Our Stormwater Management Program

Blackstone River

In Rhode Island, the R.I. Department of Environmental Management is the delegated authority to implement the National Pollutant Discharge Elimination System (NPDES) program through a similarly named program called RIPDES (Rhode Island Pollutant Discharge Elimination System). These programs require us to obtain permits and establish a stormwater management program aimed at reducing pollutants that enter drains and storm sewer systems.

The Federal government considers our network of drainage structures as a system, and therefore we are regulated as an MS4 (shorthand in the regulatory world for "municipal separate storm sewer system") and must comply with all permitting regulations.

Both NPDES and RIPDES require us to identify Best Management Practices (BMPs) for the six minimum control measures listed below in order for us to be in compliance with all stormwater regulations.

Stormwater Linear Manual & Related Documents

2018 Aquidneck Island SCPs

Public Education and Outreach on Stormwater Impacts

Permit Requirement

We must implement an ongoing public education program over the term of the permit. The goal is to provide information about the impact of stormwater discharges to water bodies while highlighting steps and/or activities you can take to reduce the pollutants in stormwater runoff.

Best Management Practices (BMP)

We will focus educational efforts toward municipal and state officials working on implementation of Stormwater Management Program Plans (SWMPPs). Working with the University of Rhode Island Cooperative Extension, we provide funding for training as well as the development of a coordinated public education message. This effort includes education of our own personnel and practices to better control stormwater and erosion. Our public education and outreach program has been recognized by the U.S. Environmental Protection Agency as being exemplary.

Public Involvement and Participation

Permit Requirement

All public participation/involvement activities must comply with state and local public notice requirements.

Best Management Practices (BMP)

The general public will have the opportunity to comment on the annual Stormwater Management Program reports that will be available for review and comment. If we receive more than 25 requests for a public hearing during the comment period, we will schedule one. During this process, comments also will be accepted for suggested stormwater management program amendments.

Illicit Discharge Detection and Elimination

Permit Requirement

We must develop, implement and enforce a program to detect and eliminate illicit discharges or flows. The management program must include a storm sewer system map showing the location of all outfalls (the point where a waste stream discharges into a body of water) and the names of all waters that receive these discharges. The map also will show the location of catch basins, manholes and pipes within the system, physical interconnections with other regulated MS4s and private property connections. Our program plan must contain procedures to identify and target priority areas and locate and remove illicit discharges.

Best Management Practices (BMP)

We will use a combination of summer interns and hired vendors to identify, map and describe all stormwater outfalls. We review construction design plans to locate these features, and when plans are not available, we physically follow the pipe to its outfall.

During our outfall identification and location process, we survey them for dry-weather discharges to potentially identify illicit connections to our system. We sample them for temperature, pH, conductivity, and bacterial contamination, as required by the general permit. Our investigation sometimes requires us to trace flows up the pipe to identify where it's coming from, using smoke or dye testing or video as needed. If we find an illicit connection we work with the responsible party and RIDEM to remove it.

The general permit requires that to the extent allowable under state law, we must prohibit and enforce unauthorized non stormwater discharges into the system. While we don't have the authority to establish such ordinances, we rely on RIDEM for enforcement.

Construction Site Stormwater Runoff Control

Permit Requirement

We must develop, implement, and enforce a program to reduce pollutants in any stormwater runoff to the MS4 from construction activities that result in a land disturbance of greater than or equal to one acre. We must also include disturbances less than one acre if they are part of a larger common plan. At a minimum, the program must be consistent with the requirements of the RIDEM RIPDES general permit for stormwater discharge associated with construction activity.

Best Management Practices (BMP)

To fulfill goals outlined in our Stormwater Management Program Plan (SWMP), two StormWater Pollution Prevention Plan (SWPPP) templates have been developed for use on RIDOT construction projects. Correct and complete use of these templates will help meet the requirements of the RIDPES construction general permit and/or the Minimum Measure 7 requirements under the 2010 RI Stormwater Design and Installation Standards Manual.

Please visit Environmental Permitting drop down under the RIDOT Environmental Division for templates.

Post-Construction Stormwater Management in New Development and Redevelopment

Permit Requirement

We must develop, implement and enforce a program to address stormwater runoff from new development and redevelopment projects that disturb greater than or equal to one acre, including projects less than one acre that are part of a larger common plan of development or sale that discharge into the MS4. The program must ensure that controls are in place to prevent or minimize water quality impacts.

Best Management Practices (BMP)

Currently, all new projects planned by us are designed in accordance with the Rhode Island Stormwater Design and Installations Manual, which provides guidance on the design, construction and maintenance of stormwater management systems. At a minimum, stormwater management systems for new projects are designed to realize the maximum sediment retention possible - with at least 80 percent of suspended solids removed before discharge into a body of water. For rehabilitation and reconstruction projects, we strive to provide the maximum water quality treatment possible.

We also strive to improve our maintenance of stormwater systems, including regular cleaning of detention basins and swirl-chamber units.

Pollution Prevention/Good Housekeeping for Municipal Operations

Permit Requirements

We must identify all operations that have a point source or the potential for a point source discharge of stormwater to an MS4 or a body of water. From this, we must develop and implement a program to reduce pollutant runoff, including inspection procedures and schedules, and to develop and maintain an employee-training program for good housekeeping and pollution prevention.

Best Management Practices (BMP)

We have identified existing programs that met the requirements of the general permit, and reviewed various methods to improve pollution prevention. Proposed programs include more frequent sweeping, anti-icing management programs, and better inventory and inspection schedules of stormwater features, including basins, swales and eroding road shoulders. Stormwater management is a key focus of our winter training programs.

RIDOT Road-Stream Crossing Assessment Handbook

The Rhode Island Department of Transportation (RIDOT) has developed a Road-Stream Crossing Assessment Handbook In collaboration with Fuss and O’Neill and members of a stakeholder group. This handbook is intended to serve as a guidance document and decision-making tool to identify road-stream crossings in Rhode Island that should be prioritized for replacement or upgrade. A pilot study of the Woonasquatucket River watershed in northern Rhode Island is included in Appendix H of the Handbook.

Download Assessment Handbook

RIDOT Road-Stream Crossing Assessment Public Map

If you are interested in using the RIDOT Road-Stream Crossing Assessment Handbook for field data collection and assessments, please contact RIDOT’s Natural Resources Unit for guidance and supplemental materials.

Stormwater Coordinators in Rhode Island

RIDOT Stormwater Control Plan

MAY 2019

RIDOT has developed a set of templates and guidance documents for the development of the RIDOT Stormwater Control Plans. These plans are watershed-based and are a requirement of the Consent Decree.

Stormwater Quick Links

Know Where it Goes!


Reports & Plans

Stormwater Consent Decree

RIDOT is pledging more than $100 million over a 10-year period to ensure compliance with the Clean Water Act and a number of remedial measures under a consent decree with the Environmental Protection Agency. This initiative will reduce pollution from stormwater flowing into Narragansett Bay and hundreds of lakes, ponds and rivers throughout Rhode Island.

Download Consent Decree

This project was undertaken in connection with the settlement of an enforcement action, United States v. Rhode Island Department of Transportation, taken on behalf of the U.S. Environmental Protection Agency under the Clean Water Act.