Crow Wing County CSAH 20 Ahren’s Hill Improvements Recognized by MnSPE

Widseth Smith Nolting’s CSAH 20 Ahren’s Hill project was named a one of the 2011 Seven Wonders of Engineering by the Minnesota Society of Professional Engineers (MnSPE). The announcement came during MnSPE's 2011 Engineering Week Awards and Recognition Banquet, February 25, 2011, at Target Field in Minneapolis. Accepting on behalf of the team and Crow Wing County were Tim Houle of Widseth Smith Nolting, Stephan Gale of Gale-Tec Engineering, and Duane Blanck, retired Crow Wing County Highway Engineer.

The annual Seven Wonders of Engineering Awards Competition recognizes outstanding achievements in the field of engineering.

After eight years of construction, improvements to Riverside Drive culminated in the challenging segment perched along Ahren’s Hill overlooking Gilbert Lake. The 0.9 miles of improvements addressed significant safety issues, stormwater runoff, and poor roadbed subgrade and foundation.

Widseth Smith Nolting and Gale-Tec Engineering combined talents to design a roadway and a 2,950-foot-long vegetative-faced reinforced soil slope (RSS)—believed to be one of the largest in the Midwest, in terms of area and length. The intricate installation of the RSS made it possible to meet Minnesota State Aid standards for the roadway and storm sewer improvements, allowed the uphill slope to remain largely undisturbed, minimized disturbance on the downhill slope, and maintained a natural-looking view from the lake. Vegetation grew extremely well in the RSS’s rich, organic material. Plants and undergrowth were thriving within a month of installation. After just two months, it was difficult in some places to see the face of the RSS, creating a grand “Chia Wall,” as it came to be known.

As the firm of record, Widseth Smith Nolting of Baxter, Minn., provided preliminary design phase services, public relations assistance, final design and bid package preparation, bidding phase assistance, and on-call assistance during construction, which was administered by Crow Wing County personnel. GaleTec Engineering, Wayzata, Minn., designed the reinforced soil slope and provided periodic assistance to the County during bidding and construction.

General construction was provided by Rachel Contracting, Inc., of St. Michael, Minn., and paving was completed by Anderson Brothers, Inc., of Brainerd, Minn.

For additional information on this project, please contact Tim Houle, PE.