Evaluation of hydromulches as an erosion control measure using laboratory-scale experiments

Discharge of sediment-laden stormwater from active construction sites, such as highway construction projects, continues to be a growing concern in the construction industry. Therefore, there has been an increased interest in research efforts to test many different erosion and sediment control practices. The purpose of this research effort was to test the laboratory-scale performance of four hydromulches and two methods of mulching (crimped and tackified), normalized to a bare soil control condition using 0.6 m (2 ft) wide by 1.2 m (4 ft) long test plots. The treatments consisted of a (1) bare soil control, (2) conventional straw, crimped, (3) conventional straw, tackified, (4) wood fiber hydromulch, (5) straw and cotton hydromulch, (6) cotton fiber reinforced matrix hydromulch, and (7) bonded wheat fiber matrix hydromulch. Each treatment was subject to simulated rainfall, divided into four 15 min rainfall events with 15 min breaks in between, producing a total cumulative rainfall of 11.2 cm (4.4 in.). To determine the overall performance of each treatment, turbidity and soil loss measurements were continuously collected from plot runoff. The products tested provided a reduction in turbidity of 80%, 98%, 85%, 92%, 95%, and 99%; and a soil loss reduction of 96%, 98%, 94%, 97%, 99%, and 100%, respectively. Overall, the results showed that the four tested hydromulch practices and conventional straw applications were successful in controlling and reducing erosion under laboratory-scale simulated rainfall conditions.