Issued October 23 i9iS 
 
 '' S. DEPARTMENT OF AGRICULTURE, 
 
 GB 1205 WEATHER BUREAU. 
 
 .U6 ' CHARLES F. MARVIN, Chief. 
 
 1915 
 
 Copy 1 
 
 INSTRUCTIONS TO 
 
 SPECIAL RIVER AND RAINFALL 
 OBSERVERS. 
 
 ALFRED J. HENRY, 
 
 Professor of Meteorology. 
 
 WASHINGTON: 
 
 GOVERNMENT PRINTING OEFIOE. 
 
 1915. 
 
Issued October 23, 1915: 
 
 U. S. DEPARTMENT OF AGRICULTURE, 
 
 WEATHER BUREAU. 
 CHARLE^ F. MARVIN, Chief. 
 
 INSTRUCTIONS TO 
 
 SPECIAL RIVER AND RAINFALL 
 OBSERVERS. 
 
 ALFRED J. HENRY, 
 
 Professor of Meteorology. 
 
 WASHINGTON: 
 
 GOVERNMENT PRINTING OTTIOE. 
 
 1915. 
 
x-^' 
 
 Qi^%^ 
 
 ^^ 
 
 D. of D. 
 NOV 6 1915 
 
i. 
 
 
 NOTE TO OFFICIALS IN OHAEGE OF DISTKICT OENTEES. 
 
 In general the instructions for Weather Bureau officials in charge 
 of river district centers will be found in Station Eegulations, There 
 has been included in this pamphlet, however, some matter that is 
 closely related to the work of the district center, yet is scarcely 
 appropriate to Station Eegulations, as, for example, the paragraphs 
 on rain gage and on river gages in general. 
 
 Special attention is directed to the insert sheets at the end of the 
 pamphlet. These sheets are designed to carry the specific instruc- 
 tions from the district center to the river or rainfall observer as to 
 when to use- the telegraph, etc. It is expected that each district cen- 
 ter will complete a set of insert sheets for every river or rainfall 
 observer in his district and attach the sheets to the gummed stubs at 
 the end of the pamphlet. A duplicate set should be retained at the 
 district center and additional specific instructions may be added 
 from time to time by forwarding new insert sheets. 
 
 NOTE TO EIYEE AND EAINFALL OBSEEVEES. 
 
 This book of instructions will be carefully preserved. When an 
 observer is relieved he will turn it over to his successor, obtaining 
 the latter's receipt therefor, which will be forwarded by mail to the 
 official in charge of the district. 
 
LIST OF ILLUSTEATIONS. 
 
 1. An 8-incli rain gage. 
 
 2. Rain gage and box support. 
 
 3. Vertical staff gage, 
 
 4. Inclined river gage. 
 
 5. Vertical gage painted on a bridge pier. 
 
 6. Enameled scale gage. 
 
 7. Chain and weight gage, short box pattern. 
 
ik. 
 
INSXRUCTIONS. 
 
 FOR 
 
 SPECIAL KIVER AND RAINFALL OBSERVERS. 
 
 OBJECT OF RIVER AND RAINFALL OBSERVATIONS. 
 
 The river and rainfall stations of the AVeather Bureau are main- 
 tained j)rimarily for the purpose of giving warning of the approach, 
 magnitude, and duration of high waters, and for forecasting water 
 stages at all heights, in the interest of navigation on the inland water- 
 ways of the country. The river and precipitation data are also of 
 great value to various other interests, particularly to those concerned 
 with the problems of irrigation and water supply. 
 
 DISTRICT CENTERS. 
 
 For the better supervision and control of the work, the special 
 stations are arranged in districts. These districts are under the direc- 
 tion of officials at regular meteorological stations of the Weather 
 Bureau, designated as district centers. 
 
 All correspondence relating to the work of substations, such as the 
 furnishing of supplies, renewal of gages, settlement of accounts, and 
 emplo3^ment of observers, should be conducted through the official in 
 charge at the district center to which the station is assigned. In the 
 case of a combined station the official in charge of the river district 
 will communicate direct with the station on matters connected with 
 river work, but he will furnish copies of all important correspondence 
 to the section director or other official who is also concerned in the 
 work of the combined station. 
 
 Persons accepting positions as special river and rainfall observers of 
 the Weather Bureau become authorized agents of the United States, and 
 are amenable to the laws in case of neglect of duty. 
 
 Records of river stages. — The records of stages are preserved at 
 Washington and printed from time to time. They are accessible at 
 Washington, T>. C, river district centers, and at Weather Bureau 
 stations in the larger cities. 
 
 SUPPLIES. 
 
 Supplies of blank forms, franked and addressed envelopes, rain 
 
 gages, measuring sticks, and other necessary supplies are furnished 
 
 7 
 9424—15 2 
 
8 lisrsTEucTioisrs to special eiver and eaiitfall obseevees. 
 
 to observers upon application to the official in charge of the district 
 center. Timely requisition will be made for such supplies as are 
 needed, and the needs of the station must be so anticipated as to 
 allow ample time for the delivery of the articles from the Central 
 Office at Washington, D. C, through the district center. One month 
 is usually sufficient for this. • 
 
 PROPERTY. 
 
 If the river gage is the property of the Weather Bureau, it is 
 under the direct care of the river observerj but it will not be repaired 
 or changed in any manner without the consent of the official in charge 
 of the river district. 
 
 Advise the district center whenever the gage needs repairs. It is 
 important that the gage be kept in good repair and well painted. 
 
 Advise the district center promptly, by telegraph, if serious, of 
 any damage to the gage that affects the accuracy of the readings. 
 
 If the gage is not the property of the Weather Bureau, it is im- 
 portant that the observer inform the district center of any repairs or 
 changes made or when repairs are necessary. 
 
 "Wlien property and supplies are furnished to an observer, an item- 
 ized receipt therefor will be immediately mailed to the official in 
 charge of the district. 
 
 When an observer is relieved from charge of a station, he will 
 make out a list in triplicate of all Government property in his pos- 
 session, and append at the bottom thereof the following certificate : 
 
 (Date) , 19—. 
 
 I certify that I have this day received from (name of former 
 
 ohserver) tlie above-mentioned articles in good condition unless otherwise speci- 
 fied hereon. 
 
