Publication Type:
ThesisSource:
Soil Physics and Land Management, Wageningen University, Volume Master of Science in International Land and Water Management, Wageningen, The Netherlands, p.42 (2016)Abstract:
<p>Although restoration of native vegetation in agricultural watersheds would decrease soil loss, this approach is not feasible in communities that base their income on agriculture. However, an alternative exists: strategically placing a small percentage of vegetative filter strips (VFS) within agriculture fields for erosion control. Factors influencing their effectiveness are runoff conditions, vegetation type, filter strip width, slope, soil type, and rainfall characteristics. With the perspective of increasingly stronger rainstorms and hence higher runoff, there is a need to obtain new insights about VFS design and its influence on sediment dynamics. The objective of the study was to analyze strip width impact on soil and water movement. Different strip widths were analyzed under a range of rainfall intensities using the event-based, hydrological and soil erosion model LISEM. The results show that sediment trapping efficiency (STE) increased directly with width, however decrease with rainfall intensity. On average, STE increased by 8% as the width of the filter increased from 4 to 14 m. Detachment and soil loss mainly occurred in rills caused by concentrated flow. Overall the first meters of the VFS experienced the most sedimentation but in places where rills crossed the buffer, stream power and turbulence resulted in sedimentation along the VFS.</p>
