b. Percentage of Rainfall flowing from the Sudbury Basin. Year. January. February. March. April. May. June. July. August. September. October. November. December. 1875 7.60 76.54 76-52 162.94 59-52 24.05 16.05 12.77 10.44 23.75 46.54 110.74 1876 62.68 54.20 106.47 135-41 73-5 1 18.77 3-57 42.03 6.89 18.61 32-58 22.35 1877 36.50 206.90 102.74 120.29 67.04 42.52 12.20 5-87 3 1 -89 13-24 42.17 264 -37 1878 57-3 2 66 . 50 x 33-42 48.48 250.15 22.48 7-7 x 12.22 21.46 x 4-35 41.60 89.01 1879 50.40 77-37 80.86 II4.06 125.84 18.82 7.14 10.83 12.94 x 5 -57 13.24 18.99 l88o 57-43 76.82 75.80 66.62 51 .22 X 4-52 5 • x 4 5-42 8.86 4-97 20.35 11 -33 Mean 45-3 2 93.06 95-97 IO7.96 106.21 23.58 8.64 14.86 15-41 15.08 32.75 86. 13 Minimum 7 60 54.20 75.80 48.48 51.22 14.52 3-57 5-42 6.89 4-97 13-24 ”•33 Maximum Ratio of monthly 62.68 206.90 133-42 162.94 260. 15 42.52 16.05 42.03,31.89 23-75 46.54 26437 mean 0.84 x -73 1.79 2.02 1.98 0-44 0. 16 0.28 0.29 0.2S 0.61 1 60 TABLES OF FLOW, 83 1 TABLE No. 23c. Run-off of the Sudbury River Watershed,* 1875 to 1899. (Area of Watershed 75.2 Square Miles and 6.5 per cent. Water Surface in 1899.) CUBIC FEET PER SECOND PER SQUARE MILE. Year. January. February. March. April. May. June. July, August. September. October. November. | December. Av. Mo. 1875 0.159 2 - 3!5 2.482 CO 1.838 1.346 O.497 0.612 0.321 I .OOO 2.015 0.903 1.504 I876 0-995 2.116 6.862 5-°94 I.761 o -343 0.283 O.627 O.285 0.361 1.683 0.702 1-756 1877 I. OI9 1-469 7 '448 3-703 2.153 0.924 0.312 O.187 0.092 O.Q 77 2.193 I -995 1.878 1878 2.800 3-814 5.426 2.516 2.158 0.782 0.199 0.736 0.249 0-799 2.619 4.916 2.246 1879 1.083 2.647 3.605 4.821 1.723 0.640 O.243 0.6ll 0.218 0.109 0.318 0.716 1-383 1880 1-733 2.765 2. 126 1.808 O. 796 0.271 0.273 O.184 0.124 0.157 0.318 0.271 0.895 l88l 0. 642 2.392 6.195 2.392 1-493 2.070 O.428 0.229 0.305 O.287 0.611 I - I 99 1515 l882 1.920 3.718 4 - 39 2 1.342 1.998 0.818 0.133 0.086 O.474 0.463 0-324 0.487 *•334 1883 0.518 1.598 2.492 2.088 1.450 0.464 O.I78 0.122 O.I4I 0.288 0.317 0.299 1.824 1884 1 - 54 ° 4-397 5-857 4 - 4*5 i -594 0.644 0.346 0-397 0.068 0.129 0.271 I - 43 I x -747 1885 I.QIO 2.095 2-433 2.808 2.067 0.659 O.O96 O.372 O.187 O.5I9 1.822 1. 816 *•393 l886 2.260 7.428 3-185 3- 01 3 1.114 0.314 0.179 O.I46 0.182 0.225 1. 04 1 1-578 1.682 1887 4.006 . 4-377 4-437 4-053 1.561 0.640 O. I78 0 - 33 1 O.I72 0.294 0.570 o -995 1-785 1888 I.629 3. 011 5.009 4-°93 2.526 0.652 O. l82 0-587 I.786 3-093 4.267 4.708 2.626 I889 4-305 1.850 2.071 2. 182 1.361 1. on O.980 2.216 I.274 I.9O3 3-003 3-467 2.140 I89O 1. 94 1 2.366 5-636 2.900 2.114 0.878 O. l66 0.204 O.708 3-515 1.879 I- 54 X 1.989 189I 4.669 5-393 6.891 3 - 7°9 0.901 0.639 O.23I 0.252 O.3I4 0.325 0.472 O.842 2.034 1892 2.893 i -459 3.025 1.348 1.947 0.662 c- 33 1 o -433 0-355 O.I95 1.079 0.750 1.209 1893 O.67I 2.386 5.021 3.288 4.461 0.680 0.244 0.280 O.167 0-343 0-493 1.232 1.604 1894 I.O72 1 533 3-463 2-538 1.299 0.648 0.249 0.324 0.231 o -579 1.293 I .108 1. 192 1895 1.600 0.837 3-728 3.892 0.984 0.269 0-357 0-354 0.138 2-134 4.296 2-757 1.782 I896 1.677 4.140 5-933 2.312 0-557 0.617 o-i 47 0.088 0.600 0.916 1 .020 1.017 1-576 1897 I - 3°7 1.651 3.968 2-344 1.416 1.488 1. 018 0.914 0.282 0.145 1.407 2-451 t -533 I898 2-535 4.676 4.029 2.831 1.927 0.820 o .357 1. 712 0.571 i -795 3-073 2.783 2.244 1899 3 - 54 i 2.137 6.507 3.900 0.790 0.102 0.030 -•054 O.I45 0.179 0-474 0.340 1.506 Average i -937 2.904 4.489 3.124 1.680 o -735 0.305 0.478 0.376 0.829 1.474 1.612 1-655 Max. 4.669 7.428 7.448 5-094 4.461 2.070 1. 018 2.216 I.786 3-515 4.296 4.916 2.626 Min. 0.159 0.837 2.071 1.342 0-557 O. 102 0.030 0. 0.068 0.109 0.271 0.271 0.824 * Boston, F. P. Stearns, Chief Engineer Metropolitan Water Board. The Water surfaces were increased from time to time, from 1.9 per cent, in 1875 to 6.5 per cent, in 1899. CHAPTER Y. STORAGE AND EVAPORATION OF WATER STORAGE. 59. Artificial Storage. — The fluctuations of tlie rain- fall, flow of streams, and consumption of water in the differ- ent seasons of the year, require almost invariably that, for gravitation and hydraulic power pumping supplies , there shall be artificial storage of the surplus waters of the sea- sons of maximum flow, to provide for the draught during the seasons of minimum flow. A grand exception to this general rule is that of the natural storage of the chain of great lakes that equalizes the flow of the St. Laurence River, which furnishes the domestic water supply of the City of Montreal and the hydraulic power to pump the same to the reservoir on the mountain. When the mean annual consumption, whether for do- mestic use, or for power and domestic use combined is nearly equal to the mean annual flow of the supplying watershed, the question of ample storage becomes of su- preme importance. The cliief river basins of Maine present remarkable examples of natural storage facilities, since they have from six to thirteen per cent., respectively, of their large watershed areas in pond and lake surfaces. 60. Losses Incident to Storage. — There are losses incident to artificial storage that must not be overlooked ; for instance, the percolation into the earth and through the embankment, evaporation from the reservoir surface and from the saturated borders, and in some instances constant draught of the share of riparian owners. EMBANKMENT: IMPOUNDING AND DISTRIBUTING RESERVOIR, NORWICH, CONN. SUDBURY DAM, BOSTON, W. W„ Page 84^ RIGHTS OF RIPARIAN OWNERS. 85 61. Sub-strata of the Storage Basin. — The structure of the impounding basin, especially when the water is to fill it to great height above the old bed, is to be minutely examined, as the water at its new level may cover the edges of porous strata cropping out above the channel, or may find access to fissured rocks, either of which may lead the storage by subterranean paths along the valley and deliver it, possibly, a long distance down the stream, or in a mul- titude of springs beyond the impounding dam. If the water carries but little sediment of a silting nature, this trouble will be difficult to remedy, and liable to be serious- ly chronic. 62 . Percolation from Storage Basins.— Percolation through the retaining embankment is a result of slighted or unintelligent construction, and will be discussed when con- structive features are hereafter considered. (See Reservoir Embankments.) 63. Rights of Riparian Owners. — The rights of riparian owners, ancient as the riparian settlements, to the use of the water that flows, and its most favored piscatory produce, is often as a thorn in the impounder’s side. What are those rights ? The Courts and Legislatures of the man- ufacturing States have wrestled with this question, their judges have grown hoary while they pondered it, and their attorneys have prospered, and yet who shall say what riparian rights shall be, until the Court has considered all anew. Beloe mentions* that it is a “common (British) rule in the manufacturing districts to deduct one-sixth the average rainfall for loss by floods, in addition to the absorption and evaporation, and then allow one-third of the remainder to * Beloe on Reservoirs, p. 12. London, 1872. 86 STORAGE AND EVAPORATION OF WATER. the riparian owners, leaving two-thirds to the impounders. In some instances this is varied to the proportion of one- quarter to the former and three-quarters to the latter.” The question can only be settled equitably upon the basis of daily gaugings of How, through a long series of years. A theoretical consideration involves a thorough investigation of its geological, physical, and meteorological features. There is no more constancy in natural flow at any season than in the density of the thermometer’s mercury. The flow increases as the storms are gathered into the chan- nel, it decreases when the bow has appeared in the heavens ; it increases when the moist clouds sweep low iu the valleys, it decreases under the noonday sun ; it increases when the shadows of evening fall across the banks, it decreases when the sharp frosts congeal the streams among the hill s. 64. Periodical Classification of Riparian Rights. — The riparian rights subject to curtailment by storage might be classified by periods not greater than monthly, though this is rarely desirable for either party in interest, but they should be based upon the most reliable statistics of monthly rainfall, evaporation, and flow, as analyzed and applied with disciplined judgment to the particular locality in question. 65. Compensations. — In the absence of local statistics of flow, it may become necessary, in settling questions of riparian rights, or adjusting compensation therefor, to esti- mate the periodic flow of a stream by some such method as is suggested above iu the general discussion upon the flow of streams, after which it remains for the Court to fix the proportion of the flow that the impounders may manipulate for their own convenience in the successive seasons, and the proportion that is to be passed down the stream regularly or periodically. EVAPORATION PHENOMENA. 87 EVAPORATION. 66. Loss from Reservoir by Evaporation.— Losses by evaporations from the surfaces of shallow storage reser- voirs, lakes and ponds are, in many localities, so great in the summer and autumn that their areas are omitted in compu- tations of water derivable from their watersheds. This is a safe practice in dry, warm climates, in which the evapora- tions from shallow ponds may nearly or quite equal the volume of rain that falls directly into the ponds. Marshy margins of ponds are profligate dispensers of vapor to the atmosphere, usually exceeding in this respect the water surfaces themselves. 