黄土高原不同类型区梯田蓄水拦沙指标的分析与确定

 为客观、科学地评价水土保持措施的蓄水拦沙效益,从确定梯田蓄水拦沙指标的约定和基本原则出发,结合不同类型区的实际情况,分析确定了黄土丘陵沟壑区第1、2副区和黄土高塬沟壑区梯田在不同降水条件下、不同质量等级的蓄水拦沙指标。结果表明:1)蓄水指标最大值出现在黄土高塬沟壑区,特别是较高质量(1、2级)梯田,在丰水年份,其蓄水效益最大,并且该类型区蓄水指标值随降水条件变化的幅度最大,丘1区的亚区2,是蓄水指标最小的地区;2)拦沙指标最大值,主要在丘1区的亚区1和丘2区,尤其是丰水年份及处于平水年的1、2级梯田,其值较其他类型区大多偏大20～70t/hm2;3)高塬沟壑区的拦沙指标值最小。

Analysis and confirm of the indexes of water storage and sediment trapping on the terrace of different type regions at the Loess Plateau

Terrace indexes of water storage and sediment trapping have been analyzed and confirmed according precipitation condition and terrace's quality in the loess hilly-gully region and loess gully region based on the promise and philosophy of the terrace index of water storage and sediment trapping, combing the physical circumstance of different typical region. The results showed that the index of water storage is larger in loess gully region than in other regions, and the storage benefit of high-class terrace in wet year, additionally, the variation amplitude of the water storage with variation precipitation in the region is higher, but the index of water storage in the second sub-region of the loess hilly-gully region is least. The maximum index of sediment trapping mostly appears in the first sub-region of the loess hilly-gully region and the second loess hilly-gully region, especially in all terrace in wet year or first and second terrace in normal year, which is 20～70t/hm² larger than other kinds. Index value of sediment trapping in loess hilly region is minimum among three regions.