Investigated in 1916 by members of your Commission. The device consists of a 

 devolving wheel which fills the whole intake of a ditch and by mechanical means 

 is caused to revolve in such a way as to become self-changing. The last session 

 of the Legislative Assembly placed at the disposal of the Commission the sum of 

 $500 for the purchase of such wheels as an experiment, but when an effort was 

 later made to obtain the wheels from the makers, we were not able to obtain them. 

 The result is that no wheels have been installed, the appropriation has not been 

 used and destruction of trout in ditches continues, for owners of irrigation ditches 

 can not be pursuaded to protect the intake because of the trouble and expense 

 attendant upon the installation and cleaning of screens. In some streams, where 

 the water is all taken for irrigation we believe that the destruction of fish is 

 more than can be replaced by plantings, hence we have declined to restock unless 

 steps are taken to prevent this loss. 



Dams and Obstructions. 



The industrial growth of Montana, the development of its resources, has 

 resulted in the building of dams in many streams and rivers. The law now 

 requires a fish ladder or fish way to be installed at all such places, suitable for 

 allowing the migrating fish to go over the dam so that they follow their natural 

 impulse to spawn in the upper reaches of the river or small streams affluent 

 thereto. Many years observation of the results following the building of dams 

 fails to convince that such obstructions to streams are always detrimental. As 

 an example the dam in the Bighole river at Divide may be cited as an example. 

 The dam is a high one, a fish-way has always been maintained there, but no fish 

 have been observed to pass through it, altho at the foot of the dam each year, 

 in the spawning season, many spawning fish assemble, some are caught, many go 

 down river, evidently to spawn in side streams or in suitable places or lower 

 down the stream. We are reliably informed that the number of fish in the river 

 both above and below the dam is greater now than before the dam was built. 

 It is possible that the building of a dam which creates a large lake furnishes to 

 the fish a winter refuge which is availed of and that in this way a dam may 

 become a help, rather than a hinderance to fish life. Many fishermen who wit- 

 ness the frantic efforts of spawning fish to pass a dam or obstruction jump at 

 the conclusion that unless the struggling fish reaches the upper waters of the 

 river to spawn that its natural increase is lost. This need not be true, because if 

 the river itself has suitable spawning grounds, or if tributary streams have like 

 waters and suitable bottom conditions the fish will more than likely seek such 

 places for spawning. The fish which take advantage of the lake or pond created 

 by the dam for a winter refuge are likely to go to upper reaches of the river or 

 to side streams for a like purpose, so that nothing is lost, and perhaps some- 

 thing gained. 



It would be useless to require dams or fish ladders in streams where there are 

 no migrations of fish, so that the whole question may well be left to be dealt with 

 by the Commission as occasion may arise. 



(26) 



