MS4 Stormwater Crediting Technical Assistance

Tracking and Accounting in the Blackstone and Ten-Mile River Watershed

MassDEP and RIDEM along with EPA Region 1 have begun to define areas of coordination that can directly benefit the region and their shared waterbodies. Rhode Island and Massachusetts surface waters have both significantly suffered from development and urbanization. In both states, many water bodies are impaired and/or have Total Maximum Daily Load (TMDL) plans. For many TMDLs, water quality improvements are expected as communities and developers install stormwater retrofits and incorporate stormwater management systems into new developments and redevelopments as part of MS4 permitting. MS4 permits require communities to track the installation, operation, and maintenance of various types of stormwater retrofits and green infrastructure, collectively known as stormwater management strategies. Once installed, communities must account for the pollutant removal that is achieved through each stormwater management strategy using the crediting system developed through the permitting process. In unison, this concept is known as “tracking and accounting” and is an integral part to creating a link between stormwater management strategy operation and water quality improvements. However, an outstanding question remains on how to best track and account for retrofits and stormwater management strategies to ultimately determine whether this collective action among towns makes improvements towards water quality. 

For this project, RIDEM, MassDEP, and EPA propose to carry out a pilot project that involves capacity building for implementation of stormwater management strategies as well as the tracking and accounting of pollutant reductions. The objective of the work is to 1) create a collaborative environment between a total of up to two municipalities from each state, that allow for capacity building around tracking and accounting of stormwater management strategies, 2) allow for information exchange on what metrics are required to build a consistent  and reliable regional approach to tracking and accounting mechanisms, and 3) create a sharable tracking and accounting model that can be applied to additional watersheds and states in the region. By involving municipal partners and inviting representatives from the Departments of Transportation from Rhode Island and Massachusetts, RIDEM, MassDEP, and EPA hope to develop the following goals: 1) share a multi-permittee approved set of metrics that help in the implementation of a tracking and accounting model, 2) development of agency and peer-led workshopping and training materials that can be distributed to other communities and states for implementation in other watersheds, and 3) create a draft set of requirements that helps shape an associated tracking and accounting database that can be set up in the region.

The regions selected for this program are the Blackstone River watershed and the Ten-Mile River watersheds. Both watersheds consist of MS4 municipalities: The permit is administered by RIDEM in Rhode Island under the RIPDES program while in Massachusetts the 2016 MS4 permit is administered jointly by EPA Region 1 and MassDEP but will be issued separately going forward.

Copy of Solicitation:
Solicitation for Interstate MS4 Stormwater Crediting Technical Assistance (PDF)

Program Description: 
Tracking and Accounting in the Blackstone and Ten-Mile River Watershed (PDF)

More Information:
Q&A Solicitation Document (PDF)
Submit any additional questions to James Houle, Director of the UNH Stormwater Center, at