10 Ways Political Fragmentation Can Increase Flood Risk

7/2/26 – Political fragmentation can increase flood risk many ways. It is one of the least appreciated, but most significant factors in flooding – particularly in rapidly urbanizing watersheds like the San Jacinto River Basin.

Floodwater doesn’t respect jurisdictional boundaries. When many different jurisdictions make drainage decisions independently, it rarely, if ever, optimizes results. Here are 10 reasons why.

1. Upstream Communities Often Don’t Bear Downstream Costs They Create

A city or county may approve new development because it receives the tax revenue while the flood impacts occur miles away. For example:

  • Community A approves thousands of acres of development.
  • Runoff increases.
  • The additional water flows into Community B.
  • Community B pays for larger channels, detention basins, buyouts, and disaster recovery.

The economic incentives are misaligned. Individual interest trumps wider interest.

2. Different Regulations Create Weak Links

When designing flood infrastructure, one county may require:

  • Atlas 14 rainfall
  • Generous detention
  • “No net fill” in floodplains
  • Stricter erosion controls.

But a neighboring county may require much less.

Developers naturally gravitate toward the least restrictive jurisdiction.

The result is that runoff is generated where regulation is weakest. But that affects everyone downstream.

This has long been an issue between portions of rapidly growing counties surrounding Houston, where drainage criteria have historically differed.

3. Development is Approved One Project at a Time

Each subdivision may demonstrate “No adverse impact from this development.” And that may be technically true for that individual project. But no one evaluates:

Thousands of individually compliant projects can collectively overwhelm streams.

This is sometimes called the “Death by a Thousand Cuts” problem.

4. Transportation Agencies Optimize Roads – Not Watersheds

Road departments may prioritize:

  • Minimizing bridge costs
  • Minimizing culvert costs
  • Reducing construction expenses.

Flood managers may want:

  • Larger openings under bridges
  • Fewer hydraulic bottlenecks
  • Preservation of natural floodways.

If transportation and flood agencies are not coordinated, roads can become unintended dams during major floods.

East Fork Floods
FM2090 at East Fork on May 1, 2024. The opening for the bridge is in the trees on the upper right.

5. Reservoir Operators May Have Different Missions

Sub-watersheds often include reservoirs managed by different organizations and/or for different purposes. For instance, one reservoir may prioritize water supply while another prioritizes flood control or recreation.

Without coordinated operating plans, releases can unintentionally compound downstream flooding. This has been discussed extensively regarding operations of Lake Conroe and Lake Houston, where coordinated releases can substantially influence downstream flood peaks.

Lake Houston Dam during Harvey
The 400,000 CFS going over the Lake Houston Dam during Harvey included 80,000 CFS from Lake Conroe. It created a wall of water 11 feet high. The volume was five times more than the amount of water going over Niagra Falls on an average day.

6. Funding Responsibilities are Fragmented

One agency may pay for channel improvements, while others pay for maintenance, detention, environmental mitigation, and/or emergency response.

Projects that benefit everyone may stall because no single organization is responsible for paying for them. Coordination among agencies with different staffing, funding, and priorities can delay projects years. Economists call this a “collective action problem.”

For instance, according to Harris County Flood Control District (HCFCD), only half of the Taylor Gully/Woodridge project has started because the Texas Water Development Board has reportedly not yet approved the Taylor Gully portion.

Meanwhile, a critical HUD funding deadline is fast approaching that may cost Harris County hundreds of millions of dollars. It’s an HCFCD project. But City of Houston bridges are involved.

Taylor Gully Flooding May 7 2019
School bus trying to go over Taylor Gully on the Rustling Elms bridge on May 7, 2019.

Aligning all these dominos takes years, especially when they involve grants from multiple agencies.

7. Floodplain Mapping Evolves at Different Speeds

One jurisdiction may adopt updated flood maps quickly while a neighboring jurisdiction may continue using older maps.

This means development can continue under outdated assumptions upstream while downstream communities build to newer, more conservative standards.

Again, the Taylor Gully/Woodridge project provides an excellent example. HCFCD contractors are now excavating dirt for a Woodridge Detention Basin. Some of that dirt is being hauled to a new development along Dry Creek at FM1485 in Montgomery County.

