Preserving the St. Croix: All hands on deck

As the St. Croix River lands on Minnesota's impaired-waters list for the third year in a row, conservationists are ramping up efforts to reverse the flow of harmful sediments in the 7,800-square-mile basin.

"We're going to get to a point where it's going to be much more expensive to protect the St. Croix," Jay Riggs, a member of Conservation St. Croix, said about the growing urgency to protect the most popular water destination in the east metro area.

Conversations with "stakeholders" will begin in June, with public open houses to follow, in advance of a fall release of the latest water quality study.

Conservationists are not optimistic that the study will show much improvement, considering the St. Croix's decline began in the 1950s and grew worse over ensuing decades. The good news is that more people than ever are trying to protect the river, said Denise Leezer of the Minnesota Pollution Control Agency (MPCA).

"It's a valuable resource, one that people want to continue to swim in, fish in, use for all their recreational activities," said Leezer, project manager for the scientific study. City economies up and down the St. Croix depend on the dollars the river brings to marinas, bars, restaurants and shops.

Help for the river hails from several directions, including passage of a Minnesota constitutional amendment to protect water quality, a revival of the St. Croix River Association, growing awareness of the St. Croix nationally, more involvement by recreational users and aggressive work in watershed organizations.

Protection of the St. Croix is a race against time because population in the river basin is expected to swell 39 percent by 2020. Resulting runoff from roofs, driveways, parking lots and other hard surfaces will contribute to phosphorous contamination, which leads to algae blooms in Lake St. Croix -- the deep pool extending from Stillwater south to Prescott, Wis. -- and diminishes the river's appeal for boating, swimming, fishing and other recreational uses.

Lake St. Croix landed on the MPCA's impaired waters list in 2008 after excessive amounts of phosphorous were found. The amount of phosphorous and chlorophyll, two river-troubling substances monitored year-round, tell scientists much about the work that lies ahead.

Phosphorous accumulation in the St. Croix is measured in metric tons, which points out the scale of the problem. To meet a goal of a 20 percent reduction in phosphorous by 2020, Leezer said, phosphorous flowing into the St. Croix must be reduced by 100 metric tons a year from the current 460.

Findings from the state study this fall -- called Total Maximum Daily Load -- will help conservationists draft a plan to attack contamination at its sources, Leezer said.

That won't come easy because the basin has 25 watersheds in Minnesota and Wisconsin and 18 tributaries that flow into the St. Croix.

Population growth presents the river's greatest challenge, Johnson said.

"It's probably been impaired based on current standards since the 1940s."

The St. Croix, however, is better off now than it was even 10 years ago. Phosphorous concentrations show a slight decline year after year, and overall water quality has improved since its worst contamination in the 1970s.

That's because of upgrades in wastewater treatment and agricultural practices, and more diligence by people to keep their river useful and appealing, Johnson said.

"We're not talking about a great onslaught of problems in the St. Croix basin, or one single smoking gun," he said. "We have made some inroads. While things have been improving, they haven't improved enough yet."