 {Name of neiv observe)-) . 
 
 One copy of this report will be mailed to the official in charge of 
 the district, one given to the new observer, and the third retained by 
 the retiring observer. 
 
 Wlien from any cause any article of property becomes unserviceable 
 or in need of repairs, the fact must be at once communicated to the 
 official in charge of the district for such action as he may deem proper 
 and necessar}^ 
 
 INSTRUCTIONS. 
 
 The duties of a river observer consist in noting on a form furnished 
 for the purpose — 
 
 First. The height of water on the gage, with change in 24 hours. 
 Second. Depth of rain or melted snow, with times of beginning 
 and endinef. 
 
INSTRUCTIONS TO SPECIAL KIVEB AND RAINFALL OBSERVERS. 9 
 
 Third. Actual depth of snow, if any, since last observation. 
 
 Fourth. Direction of wind. 
 
 Fifth. State of weather. 
 
 Sixth. Depth of snow, if any, on ground on 15th and last day of 
 
 month; also date on which last snow of season disappeared. 
 Seventh. Stage of river at crest of each flood, with hour of day, 
 should it not occur at time of regular observation. 
 Detailed instructions as to the manner of keeping the records of 
 river stages and the weather will be found on the back of Form 
 No. 1006-Met'l. 
 
 A postal card — Form 1049-Met'l — must be carried to the river 
 gage and the readings entered thereon as soon as made. On the last 
 day of the month this card, which is the original record of the daily 
 stages of water in the river, will be mailed to the district center, 
 except that the following stations will forward the form to the cen- 
 tral office at Washington: Keokuk, St. Louis, Memphis, Vicksburg, 
 New Orleans, Cincinnati, Cairo, Nashville, Johnsonville, Kansas 
 City, Little Eock, and Shreveport. 
 
 Telegraphic reports are also made under certain special conditions, 
 as hereinafter described. 
 
 Rainfall ohservers. — The duties of a rainfall observer consist in 
 noting on a form furnished for the purpose — 
 
 1. The depth of rain or melted snow, with times of beginning and 
 ending. 
 
 2. Actual depth of snow, if any, since last observation. 
 
 3. Direction of wind. 
 
 4. State of weather. 
 
 5. Depth of snow, if any, on ground on 15th and last day of 
 month. 
 
 Telegraphic reports are also made under certain conditions, as 
 hereinafter set forth (see insert page at end of pamphlet). 
 
 FORMS FOR RECORDING OBSERVATIONS. 
 
 Form 1006^ Mefl. — The record of the observations made at the 
 station for the month should be filled up in accordance with the 
 instructions printed on the back of the form. 
 
 The form should be mailed to the official in charge of the district 
 center on the first day of the succeeding month. 
 ' Before mailing, a copy must be made by the observer in the book 
 furnished for that purpose. 
 
 At stations supplied with books of Form 1006, Met'l, on thin 
 (onion-skin) paper, three copies of the form will be prepared. 
 The first two or top copies of the form will be mailed to the district 
 center and the last copy will be left in the book and will constitute 
 
10 INSTRUCTIONS TO SPECIAL RIVER AND RAINFALL OBSERVERS. 
 
 the retained record of the river station. (Four or five copies can be 
 prepared by using a hard indelible lead pencil, if special conditions 
 at a station should require more than three.) 
 
 The descriptive data at the head of Form lOOG-Met'l will be care- 
 fully entered each month and will be verified at the district center; 
 particular care being taken to see that the name of the station, 
 month, and year, and name of the observer are properly entered. 
 Means will not be computed for less than 15 days. 
 
 Form 3021i.^ Tel. — For telegraphing reports in accordance with 
 instructions hereinafter given. 
 
 Form, lOSJfi Mefl {postal card). — For reporting the daily observa- 
 tions to the official in charge of district center or to other officials 
 when required. 
 
 TELEGRAPHIC REPORTS. 
 
 As a general rule, whether or not river stages will be telegraphed 
 to the district center daily depends on the value of the reports, 
 either for the purpose of issuing flood v.^arnings or in the interests 
 of navigation. Instructions as to when the telegraph or telephone 
 shall be used will be found on the insert sheets at the end of this 
 j)amphlet. 
 
 . In telegraphing a report of heavy precipitation to the district 
 center the telegram should be sent immediately when the heavy rain 
 ceases. Do not wait until the time of the regular daily telegram. 
 At stations telegraphing daily the morning telegram should include 
 the total 24-hour rainfall, although a part of it may have been re- 
 ported in a special observation. 
 
 Telegraphic reports will contain the fullest information possible 
 within a limit of 20 words, including the address and signature. 
 
 Reports for telegraphic transmission will be written on Form 
 8024 Tel., in the following order : First, the word " observer " ; sec- 
 ond, name of the place to which the report is to be telegraphed; 
 third, name of station from which report is telegraphed ; fourth, time 
 of observation, if other than the time of the regular morning ohserva- 
 tion; fifth, stage of river ; sixth, tendency of river, as " rising," 
 " falling," " stationary," as the case may be ; seventh, state of 
 weather, " clear," " partly cloudy," " cloudy," " raining," " sleeting." 
 "snowing"; eighth, depth of rainfall; ninth, depth of unmelted 
 snow, in inches (in case of no precipitation, add the word "none") ; 
 tenth, special remarks, such as " floating ice," " heavy loss of crops 
 and stock," " frozen," or any other information of value ; eleventh, 
 surname of the observer. 
 
 Reports of regular morning observations should not contain the 
 time word in the telegram. 
 
IISrSTRUCTIONS TO SPECIAL EIVER AND RAINFALL OBSERVERS. 11 
 
 The direction of the wind will not be sent, unless specially called 
 for by the official in charge of the district center. 
 
 The rising or falling tendency of the water should indicate the 
 condition at the actual time of the observation and not with reference 
 to the preceding observation. For instance, the river may have been 
 rising for several days and it may be higher than at any preceding 
 regular observation, but it may have started to fall. In such an 
 event telegraph " falling." 
 
