A miner's inch is theoretically such a quantity of water as will flow through an aperture 1 inch square in a board 2 inches thick under a head of water of 6 inches in one second of time, and it is equal to 0.194 gallon, or o.c259337 cubic foot, per second, or to 11.64 gal., or 1.556024 cubic ft., per minute. The amount of water flowing through a given aperture in a given time varies, however, with the head of water over the opening, and also with the form of the opening. In Colorado the miner's inch legalized by statute equals 11.7 gal. per min. The California miner's inch, however, equals only 9 gal. per min., 100 Colorado inches being, accordingly, equal to 130 California inches. One hundred Colorado inches will cover an acre to a depth of 5.2 ft. in 24 hours; 100 California inches will cover the same area only to a depth of 4 ft. in the same time. Fifty California inches are, therefore, approximately equal to I secondfoot, and 50 Colorado inches equal to about three tenths more. An acre-foot of water is the amount required to cover an acre of ground to a depth of I foot. This is 43,560 cubic feet, or 325,851.45 gal. Its weight is 1213 tons 2113 pounds, at 2240 pounds to the ton. The amount of water required to cover an acre of ground to a depth of 1 inch is 3630 cubic feet, or 27,154.29 gal. Its weight is 101 tons 362 pounds, at 2240 pounds to the ton. A second-foot is the most satisfactory because the most definite unit of measurement for flowing water. It is used by the U. S. Government in the gauging of rivers and streams, and is rapidly superseding the miner's inch in the measurement of water for irrigation. It is the quantity represented by a stream I foot wide and 1 foot deep flowing at the average rate of 1 foot per second. In other words, it is 1 cub. ft. per second, 60 cub. ft. per min., 3600 cub. ft. per hour, etc. A stream flowing continuously at the average rate of 1 second-foot would carry in one day of 24 hours 86,400 cub. ft., or 646,316.9 gal., sufficient to cover 1 acres to a depth of 1 ft. Flowing continuously for one year of 365 days, such a stream would carry 31,536,000 cub. ft., or 235,905,678.7 gal., sufficient to cover 723111 acres to a depth of 1 ft. The sub-humid region is the strip of country running north and south between the arid region, where irrigation is absolutely necessary to the successful prosecution of agriculture, and those portions of the United States in which the rainfall is usually sufficient for agricultural purposes. It includes portions of North Dakota, South Dakota, Nebraska, Kansas, and Texas, and may be described as a region where irrigation is not always necessary, but where agricultural operations cannot, with any assurance of success, be undertaken without it. The average value of the irrigated land in farms in the United States was ascertained by the census of 1890 to be $83.28 per acre, and that of the non-irrigated land in farms $20.95 per acre. The average annual value of the agricultural products of the irrigated land was ascertained to be $14.89 per acre irri gated, and that of those of the non-irrigated land $6.80 for each acre improved. The average first cost of the irrigated land, including purchase money, water rights, etc., was ascertained to have been $8.15 per acre, and the average annual cost of the water supply $1.07 per acre. The total value of the irrigated farms of the United States, as reported by the farmers themselves, was, in round figures, $296,850,000, an increase of $219,360,000, or 283 per cent, upon their cost, including land, water right, fences, and preparation for cultivation. The total value of the productive irrigating systems was found to be $94,412,000, an increase of $64,801,000, or 219 per cent, upon their cost. POWER REQUIRED TO RAISE WATER FROM DEEP WELLS BY PUMPING. (APPLEBY.) Gallons of water raised per hour..... 200 350 500 650 800 1000 APPROXIMATE COST OF DIFFERENT KINDS OF PIPE USED FOR IRRIGATION. (WILCOX.) AVERAGE COST PER MILE OF CONSTRUCTING IRRIGATING CANALS AND DITCHES. CAPACITIES OF WINDMILLS AND PUMPS. (IRRIGATION AGE.) Sizes of Irrigation Mills and Pumps best Adapted for each other to Work Successfully under Ordinary Conditions. * Amount of land that can be covered 1 ft. deep with windmills working at the rate of 15 hours per day for 300 days in the year. Acres covered 1 ft. deep. + Capable of holding water for 24 hours' continuous pumping. These sizes should have 4 ft. depth of water, height of bank 5 ft., width of base 16 ft., 2 ft. of water below discharge-pipe not included. These reservoirs to connect with additional reservoir by overflow-pipe in order to utilize full capacity of mills and pumps. Overflow-reservoir should be of 1- and 2acre capacity, 8 ft. deep, banks 9 ft. high, base of bank 45 ft., acre size ft. on each side, corners rounded; 2-acre size 209 X 418 ft. 209 |