DES: Acid Rain is Declining, But N.H.'s Lakes and Ponds Slow to Recover

Jul 31, 2015

When Ted Diers, the watershed bureau administrator with DES, first started working at New Hampshire Department of Environmental Services a few years ago, he spotted an employee walking down the hall with a bucket.

Diers asked him where the bucket was headed and learned that since 1972 employees had been sampling rainwater on the roof of the building for its acidity and for various pollutants.

“And so I said, ‘Wow, that’s a great data set. What do we do with it?’” Diers recalls, “and he said, ‘Well, really nothing.’”

Today, that data – combined with water sampling done at remote, mountain ponds done in partnership with New Hampshire Fish and Game, as well as sampling of low-elevation lakes – has been released in a study from the DES.

That report shows acid rain has declined dramatically since the phasing in of programs to limit the pollutants that cause acid rain, which started in 1990. However, recovery for New Hampshire’s lakes is coming much more slowly.

But Diers says the natural chemistry of the Granite State’s bed-rock makes it difficult our water-bodies to bounce back.

“So while we’re seeing the pH definitely improving in the rain water, it’s going to take a while and it hasn’t quite happened yet to see that pH improve in the ponds,” says Diers.

However, the study does show that in three of the ten high elevation ponds monitored acidity is improving.

Diers says the variation is “because there’s different geology, there’s different sized watersheds, there’s different kinds of plants, there’s different other human activities in the watershed.” He’s hopeful that the more rapid improvement in a few ponds might portend what’s coming for the rest of the state years down the road.