Partnership aims increase Portsmouth’s resiliency from sea level, groundwater rise
Rising ocean levels and stronger storm patterns have caused coastal cities to take notice of the water they share with the earth. It’s the reason the city of Portsmouth, N.H.’s, Department of Public Works has partnered with HydroPredictions, the New Hampshire Department of Environmental Services, the University of New Hampshire and Jennifer M. Jacobs and Associates, LLC, on an innovative groundwater monitoring project.
“We are a coastal town with old infrastructure and historical buildings. We are the only active port in New Hampshire,” explained Christopher Vakili, the city’s stormwater and water quality specialist. “We have a deep relationship with the sea.”
However, he added, until about a dozen years ago there was not much conversation about water quality and the interaction of the sea with the built environment.
That’s about the time the University of New Hampshire began to map the effects of the sea on the area around Portsmouth. UNH set up a monitor at the city’s Strawberry Banke Museum, a 10- acre site located at the lowest point in town.
The team placed a tidal gauge at the city pier to monitor the rise and fall of the tides not just during storm surges but as the everyday rhythm of coastal life. These monitors, Vakili said, helped scientists to better understand the relationship between sea level and ground water.
The studies led to the recent partnership that will use Portsmouth as a model by assessing groundwater levels, water, sewer and stormwater infrastructure. The city is also looking at the vulnerabilities the built environment face from to sea level rise. Vakili said the studies are benefitting not only Portsmouth but other cities that experience similar conditions.
The current collaboration includes consultants in climate change adaptation, water quality and coastal road infrastructure.
A project proposed by the partnership will install 10 small shallow groundwater monitoring wells about 20 feet deep at highly susceptible sites. Because using city land makes maintaining the wells more manageable, the sites will be on school and city park property as well as a couple of other city-owned sites.
The locations were chosen based on a number of factors that included groundwater rise simulations; mapping studies using LiDAR, a laser light that measures distances; accessibility of the site where wells are located and the avoidance of utility lines, Vakili said.
The wells were funded by grants obtained by the University of New Hampshire and will be maintained by Portsmouth’s Department of Public Works.
Each well has four-inch steel protective casings and concrete anchor pads. Drilling work began in early October and wells have been located at various distances from the water to monitor both tidal impacts and to assess groundwater changes further inland.
Vakili pointed out that when there is drilling there are always obstacles, such as the difficulty of drilling into rock. As of mid-December, the city was able to complete seven wells.
By identifying vulnerable areas for rising groundwater and surface-water flooding, Portsmouth can protect existing city infrastructure and include adaptative planning in future maintenance, design and construction projects. The city had partnered earlier with the University of New Hampshire and Strawberry Banke Museum for real-time monitoring of groundwater fluctuations at several sites in the South End, and Vakili said the monitors at the museum allow visitors to see water levels in real time.
He added that Portsmouth has a history of being proactive about its relationship to the sea. “We have been concerned about what sea level rise is going to do to our city and the infrastructure. We’ve tried to estimate how high the water can get in certain areas.”
The city wants to be certain that its buildings have good structural integrity, since flooding has reached as high as 18 feet.
“We have to take into consideration king tides and storm surges. Portsmouth, New Hampshire is a bit of a guinea pig so that we can plan better for the future.”
Settled in 1600 and incorporated in 1630, Portsmouth has a population of about 22,000 residents but swells with a working population that commutes into the city. Add to that the tourists who are a big part of Portsmouth life from May to September, as well as the “leaf peepers” who visit during the autumn months. All of this provides an incentive to protect the natural environment and the historic buildings that attract the visitors.
The groundwater monitoring project is part of a broader effort to inform and assist U.S. coastal cities and towns in increasing their resiliency from utility and infrastructure impacts caused by climate-driven increases in both seawater and groundwater levels.
Unlike seawater, which is readily visible, groundwater is the water below the surface of the land that is replenished by rain and melting snow seeping into the ground. Vakili said that to prevent damage from groundwater entering the city’s infrastructure, engineers have resorted to “clever redirecting.”
The wells also can help predict the beginning of a drought and can track its severity as conditions decline or improve.
Coastal U.S. cities are taking notice of the water they share with the earth. It’s the reason the Portsmouth, N.H., Department of Public Works has partnered on an innovative groundwater monitoring project. (Shutterstock.com) The 10 sites selected for groundwater monitoring wells in Portsmouth, N.H., were chosen for their location as well as the distance above the level of the Gulf of Maine and the 12-mile long tidal Piscataqua River that forms state’s border with Maine. (Map provided by Portsmouth, N.H.) 
The shallow groundwater monitoring wells are 20 feet deep and located on public land around the city. Installation of the wells was paid for by the University of New Hampshire. (Photo provided by Portsmouth, N.H.)