Technically, the dirt is being deposited outside the 100-year floodplain at that location, per HCFCD standards. But the Montgomery County floodplain map is still based on pre-Harvey (2014) data.

Where Woodridge dirt is going. Map last updated in 2014 before Harvey. From FEMA Flood Hazard Layer Viewer.
Placement area for a portion of dirt excavated from Woodridge, shown in red circle above near Dry Creek.

Are we paying to solve a flood problem…or to relocate it?

8. Data are Often Not Shared

As we saw above, jurisdictions frequently use different:

  • Hydraulic models
  • Rainfall assumptions
  • LiDAR vintages
  • Land-use projections
  • Software platforms

When models don’t align across jurisdictional boundaries, flood analyses can become inconsistent.

9. Maintenance Responsibilities are Divided

Who:

  • Removes sediment?
  • Clears fallen trees?
  • Maintains detention ponds?
  • Repairs eroded channels?

If responsibility changes repeatedly across political boundaries, maintenance gaps develop that reduce channel capacity.

10. Emergency Response Becomes Harder

During large floods:

  • Counties
  • Cities
  • Drainage districts
  • River authorities
  • State agencies
  • Federal agencies

…must all coordinate their activities.

If communication is poor, evacuations, road closures, reservoir operations, and recovery efforts become less efficient.

The Cumulative Effect

Political fragmentation doesn’t usually create flooding by itself. Instead, it gradually amplifies flood risk by allowing many small decisions to accumulate or be deferred.

Fragmented decisionWatershed consequence
Different detention rulesMore runoff
Different floodplain rulesMore development in hazardous areas
Independent land-use decisionsHigher peak flows
Separate infrastructure planningHydraulic bottlenecks
Different maintenance standardsReduced conveyance
Independent reservoir operationsPoorer timing of releases
Separate fundingDelayed mitigation projects

Each individual decision may appear reasonable within one jurisdiction. Collectively, they can increase both the frequency and severity of flooding across the river basin.

Why This Matters in the San Jacinto River Basin

The San Jacinto River watershed illustrates many of these challenges. It spans multiple counties and municipalities with varying drainage standards, development regulations, and infrastructure priorities.

Rapid upstream growth can alter runoff patterns that affect downstream communities, such as the Lake Houston Area. Indeed, it affects all of Houston and Harris County.

At the same time, reservoir operations, floodplain management, and mitigation investments are divided among numerous local, regional, state, and federal entities. Coordinating those decisions across jurisdictional boundaries is often as challenging as the engineering itself.

Many watershed professionals therefore advocate managing flood risk at the “watershed scale” rather than at the city or county scale.

That approach emphasizes common hydrologic assumptions, coordinated land-use planning, cumulative-impact analysis, shared data and models, aligned reservoir operations (where feasible), and funding mechanisms that reflect both where runoff is generated and where flood damages occur.

It does not eliminate flooding, but it can substantially reduce the extent to which fragmented governance makes floods worse.

In the 2025 Texas legislature, Representatives Paul, Cunningham, DeAyala, and Swanson authored a bill (HB2068) to expand HCFCD gradually throughout the river basin. However it was left pending in committee after HCFCD Executive Director Tina Petersen and Precinct 2 Commissioner Adrian Garcia testified against it. Let’s hope it can go farther next year with new leaders.

Posted by Bob Rehak on 7/3/2026 with the help of ChatGPT for research.

3230 Days since Hurricane Harvey

First in a Series: How Development Lifecycles Affect Flood Risk

7/1/2026 – Urban development lifecycles follow predictable stages. Those stages help explain why and when flood risk increases. A better understanding of development lifecycles also helps inform efforts to decrease flood risk.

The Urban Land Institute (ULI) bills itself as world’s oldest and largest global network of cross-disciplinary real estate and land-use experts. They do a tremendous amount of research and education, and are widely regarded as thought leaders in their field. I asked ChatGPT to help research their reports, models and market analyses. I pulled the information below from that Chat.

High-Level Development Lifecycle Stages

ULI often describes communities – especially metro submarkets and master-planned communities – as evolving through five stages.

