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. Much of what has been said is to stimUlate thought by the water user~owards the part he may play in conserving water. I believe that through education and demonstration, much can be accomplished tCi help individuals eliminate excess.iire wastes of water, and that probably twice as much land can be irrigate4 with the same water supply we now have if the water is used efficiently on well prepared land; . \0 . Another means of :water consi"rvationrequires cooperation ofindi- viduab as well as organiz.ed groups and state and federal, agencies.. That is the salvage of water used by vegi"tation on watersheds. In California 10 to 12 million acres of land are covered with brush so den.se that itis worthless, although it has potential val.ue for grazing. Loes of \.vater by evaporation from the soil surface is small when compared to losses by transpiration. :Every farmer who practices summer fallow applies this principle by letting land remain idle one year in order to store rainfall for use of crops the following year. Meantime, the land is cultivated to eliminate weeds. For many years it was thought the effectiveness of this practice was due to cultivation of the soil and maintenance of a dust mulch, but it has, been shown that the reason is, the carrying over of water from one year to the next by elimination of transpiration losses. Evaporation is confined to ashallow surface layer of soil. On .our drained hillsides, saturated soil conditions cannot be maintained long, so evaporation losses from these soils are small. However, mainten- ance of. a vegetative cover on watersheds. '.must be paid for by the expen- diture !;)f water. It then becomes a question of whether elimination of brush, usually plants which have no forage or commercial value, will save w~terand )V}:la.t effect its removal will have upon erosion. One would ~e rash to suggest that forests be denuded to save water because trees themselves are a valuable natural resource. Certainly considera- tion, however, should be given to the vast areas of brush. Perhaps it could be converted to ufileful plants, and at the same time save water. The soil on most watersheds is not deep and since the rains largely .come during the dormant seas.on, the growth of plants during summer depends upon water stored in the soil during the rainy season, Soils have limited water-holding capacities, which cannot be changed materially by addition of organic material or fertilizers in practicable amounts. Usually not more than 10 inches of water can be stored in hill soils and, in many cases, much less.. Brush takes all the water from the soil it can get. Complete elimination of vegetation would result in maximum saving of water, but accelerated erosion might result. In fact, it would be impossible to keep a large area clear of vegetation. Brush land. may be cleared by burning, but grasses soon grow in the clea.red areas.. As much as 3 inches of wate.r can be saved by substitution .of grass for brush. Most grasses do not have as deep root systems as brush plants. Annual grasses do not persist throughout the growing season and the perennials usually become dormant about mid-summer. Thus transpiration is reduced. Another means of water conservation is reduction in the amount of snow or rain intercepted 'by brush as compared to grass.. As much as 20% of the rainfall may be inter'cepted by brush. Not all of this is wasted, since some may flow dOwn the stems of plants to the ground,' but 10 to15% .of the rainfall may be lost through evaporation of the water .. .. . -17-