City: please limit water use

Nine months of below-average rainfall create concerns in Portsmouth

Portsmouth has experienced nine consecutive months of below-average precipitation. It’s also the fourth straight year that the city’s rolling average has been below normal.

That’s according to a water supply status report released by the Portsmouth Department of Public Works on Monday. The report indicates that a combination of exceptionally dry conditions, high demand for water, and the loss of the Haven Well have caused the water supply to be lower than normal.

City officials are asking Portsmouth residents to voluntarily limit their use of water for irrigation and other purposes. Residents are asked to be efficient with their water use and refrain from watering their lawns or gardens between the hours of 10 a.m. and 6 p.m.

Brian Goetz, deputy director of public works in Portsmouth, said the city might call for further limitations if conditions do not improve.

“Our water system is currently keeping up with demand,” Goetz said in a press release. “However, if dry conditions persist the Water Division may consider issuing additional restrictions on non-essential water use in the future. They could include odd/even or two-days/week watering schedules.”

The Portsmouth Water Division's Water Supply Status

Key findings from the report include the following:

  • Irrigation demands in the water system are currently at levels normally not seen until July or August. So far in June, average daily water demand has been 5.62 million gallons, which is 550,000 gallons above the 10-year average of 5.07 million gallons in June.
  • Total June precipitation as of June 26 was 1.5 inches, which is 2.17 inches below the historic average for June. Eighty-two percent of this month’s precipitation came from a single storm on June 5.
  • Total precipitation over the last 12 months has been 32.91 inches, which is 15.28 inches below the normal annual average of 48.19 inches.
  • Groundwater levels are considered average for June. This is largely because the city increased its winter and early-spring withdrawal from the Bellamy Reservoir to reserve groundwater supply sources for the summer.
  • The Oyster River’s average stream flow in June was 4.37 cubic feet per second (cfs), which is 11.9 cfs lower than the 30-year average of 16.27 cfs. Average stream flow in the Lamprey River was 53.7 cfs in June, which is 185 cfs lower than the 30-year average of about 239 cfs.
  • The Bellamy Reservoir stopped flowing over the spillway during the last week of May. Typically, this does not happen until late June or early July. The reservoir level is now 3 inches below the spillway.
  • The city’s water supply capability, which is used to identify issues that would limit the amount of water that could be supplied, is currently considered “below normal.” This is partly due to the loss of the Haven Well, which was shut down in May 2014 due to contamination. The Haven Well previously accounted for 10 percent of the Portsmouth Water Supply System’s capability.

While the weather forecast is calling for some rain this week, “it will take a considerable amount of rainfall to make up for the current deficit,” the press release says.

This is the second time this year the city has called for efficient water use. The city issued a similar request on June 2 due to an unusually dry spring season. During the months of April and May, the city got just over 3 inches of combined precipitation, which is about 5 inches below average for those two months.

“Public participation in simple practices such as limiting outdoor water use during the daytime and only watering when necessary will be helpful in alleviating water demands,” Goetz said.

To view the full water supply status report click hereTo find tips regarding water efficiency click here, or go to the Environmental Protection Agency’s website here.