Residents of Southold Town are consuming water at an unsustainable level if the town intends to continue to rely on the freshwater aquifer beneath its soils, according to a new report by Peconic Green Growth evaluating 38,000 Suffolk County Water Authority (SCWA) and town records.
The report comes after SCWA gave presentations in Southold in the past several years on the strain of fluctuating demands on water supply and on saltwater intrusion into the drinking water supply.
According to Peconic Green Growth’s report, issued July 6, “we are already pumping at levels that could damage the existing resources. Simultaneously, the Town of Southold is facing pressures from development that caters to intense tourist and agrarian economies, as well as supporting a marine culture.”
Glynis Berry, an architect who serves as Executive Director of Peconic Green Growth, presented the report to the Southold Town Board at their July 17 work session.
“It kind of shocked me,” said Ms. Berry of her findings in a document that she had initially believed would serve primarily as an educational tool.
The report was funded with a grant from the Long Island Community Foundation, and makes use of both SCWA and private well data, along with U.S. Geological Survey data from 2016 that shows the groundwater elevation shrinking throughout the four separate segments of the Upper Glacial Aquifer that the North Fork relies on for its drinking water.
“In just six years, the Orient and East Marion five-foot groundwater contours have disappeared from a 2016 map documenting groundwater elevation, the deep section of the Cutchogue aquifer is not showing, and the deeper contours west of Mattituck Creek have pulled back from both the coast and the east,” said Ms. Berry, drawing on data from the U.S. Geological Survey.
“I think we’ve got a real problem here, because it’s so sensitive,” said Ms. Berry, “It’s not one continuous aquifer. It’s isolated segments.”
She pointed out that much of the public water supply on the North Fork is pumped out of wells in the center of the land mass, but is used near the residential developments along the coastlines, where it is more likely to travel toward surface waters than to recharge the aquifer from which it came.
“Thirty to 50 percent [of the water pumped] is lost at outdoor uses,” she said. “Sixty percent is used in the zero to two year discharge areas (near the shoreline), where the water is transported to the coast, and it won’t recharge the aquifer.”
The North Fork is also susceptible to saltwater intrusion into its drinking water supply, due to both the peninsular nature of its land masses and the fluctuations in water demand caused by the area’s seasonal economy, which can rapidly pull fresh water from wells, which is replaced by the salt water layer beneath the freshwater lenses we depend on for potable water, an irreversible process.
Ms. Berry added that, according to a 2011 study by national environmental consultants CDM Smith, “Long-Term Potable Supply in Southold, New York: Managing a Limited Freshwater Aquifer in a Largely Agricultural Region,” if seasonal demand for water is not curbed, by 2030 the aquifer will be 40 feet shallower than it currently is.
“Wetlands will be negatively impacted,” she added.
Ms. Berry added that in 2016 Southold residents were pumping 24 percent more water than they’d originally been projected to pump in 2030.
“We’re already way beyond what they were already saying was an untenable situation,” she said.
Currently, Southold residents are removing 2.6 billion gallons of groundwater annually, through both public and private wells, she said. The average summer use here is 559 gallons per household per day, 2.4 times the national average. But the median summer use is just 247 gallons per day.
“This means that people who are conservative in their water use are subsidizing the heavy users, as water rates are flat,” said Ms. Berry.
Using the data from the Suffolk County Water Authority, which supplies water to about half the properties on the North Fork, and linking the data to town assessment records, Ms. Berry also found a striking correlation between property values and water consumption.
Homes valued at less than $332,000 used just 253 gallons of water per day on average in the summer, but houses valued above $2 million used 2,511 gallons of water per day.
Ms. Berry said she had been expecting to find that irrigation was the primary source of the increase in seasonal demand, but had instead found that there are numerous factors — from dramatically increased summer occupancy to 16-gallon-per-minute showers to pools, hot tubs and the cleaning of recreational boats on peoples’ properties — that account for much of the increase in water use.
She also looked at institutional water uses, finding that the Peconic Landing retirement community and a large nursing home were the biggest users of water in town.
“Caring for the elderly does consume water. We have to look at that industry,” she said, adding that tourism-related industries, including hotels, marinas and food service businesses, also use a great deal of water.
Ms. Berry said the beer and wine production, both major industries in town, are not documented, and data on agricultural use of water is not readily available, in part because most farmers rely on wells that existed prior to water use data collection.
While the state Department of Environmental Conservation and the Water Authority have set a goal of reducing peak demand from 2012 levels by 15 percent by 2020, the CDM Smith report cited by Ms. Berry shows that, for our groundwater recharge to be sustainable, peak use must be reduced by 33 percent.
“The Greenport/East Marion aquifer system should aim for an even higher goal of at least 45 percent, as the water cannot be fully sourced locally, and 100 percent of water use in the sewer district is lost, discharging directly to the LI Sound,” said Ms. Berry in her report. “Future growth needs to be reconsidered, as projected figures for 2030 have already been exceeded.”
Ms. Berry said it costs $600,000 to install one new public drinking water well, money that could go a long way when applied to conservation efforts.
She recommended a major public education program encouraging homeowners to use rain gardens, native plants, smart censors for irrigation and water-wise plumbing fixtures, and urged the town to upgrade to low-volume water fixtures at public facilities like schools, firehouses and community centers.
She also recommended incentives or requirements for people with private wells to install meters to measure and pay for their water use, and that the Suffolk County Water Authority develop a tiered pricing pattern so that heavy water users will pay more for their water use.
“Ultimately a series of planning strategies and regulation may be needed to curb excessive water use,” according to Ms. Berry’s report. “Regulations controlling water consumption for irrigation, swimming pools, geothermal systems, and plumbing fixtures may be necessary and cost effective. Southold needs a zero-sum strategy when addressing water consumption from new development, expansions, or intensifications of use.”
The full Peconic Green Growth report is online at peconicgreengrowth.org/resources/water-conservation-in-town-of-southold.