the Wildlife Conservation Board, and a complete re- 

 port of these activities is shown under that heading. 

 Nine such dams were completed during the biennium, 

 three were started but not completed, and one previ- 

 ously constructed dam was raised to increase the water 

 storage. 



Other Flow Maintenance 



Irrigation waters were channelized into Pine Creek, 

 Lassen County, facilitating downstream migration of 

 trout into Eagle Lake. 



Gravel wing dams were constructed with bulldozers 

 on the lower Eel River, Humboldt County, to deepen 

 the channel and minimize losses of anadromous fish 

 attempting to enter the river. This was accomplished 

 with Federal Aid funds. 



Lake Construction and Improvement 



Work was begun on Indian Basin Lake, Fresno 

 County, where a trout lake of about nine acres in size 

 will be constructed with Wildlife Conservation Board 

 funds. This work is being done by a contract with the 

 U. S. Forest Service. 



Preliminary surveys have been made at several other 

 sites to determine feasibility of constructing other 

 trout and warmwater lakes. 



At Doane Lake in San Diego County, the marginal 

 area was deepened, an old dam removed, and vegeta- 

 tion controlled under a Wildlife Conservation Board 

 project. 



The bed of Dry Lake, San Bernardino County, was 

 treated with bentonite to eliminate water loss through 

 seepage. 



A diversion ditch was opened from Little Kern Lake 

 Creek, Tulare County, to provide a constant flow of 

 water into Little Kern Lake. A more permanent head- 

 works structure is planned for the next biennium. 



In accordance with instructions from the Legisla- 

 ture, the department made a survey of the snags and 

 logs in Lake Almanor, Plumas County, to determine 

 the feasibility of removing them. The survey indicated 

 that their removal would cost about $1,600,000. 



Stream Improvement Devices 



Spearheaded by a Wildlife Conservation Board proj- 

 ect, the department began a major stream improve- 

 ment program in southern California. Emphasis was 

 placed on pool building devices to provide sufficient 

 water and cover for planting of catchable trout. The 

 Santa Ana River received the greatest number of 

 structures with installation of 252 devices. 



Log and rock deflectors; log, piled rock, and rock 

 masonry dams have been installed on 13 different 

 streams. The type of structure used was determined by 

 the nature of the stream and the materials at hand, al- 

 though all are in experimental stages of design, location 

 and feasibility. 



Typical rock deflecfors constructed for flow maintenance and creation of 

 natural pools for trout fiabitat. 



Various counties assisted through county fine 

 monies. Many ^sportsmen and sportsmen's groups in 

 the area gave generously of their time and effort. As 

 a result of the combined efforts, more than 650 such 

 devices were installed. Unfortunately, flash floods pro- 

 duced by localized cloudbursts removed 92 in one 

 drainage. 



Aquatic Plant Control 



Continuing its policy of improving lakes for fishing 

 wherever possible, the department investigated uses 

 of new weedicides for control of aquatic plants. 



Pilot investigations of weed control were continued 

 at Twin Laks, Mammoth, Mono County, with sodium 

 arsenite, and the department did further work at 

 Doane Lake, San Diego County, and Crystal Lake, 

 Los Angeles County. Experimental work with CMU 

 was carried out at Lost Lake, Fresno County, and with 

 Borascu at the Moon Lake, San Bernardino County. 



Fish Population Control 



Chemical treatment continued to be the most useful 

 tool in control of undesirable fishes and reduction of 

 stunted populations. Rotenone-bearing powder was 

 the primary chemical used. Methods of application 

 varied from the use of a log raft in a back-country 

 lake to the dissemination of an emulsifiable rotenone 

 compound by aircraft. Aerial observation also proved 

 useful in the Grouse Ridge area lakes in Nevada 

 County so that accurate determination of lake areas 

 could be made. Such information is needed to deter- 

 mine the proper amount of chemical needed. 



California's own "cubebeater," a self-propelled mix- 

 ing device developed by the department was used 

 effectively on one of the big jobs at Lake Merced, 



