THE COMPARISON ON WATER RESOURCES EFFECT OF TYPICAL SOIL-SAVING DAMS IN THE LOESS PLATEAU

摘要

Through investigation on the spot, using the measured records and statistical analysis method, water resources effect of typical soil-saving dams in the Loess Plateau is researched. Soil water content of soil-saving dams in Jiuyuan is higher than Peijiamao; the latter is higher than Xindian. Soil water content in the branches is lower than in main ditches. Obvious wet or dry soil layers exist in certain depth. The change of it in the middle of dams is gentle. Above six meters, with the depth increasing, it shows an increase trend basically. It becomes stable in the middle and end part in certain depth. The total water storage of dams system in Xindian, Jiuyuan and Peijiamao basin is 5.14, 63.67 and 15.21 ten thousand m3 respectively; the benefits of water accumulation are 39.39, 20.94 and 8.85 percent respectively; the benefits of water decrease are 48.27, 44.06 and 38.16 percent respectively. The dams system of Xindian Ditch basin lead to surface water reduce by 9.87 ten thousand m3. All soil-saving dams of these three drainage areas can reduce surface water resources 88.75 ten thousand m3 at least; the contribution of runoff reduction to Wudinghe River is 0.093 percent. The effect is an important representation of man-made influence on water resources.