For the first time, Minnesota will study the health of the state's entire stretch of the Mississippi River, from its headwaters near Bemidji to the bluff country where it enters Iowa.

The Minnesota Pollution Control Agency announced Monday that it will send teams to more than 50 sites on the Mississippi. The sampling will take five months and end in September, and marks the first time the state will assess the whole of Minnesota's 650-mile stretch of the river in a single year.

That quick turnaround will give the state a better understanding of the quality of water in the Mississippi, said Katrina Kessler, commissioner of the agency.

Kessler spoke as the wind whipped through budding oak trees on the shore of the river at Hidden Falls Regional Park in St. Paul. She dipped a jar into the river, and pulled out what will be the first water sample of the effort. "The data collected will help direct resources for decades to come," she said.

The state has typically studied the Mississippi piecemeal, taking water quality and aquatic life samples along a few stretches of the river each year. It has taken the state about 10 years to get to the entire river, causing some segments to be studied under vastly different conditions than others.

Over the last 10 years alone, Minnesota has swung from floods and record rains and snowfall to extreme drought and back. Changing water levels change the speed and force of the river, the concentrations of pollutants and the amount of manure, pesticides and erosion it carries.

Measuring the river over one spring and summer will provide a deeper understanding of where things stand, Kessler said.

"It will allows us to say under this type of flow condition what can we see in terms of aquatic life, chemistry, temperature, and what kinds of inputs are we getting from agricultural landscapes, urban landscapes, and industrial inputs, wastewater inputs and storm-water inputs," she said. "Measuring all those things over the course of one season shows us, at this moment of time, where have we come and where do we need to go."

The study will also mark the first time the state takes a comprehensive look at concentrations of PFAS in the river. Agency leaders couldn't say exactly how much the project will cost. The Pollution Control Agency receives about $9 million a year from the state's Clean Water Fund to monitor rivers and lakes and it will be funded with those dollars.

Much of the Mississippi River has been on the state's impaired waters list for years, which typically happens when nutrients, chemicals, bacteria, toxic metals or other pollutants kill off too many fish and insects or make the water unsafe to swim or fish. Excessive nutrients, largely from crop fields and manure, have been one of the Mississippi's most persistent problems, pouring into the river for decades from Minnesota and other northern states and causing a massive dead zone where the river empties in the Gulf of Mexico.