 The reports should be carefully and legibly written in letters that 
 can not be misunderstood. Observers are advised to write messages, 
 whenever possible, in print letters instead of a running hand. The 
 actual stage of the river in feet and tenths of a foot will be spelled 
 out, as " twenty-four feet six," " twenty feet two," etc. ; the rainfall 
 in inches and hundredths of an inch will be spelled out, as " one 
 inch twenty-two," " three inches five," etc. The word " rising " or 
 " falling," coming between the stage of vv^ater and the amount of 
 rainfall, will prevent mistakes by confusing the tenths of a foot with 
 the inches of rainfall. When less than 1 inch of rainfall is to be 
 reported, the word " hundredths " should be added, as " seventy-four 
 hundredths," " six hundredths," etc. 
 
 Messages should be filed at the telegraph office as soon as prac- 
 ticable after the observation has been taken. One copy of the tele- 
 gram will be given to the operator at the telegraph office and one 
 copy retained by the observer. 
 
 The following are examples of telegraphic reports : 
 
 1. Telegram from an observer who reports each morning by tele- 
 graph : 
 
 Hermann, Mo., March 1, 1915. 
 Observek, St. Louis, Mo.: 
 
 Hermann, sixteen feet three statiouray clear none. 
 
 Jones. 
 [Translation.] 
 
 Observer, St. Lonii?, Mo Address of Weather Bureau observer at St. 
 
 Louis, Mo. 
 
 Hermann Name of river station at Hermann, Mo. 
 
 Sixteen feet three Stage of river, 16.3 feet. 
 
 Stationary River stationary at time of observation. 
 
 Clear State of the weather. 
 
 None No precipitation. 
 
 Jones Surname of river observer. 
 
 2. Telegram from an observer taken at a time other than the regu- 
 
 Apkil 30, 1914. 
 
 lar morning observation hour 
 
 Observer, Memphis, Tenn.: 
 
 Helena two p. m. minus two feet eight falling clear none. 
 
 Brown. 
 
12 iisrsTEUCTioisrs to special eiver and eainfall observers. 
 
 [Translation.] 
 
 Observer, Memphis, Tenn Address Weatlier Bureau observer at Memphis, 
 
 Term. 
 
 Helena Name of river station at Helena, Ark. 
 
 Two p. m Time of observation, 2 p. m. 
 
 Minus two feet eight Stage of river, —2.8 feet, or 2.8 feet below the 
 
 zero mark on the gage. 
 
 Falling River falling at time of observ^ation. 
 
 Clear State of weather. 
 
 None No precipitation. 
 
 Brown Name of river observer. 
 
 3. Telegram containing regular morning observation, with infor- 
 mation as to crest of flood: 
 
 Maech, 20, 1914. 
 
 Observee, Memiiliis, Tenn.: 
 
 Helena forty one feet two cloudy one inch two highest forty one feet sis 
 about 8 p. m. 
 
 Beown. 
 [Translation.] 
 
 Observer, Memphis, Tenn Address Weather Bureau observer at Memphis, 
 
 Tenn. 
 
 Helena Name of river station at Helena, Ark. 
 
 Forty one feet two Stage of river, 41.2 feet. 
 
 Cloudy State of weather. 
 
 One inch two i Precipitation, 1.02 inch. 
 
 Highest forty one feet six Crest of flood, 41.6 feet. 
 
 About 8 p. m Crest occurred about 8 p. m. 
 
 Brown Name of observer. 
 
 4. Telegram from an observer who does not send daily observations 
 by telegraph: 
 
 Apeil 3, 1915. 
 Obseevee, Cincinnati, Ohio: 
 
 Charleston 10 a. m. twenty nine feet three rising rapidly snowing thirty two 
 hundredths ice gorge half mile below. 
 
 Jones. 
 [Translation.] 
 
 Observation taken at 10 a. m. 
 Stage of river 29.3 feet ; rising rapidly. 
 Snowing; precipitation 0.32 inch. 
 Ice gorge half mile below. 
 Jones, river observer. 
 
 5. Telegram from an observer who does not send daily observations 
 by telegraph: 
 
 Apeil 7, 1915. 
 Obseevee, Pittsburgh, Pa.: 
 
 Sharon 8 a. m. nine feet two rising rapidly raining two inches twelve bottoms 
 beginning to flood. 
 
 Beown. 
 
INSTRUCTIONS TO SPECIAL EIVER AND RAINFALL OBSERVERS. 13 
 
 [Translation.] 
 
 Observation taken at 8 a. m. 
 Stage of river 9.2 feet ; rising rapidly. 
 Raining; precipitation 2.12 inches. 
 River bottoms beginning to flood . 
 
 Special observations. — Special observations will be made in ac- 
 cordance with the instructions on the insert sheets in the back of this 
 pamphlet. They will be prepared according to the instructions on 
 page 12, examples 4 and 5. 
 
 A statement of all observations telegraphed will be entered on 
 Form 1006, under " remarks," giving the day and the hour taken. 
 Failure to record extra observations or the fact that observations were 
 telegraphed for which compensation is claimed will necessitate sus- 
 pending payment until the discrepancies are explained. 
 
 ^Yith each important rise it is desired to have a special observation 
 at the time of the highest water. If this can not be done, but the 
 highest point reached by the river can be determined, -it is desired 
 that this be entered on Form 1006, giving the approximate time it 
 occurred. In case the exact time of crest is not knovv^n, always enter 
 "Approximately " after the time given. 
 
 Observations inissed. — Eegular morning observations missed will 
 be deducted from the pay roll unless satisfactorily explained. The 
 Chief of the Weather Bureau reserves the right to withhold pay- 
 ment from any person xA\q persistently neglects to make his reports 
 accurately and forward them promptly. Payment will be made 
 quarterly. 
 
 Observers should, when possible, have substitutes capable of per- 
 forming all the duties of a river observer in order that there may be 
 no interruption of the work in case of sickness or unavoidable absence 
 from, the station on the part of the regular observer. Members of the 
 observers' families are very often instructed in the work. 
 
 RAIN GAGE. 
 EXPOSURE OF RAIN GAGE. 
 
 The exposure of the rain gage is a very important matter. The 
 most serious disturbing effect in collecting rainfall is the wind. In 
 blowing against the gage the eddies of wind formed at the top and 
 about the mouth of the gage carry the rain away, so that too little 
 is caught. 
 