67. Evaporation Phenomena. — The measure of evaporation from a water surface is the resultant of forces of vaporiza tion acting upon the water and upon the moisture in the air near the water. The constituents of water may, with certain changes of temperature, change their state of existence from that of liquid to vapor, vapor to liquid or liquid to solid, and solid to vapor. Each new increment of heat entering the particles of mist in the atmosphere or liquid in the lake increases their gaseous activities and diffusive powers, and the rapidities of vaporizations of liquid, snow, ice, and the moisture of the air depends upon their respective absorption rates of heat. The volume of vapor diffused from water surfaces into the air greatly exceeds, usually, the diffusion from the adjacent air and condensation into the water, not including the depositions of showers. This difference, the net loss of the water, is the rate or volume of evaporation from the water. The resultant varies in weight with the difference between the dynamical force of the vapor in the water and the like force of the vapor in the air, due to their respec- 88 STORAGE AND EVAPORATION OF WATER. tive temperatures, and further to the relative dryness and motion of the receptive air sweeping across the water. The atmosphere lias, however, for each given tempera- ture a limit of power to retain vapor. When winds blow briskly across a reservoir, large volumes of un saturated air may be presented to receive the diffused vapor from the water, while the wave agitation aids at the same time the escape of vapor from the ruffled water surface, giving a large rate of net evaporation. 68. Evaporation from Water. — Mr. Fitzgerald’s careful experimental measures* of evaporation from water surfaces at Chestnut Hill reservoir in Boston, was as follows : TABLE No. 2 4. Experimental and Estimated Monthly Evaporation. £ Feb. Mar. 1 1 April. May. June. July. Aug. Sept. Oct. > z Dec. Total. Measured evaporation in inches o. 90 1.20 1.80 3.10 4.61 5.86 6.28 5-49 4.09 2.95 1.63 1.20 39 - 11 Theoretical mean evapor- 3.82 ation in inches 0.98 I. OI i -45 2.39 5-34 6.21 5-97 4.S6 3-47 2.24 i- 3 8 39.12 Percentage of theoretical mean per cent 2.51 2.58 3-71 6.11 9.76 13-65 15.87 15.26 12.42 8.87 5-73 3-53 100.00 Theoretical mean daily, inches .0316 .0361 .0467 .0796 .1232 .1980 .2003 .1926 .1620 . III9 .O747 •0445 39.12 Mr. Fitzgerald’s maximum recorded daily evaporation from the reservoir surface was on June 23, 1885, when from tanks Nos. 1, 2, and 3, the evaporations were 0.57, 0.64, and 0.58 inches respectively, the mean temperatures of the waters being nearly 70° Fah. Evaporation, Trans. Am. Soc. Civ. Engrs., Vol. XV., p. 581. EVAPORATION FROM EARTH. 89 TABLE No. 24. Evaporation from Water at Emdrup, Denmark. N. Lat. 55°4i" ; E. Long i2 0 34" from Greenwich. Year. Jan. Feb. £ Apr. May. June. July. Aug. Sept. Oct. > 0 Dec. Total. In. In. In. In. In. In. In. In. In. In. In. In. In. 1849 1. 1 o -3 1.8 2.5 4.1 5-8 4-7 4.0 2.6 1. 1 0.9 0.6 2 9-5 1850 1. 1 o -3 1.2 1-7 4-5 5-6 4.8 4.8 2.4 1.6 0.9 0.2 29.1 1851 o-S 0.4 O.7 i -7 4.2 4.8 5-7 5 -i 2.7 >•5 0.6 o -5 28.4 1852 O.7 °-5 0.8 2.4 3.8 4.6 6.4 4-5 2.7 i -7 0.8 o-5 29.4 1853 0.5 0.1 0.7 1.0 4 * 1 6.2 5 -i 4.2 2.8 1. 1 0.6 o -5 26.9 1854 o -5 0.9 0.9 3-2 3-3 4-5 5-2 4-3 2.6 1.2 °*7 0.6 27.9 1855 1.0 1. 1 o -5 1.2 2.6 4.1 4-7 4.1 2.8 1.4 °-9 0.7 25-1 1856 o -5 o -5 1.2 2.1 2.8 4.6 4-3 4.0 2.0 0.9 0.6 o-5 24.0 1857 0.7 0.6 0.6 i -4 4 - 1 6.6 5-9 4-3 3-2 x -4 0.7 0.4 29.9 1858 0.4 0.7 1.2 3 -i 5-1 6.1 4.9 5-6 2.8 1.6 0.7 0.4 30.6 1859 o -3 o-5 0.7 1.9 4-3 5-8 5-3 3.8 1.8 1.0 0.7 o -3 26.4 Mean . . 0.7 0.5 o-9 2.0 3-9 5-3 5-2 4.4 2.6 i-3 0.7 o -5 27.9 Ratio . . •3 QI .215 •387 .860 • I * 59 2 2.323 2.237 1.892 1.118 •559 .301 .215 Mean Evaporation from Short Grass, 1852 to 1859 inclusive. Mean.. | 0.7 | 0.8 | 1.2 | 2.6 | 4.1 | 5.5 | 5.2 | 4.7 | 2.8 | 1.3 | 0.7 | 0.5 | 30.1 Mean Evaporation from Long Grass, 1849 t0 *856 inclusive. Mean..) 0.9 | 0.6 | 1.4 | 2.6 | 4.7 | 6.7 | 9.3 | 7.9 | 5.2 | 2.9 | 1.3 | 0.5 | 44.0 Mean Rainfall at same Station, 1848 to 1859 inclusive. Mean..! 1.5 I 1.7 l 1.0 I 1.6 I 1.5 I 2.2 I 2.4 I 2.4 I 2.0 I 2.3 I 1.8 TABLE No. 2 5. 69. Evaporation from Earth. — Mean Evaporation from Earth, at Bolton Le Moors,* Lancashire, Eng., 1844 to 1853, INCLUSIVE. Lat. 53°3o" N. ; Height above the Sea, 320 Feet. c c 3 Feb. c 3 S Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. Total. Mean . . Ratio. . . O.64 .299 o-95 •444 1.59 •739 2 59 1. 212 4-38 2.049 3- 8 4 1.796 4.02 I.887 3.06 I -43 I 2.02 •945 1.28 •599 0.8l •379 O.47 .220 25-65 Mean Rainfall at same Station, 1844 to 1853 inclusive. Mean.. I 4.63 | 4.03 j 2.25 | 2.22 | 2.23 1 4 07 | 4.32 | 4.77 | 3.79 | 5.07 | 4.64 | 3.94 | 45.96 * Beardmore’s Hydrology, p. 325. 90 STORAGE AND EVAPORATION OF WATER. Mean Evaporation from Earth, at Whitehaven, Cumberland, Eng., 1844 to 1853 inclusive. Lat. 54 30" N. ; Height above the Sea, 90 feet. Jan. Feb. Mar. a <5 May. June. July. Aug. 1 Sept. 1 Oct. Nov. Dec. Total. ' 1 Mean. Ratio . . 0.95 •390 I. OI •415 i-77 .727 2.71 1.113 4.II I.689 4.25 1.746 4.13 1.697 3*29 1-352 2.96 I.2l6 I.76 •723 1-25 •513 1.02 .419 29.21 Mean Rainfall. at same Station, 1844 to 1853 inclusive. Mean.. | 5.1 | 3.4 | 2.5 j 2.2 | 1.9 | 3-* [ 4-3 | 4-3 | 3-i 1 5-3 : 4-5 [ 3-8 | 43-5 70. Examples of Evaporation.— Charles Greaves, Esq., conducted a series of experiments upon percolation and evaporation, at Lee Bridge, in England, continuously from 1860 to 1873, and lias given the results * to the Insti- tution of Civil Engineers. The experiments were on a large scale, and the very complete record is apparently worthy of full confidence. The evaporation boxes were one yard square at the sur- face and one yard deep. Those for earth were sunk nearly hush in the ground, and that for water floated in the river Lee. The mean annual rainfall during the time was 27.7 inches. The annual evaporations from soil were, mini- mum 12.067 inches ; maximum 25.141 inches ; and mean 19.534 inches: — from sand , minimum 1.425 inches; maxi- mum 9.102 inches; and mean 4.648 inches: — from water , minimum 17.332 inches ; maximum 26.933 inches ; and mean 22.2 inches. Some experimental evaporators were constructed at Dijon on the Burgundy canal, and are described in Annales des Ponts et Cliausses. They are masonry tanks lined with zinc, eight feet square and one and one-third feet deep, * Trans. Inst. Civil Engineers, 1876, Vol. XLV, p. 33. RATIOS OF EVAPORATION. 91 and are sunk in the ground. From 1846 to 1852, there was a mean annual evaporation of 26.1 inches from their water surfaces against a rainfall of 26.9 inches. At the same time a. small evaporator, one foot square, placed near the larger, gave results fifty per cent, greater. Observations of evaporation from a water surface at the receiving reservoir in New York indicated the mean annual evaporation from 1864 to 1870 inclusive as 39.21 inches, which equaled 81 per cent, of the rainfall. On the West Branch of the Croton River, an apparatus* was arranged for the purpose of measuring the evaporation from water surface, consisting of a box four feet square and three feet deep, sunk in the earth in an exposed situation and filled with water. The mean annual evaporation was found to be 24.15 inches, or about fifty per cent, of the rainfall. The observations were made twice a day with care. The maximum annual evaporation was 28 inches. Evaporations from the surface of water in shallow tanks are variously reported as follows : At Cambridge, Mass., one year, 56.00 inches depth, 66 Salem, “ tt it 56.00 66 66 66 Syracuse, N. Y., ti It 50.20 66 66 66 Ogdensburgh, N. Y., tt tt 49-37 66 66 u Dorset, England, three “ 25.92 66 66 u Oxford, “ five “ 3 I>0 4 66 66 u Demerara, three “ 35- 12 66 66 u Bombay, five “ 82.28 66 66 71, Ratios of Evaporation. — In the eastern and mid- dle United States, the evaporation from storage reservoirs, having an average depth of at least ten feet, will rarely exceed eighty per cent, of the rainfall upon their surface * Vide paper on “ Flow of the VVest^Branch of the Croton River,” by J. Jas R. Croes. Trans. Am. Soc. Civ. Engrs., July, 1874, p 83. 92 STORAGE AND EVAPORATION OF WATER. The ratio of evaporation in each month to the monthly aver- age evaporation, or one-twelfth the annual depth, is esti- mated to be, for an average, approximately as follows : TABLE No. 2 6. Monthly Ratios of Evaporation from Reservoirs. c •—i Feb. Mar. Apr. May. June. >> Aug. Sept. Oct. Nov. Dec. Mean ratio .... • 3°° •3^8 .426 •732 1.128 I -53° I.83O 1.952 i-793 1.055 •558 .378 The following ratios of the annual evaporation from water surfaces are equivalent to the above monthly ratios, and may be used as multipliers directly into the annual evaporation to compute an equivalent depth of rain in inches upon the given surface in action. Beneath the ratios are given the equivalent depths for each month of 40 inches annual rain, assuming the annual evaporation to equal eighty per cent, of the rainfall, or 32 inches depth. TABLE No. 27. Multipliers for Equivalent Inches of Rain Evaporated. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. Total. Ratio ot annual evapora- .0265 .85 •0355 m3 .0610 .0988 3 01 •1273 4.08 . 1 525 .1625 .1495 .0880 .0465 • 0 3 x 5 Equivalent depth of rain — inches .80 1.95 4.88 5 20 4.78 2.85 1.49 1. 01 32 72 . Resultant Effect of Rain and Evaporation.— For the purpose of comparing the effects upon a reservoir replenished by rain only, let us assume the available rain- fall to be eight-tenths of 40 inches per annum, and the ratios of mean monthly rain, and the ratios of annual rain in inches depth, to be as per the following table : PRACTICAL EFFECT UPON STORAGE. 93 d P-* Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. Ratio of aver, monthly rain •75 .83 .90 I. IO 1.30 1.08 1. 12 1.20 I. OO •95 •93 .84 Ratio of .8 of annual rain. .0625 .0692 .0750 .O9I7 .1083 .0900 .0933 .IOOO .0833 .0792 •°775 .0700 Equiv. inches 2.67 2.48 ol rain ...... 2.00 2.21 2.40 2.93 3-47 2.88 2.99 3.20 2-53 2 24 Comparing, in the two last tables, and their lowest columns, the inches of gain by rainfall upon the reservoir, supposing the sides of the reservoir to be perpendicular, and the inches of loss from the same reservoir by evaporation, we note that the gain preponderates until June, then the loss preponderates until in November. 73. Practical Effect upon Storage. — Since the prac- tical value of storage is ordinarily realized between May and November, the excess of loss during that term is, practically considered, the annual deficiency from the reser- voir' chargeable to evaporation. We compute its maximum in the following table, commencing the summation in June, all the quantities being in inches depth of rain. d Feb. ' Mar. Apr. May. June. July. Aug. a m Oct. Nov. Dec. Total. ' Gain by rain- inches 2.00 2.21 2 40 2-93 3-47 2.88 2.99 3.20 2.67 2-53 2.48 2.24 32 Loss by evapo- ration — inches .80 ■85 I * I 3 1.95 3.01 -e- b 00 4-88 5.20 4.78 2.82 1.49 1. 