RESERVOIRS AND PONDS. 95 



ience take a volume of water of one million cubic feet. 

 If this amount is applied without loss in transporta- 

 tion, as through pipes, it will irrigate on an average 

 twenty acres of land for one season when used very 

 carefully. Assuming one-half of this area to allow for 

 unavoidable loss by absorption, evaporation, and the 

 loss by the ordinary pra(5lice of irrigation, the area 

 value of one million cubic feet of water will be consid- 

 ered as ten acres. On this basis of ten acres for one 

 million cubic feet, the cost of a reservoir built entirely 

 on the surface of nearly level ground from excavation 

 made within the area enclosed, without borrowing or 

 wasting material, has been calculated. The price 

 assumed for earthwork is twenty cents a cubic yard, 

 which for banks 20 feet high, with a long haul, is a 

 fair price. The size calculated is 1,283 ^^^t by 641.05 

 feet, holding 23,500,000 cubic feet of water. The cost is 

 $37,617, which at 7 percent, per annum interest would 

 be equal to an annual charge of $2,633, or $112.21 for 

 a million cubic feet, without any allowance for main- 

 tenance. This, at the area value of ten acres for a 

 million cubic feet, would irrigate 235 acres at a cost of 

 $11.22 an acre, which represents the total cost for all 

 time to come. 



At some sites it might be necessary to pump water, 

 and under the conditions likely to be met in pra(5lice, 

 where the work will be done in isolated localities and 

 confined to 90 or 120 days' work in the year, while the 

 interest on the cost of the plant will have to be charged 

 for a whole year, the cost will average about fifteen 

 cents a million cubic feet to the foot raised, or about 

 $15 to raise that amount of water 100 feet. This esti- 



