Cost Effectiveness of Erosion Control Covers during Vegetation Establishment under Simulated Rainfall

Abstract

The main goal of this study was to quantify reduction of runoff responses using selected erosion control covers on 1.2 m × 0.6 m plots under simulated rainfall to determine the most cost-effective temporary cover treatment under similar soils, rainfall and embankment slope conditions. The different erosion control covers tested were polyacrylamide (PAM), wheat straw and PAM (WS + P) with and without seed; and engineered fiber matrix (EFM) with and without seed. The EFM + S and WS + P + S treatments were the most effective treatments for runoff volume with 68.0% and 48.9% reduction, respectively, as compared to control. EFM + S was the most effective treatment for turbidity and modified total suspended solids (MTSS) with 98.7%, and 99.8% reduction, respectively as compared to control. Vegetation in the wheat straw treatment significantly reduced turbidity but less effect on runoff volume and MTSS than vegetation in the EFM + S treatment. Seeded treatments combined (EFM + S, WS + P + S) had a significant negative correlation between MTSS delivery and time (r = –0.69), as compared to a positive correlation of corresponding non-seeded treatments (EFM, WS + P) over time (r = 0.14). The EFM + S treatment had 39% less average MTSS delivery than WS + P + S but the WS + P + S treatment ($1.03 kg -1 sediment reduction) was found to be 84% less expensive than the EFM + S treatment ($6.36 kg -1 sediment reduction). The WS + P + S treatment can therefore be recommended as the most cost effective method for sediment delivery reduction under similar conditions and within the limitations of this small scale plot study.