Matrix Design Group contracted with the Colorado Department of Transportation (CDOT) to support the Upper Clear Creek Watershed Authority (UCCWA) in the design of two sedimentation basins within the CDOT right-of-way to capture sediment, mine waste, and stormwater runoff from small tributaries of Clear Creek north of I-70. The project was completed via a Clean Water Act Section 319 grant.

Matrix provided engineering analysis and prepared construction documents for these two sediment control basins. Matrix was selected for the design project based on the company’s extensive experience in hydrology, hydraulics, water quality, Best Management Practices (BMP) design, and previous experience developing the Sediment Control Action Plan for the I-70 corridor.  

The sedimentation basins were designed for ease of maintenance coupled with adequate storage volume for the capturing of sediment. Matrix worked with project sponsors to establish appropriate criteria given the limited site constraints. Several hydrologic models were developed for the two watersheds of Hoosao Gulch and an unnamed gulch near Dumont to determine an appropriate design event.

Matrix developed concepts for alternative pond location sites and configurations. The most appropriate sites were selected, and Matrix graded sedimentation basins into the sites and determined the available storage volume. The design considered maintenance access, appropriate width/length/depth relations, forebays, pond bottom lining, and outlet structures. Site plans and details were developed, and deliverables were made to sponsors during concept design, 50% design, 90% design, and final design. Cost estimates were prepared with each design submittal.