Renville County approves small wetland restoration in County Ditch 66
The small wetland restoration will benefit drainage in the system, but the project also made evident the challenges faced in holding water on the landscape. The project's approval came only after modifications to address concerns of adjoining landowners.
OLIVIA — The challenges of restoring wetlands and holding water on the agricultural landscape were evident when the Renville County Drainage Authority last week approved a small wetland restoration project.
The Renville County Board of Commissioners, acting July 27 as the drainage authority, approved the approximately one-acre wetland restoration but only after requiring modifications to expand the capacity of tile lines that will be rerouted due to the project. Joseph Amberg petitioned to restore the small wetland on property near County Road 17 south of Olivia.
Two hearings were held on the project, and adjoining landowners raised concerns about the original restoration plan developed for the project by the Minnesota Board of Water and Soil Resources. At the July 27 hearing, BWSR Engineer Tom Wenzel said revisions made to address concerns raised at a June 22 hearing should increase the capacity of the rerouted tile by as much as 100%.
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Renville County wants plans revised for small wetland restoration The Renville County Ditch Authority wants to see modifications to the plans for a proposed wetland restoration south of Olivia in the County Ditch 66 system. Neighboring landowners voiced concerns at a public hearing.
Cleaning out ditch around Olivia proves costly A project to clean out Renville County Ditch 66 that was rerouted around Olivia in 1998 threatened to be costly from the start, and the final bills prove it.
Landowners expressed their concerns whether the second design could achieve the projected results, however. The concerns included whether a flexible, dual-wall tile that would be installed in place of existing “stick” tile would provide the same drainage efficiency.
The landowners also noted that plowing in the flexible tile, as compared to digging a trench for laying tile, brought the risk of breaking underground tiles not known to the engineers.
After two hours of discussion, the drainage authority approved a plan that calls for using a 12-inch diameter, flexible dual-wall tile for much of the rerouting, in place of mostly smaller diameter tile in the area.
Wenzel said the wetland would be only 1 to 2 feet in depth, and likely dry during much of the summer. It will provide storage by holding water from an approximately 40-acre watershed, and consequently benefit the drainage on adjoining agricultural lands. If the wetland is full of water, and an approximate 4-inch rainfall occurs, its overflow water will be discharged through a control device that will limit the flow rate.
The new requirements for expanded diameter tile will increase the project costs, but no estimates were provided. Wenzel said the use of flexible, dual-walled tile will be less costly than straight tile. He said the main purpose in using the flexible tile was to eliminate tile joints, which create long-term maintenance problems.
To approve the project, the commissioners had to find that the project met two criteria: It provides public and private benefits, and it does not adversely affect the drainage of the adjoining landowners.
The benefits of the wetland restoration include improved drainage for the County Ditch 66 system due to the temporary storage of water on the landscape.
The wetland restoration will also provide environmental benefits. It will provide seasonal habitat for migratory waterfowl and other wildlife. It will reduce the loads of pollutants and sediments reaching the Minnesota River by allowing them to settle in it. Wetland restorations are considered among the most cost-effective ways to reduce nitrate and sediment loads in waterways, and are a means of reducing the impact of large volume flows that cause streambank erosion.
County Ditch 66 is one of the larger drainage systems in the county, and it has proven to be a costly system. It was reconstructed in 1998, at a cost of $2.2 million, in the area from Bird Island to Olivia, where it was rerouted around the community. It flows to the East Fork of Beaver Falls Creek and Minnesota River.
The system required a more than $1.4 million clean-out and repair project two years ago.