01 32 D ifference — inches + 1.20 + i-3 6 + 127 + 0.98 +0.46 — 1.20 — I.89 — 2.00 — 2. 11 0.29 +0.99 +1.23 Max. deficiency after June — inches — 1.20 — 3-°9 -5.09 — 7.20 -7-49 —6.50 — 5-2 7 If the classification is reduced to daily periods instead of monthly, the maximum deficiency, according to the above basis, will in a majority of years exceed eight inches. 93a STORAGE AND EVAPORATION OF WATER. The following table, No. 27a, is quoted from the “Monthly Weather Review,” for September, 1888, and is by T. Russell, Asst. Prof. U. S. Signal Service. It is the result of one year’s observations at the signal stations named, the evaporations being reduced from measures taken with a Piche evaprometer. Mr. Russell says, “It is believed that these figures represent approximately, the monthly and annual evaporations that take place from the surface of ponds, rivers, reservoirs, and lakes in the vicinity of the respective Signal Service stations named.” TABLE No. 2 7 a. Computed Relative Monthly Evaporations in America. Stations and Districts. Jan. 1888. Feb. 1888. 00 00 00 Irt rt a April, 1888. May, 1888. | June, 1888. CO 00 tv. 00 00 to < Sept. 1887. Oct. 1887. Nov. 1887. CO 0 0 G i2 Months’ Evaporation. Precipitation in 1888. In. In. In. In. In. In. In. In. In. In. In. In. In. In. New England. Portland 1.0 1.2 1.8 2.6 1.8 3-3 3-8 3-9 3-4 3 ° 2-5 1.4 29.7 59-24 Manchester o.q 1.6 2.2 3-3 3-8 5 -o 4.1 3-3 2-5 2.8 2.4 1.4 33-3 46.81 Northfield 0.8 1.0 i -5 2-3 2-5 3-4 3-5 2.7 2-3 1.8 1. 1 1.0 23.9 45.89 Boston 1.2 1.6 2.2 3-4 3 -i 4-7 4.4 4.0 3-5 2-7 2.2 1.4 34-4 45.89 Nantucket 1. 1 1. 1 1.2 i -5 1.8 2.1 3-3 3-8 3-4 2.7 1.8 1.8 25.6 45-71 New Haven 1. 1 1.6 1.8 2.7 2.7 4 -i 3 7 3-8 31 3.2 2.4 1.6 31.8 60.26 New London i -5 ‘•3 i -5 2.6 2.8 4.0 3-4 3-9 3-2 3 - 1 2.4 2.1 31.8 45.61 Middle Atlantic States. Albany o.q 1.2 1.6 3-3 3-9 4-5 5 -o 4-7 3-2 3-o 2.1 1.4 34-8 44.66 New York City i.8 I.4 2.0 3-4 3-3 4.6 5 ° 5-2 4-3 4 - 1 3-3 2.2 40.6 52.95 Philadelphia i.6 2. I 2-5 4.4 4.0 5-7 5-7 5-2 4-3 4.0 3-3 2.2 45 -o 44.06 Atlantic City 1.2 1.6 i -5 2.4 1.8 3 b 2.9 3-3 2.4 1.8 1.2 *•5 25.2 44.14 Baltimore 2.0 2.2 2.8 5 -i 4-7 5-9 6.0 5 0 4.4 4-3 3-6 2.4 48.1 43-53 Washington City 1.8 i -7 2-5 4.2 3-8 6.0 5-4 4-9 4 - 1 4.2 4-5 2-5 45.6 45-05 Norfolk 1.8 1.6 2-3 3-5 3-2 4.2 4.6 3-7 3-7 2.9 2-3 1.8 35-6 56.64 South Atlantic States. Charlotte 2.6 2.6 4-3 6.4 4-5 5-8 4.0 4.0 4.6 4.0 3-6 2.6 49.0 52.61 Hatteras i.8 1.6 i.6 2-5 2.2 3 -° 3-3 4.1 3-8 3-2 2.6 1.6 3 T -3 59-73 Wilmington 2. 4 2.2 2-7 3-3 33 4-3 4-3 3 -i 3-9 3-4 2.8 2-7 38.4 55-07 Charleston 2-5 2-5 3-5 3-7 3-9 4-4 4-5 4.8 4.2 4.0 3-2 2.5 43-7 49-40 Augusta 3 *o 2.6 3-4 5-3 ^.8 5-0 4.8 4-5 5 -i 4.1 3.6 3 -i 49 3 49. 88 Savannah 3-3 2.8 4 - 1 4-7 4-3 4.6 4.2 4-7 3-4 3-9 3-5 2.8 46.0 47.06 Jacksonville 2.9 2.6 3.8 4-3 4.6 5-3 5 ° 4-7 3.8 3-9 3.0 2.1 45-7 53 - x 3 Florida Peninsula. Titusville 3-5 2.6 3-3 3-8 3-8 4-3 3-8 4-3 4.0 4.1 3.6 3-i 44.2 59-96 Cedar Keys 3-3 2.8 4.0 4.6 4-5 5-i 5-0 5-5 4-5 4.1 3-5 2.6 49-5 43- 13 Key West 3.8 3-7 3-8 4-5 4.4 4.8 5-i 5- 1 4-7 4-3 3-8 3-6 51-6 35-58 Eastern Gulf States. Atlanta 2.7 2.6 4.0 6.2 4-7 5 -o 4-5 4-7 5-8 4.6 4-2 2-5 5i-5 64.98 Mobile 2.6 2-5 2.8 3-5 3-7 4.0 4.1 4.6 4.6 4.1 3-4 2.2 42.1 75-59 Montgomery 3-5 3-3 S.I b -5 5-9 5.8 4-3 4-5 5-7 4.6 4-3 3- 1 56.6 61.39 Vicksburg 2.1 2-5 3-6 5 -i 5 7 4.8 4.0 5 -o 4-7 3-4 4.0 2.2 47.1 4S-47 New Orleans 2.8 2.8 4.1 3.8 4-2 4.1 4.1 4-3 4.4 4.6 3-7 2-5 45-4 — STORAGE AND EVAPORATION OF WATER. 935 T A BL E N o. 2 7 a. — ( Continued .) Stations and Districts. Jan. 1888. 00 CO CO -d V ta Mar. 1888. April, 1888. CO 00 CO £ s June, 1888. July, 1887. | Aug. 1887. Sept. 1887. CO CO 0 Nov. 1887. Dec. 1887. 12 months’ Evaporation. Precipitation in 1888. In. In. In. In. In. In. In. In. In. In. In. In. In. In. Western Gulf States. Fort Smith 2.2 2.7 3-5 5*3 4.4 4.6 5.6 4.6 4-7 5-9 3-9 2.2 49.6 50.97 Little Rock 2.1 2.8 3-5 5-5 4.8 4 -i 5-4 5-9 5.8 5-2 4-3 2-3 51-7 57-55 Galveston i.6 2.8 3.2 2.9 4-3 4.2 3-3 5-2 5-2 4-7 4.2 2.4 46.0 65.88 San Antonio 2.4 3-3 4 -i 3.8 4.0 4-5 6.6 5-8 5-2 5-4 4.2 3-1 52.4 40-55 Rio Grande Valley. Rio Grande City ..... 2.7 3-5 3-5 3-6 4-5 4.6 6.9 7.0 5-2 4.9 3-6 3 -i 53 - 1 22.74 Brownsville 1.8 2.6 2.9 3 -o 3-5 3-9 4-0 4.1 3-3 3.0 2.6 2-3 37 -o 32.58 Ohio Valley and Tennessee. Chattanooga 2.0 3-3 3-3 5-3 3-7 4-3 4-3 5.0 5-4 4.0 3-9 1.9 46.4 54-87 Knoxville 2.4 2.6 3-4 5 -o 3-5 4.2 4-9 5 -o 4-9 4.1 3-8 2.1 45-9 53-03 Memphis 2.1 2.3 3 - 1 5-9 5-3 4-8 4.9 5-4 5-5 4.2 4.1 2.4 50.0 46.82 Nashville 1.9 2.1 3-2 5-9 5 -o 5 - 1 5-5 9-3 5-9 4.0 3-3 1,9 50.1 50.49 Louisville i -7 2.1 2.8 5 -b 5-4 5-8 6.8 7-4 6.4 4.9 3-8 2.1 54.8 Indianapolis i -3 1.4 2.2 4.6 4.8 3-7 7-7 ■ 6.9 3-2 4.1 3 -i 1.6 48.6 41.36 Cincinnati 1.8 1.8 2.6 4.9 S* 2 6.4 6.3 6.6 6.1 4-7 3-3 2.1 52.0 34.88 Columbus 1.6 2.0 2-3 4-5 4.8 5-8 6.9 6.4 5 -i 4.0 2.6 1.8 47.8 35.06 Pittsburg r .4 1.9 2.2 3-8 4.2 5-4 6.6 5-6 4.9 3-4 2.8 2-3 44-5 39.89 Lower Lake Region. Buffalo 0.8 1. 1 1-3 2.2 3-3 3-9 4.9 5-2 3-9 2.8 1.9 1.6 32.9 33-87 Oswego 0.6 1.0 1. 1 2.2 2.8 3-8 3-9 4.0 3 -h 2.7 2.2 1.0 28.9 32-79 Rochester 0.5 1. 1 °-9 2.6 3-8 4.9 4.6 4.1 3-8 2.6 2.2 i -3 3 2 -4 27.76 Cleveland 1. 1 I.4 I - 5 2.9 3-3 4 4 5-2 4.9 3-8 3-4 2.4 1.4 35.7 32.57 Sandusky 0.8 1.4 i -5 3.2 3-7 4.6 5-4 5-4 3-7 3-4 2.2 i -3 36.6 26.45 Toledo °.o 1. 1 i -5 3-5 3-8 4.6 6.0 6.4 3-7 3-4 2.4 i -3 38.6 25.86 Detroit 0.0 1. 1 1.6 3 ° 4 1 4.8 5-9 5-2 3-4 2.8 2.0 i -3 36.0 29.02 Upper Lake Region. Grand Haven 0-5 O.7 i-3 2.6 3-i 3-8 4-7 3.8 2.7 2.6 i -7 I. I 28.6 25.96 Marquette 0.8 0.8 °-9 i -7 2.4 3-3 3-4 3-3 3- 1 2.2 i-3 *-3 24-5 35.40 Port Huron 0.6 1.0 I. I 2.6 3-o 38 4.6 4.2 3-2 2-5 i-7 1.0 29-3 24-33 Chicago 1.0 1.2 1.8 3-2 3-3 4.8 5-4 5-3 4.1 3.2 2-3 1.2 39-8 30.86 Milwaukee o -5 1.0 I. I 2.4 2.6 3.8 4.8 3-7 3-4 2.9 1.9 0.9 29.O 23-49 Duluth o -5 o-5 0.6 i -5 2.4 2-5 3-9 3-4 3° 2-5 1.2 1.0 23.0 27.31 Extreme Northwest. Moorhead 0.2 1.4 o -5 2.1 3-6 3.8 3-7 3-3 3-5 2.4 i -3 0.5 26.3 16.50 Saint Vincent o *3 o -3 o-5 1.8 3.8 3-9 3- 1 2.6 2.6 2.0 0.9 °-3 22.1 17.22 Bismark 0.4 0.6 0.6 3-o 4-3 4 - 1 5-6 4.2 4.0 2.6 1.2 0.4 31.0 16.51 Fort Buford 1.4 0.7 0.6 3-o 4-7 S.o 6.2 4.9 4.8 3-0 1-7 0.5 35-5 14.70 Fort Totton 0.2 o -3 0.4 2.2 4-6 3-8 4.2 3-7 3-7 2-3 1.4 0.4 27.2 16. 13 Upper Mississippi Valley. Saint Paul 0.7 0.7 2.2 2.0 2-3 4.1 5 -o 3-7 2.8 2.4 1-5 0.7 28.1 25.86 Davenport 0.5 1.0 1.8 3-8 3-4 4.6 6.Q 6.2 4.4 3 -o 2.3 1. 1 39 - 0 40.49 Des Moines 0.6 1.0 i-5 3-7 3-i 4.2 6.6 4-7 4.1 3-3 2.3 0.9 36.0 Keokuk 0.8 1. 1 2.1 4.2 3-7 4-3 7.0 6.8 3.0 3-8 2.9 1.2 42.9 35-79 S-8 4.4 4-3 5-6 6.5 4-5 3.8 Springfield, 111 0.8 1. 1 2.0 4.6 3-8 4-3 5-4 6-5 4-5 3-5 2.9 1.4 40.8 41.90 Saint Louis i -3 1.6 2-5 5-5 4-7 5 -o 7-5 8.0 5-9 4.9 3-9 i-4 52.2 41.17 Missouri Valley. Lamar I. I 1.6 2.4 4.4 3-8 4.0 6.0 4.6 3-7 3-6 2.9 i -5 39.6 42.91 Springfield, Mo I. I i-7 2-4 5-o 4.8 4.0 5 -o 3-4 3-4 3-5 3- 1 1.4 38- 3 42.12 Leavenworth 0.9 i -5 2.3 4.6 4-3 5 -o 6-3 4-5 4.0 3-9 2-7 1.4 41.6 47-21 Omaha 0.8 i-5 T -4 4-4, 3-8 5-2 6.2 5-2 4-3 4-3 3-0 1.4 41.7 24.22 Crete 0.7 1. 1 1.2 3-5 3-3 4-5 5-6 4-7 3-8 3-9 2.4 I.I 35-5 23-34 Fort Sulley 0.6 0.9 i-3 4.4 4.1 5-2 7-7 4-9 5-7 3.9 2.8 0.7 41.9 T 4- 77 Huron °-3 0.7 0.8 3-7 3-7 4- 1 3-7 4.2 4.1 3- 1 2.4 O.7 33 -o 17-05 Yankton 0.4 i-4 1.2 3-3 3 -i 4.4 4.6 3-7 2.9 3 ° 2.2 0.8 310 20.89 93c STORAGE AND EVAPORATION OF WATER. TABLE No. 27 a. — ( Continued .) Stations and Districts. 00 CO 00 c 1 — 1 00 00 00 V £ Mar. 1888. April, 1888. May, 1888. 00 00 c 00 00 j-f •—I Aug. 1887. Sept. 1887. Oct. 1887. Nov. 1887. Dec. 1887. 12 months’ Evaporation. Precipitation in 1888. 1 In. In. In. In. In. In. In. In. In. In. In. In. In. In. Northern Slope. Fort Assiniboine o.8 1.2 1.2 3.8 4* 1 4.2 6.8 5-5 4.8 3-5 2-5 1. 1 39-5 *3-99 Fort Custer o.6 i-5 i-3 5-4 6.8 4.9 9.6 8.0 6.1 3-4 2-9 i-5 52.0 13.98 Helena 1. 1 3-6 2.1 6. 1 4-3 5-5 7.2 7-7 6.4 4-3 3-0 2.1 53-4 10. 14 Cheyenne 3-3 5-7 4-0 8.2 5-2 10-4 8.0 7-7 8.6 5-8 6.1 3-5 76.5 J 4-5i North Platte o.8 1.8 1.8 5-4 3-9 6.9 6.0 4.8 3-7 2.8 2-3 1. 1 4«-3 17.46 Middle Slope. Denver 2.8 3-7 3-5 7.6 5.8 10.5 8.3 8.5 6.1 4-9 4.2 3-i 69.O 9-5 1 Dodge City 1.4 2-4 2.8 4.1 4.0 7-4 8.3 6.6 5-5 5-2 4.2 2.1 54-6 22.94 Fort Elliott 1-3 1.9 3.2 5-i 5-4 8.2 7.6 6.2 5-4 4-7 4.2 2.2 55-4 16.51 Southern Slope. Fort Sill i.6 2.0 2.6 3-8 4.0 4.4 4.8 7-5 5-i 4.2 4-1 2.0 46.I 35-72 Fort Davis 5-4 5-7 6.7 8-S II. O 12.0 II. 4 9.0 5-9 5-2 5 7 49 96.4 18. 11 Fort Stanton 3-9 3-9 5-a 7-3 9-5 10.9 9-4 11. 6 3-9 4.0 3-6 3-8 76.0 18.04 Southern Plateau. El Paso 4.0 3-9 6.0 8.4 10.7 13.6 9-4 7-7 3-6 5-2 4.6 2.9 82.0 Santa F6 3.0 3-4 4.2 6.8 8.8 12.9 9.2 9.8 6.6 6.7 5-7 2-7 79-8 12.03 Fort Grant 5-2 4.8 6.4 9.2 10.2 13.8 12.4 10.5 9.0 7-9 7.2 4.6 IOI.2 14.20 Yuma 4.4 5-2 6.6 9.6 9.6 12.6 II. O 10.2 8.2 8.2 5-5 4.6 95-7 2.95 Keeler 3.0 4.6 6-3 8.7 9-3 n.9 12.8 13.9 10.6 8.8 5-9 4.8 100.6 5.66 Middle Plateau. Fort Bid well 0.8 1.8 1.8 4.6 5-2 4.0 8.8 8.1 5-o 4.6 2.4 i-3 48.9 Winnemucca °-9 2.8 6.2 9.1 9-3 10. 1 “■5 12.0 9.9 6.6 3-7 1.8 83.9 4-89 Salt Lake City 1.8 2.7 3-6 7.2 6.9 8.9 9-2 10. 7 9.6 6-5 5-o 2-3 74-4 13.62 Fort Bridger 1.6 2-5 2.7 4-3 4-3 6.5 7-7 6.8 5-6 4.2 5-2 4-7 56.1 — Northern Plateau. Boise City 1.6 2-5 3.8 6.1 6-5 6.6 10. 0 9.2 7-4 5-2 3-2 1.8 63.9 11.09 Spokane Falls 0.7 i-7 2.7 4-4 5-4 4-4 7-7 6.4 3-8 2-5 1-7 1.4 42.8 17.69 Walla Walla- 1. 1 2.9 3-6 6.2 7-7 5-7 9.9 7-9 5-i 3-4 1.8 2.4 57-7 13-59 North Pacific Coast. Olympia i-3 1.2 1.8 2-5 4.1 3-3 3-2 3-i 2 4 i-5 i-3 1. 1 26.8 45-54 Port Angeles . . 1.0 0.9 1.8 1.8 2-5 2. 1 2.1 1.8 I -5 1.2 i-3 1. 1 19. 1 28.17 Astoria 1. 1 1.0 1.6 2.1 3-o 2-7 3-0 2.9 2.6 2.3 1.8 1.2 25-3 68.73 Portland 0.9 1. 1 2.4 3-4 5-o 3-2 5-4 4.2 3-4 2.7 1.8 1.2 34-7 38.76 Roseburg 1.2 1.6 2.7 3-9 4-7 3-5 5-4 4-7 5-o 3-2 x *7 1.6 39-2 31.19 Middle Pacific Coast. Red Bluff 3-0 4.6 5-4 6.1 7.0 6.9 11. 0 10.7 10. 1 10.5 5-9 3-6 84.8 24.94 Sacramento, 1.8 3-' 3-7 4-3 4.2 5-6 5-9 5.6 6.5 7-3 3-9 2.4 54-3 18.46 San Francisco 2.7 2.7 3-3 3-i 2.8 3-1 2.4 2-5 3-3 5.0 2.8 3-o 36-7 23- 03 Southern Pacific Coast. Fresno 1.8 2.8 3.0 5-6 6.0 7.0 9.1 10.2 7-6 6.7 3-8 2.2 65.8 8.76 Los Angeles 2-3 2.0 2.8 3-4 3-o 3-8 3-2 3-5 3-i 4.1 3° 3-0 37.2 21.04 San Diego 2.9 2.7 2-5 2.7 3-3 2.8 3-2 3-3 2.9 4-3 3-2 3-7 37-5 n-57 CHAPTER VI. SUPPLYING CAPACITY OF WATERSHEDS. 