AMES, Iowa – Dec. 22, 2025 – The Iowa DOT is proposing to replace the bridge along Iowa 146, over the North Skunk River in northern Mahaska County. The project would impact Robertson’s Access.
Robertson’s Access will be closed for the duration of construction. Users will not be able to access the North Skunk River boat ramp or other recreational amenities (i.e., campground, hunting, fishing, etc.) offered by the park for the duration of the closure. In addition, the Iowa DOT would acquire approximately 0.02 acres of permanent right-of-way (ROW) from Robertson’s Access to accommodate the new bridge structure. The area proposed for acquisition is green space.
Robertson’s Access is a 42-acre property split between the Poweshiek County Conservation Board (PCCB) and the Mahaska County Conservation Board (MCCB).
- The southern 35 acres are managed by MCCB and includes a primitive campground, nature trail, restrooms, picnic tables, and river access to the North Skunk River.
- The northern 8 acres is managed by PCCB. This property consists of river bottom timber and does not have any recreational amenities or designated access points from Iowa 146 or 540th Avenue.
The area proposed for acquisition consists of green space and may include the clearing of a few trees. No other amenities provided by Robertson’s Access will be impacted. Impacts to the green space will include grading and placement of rock riprap.
Robertson’s Access has been determined to be a Section 4(f) resources and the project is expected to have a de minimis impact on the properties.
Section 4(f) of the U.S. Department of Transportation Act of 1966 was enacted as a means of protecting publicly owned parks, recreation areas, and wildlife/waterfowl refuges, as well as historic sites of local, state, or national significance from conversion to transportation uses.
De minimis impacts are defined as those that, after consideration of any measure(s) to minimize harm (such as avoidance, minimization, mitigation, or enhancement measures), do not adversely affect the activities, features, and attributes of the Section 4(f) resource.
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For questions about the project, contact:
Blake Walter, Location and Environment Bureau
Iowa Department of Transportation
800 Lincoln Way, Ames, Iowa 50010
Phone: 855-925-2801 Project Code: 4735
Email: e64358@publicinput.com