Academic research into flooding suggests that “Flood protection tends to reduce small floods, but increases the consequences of rare, large floods.” This is one of the central ideas in modern flood-risk management.
It does not mean that flood-control projects are bad. Rather, it describes an unintended sociological feedback loop that can emerge over the long term, if structural protection is not paired with prudent land-use planning.
The concept traces back to the work of Gilbert F. White in 1945 and has been expanded by researchers such as Raymond J. Burby, Gilberto Di Baldassarre, and others. It is commonly referred to as the levee effect or the safe-development paradox. Simply stated, flood-risk-reduction projects can lull people into a false sense of security.
The Basic Mechanism
The process unfolds over decades rather than years. It follows these steps:
Flood protection is built…
Frequent flooding declines…
Confidence increases…
More homes, businesses and infrastructure are built…
Property values rise…
A flood larger than the “design event” (i.e., the 100-year flood) occurs…
Communities experience much greater losses than would have occurred decades earlier.
Structural flood protection often reduces flood frequency. However, it encourages much more development behind the protection, so exposure increases dramatically. Then, when an event exceeds the design capacity, total losses can be much larger than before.
Why This Happens
Here’s an example. Imagine an area that floods every five years.
Initially, only 100 homes might occupy the area because of flood frequency.
A moderate flood might damage 50 homes.
Then, a levee is built to withstand the 100-year flood.
For the next 30 years:
No floods occur.
Confidence grows.
The area now contains:
5,000 homes
Schools
Hospitals
Shopping centers
Utilities.
Then a 500-year flood overtops the levee.
The levee did exactly what it was designed to do for decades. But because so much development accumulated behind it, the rare failure produces vastly greater losses than would have occurred before the levee existed.
That is the paradox.
Example: New Orleans and Katrina
Perhaps the world’s best-known example is New Orleans during Katrina.
For decades, extensive levees reduced frequent flooding. Large areas below sea level became heavily urbanized. And population and infrastructure expanded behind the levee system.
When Hurricane Katrina exceeded parts of the system’s design, multiple levees failed. Approximately 80% of New Orleans flooded. More than 1,800 people died. Economic losses exceeded $100 billion.
Researchers argue that the levees enabled much greater development in areas that remained vulnerable to catastrophic flooding if protection was exceeded.
The Implication for Houston and the San Jacinto Basin
This idea has direct relevance to the Lake Houston Area and the San Jacinto River Basin.
Suppose all the projects proposed after Harvey (additional upstream detention, optimized gate operations on Lake Conroe, channel conveyance improvements, more floodgates for Lake Houston, etc.) are implemented and reduce the probability of flooding from moderate storms.
However, they could create a widespread perception that “This land is now safe.” And that perception could lead to substantial new development in flood-prone portions of the basin over several decades such as the 5,300 acre Scarborough property at the confluence of the West Fork and Spring Creek.
Wetlands on Scarborough property
Exposure increases. Property values increase. Infrastructure becomes more concentrated.
Then, when an event exceeds the protection system — just as Harvey exceeded many historical design assumptions — the total losses may be larger than they otherwise would have been.
This is precisely why many modern flood-risk experts argue that structural protection must be paired with land-use management rather than viewed as a substitute for it. But “land use management” is fightin’ words in Houston.
Breaking the Cycle
The encouraging news is that the research also points to ways to avoid the paradox. The most commonly recommended strategies are:
Preserve portions of the natural floodplain instead of developing every protected acre.
Use regional detention and natural storage to reduce flood peaks.
Educate home buyers about the limits of flood protection.
Require resilient construction (elevated structures, floodproofing) even behind levees or reservoirs.
Manage development at the watershed scale, not just parcel by parcel.
Why This is Especially Relevant to the San Jacinto
This concept is particularly important for the San Jacinto basin because it reframes the objective of the SJRA’s Joint Reservoir Operations Study.
The study’s success should not be measured solely by whether it lowers flood stages by a few inches. It should also include:
Strong warnings about the safe development paradox
Education about design assumptions for flooding, i.e., the height of foundations above the 100-year flood level.
Said another way, the study should discourage development that eventually erases any gains – one of the central themes in contemporary flood-risk research.
Posted by Bob Rehak on 7/5/2026
3232 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2025/11/Scarborough-Wetlands.png?fit=1100%2C661&ssl=16611100adminadmin2026-07-05 17:35:492026-07-05 20:15:43How Flood Protection Can Increase Consequences of Large Floods
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.
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.
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.
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.
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 abovenear 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 decision
Watershed consequence
Different detention rules
More runoff
Different floodplain rules
More development in hazardous areas
Independent land-use decisions
Higher peak flows
Separate infrastructure planning
Hydraulic bottlenecks
Different maintenance standards
Reduced conveyance
Independent reservoir operations
Poorer timing of releases
Separate funding
Delayed 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.
Posted by Bob Rehak on 7/3/2026 with the help of ChatGPT for research.
3230 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2026/07/Dry-Creek-FM1485-Flood-Map-copy.jpg?fit=1100%2C710&ssl=17101100adminadmin2026-07-03 13:33:102026-07-05 22:12:3610 Ways Political Fragmentation Can Increase 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.
Stage
Description
Typical 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.
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.
Stage
Name
What Happens
Key Indicators
1. Land Banking / Assembly
A 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 / Planning
Regulatory approvals are obtained. Master plans are designed.
High capital expenditure; land converted into finished lots.