74. Estimate of Available Annual Flow of Streams. — Applying our calculations in the last chapter, of available flow of water from the unit of watershed, one square mile, and modifying it by the elements of compensation, storage, evaporation, and percolation, we then estimate mean annual quantities of low-cycle years, applicable to domestic con- sumption, as follows : Assumed mean annual rainfall 40 inches. Flow of stream available for storage, 40 per cent, of mean rain = 16 inches of rain. This available rain is applied to : ist. Compensation to riparian owners, say 16.8 p. c. of mean rain = 6.72 in. of rain. 2d. Evaporation from surface of storage reservoir, “ 3.2 “ “ “ “ =1.28 “ “ “ 3d. Percolation from storage reservoir, “ 1.6 “ “ “ “ = .64 “ “ “ 4th. Balance available for consumption, 18.4 “ “ “ “ = 7.36 “ “ “ Total 40 per cent. 16 inches. The 7.36 inches of rain estimated as available from a 40-inch annual rain equals 17,098,762 cubic feet of water, which is equivalent to a continuous supply of seven cubic feet per day (= 52.36 gals.) each, to 6,692 persons. By applying to the annual results the monthly ratios, and thus developing the monthly surpluses or deficiencies of flow, we shall have in the algebraic sum of the deficien- cies the volume of storage necessary to make forty per cent, of the rainfall available, and this storage must ordinarily approximate one-third of the annual flow T available for storage. s < Q Z o H O X U 94 (Constructed in 1836.) MONTHLY AVAILABLE STORAGE REQUIRED. 95 75. Estimate of Monthly Available Storage Re- quired. — Computation of a supply, and the required storage ; applied to one square mile of watershed as a unit of area. Assumed data : Population to be supplied. 6,500 per- sons, consuming 7 cubic feet per capita daily, each ; Mean annual rainfall, 40 inches, and eight-tenths = 32 inches of rain, in the low-cycle years ; Available flow of stream, fifty per cent, of eight-tenths of rain = 16 inches ; Compensation each month, .168 of one-twelfth the mean annual depth of rain = .56 niches each month uniformly ; Evaporation annually from the reservoir surface only, eighty per cent, of the depth of mean annual rain, or 32 inches; and monthly, eighty per cent, of one-twelfth the annual evaporation = 2 § inches. Area of storage reservoir, .04 square mile,* or 25.6 acres, with equivalent available draught of ten feet for that sur- face. The evaporation of two inches from four hundredths of a square mile = .10667 inch from one square mile. Volume of percolation assumed to equal f volume of evaporation from the reservoir surface. The monthly ratios will be multiplied into 40 in. x .8 x -50 p. c. _ j ,2333 in. for the monthly flow. 12 months .168 x 40 in. mean rain 12 months = .56 in. for monthly compensation. .04 x 4 _ ° m - x 80 p. c. _ -IC ,66y ; n f or monthly evap. from reservoir. 12 months “ =.0267 in. for monthly percolation from reservoir. 6500 x 7 cu. ft. x 30.4369 days = 1,384,879 cu. ft. for monthly con- sumption. * A unit of reservoir area, for each square mile unit of watershed. 96 SUPPLYING CAPACITY OF WATERSHEDS. TAB BE No. 28. Monthly Supply to, and Draft from, a Storage Reservoir. Month. Monthly Flow. cubic feet. Monthly Compen- sation. cubic feet. Monthly Evapora- tion from Reser- voir. cubic feet. Monthly Percola- tion from Reser- voir. cubic Jeet. Monthly Domestic Consump- tion. cubic feet. Surplus. cubic feet. Deficiency. cubic feet. Jan. | Gain. Ratio, 1.65 5,111,040 Loss. Ratio, .168 1,300,992 Loss. Ratio, .30 74»342 Loss. Ratio, .075 18,586 Used. Ratio, 1.05 1,454423 2,262,997 Feb. j Ratio, 1.50 4,646,400 .168 1 , 300,992 .318 78,803 .080 19,701 1. 10 1,523,367 1,723,537 Mar. | Ratio, 1.65 5,111,040 .l68 1 , 300,992 .426 105,566 .106 26,392 .90 1,246,391 2431,699 Apr. | Ratio, 1.45 4,491,520 .168 1 , 300,992 • 73 2 181,395 .183 45.349 .85 1,177447 1,786,637 May j Ratio, .85 2,632,960 .l68 1 , 300,992 1.128 279,528 .282 69,882 .90 1,246,391 264,033 June j Ratio, .75 2,323,200 .l68 1 , 300,992 i -53 379,146 •383 94,786 1. 00 1,384,879 836,603 July j Aug. j Ratio, .35 1,084,160 Ratio, .25 774,400 .l68 1 , 300,992 .168 1 , 300,992 183 453.489 '•95 483,721 ■457 113,372 .488 120,930 1.20 1,661,855 i. 25 1, 73 L 099 2,445,548 2,762,342 Sept. | Ratio, .30 929,280 .168 1,300,992 1-793 444,32° .448 1 1 1,080 1.05 M 54 ,I 23 2,382,235 Oct. -j Ratio, .45 1,393,920 .l68 1 , 300,992 1.005 261,438 .264 65,359 .90 1,246,391 1480,260 Nov. | Ratio, 1.20 3.717,120 .168 1 , 300.992 •558 138,277 .139 34,569 .85 M 77 ,I 47 1,066,114 Dec. | Ratio, 1.60 4,956,160 .168 1,300,992 .373 93.671 .095 23418 •95 1 , 315,635 2,222444 Totals 37,171,200 15,611,904 2,973,696 743,424 16,618,548 11493428 10,171,021 From certain localities no claim will arise for diversion of tlie water, or the diversion may be compensated for by the payment of a cash bonus, in which case the proportion of rainfall applicable to domestic consumption will be a little more than doubled, and approximately as follows, neglecting percolation from the storage reservoir. MONTHLY AVAILABLE STORAGE REQUIRED. 97 The monthly ratios will here be multiplied into 40 in. x .8 X .50 p. c. , ., a 5 — £ — = 1.3333 in. for the monthly now. 12 months 04 x — - X ‘8° P' — — .1067 in. for monthly evap. from reservoir. 12 months 13,500 persons x 7 cu. ft. x 30.4369 days = 2,876,287 cu. ft. foi monthly consumption. TABLE No. 29. Monthly Supply to, and Draft from, a Storage Reservoir (without compensation). Month. Monthly Flow. cubic feet. Monthly Evaporation | FROM Reservoir. cubic feet . Monthly Domestic Consumption. cubic feet. Surplus. cubic feet. Deficiency. cubic feet . Gain. Loss. Used . Jan. ] Ratio, 1.65 5,111,040 Ratio, .30 74.342 Ratio, 1.05 3,020,101 2,016,597 Feb. ] Ratio, 1.50 4,646,400 .318 78,803 1. 10 3> l6 3,9i6 1,403,681 Mar. | Ratio, 1.65 .426 105,566 .90 2,588,658 2,416,816 • Apr. | Ratio, 1.45 4,491,520 • 73 2 181,395 .85 2 , 444,844 1,865,281 May j Ratio, .85 2,632,960 1.128 279,528 .90 2,588,658 235,226 June j Ratio, .75 2,323.200 i- 53 ° 379.146 I. OO 2,876,287 932,233 July j Ratio, .35 1,084,160 I.83O 453.489 1.20 3,451,544 2,824,873 Aug. ] Ratio, .25 734,400 1.952 483,721 1-25 3^595,359 3,344,680 Sept. \ Ratio, .30 929,280 1-793 444, 3 2 ° 1.05 3,020,101 2,535>!4i Oct. | Ratio, .45 1,393,920 1.005 261,438 .90 2,588,656 1,556,174 Nov. | 1,133,999 Ratio, 1.20 3 , 7 I 7, I 20 .558 138,277 ■ 85 2 , 444,844 Dec. | Ratio, 1.60 4,956,160 .378 93,671 ■95 2,732,472 2,826,143 Tbtals, 37,171,200 2,973,696 34,515,442 11,662,517 11,428,327 7 98 SUPPLYING CAPACITY OF WATERSHEDS. 76. Additional Storage Required. — Forty inches of rainfall on one square mile equals a volume of 92,928,000 cubic feet. The deficiency as above computed is nearly twelve per cent, of this quantity, and calls for an available volume of water in store early in May, or at the beginning of a drought, equal to about one-eighth the mean annual rainfall. The calculations of supply and draught in the two monthly tables given above refer to mean quantities of low- cycle years, and not to extreme minimums. The seasons of minimum flow, which are also, usually, the seasons of maximum evaporation from the storage reservoirs and of maximum domestic consumption, are in the calculations supposed to be tided over by a surplus of storage provided in addition to the mean storage required for the series of low-cycle years. The storage should therefore be in excess of the mean deficiency as above computed at least twenty- five per cent., or should equal at least fifteen per cent, of the mean annual rainfall. If the storage is less than fifteen per cent., the safe available supply is liable to be less than the calculations given. If the area of the storage reservoir is greater per square mile of watershed than assumed above, the loss by evapo- ration from the water surface will be proportionately in- creased, and must be compensated for by increased storage. 77. Utilization of Flood Flows. — The calculations as above assume that fifty per cent, of the annual rainfall is the available annual flow in the stream. The remaining fifty per cent, is assumed to be lost through the various processes of nature and by floods. If the storage is still further increased, an additional portion of the flood flow can be utilized, and sometimes fifty per cent, or even sixty INFLUENCE OF STORAGE. 99 per cent, of the annual rainfall utilized for domestic con- sumption, or made applicable at the outlet of the reservoir for power. Hence, when it is desired to utilize the greatest possible portion of the flow, the storage should equal twenty or twenty-five per cent, of the mean annual rainfall. 78. Qualification of Deduced Ratios. — The ratios of flow, evaporation, and consumption, as above used iu the calculations, are not assumed to be universally appli- cable, but are taken as safe general average ratios for the Atlantic Coast and Middle States. The winter consump- tion will be less in the lower Middle and Southern States, and also in very efficiently managed w T orks of Northern States ; but the summer consumption tends to be greater in the lower Middle and Southern States, where the evapora- tion and rainfall are greater also. The results upon the Pacific slope can scarcely be gen- eralized to any profit, since within a few hundred miles it presents extremes, from rainless desert to the maximum rainfall of the continent, and from vaporless atmosphere to constant excessive humidity. 79. Influence of Storage upon a Continuous Supply. — A safe general estimate of the maximum contin- uous supply of water to be obtained from forty inches of annual rain upon one square mile of watershed, provided the storage equals at least fifteen per cent, of the rainfall, gives 7 cubic feet (=52.36 gals.) per capita daily, to from 13000 to 15000 persons, dependent upon the amount of available storage of winter and flood flows ; or say, three- quarters of a million gallons of water daily. The same area and rain, with but one month’ s deficiency storage, can be safely counted upon to supply but about 3,000 persons with an equal daily consumption, or 157,000 gallons of water daily. From the same area and rain, with 100 SUPPLYING CAPACITY OF WATERSHEDS. no storage , a flashy stream may fail to supply 1.000 persons to the full average demand in seasons of severe drought. Hence the importance of the storage factor in the calcu- lation. The above estimates are based upon mean rainfalls of low-cycle (§ 47) years ; therefore the results may be ex- pected to be twenty per cent, greater in years of general average rainfall. 