SPI Insights

The Harris County Flood Control District expects to begin the third phase of its feasibility study on countywide stormwater conveyance tunnels this fall.

District engineers will determine the scope elements of the third phase of the feasibility study in late 2022 and could begin the phase in the spring of 2023.

The first phase estimated total project costs in 2019 dollars at $1 billion for a 25-foot diameter tunnel and $1.5 billion for a 40-foot diameter tunnel.

The third phase likely will consider further engineering analyses (validation of assumptions, hydrologic and hydraulic modeling, geotechnical investigations, and evaluation of active versus passive systems.

It will examine the countywide economic benefits of adding a tunnel system to our current stormwater management network, as well as the process needed to integrate the tunnel system within existing neighborhood drainage, bayous, and stormwater detention basins. Additionally, Phase 3 includes further environmental analysis and exploring funding strategies to pay for a tunnel system.

Following Hurricane Harvey in 2017, county leaders challenged the district to consider all innovative technology for reducing the risk of flooding. Voters in 2018 approved a bond program that includes $20 million for the feasibility study.