Assessing impacts of riparian buffer zones on sediment and nutrient loadings into streams at watershed scale using an integrated REMM-SWAT model

Abstract

Riparian buffer zones in agriculture dominated watersheds play important roles in reducing nonpoint source pollution into aquatic ecosystems and are widely used as a Best Management Practice. Assessment of the effectiveness of riparian buffer zones by modeling method is widely used for watershed management as field measurement-based assessment is difficult and expensive.The integration of Riparian Ecosystem Management Model (REMM) and Soil and Water Assessment Tool (SWAT) has been developed to simulate the effect of nonpoint source pollution reduction by riparian buffer zones at subbasin scale. However, there are problems in using the integrated model at subbasin scale, as the size of subbasin partition could affect the pollutant reduction rate by riparian buffers. In this study, we partitioned a large watershed with size of 1331 ha into sub-watersheds with sizes of 666, 333, 166, 83, 51, and 29 ha, and then compared the different simulation results. We found that the modeling could yield more convergent results when the sub-watersheds were partitioned into suitable size. In the studied area, the suitable sub-watershed size was less than about 166 ha for runoff and nitrogen and 83 ha for sediment and phosphorus. Among the eight sub-watersheds (partitioned based on the size of 166 ha), results showed that the effects of riparian buffers on runoff and nutrient loading varied drastically. The reduction rate varied from 0.26% to 30.13% for runoff, 29.4% to 74.07% for sediment, 9.61% to 57.85% for nitrogen, and 18.61% to 68.12% for phosphorus, respectively.

Inhibiting Effects of Vegetation on the Characteristics of Runoff and Sediment Yield on Riparian Slope along the Lower Yellow River

“…Therefore, the restoration and maintenance of riparian ecosystem function has become a central and urgent need in geographical and ecological research [3]. At present, most researchers focus on the corridor [5], buffer [6] and revetment functions [7] of the riparian ecosystem, and carried 2 of 16 out studies on riparian structural features [8,9], biodiversity conservation and influencing factors [5], prevention and control of non-point source pollution [6] and riparian maintenance and soil erosion prevention [7,10,11]. However, compared to riparian biodiversity and agricultural non-point source pollution control mechanisms, soil erosion control of the riparian zone remains poorly understood.…”

Methodologies and Management Framework for Restoration of Wetland Hydrologic Connectivity: A Synthesis

“…Water diversion to control pollution was originally a lake purification technology, and there are many application examples with lake eutrophication. After the recovery, Black Brook in Canada had a sediment retention rate of 29.4% to approximately 74.07%, an N reduction rate of 9.61% to approximately 57.85%, and a P reduction rate of 18.61% to approximately 68.12% (Zhang C et al 2017). Yin et al (2018) calculated the environmental flows under different HC (high, medium, low) scenarios through consideration of water purification and ecological water demand and applied them to the Shili River, China.…”

Reduction of sediment yield by riparian vegetation recovery at distinct levels of soil erosion in a tropical watershed

“…Shan et al (2014) determined the optimal width of the vegetation strip that assured clean water in reservoirs that varied with the type of soil and topography. Zhang et al (2017) assessed the effect of the size of sub-basin partition on modeling and identified a reduction in sedimentation rate from 74.07% to 29.4%, due to riparian buffers, among the eight subwatersheds they studied. Moriasi, Steiner and Arnold, (2011) found that applying a riparian forest buffer only and a combination of a riparian forest buffer and filter strip buffer simultaneously resulted in a reduction in suspended sediment concentration by 68% and 72%, respectively.…”