The purpose of the Columbus Circle Storm Drainage Improvement Project was to eliminate localized structure and road flooding. The watershed covers an area of 137 acres comprised of urban residential land use. The project included the analysis of 700 linear feet of open stream channels and 7200 linear feet of closed pipe system. Armstrong Glen teamed with stream specialists to identify areas where natural channel design could be utilized to mitigate erosion while minimizing channel armoring.
Natural channel design was incorporated into the project along the open channel at the intersection of Alleghany Street and Denver Avenue. The stream banks were eroding due to the sharp bend between the culverts under Alleghany St. and Denver Ave. Armstrong Glen analyzed the channel and prepared a grading plan with permanent erosion control matting to eliminate future erosion. Stream specialists designed j-hooks to direct the energy towards the center of the channel, thereby reducing scour potential.
Work for this project included field surveying, hydrologic and hydraulic modeling, planning report preparation, public involvement, easement mapping, final construction drawings, and construction phase services. Construction cost: $6,200,000. Project duration including planning study, design, and construction: May 2001 to November 2007.