Why 27% of People in the San Jacinto River Basin Live or Work in a Floodplain

No single authority in the San Jacinto River Basin has responsibility for flooding. Instead we have jurisdictional fragmentation. Multiple jurisdictions have limited authority to solve parts of our regional flooding problems.

The amended 2023 San Jacinto Regional Flood Plan (Page 1-13) indicates the river basin has:

• 11 Counties
• 83 Municipalities
• 980 other entities with flood-related authority

The Plan states, “Many of these entities have the authority to implement flood-related planning or projects but do not necessarily have the authority to implement or enforce floodplain management practices or standards.”

Collectively, our governmental organizations don’t match the nature of the problem: floodwater doesn’t respect jurisdictional boundaries. Yet people don’t want to give up their limited authority.

Local control doesn’t yield a collective solution.

Scarborough Example

The Scarborough Development in southern Montgomery County at the confluence of Spring and Cypress Creeks with the San Jacinto West Fork exemplifies the regulatory issue. Scarborough’s 5,300 acres lie between multiple jurisdictions.

• The proposed development is in Montgomery County but borders Harris County. Part of it is in Houston’s extra territorial jurisdiction (ETJ) and part isn’t.
• FEMA has updated its flood maps only for portions of the proposed development that lie within Houston’s ETJ.
• The development lies in Montgomery County Precinct 3 but will affect flooding in Precinct 4 and Harris County.
• Montgomery County doesn’t have a flood control district. Harris County does.
• Subsidence plagues the area and development will make subsidence worse. That could create a bowl in the landscape that increases flood risk. But the Lone Star Groundwater Conservation District is not considering subsidence in its new plans and will not acknowledge the concerns of the Harris-Galvestion Subsidence District.

Almost all of the proposed development lies in a floodplain or floodway. See below.

San Jacinto Regional Flood Planning Group Recommendations

To solve this problem and others like it, the San Jacinto Regional Flood Planning group is considering a series of legislative and regulatory recommendations that include:

• Creating, consolidating, or reorganizing regional flood authorities, flood-control districts, river authority programs, and drainage districts where broader regional coordination is needed.
• Supporting multi-jurisdictional cooperation at the evaluation, strategy and project levels.
• Clarifying roles and responsibilities for floodplain management in extraterritorial jurisdiction (ETJ) areas to reduce gaps or overlaps in responsibility for floodplain management, permitting, and drainage standards..

Three Aspects of Current, Self-Defeating “Flood Governance”

In business, management consultants commonly call this a “silo problem.” The more precise governance term is an “institutional collective-action dilemma,” compounded by a “scale mismatch.” 

Organizational Silos

McKinsey describes how optimizing individual functions in silos can undermine performance when trying to address a collective concern. In this case, think of departments as jurisdictions and the San Jacinto River watershed as the organization.

Theoretically, the San Jacinto River Authority (SJRA) has responsibility to control flooding throughout the river basin. But the SJRA almost never exercises it; they say they don’t have funding. The closest they’ve come to flood management is when they established a flood management division after Hurricane Harvey. But they have only managed a series of studies funded by others. And the studies have produced no tangible improvements to date.

So, by default, the watershed functions under multiple jurisdictions that each work within their own boundaries, responsibilities, budgets, and priorities. However, solving flooding problems requires collective action across jurisdictions.

Institutional Collective-Action Dilemma

Because floodwaters don’t respect jurisdictional boundaries, independent authorities need a shared solution. However, disagreements over costs, benefits, commitments, and loss of autonomy impede collective action.

Political scientist Richard Feiock describes this as “an institutional collective-action dilemma.” The term explicitly addresses barriers to coordinated decisions, including negotiation costs, constraints on autonomy, and difficulty securing enforceable commitments. Cooperation can benefit the region while requiring individual governments to accept obligations or surrender some discretion.

Scale/Institutional Mismatch

The geographic reach of the flooding problem exceeds the geographic reach of the institutions empowered to address it.

The term “scale mismatch” captures this dilemma. Some water-governance researchers call this the problem of institutional fit: whether the institutions managing a resource match its physical processes and geographic extent. Academic research has applied this concept specifically to flood planning across jurisdictions.

Fragmented Flood Governance and Conflicting Mandates

In Texas, authority to address flooding issues does not match the geographic extent of watersheds. And local incentives do not necessarily produce river-basin-wide results. The problem is especially acute for those who live or work at the intersection of jurisdictional boundaries.

Yes, multiple authorities could achieve a collective solution through binding agreements, shared standards, funding, and accountability. But there is no effective mechanism for making local decisions serve basin-wide, flood-reduction concerns.

Worse, some of the jurisdictions that have responsibility to fix flooding also have conflicting mandates. For instance, Montgomery County Engineering, which would permit the Scarborough Development, answers to the County Judge and Commissioners. Their top priority may be economic growth.

Another example: The Texas General Land Office, which administers $14 billion of Flood Remediation and Mitigation money for the US Department of Housing and Urban Development, has reportedly invested $140 million in developing the Scarborough land – some of the most flood-prone land in the region.

Need for a River-Basin-Wide Flood-Control District

One in five Texans live in a known floodplain … and more than one in four in the San Jacinto River Basin (27%). Nationally, a commonly cited benchmark for people living in floodplains is 10%.

According to the 2024 State Flood Plan, 5.2 million Texans live or work in identified 100-year or 500-year flood-hazard areas. Those areas contain 1.66 million buildings. And those figures would likely grow if all floodplains were mapped using current rainfall statistics.

Clearly, the upcoming state legislature should seriously consider the San Jacinto Regional Flood Planning Group’s recommendations above to consolidate responsibilities for flood management.

State Representative Dennis Paul proposed such legislation previously. But the parochial concerns of local authorities, such as Harris County Commissioner Adrian Garcia, fearful of losing influence and control, killed the bill.

Early voting starts this month. In the meantime, sign the petition protesting Scarborough if you haven’t already done so. One of the region’s most respected hydrologists has said that if the property gets developed, it would be like aiming a firehose at the Kingwood/Humble area.

Posted by Bob Rehak on 10/5/26

3324 Days since Hurricane Harvey

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.