Nutrients are essential to the vitality of our coastal ecosystem. Nutrients, in particular phosphorus and nitrogen, support the growth of aquatic plants, which in turn provide food for the fish, shellfish, and other organisms that live in our coastal waters. An excess of nutrients can result in a decline in aquatic plants and wildlife, negatively impacting these coastal ecosystems. Nutrients come from a variety of sources, including natural and anthropogenic sources. Anthropogenic sources can include septic systems, fertilizer application, and stormwater runoff.
In 2001, the Massachusetts Estuaries Project (MEP) was created to help determine current nitrogen loads to southeastern Massachusetts estuaries and evaluate reductions that would be necessary to support healthy ecosystems. The MEP is a collaborative effort between MassDEP, UMass Dartmouth, and southern Massachusetts communities. MEP evaluations will be completed for approximately 70 coastal embayments in southern Massachusetts.
The MEP uses a linked model to evaluate nitrogen inputs to estuaries. This information is used by MassDEP to develop Total Maximum Daily Loads (TMDLs) for each estuary studied. TMDLs calculate the maximum amount of a pollutant (nitrogen in this case) that a waterbody can assimilate and still support a healthy ecosystem (i.e., meet surface water quality standards and support public health). The MEP also provides technical guidance to support appropriate wastewater, watershed, and embayment management techniques to reduce nitrogen loading. This technical guidance is being used by communities to support the development of Comprehensive Wastewater Management Plans (CWMPs).