Now that the dust has settled on an action-packed outdoor season in the world of local journalism, it’s time to circle back and report one last amazing thing from the summer past. That amazing thing was a tour of the Coon Creek Watershed with eminent researcher Dr. Stanley Trimble.
On September 7, Trimble who travelled here to participate in the ‘90th Anniversary Celebration of the Coon Creek Watershed Project,’ took about 30 watershed council members and scientists on a tour of the watershed to illustrate some key aspects of the enormous environmental change that had occurred since the time of European settlement.
“In general, I wanted to portray the immensity of environmental change--both bad and good--and some of the causes and consequences on the tour,” Trimble said. “To that end, I attempted to explain and demonstrate the 11 conclusions I drew from the fourdecades of my team’s work, as documented in my book.”
That book is ‘Historical Agriculture and Soil Erosion in the Upper Mississippi Valley Hill Country.’ In his forward to the book, Andrew Goudie of the University of Oxford observed:
“…this book is in the fine (19th century) tradition of tracing the way in which humans have modified the face of the Earth… (this book) about his study examines the ways in which another of the great landscapes of the USA has been transformed by human activities. It is based on almost four decades of dedicated research and has many of the characteristics of a gripping detective story, based on meticulous forensic investigation.”
The tour kicked off at the gas station in Stoddard, and worked its way north in the valley. The day ended with a ‘brats and beer’ picnic celebration at the Genoa Outlook over the Mississippi River. The menu included sausages donated by Driftless Provisions (prepared by members of the Coon Creek Conservation Club), sauerkraut made specially for the event by Monique Hassman, and salad and sides.
Eleven conclusions
Trimble’s tour was designed to illustrate and support what he described as the 11 conclusions of his 40 years of work studying the Coon Creek Watershed:
1. Seemingly haphazard and random, there is actually a systematic time and space pattern to the physical changes shown in this book, and to the resulting effects on human activity
2. While geography may not be a detriment, it is a powerful context within which people act
3. The destruction in the Coon Creek Watershed, as well as most of the worst soil erosion of the world historical record, was accomplished with very simple technology
4. Climate change did not cause the landscape changes described in this study (1973-2007)
5. While humans were responsible for the environmental degradation of the Hill Country, they were also responsible for the almost miraculous recovery of the region
6.Well-designed governmental programs can help ameliorate environmental problems
7. Good policies and actions sometimes have some bad results
8. Many downstream Lower Valley reaches will continue to have channel and floodplain aggradation (sediment build up) from legacy sediment
9. The study clearly shows the utility of much hydrologic and geomorphologic theory
10. The effect of sedimentation on milldams and reservoirs was much greater than the effect of milldams and reservoirs on sedimentation
11. Significant landscape changes, even those that threaten life and property, may soon be forgotten unless well documented and made known.
Begin at the end
The tour of the watershed began at the end – on a farm located just above Coon Creek’s confluence with the Mississippi River.
“The Zink family farm was my first stop when I began my research in 1973,” Trimble told the group. “Oscar Zink was the first friend I made here.”
Trimble said that Zink had many memories of living on the land in the location that helped to document the changes produced on the landscape after settlement. One memory was being able to drive a full load of hay under the limb of a cottonwood tree on the floodplain. With increasing deposits of sediment from erosion, eventually this was no longer possible for his family.
“When settlers first came to this area, they tended to settle near springs for a source of good water,” Trimble pointed out. “By the turn of the century, the Zink’s spring had dried up due to lack of water infiltration on the landscape.”
Not only did the spring dry up due to lack of groundwater recharge, but the family was confronted during storm events with torrents of water, and a frightening freight train of sediment and rock, coming off the hillsides and into their yard and fields. As a result, a huge ‘alluvial’ fan (made up of sand and earth left by rivers, floods) was deposited over the area. Trimble said the Zink family had used the deposited rock to build a diversion around their home to prevent it from being buried.
“What the family experienced in the late 1800s and early 1900s was a tragedy,” Trimble said. “The human pathos of it is hard to comprehend.”
Trimble said that the deposits of sediment and rock actually moved the course of the stream across the valley. He said it was a “huge hydrologic theory brought to life right here.”
But Trimble seemed most amazed by the fact that land use changes adopted since the 1930s had such a big impact in turning things around, despite the uptick in rainfall in the watershed since the 1920s.
