Under the Microscope

Can Minnehaha Creek be restored?

Experts weigh in on problems, suggest solutions


Leaves rustle in a dry creek bed, tiny fish drift ever so slightly in stagnant pools of murky water. Drips slip past and quietly fall over the limestone cliff. While the mighty gush of Minnehaha Falls usually fills the park with the constant roar of a 65 cubic feet per second leaping 53 feet down from the limestone edge on its way to the Mississippi, the drought of 2022 saw a complete standstill to the water flow through the creek. Similar but less severe droughts stopped the creek flow in 2000, 2009, 2012, and 2021, as well. These droughts leave residents worried for the health of the creek and lakes, and they aren’t the only problems facing this highly urbanized watershed.
Minneapolis loves Minnehaha Creek and falls. Traversing the entire city, west to east and culminating in a stunning waterfall, it is the highlight of an important nature corridor and recreational space between lake Minnetonka and the Mississippi River. While drought may temporarily remove this beloved landscape feature, spring melt from this winter’s barrage of snow will soon fill the creek, and once again Minnehaha Falls will roar with thunderous splashing to the delight of visitors and residents alike. Long before President Johnson’s foot prints were enshrined in concrete at the top of the falls, Minnehaha Creek and the bodies of water associated with it were highly productive food sources for local Dakota and other Indigenous Peoples. These vital resources were plundered into near oblivion by White settlers.
Dakota scholar and author, Dr. Waziyatawin, executive director of Makoce Ikikcupi stated, “Settlers rarely recognize the inherent importance of letting natural features be, to exist as they were intended, instead only seeing value in what people have created at the expense of the natural world. Certainly, this is the case at Bde Psin.” (Rice Lake/Bde Psin now called Lake Hiawatha.)
“Since settler occupation, 90 percent of the wetlands in Minnesota have been destroyed. It’s hard to imagine a more destructive culture than that which invaded our beloved homeland.”

How it used to be
Reading historical accounts of the massive productivity of local ecosystems and the way that productivity was attacked and dismantled is to see a glimpse into the devastating reality of colonization that occurred in Minnesota. According to Rich and Susan Cairn, in their report, “History of Minnehaha Creek Watershed,” “When Americans first passed Minnehaha Creek around 1800, they saw unbroken wilderness. In fact, Native Americans had lived here for millennia, growing crops and opening the forest with regular burns. Yet theirs were mostly impermanent changes. By contrast, the first White settlers in the 1850s soon logged and plowed most of the watershed. Wildlife retreated to undeveloped corners. Large animals such as bear and bison disappeared. As farmers drained lakes and wetlands for fields and pastures, runoff increased. Animal wastes and erosion fouled the waters.”
Writing about the early 1900s, author Coates P. Bull, recorded: “Sucker and Redhorse each spring swam from Lake Harriet through the outlet into Minnehaha… Settlers, even from Eden Prairie and miles to the west, brought their spears to harvest bushels of these fish to eat and to feed pigs… Farmers… could, and did, go down with pitch forks and pitch the fish out onto the banks for their fish fry.”
From an article encouraging European emigration in an 1852 Massachusetts paper, “The prairies are small, so that timber and water are easily accessible. And the natural meadows afford an abundance of good hay. A farmer may come on early in the spring, with team and stock enough for a well-cultivated farm. He can readily find a location, where he can plow land and put in his seed… The lands west of the Mississippi river, heretofore belonging to the Sioux Indians, are now open to settlement, and emigrants have been pouring into them like a flood for the last few months… Those who wish to get good farms, and to get them cheap, will do well to come on early in the spring….”
As the creek was being plundered for its ecological riches, the watershed that surrounds and feeds the creek was being permanently changed. According to the report compiled by the Cairns, “Settlers could ‘pre-empt’ or claim 160 acres at a low government price as long as they built and occupied a house, fenced and cultivated land right away. … By 1860 the entire watershed had been claimed, most of the forest had been logged, and most of the prairie plowed.”
As development continued through the 20th century, the watershed has been dramatically altered. According to Minnehaha Creek Watershed District Communications Coordinator Stacy Carlson, “Over the last 100 plus years, the creek’s natural curves have been straightened and ditched, and in places the creek has even been relocated to accommodate land use change. A land survey from the 1850s shows stretches of the creek located up to two blocks north of where it runs today. In addition to the creek being moved, the surrounding land has been changed in a way that fundamentally affects parts of the water cycle. For example, 33% of the Minnehaha Creek subwatershed is covered by impervious surfaces, and Minneapolis has lost about 88% of its wetlands.”

