Hydraulic Properties and Relationships for the Design of Subsurface Flow Wetlands

G.C. DeShon, A.L. Thompson, D.M. Sievers, A.T. Hjemfelt 1

Abstract

Ergun's equation was modified to account for the additional flow resistance of roots within a constructed rock-bed flume. Comparison of head loss for a range of flow rates through two sizes of rock media (creek rock diameter of 1.81 cm and pea gravel diameter of 0.62 cm) indicated that these modifications improved prediction of head loss compared to Ergun's equation with no modification. Flow through creek rock with roots was more sensitive to tortuosity and friction coefficients than was pea gravel. Differences in head loss between the two media would be expected to decrease with continued root growth.

  1. G.C. DeShon, Graduate Research Assistant; A.L. Thompson, Associate Professor; D.M. Sievers, Professor, Agricultural Engineering Department, University of Missouri, Columbia, MO 65211; A.T. Hjelmfelt, Research Hydraulic Engineer, CSWQRU, USDA-ARS, Columbia, MO. Contribution of the Missouri Agricultural Experiment Station. Supported by USDI Geological Survey, Missouri Water Resources Research Center, Grant 93107311.

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