November 22, 2019

Ambitious Regional Flood Planning Finally Underway

Having previously pitched the idea, worked out all the details, secured partner participation and funding commitments, and entered into interlocal agreements to seal the deal, the final step of awarding the engineering contract so work could begin felt somewhat anticlimactic.  It has taken us the better part of a year to get to this point, quite a bit longer than we’d hoped based on our partners’ initial expectations, but we got it done and the Bellaire Master Drainage Concept Plan is off and running.  This partnership among the City, Harris County Flood Control District and TxDOT is absolutely essential to Bellaire and the surrounding area if we are to achieve meaningful flood relief, especially in more extreme storm events that no amount of local improvements could contain.  Regional problems require regional solutions, and this could be the start of something big.

Sheet flow patterns fundamentally altered by decades of intensive development throughout our area make it easy to see how Bellaire’s local drainage systems are overwhelmed by outside storm water.  The IH-610 system running right through the middle of the City is severely undersized and the freeway itself acts as a dam, as does the railroad berm at our eastern boundary.  Even with all the added capacity from Project Brays, to fully benefit from that we need to reroute the outside water and improve our own north/south flows into the Bayou.

By working to keep the outside water out, and mitigating barriers to overland flow and moving it efficiently downstream, the goal is to restore the original flow patterns contained within each north/south system, serving essentially as individual subwatersheds.  We’re talking about some majorly ambitious, game-changing regional infrastructure projects over many years to come.

The Master Drainage Concept Plan is the necessary first step, to determine and evaluate the feasibility and cost-effectiveness of potential improvements, and to provide the technical support the City and our partners will need to compete for funding to perform subsequent phases of engineering and design work, and ultimately construction.  It will include detailed cost-benefit analyses, based on the model typically required for grant applications.  Identification of appropriate funding sources for Plan implementation is also a part of the project, and the partnership itself is an encouraging sign in that regard as it represents a shared seriousness of purpose and an acknowledgment that these bold (and expensive) ideas are worthy of future consideration for cost participation.

Among the possible improvement alternatives to be studied, with varying degrees of complexity and cost, are:  enlargement of the main storm sewers for greater conveyance capacity; massive underground flood tunnels straight to Brays Bayou, with associated siphons and pump stations; intermittent detention ponds to collect and reduce flows to the existing storm sewer system; surface channels to capture and convey sheet flow; relief structures through IH-610 and the railroad berm to reduce or eliminate their damming effect; and oversized storm sewers, with supplemental pump stations, to both increase conveyance and lower peak water surface elevations by providing inline underground detention.

With the multiple stakeholders involved and obvious public interest, there will be an emphasis on communication and engagement throughout the development of the Plan.  The engineering team will host periodic stakeholder meetings to discuss their assumptions, methodologies and findings, and a series of public meetings, including with our citizen Flood Hazard Mitigation Task Force, to provide updates and progress reports and to solicit public input.  There will also be a dedicated website to keep the public informed about the project.

Though it has taken us longer than expected to finalize the arrangements with our partners, we’re no less excited about this significant undertaking and the opportunity to make some real progress on regional flood control.  Originally we’d set out to study our north/south arterials on our own, as the logical next step in our local drainage program; expanding the scope to cover a wider regional area was definitely worth the wait.   Our continued thanks to Harris County and TxDOT for co-sponsoring the Plan and for their commitment to working with us in seeking the best solutions to our shared challenges.

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