80. Artificial Gathering Areas. — When resort is necessarily had to impervious artificial collecting areas for a domestic water supply, as when dwellings are located upon vegetable moulds or low marsh areas, bituminous rock surfaces, limestone surfaces, or, as in Venice, where the sheltering roofs are the gathering areas of the house- holds, the proportion of the rainfall that may be run into cisterns is very large. If such cisterns are of sufficient capacity and their waters protected from evaporation, eighty per cent, of the rainfall upon the gathering areas may thus be made available, though special provisions for its clarifi- cation will be indispensable. In such case, a roof area equivalent to 25 feet by 100 feet might furnish from a forty-inch rainfall a continuous supply of 3 cubic feet (— 22.44 gallons) per day to six per- sons, which would be abundant for the household uses for that number of persons. 81. Recapitulation of Rainfall Ratios. — Recapitu- lating, in the form of general average annual ratios, relating to the mean rainfall upon undulating crystalline or diluvial surface strata, as unity, we have : Ratio of mean annual rainfall i.oo Ratio of mean rainfall of lowest three-year cycles So Ratio of minimum annual rainfall 70 Ratio of mean annual flow in stream (of the given year’s rain) 60 RAINFALL RATIOS. 101 Ratio of mean summer flow in stream (of the given year’s rain) 25 Ratio of low summer flow in stream “ “ “ 05 Ratio of annual available flow in stream “ “ 50 Ratio of storage necessary to make available 50 per cent, of annual rain. .15 Ratio of general evaporation from earths, and consumption by the pro- cesses of vegetation 40 Ratio of percolation through the earth (included also in the flow of streams) 25 Ratio of mean rainfall collectible upon impervious artificial or primary rock surfaces 80 The monthly ratios of these annual ratios are to be taken in- ordinary calculations of water supplies, and each annual ratio to be subjected to the proper modification adapting it to a special local application. TABLE No- 30. Ratios of Monthly Rain, Flow, Evaporation, and Consumption. c 03 Feb. n s a < cT June. _>> 3 1 — 1 fci) 3 < 0. c n 0 Nov. Dec. Ratios of average monthly rain •75 ■83 ,qo 1 . 10 1.30 I .08 I . 12 1 . 20 1 .00 -95 -93 .84 Ratios of av. monthly flow of streams i.b 5 1.50 1.65 i -45 •85 -75 • 35 •25 •30 •45 1 . 20 1.60 Ratios of av. monthly evap from water Ratios of average monthly consumption • 3 ° .32 •43 •73 1 • 53 1 83 1.95 1 • 79 1.05 •56 .38 of water 1.05 I . IO .90 •85 .90 I .OO 1 . 20 1.25 1 05 .90 •85 ■95 TABLE No. 30a. Example of an Estimate of Collectable Rainfall.* j Assumed annual rainfall 40 in. 1 "j Average available monthly flow f 1.667 c a Feb. j March. April. cS June. fci < Sept. O O Nov. Dec. Total. Ratio of monthly mean available flow 1.65 1.50 1.65 1-45 .85 •75 ■35 •25 •30 •45 1.20 t . 60 12.00 Equivalent inches ol monthly avail- able flow 2-75 2.50 2.75 2.42 I.42 125 .58 • 4 i •50 75 2.00 2.67 20.00 Eight-tenths of do Inches of rain monthly to satisfy 2.20 2.00 2.20 1 i -93 1. 13 1 .00 •47 ■33 .40 .60 I.60 2. 13 16.00 riparian rights •56 ■561 -56 ■56 .56 .56 •47 •33 .40 •56 •56 •56 6.25 Inches ot rain collectable monthlv, for storage 1 .64 I.44 I.64 i -37 ■ 57 •44 .00 .00 .OO .04 I.04 i -57 9-75 The inches of rainfall flowing monthly, here assigned as a riparian right, are found by taking the mean of flows from June to October inclusive, thus: 1. 00 -f- .47 -f- .33 -}- .40 -f- .60 inches . , c — -t'— ! — f — = .56 inches of rain. 5 months This allows to riparian rights the entire low water flow of summer, and allows for losses of rainfall approximately as follows: Loss by evaporation and absorption, 12 in.; loss by floods, 8 in.; reduced flow in dry seasons, 4 in.; remaining available flow, 16 in. * Relating to the Adirondack water shed of Hudson River. From “ Report on a Water Supply for New York and other Cities of the Hudson Valley, by J. T. Fanning. N. Y. 1881. CHAPTER VII. SPRINGS AND WELLS. 82. Subterranean Waters. — A portion of tlie rain, perhaps one-fourth part of the whole, distilled upon the surface of the earth, penetrates its soils, the interstices of the porous strata, the crevices of the rocks, and is gathered in the hidden recesses. These subterranean reservoirs were filled in the unexplored past, and their flow continues in the present as they are replenished by new rainfalls. 83. Tlieir Source the Atmosphere. — AVe find no reason to suppose that Nature duplicates her laboratory of the atmosphere in the hidden recesses of the earth, from whence to decant the sparkling springs that issue along the valleys. On the other hand, we are often able to trace the course of the waters from the storm-clouds, into and through the earth until they issue again as plashing fountains and flow down to the ocean. The clouds are the immediate and only source of supply to the subterranean watercourses, as they are to the sur- face streams we have just passed in review. The subterranean supplies are subject indirectly to at- mospheric phenomena, temperatures of the seasons, surface evaporations, varying rainfalls, physical features of the surface, and porosity of the soils. Especially are the shal- low wells and springs sensitively subject to these influences. 84. Porosity of Earths and Rocks. — Respecting the porosity and absorptive qualities of different earths, it may be observed that clean silicious sand, when thrown loosely together, has voids between its particles equal to nearly Fir. 131 INTERCEPTING WELL, PROSPECT PARK, BROOKLYN. THEIR SOURCE THE ATMOSPHERE. 103 one-third its volume of cubical measure ; that is, if a tank of one cubic yard capacity is filled with quartzoid sand, then from tliirty-to thirty-five per cent, of a cubic yard of water can be poured into the tank with the sand without overflowing. Gravel, consisting of small water- worn stones or pebbles, intermixed with grains of sand, has ordinarily twenty to twenty-five per cent, of voids. Marl, consisting of limestone grains, clays, and silicious sands, has from ten to twenty per cent, of voids, according to the proportions and thoroughness of admixture of its Eonstituents. Pure clays have innumerable interstices, not easily measured, but capable of absorbing, after thorough drying, from eight to fifteen per cent, of an equal volume of water. The water contained in clays is so fully subject to laws of molecular attraction, owing to the minuteness of the individual interstices, that great pressure is required to give it appreciable flow. Water flows with some degree of freedom through sand- stones, limestones, and chalks, according to their textures, and they are capable of absorbing from ten to twenty per cent, of their equal volumes of water. The primary and secondary formations, according to geological classification, as for instance, granites, serpen- tines, trappeans, gneisses, mica-slates, and argillaceous schists, are classed as impervious rocks, as are, usually, the several strata of pure clays that have been subjected to great superincumbent weight. The crevices in the impervious rocks, resulting from rupture, may, however, gather and lead away, as natural drams, large volumes of the water of percolation. The free flow of the percolating water toward wells or 104 SPRINGS AND WELLS. spring, is limited and controlled, not only by the porosity of the strata which it enters, bat also by their inclination, curvature, and continuous extent, and by the impervious- ness of the underlying stratum, or plutonic rock. 85. Percolations in the Upper Strata. — Shallow well and spring supplies are, usually, yields of water from the drift formation alone. Them temperatures may be va- riable, rising and falling gradually with the mean tempera- tures of the surface soils in the circuits of the seasons, and they may not be wholly freed from the influence of the decomposed organic surface soils. Their flow is abundant when evaporation upon the surface is light, though slack- ened when the surface is sealed by frost. A variable spring, and it is the stream at its issue that we term a spring, indicates, usually, a flow from a shallow, porous surface stratum, say, not exceeding 50 feet in depth, though occasionally its variableness is due to peculiar causes, as the melting of glaciers in elevated regions, and atmospheric pressure upon sources of intermittent springs. Porous strata of one hundred feet in depth or more give comparatively uniform flow and temperature to springs. 86. The Courses of Percolation — Gravitation tends to draw the particles of water that enter the earth directly toward the center of the earth, and they percolate in that direction until they meet an impervious strata, as clay, when they are forced to change their direction and follow along the impervious surface toward an outlet in a valley, and possibly to find an exit beneath a lake or the ocean. When the underlying impervious strata has considerable average depth, it may have been unevenly deposited in consequence of eddies in the depositing stream, or crowded into ridges by floating icebergs, or it may have been wojt into valleys by flowing water. Subsequent deposits of SUBTERRANEAN RESERVOIRS. 105 sand and gravel would tend to fill up the concavities and to even the new surface, hiding the irregularities of the lower strata surface. The irregularities of the impervious surface would not be concealed from the percolating waters, and their flow would obey the rigid laws of gravitation as unswervingly as do the showers upon the surface, that gather in the chan- nels of the rocky hills. Springs will appear where such subterranean channels intercept the surface valleys. The magnitude of a spring will be a measure of the magnitude of its subterranean gathering valley. 87. Deep Percolations. — The deep flow supplies of wells and springs are derived, usually, from the older porous stratifications lying below the drift and recent clays. The stratified rocks yielding such supplies have in most instances been disturbed since their original depositions, and they are found inclined, bent, or contorted, and some- times rent asunder with many fissures, and often intercepted by dykes. 