Mitigating Soil Erosion Caused by Artificial Disturbances in Hilly Lake Environs: Scenario Approach to LID Planning

Abstract

Low-impact development (LID) is crucial to mitigate soil erosion during artificial disturbance in hilly lake environs. However, little research on LID practices focuses on their scenario functions on long-term soil erosion events in macroscopic hilly watersheds, preventing the effective establishment of conservation strategies. Taking the Nanyi Lake region as an example, this paper models the scenario effectiveness of LID under existing framework and evaluates multiple-aspect effectiveness of planning on mitigating soil erosion in hilly lake environs. Based on the Revised Universal Soil Loss Equation (RUSLE), primary simulations were conducted on current conditions and the general land-use planning for 2020 to obtain soil loss and net soil loss, respectively. Low-impact development was deployed according to deficiencies of the previous planning and general principles. The function of certain LID methods was modeled via the P-factor in RUSLE concerning its area ratio and the correlation between its performance data and principal components to soil mass. Six indexes were employed to quantify the effect of planning on mitigating current soil erosion issues: the change ratio of annual soil loss, the change ratio of annual net soil loss to water, area ratio of a region with lower soil loss, area ratio of a region with lower net soil loss, Moran’s I of a region with lower soil loss, and Moran’s I of a region with lower net soil loss. Under functionally equivalent framework, these indexes were evaluated as −8.93%, −11.50%, 24.00%, 23.19%, 0.3315, and 0.1856 for the previous planning, and as −19.32%, −41.53%, 48.96%, 40.45%, 0.1045, and 0.0461 for the LID planning. Conclusively, LID deployment would not only reinforce the declining ratio of total soil erosion and sediment yield, but also cause broader and more dispersed patterns under lower impact compared with the previous planning.