Rainfall Simulator Construction and Evaluation of Erosion Control Practices

Abstract

This thesis addresses the performance of erosion control products using the Auburn University Stormwater Research Facility ASTM D6459 rainfall simulators. Five products were tested for the ALDOT project Evaluation of ALDOT Erosion Control Practices using Rainfall Simulation. The Cover factors (C-factors) for jute, jute with polyacrylamide (PAM), jute with gypsum, ProMatrixTM hydro mulch, and EarthGuardTM EDGETM pellets were found to be 0.35, 0.45, 0.12, 0.42, and 0.45, respectively. Data from previous testing was compared. No product types differed significantly at the 2 in./hr (5.1 cm/hr). Hydro mulches performed mostly similarly with some failing to meet their minimum C-factor criteria. PAM was highly effective at the 2 in./hr (5.1 cm/hr) but failed similarly to the hydro mulches at higher intensities. Gypsum performed similarly to erosion control blankets. Additionally, PAM testing for residual runoff concentration using a spectroscopic method with centrifuging found high concentrations (>100 mg/L in some samples). Finally, in partial fulfillment of the ALDOT project Evaluation of ALDOT Erosion Control Practices using Rainfall Simulation on Various Soil Types and Slope Gradients, six new rainfall simulators were constructed, including literature review, soil testing and selection, design and modeling, grading, and assembly.