End Man-Made Houston Flooding

Governance

Watersheds know no county boundaries, but flooding should be dealt with for an entire watershed.  Therefore, this petition calls for a single, properly funded intra-governmental body with endorsement and participation from all the city and county public entities in the 13-county Houston-Galveston Area Council (H-GAC). Multi-County Flood Control Districts are not new, for example, Denver has one, but the proposed H-GAC Flood Control District would likely be the largest. The H-GAC Multi-County Flood Control District must be commissioned to have ultimate authority and accountability for all stormwater related issues, including:  

1.        Applicability:  Regulation, policies, and practices must apply universally to the entire H-GAC area, and to all watersheds, not just floodplains.  Detention deficits must be addressed – that which is needed today but was not installed in the past – with a plan on where and how to install detention that meets today’s needs.


2.        Designation: Until the H-GAC Multi-County Flood Control District can be assembled, there must be no new adverse impacts from construction.  Any elevated properties or concrete on the ground must be mitigated with an equal amount of detention.    This effectively freezes flooding close to current levels.


3.        Approvals:  Any new stormwater discharges or projects that will alter run-off into a given watershed must be reviewed and approved by the Multi-County Flood Control District for that watershed.


4.        Regulation: In addition to ultimate responsibility for harmonizing regional ordinances, the District must regulate impacts of impervious cover and fill on storm water drainage and bayou capacities.


5.        Enforcement: Existing and new regulation must be enforced with no variances or grandfathering.  


6.        Development: To prevent future flooding, new development and redevelopment must be in compliance with the new regulations and in accordance with good engineering practices 


7.        Incentives: Financial incentives must be available to encourage landowners to retrofit properties to these guidelines, including conversion to pier-and-beam construction. Penalties must be applied for failure to comply.


8.        Documentation: Chapter 9 of Houston’s Infrastructure Design Manual (IDM) must be rewritten to reflect the technical requirements addressed herein and otherwise address flooding. Specific sections of the IDM must be removed and made part of the Houston Code of Ordinances so that they are subject to public comment and City Council oversight.


9.        Records: To promote transparency and cooperation, the H-GAC Multi-County Flood Control District must keep records in electronic format that the public can easily access and search. 


10.      Research: Policy decisions must be based on the most advanced modeling available, including accurate elevation mapping and two-dimensional flow analysis.  Maps and models must be updated ongoingly.

Technical:

This is a partial list of technical issues that should be addressed.

1.        Fill: Only existing dirt on-site should be used for increasing building elevation.


2.        Detention: Total detention must be sufficient to prevent structural flooding in a 100-year event. Any detention mitigation banking must occur within the same square mile as development.


3.        Planting: Native riparian, water-absorbing grasses and trees must be planted in detention areas.


4.        Detention: Including capacity from all drainage systems, it is recommended that there must be a total of  640 acre-feet of detention capacity within each square mile of the H-GAC area (100% mitigation); currently, various county agencies require from 320 to 640 acre-feet of detention within each square mile.


5.        Runoff Coefficient: Within all urban areas street drainage must assume urban runoff coefficients of 0.9 or greater.


6.        Drainage: Appropriate Manning numbers must be used in calculations to ensure safe flow rates and adequate capacity.  Establish rules limiting rates of flow off roofs of multistory buildings prior to entry into local drainage systems.


7.        Modeling: Before any drainage project is initiated, accurate and up-to-date elevations and two-dimensional flow modeling should be used to understand stormwater flow better so that flooding is not simply moved elsewhere. Develop an area-wide actively maintained modeling system so that accurate analysis can be done on every project prior to shovels in the ground.  Begin actively anticipating future development patterns and detention needs, particularly in the upper reaches of watersheds.

The federal government has paid more money to Texas for flood repairs than to any other state except Louisiana. It is well past time that we made the hard choices we need to make in order to stop this scourge on our population.

Please sign this petition to demand that the local, state, and federal agencies working in the Houston-Galveston area do their jobs and avoid more deadly, preventable flooding. Doing so will increase security and accelerate economic growth in the region.

Signed,

Prof. Jim Blackburn, Rice Severe Storm Prediction, Education and Evacuation from Disaster (SSPEED) Center