Fresh Water Flow

On average, more than two billion gallons of fresh water flow into Narragansett Bay daily from its drainage basin or watershed—through major rivers such as the Blackstone, Taunton and Pawtuxet; smaller streams such as the Ten Mile and Hunt; and through ground water. These flows are critical components of the region’s fresh water habitats, and contribute to the Bay’s estuarine habitats as well.

The Narragansett Bay Region has abundant freshwater resources, but some areas are showing signs of stress linked to human withdrawals—for example, changes in riverine fish communities caused by low summer flows, and changes to wetlands caused by drawdown of local water tables by public wells.

According to the R.I. Department of Environmental Management (RIDEM), the following Rhode Island watersheds are showing flow stress:

Wood-Pawcatuck watershed, Chipuxet sub-basin. Private and public wells withdraw water for a variety of uses, including drinking water supply for several public water systems and the University of Rhode Island and irrigation for South County turf farms. A significant portion of the total water withdrawn is exported out of the basin via sewer systems that discharge directly into the Atlantic Ocean. According to USGS, the combined water withdrawals can exceed the river’s capacity.

Hunt River. Three public water suppliers withdraw water from the Hunt-Annaquatucket-Pettaquamcutt (HAP) aquifer. Extreme low flows occurred in the lower Hunt river during 2005 and 2007 and impacts to fish populations have been documented by RIDEM studies.

Initial analyses by RIDEM suggest that water withdrawals in Westerly, Jamestown, the Annaquatucket area of North Kingstown, Cumberland and Woonsocket warrant further evaluation to address the potential for withdrawals exceeding levels considered sustainable.

Massachusetts has developed the River Instream Flow Stewards (RIFLS) program to help local groups identify, document and restore rivers and streams suffering from abnormally low flows. They identify the following areas as impacted by low flow:

Blackstone River watershed. The mainstem of the Blackstone River in Rhode Island has adequate water which is supplemented by the discharge from the Worcester and Woonsocket wastewater treatment plants. But many reaches of the rivers and streams throughout the upper Blackstone watershed in Massachusetts suffer from unusually low stream flows due to human activity.

Taunton River Watershed. In summer, 2002, several tributaries of the Taunton were found to be completely dewatered by withdrawals.

Palmer River due to inter- basin water transfer out of Shad Factory Pond into the Kickemuit Reservoir in Warren, R.I.

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