WATER FOR FRUIT AND FARM LANDS. 7 



The Siskiyou portion of the Forest is drained by Ashland Creek 

 and Applegate Creek and its tributaries. The greater portion of 

 the Cascade division is drained by the Rogue River and its tribu- 

 taries, Evans Creek, Elk Creek, and Big and Little Butte Creeks. 

 (See map.) These rapidly falling streams cut the west slope of 

 the Cascades into canyons. The east slope has comparatively little 

 surface drainage ; . what streams there are flow into Klamath Lake 

 and Klamath River. Taking the Forest as a whole, four-fifths of 

 its entire drainage goes to the Rogue River Valley. 



WATER FOR FRUIT AND FARM LANDS. 



In general, the precipitation on the Forest is greater on the west 

 than on the east side of the Cascades. The amount, however, is 

 determined largely by the relief of the country. In the low-lying 

 valleys on the west slope, for instance, the climate is semiarid, while 

 on the east slope at high altitudes it is humid. The annual precipi- 

 tation on the higher mountains and on the Cascade Plateau probably 

 exceeds 70 inches. At the lower elevations on slopes and in valleys 

 the annual precipitation is seldom greater than 30 inches, and is 

 often 25 inches or less. During the three summer months there is 

 practically no rainfall. 



On the east slope much of the precipitation is in the form of snow, 

 since here it is much colder than on the west slope, and the only 

 rain that falls during the summer comes in short showers. Heavy 

 rain falls, however, in the spring and autumn. Snow falls to a 

 depth of from 6 to 10 feet at Lake o' the Woods and Four Mile Lake, 

 which are on the plateau, and in the vicinity of Island Lake, which 

 lies north of Four Mile Lake; and near the summit of the Cascades 

 the snow is from 10 to 14 feet deep throughout the winter. 



Over most of the Forest the rainy and dry seasons are marked. 

 The first extends from October to April or May, and occasionally to 

 the 1st of July. Probably 75 per cent of the yearly precipitation falls 

 between November 1 and May 1. In some years but few rains come 

 after April 1, and the effects of these are quickly counteracted by 

 long, dry, sunny periods. The snow leaves the mountains by April, 

 sometimes before. Such a climate makes protection from fire difficult 

 but imperative, if the water supply is to be conserved. The low, dry 

 foothills and valleys near the Forest are fertile, and wait only for 

 water to produce the best of farm crops. 



Four-fifths of the water which flows from the Forest is available 

 for irrigation of the Rogue River Valley, lying west of the Cascades 

 and north of the Siskiyous, one of the most productive apple and 

 pear centers in the United States. The climate of the valley is uni- 

 form, and favorable for all kinds of vegetables as well as for fruit. 

 The most central and largest market is Medford, which, with other 



