Forest land cover as a tool in water quality management: Developing a valuable addition to the Cape Cod Commission’s 208 Technologies Matrix

Grant Award Year: 
2018-2019
Ivan Valiela
Javier Lloret
Research Description: 
To protect quality of fresh and estuarine waters the Commonwealth of Massachusetts has issued regulations requiring reductions of nitrogen loads in every coastal municipality. Cost of conventional sewage treatment plants is currently prohibitive, so there is growing interest in assessing the potential of alternative options for controlling nitrogen loads. The Cape Cod Commission has assumed a leading role in compiling assessment and potential application of available alternative options, and reaching out to transfer the information to a diverse variety of stakeholders, agencies, and managers, by creation of a site that contains a Technical Matrix where information about options is provided. Because there is active research and application of the various options, a review committee considers updating the Matrix at intervals. During a recent review, it became clear that the Matrix needed to include a section of nitrogen retention by forested land covers. We hypothesize that forests provide significant water quality subsidies because forest intercept large fractions of nitrogen inputs, and because atmospheric deposition is the largest source of nitrogen to the surface of watersheds in Cape Cod. The water quality subsidy provided by forested tracts, however, is threatened by the persistent loss of forest area that follows growing urbanization in Cape Cod and elsewhere. These facts suggested the need to add a section to the Matrix that allows assessment of the potential N retention likely by management, restoration, or maintenance of forests. The core goal of this proposal is to quantify the potential of forested land cover management to reduce N loads to fresh- and N-sensitive coastal waters, and develop a section of the Matrix that conveys that assessment and its application to the Cape Cod region.