StageDescriptionTypical Characteristics
1. Pioneer (or Emerging)The earliest phase when development first begins in a previously undeveloped or underutilized area.Raw land or agricultural land transitioning to development; infrastructure just beginning; first subdivisions or projects; high perceived risk but high long-term upside.
2. Growth (or Expansion)Rapid development and population increase as the area gains market traction.Strong housing absorption, new commercial development, schools and services appearing, infrastructure expanding, rising land values.
3. Maturity (or Stabilization)The community reaches build-out or near build-out; growth slows and the market stabilizes.Established neighborhoods, stable population, full services and retail, limited vacant land, slower appreciation.
4. Decline (or Obsolescence)Physical or economic aging begins to affect the area; investment slows and competitiveness declines.Aging infrastructure and housing stock, reduced investment, shifting demographics, declining property values or occupancy.
5. Reinvestment / Redevelopment (or Renewal)New capital and planning initiatives revitalize the area, beginning another cycle.Redevelopment projects, adaptive reuse, infill development, infrastructure upgrades, demographic shifts attracting new residents.

Houston-Area Examples

A rough application of this development lifecycle model to the Houston metro area might look like:

  • Pioneer: far-exurban land along new highways such as the Grand Parkway, e.g., early Colony Ridge years.
  • Growth: areas like The Woodlands and Kingwood in the 1990s–2000s or Bridgeland in the 2010s.
  • Maturity: The Woodlands and Kingwood today — largely built out with stable demographics.
  • Decline: older first-ring suburbs with aging retail strips.
  • Redevelopment: Midtown Houston, East Downtown, or repurposed mall sites.

Seven-Stage Model for Evaluating Land Holdings

ULI and many master-planned community developers also use a more granular seven-stage model when evaluating large land holdings. This framework focuses less on sociology and more on capital deployment, entitlements, and absorption of lots/homes.

StageNameWhat HappensKey Indicators
1. Land Banking / AssemblyA developer or investor quietly accumulates large tracts of land years before development begins.Agricultural or timber land; minimal infrastructure; low carrying costs.Large contiguous acreage; speculation on future growth corridors.
2. Entitlement / PlanningRegulatory approvals are obtained. Master plans are designed.Zoning changes, drainage plans, environmental studies, plats, utility agreements.Engineering studies, infrastructure phasing plans, public hearings.
3. Horizontal DevelopmentMajor infrastructure is constructed.Roads, drainage channels, detention ponds, utilities, grading, flood mitigation.High capital expenditure; land converted into finished lots.
4. Builder Entry / Lot SalesHomebuilders begin purchasing lots from the developer.Model homes, marketing campaigns, early home construction.First residential permits; rising lot absorption rates.
5. Absorption / ExpansionRapid population growth and retail follow rooftops.Schools, retail centers, churches, medical offices, parks.Peak lot sales; fastest population growth.
6. Build-Out / StabilizationMost developable land is used; growth slows.Established neighborhoods, full infrastructure, mature landscaping.Stable property values; fewer new phases.
7. Repositioning / RedevelopmentThe community begins a new cycle through infill or redevelopment.Commercial redevelopment, higher density housing, mixed-use projects.Demographic shifts; reinvestment in aging areas.

The highest financial risk occurs during land banking and entitlement (Phases 1 and 2). And the highest profitability occurs during absorption (Phase 5), when land values accelerate.

Development often expands outward from a city center in concentric rings or waves as new highways are built.

Why Development Lifecycles Matter for Floodplain Development

In river basins like the San Jacinto, the newest development wave often occurs:

  • Upstream of existing urbanized areas
  • On cheaper land with more floodplain acreage
  • Before flood infrastructure is fully planned.

That timing mismatch is one reason ULI and hydrologists often warn that:

Exurban development can amplify downstream flooding if watershed-scale planning is absent.

Floodplain Discount Curve

Several ULI case studies reference a recurring phenomenon sometimes referred to as the “floodplain discount curve.” It’s not a formula as much as a market pattern observed when developers acquire large tracts in floodplains.

The idea: land value rises dramatically as uncertainty about development constraints is removed.