88. Subterranean Reservoirs. — Subterranean basins store up the waters of the great rain percolations and deliver them to the springs or wells in constant flow, as surface lakes gather the floods and feed the streams with even, continuous delivery. A concave dip of a porous stratum lying between two impervious strata presents favor- able conditions for an “artesian” well, especially if the porous stratum reaches the surface in a broad, concentric plane of great circumference, around the dip, forming an extensive gathering area. Waters are sometimes gathered through inclined strata from very distant watersheds, and sometimes their course 106 SPRINGS AND WELLS. leads under considerable bills of more recent deposit than the stratum in which the water is flowing. The chalks and limestones do not admit of free percola- tion, and are unreliable as conveyers of water from distant gathering surfaces, since their numerous fissures, through which the water takes its course, are neither continuous nor uniform in direction. 89. The Uncertainties of Subterranean Searches. — The conditions of the abundant saturation and scanty saturation of the strata, and their abilities to supply water continuously, are very varied, and may change from the first to the second, and even alternate, with no surface indi- cations of such result ; and the subterranean flow may, in many localities, be in directions entirely at variance with the surface slopes and flow. Predictions of an ample supply of water from a given subterranean source are always extremely hazardous, until a thorough knowledge is obtained of the geological posi- tions, thickness, porosity, dip, and soundness of the strata, over all the extent that can have influence upon the flow at the proposed shaft. Experience demonstrates that water may be obtained in liberal quantity at one point in a stratum, while a few rods distant no water is obtainable in the same stratum, an intervening “fault” or crevice having intercepted the flow and led it in another direction. Sometimes, by the exten- sion of a heading from a shaft in a water-bearing stratum, to increase an existing supply, a fault is pierced and the existing supply led off into a new channel. 90. Renowned Application of Geological Science. — Arago’s prediction of a store of potable water in the deep- dipping greensand stratum beneath the city of Paris, was one of the most brilliant applications of geological science INFLUENCE OF WELLS UPON EACH OTHER. 107 to useful purposes. He felt keenly that a multitude of his fellow-citizens were suffering a general physical deteriora- tion for want of wholesome water, for which the splendors of the magnificent capital were no antidote. With a fore- sight and energy, such as displays that kind of genius that Cicero believed to be “in some degree inspired,” he pre- vailed upon tlie public Minister to inaugurate, in the year 1833, that notable deep subterranean exploration at Cre- nelle. By his eloquent persuasions he maintained and defended the enterprise, notwithstanding the eight years of labor to successful issue were beset with discouragements, and all manner of sarcasms were showered upon the pro- moters. In February, 1841, the augur, cutting an eight- inch bore, reached a depth of 1806 feet 9 inches, when it suddenly fell eighteen inches,, and a whizzing sound an- nounced that a stream of water was rising, and the well soon overflowed. 91. Conditions of Overflowing- Wells. - An over- flow results only when the surface that supplies the water- bearing stratum is at an elevation superior to the surface of the ground where the well is located, and the water-bearing stratum is confined between impervious strata. In such case, the hydrostatic pressure from the higher source forces the water up to the mouth of the bore. 93. Influence of Wells upon Each Other. — The success of wells, penetrating deep into large subterranean basins, upon their first completion, has usually led to their duplication at other points within the same basin, and the flow of the first has often been materially checked upon the commencement of flow in the second, and both again upon the commencement of flow in a third, though neither was within one mile of either of tlie others. The flow cf the famous well at Greuelle was seriously checked by the open- 108 SPRINGS AND WELLS. ing of another well at more than 3000 yards, or nearly two miles distant. 93. American Artesian Wells. — The snb-stratnm which, in the United States has been most successfully pierced for artesian waters is the coarse Potsdam sand- stone having its northerly outcrop in central Wisconsin. This stratum is now well known as far easterly as Chi- cago and Milwaukee, as far westerly as the Mississippi river, and southerly into central Illinois. The wells in this sandstone for public water supplies are numerous and the water generally satisfactory for domestic uses, but having considerable mineral impregnations. The granite outcrop in Wisconsin extends from the ridge near the southern shore of Lake Superior, southerly to the centre of the state and there dips. Southerly of the dip the water- bearing Potsdam sandstone lies upon the granite and has width of outcrop of about sixty miles on a north and south line midway between lake and river, and then glasses under a magnesian limestone. Upon this limestone is a layer of St. Peter sandstone, also water-bearing, and this last is covered by yellow Galena and blue Trenton limestones and in Illinois by shales, with occasional lower coal measures. The wells of this locality have depths varying from 1200 to 2000 feet usually, according to the relative altitudes of the ground surface and water-bearing stratum. These wells are usually lined through the upper strata with six or eight inch iron pipes, and cost from three to five dollars per foot of depth. These wells usually overflow, with a moderate pressure when first drilled, and give mean deliveries of from 90.000 to 350,000 gallons of water per twenty-four hours, but with gradual decrease of flow at each well as additional wells are opened. ARTESIAN WELL STRATA. GEOLOGICAL SECTION IN NORTHERN ILLINOIS AND SOUTHERN WISCONSIN. SPRINGS AND WELLS. 108 a The piesometric slope of water pressure along this north and south line, prolonged, is about one foot per mile, indicat- ing a much fissured as well as coarse grained porous rock. The well waters have temperatures of about 60 ° Fall. The next best known artesian basin is beneath the James River valley in the Dakotas, where many borings have been made for water supply and irrigation purposes. Some of the wells opened in South Dakota have pressures equivalent to one hundred feet head and upwards, and their waters have been utilized for mechanical power. The deep wells east of the Alleghany mountains and especially in eastern New England, have not generally been successes in either quantity or quality of water. Piped Drift Wells, usually termed driven wells, have become much used in the sources of water supply for small towns. The best condition for these is usually an inclined thick stratum of course siliceous sand resting upon imper- vious clay or rock and covered with a stratum of imper- vious clay. This water-bearing sand stratum is the counter- part of the water-bearing sandrock stratum in the successful deep artesian wells, and for continued success it must have a very large relative outcrop for a watershed. Sometimes a location is found, where a former basin or bay in the land has subsequently been filled by a deposit of gravel or sand, and this deposit gathers a considerable portion of the rain that falls upon its surface and upon the adjoining higher grounds. In such case the site, if there are not sanitary objections, is favorable for driven pipe wells. Sometimes extensive deposits of sand or gravel beside a lake or water course, or such deposits made by ancient floods, present facilities for successful driven wells. The cities of Brooklyn, L. I., and Memphis, Tenn., have very unusual facilities of this kind. 1086 SPRINGS AND WELLS. The pipes of these wells have now usually ingenious strainers at their feet, intended to admit waters freely hut to exclude the sand. When a considerable quantity of water is desired a group or line of pipe is sunk at right angles to the line of subterranean flow, and if pumping is necessary the tops of the pipes are coupled in to one main which is connected with the suction chamber of the pump. The success of these drift pipe wells in both quantity and quality of water has many uncertainties until actual test shows results, unless the geological conditions are fully known, but fortunately the conditions of the drift sub-strata may often be more easily studied than can those of the rock sub-strata for deep artesian wells. General practice seems to sanction an ordinary rate of flow in the well pipes about as follows, although great natural pressures and pump suctions may at times increase these rates, when the rock is so fissured, or the rock or sand is so coarse, as to permit an increased quantity of water to enter the bore in the rock, or the pipe strainer. TABLE No. 3 1 a. Ordinary Rate of Flow in Well Pipes. Diameter of Pipe. Cubic feet per minute. Gallons per 24 hours. Number of Pipes for 1 million Gallons per 24 Hours. Inches. 2^ 2.0 21,542 46 3 , 3-° 32.30 3 1 3-8 40»93i 25 4 5-o 53.856 66,781 19 4 ^ 6.2 15 5 7-8 84,015 12 6 II. 2 120,637 9 7 15.0 161,568 6 8 : 9-5 210,038 5 IO 30.0 3 z 3. i 36 3 94. Watersheds of Wells.— The watershed of a deep subterranean supply is not so readily distinguishable as is WATERSHEDS OF WELLS. 