The original Nettle Creek Aqueduct was built in the mid-1840s in Morris, Illinois, and had undergone several reconstructions throughout its history. Following a partial collapse caused by flooding in 2013, the aqueduct was removed to prevent water impediments in Nettle Creek.
EXP provided multidisciplinary structural, hydraulics, surveying, civil, site and public involvement services for the design of a new replacement aqueduct.
Design of the new aqueduct
EXP evaluated restoration or replacement of the aqueduct while considering its historical significance. The Illinois and Michigan (I&M) Canal waterway prism, towpath along the north side and pedestrian path along the south side were also considered in conjunction with this evaluation. Based on topographic and hydraulic surveys, geotechnical investigations, material sampling and testing and underwater inspection, the team decided replacement was the preferred option.
The most recent version of the aqueduct was a single span structure with decorative arches meant to support secondary walkways rather than act as the main weight-carrying mechanism. EXP’s schematic design consisted of a single span structure that replicates the look of an arch as a façade element.
Hydraulic elements
The original aqueduct had a 45-foot-wide opening, which caused a restriction in the Creek during flood events and created a significant hydraulic jump at the structure. This occurs when fast-moving water abruptly flows into an area with lower velocity, causing the water to rise quickly. To decrease this hydraulic jump, and in turn increase its ability to withstand storms and decrease flood elevations upstream in the town of Morris, the aqueduct’s opening was widened to 140 feet.
Services
Structural, Hydrology/Hydraulics, Survey, Inspection, Civil/Site, Public Involvement