SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Phosphorus flux from bottom sediments in Lake Eucha, Oklahoma 
Authors:Haggard, B.E., P.A. Moore, Jr. and P.B. Delaune 
Journal:Journal of Environmental Quality 
Volume (Issue):34(2) 
Article ID: 
URL (non-DOI journals): 
Broad Application Category:pollutant only 
Primary Application Category:phosphorus cycling/loss and transport 
Secondary Application Category:none 
Watershed Description:932 km^2 Lake Eucha drainage area, which drains portions of northwest Arkansas and northeast Oklahoma, U.S. 
Calibration Summary: 
Validation Summary: 
General Comments:Only one paragraph in "study stie description" section describes the SWAT application; 48 mg/yr (1998-2001) of total P loads were estimated with SWAT to be entering Lake Eucha. 
Abstract:Phosphorus inputs into reservoirs include external sources from the watershed and internal sources from the reservoir bottom sediments. This study quantified sediment P flux in Lake Eucha, northeastern Oklahoma, USA, and evaluated the effectiveness of chemical treatment to reduce sediment P flux. Six intact sediment–water columns were collected from three sites in Lake Eucha near the reservoir channel at depths of 10 to 15 m. Three intact sediment and water columns from each site were incubated for 21 d at approximately 22°C under aerobic conditions, and three were incubated under anaerobic conditions (N2 with 300 ppm CO2); sediment P flux was estimated over the 21 d for each core. The overlying water in the cores was bubbled with air for approximately 1 wk and then treated with aluminum sulfate (alum). The cores were incubated at approximately 22°C for an additional 14 d under aerobic or anaerobic conditions, and sediment P flux after alum treatment was estimated for each core. Sediment P flux was approximately four times greater under anaerobic conditions compared with aerobic conditions. Alum treatment of the intact sediment–water columns reduced (8x) sediment P flux under anaerobic conditions. Internal P flux (1.03 and 4.40 mg m–2 d–1 under aerobic and anaerobic conditions, respectively) was greater than external P flux (0.13 mg m–2 d–1). The internal P load (12 Mg yr–1) from reservoir bottom sediments was almost 25% of the external P load (approximately 48 Mg yr–1) estimated using a calibrated watershed model.