 Observers will take particular care in selecting a good place for the 
 location of a gage, as the value of the records is sometimes greatly 
 
14 IITSTEUCTIONS TO SPECIAL EIVER AND EAINPALL OBSERVEES. 
 
 impaired by improper exposure. It is scarcely necessary to say that 
 every precaution should be taken to protect gages from the interfer- 
 ence of animals and unauthorized persons. Select, if possible, a 
 position in some open lot as unobstructed as possible by trees, build- 
 ings, or fences. Such a place, in general, affords the best exposure. 
 
 IIVSTRUCTIONS FOR THE USE OF THE RAIN GAGE. 
 
 Descnption of gage. — The rain gage consists of the following parts : 
 The receiver A; the overflow attachment B ; the measuring tube C. 
 
 The top cylindrical portion of the receiver, marked «, see fig. 1, is 
 exactly 8 inches in diameter inside and is provided with a funnel- 
 shaped bottom which conducts any precipitation falling into the 
 receiver into the tall cylindrical measuring tube C, the total height of 
 which, inside, is exactly 20 inches. The diameter of this tube is much 
 smaller than the large receiving tube «, being only 2.53 inches. In 
 consequence of this a small amount of rain falling into the receiver 
 and flowing into O fills the latter to a depth greater than the actual 
 rainfall in proportion as the area of the receiver is greater than the 
 area of the measuring tube. In the standard gages of the Weather 
 Bureau the depth of the rainfall, in accordance with this principle, is 
 magnified just 10 times. The receiver A has a sleeve J, figure 1, 
 which slips over the tube C, and very effectually prevents any loss of 
 rainfall. Again, when the rainfall is very heavy the tube G may be 
 more than filled. In this case, to still prevent loss, a little opening, 
 shown at e, figure 1, is made in the sleeve fZ, just on a level with the 
 top of the tube 6'. 
 
 The excess of rainfall escapes through this opening, and is retained 
 in the large overflow attachment B^ and can be measured afterwards, 
 as will be described below. The diameter of the overflow attachment 
 in the latest style gages is now made just 8 inches inside diameter. 
 The object of this is to be able to use this portion of the instrument as 
 a snov/ gage, as will be explained hereinafter. 
 
 RAIN GAGE AND SUPPORT. 
 
 The box in which the gage is shipped to the observer is expressly 
 designed as a stand for the instrument, and should be opened at the 
 head, which is fastened by screws. Set the box up as nearly vertical 
 as possible at the place selected for the exposure, and secure it in this 
 position by driving down four stakes alongside, in the manner indi- 
 cai,ed in figure 2. Care must be taken to have the gage in a truly ver- 
 tical position. Slip in the head and lower it to the level of the screw 
 
INSTEUCTIONS TO SPECIAL EIVEE AND RAINFALL OBSEEVEES. 15 
 
 holes in the sides of the box about 10 inches from the bottom, where 
 the head will be securely fastened with the screws taken out in open- 
 
 Ji-xmt Vi-ezo. 
 
 VerticaZ Sccttan^ 
 
 \ "i 
 
 X^ -4 
 
 y'l 
 
 V--^ 
 
 { 
 
 i 
 
 "e 
 
 P 
 
 n 
 
 C 
 
 B 
 
 
 
 
 
 
 
 Receiver. 
 
 ffiPflT 
 
 1 . 
 
 i!!,.,.,,...,.i^. 
 
 1 
 
 -"mm 
 
 
 il. 
 
 i-. 
 
 Sfortzontdl s<ectiaTv,E-F. 
 
 O 12 3^56 7 8 9 W // /Z IJ 14 15 16 17 /3 /3 20ZIZZ23 a^ INCHES 
 SCALE. 
 
 Fig. 1. — Rain gage. 
 
 ing the box. The gage can now be placed inside, and appears as 
 shown in figure 2. 
 
 TO HIIj:ASURE rainfall AftD SNO\%rFAl,l,. 
 
 EAINFALL. 
 
 The rain-gage measuring stick is graduated into inches and tenths 
 of inches. Kemembering that the actual depth of the rainfall is mag- 
 nified 10 times, as explained above, it is plain that if we find the water 
 10 inches deep in the measuring tube the real rainfall must have 
 been only 1 inch deep ; or if the water in the tube is onty one-tenth 
 inch (or, written as a decimal, 0.1 inch deep) the rainfall must have 
 been only one one-hundredth inch (or, written as a decimal, 0.01 
 inch). 
 
 To save observers the trouble of always thinking about the mag- 
 nification, and to avoid possible errors in reports, the numbers on 
 the graduations of the measuring sticks are not actual inches, but 
 have all been divided by 10, and thus represent the actual rainfall. 
 Moreover, these numbers are expressed in hundredths of inches of 
 
16 INSTEUCTIOlSrS TO SPECIAL EIVEE AND EAIjSTFALL OBSEEVEES. 
 
 rainfall, and are written as decimal fractions. Thus the 10-inch 
 line is numbered 1.00 (read one and zero hundredths), which is the 
 depth of rainfall in inches corresponding to 10 inches of water in 
 the measuring tube; similarly the 1-inch line is numbered 0.10 (read 
 ten one-hundredths) , which again is the depth of rainfall in inches 
 corresponding to 1 inch of water in the tube. 
 
 The depth of the water is measured by inserting the measuring 
 stick into the gage through the small hole in the funnel. When the 
 stick reaches the bottom of the measuring tube it should be held for 
 one or two seconds and then quickly withdrawn and examined to see 
 
 at what division of the graduation the 
 top of the wetted portion comes. The 
 numbering of this division, as stamped 
 on the stick, gives, as has just been 
 explained, the actual depth of rainfall, 
 and in making out records and reports 
 observers should always use the decimal 
 expressions. Of course, it will rarely 
 happen that the top of the wetted por- 
 tion v<'ill fall exactly upon one of the 
 numbered lines — it will generally be on 
 or near one of the shortest lines. Thiis. 
 for example, suppose the watermark 
 comes to the sixth short line beyond 
 the line numbered 0.80, the proper rec- 
 ord to make in this case would be 0.86- 
 inch rainfall. The number of short 
 lines, reckoned from the numbered line 
 next lower, are alwaj^s to be inserted in 
 place of the in the stamped numbers. 
 Observers should always be careful to 
 put the stick into the gage so that the 
 end at which the numbering begins goes 
 to the bottom and the stick passes through the middle of the tube ; 
 for if the stick is placed near the sides the water is sometimes drawn 
 up by capillary action into the narrow space between the stick and 
 the tube so as to wet the former entirelj^ too high and give A'ery 
 erroneous records. 
 
