DANVERS — The Ipswich River's flow is at a historic low, but officials say it's too soon to institute watering restrictions.
For this time of year, the river is at its lowest flow rate in 80 years as measured at the Willowdale Dam on the border of Ipswich and Hamilton. The river is also at its lowest flow in 71 years at the South Middleton gauge.
It's no wonder that Town Manager Wayne Marquis told selectmen recently: "It would be nice if it would rain."
While Danvers — which supplies water to both Danvers and Middleton — does not draw directly from the Ipswich River, it draws from the river's watershed. The towns' main reservoir is Middleton Pond on Lake Street in Middleton. The pond is 87.8 percent full, which represents 618 million gallons, so there is no concern about supply yet.
However, when the Ipswich River's flow drops, the amount of water the town can withdraw is curtailed, under a modified water withdrawal permit the towns hammered out with the state Department of Environmental Protection in 2006.
For example, when the river's flow drops below 18.7 cubic feet per second in Middleton, Danvers must stop withdrawing water from certain wells. The town stopped pumping from two wells on Andover Street on Monday, Marquis said.
While it's too soon for water bans to kick in — these start after April 30 — Marquis said officials are monitoring the river level closely. He goes online nearly every day to check the levels, which he described as "far below normal."
The forecast for the next few days shows only a chance of showers, according to the National Weather Service. Since Jan. 1, there has been about 5 inches of precipitation in the Boston area. The normal value is a little more than 12 inches. The region had 9 inches of snow this winter. The normal amount is nearly 43 inches.
Without significant rainfall, the river could be in trouble in the summer when hot, dry conditions and increased demand from those watering lawns take their toll on river levels.
"It means if we don't get rain between now and the natural low period, we are going to be in trouble," said Brian Kelder, the restoration program manager for the Ipswich River Watershed Association.
Yesterday, the U.S. Geological Survey gauge downstream from the Willowdale Dam measured the stream flow at 61 cubic feet per second. It's the lowest flow ever in the 80 years it has been measured at this spot on April 10. The average for this date is usually 484 cubic feet per second. The prior minimum at this gauge was 106 cubic feet per second in 1965.
Yesterday, the river appeared low at the Willowdale gauge site, with portions of the riverbed exposed.
At the South Middleton gauge, the river was running at 12 cubic feet per second, while the median for April 10 is usually 135. The prior low of 37 cubic feet per second on April 10 was recorded in 1965.
As of Monday, Middleton Pond was at 87.8 percent capacity, and water officials were replenishing this source by pumping from Emerson Brook, said Bob Lee, director of operations for the Department of Public Works.
The town has been pumping about 3.4 million gallons a day into the pond. Without any rain, Emerson Brook will drop to the point that the town can no longer use its large pump. It will have to resort to a pump that can put out only 1.1 million gallons, not enough to replenish the pond.
While the pond is certainly more than half-full and nearly at capacity, Lee said: "The first week in April, you would like to have it at capacity."
Marquis told selectmen that if the dry spell continues, it could trigger tighter-than-usual watering restrictions come May 1. So-called Level 2 watering restrictions forbid outdoor watering between 8 a.m. and 7 p.m. from May 1 through Sept. 30.
Marquis asked that residents conserve water now in case the dry weather continues.
"We are keeping an eye on the river," said Salem and Beverly Water Supply Board Superintendent Thomas Knowlton.
Right now, the supply board's reservoirs are full. During the summer months, Beverly's and Salem's water comes only from reservoirs, and Knowlton said it's too early to be overly concerned about the river flow.
"There's always a good chance for a good rainstorm," Knowlton said.
Staff writer Ethan Forman can be reached at 978-338-2673, by email at email@example.com or on Twitter @DanverSalemNews.