This article is part of a larger series that investigates what we know about local tributaries around Lake Pepin. Follow us on Facebook and sign-up for our e-newsletter so you don’t miss the next release. If you have information or pictures for other Lake Pepin tributaries, please email us at: info@lakepepinlegacyalliance.org.
By: Emily Green
Lake Pepin’s longest tributary, Rush River flows for nearly 50 miles from its source near Baldwin, WI, to its mouth at Maiden Rock. Its nearly 185,000-acre watershed, including parts of St. Croix, Pierce, and Pepin counties, dwarfs that of any other Pepin tributary. Wells Creek, the largest on the Minnesota side, drains around 46,000 acres. Collecting water from such a large area, and fed by 12 smaller tributaries of its own, Rush swells to a sizeable river by the time it empties into Lake Pepin.
Substantial upstream groundwater input helps maintain the perennially cold, clear water conditions that make Rush one of Wisconsin’s finest trout streams, well known among anglers regionwide. According to Wisconsin Department of Natural Resources (WDNR) fisheries biologist Kasey Yallaly, Rush’s trout density, estimated at around 8,000 fish per mile in some stretches, puts it on par with prized trout streams nationally. “It’s an amazing river. It's got beautiful valleys and hills and coulees and ridges. And there’s just few other rivers that I know of where [trout] populations are that high,” said Yallaly.
The shared storyline of driftless-area streams
Like all the driftless-area streams, the dramatic bluffs, forested valleys, and steep gradient that make Rush so scenic also make it inherently vulnerable to flooding and erosion. In addition, the clearing of watershed lands for agriculture triggered complex changes that impacted the river’s shape and flow; this effect is still playing out today. For example, removing upland forests and perennial grasses increased and hastened precipitation runoff into Rush and its tributaries. Eroded soil then accumulated in Rush’s lower reaches, resulting in areas of steep and exposed dirt banks, which further exacerbate erosion vulnerability. Degraded water conditions also likely decimated Rush’s native brook trout population during the early- to mid-20th century. But soil conservation practices and restoration efforts have since helped shift the trajectory, and an introduced brown trout community is now thriving in Rush.
Stream bank erosion
Upland land management efforts are key to Rush’s health and quality
While soil conservation efforts have been underway since the 1930s, substantial work over the last two to three decades have been key to stemming the tide of soil erosion, and improving Rush’s water and habitat conditions. The Pierce Co. Land Conservation Department (LCD) has been hard at work encouraging landowners to implement conservation practices such as grass waterways and grade stabilization structures. In 2015, they received roughly $4 million in funding from the USDA’s Mississippi River Basin Initiative (MRBI) to fund cost-sharing for landowner conservation efforts focused on reducing sedimentation, phosphorus, and nitrogen loads in Rush’s middle stretch and nearby Isabelle Creek. Rodney Webb, LCD’s Land Conservation Director, said they’ve used the MRBI dollars especially to help landowners implement no-till planting and use of cover crops, two practices that are well documented to reduce erosion, improve the health of nearby waterways, and reduce downstream nutrient loading.
According to Webb, the cost-share program has been very popular among locals. He estimates about $4 million has been distributed to around 100 landowners, and landowners in other stretches of the Rush quickly began asking when their turn for funding will come. “[No-till and cover cropping] have become very popular in these watersheds,” said Webb. “The long-term hope is that the incentives encourage real change. That once the dollars are gone, [landowners] will continue doing them.” The allocation of funds was completed by the end of 2018, but some of the contracts are up to 10 years in length, so the implementation of funded projects continues.
In Webb’s view, there’s no question that funding incentivizes landowners to try new conservation measures. But they’re also increasingly motivated by seeing the damage, and experiencing the costs, associated with big rain events, which are on the rise due to climate change.
“Townships were having to spend a lot of money and time cleaning out road ditches that were filled in with sediment, and people started seeing that that could be prevented by doing things differently. ”
“When you're farming a field, then you drive by one day and see the construction equipment removing soil from that ditch that absolutely came off your field. That's a motivator that maybe we need to do something different,” he added.
Webb is confident that efforts to increase conservation practices have made a difference in the landscape, and for the Rush River. A historic rain event in June 2020 caused near-record water levels and flash flooding on Rush. While the flooding caused hefty damage and erosion, Webb notes that it could have been far worse. “Without all those efforts in place, I'd be scared to see what the river would have looked like,” Webb declared.
Despite gains, ongoing challenges for Rush
There seems little doubt that investments of effort and conservation funding have positively impacted Rush River. Because of its thriving brown trout population, the WDNR has included Rush on its “Healthy Waters” list, created in 2018 based on assessments of fish and macroinvertebrate populations and phosphorus levels in waterways. Yet while the Rush meets WI standards on those metrics, the WDNR does not routinely monitor its rivers and streams for other measures of health, such as sedimentation. Nor does it measure bacteria, which can be associated with nearby animal agriculture production, and if elevated makes a water body unsafe for human recreation. In the absence of monitoring, there’s no way to track how Rush compares to other rivers in those areas.
Despite being categorized by WI as a “healthy water,” some local people have substantial concerns about threats to Rush and its resilience into the future. Retired engineer and Pierce county resident Carl Nelson took it upon himself to study Rush and its ecosystem in depth, and wrote a 2019 report entitled “The Lower Rush River: Present health and a call to action” [2]. In it, he emphasizes that the current threats to Rush are formidable, including ongoing soil erosion that threatens water quality, and lack of riparian and surrounding grassland habitat with an associated loss of biodiversity tied to the river ecosystem. Both Nelson and LCD’s Rodney Webb stress that while upland soil conservation efforts have been highly valuable, the reality is that much more work would have to be done, at tremendous expense, to thoroughly stabilize all of the vulnerable banks and protect Rush from the more frequent and intense rains that are predicted for SW Wisconsin under climate change. Nelson says he would love to see a citizen group form, to share in the protection and advocacy of a healthy Rush River.
Above all, Webb is encouraged that so many local landowners and natural resource agencies are paying attention and eager to adopt and support conservation practices. “I think we're very fortunate. Here in Pierce County, our conservation staff, we have people that are very dedicated and have lots of years of experience. And we have our federal partners, and agency partners and a lot of partners that really help promote conservation. So all together, hopefully we're gaining ground. Hopefully kids down the line can say, ‘Hey, it's not as bad as we thought it was gonna be.’”
[1] See our blog post on Isabelle Creek for more on how the differing water monitoring and categorization approaches between MN and WI result in superficially contrasting pictures of Lake Pepin tributaries across state lines.