Groundwater levels are down on Shelter Island Island as thirstiest and driest season looms

At a time of year when Shelter Island’s underground reservoir of fresh water is usually at its peak, many monitoring wells are showing a significant drop in groundwater levels compared to the levels of March, 2011.

“Usually we’ve had a lot of rain” by this time in the spring, Supervisor Jim Dougherty said as he reported on the issue at the Town Board’s work session on Tuesday, “and the bucket is full. But the bucket is perhaps half full” with the usually drier summer season looming.

He said March 2012 was one of the warmest and driest months of March on record.

Mr. Dougherty said the matter had been raised Monday night by the town’s Water Advisory Committee, when the committee heard a report that water levels in almost all monitoring wells were down as much as 27 percent compared to the levels recorded at the same time last year.

The supervisor said the committee members seemed to feel there was no immediate need to call for public measures to conserve water. But if there are no April showers, the WAC “might have a recommendation after their April or May meeting,” Mr. Dougherty said.

Shelter Island has a small, isolated aquifer that is subject to saltwater intrusion in shoreline areas during times of drought. About a decade ago, the last time the Island endured drought conditions, the Town Board enacted a ban on automatic irrigation systems that rely on groundwater instead of a cistern; that law takes effect next year. The board also imposed water restrictions, limiting the washing of cars and the use of hoses to water lawns and gardens.