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  • HDT Team

Watersheds 101

Minnesota sits atop a triple, continental-scale water divide. As one of the exhibit pieces in We Are Water MN describes it: “This means we are not receiving polluted water from a state with lower environmental standards. But it also means we have a responsibility to keep water clean–for our communities and for other states and nations.”

Natural resource professionals and advocates often talk about watershed management when discussing water conservation. In many ways this makes a lot of sense, but what is a watershed? There are many definitions, but the National Oceanic and Atmospheric Administration defines it this way - “a land area that channels rainfall and snowmelt to creeks, streams, and rivers, and eventually to outflow points such as reservoirs, bays, and the ocean.”

So in defining a watershed, whether by natural boundaries or civic ones, a key building block to understanding how to protect water is created.

Understanding your watershed, and how water moves through it, can connect us to the landscape. Knowing what is upstream from you makes you realize the vulnerability and dependence you have on those upstream who care for the land. And knowing that your actions affect others downstream can create a shared responsibility to protect water resources on your property.

One Watershed One Plan

In Minnesota watershed planning is done through the One Watershed One Plan which replaces County Water Plans. This means plans are established using watershed boundaries over government jurisdictional boundaries. Plans are developed with local citizen stakeholder input through public meetings and review, and are overseen by county Soil and Water District Supervisors and County Commissioners from counties within the watershed.

One Watershed One Plan comprehensive plans for the Pine River and the Driftless regions include the Pine River and Winona/ La Crescent watersheds. Their plans are linked below.

Pine River Watershed Comprehensive Management Plan

Winona/ La Crescent Comprehensive Watershed Management Plan

From a conservation perspective, managing watersheds makes sense because they are connected: what happens on the land and water upstream will affect others downstream. And watersheds are scalable, from large major river watersheds, like the Mississippi or Colorado, to smaller subwatersheds, like the South Fork of the Pine River. This allows for grassroots level watershed based efforts, all the way up to large scale planning at the state or national level.

Exits Become Tricky

But that’s where the simplicity of watersheds ends. All water that falls on a given watershed does not exit at the “outflow point” identified in the NOAA definition. Some water will be taken up in vegetation and released through evapotranspiration to the atmosphere. More yet will simply evaporate from surface water and exposed soil, and some will infiltrate into the soil.

Water that infiltrates into the soil often travels horizontally down slope within the soil profile, suspended by restricting layers of fine clay and silt that have filtered down over millennia to collect and form an impermeable layer. Soil scientists typically classify only the first 80” of soil below the surface. These soils are classified by taxonomic order, just like plants and animals. Information on soils for your region can be found at the Web Soil Survey. This is the area of earth that is affected by plant growth, and where water that is available for plant growth is stored. It’s also the water that can be purified by plants as it travels through the soil profile, one of the most important functions of deep rooted riparian buffers.

When Water Becomes Groundwater

The water in the soil profile, from ground level to 80” down, that isn’t used by plants can resurface to wetlands, streams, rivers, or lakes, or it can infiltrate deeper, where it becomes groundwater. Once water becomes groundwater, all the watershed rules are gone. Groundwater can flow to and from neighboring watersheds unimpeded by topography and slope. Influenced largely by geology, how groundwater moves and where it is stored in aquifers is mapped through a geologic atlas, such as this one for Cass County.

The US Clean Water Act was established in 1972 due to several large human caused environmental disasters; a large oil spill off the California coast, the burning of the polluted Cuyahoga River in Ohio, and a soybean oil spill in Minneapolis that entered the Mississippi River and caused an oil slick killing thousands of migratory waterfowl in Lake Pepin. The Clean Water Act was successful in reducing “end of pipe”, or point source pollution from factories, feedlots, and sewage treatment facilities.

What’s been less successful has been the Clean Water Act's efforts to reduce non point source pollution. Often referred to as death from a thousand cuts, non point source pollution comes from small impacts across a broad landscape, most often accelerating how fast water is shed from the landscape. Runoff from development, drained wetlands and degraded agricultural soils are all non point source pollution sources that alter hydrology and move water off the landscape. This runoff carries excess nutrients and pollution downstream, increasing streambank erosion and causing greater fluctuation in lake and river levels. From a water quality standpoint, the last thing we want in a watershed is to shed water.

Solutions and Actions

Small impacts require small solutions that everyone can take. By observing runoff patterns on your land, you can capture runoff in rain gardens and swales. If planted to deep rooted native vegetation, these areas can hold runoff allowing it to infiltrate into the soil and be filtered by soil and plant roots. Improving soil health, either in your yard or at the farm scale, increases the ability of soil to infiltrate and store water, holding it on the landscape to be used by plants and crops, or to recharge groundwater levels. Holding water high on the landscape is imperative to protecting water quality and quantity,

To learn more about your watershed visit the One Watershed One Plan webpage and get involved.

And, if you’re in the Pine River area, stop by the HUG Campus through June 17 to tour the We Are Water MN exhibit, which includes this beautiful map of the Pine River Watershed. Get more information here.

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