Status of Island Waters Aquidneck Island, Rhode Island Aquidneck Island Planning Commission May 2018 This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement SE00A0136 to Aquidneck Island Planning Commission. The contents of this document to not necessarily reflect the views and policies of the Environmental Protection Agency, nor does EPA endorse trade names or recommend the use of commercial products mentioned in this document. 1 What is the Island Waters Project? Aquidneck Island’s fresh and saltwater resources are immensely valuable – for drinking water, recreation, our communities’ quality of life and as the foundation of our coastal economy. Yet the Island’s geography, geology and land use make these waters vulnerable to pollution from stormwater runoff. The Island’s lands and waters are shared by three communities: Newport, Middletown, and Portsmouth, Rhode Island, as well as Naval Station Newport. Water flows freely across municipal boundaries, and all three communities contribute to stormwater runoff, while all three experience the impacts of pollution to fresh and salt waters: beach closures, shellfishing bans, and threats to the Island’s drinking water supply. Aquidneck Island is the only East Coast island that relies almost entirely on surface reservoirs for its drinking water, and all three communities are home to high-quality public saltwater swimming beaches. Island Waters is a new program to help the communities of Aquidneck Island restore clean water by working together to effectively manage stormwater pollution. The program was developed by the Aquidneck Island Planning Commission (AIPC) in partnership with Newport, Middletown, Portsmouth, and the non-profit organizations Clean Ocean Access (COA) and the Aquidneck Land Trust (ALT). Other participating partners include the Eastern Rhode Island Conservation District (ERICD), the Rhode Island Departments of Environmental Management, Transportation, and Health (RIDEM, RIDOT and RIDOH, respectively), and the Rhode Island Green Infrastructure Coalition. In September 2016, the U.S. Environmental Protection Agency (EPA) selected Island Waters for funding with a three-year grant under its Southeast New England Program (SNEP). This report is part of the first phase of the Island Waters project and provides a summary of the status of waters on and around Aquidneck waters, including current water quality. The report also provides an update on municipal efforts to manage stormwater through municipal separate storm sewer systems (MS4s), and a synthesis of prior studies and existing plans for potential stormwater best management practices (BMPs). Taken together, the elements of this report are intended to provide the communities and stakeholders of Aquidneck Island with a better understanding of stormwater impacts on the Island’s water resources, while pointing toward effective solutions that can be implemented by the Island Waters program, as well as independently by the communities and other stakeholders. Status of Island Waters –May 2018 1-1 1-1 What We Will Accomplish The goal of Island Waters is to assist the communities and stakeholders of Aquidneck Island in restoring fresh and salt waters by reducing polluted stormwater runoff to the Island’s reservoir system, other fresh water bodies, and local coastal waters. We’re focusing initially on some of the principal threats to the Island’s drinking water and swimming beaches – nutrients (fertilizers such as nitrogen and phosphorus) and bacteria. Island Waters is producing real and immediate improvements to restore clean water on Aquidneck Island, while establishing a framework for better stormwater management in the future. Together, the Island Waters partners are: Investing roughly $1 million in stormwater improvements Island-wide; Protecting Aquidneck Island’s drinking water system; Reducing direct pollution sources to coastal waters; Engaging and informing Island residents about watershed stewardship; Assisting Island municipalities in identifying funding sources for clean water; and Sharing results with other communities in New England and beyond. Ultimately, it is the intention of Island Waters to serve as a basis for increasingly integrated water resources and habitat planning, policy, and implementation, including the development of sustainable funding mechanisms for water quality management. Working together, the communities of Aquidneck Island can reduce stormwater pollution more effectively, at lower cost, than by addressing the problem individually. Moreover, we hope that Island Waters will serve as a model for communities throughout New England and elsewhere in the U.S. This report is a foundation for the entire Island Waters project. By understanding the