Though we define the Narragansett Bay Region in fixed geographic terms, it can also be thought of as a dynamic interaction between fresh and salt water. Precipitation enters ground and surface waters, then flows downstream through wetlands, streams and rivers, meeting and mixing with oceanic waters in the estuaries of Narragansett Bay and the coastal ponds. The quality of fresh water throughout NBWE is, therefore, fundamental to the health of the entire ecosystem.

Much of the Narragansett Bay watershed is in Massachusetts, so this discussion of freshwaters includes rivers in both states. We also include all of Rhode Island’s rivers, lakes and ponds, even though some (e.g.: Wood and Pawcatuck) are not within the Narragansett Bay watershed.

According to the RI DEM assessment of water quality Rhode Island has approximately 1,498 river miles and 20,917 acres of lakes and ponds (measured at 1:24,000 scale). The Massachusetts assessment of water quality lists approximately 422 miles of rivers flow into Narragansett Bay with 21,613 acres of lakes and ponds (MA EOEA 2007). Groundwater is locally abundant and widely used with approximately 26% of the Rhode Island population supplied with drinking water from public and private wells (RIDEM 2008). Groundwater is closely connected to surface waters and during dry periods, water in rivers and streams is derived almost entirely from groundwater.