小流域淤地坝建设的水土保持效益浅析

通过黄土高原地区坝系示范工程水土保持观测,分析了小流域淤地坝及坡面水土保持措施的动态变化、拦沙蓄水效益和淤地坝的增产效益。结果表明:由于降雨时空分布不均和沟道条件差异,5a间淤地坝拦沙量差异显著,呈现出先大幅度减小,后小幅度增加的趋势;与梯田和坡耕地比较,淤地坝的平均增产效益分别达到36.4%(梯田)和78.9%(坡耕地)。提出了坝系观测中应注意的几个问题,对促进完善小流域淤地坝建设和效益评价具有重要意义。

Analysis on Benefits of Soil and Water Conservation from Check Dam in Small Watershed

Through soil and water conservation monitoring on effects of check dams demonstration project,the dynamic changes of check dam and soil and water conservation measures on slope were analyzed.Water storage and silt detention effects and crop output effect associated with check dams were identified as well.The results showed that the amount of silt detention varied from year to year,firstly decreasing dramatically then increasing slightly because of the different precipitation characteristic and channels;the crop output on check dams was 36.4% higher than that on terrace,78.9% higher than that on sloping land.In the end,a couple of principles about soil water conservation monitoring on dam system were outlined,which was meaningful to perfect construction and assessment of check dams in small watershed.