Thus with lakes as well as streams, it is important that the 

 fisheries interests be given an active place in the planning of water 

 development projects. 



Natural lakes have not yet been affected greatly by having irri- 

 gation waters drawn from them. Now with the development of modern 

 economical pumping units and spray irrigation, a potential danger has 

 developed. Undoubtedly water will be pumped from Montana's lakes 

 in increasing amounts. Maximum fish food production depends upon 

 minimum fluctuations in lake levels and these lake levels will be 

 drawn down drastically by such pumping units. 



A certain amount of water could be taken from lakes without 

 completely decimating the fish populations. The amount which could 

 be taken would vary from lake to lake. 



It would, therefore, be desirable if the Fish and Game Commis- 

 sion were authorized by law to file water rights on lakes important 

 to the recreational fishing industry, these waters to be left in the 

 lakes for fish production. Surveys could be made to determine how 

 much water could be drawn from these lakes without affecting the 

 fish populations drastically, and the Commission could then file 

 rights on the waters below this level. 



Water Sheds 



The watersheds of Montana are inseparably connected with the 

 fisheries resource. The populations of fishes can be no better than 

 the aquatic habitat, and the aquatic habitat can be no better than 

 the watershed upon which it is dependent for its water supply. 



The ideal, of course, is no land use, for with virgin stands of 

 grass and timber, spring run-off will be spread over longer periods 

 of time and the largest proportion of water possible will filter into 

 the ground to come out through the entire year as springs to sustain 

 water flows. 



Of couise, civilization dictates that this ideal not be maintained. 

 The land must be used. The more wisely it is used, the better will 

 be conditions in the streams and lakes. Over-grazing, poor timber 

 management, and other adverse agricultural practices all allow rapid 

 spring run-off which in itself is damaging to fish populations and 

 which also causes untenably low water flows in the streams through 

 the balance of the year. Adverse watershed use in Montana is a 

 major cause of declining fishing success. 



This problem has a bright side. Water and soil are the very 

 roots of mankind's existence. Ranchers must keep their all-important 

 topsoil on their land. It's their life-blood. Then too, they must manage 

 their land to permit a considerable amount of rainwater to soak 

 into the soil, so the plants will have water in long periods between 

 rains. 



Over-grazing huits the range; it reduces carrying capacity so 

 that in the future less livestock can be raised per acre of land at 

 the very time more is needed. 



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