How will removing the dam affect water levels in the river?

Removing the dam will not change (neither raise nor lower) water levels downstream of the Potter Hill Mill site during normal or storm/flood flows.

Upstream of the dam’s current location, the extent that water levels will be lowered depends on how far a location is upstream; water levels will be lowered more closer to the Potter Hill dam site, and the magnitude of reductions will diminish at locations further upstream of the dam.

Approximate water level reductions in respective segments of the river are summarized below, for different (seasonal and flood) flow conditions.

● Immediately Upstream of Potter Hill Road Bridge
○ Average Seasonal Low Flow (August – October): 6.5 feet
○ Average Spring Flow (March – June): 6.3 feet
○ 100-Year Flood Flow: 2.5 feet

● Immediately Downstream of Route 3 Bridge
○ Average Seasonal Low Flow (August – October): 4.25 feet
○ Average Spring Flow (March – June): 3.9 feet
○ 100-Year Flood Flow: 1.7 feet

● Immediately Upstream of Route 3 Bridge
○ Average Seasonal Low Flow (August – October): 4.1 feet
○ Average Spring Flow (March – June): 3.7 feet
○ 100-Year Flood Flow: 1.3 feet

● Pawcatuck River at McGowan Brook (Aguntaug Swamp) Outlet
○ Average Seasonal Low Flow (August – October): 3.5 feet
○ Average Spring Flow (March – June): 2.4 feet
○ 100-Year Flood Flow: 0.6 feet

● Bradford Fishway
○ Average Seasonal Low Flow (August – October): 1.4 feet
○ Average Spring Flow (March – June) 0.9 feet
○ 100-Year Flood Flow: 0.1 feet

Show All Answers

1. Why is the dam being removed?
2. Could the dam be repaired or partially removed?
3. Could a design similar to that of the Bradford fish passage project be used for the Potter Hill project?
4. What alternative designs have been considered and why was the proposed design selected?
5. What safety hazards are associated with the mill and dam structures?
6. How will removing the dam affect water levels in the river?
7. Will my household well be affected?
8. Many properties along the Pawcatuck River have private drinking water wells, especially on the Hopkinton side of the river. How many homeowners’ wells could be affected by the predicted drop
9. Will Westerly’s municipal water wells adjacent to the Pawcatuck River be affected?
10. How will removing the dam reduce flood risk to upstream and downstream properties? Will larger flood events (i.e., the 500-year recurrence flood) be worse upstream or downstream following dam removal?
11. Will removal of the dam cause increased flooding to downstream areas, including downtown Westerly?
12. How will removing the defunct dam and mill affect public access to and uses of the river?
13. How will removing the dam affect fish and wildlife?
14. How will removing the dam affect wetland systems upstream of the dam?
15. Is the proposed design accounting for climate change projections and worst-case future hydrologic scenarios?
16. Who is the project team?
17. What are the next steps?
18. Where can I get more information on the project?