Harris County Commissioners Reaffirm Need for Minimum Drainage Standards in Region
On Tuesday, April 5, 2022, Harris County Commissioners Court reaffirmed the need for minimum drainage standards in the region. The program called “Fix Flooding First,” was started in 2020 by the Harris County Engineering Department. It is designed to help prevent flooding, not just fix it. The idea: to bring all municipalities and other counties that drain into Harris County to adopt minimum drainage standards.
Altogether, the West Fork and East Forks of the San Jacinto with Peach and Caney Creeks, all of which drain through rapidly developing Montgomery County sent 300,000 cubic feet per second into the Lake Houston Area during Harvey.
To see how many square miles are being drained upstream from you, consult this map. Almost half of the watersheds in Harris County originate outside the county.
Seeking Agreement on Five Measures
Five minimum measures, recommended by the Office of the County Engineer and Harris County Flood Control District, include:
1. Use Atlas 14 rainfall rates for sizing storm water conveyance and detention systems.
2. Require a minimum detention rate of 0.55 acre-feet per acre of detention for any new development on tracts one acre or larger. A single-family residential structure and accessory building proposed on an existing lot is exempt from providing detention.
3. Prohibit the use of hydrograph timing as a substitute for detention on any project, unless it directly outfalls into Galveston Bay.
4. Require “no net fill” in the current mapped 500-year floodplain, except in areas identified as coastal zones only.
5. Require the minimum Finished Flood Elevation of new habitable structures be established at or waterproofed to the 500-year flood elevation as shown on the effective Flood Insurance Study.
Harris County Has Little Leverage
Harris County doesn’t have much leverage in this request. It can’t force neighbors to do anything. Compliance more or less depends on good will and a recognition that flooding in Houston and Harris County can affect the whole region negatively. Working together ultimately benefits everyone.
However, Harris County does have two small carrots. The County hired a consultant to review existing flood regulations in neighboring jurisdictions and make recommendations to bring them up to minimum standards. The county also can approve (or reject) partnership projects with those neighbors.
Mixed Results; No Change Since January
As of the start of this year, the program had met with mixed success.
- 16 municipalities (including Houston, Humble) and Waller County had successfully upgraded their regulations.
- 14 municipalities and Fort Bend County had completed the analysis of the regulations but not fully upgraded them yet.
- 8 (four municipalities and four counties) did not respond to the offer of the analysis, refused it, or refused to participate.
As of last Tuesday, those results had not changed since January when I last reported on this program. The same municipalities and counties were in each category. Liberty and Montgomery Counties both fall into the last category (did not respond or refused).
Establish Precedent for Regional Cooperation Now
Harris County can spend billions on flood mitigation, but if upstream communities keep sending more water downstream, we may never see improvement.
Ironically, all the upstream communities will be downstream from other developing communities in the future and may be in the same position that Harris is in today. It would be good to establish precedent for regional cooperation now that they could use themselves in the future.
Studies show that for every dollar spent on flood prevention, they can save five dollars on flood mitigation. That’s money that could go into improving the quality of services and infrastructure in communities….without forcing people through the trauma of flooding!
Posted by Bob Rehak on 4/7/22
1682 Days since Hurricane Harvey