Infrastructure Projects

System improvements, upgrades and projects

We are continuously working to maintain and improve the water system.  Some of the major projects we are currently working on involve the installation of new, or the replacement of existing, equipment and facilities needed to provide safe, reliable water service.

workers building pipe trench

Well 22

Nov 20, 2019 New Hampshire

Project Goals and Objectives

Increase water system production capacity by developing a new well. This additional capacity is needed to support projected growth in Hampton and North Hampton.

Scope of Work

Well 22 is a bedrock well located in Hampton.  Pumping tests show that it has a production capacity of more than 800 gallons per minutes (more than 1 million gallons per day).

A Large Groundwater Withdrawal Permit from the NH Dept. of Environmental Services (DES) is required for a new well. Improvements to chemical treatment facilities are also planned (see Little River Road Water Treatment Plant).

Installation of a pump and pipes connecting it to the distribution system have been completed.

Production_Capacity_of_Wells

Schedule

The permit application was submitted to DES on April 26, a final permit is expected in December.

Current Status

A permit is expected from NH DES in December.

Summary of Well 22 Pumping Test

The purpose of the pumping test was to determine the production capacity of the new well; identify any adverse impacts on neighboring wells, wetlands and surface waters; and collect water quality data to assess potential treatment. The full 494 page report can be viewed here.  A few specific references are cited below.

Pumping

The pumping test was conducted between June 20 and July 17, 2018 at an average pump rate of 825 gallons per minute, or 1.2 million gallons per day.  Water level in Well 22 dropped to 177 feet below ground level during the pumping test, and remained above the level of the water bearing fracture (220 feet below ground level) for the duration of the test (see page 151 of the report).

During the pumping test, water levels were monitored in two dozen private wells in the area (see Figure 6 on page 65).  The “Cone of Depression” (where water levels changed in response to the pumping test) is actually an oblong zone that clearly aligns with the underground bedrock fracture, running northeast to southwest roughly parallel to Woodland Road.  Drawdown levels ranged between 10 to 30 feet in this zone.  None of these changes were determined to be an adverse impact, as the levels remained high above the depths of existing well pumps.  Other wells outside of this zone showed no changes during the pumping test.

Monitoring devices installed in wetlands and surface waters surrounding Well 22 showed no water level changes during the pumping test.

Water quality

Salt water intrusion is deemed to be extremely unlikely.  Salinity levels (see Table 7 on page 55) measured in multiple wells in the area during the pumping test showed no observable changes.  Hydrogeoloic calculations based on the pumping test data show that the depth to saltwater interface ranges from 300 feet below sea level beneath wells located near the shoreline (which showed no changes during the pumping test), to 2,000 feet below sea level at higher elevations.

Other water quality results show few parameters of concern.  Most regulated contaminants were not detected (Table 8 on page 56), except for trace levels of a few regulated minerals that commonly occur in groundwater.  Of particular note, water from Well 22 is “softer” than other wells, meaning it has lower total concentration of natural minerals.  Lower mineral concentrations are beneficial because it reduces the amount of soap used for cleaning, and causes less spotting on glassware.

Arsenic levels are about the same as maximum regulatory levels, and so may require removal.  More arsenic data is being collected and, if necessary, treatment will be incorporated into the new facility being designed for Wells 7 and 22 (see Little River Water Treatment Plant).

Trace levels of some PFAS compounds were also observed and are comparable to levels in the company’s other bedrock wells.  They currently are well below proposed regulatory levels for PFAS, so no treatment is being considered at this time.