109 tliat of a surface stream, that usually has its limit upon the crowu of the ridge sweeping around its upper area. The subterranean watershed may possibly lie in part beyond the crowning ridge, where its form is usually that of a concentric belt, of varying width and of yarying sur- face inclination. A careful examination of the position, nature, and dip of the strata only, can lead to an accurate trace of its outlines. The granular structure of the water-bearing stratum, as a vehicle for the transmission of the percolating water, is to be most carefully studied ; the existence of faults that may divert the flow of percolation are to be diligently sought for ; and the point of lowest dip in a concave subterranean basin or the lowest channel line of a valley-like subterra- nean formation, is to be determined with care. A depressed subterranean water basin, when first dis- covered, is invariably full to its lip or point of overflow. Its extent may be comparatively large, and its watershed comparatively small, yet it will be full, and many centuries may have elapsed since it was moulded and first began to store the precious showers of heaven. A few drops accu- mulated from each of the thousand showers of each decade, may have filled it to its brim many generations since ; yet this is no evidence that it is inexhaustible. If the perennial draught exceeds the amount the storms give to its replen- ishment, it will surely cease, in time, to yield the surplus. Coarse sands will, when fully exposed, absorb the greater portion of the showers, but such sands are usually covered with more or less vegetable soil, except in regions where showers seldom fall. Fissured limestones and chalks will also absorb a large portion of the storms, if exposed, but they are rarely en- tirely uncovered except upon steep cliff faces, where there 110 SPRINGS AND WELLS. is little opportunity for the storms that drive against them to secure lodgement. 95. Evaporation from Soils.— Vegetable and surface soils that do not permit free percolation of their waters downward to a depth of at least three feet, lose a part of it by evaporation. On the other hand, evaporation opens the surface pores of close soils, so that they receive a por- tion of the rain freely. 96. Supplying- Capacity of Wells and Springs.— Percolation in ordinary soils takes place in greatest part in the early spring and late autumn months, and to a lim- ited extent in the hot months. In cold climates it ceases almost entirely when the earth is encased with frost. Permanent subterranean well or spring supplies receive rarely more than a very small share of their yearly replen- ishment between each May and October, then- continuous flow being dependent upon adequate subterranean storage. Such storage may be due to collections in broad basins, to collections in numerous fissures in the rocks, or to very gradual flow long distances through a porous stratum where it is subject to all the limiting effects of retardation included under the general term, friction. In the latter case a great volume of earth is saturated, and a great volume of water is in course of transmission, and the flow continues but slightly diminished until after a drought upon the surface is over and the parched surface soils are again saturated and tilling the interstices of perco- lation anew. For an approximate computation of the volume of per- colation into one square mile of porous gathering area, covered with the ordinary superficial layer of vegetable soil, and under usual favorable conditions generally, let us assume that the mean annual rainfall is 40 inches in depth, SUPPLYING CAPACITY OF WELLS AND SPRINGS. Ill and that in the seasons of droughts, or the so-called dry years, 60 per cent, of the mean monthly percolation will take place. TABLE No. 3 1. Percolation of Rain into One Square Mile of Porous Soil. Assumed Mean Annual Rain 40 Inches Depth. c rt •— > Feb. u rt Apr. ci 2 When alcohol is poured into water it does not become a part of the water, but is diffused through it. This we are assured of, since by an ingenious operation we are able to syphon the alcohol out of the water by a method entirely mechanical. If we put some sugar, or alum, or carbonate of soda into water, the water will cause the crystals to separate and be diffused throughout the liquid, but they will not be a part of the water. The water HORIZONTAL TURBINES AND PUMPS. To face P . 112. Wilxim antic Water Works. Conn. PROPERTIES OF WATER. 113 might be evaporated away, when the sugar, or alum, or soda would have returned to its crystalline state. In these cases, the surplus hydrogen, the alcohol, and the constitu- ents of the crystalline ingredient are diffused through the water as impurities. If in a running brook a lump of rock salt is placed, the current will flow around it, and the water attack it, and will dissolve some of its particles, and they will be diffused through the whole stream below. A like effect results when a streamlet fl ows across a vein of salt in the earth. In like manner, if water meets in its passage over or through the earth, magnesium, potassium, aluminium, iron, arsenic, or other of the metallic elements, it dissolves a part of them, and they are diffused through it as impurities. In like manner, if water in its passage through the air, as in showers, meets nitrogen, carbonic acid, or other gases, they are absorbed and are diffused through it as impurities. 99. Properties of Water. — Both oxygen gas and hydrogen gas, when pure, are colorless, and have neither taste nor smell. Water, a result of their combination, when pure, is transparent, tasteless, inodorous, and colorless, except when seen in considerable depth. The solvent powers of water exceed those of any other liquid known to chemists, and it has an extensive range of affinities. This is why it is almost impossible to secure water free from impurities, and why almost every substance in nature enters into solution in water. There is a property in water capable of overcoming the cohesive force of the particles of matter in a great variety of solids and liquids, and of overcoming the repulsive force in gases. The par- ticles are then distributed by molecular activities, and the result is termed solution. Some substances resist this action of water with a large 114 IMPURITIES OF WATER. degree of success, tliougli not perfectly, as rock crystals, various spars and gems, and vitrified mineral substances. 100. Physiological Effects of the Impurities of Water. — When we remember that seventy-five per cent, of our whole body is constituted of the elements of water, that not less than ninety-five per cent, of our healthy blood, and not less than eighty per cent, of our food is also of water, we readily acknowledge the important part it plays in our very existence. Water is directly and indirectly the agency that dissolves our foods and separates them, and the vehicle by which the appropriate parts are transmitted in the body, one part to the skin, one to the finger-nail, one to the eye-lash, to the bones phosphate of lime, to the flesh casein, to the blood albumen, to the muscles fibrin, etc. When the stomach is in healthy condition, nature calls for water in just the required amount through the sensation, thirst. Good water then regulates the digestive fluids, and repairs the losses from the watery part of the blood by evaporation and the actions of the secreting and exhaling organs. Through the agency of perspiration it assists in the regula- tion of heat in the body ; it cools a feverish blood ; and it allays a parching thirst more effectually than can any fer- mented liquor. Water is not less esseutial for the regula- tion of all the organs of motion, of sight, of hearing, and of reason, than is the invigorating atmosphere that ever sur- rounds us, to the maintenance of the beating of the heart. If from a simple plant that may be torn asunder and yet revive, or a hydra that may be cut across the stomach or turned wrong side out and still retain its animal functions, the water is quite dried away, if but for an instant, man, with his wonderful constructive ability, and reason almost MINERAL IMPURITIES. 115 divine, cannot restore that water so as to return the activity of life and the power of reproduction. The human stomach and constitution become toughened in time so as to resist obstinately the pernicious effects of certain of the milder noxious impurities in water, but such impurities have effect inevitably, though sometimes so grad- ually that their real influence is not recognized until the whole constitution has suffered, or perhaps until vigor is almost destroyed. Note the effect of a few catnip leaves thrown into drink- ing water, which will act through the water upon the nerves ; or an excess of magnesia in the water will neutralize the free acids in the stomach, or lead in the water will act upon the gums and certain joints in the limbs, or alcohol will act upon the brain ; and so various vegetable and mineral solu- tions act upon various parts of the body. It would be fortunate if the pernicious impurities in water affected only matured constitutions, but they act with most deplorable effect in the helplessness of youth and even before the youth has reached the light. These impurities silently but steadily derange the digestive organs, destroy the healthy tone of the system, and bring the living tissues into a condition peculiarly predisposed to attack by malig- nant disease. 101. Mineral Impurities. — The purest natural waters found upon the earth are usually those that have come down in natural streams from granite hills ; but if a thou- sand of such streams are carefully analyzed, not one of them will be found to be wholly free from some admixture. This indicates that in the economy of nature it has not been ordained to be best for man to receive water in the state chemically called pure. A United States gallon of water weighs sixty thousand grains nearly. Such waters as phy- 116 IMPURITIES OF WATER. sicians usually pronounce good potable waters have from one to eight of these grains weight, in each gallon, of certain impurities diffused through them. 'These impurities are usually marshalled into two general classes, the one derived more immediately from minerals, the other derived directly or indirectly from living organisms. The first are termed mineral impurities, and the other organic impurities. The mineral impurities may be resolved by the chemist into their original elementary forms, and they are usually found to be one or more of the most generally distributed metallic elements, as calcium, magnesium, iron, sodium, potassium, etc. If as extracted they are found united with carbonic acid, they are in this condition termed carbonates ; if with sulphuric acid, sulphates ; if with silicic acid, sili- cates ; if with nitric acid, nitrates ; if with phosphoric acid, phosphates , etc. ; if one of these elements is formed into a compound with chlorine, it is termed a chloride; if with bromine, it is termed a bromide , etc. A few metallic ele- ments may thus be reported, in different analyses, under a great variety of conditions. 