City of Des Moines US 6 Hubbell Avenue Improvements

Background

The City of Des Moines and the Iowa DOT sought to transform the four-lane, vehicle-centric US 6 (Hubbell Avenue) corridor into a divided, multimodal urban roadway. Improvements were intended to enhance intersection safety, improve traffic operations, and provide bicycle and pedestrian access along the corridor. Foth was tasked with conducting a safety study and providing project coordination, preliminary design, and final design based on study findings.

Approach

Our team presented three design alternatives, and our recommendation to include 90-degree approaches to US 6 and install a median along US 6 to minimize left turn movements were accepted. We also recommended realigning and installing traffic signals at the E Euclid Avenue and E Douglas Avenue intersections.

During the design process, the city identified the opportunity to improve the quality of stormwater discharge into the adjacent Fourmile Creek. As an urban stream, Fourmile Creek had been negatively impacted by pollution and erosion, and flooding was a major concern for the creek’s watershed. To address these concerns, our team designed a stormwater wetland that treats storm flow prior to discharge into the creek.

Results

Roadway services included roadway design, hydraulic analysis and storm sewer design, floodplain permitting, utility coordination, traffic signals, lighting, and staging and traffic control. Final design included reconstruction 3,400 LF of US 6, realignment of E Euclid Avenue and E Douglas Avenue, and reconstruction of connecting side roads at E 37th Street and E 38th Street. We also provided project coordination with the Iowa DOT, Des Moines Water Works, DART, private utilities, and individual stakeholders along the corridor.

Work on the wetland included hydraulic analysis, floodplain permitting, and utility coordination. Following construction, the area’s sediment basin filters 90% of stormwater runoff that flows through the wetland. The basin has the capacity to retain food flows , helping mitigate flooding to downstream neighborhoods and businesses. The wetland also is an amenity to the creek’s greenway, providing an aesthetic natural area within a highly developed portion of the city.