Rainfall-runoff Characteristics of Artificial Micro-catchments for Rainwater Harvesting

LI Xiao yan, GONG Jia dong (Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000)

artificial catchments; rainfall runoff; rainwater harvesting

The results of the field experiments indicated that runoff from earth catchments (undisturbed loess slope, clearing loess slope and compacted catchments) occurred as infiltration excess process, and it was mainly depended upon rainfall intensity. Annual runoff mainly produced from a few high intensity rainfall events and the annual runoff efficiency ranged from 7.4% to 35.5%, therefore, more water would be collected from earth catchments by the increase of natural catchment area. The rainfall amount and intensity had little effect on the water yield from asphalt felt, asphalt spraying and concrete treated catchments with a mean annual runoff efficiency of 50%~80% and a high cost. The trend of high efficient use of harvested water for such catchments is to combine the water harvesting system with installation agriculture. The plastic catchment had low cost and higher annual runoff efficiency, but it could not resist radiation and lasted only 4~5 months. So temporarily moveable plastic film catchment can be recommended to use in rainy period in the field or yard for storing rainwater in the cistern for supplementary irrigation.