Watersheds of the San Jacinto River Basin

TWDB Needs Feedback on Ranking Method for State Flood Plan

The Texas Water Development Board (TWDB) is soliciting feedback on its proposed scoring matrix to rank efforts for the state’s first flood plan. Each region has submitted proposed projects. The scoring matrix will help rank order them statewide. And the deadline is April Fools’ Day.

TWDB has provided several spreadsheets that show how the criteria and weights would affect ranking of sample projects. But understand that TWDB is only soliciting comments on scoring criteria and their weights at this time, not the rankings of the limited sample. All this is DRAFT data, not final recommendations.

39 Factors in Three Different Categories and Three Groups

TWDB has proposed weighing the relative merits of 39 factors that span three categories with benefits in three more groups:

  • Flood Management Evaluations (Studies)
  • Flood Mitigation Projects
  • Flood Management Strategies

TWDB uses three types of factors:

  • Flood risk
  • Risk reduction
  • Other related factors

“Other” includes such factors as cost and environmental benefits.

The 39 factors include:

  1. Emergency Need (Y/N)
  2. Estimated number of structures at 100yr flood risk
  3. Residential structures at 100-year flood risk
  4. Estimated Population at 100-year flood risk
  5. Critical facilities at 100-year flood risk (#)
  6. Number of low water crossings at flood risk (#)
  7. Estimated number of road closures (#)
  8. Estimated length of roads at 100-year flood risk (Miles)
  9. Estimated farm & ranch land at 100-year flood risk (acres)
  10. Number of structures with reduced 100yr (1% annual chance) Floodplain
  11. Number of structures removed from 100yr (1% annual chance) Floodplain
  12. Percent of structures removed from 100yr (1% annual chance) Floodplain (Calculated by TWDB from reported data)
  13. Residential structures removed from 100yr (1% annual chance) Floodplain
  14. Estimated Population removed from 100yr (1% annual chance) Floodplain
  15. Critical facilities removed from 100yr (1% annual chance) Floodplain (#)
  16. Number of low water crossings removed from 100yr (1% annual chance) Floodplain (#)
  17. Estimated reduction in road closure occurrences
  18. Estimated length of roads removed from 100yr floodplain (Miles)
  19. Estimated farm & ranch land removed from 100yr floodplain (acres)
  20. Cost per structure removed from 100-year floodplain
  21. Percent Nature-based Solution (by cost)
  22. Benefit-Cost Ratio
  23. Water Supply Benefit (Y/N)
  24. Severity – Pre-Project Average Depth of Flooding (100-year)
  25. Severity – Community Need (% Population)
  26. Flood Risk Reduction
  27. Flood Damage Reduction
  28. Critical Facilities Damage Reduction
  29. Life and Safety
  30. Water Supply
  31. Social Vulnerability
  32. Nature-Based Solution
  33. Multiple Benefits
  34. Operations and Maintenance Costs
  35. Admin, Regulatory Obstacles
  36. Environmental Benefit
  37. Environmental Impact
  38. Mobility
  39. Regional

Factors (in Risk, Risk Reduction and Other groups) may receive weight in one, two or all three main categories (Evaluations, Projects, Strategies).

Intent: Consistency Across All Regions Statewide

The intent of the TWDB ranking method for the state flood plan is to provide a consistent approach to be used across all Texas regions. The goal: to systematically address the flood hazards with most population, properties and critical facilities at risk in the state during a 1% annual chance flood.

TWDB bases all risk on 1% annual chance/100-year flood estimates.

Areas with widely varying measurements such as population will have answers normalized. Basically, this means adjusting widely varying scales to a common scale (such as 0 to 1) to facilitate comparison.

More Background, Sample Data, Providing Feedback

All relevant ranking workbooks, documents, and the link to the online survey tool are available on the State Flood Planning webpage.

Provide your feedback on this page. It’s a four-question survey about the:

  • Plan in general
  • Evaluations
  • Projects
  • Strategies.

The deadline to submit feedback is Saturday, April 1, 2023.

Importance of Feedback

We have seen how seriously the weights given to such rankings can skew priorities. Consider, for instance, the Equity Prioritization Framework adopted after the fact by a Harris County Judge and two commissioners for proposed 2018 Flood Bond Projects (unrelated to these projects).

So, if you have reservations with the TWDB scoring system, register your complaints NOW. My biggest concerns are that it’s hard to understand. It also contains broken links and typos that get in the way of understanding.

But understanding is critical. Many of the flood-reduction projects needed on the periphery of Harris County will need be addressed by state money. That’s because 10 of our 23 watersheds originate outside the County. I guess that would fall under #39 Regional. But…

The proposed scoring matrix gives ZERO weight to Regional benefits.

That’s kind of strange for a regional plan designed to encourage solutions that cross jurisdictions. Scoring matrix penalizes people on the periphery of large urban areas like Harris County.

watersheds in Harris and surrounding counties

I’ve already sent my feedback on that one.

Inconsistencies? TWDB refers to FMS as Flood Management Strategy on its spreadsheet and Flood Management Solution in introductory text.

Another example: In its spreadsheets, footnotes describing the listing of criteria do not correspond in all cases to the criteria listed. Nor does a link work to a supposed explanation of the criteria.

And there’s no description that I could find of how all these categories, measurements and groups fit together.

Finally, it’s not clear how they will treat areas that have a 50% annual chance of flooding (2-year flood). We’ve seen in highly urbanized areas that – after spending hundreds of millions of dollars in some watersheds – the best we can do achieve in some areas is a 25-year level of service. Achieving better would require buying out thousands of homes. What will happen in such cases?

Please make the effort to provide public feedback.

Posted by Bob Rehak on 3/20/2023

2029 Days since Harris County

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.