| Nitrogen, phosphorus, and sediment transport is a concern for Northwest Arkansas due to high exports through riverine discharge. Urban, agricultural, and pastured watersheds have been associated with increased N, P, and sediment concentrations when compared to forested catchments. The objective of this study was to evaluate discharge and nutrient loads associated with a small urban, agricultural (row crop), wetland influenced, and pasture/farmland sub-catchment within four ephemeral drainages and located at the Watershed Research and Education Center in Fayetteville, AR. Samples were collected during base flow conditions and periodic storm flow conditions from 2009-2012. Flow adjusted concentration trends were used to develop seasonal and annual constituent loads for each catchment. A strong correlation between discharge and N, P, and sediment (r>0.896, p<0.001) occurred throughout all ephemeral drainages. The largest yields for N, P, and sediment were associated with the pastured/farmland sub-catchment, while high yields were generated from the agricultural sub-catchment. The lowest N and P yields were generated from the urban sub-catchment, and the lowest sediment yield generated from the wetland influenced sub-catchment. Results of this study reveal the relationship between small watershed scale (<140 ha) landuse and its effect on N, P, and sediment transport and storage. |
