Water Resources Research Act Program

Details for Project ID 2010MS110B

Sources, sinks, and yield of organic constituents in managed headwaters of the Upper Gulf Coastal Plain of Mississippi

Institute: Mississippi
Year Established: 2010 Start Date: 2010-03-01 End Date: 2011-02-28
Total Federal Funds: $12,704 Total Non-Federal Funds: $26,611

Principal Investigators: Jeff Hatten, Janet Dewey, Andrew Ezell

Project Summary: Forestland comprises the majority (64.85%) of the total land area in MS; primary forest-based industries (e.g. logging, forestry, primary wood products) represent an annual contribution of $11-$14 billion to the state economy and approximately 54,000 jobs. Much of the silvicultural activities upon which state economy depends occur in headwater catchments, thus silvicultural best management practices (BMPs) are designed to minimize forest-related non-point source inputs of sediment, nutrients, and pesticides. In many upland-forested watersheds, surface and subsurface flow are temporally and spatially connected with respect to physicochemistry and biotic communities, however the ecological linkages between headwaters and larger order perennial streams are poorly documented. In particular, the relationships among origin, storage, and consumption and export of organic matter (OM) with stream discharge and subsurface interflow represent significant gaps in our understanding of headwater processes. This proposal will address the transport and source/sink behavior of sediment, and dissolved and particulate forms of organic matter, in the form of nitrogen (N) and organic carbon (OC), over a broad range of hydrographic conditions and scales in small managed-forest watersheds. Understanding the source and transport of these compounds will allow us to better to determine what is “typical” and predict how forest management activities will affect sedimentation, N-capital, downstream ecosystems, pollutant transport, and C-cycling at ecosystem, regional, and global scales. Sediment, organic matter, and nutrients (particularly nitrogen) are the constituents that most often lead to the impaired designation for rivers in Mississippi. By understanding the usual (or typical) rates of delivery of sediment, carbon, and nitrogen, we will be able to constrain the natural variability in these constituents and advise the creation of TMDLs for impaired water bodies. Headwater streams are important in-terms of their contribution to water and nutrients to downstream fluvial environments. Many studies of non-mountainous systems have focused on the quantity of particulate or dissolved forms of material (e.g. suspended solids, organic matter, and nitrogen); few have examined the source of this material. We propose to concurrently examine both the quantity and source of particulate and dissolved organic matter. Utilization of the proposed small-watershed approach coupled with event sampling, may provide a reasonably reliable method to infer controlling processes of OM, nutrient, and contaminant cycling. This information will be of value to forested-watershed managers in their efforts to weight the environmental cost vs. nutrient cycling benefit of organic inputs resulting from silvicultural activities.