Hydrologists from the U.S. Geological Survey have fanned out across central and eastern Suffolk County in recent weeks, measuring water levels in groundwater wells and at lakes, ponds and streams to document possible drought conditions.
The Peconic River, they found, is seeing some of its lowest water levels since a stream gauge was installed in 1942.
Levels in the Carmans River in Yaphank are well below normal and hark back to a severe drought that occurred in the 1960s. Lake Ronkonkoma and Ridge’s Lake Panamoka also are low.
“This is all to get an overall picture of what’s happening,” hydrologist Amy Simonson said Thursday as she checked levels at a Peconic River gauge.
After collecting the data from about 270 stations, USGS hydrologists will compare it with other seasons, both those with droughts and those considered wet years, said Ron Busciolano, a supervisory hydrologist at the USGS Water Science Center in Coram.
The previous two years were dry as well, he said, and are expected to continue to affect levels.
Heavy rains that hit Long Island last weekend, in the midst of the data collection, “has at least brought us out of any kind of drought in Suffolk County,” said Faye Morrone, a meteorologist with the National Weather Service in Upton. The storm dropped more than 4 inches on Oct. 29 alone.
However, last week and three months ago, Suffolk was classified as abnormally dry by the United States Drought Monitor, a weekly assessment by the U.S. Department of Agriculture of dryness across the country. At the beginning of the year, all of Long Island was in moderate to severe drought, according to the monitor.
“Before the storms, we had half as much flow as usual,” Simonson said. “Eventually it’s going to go back to low.”
Dennis Strunk, president of the Lake Panamoka Civic Association in Ridge, noted, “Our lake goes up and down on a natural cycle. It’s on a down cycle now.”
Rainfall, groundwater and surface water levels are linked, and low stream and lake numbers also indicate lower levels of groundwater, from which Long Island gets its drinking water.
“All of the water that we get for drinking and that gets into our aquifer system is from precipitation,” Busciolano said.
Precipitation levels this year have been slightly lower. Most of the rain occurred during the growing season, when plants drank it up, or with such intensity that the ground became saturated.
“A lot of that water either ran off or wasn’t able to get into the aquifer because it was growing season,” he said.
Aquifers feed lakes where those water bodies’ depth hits the water table. “As the water table raises and falls it’s going to affect the lake level,” Busciolano said.
The Suffolk County Water Authority, which serves 1.2 million residents and is the largest groundwater supplier in the country, has a five-year agreement with USGS to collect lake and stream data, Chief Executive Jeff Szabo said.
“We think it’s important that they do this type of work,” he said.
Water customers should not be worried about water levels, he said, because most of the water authority’s wells are 100 to 800 feet deep.
Sean Mahar, spokesman for the state Department of Environmental Conservation, said the agency is monitoring the situation.
Potential drought conditions motivated the agency earlier this year to require water districts to file conservation plans aimed at reducing water use by 15 percent during peak months. The agency also may seek similar reductions from other large water users, he said.