Siting and directing installation and permitting of a filter-packed replacement well near existing pumphouse

Nobis worked closely with the Rollinsford Water and Sewer District and the District’s engineering consultant to assess options for the General Sullivan Well, a gravel-packed well installed in the 1950s that experienced declining yield and the frequent need for re-development despite reconstruction. The assessment indicated that further redevelopment would not be fruitful and that well replacement on the same site was the best option for the District.

Nobis oversaw both test drilling near the existing pumphouse to select the most favorable location for a replacement well and replacement well installation at that location. The replacement well is constructed with a filter pack consisting of glass beads, the first known example of this construction for a community well in New Hampshire. Nobis conducted a pumping test and other investigations to satisfy a streamlined permitting process for the replacement well, in close consultation with the New Hampshire Department of Environmental Services (NHDES). During the permitting process, Nobis recommended wellhead and aquifer protection measures to minimize risk to the aquifer at the General Sullivan Well site, which is located in a residential neighborhood.

challenges

  • The Rollinsford Water and Sewer District experienced declining yields from the General Sullivan well, requiring well rehabilitation with increasing frequency and decreasing effectiveness.
  • Declining yields required the District to rely increasingly on its other wells, which require expensive water treatment.
  • Developing a new water supply at another site would be an expensive and time-consuming process.

solutions

  • Nobis advised that continuing to redevelop and clean the General Sullivan well would not address insufficient water supply issues. Installing a replacement well on the site and using a submersible pump allows the District to continue using the site and the existing pumphouse at a manageable cost.
  • The replacement well solution provided the lowest-cost and quickest permitting pathway.
  • The replacement well solution allowed the District to reduce its dependence on the other two wells, which require expensive treatment, and thereby minimize long-term system operating costs.

results

  • A replacement filter-packed well was installed on the General Sullivan site, immediately outside the existing pumphouse.
  • Nobis conducted a pumping test and activities to address other requirements under the NHDES’ replacement well permitting rules and received approval for the District to connect the new well to the system.
  • The District installed a submersible pump in the replacement well, abandoned the original well, and connected the replacement well to the system.