Blue Earth County recently acquired TH 66 through a turnback agreement with MnDOT and re-designated the route as CSAH 1, a Type III Natural Preservation Route. SRF and Gale-Tec Engineering assisted the County in correcting slope stability problems, erosion issues, and safety concerns due to sharp curves and poor sight lines under dense vegetation.
We compared alignment alternatives to improve safety and explored several wall/slope options to identify a cost-effective solution that would minimize impacts to adjacent properties and the natural environment. Reinforced Stabilized Slopes (RSS) were used in several locations to support the roadway, resulting in reduced impacts and costs.
Managing stormwater extended beyond the project footprint as more than 120 acres of drainage pass through the project area. We designed a creative way to convey runoff by collecting it at the top of the bluff in a specially designed riprap reinforced basin that funnels water into a 20% grade HDPE pipe that crosses under the county highway and down the steep slope.