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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #322963

Title: Application of a Transient Storage Zone Model o Soil Pipeflow Tracer Injection Experiments

Author
item ZHOU, YAN - Oklahoma State University
item Wilson, Glenn
item FOX, GAREY - Oklahoma State University
item Rigby Jr, James
item Dabney, Seth

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/13/2014
Publication Date: 7/13/2014
Citation: Zhou, Y., Wilson, G.V., Fox, G.A., Rigby Jr, J.R., Dabney, S.M. 2014. Application of a transient storage zone model to soil pipeflow tracer injection experiments. In: ASABE -CSBE/ASABe Joint Meeting Proceedings, Montreal, Quebec Canada July 13-16, 2014. PP. 1-12.

Interpretive Summary: Soil pipes, defined here as large flow paths generally parallel to the slope, play an important role in many soil erosion problems. However, limited research has been performed on measuring and describing the characteristics of flow through soil pipes. The objectives of this research were to determine the appropriateness of using a streamflow model that includes storage of tracer along the flow path in determining flow characteristics of soil pipes. Tracer data were collected in four different soil pipes after a dye was injected in the upstream end of each soil pipe network which included three Branches (West, Middle, and East) of a Main Catchment and a Back Catchment in Goodwin Creek Experimental Watershed in Mississippi. Sampling stations were positioned along each soil pipe network. The storage zone model OTIS-P was used to estimate the following transport properties for each section, between sampling locations, of each soil pipe: the soil pipe cross-sectional area (A), storage zone cross-sectional area (As), and the exchange rate between the soil pipe and the soil storage zone ('s). The streamflow model was proven capable of predicting the observed dye transport for eight of the nine sections of the three Branches of the Main Catchment and five of the seven reaches of the Back Catchment soil pipe. Soil pipe transport properties fell within the range of values reported for flow and transport characteristics in streams. In general, application of OTIS-P to this unique subsurface flow condition suggested that soil pipes have larger As and 's compared to most stream systems. Such a model, if combined with sediment detachment model, may be used in future to predict the erosion of the inside of soil pipes which can lead to gullies forming and levee/dam failures.

Technical Abstract: Soil pipes, defined here as discrete preferential flow paths generally parallel to the slope, are important subsurface flow pathways that play a role in many soil erosion phenomena. However, limited research has been performed on quantifying and characterizing their flow and transport characteristics. The objectives of this research were to determine the applicability of a streamflow model with transient storage zone in deriving flow and transport characteristics of soil pipes. Tracer data were collected in four different soil pipes after a fluorescein dye was injected in the upstream end of each soil pipe network in three Branches (West, Middle, and East) of a Main Catchment and a Back Catchment in Goodwin Creek Experimental Watershed in Mississippi. Multiple sampling stations were positioned along each soil pipe network. The transient storage zone model OTIS-P was executed inversely to estimate transport parameters by soil pipe reach such as the soil pipe cross-sectional area (A), soil storage zone cross-sectional area (As), and exchange rate between the soil pipe and the soil storage zone ('s). Model convergence was achieved and simulated breakthrough curves of the reaches were in good agreement with actual tracer data for eight of the nine reaches of three Branches of the Main Catchment and five of the seven reaches of the Back Catchment soil pipe. Simulation parameters for the soil pipe networks actually fell within the range of values reported for flow and transport characteristics commonly utilized in streams. In general, application of OTIS-P to this unique soil pipe condition suggested larger As and 's compared to most stream systems. This was hypothesized to be due to relatively higher ratio of the wetted perimeter to flow area in the soil pipe.