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Evaluation of percent flow captured by a small in-field runoff collector

Franklin, D.H., Cabrera, M.L., Steiner, J.L., Endale, D.M., Miller, W.P.
Transactions of the ASAE 2001 v.44 no.3 pp. 551
runoff, surface water, land management, water quality, water pollution, pollution load, nutrient management
Increased environmental concern about nutrient loadings in runoff and surface water has heightened the need for evaluation of management practices at the field scale. Thus, there is a need for small in-field runoff collectors to assess nutrient migration at the field scale on various land management systems. A runoff sampler previously designed for the relatively flat terrain of the Coastal Plain was modified to accommodate steeper slopes (5% to 12%), larger flow rates, and channelized flow common in the Southern Piedmont. We conducted a laboratory study with the modified sampler to evaluate the effect of flow rate (1 to 5.5 L min(-1)) and slope (5% and 12%) on percent flow capture. Our results show that slope and flow rate had little to no effect on the percent flow capture of the modified runoff collector. The 95% confidence interval for percent flow capture in a single observation was 10.4 +/- 2.5% for the 10x splitter and 2.0 +/- 1.7% for the 100x splitter. Because of the potential errors for single observations, several runoff collectors should be used if runoff volume needs to be quantified. The use of this small in-field runoff collector would be fairly unobtrusive, inexpensive in different management systems, and could help further our knowledge of migration of nutrients, pesticides, microorganisms, and sediments from fields into streams.