Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-29
Total Federal Funds: $10,003 Total Non-Federal Funds: $21,557
Principal Investigators: Andrew Sharpley, Rosalind Dodd
Abstract: Phosphorus (P) is widely accepted as a key factor contributing to the eutrophication of many streams, rivers and lakes. The P content of streams is often related to the surrounding land use, for example in Northwest Arkansas the amount of dissolved reactive P in streams was shown to increase with increasing proportion of pasture and urban development within a watershed. Within NW Arkansas agriculture is the dominant land use, characterized by intensive broiler and beef cattle production. A recent symposium of the large amount of research and restoration work ongoing within the Illinois River highlighted “legacy phosphorus – identify and reduce” as the second most important research need in the watershed (Oklahoma Water Resource Center, 2014). This project aims to target the first of these challenges, identifying legacy P sources within a watershed in the Illinois River Watershed. Detailed analysis of the forms of P, both inorganic and organic, related to land use and landscape position will also help inform subsequent research aimed at reducing the impact of legacy P. The main aim of this study is to determine the sources and sinks of P along a flow path from the field/urban soil through a riparian zone to the streambed as affected by land use and riparian management. This research will be carried out in Goose Creek, a tributary of the Illinois River, a HUC 12 watershed with an area of roughly 114.5 km2. The watershed is mixed use and in 2006 land use comprised of 56 % pasture, 26 % forest and 12 % urban use. Pertinent features of the watershed include a wastewater treatment plant (WWTP ) at the upstream section of the main stem and three tributaries flowing into the main stem where bed sediments will be unimpacted by the WWTP. Riparian areas along the main stem of Goose Creek vary in their width, density and composition, providing an opportunity to study the effect of riparian management on legacy P. Also, some historic water sampling of Goose Creek by AWRC has occurred. In short, this watershed provides an ideal opportunity to address the following specific objectives: 1. To determine the forms of P within the soils and riparian, streambank and stream bed sediments within Goose Creek. 2. To determine which areas of the watershed are acting as a source or sink of P to Goose Creek. 3. To determine the impact of land use and riparian management on the P speciation and release potential within these zones.