102. Organic Impurities. — There are a few elements that united form organic matter, as carbon, oxygen, hydro- gen, nitrogen, sulphur, phosphorus, potassium, calcium, sodium, silicon, manganese, magnesium, chlorine, iron, and fluorine. Certain of these enter into each organized body, and their mode of union therein yet remains sealed in mys- tery. In the results we recognize all animated creations, from the lowest order of plants to the most perfect quadru- peds and the human species. All organic bodies may, however, upon the extinction of their vitality, be decom- posed by heat in the presence of oxygen, and by fermenta- tion and putrefaction. The metallic elements are, in the impurities of good ANALYSES OF POTABLE WATERS. 117 potable waters, usually much in excess of the organic ele- ments, but the contained nitrogenized organic impurities indicate contaminations likely to be much more harmful to the constitution, and especially if they are products of ani- mal decompositions. 103. Tables of Analyses of Potable Waters.— We will quote here several analyses of running and quiet waters that have been used, or were proposed for public water supplies, indicating such impurities as are most ordinarily detected by chemists in water. For condensation and for convenience of comparison they are arranged in tabular form. TABLE No. 3 2. Analysis of various Lake, Spring, and Well Waters. Jamaica Pond, near Brooklyn, L. 1 . Flax Pond, near Lynn, Mass. Sluice Pond, near Lynn, Mass. Breeds Pond, near Lynn, Mass. Reeds’ Lake, near Grand Rapids, Mich. Lake Konomac, near New London, Conn. Loch Katrine, near Glasgow, Scotland. Soring Water, near Clapham, England. Well at Highgate, England. Artesian Well, at Hatton, ( England. Artesian Well, at Colney Hatch, England. Carbonate of Lime 1.092 .700 .400 .600 4.65 .O96 12.583 1.768 5-420 “ Magnesia . .408 .692 .32° .6l2 1.13 .216 n.658 •734 I.IOI “ Soda 12.677 5-921 Protocarbonate ot Iron. . 4.00 Chloride of Sodium .244 .612 .408 .504 2.l8 9-556 8.032 7-745 “ Magnesia . . . .328 trace 3-553 “ Calcium. . . . .120 .... .144 4.930 “ Potassium... 1.62 Alkaline Chlorides •433 Sulphate of Lime .120 .300 • 3 °° .270 1.29 .381 12.775 3.798 “ Magnesia... .288 .050 “ Potash .064 .070 14.217 trace 2.160 “ Potassa .080 .086 '.880 5.662 8.776 7-935 8.719 trace Phosphate of Lime trace trace Nitrate of Lime 33-457 “ Magnesia 14.231 Oxide of Iron .044 .840 trace .O96 .85 .035 trace Ammonia Silica .156 .144 .120 •75 2-43 .170 .200 •747 .042 •559 Organic Matter .008 2.208 1-344 2.184 8.75 1.80 .900 3-419 Total Solids to 1 b\ | 5-652 3.072 5 - 3 l6 I 7-750 7-831 2.244 64.629 83-549 35-685 27-323 Soluble Organic Matter. Hardness, Degrees by .... .392 Clark’s Scale I 1 0.80 .... 118 IMPURITIES OF WATER. TABLE Analysis of various The quantities are expressed in grains per U. S. Gallon ot 231 cubic inches, or 58,3721^0 grains. Hudson River, above Albany, N. Y. 1 Hudson River, above Poughkeepsie, N. Y. Connecticut River, above Holyoke, Mass. Connecticut River, above Springfield, Mass. 0 0 • i33 1.680 •3° .46 I. 104 2.880 .776 I.728 .67 2.685 12.699 4.408 6.007 4.24 7.719 6.624 Soluble Organic Matter Solid residue obtained on evaporation. Hardness, Degree by Clarke’s Scale. .. 3-35 •43 •51 :::: :::: * Notwithstanding the exceeding importance of an intelligent microscopi- cal examination of each proposed domestic water supply, in addition to the chemical analysis, no record of such examination is found accompanying the reports upon the waters herein enumerated. Lenses of the highest microscop- ical powers should he used for such purpose, and immersion lenses are required in many instances. To obtain specimens of sedimentary matters, the sample of water may first ANALYSIS OF POTABLE WATERS. 119 No. 33. River and Brook Waters.* Chickopee River, near Springfield, Mass. Mill River, near Springfield, Mass. Grand River, above Grand Rapids, Mich. White River, in Filter Wells on Bank, at Indianapolis, Md. Fallkill Creek, near Poughkeepsie, N. Y. Wapinger’s Creek, near Poughkeepsie, N. Y. Lynde Brook, near Worcester, Mass. Thames River, above London, Eng. Dee River, near Aberdeen, Scotland. New River, London, Eng. Hampstead Water Co.’s Supply, England. Cowley Brook, near Preston, Eng. Loud Scales, Preston, England. Dutton Brook, near Preston, Eng. •65 1.30 7.l8 10.02 .51 6.221 •334 13.13 .709 6.521 4.128 •575 6.131 1-343 •59 .87 I.84 •05 .909 2.944 ■238 .966 .217 .40 .322 4-245 .147 .242 .152 •53 2 .865 4.7O 1.20 trace 1.56 1.442 5.662 -938 •55o .970 .091 2-37 •334 •3 X 7 •75 .07 I.38 1.501 .64 .11 •559 •13 .260 3.00 2.73 .101 2.693 •175 .321 .105 •394 .926 1.167 .287 •133 ■ 159 trace .092 .150 1.242 12.625 .780 .171 .093 •348 .017 .058 trace trace .72 1.66 .851 .167 •13 trace trace trace trace .12 trace i-37 trace .05 .275 .27 .417 .058 •425 •334 .401 1. 104 3.864 18.75 •50 •15 trace .417 2.37 2.327 i-535 4.516 7-339 3 x - 2 4 2O.99 6.74 11.459 1.727 20.19 16.496 29.678 3 - 3 x 7 1-774 3 - 9 12 I.167 I. l68 .785 16.327 25.527 3-5°2 9.340 4- x 44 6.037 5-562 4-633 • 3 ° •63 14.5 14.9 9.8 x.25 12 1.50 rest a day in a deep, narrow dish, and then have its clear upper water syphoned off. The remainder of the water may then be poured into a conical glass, such as, or similar to, the graduated glasses used by apothecaries, and then again allowed to rest until the sediment is concentrated, when the greater part of the clear water may he carefully syphoned off and the sediment gathered and transferred to a slide, where it should be protected by a thin glass cover. 120 IMPURITIES OF WATER TABLE No. 34. Analysis of Streams in Massachusetts.* (Quantities in Grains per U. S. Gallon.) Solid Residue of Filtered Water. Free Ammonia. Albuminoid Ammonia. Inorganic. Organic and Volatile. Total. Chlorine, Merrimac River — Mean of n ex- aminations above Lowell O.OO27 0.0066 1.38 1 .01 2.39 | 0.08 Merrimac River— Mean of 12 ex- aminations above Lawrence .0026 .0064 1. 41 .98 2 -39 .12 Merrimac River — Mean of 11 ex- aminations below Lawrence .0018 .0074 I.54 1.05 2-59 .11 Blackstone River, near Quinsig- amund Iron Works .105 .015 I.98 1.98 3 * 9 ^ .50 Blackstone River, just above Mill- bury .024 .012 2.62 1 • 75 4-37 .» Blackstone River, below Black- stone .004 .008 1.66 1 .21 2.87 .21 Charles River, at Waltham .0035 .0096 2.26 1.07 3-33 .23 Sudbury River, above Ashland. . . . .0030 .0107 1.63 2.50 4-13 .23 Sudbury River, at Concord .0026 .0115 2.22 1 - 3 1 3-53 .18 Concord River, at Concord .0047 .0158; 1.80 1.42 3.22 ! .20 Concord River, at Lowell .0027 .OO97 2.85 1.59 4-44 I .26 Neponset River, at Readville .0027 .0158 I.4O 1.98 3-38 ) .29 Neponset River, below Hyde Park. .0064 .0175 2.IO 1.77 3-87 1 .30 104. Ratios of Standard Gallons. — A portion of tlis above analyses were found with their quantities of im- purities expressed in grains per imperial gallon, a British standard measure containing 70,000 grains, and some of them expressed in parts per 100,000 parts. They have all been, as have those following, reduced to grains in a U. S. standard gallon, containing 58372.175 grains. The degrees of hardness are expressed by Clark’s scale, which refers to the imperial gallon. * Selected from the Fifth Annual Report of the Mass. State Board of Health. ANALYSES OF WELL WATERS. 121 The other quantities may be easily reduced to equiva- lents for imperial gallons, by aid of logarithms of the quan tities or of the ratios : Imperial gallon — No. of grains 70000 Logarithm, 4.845098 U. S. gallon — No. of grains 58372.175 Ratio of imp. to U. S. gallon 1.199201 “ of U. S. to imperial gallon 833886 “ of cubic foot to one imp. gallon. . . 6.23210 “ “ “ “ “ “ U. S. “ . . . 7.48052 “ “ one imp. gall, to one cu. ft 16046 “ “ “ U.S. “ “ “ “ “ 13368 4. 766206 0.078892 1.921108 0.794634 0.873932 1.205367 1.126066 The following analyses of various well waters are in a more condensed form : TABLE No. 35. Analyses of Water Supplies from Domestic Wells. (Quantities in Grains per U. S. Gallons.) Wells. Mineral Matters. Organic Matters. J £ < 2 h j 0 C He n Hardness, Clark’s Scale. Albany, Capital Park 65.20 “ Lvdius Street 19.24 “ average of several 48.69 Boston, Beacon Hill 50.00 “ Tremont Street 26.60 “ Long Acre 56.80 “ average of three 44.46 “ Old Artesian 54-35 1.85 55.20 Brookline, Mass 9.89 4.08 13-97 Brookl}-n, L. I 45.40 “ average of several 48.83 Charlestown, Mass 26.40 Cape Cod TO . 01 2.41 12.42 Detroit, Mich 116.46 Dayton, Ohio 56.50 Dedham, Mass., Driven Pipe 5-12 1. 12 6.24 “ “ Artesian 4.08 1 .11 5.19 Fall River, Mass., average of seventeen.. 25.16 7.00 32.16 12.17 Hartford, Conn., No. 1 19-33 8-39 “ “ No. 2 32.16 13-44 “ “ No. 3 37 -io “ “ No. 4 “ “ No. 5 43 - 60 69.05 io -55 19.22 122 IMPURITIES OF WATER. Analyses of Water Supplies from Domestic Wells — ( Continued ) Wells. Mineral Matters. Organic Maimers. Total Solids. Hardness, Clark's Scale. Indianapolis, Ind 60 OO Lowell, Mass., average of fifteen 39-33 8.71 London, Eng., Leadenhall Street 90.38 9-59 99-97 .... “ “ St. Paul’s Churchyard. .. . 62.54 Lambeth, “ 83-39 Lynn, Mass 34.08 Manhattan, N. Y 104 . 00 “ average of several 49.00 New Haven, Conn., average of five New York, west of Central Park 38.95 4-59 20.32 43-54 “ average of several 58.00 Newark, N. J., average of several 19.36 Providence R. I., average of twenty-four. 24.05 8.82 33-02 IO.87 “ “ purest of “ 7.76 3-35 II. II 7.70 “ “ foulest of “ 56.99 24.12 81. 11 22.26 Portland, Me., average of four 13-35 5-13 18.48 Pawtucket, R. I 29. 16 3 - 03 32.19 “ “ 25.08 3-73 28 . 81 “ “ 18.68 3-62 22.30 Paris, France, Artesian 9.86 Rochester, N. Y., average of General 30.00 Rye Beach, N. H 6.08 2-43 8.51 Springfield, Mass 7.82 2.03 9-85 8.81 2.01 10.82 <( ti 11-53 1. 91 13-44 It U 14-83 3- 08 17.91 Schenectadv, N. Y., State Street 46.88 2-33 49.21 Taunton, Mass 20.14 2.98 23.12 “ “ 39-86 4.09 43-95 Waltham, “ 7.68 4.08 11.76 “ “ Pump 17-79 7.46 25.25 Winchester, “ 4.00 2.40 6.40 “ “ 8.00 2.40 10.40 “