DEVELOPMENT OF A RAINWATER HARVESTING SYSTEM FOR INCREASING SOIL-MOISTURE IN ARID RANGELANDS OF PAKISTAN

Soil moisture can be significantly increased with microcatchments that have 4 to 5 m long water catchment aprons and 7 to 15% slope gradient s. The increase was by 59% (from 10.9 to 17.3% vol/vol) from the surfa ce to 15 cm depth, by 63% (from 11.5 to 18.8% vol/vol) from 15 to 30 c m depth, and by 80% (from 11.3 to 20.3% vol/vol) from 30 to 45 cm dept h. Increases in soil moisture were found in both the late summer and t he late winter season when the highest precipitation is received. Ther e are some year-to-year differences depending on how much precipitatio n is received each year. Rill erosion on the aprons increased with apr on length and gradient. Erosion volumes were quite low (14.9 l to 26.3 l) considering the amount of area of an apron (120 and 150 m(2)). (C) 1995 Academic Press Limited