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e -"0 .., 'j .' U~ '""", ~. The conclusions reached on this area were: "Forests do not conserve the water supply because alter their re- moval there was an increase in average annual yield amounting to 15%. II Mr. Ed. Munns, in charge of experimental work for the Forest Service, estimates that man's activities in the National Forests to date have in- creased the runoff from those areas 5 percent. ESTIMATED INCREASED RUNOFFS IN THE FOREST AREAS OF THE UPPER BASIN DUE TO MAN'S ACTIVITY The Forest Service maps show there is an area of approximately 2Z,190 square miles in National Forests and ParIes in the Upper Basin, which is divided between the states as follows: State Square Miles Colorado New Mexico Wyoming Utah Arizona 14,376 90 2,104 5, 595 25 Total 22,190 The area and mean elevation were determined for all the National Forests in the Basin and in order to determine the runoff from these areas,the mean elevation and the average runoff per square mile for a large number of stations for years 1914 to 1947 were plotted. Three curves :were drawn on this exhibit--one representing the lUnoff per squaJ:'e !mile for areas in Utah, . Wyoming and Northern Colorado, one representing the runoff per square mile in CentJ:'al Colorado areas, and one' representing the runoff per square mUe for areas in Southern Colorado. The runoff per square mUe for each of the forest areas was determined from these curves and total runoff of forest and range lands was adjusted to fit the recorded runoff from the states. The increase in runoff caused by man from the National Forest areas for the States of the Upper Basin has been estimated and is shown as follows: Colorado NatiOnal Forest Area- 14,376 sq. mi. Average Elevation - 9,679 feE!t above sea level Total runoff from National Forest area - 8, 250, 000 acrE! feet -6-