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M co C\l o (_J o Power Tlwre are very attractive power possibili~ ti(~s connected with the project (See Rio Grande Joint Investigation Report). The pl'CSt.'nt plans however do not contemplate the development of power at t.his time ex- c('pt that the plans fat' the Wagon Wheel Gap Dam include the installation of pen- st ocks in the dam so that this additional use may be developed at any time. In the event powel' uses are added during constrllction, 01' thereafter, power of course would. be required to absol'b its proportion- ate shaJ'(~ of the cost of the project and the amount of the chal'ge to water lIsel'S be thC'l'cby proportionately l'cducpd. Report of the Reclamation Service For a complete report on th{~ project, re- ference is made to House Document No. 6.93, thcH.epol't submitted to Congress by the Secretary of the Interiol' I'f'latlve to the feasihility of ('onstructin~ reservoirs for ,joint irrig-ution a,nd flood eont.rol purposes on tlw San Luis Vnlley Pr'~),ject, on the Uio Grande Ilf'adwah~rs in Colorado. Outlet Drain Almost half of the San Luis Valley is nOn- tributary to the Rio Grande and all returns from this nrea al'(~ now lost by evaporation. :E~vapo-tl'anspiration stud ips show. that evapol'ation from thc valley floor aggregates appl'oximately two acre feet. pel' acre pel' year and the prccipitation avcl'nges nine inches. An aveJ'ag-c of OVer 400,000 aCI'(' feet pel" year is diverted into this area fram the Rio Gnlndc nimH', in addition to the waters of the mHny <:rceks and ~tl'eam.s flowing- into it [I'om the sUITounding mountain::,:; on the "V0St, North and East sides. Only a small portion of this watel' is actually eonsunwd by t.he crops gTown. The I'emaindel' accumulates in t.he marshes and ponds in t1w trough of the valley' and is lost by evapol'ation. The I'cmaindcl' of the valley \\'hich is tributary to Uw [{io Grande contribute'::> fl'om Wjf. to Hi';1r of thp totHI flow o[ t.he llio Gl'andt' past the Del Norte gilging station in l'C'turn flow for IIse in meeting schC'duled deliverie!-\ at the State linC' unde!' tlw Rio Grande Compact. It. was recognized by all t11l'ee states at the time the 1crnpOl'ary Compact was agreed upon in 1929, that if this vast territory nOw non-tributary to the river could be made tJ'ibutary, that most. of our interstate probM lems would be solved, and in that Compact all three states agreed to coopenlte in a program to nCCUI'C the con~truction of Uw Outlet Druin by the Fcdel'<l1 Government. -11- 'fhree surveys have been made of the Out- let Drain by the Reclamation Service, and two by the State of Colorado, durIng the last thirty years. Aerial surveys to show a II open water surfaces were made by the Sta te about ten years ago. The production of this drain has bcpn es- t.imated by the various engineers represent- ing the Government anq the States, at. amounts ranging from 40,000 acre feet pCI' year, by Watrous and Tipton, for the Stat.e, to as much as 160,000 acre feet by some of the earlier surveys. This variation was un- doubtedly caused by the fact that some sur- veys were made in wet years and some in dry years. A very careful check and survey is now being made by a joint committee of engi- neers representing the Reclamation Service, the Geological Survey and the State of Colo- rado, to determine with as much exactness as possible, the quality and quantity of water which may be expected from this source. A comparison of returns from that. por- tion of t.he valley which is tributary to the river would indicate that this Outlet should produce around 80,000 acre feet aDnually, but if it will produce as much as 23,000 acre feet one year with another, it will elimi- nate any possibility of any deliveries of water at the State line being required undel' the Compact. It is not anticipated that the San Luis Lakes will be drained. The Outlet Drain will pass west of these lakes and the name "Outlet Drain" is really a misnomer. On ac- count of the small difference in elevation from the trough to the river it will be impos- sible to construct a ditch deep enough t.o provide other than surface drainage, but the construction of this outlet will make the northern half of the San Luis Valley tribu- tary to the river, and allow return water now lost by evaporation to pass on down into the rivel' and augment the water supply of the Rio Gra.nde in Colorado. ,i, s Weminuche T ransmountain Diversion A study of the possibilities of securing additional water by transmountain diversion was first studied by the State Engineer of the State of Colorado, and latel' by the Reclamation Service in connection with the I:~io Gl'ande Joint Investigation. A t least 20,000 acre fect pCl' yea,}' can be added to the water supply of the San Luis Valley by the construction of this 1.l'an:.;- mountain diversion at a cost very much less than the same amount of water could be provided by additional reservoir construc- tion. Years will OCCUr in which no water will be available from this sourCe so that in 01'- der to make it fully effective, it can only b~