NASHUA — The city’s two hydroelectric facilities on the Nashua River have garnered significant revenue because of frequent rain.

“We have actually made a lot more money than anticipated,” Sarah Marchant, community development director, said of the city’s two dams.

There is currently about $310,000 in unanticipated revenue from the hydroelectric operations at Jackson Mills and Mine Falls Park, according to Marchant.

The city typically budgets revenue for the dams based on an average rainfall for 10 years.

“It has been incredibly wet,” Marchant said of the past year, adding last summer was one of the wettest summers on record for the Gate City.

By the end of the year, she estimates that more than $500,000 in unanticipated revenue will be collected from the hydroelectric plants.

Mayor Jim Donchess is proposing that $200,000 of the extra revenue be placed into the city’s hydropower reserve fund since $219,999 from that account was spent on infrastructure repairs throughout the last year.

If approved by the full Board of Aldermen, the replenished reserve fund — once the $200,000 is added — will equal about $269,000.

“We have 40-year-old dams that generally have useful lives of 25 to 30 years, so things are breaking,” acknowledged Marchant, stressing the need for a healthy reserve fund since large equipment is costly if it fails.

In light of the unanticipated revenue, however, the city now owes the operator of the hydroelectric facilities additional funds.

“As the city’s revenue from hydroelectric power generation has exceeded budget to date, additional amounts are due to Essex Power,” states a proposed resolution being supported by an aldermanic panel.

That proposal, if approved by aldermen, would allow $110,000 in extra revenue to be transferred to Essex Power since the city is required to pay the operator a certain percentage of revenue from the dams.

“We are very lucky that the rain has been so efficient, but it has caused us to under-budget our expenses,” Marchant explained to the aldermanic Budget Review Committee last week.

The Jackson Mills hydroelectric facility was returned to city ownership at the end of a long-term lease in 2014; it is currently operated by Essex Power Services, Inc., which handles the maintenance, operations and administration of the plant.

The city closed on its acquisition of the Mine Falls Park Hydroelectric Facility in 2017 — a purchase that was nearly 30 years in the making. Nashua now owns both of the city’s dams and hydroelectric facilities on the Nashua River.