|Shields Jr, Fletcher|
Submitted to: Proceedings of the World Water and Environmental Resources Congress
Publication Type: Proceedings
Publication Acceptance Date: 5/15/2005
Publication Date: 8/1/2005
Citation: Chao, X., Jia, Y., Cooper, C.M., Shields Jr, F.D. 2005. Numerical modeling of phosphorus cycle in a shallow oxbow lake. Walton, R., editor. Proceedings of the 2005 World Water and Environmental Resources Congress: Impacts of global climate change. American Society of Civil Engineers Proceedings 173(430), doi: 10.1061/40792(173)430, Reston, VA, CD-ROM. Interpretive Summary: Sediment has been identified as a leading nonpoint-source pollutant. One reason is that nutrients that cause potentially harmful algal blooms attach to clay sediment. Exchange of materials between water and sediment is an important component of the eutrophication process. Nutrients actively interact with suspended sediments and similarly, nutrients associated with bed sediment layers may be released or bound. In recent decades, some numerical models have been developed to simulate the phosphorus concentrations in lakes, rivers and coastal waters. However, few of them have simulated the processes of adsorption-desorption and bed release. In this study, a numerical model was developed to simulate the concentration distribution of phosphorus in Deep Hollow Lake. The phosphorus and related water quality processes were simulated. This phosphorus model was first tested using results obtained from laboratory experiments, and then it was applied to simulate the concentration of phosphorus in Deep Hollow Lake. A greater understanding of phosphorus will help meet the challenge of eutrophication in natural lakes.
Technical Abstract: A three-dimensional model was developed for simulating the phosphorus concentration in a shallow oxbow lake. The processes of mineralization, settling, adsorption, desorption, bed release (diffusion), growth and death of phytoplankton, etc, were considered, and the concentration of organic phosphorus, orthophosphate and phytoplankton were simulated. The adsorption and desorption of phosphorus from suspended sediment particles, as well as its release from bed sediment were verified using results obtained from laboratory experiments. The model was calibrated and applied to Deep Hollow Lake in the Mississippi alluvial plain. Simulated trends and magnitudes are generally in good agreement with field observations. Simulation indicates strong interactions between sediment-related processes and phosphorus concentration.