Situated in northeast Rhode Island, the town of Cumberland sits in the Blackstone River Watershed. Since 2005, Woodard & Curran has provided ongoing water engineering services to the town, encompassing numerous projects related to water supply, treatment, and distribution. As part of this long-standing partnership, Woodard & Curran conducted a water supply evaluation that led to a creative solution enabling the town to save money while continuing to reliably supply roughly 23,000 residents with high quality drinking water.
Approaching 70 years of service, Cumberland’s surface water treatment facility struggled to meet increasingly strict permit and residuals discharge requirements, as well as growing water demand in the community. The combination of old infrastructure, state, and federal regulatory measures, and rise in population is a common problem facing water utilities across the country. Faced with these challenges, Woodard & Curran’s drinking water experts proposed switching from a combined surface and groundwater system to a wholly groundwater-based system by adding new well supplies that would avoid costly reservoir treatment upgrades, improve resiliency, and provide higher quality drinking water.
The project team needed to determine the feasibility of withdrawing 1.1 million gallons per day (MGD) from new groundwater sources to offset the amount of surface water supplied by the Cumberland Water Department, as well as to limit the quantity of water purchased from an adjacent system. Engineering and hydrological assessments were conducted at several potential groundwater source areas in town. Site screening, selection, and evaluations of soils and the aquifer helped narrow the possibilities to two sites where the team conducted small diameter test well programs. With the test well program providing promising results, Woodard & Curran developed and implemented short- and long-term pumping tests to fully evaluate groundwater supply availability, determine minimal environmental impact, and receive regulatory approvals. Additionally, the team evaluated source water blending and composition to assess potential impacts on corrosivity due to source water change. This helped the team model blending from the original and proposed water sources to predict water quality at representative households across the system. The resulting data was used to demonstrate to regulators that corrosivity would decrease due to sourcing solely from gravel packed wells.
With regulatory approval obtained for the new wells, Cumberland contracted with Woodard & Curran to complete conceptual and final design, bidding, and engineering services during construction including contractor oversight. The scope included facilities for the two new gravel packed wells and associated pumps, chemical addition for pH adjustment and corrosion control, disinfection to provide 4-log virus inactivation, fluoridation, and a standby generator as an emergency power source. The facility is equipped with telemetry for remote monitoring, alarming, and control, and tied into the town’s existing Supervisory Control and Data Acquisition (SCADA) system.
With the new wells in service, rather than investing significant capital in costly upgrades or total replacement of the town’s existing surface water treatment plant, they were able to decommission the facility. The gravel packed wells produce high-quality water that only requires chemical treatment before distribution. Rather than spending multiple millions on the aging plant, this approach will save the town hundreds of thousands of dollars annually. In fact, the project costs will be recovered in a matter of a few years with expected savings in the tens of millions over the life expectancy of the wells.
The Metcalf Franklin Farm is a historic site in the town of Cumberland, and it just so happens to be where Woodard & Curran’s project team identified the best site for gravel packed wells and associated treatment facility. The farmhouse and barn with freshly tilled soil, pictured left, served as the design inspiration for the treatment building. The team included cedar siding and copper gutters to help the facility blend in to the historic setting.
The new wells and chemical addition facility are located on a historic site within the town. In collaboration with the Water Department, Woodard & Curran facilitated extensive public outreach to engage abutters, a citizen’s oversight association, the State Historical Commission, the Department of Environmental Management, and Department of Health during the design process. This helped inform the facility’s design, ensuring it matched the historical aesthetic of the area and addressed all stakeholder concerns.
The outreach also helped educate ratepayers about the capital expenditure and the town’s return on investment. This helped community members understand that not only would the groundwater supply be more reliable than the town’s existing sources, but it could also help mitigate future rate hikes due to the long-term cost savings the project would realize.