Record or near-record-high ground water levels are occurring across many parts of Long Island, N.Y., as a result of frequent and intense precipitation during the past several months. Record-high ground water will continue for weeks to come, according to the U.S. Geological Survey (USGS).

The high water-table has caused widespread flooding of basements in parts of southwestern Nassau County and in central Suffolk County. Water-level records from wells in these areas show long-term upward trends that have reached record or near-record highs. More sporadic flooding has been reported in some locations near-shore and near stream channels throughout Long Island.  

“Since October 2005, Long Island has had more frequent and intense precipitation events, keeping ground water levels above normal,” says USGS hydrologist Ronald Busciolano. “The record precipitation, along with long-term water-management practices such as the installation of stormwater-retention basins and reductions in ground water withdrawals in western parts of the island, have amplified ground water-flooding problems in some areas.”

In the coming weeks, the USGS will conduct an Island-wide assessment of current ground water conditions to better quantify the high water-table and produce an updated depth-to-water map. More than 600 wells across Long Island will be measured. This monitoring program is supported by funding from numerous federal, state and local agencies, including the Nassau County Department of Public Works, New York City Department of Environmental Protection, Suffolk County Department of Health Services, and Suffolk County Water Authority.