Consider storm-water run-off
Given the massive difference in the way the watershed is managed today, is it possible to recover any glimpse of the historical health and productivity of the creek and watershed in today’s urban environment?
St. Thomas University associate professor of biology and biochemistry, Gaston ‘Chip’ Small, provided context: “One of the big differences between urban watersheds and more natural watersheds is the extent to which we have altered the hydrology, by [constructing] impervious surfaces. In urbanized watersheds, a much larger fraction of rainfall becomes surface runoff, and streams tend to be ‘flashier,’ with large jumps in discharge following rain events. This can scour stream beds and cause erosion of streambanks.”
Professor Small further explained: “Runoff from urban watersheds also typically carries contaminants from roads, lawns, and other land cover – chloride from road salt is a big issue, but also fertilizer, pesticides, herbicides, and other chemicals. For example, leaf decomposition is an important part of nutrient cycling in forests, but leaves from roadside trees that end up in storm sewers represent a significant input of phosphorus in urban lakes. Collectively, these impacts are referred to as ‘urban stream syndrome’ and often lead to a biotic community dominated by pollution-tolerant invertebrates.” When asked whether pollution tolerant invertebrates provide enough nutrition at the right times of year to feed an abundance of native fish and birds, Professor Small stated, “I would guess that, in highly polluted streams dominated by pollution tolerant species, you’re not going to have a lot of strictly insectivorous fish, and maybe more likely to have omnivorous fish species that could adapt to available food resources (or no fish at all). I suspect, too, things like mosquito control in the metro has a big impact on food resources for insectivorous birds and bats.”
Minnehaha Creek Watershed District (MCWD), is the federally funded organization whose watershed wide mission is to: “protect and improve land and water for current and future generations.” Carlson spoke to me about the importance of their work. “Replacing nature’s storage and filters has increased the volume of runoff when it rains, and the pollution delivered to the stream. It has also fragmented and degraded the riparian corridor that used to buffer the creek, reducing wildlife habitat and separating communities from the creek ecosystem.” When asked about MCWD’s work to restore the health of the watershed, Carlson stated, “In the Minnehaha Creek corridor, we have emphasized partnerships to regionally capture and treat stormwater runoff before it is delivered to the stream. We have addressed the physical structure of the creek, its geomorphology, by adding meanders, in-stream woody debris and pools and riffles to mimic a natural system. And we have expanded, restored, and connected the surrounding riparian greenspace for wildlife and people.”
And there is still so much more restoration to be done. When asked what would happen if 100% of the rainwater falling on the watershed were diverted into rain gardens, swales, ditches, and seasonal wetlands, Carlson replied, “Whenever you’re able to stop water from draining straight from an impervious surface to the creek or any water body, there can be significant benefits for the whole ecosystem.” She added, “We always encourage people to take a step back and see their community as part of a larger ecosystem.”

How to fix the creek
Renowned ecologist and New York Times best-selling author, Doug Tallamy, recently weighed in. When asked what we could do to improve the ecological productivity of Minnehaha Creek, Tallamy replied, “Historically these streams want to be shaded. They want to be colder than they are. You cut down the trees, warming the water and right away that cuts out several species of fish including the trout.… We’ve removed woody debris that used to be a function of all of our waterways to make them navigable and prevent ice dams and maybe because we thought it looked ugly, who knows, but that’s where the fish breed.”
Tallamy continued, “Around every stream is a flood plain – it’s supposed to flood. We killed all the beavers which were a function of every aquatic system in this country and, in doing so, we changed the hydrology of the entire country. Now they’re starting to come back, we’ve got to let them do that, allow them to come back. Shading streams, bringing the beavers back, allowing some wood debris in the water, and creating a flood plain around the creeks would boost the productivity tremendously. And, of course, what does the shade got to be from? From native plants, because the primary component of the food for the fish in the streams, isn’t aquatic insects, it’s the insects that fall into the stream from the trees and plants above.… Put all those things back and you will build the fish populations up again.… One report showed 80% of fish insect consumption comes from insects falling out of trees and in the water.
“Within the Minnehaha watershed you’ve lost your infiltration, the deluge of water after a big rainfall speeds up and scours the stream. Storm-water runoff is a major killer of streams. Whereas, a well-buffered forest riparian community will reduce the flow into the creek. It could soak up the rain as a sponge and then slowly release it so you have steady flow through the year instead of this deluge in the spring and then nothing. It’s the same old thing, putting the plants back solves most of the problems.
“You don’t want the influx of nitrogen, phosphorus, and silt into the streams because that degrades them on every level. Seasonal wetlands and rain gardens are your best bet. Minnehaha Creek flowing through the center of Minneapolis is a challenge because its surrounded by concrete. But you have a huge park system in Minneapolis and every one of those acres should be designed for storm-water retention in one way or another.”


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