 After measuring and recording in this way the precipitation found 
 in the gage the top should be removed, the measuring tube emptied 
 and drained, and the gage put in position again. Observers should be 
 careful after emptying the gage to replace the measuring tube so that 
 the bottom stands within the rina; in the middle of the bottom of the 
 
 Fig. 2. — Rain gage and support. 
 
INSTRUCTIONS TO SPECIAL EIVER AND RAINFALL OBSERVERS. 17 
 
 overflow, and in putting on the receiver to see that it passes over the 
 measuring tube and rests squarely down upon the overflow. 
 
 When the amount of rain that has fallen more than fills the measur- 
 ing tube, some care is required to determine the total rainfall. First, 
 carefully remove the receiver so as not to spill any of the water in the 
 measuring tube, which should be exactly full. If some water has 
 been slopped out and the measuring tube is not exactly full, the 
 amount of water remaining must be accurately measured with the 
 stick as already described. The tube is then lifted out slowly and 
 carefully, if full, so as not to spill any of the water into the overflow, 
 emptied, and allowed to drain a moment or so. The water remaining 
 in the overflow^ is then poured into the measuring tube, care being 
 taken not to lose an}^, and measured in the usual way. Suppose this 
 is found to be 0.4T inch rainfall, then, remembering that the measur- 
 ing tube contains just 2 inches, the total rainfall will be 2 inches plus 
 0.47 inch=2.4T inches. Or, in case some water was spilled from the 
 measuring tube, the 0.47 inch should be; simply added to the first 
 measured amount to give the total rainfall. 
 
 SNOWFALL. 
 
 During the winter season, especially in those climates where the 
 precipitation is nearly all in the form of snow, only the overflow 
 attachment will be exposed in the support as a snow gage, removing 
 the receiver and measuring tube to the house. These parts can not 
 be used for measuring snow, and even if rain should occur it would 
 be very apt to freeze and injure the measuring tube. 
 
 When the overflow collector is unprotected from the Avind its catch 
 represents the true amount of snow only in the case of iDrecipitation 
 during calms or very light winds. On windy occasions the catch is 
 often highly inaccurate; the true quantity must be found, if pos- 
 sible, by measuring a section of the freshly fallen snow cut out by 
 forcing the overflow, mouth downward, through the layer and then 
 slipping a thin board or sheet of metal underneath so as to separate 
 and lift up the section of snow thus cut out. 
 
 Assuming that a representative quantity of snow has been obtained 
 in the overflow, a measurement may be secured by placing the vessel 
 in a warm room until the snow has melted and then measuring the 
 water in the measuring tube in the usual way. 
 
 The method just described is objectionable, owing to the time re- 
 quired and to the loss of the snow or water hj evaporation. The 
 following plan is much better : Take the overflow into the room and 
 pour into it one measuring tube full of water to the trim, preferably 
 warm. In cases of deep snowfall more water will be required. This 
 
18 TlSrSTETJCTIOlSrS TO SPECIAL EIVER AIsTD EAIjSTPALL OBSERVERS. 
 
 will melt, or at least reduce to a fluid slush, a considerable amount 
 of snow. The measuring tube should then be filled to the brim from 
 the melted contents of the overflow and emptied, thereby discarding 
 a quantity of water equal to that added. The remaining water in 
 the overflow, when measured in the tube, then gives the actual depth 
 of melted snow. 
 
 In addition to this measurement by the gage a measurement will 
 be made of the actual depth in inches of the snow on the ground. 
 Select a level place of some extent, where the drifting is least pro- 
 nounced, and measure the snow in at least three places. The mean 
 of these measurements will give the snowfall, which is to be entered 
 in the column of the report headed " Depth of snowfall in inches." 
 Whenever it is impracticable to melt the snow as described in the 
 preceding paragraph, one-tenth of this mean will give an approxi- 
 mate value, in water, for the snow which could not be melted. This 
 value must be set down in the proper column of the report in pre- 
 cisely the same manner as rainfall or snow melted in the gage. 
 After snowfall has once been measured, the same snow should not 
 be measured at subsequent observations. Any fresh snow, however, 
 should be measured and recorded. 
 
 Observations of rainfall should be made at the time of river obser- 
 vations, and the gage should be emptied of all the water it may 
 contain as soon as it has been measured. 
 
 If no rain, snow, or hail has fallen during the period of observa- 
 tion, make the entry ".00 " in the proper column. If the amount is 
 too small to measure, make the entry " Trace " or " T." 
 
 It is particularly important, in the interest of accuracy, that the 
 observations be recorded as soon as made and that the daily entries 
 be made each day. Even if no rain has fallen, the observer should 
 bear in mind that his official record of that fact is very important. 
 
 RIVER GAGES. 
 
 A river stage is the vertical height of the water flowing in a 
 stream above or below a definite plane called the zero of the river 
 gage. A river gage is a device for determining that height. It is 
 very important that the zero of the gage be determined with great 
 care. The best plane of reference is the bottom of flowing water in 
 the stream. This point can be easily determined when there is a bar 
 below the gage, since when the river is at a low stage there will be 
 very little or no water flowing over the bar. The depth of water 
 over the bar at the lowest point should be ascertained by soundings 
 and the zero of the gage made to correspond thereto. In the absence 
 of a bar it will be necessary to make a series of cross sections, or 
 soundings, at and near the point selected for the gage, with a view of 
 
INSTRUCTIONS TO SPECIAL EIVER AND RAINFALL OBSERVERS. 19 
 
 determining the slope of the bottom of the river bed for a short dis- 
 tance both above and below that point. 
 
