Assessment of Soil Erosion from an Ungauged Small Watershed and Its Effect on Lake Ulansuhai, China

Lake Ulansuhai, one of the main water sources for semi-arid areas China, has a local deposit caused by soil erosion during past decades. However, lack monitor stations prevents better estimation levels. Therefore, we try to estimate in Huangtuyaozi (HTYZ) watershed, an ungauged small watershed lake’s eastern using revised universal loss equation (RUSLE) model and multi-source remote sensing data, analyze its key drivers effect on lake siltation. The result showed that rate HTYZ ranged from 0 129.893 t ha−1 yr−1 with average 6.45 1986–2015. In particular, 80.06% area was less than 10 yr−1, just 0.06% over 50 mainly mountain area, southern part watershed. Moreover, rainfall erosivity factor is factor, flood season plays role erosion. Due HTYZ, siltation Ulansuhai reached 223.83 ha, annual increasing at 7.46 ha/yr. results could provide reference estimating areas.