by CHRIS ROGERS
Could frac sand mining reduce flash flooding in Stockton and improve water quality in Garvin Brook? They might sound incompatible, but a Twin Cities hydrology consultant has a plan that he says would combine environmental restoration and frac sand extraction.
John Dustman is a hydrogeologist and the president of the St. Paul-based environmental consulting firm Summit Envirosolutions. Earlier this month, he shared his long-term vision for the bluffs south and west of Stockton with the Stockton City Council: carving terraces into the hillsides that, he says, would catch runoff and give it a chance to infiltrate into the ground, reducing flash flooding and improving water quality. The sand removed to create those terraces would be sold as frac sand under Dustman's plan. He described the project as an environmental restoration and flood protection project funded by sand sales.
Stockton was hit hard by flash flooding during the floods of 2007, when a sudden torrent of water swept away residents, homes, vehicles, and roadways. The area is prone to flash floods. Two streams meet in Stockton, Garvin Brook and Stockton Valley Creek. Water from surrounding upland farms flows into steep, narrow valleys to the south and west of Stockton.
Dustman said that one of the reasons the area is prone to flash flooding is because when it rains, large amounts of runoff pour off the uplands and down the steep bluffs. The terraces Dustman hopes to create would catch that runoff before it rushes into the creek. The terraces would be 75 feet wide on average and laid out on a contour. The terraces would be graded with a back slope to retain water and planted with deep-rooted native plants to help draw water down into the soil and the sandstone bedrock. Dustman said the native plantings and the "wet cliff" environment created by the terraces would benefit wildlife, that the slowing of runoff would reduce flash flooding, and that increased infiltration would improve the water quality in Garvin Brook and Stockton Valley Creek.
Under his plan, the cost of achieving all of those environmental benefits would be funded by selling the sand mined to create the terraces. "I can see a lot of environmental benefit coming out of what a lot people see as a very evil, threatening industry," Dustman said. When asked whether the project was really meant as a flood control project — not a mining project — Dustman responded, "I think the data collected from the demonstration project will answer that question. If there is no benefit, it would be a mining project. If there is a benefit to flood protection, then it is a flood protection project funded by the value of the commodity."
"It's less about sand I think," said Stockton Mayor David Johannes. "The sand helps fund the science."
In the long term, Dustman's vision would pair a system of terraces on the bluffs upriver of Stockton with wetland creation in the creek bottoms. In the short term, Dustman wants to complete a small demonstration project and measure whether the project achieved its goals. The demonstration project would involve carving an approximately 100-yard-wide terrace on a small side valley and monitoring the quantity and quality of water that flows through the valley. Monitoring a demonstration project could take years. Dustman said his company already has the expensive monitoring equipment necessary to prove whether his idea works.
"If we can quantify the amount of water we are taking out of a flooding situation then at least we would know whether this idea has any merit at all," Dustman said. He added that he is interested in working with the Minnesota Department of Natural Resources (DNR), Winona County, local trout organizations, and other groups to further explore and test out the idea.
Humans have been cutting terraces into North American hillsides for decades to create roadways, but as far as Dustman, local experts, and state officials know, no one has ever proposed building a terrace as a flood protection and environmental improvement project.
Dustman has not formally proposed a project. He appeared before the Stockton City Council to tell them about his idea and to solicit landowners who would be willing to host a demonstration site.
Most of the areas Dustman would consider as terrace sites are outside of the city limits of Stockton, and a demonstration project there would likely require permits from Winona County, possibly including a conditional use permit (CUP) for frac sand mining. If the site were within the city limits, the city would be responsible for any local regulation of mining and bluff land development. There are also a few state permits the project might require, potentially including permits for public works projects that affect public waters and a permit for frac sand mines within a mile of a trout stream — Garvin Brook is a trout stream.
Would Dustman's terraces do all of the things he says they would do? State officials wanted to see more details before they would comment on that question. On the details, "To control flooding by inducing added infiltration, I'm not sure that's going to happen without seeing a formal proposal," said DNR hydrologist Scot Johnson. "It's hard to know what to say when something has never been done before and there's no formal proposal to study," he added.
"It's one of those questions that's very difficult to answer … it really depends," said DNR hydrologist Jeff Green. "Is putting in terraces an accepted conservation practice? Yes, but to do that on a hill slope into the sandstone, that's a different application that I don't think anybody's ever done," he added.
"What you're telling me raises a lot of flags," said Winona State University Geoscience Department Chairman Toby Dogwiler when asked about the terrace idea. "Anytime you're making a major disturbance to the landscape, major disturbances sometimes have many unintended consequences." He added, "I would want to know about it before I passed an opinion on it, but I would take some convincing."
For Dustman, the concept is the culmination of many aspects of his life. He started his career designing "road cuts" on Highway 61 along the North Shore of Lake Superior, many of which were terraces in steep slopes. He went on to study the hydrogeology of the Jordan Sandstone layer, especially Twin Cities aquifers. Because of his familiarity with Jordan Sandstone, Dustman was a sought-after consultant as the frac sand industry emerged. All the while he has been hunting and fishing in Southeast Minnesota and driving past the crumbling outcrop of perfectly formed sand next to Highway 14 near Farmers Park southwest of Stockton. "It was the perfect storm," he said. Now he cannot stop thinking about the idea.
Summit Envirosolutions helps various companies follow environmental regulations and conducts hydrological studies for wells and mines, among other services. The company has worked for frac sand mining companies, and is currently working to prepare the Environmental Impact Statement (EIS) for a number of small sand mines in Western Winona County proposed by Minnesota Sands. Dustman said that the terrace idea is his personal idea, not the company's, but that the company might be involved in providing equipment for the demonstration project.
Interested land owners may contact Dustman via email at email@example.com.
Keep reading the Winona Post for more on this story.