 When a gage is once established and a long record of readings has 
 been made, it is not advisable to make any change in zero. In no 
 case will the zero of a river gage be changed without the previous 
 approved of the central office. The greatest care should be taken 
 to maintain the absolute stability of all river gages. They should be 
 carefully inspected from time to time with a view of discovering any 
 possible changes due to settling, deviation from the perpendicular, 
 stretching of chains and tapes, etc. 
 
 Bench marks. — For the purpose of ascertaining any changes that 
 may occur in the level of the zero of a gage or any of its marks, 
 from causes described above, a bench mark should be established 
 close by the gage or somewhere in its immediate vicinity. A bench 
 mark consists of some accessible, presumably permanent, point or 
 surface, the difference in level between which and the zero or some 
 other mark on the gage is known by actual leveling between the two. 
 When this difference is found to vary it is presumed to indicate a 
 corresponding change in the level of the marks of the gage, requir- 
 ing either adjustment of the gage or correction of the readings. 
 Such a difference will be reported immediately upon its discovery 
 to the district center. 
 
 Suggested locations for a bench mark are : The top surface of a 
 large stone in the top course of masonry on a bridge pier. Some- 
 times a bench mark is located in the top surface of a large stone 
 buried in the ground specially for the purpose of establishing a per- 
 manent surface. Prominent surfaces in stone buildings are good 
 places for permanent bench marks. 
 
 A copper bolt or metal plate set in the stone wall of some public 
 building, such as the customhouse, post office, or city hall, is a 
 common device for a bench mark in a large city. 
 
 The river gages used by the Weather Bureau are partly shown in 
 figures 3, 4, 5, 6, and 7. The design best adapted to any particular 
 location will be used in each case. 
 
 The specifications to be followed in procuring bids for the con- 
 struction of these gages are as follows : 
 
 SPECIFICATIONS FOR RIVER GAGE SHOTTI^f IN FIG. 3. 
 
 The river g£ige will be made of sound pine or oak timber, free from 
 knots or shakes, 2 inches in thickness, 12 inches in width, and of such 
 a length as to extend, if possible, from 2 or more feet below the zero 
 point to about 5 feet above the highest known water. The face of 
 the plank upon which the graduations are to be made, and the top, 
 bottom, and sides, will be planed smooth and will receive two coats 
 
20 
 
 INSTRUCTIONS TO SPECIAL EIVER AND RAINFALL OBSERVERS. 
 
 t= 
 
 ^ 
 
 ^ 
 
 6 
 
 ? 
 
 of the best white-lead paint. The face will then be graduated as 
 follows : 
 
 Commencing at the point which will correspond to the zero, gradu- 
 ate the gage both above and below that point in feet and tenths of 
 feet. 
 
 The graduations will be chiseled or burnt into the wood to the 
 depth of about one-eighth of an inch and then 
 given two coats of the best black paint. The 
 marks for whole feet will extend entirely across 
 the face of the gage; those for half -feet one-half 
 the distance across, beginning on the left side, 
 and those for the intermediate graduations one- 
 fourth of the distance across, beginning on the left 
 side. Whole feet will also be shown by the ap- 
 propriate figures, 6 inches in height, on the right 
 side of the gage, and so placed that the marks for 
 whole feet will exactly bisect the figures. The fig- 
 ures will also be chiseled or burnt into the wood 
 to the depth of about one-eighth of an inch, and 
 then given two coats of the best black paint. An 
 enameled plate with the legend " U. S. Weather 
 Bureau " will be fastened at the top of the gage. 
 These can be obtained on stores requisition on the 
 central office. 
 
 Having graduated the gage, select a pile or other 
 stationary object on some portion of the levee, wharf, 
 or bridge pier where the gage is to be installed. 
 LovN-er the gage into the water until its zero is 
 exactly at the point selected as the zero of the river 
 plane, taking care to keep it in a vertical position. 
 Then securely fasten it in this position by spikes 
 or bolts. 
 
 ^ 
 
 2 
 
 SPECIFICATION! 
 
 FOR RIVER GAGE SHOWN IN 
 FIGURE 4. 
 
 Fig. 3. 
 
 Procure a piece of pine, cypress, or oak timber 
 about 6 by 6 inches, and of sufficient length to 
 cover the full range of the river between extreme 
 low and high water marks. This timber will be 
 placed in the river bank, firmly embedded in the earth, leaving 1^ 
 inches exposed above the level of the ground. 
 
 To secure this form of gage thoroughly it will be necessary to 
 attach it to 4 by 6 or 6 by 6 inch oak, cedar, locust, or fir posts, driven 
 
INSTEUCTIOlSrS TO SPECIAL EIVEE AISiD EAINFALL OBSEEVEKS. 
 
 21 
 
 6 feet into the ground, and placed 6 feet apart. The upper edge of 
 the gage should be planed smooth, and a strap of iron, i by 2 inches 
 screwed along the top on the upstream side, and graduated in feet 
 and tenths of feet, after being placed in position, taking the point 
 which has been selected as the zero of the scale, and locating the 
 feet and tenths both above and below that point. The screw holes 
 in the strap of iron, except the one near the middle, should be slightly 
 elongated and there should be about one-tenth inch of space for 
 every 10 feet on length left between the ends where two straps are 
 joined so as to provide for the expansion of the iron without buck- 
 ling. The graduations for this gage will be the same as for the 
 gage shown in figure 3. Especial pains should be taken in graduat- 
 ing the gage to see that the distances marked off upon it for each 
 
 4- feet 
 
 3 . 
 
 ^jci^vme Utah Waier. 
 
 
 
 ^ 
 
 
 
 
 1 1 1 
 1 1 ■ 
 
 i 1 1 
 
 Tidier" Z/ine x ^li^^ 
 
 1 1 I 
 1 1 { 
 
 ■-^r-_;:^:;rr>->>"-:r 
 
 y— 
 
 
 
 r-prjrrrt:z 
 
 ----- ^6,-^--7J^''' 
 
 4^^' y\ i 
 
 '• — 'j,'" i — 1''' 
 
 
 Fig. 4. 
 
 foot and its subdivisions correspond exactly to a vertical foot and its 
 subdivisions of which it is a measure. This should be done by an 
 engineer whenever possible. 
 