4. Builder Entry / Lot Sales
Homebuilders begin purchasing lots from the developer.
Model homes, marketing campaigns, early home construction.
First residential permits; rising lot absorption rates.
5. Absorption / Expansion
Rapid population growth and retail follow rooftops.
Schools, retail centers, churches, medical offices, parks.
Peak lot sales; fastest population growth.
6. Build-Out / Stabilization
Most developable land is used; growth slows.
Established neighborhoods, full infrastructure, mature landscaping.
Stable property values; fewer new phases.
7. Repositioning / Redevelopment
The 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:
Stage
Land Status
Typical Buyer
Relative Value
1. Raw Floodplain Land
Agricultural land, wetlands, sand pits, or timberland; flood risk uncertain.
Drainage plan accepted; mitigation strategy defined; plats approved.
Large developers.
Value rises significantly.
4. Infrastructure Installed
Roads, utilities, detention basins built.
Homebuilders purchasing finished lots.
Major jump in value.
5. Rooftops Arrive
Houses, 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 7/1/2026with grateful appreciation for ULI and ChatGPT
3228 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/11/20231112-DJI_0012.jpg?fit=1100%2C733&ssl=17331100adminadmin2026-07-01 13:25:002026-07-05 22:14:01First in a Series: How Development Lifecycles Affect Flood Risk
How Flood Protection Can Increase Consequences of Large Floods
Academic research into flooding suggests that “Flood protection tends to reduce small floods, but increases the consequences of rare, large floods.” This is one of the central ideas in modern flood-risk management.
It does not mean that flood-control projects are bad. Rather, it describes an unintended sociological feedback loop that can emerge over the long term, if structural protection is not paired with prudent land-use planning.
The concept traces back to the work of Gilbert F. White in 1945 and has been expanded by researchers such as Raymond J. Burby, Gilberto Di Baldassarre, and others. It is commonly referred to as the levee effect or the safe-development paradox. Simply stated, flood-risk-reduction projects can lull people into a false sense of security.
The Basic Mechanism
The process unfolds over decades rather than years. It follows these steps:
Structural flood protection often reduces flood frequency. However, it encourages much more development behind the protection, so exposure increases dramatically. Then, when an event exceeds the design capacity, total losses can be much larger than before.
Why This Happens
Here’s an example. Imagine an area that floods every five years.
Initially, only 100 homes might occupy the area because of flood frequency.
For the next 30 years:
Then a 500-year flood overtops the levee.
The levee did exactly what it was designed to do for decades. But because so much development accumulated behind it, the rare failure produces vastly greater losses than would have occurred before the levee existed.
That is the paradox.
Example: New Orleans and Katrina
Perhaps the world’s best-known example is New Orleans during Katrina.
For decades, extensive levees reduced frequent flooding. Large areas below sea level became heavily urbanized. And population and infrastructure expanded behind the levee system.
When Hurricane Katrina exceeded parts of the system’s design, multiple levees failed. Approximately 80% of New Orleans flooded. More than 1,800 people died. Economic losses exceeded $100 billion.
Researchers argue that the levees enabled much greater development in areas that remained vulnerable to catastrophic flooding if protection was exceeded.
The Implication for Houston and the San Jacinto Basin
This idea has direct relevance to the Lake Houston Area and the San Jacinto River Basin.
Suppose all the projects proposed after Harvey (additional upstream detention, optimized gate operations on Lake Conroe, channel conveyance improvements, more floodgates for Lake Houston, etc.) are implemented and reduce the probability of flooding from moderate storms.
However, they could create a widespread perception that “This land is now safe.” And that perception could lead to substantial new development in flood-prone portions of the basin over several decades such as the 5,300 acre Scarborough property at the confluence of the West Fork and Spring Creek.
Exposure increases. Property values increase. Infrastructure becomes more concentrated.
Then, when an event exceeds the protection system — just as Harvey exceeded many historical design assumptions — the total losses may be larger than they otherwise would have been.
This is precisely why many modern flood-risk experts argue that structural protection must be paired with land-use management rather than viewed as a substitute for it. But “land use management” is fightin’ words in Houston.
Breaking the Cycle
The encouraging news is that the research also points to ways to avoid the paradox. The most commonly recommended strategies are:
Why This is Especially Relevant to the San Jacinto
This concept is particularly important for the San Jacinto basin because it reframes the objective of the SJRA’s Joint Reservoir Operations Study.
The study’s success should not be measured solely by whether it lowers flood stages by a few inches. It should also include:
Said another way, the study should discourage development that eventually erases any gains – one of the central themes in contemporary flood-risk research.
Posted by Bob Rehak on 7/5/2026
3232 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.
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:
The economic incentives are misaligned. Individual interest trumps wider interest.
2. Different Regulations Create Weak Links
When designing flood infrastructure, one county may require:
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:
Flood managers may want:
If transportation and flood agencies are not coordinated, roads can become unintended dams during major floods.
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.
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.
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.
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:
When models don’t align across jurisdictional boundaries, flood analyses can become inconsistent.
9. Maintenance Responsibilities are Divided
Who:
If responsibility changes repeatedly across political boundaries, maintenance gaps develop that reduce channel capacity.
10. Emergency Response Becomes Harder
During large floods:
…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.
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.
Houston-Area Examples
A rough application of this development lifecycle model to the Houston metro area might look like:
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.
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:
That timing mismatch is one reason ULI and hydrologists often warn that:
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.
Conceptually, it looks like this:
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:
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:
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