Chad Anderson and John Sandberg slosh through a muddy stream in hip waders, pausing occasionally to duck under overgrown branches or swat a mosquito.
Sandberg carries a long pole with a metal ring on the end. He moves it through the water, sending out an electrical current that temporarily stuns the fish. Anderson comes behind him with a net, scooping them up.
"We want to capture every single species, every fish," Anderson said. "The little species are sometimes just as important as the big ones."
The team of biologists from the Minnesota Pollution Control Agency is studying the fish to get a better picture of the health of this stream called Whitely Creek just east of Brainerd, Minn., which flows directly into the Mississippi River.
This slow and sometimes painstaking work is part of the MPCA's effort to document and monitor all 80 of Minnesota's major watersheds. The work has produced a wealth of data about the health of Minnesota's rivers, lakes and streams.
"We're essentially sampling these streams, seeing whether they support a fishable aquatic life community," Anderson said. "A lot of streams we sample, nobody's ever been to before."
Anderson says they are starting to revisit places they first tested a decade earlier.
"It's kind of fun pulling up to a stream and it's like, 'Oh, we were here 10 years ago,'" he said. "You hope it looks better than it did when we were there in 2008, not worse."
On shore, Anderson and Sandberg sort the fish they've collected, each species in a separate bucket. At the end, they have a dozen types of fish, a good sign.
"You tend to see greater diversity in the higher quality streams," Sandberg said. "When the streams get really degraded, the more sensitive species start to disappear. So in the really heavily degraded streams, you might just see one or two or three species."
The biologists could just take a water sample, but Anderson says that wouldn't tell the whole story.
"These fish live in the stream, so they're continuously being affected by what's happening around them," he said. "There could be land use changes. They could clear cut something. The habitat in the stream gets degraded. You wouldn't see that in the water sample, but we're going to see the fish community change."
Watersheds are networks of interconnected streams, lakes, ditches and wetlands that eventually flow into major rivers. Even small streams play an important role, Anderson said.
"A lot of people don't think about people downstream," he said. "They think about what's going on on their land, but not how they're affecting everybody else downstream. All this water flows into the Mississippi, which flows into the Gulf, so it just keeps going."
Water monitoring efforts got a major boost in 2008 when Minnesota voters approved the Clean Water, Land and Legacy Amendment.
That led to a "wholesale change" in the scope of what the agency was able to do, said Rebecca Flood, assistant commissioner for water policy at the MPCA. The MPCA gets about $7 million a year for monitoring through the Clean Water Fund.
"We have a lot of water," Flood said. "So it was hugely important for us to develop this systematic approach to figure out baseline where are we now, so we could figure out with our local partners where do we want to go? What are the goals? What are the standards that we need to hit, and what are our plans to get there?"
Water sampling for clarity and pollutants like nitrogen, phosphorus and sediment is collected annually in every watershed. Intensive monitoring is done on a rotating basis throughout the state — about eight to 10 every year.
Once the MPCA finishes compiling the data, it issues a report on whether the watershed is mostly healthy and should be protected, or whether it's impaired with pollution and needs to be cleaned up.
Then it's up to local agencies like soil and water conservation districts to fix problems like eroding streambanks or runoff from farm fields. The data helps those agencies target their efforts, said Steve Woods, executive director of the Freshwater Society.
"What the state has been able to do is come in and say, 'Here's a bunch more information that helps you prioritize your efforts a little better than you can do just by gut feel alone,'" Woods said.
Most states are flying blind when it comes to having data to manage their water resources, Woods said.
"Minnesota is kind of in those top tier of states that actually have that data," he said.
The results of the monitoring efforts haven't been very surprising, Woods said. Water quality in the northern part of the state is fairly good, he said, while many lakes and rivers in southern Minnesota are listed as impaired because of pollution.
"As you go from northeast Minnesota say toward southwest Minnesota, you've got a lot more disturbance of the landscape and a lot more water quality degradation going on," Woods said.
Gov. Mark Dayton has scheduled a series of town hall meetings on water quality in upcoming months as part of his proposed goal to improve water quality 25 percent statewide by 2025. The first one is July 31 in Rochester.