TY - JOUR
T1 - Comparison of subsurface and surface runoff phosphorus transport rates in alluvial floodplains
AU - Mittelstet, Aaron R.
AU - Heeren, Derek M.
AU - Fox, Garey A.
AU - Storm, Daniel E.
AU - White, Michael J.
AU - Miller, Ronald B.
N1 - Funding Information:
This material is based upon work supported by the U.S. Environmental Protection Agency Region VI, Oklahoma Conservation Commission, Oklahoma Agricultural Experiment Station, and Oklahoma State University College of Agricultural Sciences and Natural Resources. The authors acknowledge Mr. Dan Butler and Mr. Bill Berry for providing access to the alluvial floodplain property. Amanda K. Fox, Stillwater, OK, is acknowledged for her assistance with the MATLAB software. We acknowledge Dr. Chad Penn, Oklahoma State University, for assistance with analysis of phosphorus data, and Dr. Todd Halihan, Oklahoma State University, for assistance with the electrical resistivity surveying. The authors also acknowledge Grant Graves, Katie Beitz, Jorge Guzman, and Jesi Lay, Biosystems and Agricultural Engineering, and Elliot Rounds, Plant and Soil Sciences, Oklahoma State University, for assisting with field and laboratory work.
PY - 2011/5
Y1 - 2011/5
N2 - Phosphorus (P) loading to streams can occur by both surface runoff and subsurface transport, with subsurface P transport often assumed negligible. Groundwater P concentrations in alluvial aquifers can be significant, especially in preferential flow paths (PFPs). The objectives of this research were to quantify subsurface P transport rates at two sites in northeastern Oklahoma and to compare them with surface runoff P transport rates derived from a hydrologic model, the Pasture Phosphorus Management Calculator (PPM Plus). Ozark ecoregion study sites were adjacent to the Barren Fork Creek and Honey Creek in northeastern OK, USA. Each site, instrumented with 24 observation wells, was monitored for several months for both groundwater levels and P concentrations. Using the flow and P concentration data, Monte Carlo simulations with Darcy's Law and a P transport rate equation were used to calculate the distributions of subsurface P transport rates across a transect within the well field containing a single identified PFP. Total subsurface P transport rates, through both the non-PFP flow domain and a single PFP, were estimated to be 0.04kgyear-1 and 0.03kgyear-1 for the Barren Fork Creek and Honey Creek field sites, respectively. Monte Carlo simulations for surface runoff P transport rates with PPM Plus resulted in average total P surface runoff transport rates of 0.07kgyear-1 for the Barren Fork Creek site and 0.08kgyear-1 for the Honey Creek site. For the groundwater at these floodplains, the P source was P-laden stream water flowing into the alluvial aquifer and a minimal quantity of P leaching from the surface. Results indicated that the subsurface P transport rates for small (3ha) alluvial floodplain sites in the Ozark ecoregion were at least 0.03-0.04kgyear-1, although subsurface P transport rates may be higher in cases with greater numbers of PFPs and where the subsurface is connected to a larger P source.
AB - Phosphorus (P) loading to streams can occur by both surface runoff and subsurface transport, with subsurface P transport often assumed negligible. Groundwater P concentrations in alluvial aquifers can be significant, especially in preferential flow paths (PFPs). The objectives of this research were to quantify subsurface P transport rates at two sites in northeastern Oklahoma and to compare them with surface runoff P transport rates derived from a hydrologic model, the Pasture Phosphorus Management Calculator (PPM Plus). Ozark ecoregion study sites were adjacent to the Barren Fork Creek and Honey Creek in northeastern OK, USA. Each site, instrumented with 24 observation wells, was monitored for several months for both groundwater levels and P concentrations. Using the flow and P concentration data, Monte Carlo simulations with Darcy's Law and a P transport rate equation were used to calculate the distributions of subsurface P transport rates across a transect within the well field containing a single identified PFP. Total subsurface P transport rates, through both the non-PFP flow domain and a single PFP, were estimated to be 0.04kgyear-1 and 0.03kgyear-1 for the Barren Fork Creek and Honey Creek field sites, respectively. Monte Carlo simulations for surface runoff P transport rates with PPM Plus resulted in average total P surface runoff transport rates of 0.07kgyear-1 for the Barren Fork Creek site and 0.08kgyear-1 for the Honey Creek site. For the groundwater at these floodplains, the P source was P-laden stream water flowing into the alluvial aquifer and a minimal quantity of P leaching from the surface. Results indicated that the subsurface P transport rates for small (3ha) alluvial floodplain sites in the Ozark ecoregion were at least 0.03-0.04kgyear-1, although subsurface P transport rates may be higher in cases with greater numbers of PFPs and where the subsurface is connected to a larger P source.
KW - Alluvial floodplains
KW - Hydrologic modeling
KW - Phosphorus management
KW - Preferential flow
KW - Subsurface transport
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U2 - 10.1016/j.agee.2011.04.006
DO - 10.1016/j.agee.2011.04.006
M3 - Article
AN - SCOPUS:79958056025
SN - 0167-8809
VL - 141
SP - 417
EP - 425
JO - Agriculture, Ecosystems and Environment
JF - Agriculture, Ecosystems and Environment
IS - 3-4
ER -