Conceptually, it looks like this:

StageLand StatusTypical BuyerRelative Value
1. Raw Floodplain LandAgricultural land, wetlands, sand pits, or timberland; flood risk uncertain.Speculators, long-horizon developers, timber investors.Lowest value
2. Regulatory ClarityFEMA mapping, drainage rules, wetlands delineation clarified.Land funds, institutional investors.Value increases modestly.
3. Entitlements (i.e., Permits) ApprovedDrainage plan accepted; mitigation strategy defined; plats approved.Large developers.Value rises significantly.
4. Infrastructure InstalledRoads, utilities, detention basins built.Homebuilders purchasing finished lots.Major jump in value.
5. Rooftops ArriveHouses, schools, retail appear.Retail developers and long-term investors.Peak land value

A single tract can experience 20×–100× appreciation over the full lifecycle.

Developers often deliberately acquire floodplain property because it carries a risk discount that sophisticated engineering can sometimes overcome. Risks include:

  • Evolving FEMA, HUD and EPA regulations
  • Fill restrictions
  • Wetlands permitting
  • Insurance concerns
  • Political winds

When these risks are resolved, value re-prices rapidly. The biggest value increase usually occurs at the moment regulatory risk disappears, not when the first house is built. Developers sometimes describe this as:

“Entitlements create more value than construction.”

The Scarborough Example

This explains why developers often land bank floodplain property for 10–30 years waiting for infrastructure or regulations to change. The Scarborough land at the confluence of Spring Creek and the San Jacinto West Fork is a good example.

It also explains why turning the Scarborough land into a state park is the best way to protect it from future development.

In future posts, I will explore specifics of how these concepts have affected growth and flood risk in the Lake Houston and surrounding areas.

For the convenience of those reading this on a small screen, here is a printable PDF of the tables above.

Posted by Bob Rehak on 7/1/2026 with grateful appreciation for ULI and ChatGPT

3228 Days since Hurricane Harvey

Excavation Rate of Woodridge Detention Basin Suddenly Increases

6/30/26 – Two days after posting about the slow rate of progress on Harris County Flood Control District’s (HCFCD) Woodridge Detention Basin, the rate suddenly increased. And dramatically! But, will it be enough?

The sudden increase coincided with the start date for HCFCD’s new Executive Director Marcus Stuckett who is under pressure to accelerate operations. Stuckett must beat tight federal deadlines on a number of projects to avoid losing up to $322 million in federal funding.

New Week, New Vibe

When I visited the Woodridge site around 1PM yesterday (Monday, 6/29/26), I saw six dump trucks leaving the site within a half hour. Today, I returned twice. At 9AM, I saw five leave within a half hour. Ditto when I returned around 11. So, the rate has increased to an average of five or six loads per half hour. That’s good news.

Photos Taken 6/30/26

I’m not sure why the rate increased when it did; Stuckett’s starting day may have just been coincidence. Regardless, I’m glad the contractor finally got construction moving. See photos taken this morning.

Woodridge Construction
Woodridge Construction as of 9:19AM on 6/30/26. Note excavator working on new area (middle left).
Woodridge Construction
Loading one of the long-bed trucks takes about three or four minutes. Only one excavator is working.

A truck would pull up to the excavator about every five minutes. At one point, I even witnessed a traffic jam at the site entrance on Woodland Hills.

Woodridge Construction
Traffic jam at site entrance.
Woodridge Construction
Then the dance of heavy equipment continued.

More Improvement Needed…Even with New Rate

Given sampling error, traffic delays related to Loop 494 closure at Northpark, overtime, weather, etc., it’s still not certain whether the new rate of excavation will beat the contractual deadline. Let’s rerun the numbers using this type of dump truck to see if they’re close.

One of these trucks can carry an average of 22 cubic yards per load; that’s more than the type of truck I previously thought they were going to use.

  • The contractor must move a million cubic yards of dirt.
  • 1,000,000 cubic yards ÷ 22 cubic yards/load = 45,455 truckloads.
  • Contract specifies 552 calendar days. But contractor is working only six days per week and 90 days have elapsed already. That leaves 383 work days.
  • 45,455 truckloads ÷ 383 = approximately 120 truckloads per 8-hour day or 15 per hour.

So far this week, I’ve seen them moving 10-12 loads per hour. So they may still come up short.

And I still haven’t seen any activity on the Taylor Gully portion of the project yet; it has the same deadline. And HCFCD construction docs specify that they expect the contractor to work on both phases simultaneously.

Posted by Bob Rehak on 6/30/26

3227 Days since Harvey

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