Improving Flood Risk Knowledge. Proposing Solutions

A Draft Flood Plan for the Region

Key Finding: Lack of Information
Emphasis on Preparedness
How to Manage Development

Public Meeting in-person, Sept. 27, 5:30-7:30 pm. White Oak Conference Center, 7603 Antoine

Public Meeting virtual online, Sept. 29, 5:30-7:30 pm

Public Comment through Oct. 27

Public Comment through Sept. 30 on the Harris County Flood Control District’s proposal for county-wide stormwater tunnels

Sept. 26, 2022

Harris County does not have adequate information about where and how the county floods.

In fact, the entire watershed draining into the San Jacinto River does not have adequate information about flooding. This watershed includes Harris and parts or all of ten other counties from Galveston in the south to Huntsville in the north.

But the Harris County Flood Control District is working on it. (Back in 2017 the Army Corps of Engineers was going to work on it too and that work would have been done by now. But that project was changed.)

The lack of information is just one of the findings (p. 30) of a state-sponsored flood planning group which has been meeting and gathering information for nearly two years. The group of mostly citizen volunteers represent a variety of interests, including small business, agriculture, the environment, municipalities, water and electric utilities, the public, and more. Aided by public officials and the engineering firm Freese and Nichols, the group, known as the San Jacinto Regional Flood Planning Group or Region 6, recently released a massive draft report, which will be evaluated by the Texas Water Development Board, incorporated into a state flood plan, and sent to the state legislature in 2024 for possible funding. The state flood plan is to be updated every five years.

Managing Development. Being Prepared

The population of the San Jacinto region is expected to grow by one-third by 2050, and “one of the largest challenges” associated with this population increase, according to the report, is “determining how to manage development responsibly and continue to preserve the region’s natural resources.” (p. 24)

Increasing flood preparedness and improving flood management regulations and ordinances are also among the top priorities detailed in the report. (pp. 154 and 172)

The public can comment until Oct. 27 on the draft report, which is 302-pages long plus thousands of pages of appendices and maps and stuff. There are also two public meetings about the plan this week, one in-person Tuesday, Sept. 27, and the second virtual on Thursday, Sept. 29.

Big Bottom-Up Flood Planning Effort

The regional group is one of fifteen established by the state legislature in 2019. Based on the watersheds of the major rivers draining the state, the groups operate under the technical guidance of the Texas Water Development Board.

The purpose of the entire project is to “improve flood risk knowledge and propose solutions,” according to James Bronikowski, manager of regional flood planning for the state board. The ongoing effort is “intended to be a transparent process which relies on public input,” though based on the number of website responses and attendance at public meetings, public input appears to have been modest so far. (p. 295)

A Variety of Potential Flood Risk Reduction Actions, Nature-Based, Expanded Benefit

Of the fifteen watershed planning regions, San Jacinto is the second smallest region but the most densely populated, with twice the population density of any other region. Harris County has the most people at risk of major flooding. (p. 82) The 5,089-square mile region also includes some 3,173 square miles of farming, forestry, and ranch land, mostly forestry and ranching. (p. 56)

The draft report identifies 650 potential actions that could help reduce flood risk in the region. These are divided into three groups: 1. evaluations or studies, 2. strategies or plans, and 3. actual projects, both structural and non-structural, though sometimes the difference between strategies and projects is unclear. These “actions” are largely if not entirely existing projects planned by local municipalities, counties, or districts. The basis for assessing these actions included high need and existing risk to critical facilities, no adverse impact, quantifiable flood risk reduction, and regional benefit.  (p. 32)

Incorporating nature-based practices in at least 90 percent of strategies and projects is a long-term (30-year) goal. (p. 30)

The report also expanded the traditional but controversial benefit-cost ratio, which tended to favor expensive properties. (p. 160) Projects and strategies can or should have other benefits like “public uplift, public education, low impact development features, and environmental benefits.” (p. 163)

Projects. Plans. Be Prepared. Keep Doing the Same Thing

The 374 potential evaluations (pp. 155 and 170) include watershed planning–flood mapping updates and master drainage plans; project planning and preparedness for $200.6 million. (p. 34)

The plan identifies a total of 64 strategies at a cost of $1.137 billion, the vast majority of which ($1.1 billion) would be for “buyouts or elevation of structures with high flood risk or historical flooding impact as well as land preservation and restoration programs.” (p. 34)

The remaining strategies include education and outreach, drainage improvements or maintenance, flood gages and warning systems. (p. 155) Additionally, retrofitting or hardening critical infrastructure against storms, burying power lines, land preservation, developing expertise in rescuing people from upper floors, hiring floodplain administrators are among the more detailed “strategies” on the list. (p. 1977)

None of these strategies refers explicitly to slowing the flow, stopping raindrops where they fall, (pp. 33-34) or managing flooding in place, (see also here) which is modern flood management.

However, there are numerous projects for building stormwater detention, removing structures from the floodplain, and purchasing land for preservation, including proposals from the Coastal Prairie Conservancy (formerly Katy Prairie Conservancy) to purchase, preserve or restore five square miles of land in Waller and Harris counties. (p. 1988)

Ike Dike

The draft plan recommends a total of 21 nonstructural projects, also including property buyouts and easements, and 13 structural projects for a total cost of $28.9 billion. (p. 33) Most of the nonstructural projects focus on preparedness. (p. 172)

The majority of recommended structural projects are so-called “channel improvements” proposed by the Harris County Flood Control District (p. 64)  and funded through the 2018 bond program. “Channel improvements” means repairing previously “improved” channels and streams, widening and altering, a continuous and outdated process which can contribute to increased flooding. (p. 154) However, the report seeks to mitigate potential downstream flooding problems by also recommending new stormwater detention basins. It’s unclear how many trees might be removed to be build new detention basins or whether removing trees for detention results in more or less detention. (Trees and vegetation deflect, soak up, and slow the rain and runoff.)

Recommended structural projects also include a tunnel, bridge replacements, and in at least one instance (p. 184), converting open stormwater ditches to curb and gutter drainage, despite the fact that earthen ditches are more effective and cheaper and easier to maintain (p. 2) than concrete curbs and gutters, which can increase flooding. (p. 183)

Recommended Structural Projects

Lower Clear Creek and Dickinson Bayou (p. 173)

Brays Bayou (p. 176)

Sims Bayou (p. 178)

Halls Bayou (p. 180)

White Oak Bayou (p. 182)

Greens Bayou (p. 184)

Caney Creek (p. 186)

East Fork of the San Jacinto River (p. 189)

Lake Creek (p. 190)

Peach Creek (p. 192)

Spring Creek (p. 193)

West Fork San Jacinto River (p. 195)

Coastal Storm Risk Management  (p. 197). The report claims that the Galveston Bay Surge Protection plan (known as the Ike Dike) has no adverse environmental impacts. (p. 2050) It does not mention the Galveston Bay Park Plan developed by the SSPEED Center at Rice to complement the coastal protection plan proposed by the Corps of Engineers and Texas General Land Office.