黄河河龙区间黄土丘陵沟壑区土壤侵蚀模数与小流域泥沙来源研究

黄河流域河龙区间面积１１．１６万ｋｍ２，６０年代年均输沙量９．５２５亿ｔ，年均输沙模数８５３５ｔ／ｋｍ２。考虑水库等栏沙，还原计算的年均产沙量为９．８２４亿ｔ，扣除轻微流失面积３．８２万ｋｍ２及其年产沙量０．２９７亿ｔ，黄土丘陵沟壑区７．３４万ｋｍ２面积上年均产沙量９、５２７亿ｔ，年土壤侵蚀摸数为１２９８０ｔ／ｋｍ２，比年均输沙模数高出５２．１％。在小流域泥沙来源分析中，将坡长２０ｍ径流小区的年产沙模数改正为自然坡长的年产沙模数，加上坡面浅沟汇流加大冲刷的作用，未治理坡耕地年产沙模数在１５０００ｔ／ｋｍ２以上。由此算得的小流域各地类年产沙模数，作为工程规划设计和计算水土保持减沙作用的依据较为接近实际。

Study on Soil Erosion Modulus in Gullied and Rolling Loess Region and on Sediment Source in Small Watersheds in the Reaches from Hekouzhen to Longmen of the Yellow River

The annual average sediment transportation amount was 952. 5 million t and annual averagesediment transportation modulus was 8535 t/km2 in the 1960s in the reaches from Hekouzhen toLongmen of the Yellow River,with an area of 111. 6 thousand km2. Considering the amount retained by reserviors,the actual annual average sediment yield should be 982.4 million t. After deducting slight soil loss area 38.2 million km2 and its annual sediment yield 29. 7 million t,the annual average sediment yield in area of 73.4 thousand km2 of gullied and rolling loess region was952. 7 million t and the erosion modulus was 12980 t/km',which was 52.1% more than the annual average sediment transportation modulus.In the analysis of the sediment source in small watershed,the annual soil erosion modulus in runoff plot with slope length 20-meter was changed tothe modulus with natural slope length,and the effect of confluence's washing in shallow on slopesurface was considered,the annual soil erosion modulus of slope farmland which had not beenharnessed was above 15000 t/km2.The annual soil erosion moduli of different land forms calculated from this datum were relatively closed to the actual conditions, and could be used as base for engineering design and calculating the benefit of sediment reduction by soil conservation work.