Posted on June 23, 2020
The work is contingent upon the city removing more trees and approval of Pipestone County Commissioners
Pipestone County’s Ditch Committee voted on Monday, June 8 to dredge the county ditch from the Ninth Street NE bridge near the campground to the bridge on North Hiawatha Avenue.
The vote is a step toward what Pipestone County said last fall that it would do in response to a request from residents in northeast Pipestone for some type of action to prevent flooding of that part of town. The plan as of last fall was for the city to remove trees along the ditch over the winter and the ditch committee to proceed with dredging the area in the spring and summer.
Ditch Committee Chair John Shaffer said the project is contingent upon the city removing about 60 more trees that are within the ditch right-of-way, which is 16.5 feet from the banks, in the project area and county approval because the ditch committee is under the authority of the Pipestone County Board. Pipestone County Administrator Steve Ewing said the county board will consider approving the ditch committee’s plan during its June 23 meeting.
The ditch committee would also like to dredge a portion of the ditch east of Winnewissa Falls on Pipestone National Monument land. Shaffer said the company the committee has contacted to dredge the ditch said the project won’t accomplish much if that portion of the ditch isn’t dredged.
Shaffer said committee members met with city of Pipestone officials last week about the trees and with Pipestone National Monument staff about accessing the federal land.
City Administrator Jeff Jones said the city’s public works crew removed trees north of the bridge on Ninth Street NE earlier this year. He said he plans to review the information from the ditch committee with Public Works Director Mike Bloemendaal and then discuss it with the city council.
Shaffer said the Monument staff was looking into whether dredging could be done on their land and that Pipestone County Attorney Damain Sandy was also looking into the matter.
Monument Superintendent Lauren Blacik said the Monument is concerned about persistent flooding and has been communicating with community partners about “science-based solutions, recognizing that most flooding effects result from development actions outside the park.”
“We are seeking to better understand how dredging on Monument property would affect storm flows and whether it would alleviate flooding issues,” Blacik said.
She said the answer to that and whether the county has legal authority to dredge the ditch on federal land will determine the permitting process if the county or ditch committee pursue dredging there.
Pipestone County Commissioner Luke Johnson, who also sits on the ditch committee, said the committee has been in contact with Johnson Ditching out of Lake Wilson, which has done other ditch projects for the county ditch before, to do the work approved by the ditch committee. Johnson said the estimated cost of the dredging was a little under $20,000. The funds would be paid for out of the judicial ditch fund, which is funded by rural land owners who benefit from the ditch, according to Shaffer, who said there was not a contract yet with Johnson Ditching.
Shaffer said the committee wants to get the dredging done this summer. He said the committee is looking at the project as a“public service” for the Pipestone residents and that there are other portions of the ditch that also need work done.
“It’s not going to eliminate flooding,” Shaffer said. “It’s only going to make people in Pipestone happy that we did something.”
He said the dredging might help “a little,” but there are other issues such as land use and development in the area since the ditch was created in 1928 that contribute to the flooding. He said the homes built in the flood plain since then will still flood if there is a significant rain, as there has been on several occasions in recent years.
“Normal drainage and a 3-inch rain will go down the ditch,” Shaffer said.
Effectiveness of dredging
Shaffer is not alone in his belief that dredging the ditch might not accomplish much.
“When you get an 8-inch rain, no matter what the landscape, you’re going to have problems,” said Luther Aadland, program consultant for the Minnesota Department of Natural Resources (DNR) River Ecology Unit, when speaking with the Pipestone County Star last fall.
He said dredging can increase the slope and capacity of the ditch and move water more quickly, but the drawback is that the water moves to other properties down stream. He said the fast moving water can also cause erosion along the banks bringing pollutants into the water.
Better solutions, he said, are to create meandering channels, grass lands and off-channel storages that reduce flooding downstream by giving the water somewhere to go. He said zoning to prevent people from building and living in a flood plain is effective also because it opens up the flood plain and again creates more storage area when the water is high. He said buyouts of the properties in the flood plain could be used to relocate people.
The city of Pipestone used a DNR grant to buy out residents of the Tianna Trailer Park for that reason back in 2011.
“These things are never easy and it’s always harder to do the right thing than the easy thing,” Aadland said.
Rita Weaver, chief engineer and state drainage engineer with the Minnesota Board of Water and Soil Resources (BWSR), said dredging can be helpful if the ditch needs maintenance. Weaver said that over time ditches deteriorate and debris can build up, which some have said is an issue in the county ditch. Dredging restores a ditch to its original capacity.
She said evaluating the cause of the flooding is important in determining a solution. If the flooding is due to very wet years and heavy rains, as has been the case in recent years, she said dredging might not help. In that case, more major solutions like those suggested by Aadland or others such as wetland restoration or buffers might be needed. Those solutions, however, can be costly and involve reviews and permitting by multiple agencies.
Weaver said dredging is the most cost effective option and a good first step.
“It’s the easiest place to start,” she said.
She said BWSR has programs to help with larger scale projects to address ditch flooding such as the Conservation Reserve Enhancement Program (CREP), which could help reduce flooding by putting projects in place upstream to keep more water on the land instead of having it run downstream. Another is the Multipurpose Drainage Management grants, which she said are similar to CREP, but are awarded to counties or watersheds instead of individual land owners and used for multiple projects that could reduce flooding.
Source: pipestonestar