status of Island water quality and the work done to date to develop BMPs, we will develop a foundation for identifying and implementing the most beneficial and cost-effective solutions to reduce stormwater pollution to Aquidneck Island’s fresh and salt waters. Why This Matters Aquidneck Island’s surface, ground, drinking, and coastal waters are closely interconnected and highly vulnerable to nutrient and bacterial pollution. Nutrients spur algal blooms, including blooms of potentially toxic cyanobacteria that have appeared in the Island’s reservoirs in recent years, increasing threats to both drinking water and recreational waters. Fecal coliform and enterococcus bacteria are indicators of human pathogens – disease-causing organisms that can make people sick when present in swimming or shellfishing waters. Nutrients and bacteria are carried by stormwater from homes, farms, roads, parking lots and public lands into the Island’s rivers, streams, reservoirs, and coastal waters. Water bodies that exceed state pollution standards are classed as “impaired” by the RIDEM. Aquidneck Island’s reservoirs are all impaired for nutrients and its principal streams will soon be listed as impaired; groundwater wells also exhibit high levels of nitrates. Coastal waters are locally impaired for nutrients and bacteria, and marine beach closures on the Island typically occur several times over the course of a summer. 1-2 Status of Island Waters – May 2018 The City of Newport, which manages the drinking water system that serves nearly 70,000 residents of Aquidneck Island, has done a great deal in recent years to ensure safe drinking water for all Island reservoirs, including the construction of a state-of-the art water treatment plant at Lawton Valley Reservoir in Portsmouth. However, stormwater runoff is an ongoing stress to the system and must be reduced in order to reduce threats to drinking water, and to maintain the long-term viability and quality of the Island’s shared drinking water system. Since passage of the Clean Water Act in 1972, pollution to Narragansett Bay and other Rhode Island coastal waters has been dramatically reduced, largely due to improved wastewater treatment and the elimination of combined sewer overflows. However, “non-point” sources of pollution such as stormwater have proven more difficult to control and are now a principal source of pollution to coastal waters. Since stormwater originates from nearly all types of land use on Aquidneck Island – public and private, homes and farms, roads, roofs, parks and parking lots – and affects virtually all of the Island’s fresh and salt waters, an integrated approach is needed to effectively and efficiently address the problem. Island Waters provides such an approach, in order to ensure that Aquidneck Island’s fresh and salt waters continue to serve as the foundation for a healthy environment, prosperous economy and high quality of life – now and in the future. Status of Island Waters – May 2018 1-3 1-3 2 Aquidneck Island Waters Aquidneck Island, the largest and most populous island in Narragansett Bay, has multiple, interconnected water resources. The Island can be divided into five watersheds or drainage basins (Figure 2-1); within these watersheds, water flows into fresh water streams, public water supply reservoirs, and Narragansett Bay (Figure 2-2). The interconnected nature of water resource issues on Aquidneck Island highlights the need for regionally coordinated efforts to improve water quality and habitat integrity that the Island Waters project is uniquely positioned to address. 2.1 Hydrology - Coastal Waters Aquidneck Island is located at the southern end of Narragansett Bay. The Island is bounded by the Bay’s East Passage on its western shore and the Sakonnet River (which is another passage of the Bay) to its east. The northern end of the Island lies along the shore of Mt. Hope Bay (a sub-estuary of Narragansett Bay), and its southern shore borders Block Island Sound and the Atlantic Ocean. (Figure 2-1). Public swimming beaches are located in all three Island communities, but mostly on the southern and eastern shores of the Island. 2.2 Hydrology - Inland Waters As noted above, Aquidneck Island is made up of five watersheds (Table 2-1), all of which drain to Narragansett Bay, the Atlantic Ocean, or the Sakonnet River (Figure 2-1 and Figure 2-2). These larger watersheds contain smaller subwatersheds that drain the area of land contributing to an individual waterbody, such as a lake or stream. A drumlin – a landform composed of dense glacial till - runs along much of Aquidneck Island. This dense till material acts as a horizontal barrier preventing shallow groundwater from infiltrating to a deeper aquifer. The three municipalities