UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY WASHINGTON April 3, Mr. Wm. A. Lamb, 416 Power Block, Helena, Montana. Dear Mr. Lamb: There is transmitted herewith a copy of the joint report on the division of the waters of St. Mary and Milk Rivers for 1930, signed by Mr . Johnston and ~self. Following the receipt of Mr. Tuttle's telegram concerning the corrections in the record for Milk River at the eastern crossing it was found that this tabulation bad been omitted entirely from the reports received from Mr. Johnston. After telegraphic coliiillWlication, Mr . Johnston approved the revision of page 2 of Table 2 to include this tabulation. In the meantime Mr. Johnston's 'office had detected the inconsistency in the Milk River data and had suggested its elimina­ tion. HOwever, since this office bad adequate assurance of the correct­ ness of the record furnished, it toOk the liberty of including it despite Mr. Johnston's suggestion. Table 4 was not included in the copies of the report received from Mr. Johnston. Therefore, with Mr. Johnston's approval, copies of this table were made and included in the copies of the reports received from him. Mr. Metzger, the attorney of the State Department who has to do with these international matters, has indicated that be would like a copy of the report on the division of the waters of St. Mary and ¥ilk Rivera. If you have an additional oopy of the report please send it to Washington in order that Mr. Me~zger ~ be supplied. Very truly yours, ~ - ~ ( I Chief HYdraulic Engineer. Inclosure } Report to THE INTERNATIONAL JOINT COMMISSION on THE DIVISION AND USE MADE OF THE WATERS OF ST. MARY AND MILK RIVERS by J. T. JOHNSTON representing Canada and N.C. GROVER representing the United States 1930 REPORT TO THE INTERNATIONAL JOINT COMMISSION 1930. The Honourable , The International Joint Commission , Wa s hing ton , D. C., and Ottawa , Ontario . Gentlemen:- In compliance with the provisions of Cla u s e 10 of your order of the 4th of October , 1921, directing the division of the waters of St. Mary and Milk Rivers b etween the United S t a tes and Canada , we are transmitting herewith a report on the operations during the irrigation season of 1930. Respectfully submitted , Accred ited officer of His Majesty Accredited officer of the United States . April 7 th , 1931. Introuuc tiono The field work incidental to the divis ion and admini s tra tion of t he waters of t he St. Mary and Milk r ivers i n Alberta, Saskatchewan and Mon t ana was conducted , during the irr i ga tion season of 1930, by the same engineers as in previous yea'rs. / Dr. G. Ot is Smith, Director bf the United States Ge ological Survey, as accredited officer for the United States, wa s r epresented in the field by Mr. W. A. Lamb, District Eng ineer , Hel ena , :Montana. Mr. J. T. Johnston, Director, Dominion Wa ter Power and Hydrometric Bureau, as accredited officer of Hi s Majesty , was r epresent ed by Mr. s. G. Dawson, Ottawa, Canada. The water of the two rivers was divided between the two countries in accordance with the Order of the Commission dated in Ottawa, Canada, on 4th day of October, 1921. The hydrome tric data, on which this report is based, were obtained in Montana~ by engineers of the United States Geological Survey under the personal supervision of Mr. Lamb; while those from streams and ditches in Canada were collected by engineers of the Dominion Water Power and Hydrometric Bureau, under the supervision of the Commissioner of Irrigation, Calgary, Alberta. The joint international gauging stations were visited frequently by repres entatives of both countries. Wh en the natural flow of the St. Ma ry river fell below the combined capacity of the two canal s diverting there- from , and when the demand for water in each country was 2 . equivalent to or in excess of its share of the flow of St. Mary river, which was from early in July until tha ciosing of the canals, the f:i.eld engineers were compelled t o keep const antly informed as +o the natural flow of the ri 'T er , the water stared or released from storage and the quantity divcrt0d by -ea ch countr y . Any discrepancy in the division