The Connecticut Department of Transportation selected BL Companies to provide on-call engineering and related consulting services to the Department’s Hydraulics and Drainage unit. Typical assignments involve detailed drainage, hydraulic and floodplain studies for highway or railroad bridges over waterways, culverts, storm drainage systems, dams and related facilities for engineering projects. BL Companies provided services under the on-call contract for Culvert Improvements under the List 21 Bridge Rehabilitation Program.
BL Companies provided services under the on-call contract for:
Culvert Improvements under List 21 Bridge Rehabilitation Program – Under this program, BL Companies provided hydrologic and hydraulic analyses using the Natural Resources Conservation Service (SCS) Method, the Rational Method, StreamStats, and US Geological Survey regression equations to determine the design flows for the culverts. Flows determined in the hydrologic analyses were used to perform hydraulic analyses for existing, natural and proposed conditions. Preliminary and final hydrologic and hydraulic reports were completed for each culvert. Preliminary engineering, including construction access, regulated area impacts and environmental permitting determinations, were also performed on this assignment.
U.S. Route 1 Drainage Study (State Project No. 35-191), Darien, CT – BL Companies provided hydraulics and drainage engineering services to Connecticut Department of Transportation (CTDOT) for a project area along the U.S. Route 1 between Corbin Avenue and Stony Brook in Darien. The outlet lf this system discharges to a watercourse that is influenced by coastal and tidal flooding from Long Island Sound. BL Companies performed a drainage study of the Route 1 drainage system watershed using aerial photography/photogrammetric mapping and topographic information provided by CTDOT. Historical photogrammetic, USGS mapping and aerial photos were reviewed to identify any change of water flow pattern. Stony Brook and Goodwives River was reviewed for flow pattern. A drainage analysis of the existing Route 1 storm drainage system was also performed in accordance with the CTDOT drainage manual. The analysis results identified deficiencies as the cause for flooding along the Route 1 corridor. Two proposed design alternatives were developed to address the deficiencies and depicted on conceptual layout plans. Preliminary cost estimates for construction cost were also provided.