C. Joel Sprague of Greenville, S.C., won the 2008 Most Distinguished Technical Paper Award from the International Erosion Control Association (IECA) earlier this year. His paper, “Slope Erosion Testing: Identifying ‘Critical’ Parameters,” describes how different lab testing procedures used by three laboratories to evaluate the likely performance of erosion control products in the field produced different results.
Sprague, a senior engineer with TRI/ Environmental, received the award during ceremonies at the annual IECA conference in Orlando in February. The award is given to one paper presented at the annual conference that contributes most significantly to advancing erosion control knowledge. It recognizes clear, concise technical writing that presents innovative solutions to erosion control problems.
The labs that Sprague studied measured the amount of soil loss on treated and unprotected slopes caused by rainfall generated by rainfall simulators using procedures designed to closely simulate actual field conditions. Two of the labs used a standard industry protocol to evaluate erosion control product performance in outdoor test plots on actual slopes. The other lab tested product performance indoors on a tilting bed using a different protocol.
A number of factors, including rainfall energy and intensity, soil erodibility, and slope geometry can affect the amount of erosion. “Each of the various factors can vary significantly between the indoor and outdoor testing protocols examined,” Sprague said. “This suggests that very different simulated conditions may exist between outdoor plots on actual slopes and indoor plots on tilting beds.”
Sprague compared actual soil loss on the various test plots with the loss predicted by the Revised Universal Soil Loss Equation (RUSLE). He found a “reasonable consistency” between the standard industry test protocol for the two outdoor tests and performance in the field predicted by the RUSLE. “It was not clear if other protocols, such as those used [indoors], correlated in a similar manner,” Sprague said.
“Actual test results from other labs/ protocols should be similarly compared to RUSLE to assess whether measured laboratory performance in those protocols satisfactorily correlates to expected field performance,” he concluded.