“With the increase in conservation measures on the landscape, more water was able to infiltrate to recharge groundwater aquifers and sustain the baseflow of the streams,” Trimble pointed out. “There is still erosion happening, especially in larger storms like we saw in 2007 and 2008, and especially in 2018, but it is greatly reduced.”
Nevertheless, Trimble said that the sediment really isn’t working its way through the watershed and out into the Mississippi River. He said that because of the wide floodplain, the stormwater runoff carrying the sediment is slowed, and most of the sediment doesn’t travel very far before it is deposited.
In his conclusions, after observation of the impacts of the 2007 storm in the watershed, Trimble observed the following:
“…there was a lack of visible erosion off no-till fields [after the 500-year storm in 2007]… and the extreme storm did not destabilize the landscape and take it back to the conditions of the 1930s… the inherent stability of stored sediment and the inability of the storm to move it out of the watershed… relates not only to resistance of the landscape but also to the distribution of forces from such a storm. Recall that during a flood, the flow by definition exceeds the main or low flow channel and uses the flood channel or floodplain. With a wide floodplain… the flow spreads out and loses much of its tractive force to erode…the floodplain is protectedagainst erosion by vegetation…which by slowing the flow induces deposition of sediment transported by the water. Thus, the huge flood may erode the channel and banks, but storage on the floodplain subsumes much or most of this. The result is the process of removing stored sediment from a watershed in humid, vegetated regions is a slow one.”
Trimble reminded the group that most of the sediment in the floodplain was stored in the stream basin in just a few decades. He said that “what we see here suggests that it will take centuries or even millennia for the sediment to be removed.”
“I don’t blame the farmers for any of the historic soil erosion,” Trimble told the group. “They came from a much more temperate climate in Western Europe where they didn’t have thunderstorms like we have here.”
Trimble said the changes on the landscape had come about as the result of government experiments in erosion control, and it took a while for farmers to adopt the ‘crazy quilt’ farming methods, such as contour strip cropping, terraces, and more.
“It was a generational thing,” Trimble said. “It really wasn’t until the 1940s and 1950s that the true impacts of the changes made on the landscape began to be felt.”
Next stops
The next two stops on the tour included a railroad embankment that had been built in 1904, and a pond that had formed when another railroad embankment caused sediment to build up and form a ‘sediment shelter.’
“The sediment that has built up behind the railroad embankment built in 1904 provides a good estimate of accumulation of sediment on the floodplain by that time,” Trimble said. “With the massive debris flows that occurred in the late 1800s and early 1900s, any manmade structure such as roads, bridges or railroad embankments served to trap sediment and prevent it from moving down the watershed. There are countless such structures in the floodplain that are completely buried.”
The fifth stop on the tour was at the confluence of Wing Hollow and Coon Creek. At that location, at the coming together of the two streams, the historical sediment deposited had built out onto the Coon Creek floodplain, forcing Coon Creek’s channel to move about 200 feet to the north.
“The differential deposition of sediment in the watershed, creating sediment sinks, is resulting in the backwater areas becoming larger, wetter and deeper,” Trimble explained. “In the 1930s, we were seeing as much as six-inches per year of sediment accretion in the floodplain, most of it between 1900-1950, and it is not moving out anything like as quickly as it was deposited.”
Trimble said that soil borings taken in the floodplain over the course of the 40 years of his work there have confirmed the rates of sediment deposition. At the sixth stop on the tour, Trimble showed where an old metal bridge had been buried in sediment in the floodplain. He said it had been necessary for his team to dig down and identify its location because it was one of the landmarks that the old surveys had been based on. In addition, sediment had buried a road and the railroad embankment at the location.
“Streams tend to build channels big enough to suit themselves,” Trimble said. “For instance, the channel fairly quickly resumed its pre-flood size after the 2007 flood because it became a sediment sink. What this means is that sediment being displaced in a big flood isn’t being carried out of the watershed – it is simply being redistributed, and if holes are created in the flood, eventually they will fill back up.”
Story of Chaseburg
Trimble spent a lot of time talking with the group about his beloved Chaseburg, where he and his students had spent many days. He fondly lamented the demise of one of the final businesses to survive in Lower Chaseburg – the Hideaway. He pointed out where in the now empty space the Gardner Garage, the Martiny house, the old mill, and a fine ‘Italianate’ hotel used to be located.
