Agricultural inputs of phosphorus are major contributors of nonpoint source pollution to surface water bodies. Increased attention has recently been focused on the differentiation between total phosphorus and the portion that is actually “bioavailable”. Streambed/Pool sediments have been shown to be the main storage of phosphorus released from watersheds. It is believed that hydrodynamic processes play an important role in causing sediment resuspension, deposition, mixing, and advective and diffusive transport in the pools.  Other factors such as the grasses, and  plant material in the instream deposits and bank materials can also contribute to the erosion resistance of the channel material and are source of phosphorus. We are investigating the effects of hydrodynamic processes and physicochemical factors on the mobility of sediments in the Yahara River and its tributaries. Both field experiments and modeling in different type of pools (dry ditch, wet natural pool, and wet dredged pool) are conducted by our interdisplinary research team. Our final goal is to elucidate and quantify the in-stream processes governing the fate and transport of bioavailable phosphorus in channels and streams sediments. 
    

    Wetlands are unique features of the landscape that can significantly affect the movement and quality of surface and ground waters.  By temporarily storing water, wetlands can reduce flood peaks, sustain streamflow during dry periods, retain sediment and phosphorus, and promote denitrification. But throughout most of human history, wetlands have been considered "wastelands" and many have been drained for agriculture and other uses. For example, over 60 percent of the wetlands that once existed in the Midwestern U.S. have been lost, mostly to agricultural uses. Many of the remaining wetlands have been degraded, largely through ditching and channel incision. These degraded wetlands are predominantly located in agricultural areas where surface water quality is severely impaired by excessive sediment and nutrient loads. Despite their prevalence, little is known about the degree to which these degraded wetlands mitigate this impairment. This project is aimed to better understand the role of wetlands in controlling water quantity and quality through a nested modeling approach and field validation.

      

Sponsor : US-EPA/USDA
                City of Madison, WI
                Dane County Land and Water Resources Department
          

Status :   Active
Student Investigators: Owen Zhu (MS), Gary Guo (MS), ? (MS or PhD)

Graduated: Justin Roger (MS), Evan Murdock (MS), Doo-Yong Choi (PhD)

Publications: 

• Rogers, J. S. Potter, K.W., Hoffman, A.R., Hoopes, J.A, Wu, C.H., and Armstrong, D.E. Hydrologic and water quality functions of a small wetland, Journal of the American Water Resources Association, 45 (3), 628-640, 2009.
• Rogers, Justin M., Hydrologic and Water Quality Characteristics of a Small Wetland- Upper Dorn Creek Wetland, Wisconsin. Master Thesis, Dept. of Civil and Environmental Engineering, UW-Madison, 2006.
• Choi, D.Y., An non-hydrostatic model in open channel flows, Ph.D. Dissertation, Dept. of Civil and Environmental Engineering, UW-Madison, 2006.
• Evan Murdock, Transport and storage of sediments and solutes in a small agricultural stream, Dane County, Wisconsin, Master Thesis, Dept. of  Civil and Environmental Engineering, UW-Madison, 2005.