Feet. Pleasant Creek 28 Ephraim Creek 28 Manti Creek 28 Springtown Creek 14 Fairview Creek 10 Wales Creek 6 Fountain Green 10 Moroni 10 Creek between Ephraim and Manti 5 Creek between Manti and Gunnison 5 Creek above Fairview 2¹⁄₂ Twelve-mile Creek 28 San Pete at Gunnison 60 ------- Total 234¹⁄₂ This estimate is also liable to reduction, being undoubtedly a little in excess of the amount available at the critical period. This reduction may be as great as 15 per cent., which would leave very closely 200 cubic feet as the water supply of the San Pete Valley, which, added to the total of the Sevier above Gunnison, gives for the whole drainage system of the Sevier River a water supply of 860 feet per second at the time when the greatest amount is required. The next factor to be inquired into is the amount of land which a cubic foot per second of water can irrigate. This is, of course, highly variable, depending upon the nature of the soil, and the economy with which the water is applied, and the frequency of the irrigations. New lands freshly broken require much more water than the older ones which have been planted and watered for several years; and in fact the quantity diminishes with each season for a long term of years. In the San Pete Valley, which has been longest cultivated, the decrease in the amount of water applied to the oldest lands has not yet ceased, though some fields have been cultivated with regularity since 1857. The fresh soils are highly porous and absorptive, requiring a large quantity of water for their irrigation, and not retaining this moisture well under the great evaporative power of a dry and hot atmosphere. With successive irrigations, the pores of the soil are gradually closed and the earth is slowly compacted by the infiltration of impalpable silt brought by the irrigating waters. It absorbs water much more slowly, and retains it a much longer time. There is, however, a check to this increased irrigating power, arising from a wasteful mode of agriculture. It has not been the practice to employ fertilizers, nor any other conservative means of keeping up the fertility of the soil, and the yield of the crops growing smaller, the old lands are frequently abandoned, and fresh adjoining lands are broken, planted, and watered. It has been the practice to cut the straw, which is never returned as mulch; and, as there is but little rotation in crops, the result can be easily comprehended. So long as new land costs nothing but the labor to clear of the _Artemisia_ or sage brush, there is always the tendency to invade it as rapidly as the old lands show