Lawrence Avenue Underflow Sewer System: Monitoring and Evaluation

摘要

A new and bold concept in design of urban drainage systems was developed as a step forward in the solution of combined sewer overflow problems. A deep tunnel in bed rock about 200 to 250 feet (61 to 76 m) below the surface was designed and constructed for the Lawrence Avenue drainage basin in Chicago. Flows and pollutants to the river and treatment plant were monitored. Performance of the tunnel system in capturing flows and pollution was evaluated with the help of calibrated computer models. Groundwater was monitored to assess the project influence on the aquifer. The results show that this design is very effective in reducing combined sewer overflows to the waterway. Tunnels capture smaller storms, and trap a significant portion of the first flush of pollutants from larger storms which is subsequently pumped to the treatment plant.