Proposed Water Quality Criteria Necessary to Sustain Submersed Aquatic Vegetation in the Upper Mississippi River

October 1, 2003

We believe greater river and watershed management efforts need to be directed to protecting and enhancing submersed aquatic vegetation (SAV) on the Upper Mississippi River (UMR). In particular, efforts to reduce the negative effects of high turbidity or suspended particulate matter during the growing season are warranted to ensure the continued survival of SAV beds within historic ranges and densities in the UMR navigation pools. To achieve this goal, we are recommending specific and consistent light-related water quality criteria be adopted by water quality management agencies having jurisdiction over the UMR that will be protective of SAV growth and reproduction. These criteria are needed for monitoring, assessing impairments, formulating river and watershed management strategies, and evaluating management efforts that seek to enhance and protect SAV beds in the UMR. We believe consistent and scientifically based criteria are necessary to help target river or watershed sources contributing to excessive turbidity or suspended particulate matter concentrations in the river. These efforts may not only help sustain and enhance SAV communities but will also help achieve goals to reduce other sediment-related impairments on the river (UMRCC 2000).