 It is also very desirable that this form of gage should have its top 
 surface covered with two coats of the best white lead or zinc paint, 
 with the proper figures opposite the footmarks on the iron strap 
 in black paint and not less than 1 inches in length. Figures should 
 also be burnt in before painting, as permanent markings are thereby 
 secured. 
 
 SPECIFICATIONS FOR RIVER GAGE SHO^SVN IN FIGURE 5. 
 
 Where a stone pier or abutment is available, a very durable gage 
 can be made by dressing a face, 12 inches in width, from extreme low 
 
22 INSTEUCTIONS TO SPECIAL EIVER AND EAINFALL OBSERVERS. 
 
 water to as far above as may be necessary. The dressed surface 
 should be covered with two coats of the best black paint, preferably 
 asphaltum, after all holes and indentations in the pier have been 
 filled with cement. 
 
 Fig. 5. 
 
 The space, both above and below the point at which the zero will 
 be placed, will be graduated with two coats of the best white lead or 
 zinc paint into feet and tenths of feet. Markings for whole feet will 
 extend entirely across the gage ; those for half feet one-half the way 
 across, beginning on the left side; and those for the intermediate 
 graduations one-quarter of the way across, beginning on the left 
 
IIsrSTEUCTIONS TO SPECIAL EIVER AND BAHSTPALL OBSEEVEES. 
 
 23 
 
 side. All markings will be one-quarter of an inch in width. The 
 figures for the whole footmarks will be in white, 5 inches in height, 
 and the center of each figure must be over the foot line at the right. 
 Specifications for an inclined gage of concrete construction should 
 invariably be forwarded to the central office for approval. 
 
 THE ENAMELED SCALE GAGE, 
 
 This form of gage consists of numerals and graduated slabs or 
 sections, which, being screwed upon a supporting timber, form the 
 scale of a vertical staff gage. The advan- 
 tages of the enameled scale are legibility and 
 durability ; it does not tarnish when exposed 
 to the weather, and it may be washed off 
 when mud accumulates on the lower section. 
 The drawing below shows a section of the 
 gage and its support. The width of the 
 graduated section is 4 inches and of the 
 integers 3 inches each ; consequently the sup- 
 port must be 11 inches wide. The support 
 should consist of 2 by 11 inch plank, prefer- 
 ably cypress, dressed on both sides, to be 
 given a coat of raw linseed oil and then two 
 coats of lampblack and oil. When practi- 
 cable, battens of 2 by 4 stuff should be 
 attached to the imderside of the plank, but 
 where the planks must be attached to the 
 side of the pier the battens may be omit- 
 ted. In making requisition for an enameled 
 gage it is necessary to give the range in 
 river stages the gage is to cover. The in- 
 tegers and graduated sections are attached to the timber support 
 by screws. 
 
 Fig. 6. 
 
 CHAIN- AND- WEIGHT RIVEB GAGE, 
 
 SHORT BOX PATTERN. 
 
 The box is 2 feet long, 6 inches wide, 8 inches high on the back, 
 and 5^ inches on the front. The hole for the down spout is in the 
 center of the box, so that the scale may be placed on either side, al- 
 though the scale provided is intended to be placed on the left side 
 of the box. The enameled scale is in five sections, each 2| feet long, 
 and is graduated from 2|- feet below to 10 feet above zero. An inch 
 board of sufficient length should be attached to the bridge rail in 
 
24 INSTEUCTIONS TO SPECIAL EIVEE AND RAINFALL OBSERVERS. 
 
 order to bring the scale out flush with the slot in the end of the 
 gage box. 
 
 The box should be securely fastened by its 8-inch side to the out- 
 side of the guard rail, or side of the bridge, the former preferred. 
 If it should be necessary, a 2 by 8 inch plank of cypress or hard pine 
 will be fastened to the bridge and the gage attached to this. Before 
 attaching the box to the bridge the down spout should be screwed 
 into the underside of the box so that the hole in the pipe is opposite 
 the hole in the back of the box, and the bolt should be put through 
 and bolted on the outside. 
 
 In placing the enameled scale, a careful measurement should be 
 made from the zero of the scale to the 10-foot mark, to see that it is 
 exactly 10 feet. It may be necessary to overlap the sections at the 
 5-foot point slightly in order to do this. 
 
 An open pulley is used in order that the chain and weight may 
 be taken up into the bos after each observation. The weight should 
 be laid in the bottom of the box and the chain carefully piled from 
 end to end of the box, care being taken not to lay the chain across 
 the upper end of the down spout, in order to prevent its being tam- 
 pered with. 
 
 When the zero of the river has been established, the weight will 
 be lowered so that its lower end just touches the zero point. The 
 link of the chain directly opposite the zero mark on the scale will 
 then have a rivet put into it and flattened on both sides, so that it 
 will remain firm. Should it be necessary to record river readings 
 beyond the scale limits, the rivet in the chain will be drawn up 
 so that it will be exactly opposite the highest footmark on the scale. 
 Another rivet will be placed in the link of the chain exactly oppo- 
 site the zero mark of the scale, and readings taken, using this 
 second rivet as a base. A third rivet can also be added, if necessary. 
 In recording readings which are beyond the scale limits, the second 
 or third rivet will be used as a zero mark instead of the first, and 
 there will be added to the observed reading the distance between 
 the rivets — 10, 20, 30 feet, etc., as the case may be. The weight 
 is provided with an adjustable eyebolt, by which any slight error 
 in the placing of the rivet may be corrected. The nut on the bolt 
 should then be firmly tightened, to prevent any change. If left 
 loose the weight is liable to get out of adjustment and thus cause 
 an error in the readings. 
 
 In making requisition for gages officials in charge of river dis- 
 tricts will state the length of chain required. 
 
 The box attachments are sent complete and the only materials 
 to be supplied at the station are the bolts or screws for attaching 
 
IlSrSTRUCTIONS TO SPECIAL EIVEE AND EAINFALL OBSEEVEES. 25 
 
 the box to the bridge, and a board and plank, when needed. Figure 
 7 shows the chain and weight gage in place. 
 
 DESCRIPTION OF THE MOTT RIVER GAGE. 
 
