Adaptive Management For Watershed - Phosphorus Reduction Assessment, Modeling, and Monitoring

      Eutrophication caused by excessive inputs of nutrients, i.e., phosphorus and nitrogen, is a growing water quality problem in rivers, lakes and estuaries. Runoff from both rural (fertilizer and manure) and urban (urbanizing landscapes and uncontrolled storm sewer outfalls) would increase source loadings. Watershed Adaptive Management (WAM), a regulatory approach, can put a premium on all parties working together to improve water quality.  WAM in a natural resource context can involve learning from the outcomes, either expected or unexpected of implementing actions. For example the WAM Option is a provision of Wisconsin’s phosphorus rule. As a result certain sewerage districts around the state can have an alternative path to reduce phosphorus levels in surface waters, required to do by the Clean Water Act – instead of removing phosphorus exclusively through technology at treatment plants. In other words, some attempt can be made to keep phosphorus out of the water in the first place. One challenging task is to  develop an effective water quality monitoring strategy that can document whether progress in reducing phosphorus is being made. To achieve this goal, we are currently developing a watershed model that can be used to address field scale changes for adaptive management in the Yahara watershed. Specifically we would employ unstructured/TIN grids to delineate detailed spatial information (digital elevation model, soil type and land use), in contrast to traditional watershed delineation methods.  Furthermore to effectively monitor success or issues of the WAM for regulating external nutrient loading sources, we integrate the new unstructured/TIN watershed model into the INFOS-Yahara Lakes cyber-infrastructure.  The integrated watershed and INFOS Yahara can provide us with critical information for agencies/stakeholders to decide how to make informed decisions on regulations and allocate strategies for cost sharing.

Bioavailable Phosphorus and Sediment Dynamics in Stream Pools/Wetlands in Lake Watersheds

     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 interdisciplinary 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. 
dorn  wetaldns  

    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.

 wetland   dye  

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

Status :   Active


Student Investigators:  Xi Chen (MS), John Reimer (PhD)

Graduated: Owen Zhu (MS), Gary Guo (MS), Justin Roger (MS), Evan Murdock (MS), Doo-Yong Choi (PhD)


  • Guo, G., Wu, C.H., and Reimer, J.R., A multiple-time-scale approach to SWAT in urbanizing watersheds:development and application, to be submitted.
  • Zhu, Y., Reimer, J.R., Wu, C.H., 2015. Field-Scale Phosphorus Loading Assessment: Development and Application of TIN-Based SWAT Model, Best Student Poster Award , AWRA, 2015.
  • 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.