Groundwater supplies in the Pawcatuck River watershed are naturally governed by a number of factors, including the local geology, the availability of water supply recharge areas (where infiltration of rainwater occurs), the depth/condition of bedrock and in some cases, river conditions. Based on the project team’s preliminary assessment, the project team has determined that approximately 125 properties warrant further evaluation. Earlier this year, the project team sent a survey to potentially affected property owners; slightly fewer than 50 responses have been received by the Town of Westerly and its consulting engineer to date. Of those that have responded to date, a number of have indicated that their wells have previously experienced lack of water, or draw water from shallow sand formations saturated by river water.
In the coming months, the project team will continue to work with the towns of Westerly and Hopkinton to refine its assessment of private wells, based on the following criteria:
● depths below ground (i.e., deep and bedrock wells will not be affected)
● location with respect to the river (the higher the elevation and the greater the distance from the river, the lower the potential for effects)
● proximity to other tributaries and surface waterbodies and subsoil/bedrock conditions (these other sources reduce reliance on the Pawcatuck River for groundwater supply and more permeable/porous soils and fractured bedrock allow water to move underground to private wells more readily)
● type of well (certain types, like hand-dug wells, are more likely to be affected)
● record of performance (whether they have experienced lack of water during previous dry or drought conditions)
Even if no action is taken, in future years, wells that are affected by changes in river flows will have limited capacity to provide a reliable source of drinking water, as leakage rates through the Potter Hill dam’s failing millrace headgates increase river levels between Potter Hill Dam and Bradford will continue to drop as a result.
Further, scientists predict that as a result of climate change, Rhode Island will experience longer and more frequent periods of drought, that will put more stress on shallow, vulnerable wells, both in terms of water quantity and quality. When the headgates ultimately fail and the river breaches the dam through the millrace channels, these substandard wells will likely experience a sudden failure, with no plan or resources in place to replace the failed well in a timely manner.