“At the intersection in this empty space used to be the central business district of old Chaseburg,” Trimble told the group. “It had an elegant stone bank, a large brick market, a barbershop, an old-fashioned service station, and several taverns, with many residences beyond.”
Trimble said that the bridge had once spanned the old mill pond, with a cheese factory just beyond that. He said that his book contains pictures documenting that the bridge was much closer to the top of the creek after the sedimentation from a flood in 1907 (the first big flood in the area). He pointed out that there had once been two channels of the creek flowing through Chaseburg, and that one of them had been allowed to become plugged up, thus making flooding problems worse.
Proceeding up off the creek bottom and through the new Upper Chaseburg, one can see how the town was forced to retreat up the hillside. Moving north through the valley, Trimble explained that the reach of the stream between Chaseburg and Coon Valley contains several buried bridges. He said that Highway 162 had to be raised several times over the years to accomodate the increasing size and depth of the wetlands.
Coon Valley
Trimble pointed out that the village of Coon Valley had come close to destruction in the 1930s and 1940s, but had been saved by a forced channel enlargement. He said that eventually, soil conservation measures implemented on the landscape had pulled the village back from the brink of peril.
The group paused for lunch in Coon Valley, and enjoyed a chance to get out of the car, stretch, and talk with other tour participants.
Genoa Outlook
After eating dinner, Dr. Stanley Trimble was to have given a talk, accompanied by a power point presentation. As luck would have it, the computer available could not accommodate the CD he’d brought his presentation on, so he spoke to the group extemporaneously.
“It has been 50 years and three months since I first came here to investigate what happened in the Coon Creek Watershed,” Trimble said. “We now have almost 100 years of soil conservation measures on the landscape under our belts – what has it accomplished?”
Trimble said that the effects of soil erosion in the Coon Creek Watershed had first been studied by a scientist named Stanford Happ in the 1930s. Trimble’s work picked up where Happ’s had ended, and expanded it.
Trimble said that in the United States, agriculture had really started in the south, but had moved north in order to take advantage of superior soils. As a result, he said, most of the land in the east is now forested.
According to Trimble, those early farmers had originally been ‘old Americans,’ but were eventually replaced by Germans and Scandinavians. He said those people had been used to a much more temperate climate where they came from in Western Europe. Here, they encountered a harsher climate with big, violent thunderstorms.
“The early immigrants thought that the soils here were inexhaustible, but they lost their infiltration capacity and resistance to erosion by about the late 1800s,” Trimble explained. “The landscape came apart after about 40 years of farming, with soil eroding and deposits of about six inches per year in the valley. This was bad trouble for the impacted communities.”
Trimble said that in all, there were 30 or more bridges in the watershed that had been buried by sediment in those years. He said that these conditions had made life very tough for the people who lived here, and they wondered what they could do about it.
“It was the Soil Erosion Service (SES) to the rescue in 1933, which became the Soil Conservation Service (SCS) in 1935, and eventually evolved into today’s Natural Resources Conservation Service (NRCS),” Trimble said. “Ag professionals had been pondering the problems like those in Coon Creek that were plaguing communities, and had come up with the technology to conserve soil – they just had to figure out how to reach local citizens with the message.”
Trimble said that from this challenge had arisen the idea of conducting a demonstration project to show people how to conserve soil, and that led to the Coon Creek Watershed Project 90 years ago.
“Part of the problem was that the Europeans were used to a three-field rotation, when what they needed was a five-six-seven year rotation, with more time in grass,” Trimble explained. “In the Coon Creek Watershed, the SCS helped farmers to survey and place contour strips, and they began to be able to show other farmers the results to convince them to consider adoption of the practices,” Trimble explained. “The soil conservation measures were effective, and by about the 1940s, people really began to be able to see the results.”
But, Trimble said, now we have a new problem – climate change. He said that this has made the storms even bigger, more intense, and more frequent.
“I am not a climate change catastrophist, but there is no denying the storms are getting larger,” Trimble said. “The 2018 storm blew me away, when the railroad tracks in Stoddard were overtopped – I never thought that could happen. These storms are exceeding anything we have seen before, and exceeding our ability to deal with it at the current time. I don’t know how this story will end.”
