Darcy Running can see a little more than a foot ahead through the water when he swims near his house. He’s lived on Upper Prior Lake since 1986, and can’t remember anything different.

“There is a lot of algae in the water, and I think that it’s been about the same over the years,” he said. “It doesn’t bother me.”

Upper Prior Lake, Lower Prior Lake and Spring Lake form a chain that’s spent years on the state’s impaired waters list ­— a biennial compilation of bodies of water that don’t meet state water quality standards.

But residents aren’t too worried.

Upper Prior Lake is about to get a new restaurant, which is expected to draw customers from across the south metro. While there’s excitement about the spot — the area’s only lakefront restaurant — it’ll look out onto waters that have been noted for high algae levels that can make the lake unsuitable for swimming and boating.

Upper Prior Lake has been on the impaired waters list since 2002. Water flowing in from Spring Lake is a big part of the problem. Spring Lake been designated as impaired since 1998, largely because of runoff from agriculture and development.

“It’s been many, many years of runoff into these lakes,” said Chris Zadak, watershed project manager at the Minnesota Pollution Control Agency. “So we’re dealing with a lot of legacy pollutant there, too, that’s accumulated on the lake bottom.”

The local watershed district has been taking steps for years to improve water quality in the area, and is trying to prevent runoff into Lower Prior Lake, which is already impaired for mercury in fish. In fall 2013, it started a three-part alum treatment to mitigate phosphorus levels in Spring Lake.

In June, the alum had reduced the amount of phosphorus by more than half. In 2014, phosphorus levels dropped in Upper Prior Lake, too — likely because of the improvement at Spring Lake, said Diane Lynch, Prior Lake-Spring Lake Watershed district administrator.

But the alum stays at the bottom of the lake, she said, and doesn’t reduce what flows in.

“Even though we’ve been able to contain a lot of the phosphorus at the bottom of Spring Lake, there are still sources bringing more phosphorus into the system,” she said.

Lake life continues

Construction of the new restaurant, called Charlie’s on Prior, began in April. It’s expected to open in the fall.

“It’s not like an area around Excelsior where you have multiple restaurants and things on the lake, but it is something of importance the Prior Lake community,” said Dan Rogness, Prior Lake’s community and economic development director.

Resident opposition delayed the project early this year, but at the time some locals countered that they’d like a lakefront restaurant close to home as an alternative to entertainment hubs such as Lake Minnetonka.

But massive Lake Minnetonka, despite some impaired areas, has clear spots designated as suitable for recreation. Upper Prior Lake, which covers a much smaller area, doesn’t have that variation.

Still, residents continue to flock there. Liz Weninger, whose daughter lives on the lake, said her grandson is in the water constantly. “He’s a fish,” she said.

Jeff Petschl, a partner in the restaurant group that’s opening Charlie’s on Prior, lives on the lake, too. He said he thinks customers will be drawn more by the restaurant’s offerings than by the water it overlooks. And though he wishes the lake looked better, he said, he doesn’t have any concerns about water quality and safety.

“I have two young kids,” he said. “I’ll bet they’re in the water right now.”