was, therefore, discover ed and ad j us tmen ts made to allow each country its proper shar e . Weekly statements showing the da ily division of the water were prepared and forwards d to the Superintendent, Le thbridge section , Canadian Pa ~ ifir'. Irric.., a tj_on S~Ist em and to the Proj oct Manager, Ur:.i t ed Stat es Bureau of Reclama tion , Malta , Montana. Watar from Swiftcurrent creek was s t ored in Sherburne Reservoir un til the end of June and l ater released to augment the United States share of St. Ma ry river and satisfy the increased demand for irrigation water from the lands in the Lower Milk RivGr valley in Montana. Division of Wat er. Owing to t he necessity of temporary repairs to the Spider Lake flume , the United States St. Mary canal was not _ope: ed until the 6th of June but was kept in continuous operation until September 13 ~1en it was closed for the season. An early clos ing of the canal was made to facilitate fu:{·ther permanent repairs to the flume . As the loss in the canal by seepage between the i ntake a~d the crossing of the St. Mary river, which was this year 18% of the water diverted at the headgates , is 3 .. ~ssu~e~ to return tireatly t o t he river chan ne l and eventually become av~i.l~ble to Canada, the discharge of 8 9,600 acre-feet passing in the Ca~1a J . at St , Ma ry ri~.rer is considered as the actual qua.Etity diverted from S t. Mary river by the United. Stat es. Of chis quanti.typ 85,900 acre-f'ef"t were delivered ·:::;o the Milk river and made ava2.lo.ole for j_r r igation in Mon tana~ This 4% loss in the canal b·::;tween St. MaY'y r:L ver crossing and Hudson B8.y Divide, a t t he end of the cana l, was largely due to exce s s ive evapora t ion. During the 1vinter months and f r om cho break-up early in ~p ri l until the firs t of July a porti on of the daily ~low o f Swif t current cre ek was stored in Sherburne Reservo ir. Ea :-c 1y tn J1.:;.ly it was fotmd that t J:1e share of the natu::.~al flow . of the St. lVJ}?.ry r J.ver- du6 to ti.10 Un ited S t a t e s ;vas insufficient GJ fulfi.l ~ne cle rn~lL-.::.s on t~1e .:;ar.al , c o1~ seque ~ tl y s tored water 1.va.s r e J. eased to J. ugn:.a nt this shar e . 1\ s only l2G acre- f eet were G..ive rt.ed from the Milk ri"ra r :Jas i :'.l. j_n Ca.nada during -~~ h i s s eason 1 · the n u t ural f~ o~ of the rjvor is consi dered a s being de livered to t he U:ni tecl_ S t ates. 'T'h e to ~;3. 1 diversion :'or irrigation from M~.l ,~_ r1ver· ln· Mon~ana ... wa s 183 , 416 a cre-:!:'eot. The total r ecorded f low crossing the Inte rnational Boundnry from the nort:C1ern tri buta::j_es o f Milk river d.uring the irrigation season of 1930 was 98 , 4.-00 acr 3-feet, uv-hich is abo1'. .t 20 1~ in excess of the flow r ecorded in l 929a .!J: 0 The Canadian Pacific Railway canal , previously known as ~h e Alberta Rail wa y and Irrigation Company canal , at Kimball , Alberta, diverted 158,000 acre-feet from the st. Mary river during the period of opera tion from April 17 to Oct ober 16, to irrigate lands in Southern Alberta . Ap pr ox ­ i mately 200 acre- feet were diverted from Re lph creek in the St. Mary river basin. 3,242 acre-feet were diverted from the northern tributaries of Milk river in Canada; 459 being from Lodge creek, 1,827 from Battle ~re e k and l,55f> from Frencl·man river. No wa~er was diver ted fr om t he other tributaries of Milk river. Any quest i on as t o the prop er share of st . Mary river being del i ve ~ ed t o e ither country was decided in the f ollow ing manner. Current meter measurements were made of Sw i f t curr ent creek at Many Glacier a nd Canyon creek near Many Glacier , hll_t the f l ow of the other small creeks entering Swiftcurrent above the Sherburne dam were estimated. The total flow of these creeks gave the inflow into Sherburne Reservoir. The evaporation and losses from the Reservoir were considered when estimating the flow from other small streams. A current meter measurement of the outflow from the r eservoir was made a.;_; the gaug ing stat ion belmv t hfl dam. The difference between the inflow and outfloYl shm1ed tne quantity of water being stored or released from storage. A 5.