 Br)x. — The gage box and doors are constructed of sand-dried oak 
 lumber dressed on all surfaces, |-inch stock, and inside dimensions as 
 follows: Height, 18 inches; width, 18 inches; depth, 1\ inches. 
 
 Boors. — The box has two doors secured with extension hinges in 
 such manner as to permit the doors to swing back against the sides of 
 the galvanized-iron box. The entire outside surface of the box, 
 excepting the bottom, and including the doors, is covered with No. 24 
 galvanized iron. The joints of the galvanized-iron cover are lapped 
 and soldered, making the cover water-tight. The galvanized-iron 
 cover of the box is painted with two coats of dark-green mineral 
 paint, with a label on the doors of the box bearing the words " Prop- 
 erty United States Weather Bureau. Penalty for Interference." 
 
 Lock. — The box is fitted with a brass mortise lock, using the same 
 key as is used in the standard padlock for the chain and weight gages 
 of the United States Weather Bureau and United States Geological 
 Survey. 
 
 Mechamsin. — The box is fitted with a tape reel consisting of an 
 aluminum brake wheel and a brass spider, mounted on a turned cast- 
 iron standard and fitted with a wooden handle. A leather brake strap 
 and suitable levers for releasing the brake are provided. The brake 
 strap is attached to a brass coil spring of sufficient strength to hold 
 the weight and tape in any position. An iron guide wheel running 
 on a turned axle, secured in the box by a cast-iron standard, is also 
 provided. 
 
 Taye and gage. — The tape is made of phosphor bronze, one^fiftieth 
 inch in thickness and one-fourth inch in width. It is nickeled 
 throughout, excepting the relief in which the figures are etched, 
 which is plain. The tape, accurately subdivided to feet, with foot 
 marks numbered consecutively between such limits as may be neces- 
 sary, is furnished with each gage. A 1-foot scale divided into 100 
 parts, and having every fifth division mark suitably numbered, is 
 placed in the box so as to stand cornerwise back of the tape in a ver- 
 tical position. This scale is made of No. 16 gage iron, enameled in 
 black and white with six coats of enamel, and is attached to an iron 
 bar which projects upward tlirough the top of the box, the projecting 
 end being covered by a cast-iron cap or cover attached to the box 
 by screws, the object being to provide a suitable bench or reference 
 mark outside the box. 
 
 The 1-foot scale is adjustable vertically. A standard weight of the 
 pattern used hN the United States Weather Bureau and the United 
 
26 INSTRUCTIONS TO SPECIAL EIVEE AND RAINFALL OBSERVERS. 
 
 States Geological Survey is provided with each gage, together with 
 a clip and wire for attaching the same to the tape. 
 
 Miscellaneous. — Each gage contains a covered compartment for the 
 observer's record card, etc., instructions for erecting a gage in various 
 positions, for attaching the weight, checking the gage datum, and 
 operating the gage. 
 
 A rectangular wooden down spout, 16 inches in length, with screw 
 for attaching the same, is provided with each gage. 
 
 Each gage is also provided with a screw driver and a f-inch twist 
 drill for use in erecting the gage. 
 
 Operation. — Release brake and slowly unwind tape until weight 
 reaches water. Do not run tape all out without holding reel handle. 
 Brake will hold reel in position, and observer can stand to one side to 
 see that tip of weight just touches water. Eead number of whole feet 
 on bronze tape and tenths of a foot on enameled scale. The figure on 
 the tape standing opposite some part of the 1-foot scale gives the 
 whole feet ; the number of tenths and hundredths on the 1-foot scale 
 opposite the index of the number on the tape gives the decimal or 
 fractional portion of the gage reading. 
 
 For example, if the number 7 on the tape stands opposite 60 on the 
 enameled scale, the gage reading would be 7.6 feet. If the number 
 —2 feet (2 feet below zero) is opposite 74 on the enameled scale the 
 reading is —2.26, recorded —2.3 feet (2.3 feet below zero) — 1 foot 
 —0.74 foot=0.26 foot, for the fractional part — the complete read- 
 ing being —2.26. When the reading is beloAv zero the num- 
 ber on the enameled scale opposite the figure on the tape will be sub- 
 tracted from the number of whole feet recorded. 
 
 Erection. — The gage may be bolted to the handrail of a bridge, if 
 not liable to interference, one side being fastened to tiebars that 
 extend down to the floor of the bridge. It may also be secured to a 
 platform extending beyond the handrail, the bottom of the box being 
 on a level with the top of the rail. When there is no handrail, as on 
 most railroad bridges, the gage may be bolted or secured to vertical 
 bridge members, or it may stand on horizontal bridge chords, or be 
 attached to two sleepers at their ends. In all cases room must be 
 provided for the unobstructed movement of the weight. 
 
 A small supply of Mott gages, ready for installation, remains on 
 hand at the central office and bids for installation will be necessary. 
 These gages will be supplied where suitable for the local needs, but as 
 a rule preference will be given to the chain and weight gage described 
 on previous pages. 
 
 In each instance the exact distance from the zero stage of the water 
 to the bottom of the gage box when in position must be furnished. 
 
IlfSTIlUCTIONS TO SPECIAL EIVER AND RAINFALL OBSEEVEES. 27 
 TABLE FOR CONVERTING INCHES INTO TENTHS OP A FOOT. 
 
 If the river gage is graduated in feet and inches, the inches will be 
 converted into tenths of a foot by the following table before tele- 
 graphing : 
 
 1 inch of water equals one- tenth (0.1) of a foot. 
 
 2 inches of water equal two-tenths (0.2) of a foot. 
 
 3 inches of water equal two-tenths (0.2) of a foot. 
 
 4 inches of water equal three-tenths (0.3) of a foot. 
 
 5 inches of water equal four-tenths (0.4) of a foot. 
 
 6 inches of water equal five-tenths (0.5) of a foot. 
 
 7 inches of water equal six-tenths (0.6) of a foot. 
 
 8 inches of water equal seven-tenths (0.7) of a foot. 
 
 9 inches of water equal eight-tenths (0.8) of a foot. 
 
 10 inches of water equal eight-tenths (0.8) of a foot. 
 
 11 inches of water equal nine-tenths (0.9) of a foot. 
 
 o 
 
LIBRARY OF CONGRESS 
 
 019 953 642 4