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Road Closure: Carpenter Way Area Street Closures View Closure
Climate and Environmental Impact

Could green infrastructure replace the tunnel system?

Covers how many green stormwater infrastructure (GSI) and source control projects would be needed to match what the tunnels achieve, and whether that is even possible.

This possibility was evaluated as part of the CWP. It was concluded that replacing the tunnel system using green infrastructure and source control would not be feasible given the volumes of overflow reduction required to meet the water quality objectives and completion schedule.

The regulatory agencies agreed that ALCOSAN should move forward with the tunnel system while continuing to invest in GSI and source control through our GROW program and gave more time to ALCOSAN to do so. The information to be collected through the GROW program must be continuously analyzed by ALCOSAN to evaluate the potential impact on the tunnel system and make relevant adjustments.

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