ARS | Publication request: NEW FURROW FLUME FOR HIGH SEDIMENT LOADS

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 11, 2004
Publication Date: March 15, 2005
Citation: Clemmens, A.J., Bjorneberg, D.L. 2005. New furrow flume for high sediment loads. Applied Engineering in Agriculture, 21(2)227-236.

Interpretive Summary: Agricultural return flows to streams and rivers from irrigated fields often carry excess nutrients. These nutrients are essential for crop growth, but can cause eutrophication in streams and rivers. Phosphorus is particularly a problem in the Pacific Northwest. It has been shown that much of the phosphorus entering streams from furrow irrigation runoff is associated with sediments carried by the water. Thus, methods to reduce soil erosion are needed to reduce the amount of phosphorus leaving an irrigated field. Methods for measuring water flow and soil erosion are essential for making recommendations on farm irrigation practices to reduce both water losses and soil erosion. In this paper, we develop a new furrow water measurement device that provides good water flow measurement and better sediment flow measurement for making recommendations on improved irrigation management. This new flume, Powlus-T, is now commercially available. These results should be of use to consultants, farm advisors, researchers, Natural Resources Conservation Districts, and the Natural Resources Conservation Service. Ultimately better management of irrigation water supplies will conserve water and benefit the environment.

Technical Abstract: Measurement of water flow in furrows from either irrigation or rainfall is difficult when significant soil erosion occurs. It can be accomplished by backing up flow in the furrow, which for moderate to steeply sloping fields causes only small changes in furrow water depth and thus, has little influence on the water flow measurement. However, the ponding of water behind a flume can have a significant impact on the movement of sediment down the furrow. In one research study, measured soil erosion through the flume was reduced 40% over that measured in a furrow with only a non-constricting metal form that matched the furrow shape. A new furrow flume has been designed that overcomes the limitations of current v-shaped flumes or trapezoidal RBC flumes that cause significant backwater during furrow irrigation. This new flume has a trapezoidal shape, but with only a side contraction. It was designed to keep flow velocities high over the full range of flow conditions. This new flume has been constructed, is commercially available, and has been working successfully in the field for two seasons.