The book is primarily targeted to flood-project managers and city officials. However, the informative illustrations and easy-to-understand writing make it a useful primer for anyone who wants to become more knowledgeable about flooding.
The World Bank bills the handbook as a “roadmap for conducting an urban flood risk assessment in any city in the world.”
What will the average person get from it? The ability to understand flood professionals, the issues they face, and how they evaluate problems/solutions.
It also made me realize that Harris County’s equity framework, which the county uses to allocate flood-mitigation funds, fails to incorporate many factors recommended by the Department of Homeland Security and others.
Outline of Handbook
The book contains five chapters.
Chapters cover the following sub-topics.
Intro and Chapter 1: Defining Risk
Much of the book has a checklist quality to it. For instance, what should professionals quantify when defining flood risk?
Hazards and their probabilities
Exposure – an inventory of elements and activities affected by hazards, for instance:
The population and its assets such as homes and belongings, private businesses, and industrial assets
Infrastructure such as roads, drinking water, sanitation, drainage, and flood protection infrastructure
Public infrastructure like health care and school facilities
Environmental and cultural assets
Economic activities.
Vulnerability – the degree to which people, property and infrastructure can be adversely affected
Here, for instance, I was surprised to learn that Harris County’s equity framework considered some, but not all of the factors that make areas vulnerable. For instance, it doesn’t really incorporate infrastructure!
Chapter Two: Hazard Assessment
The chapter on Hazard Assessment begins with a list of “boundary conditions” typically used within a flood model.
Five conditions typically include: (1) rainfall, (2) infiltration, (3) flow, (4) water levels and waves, and (5) pumps and flow control structures.
But just measuring rainfall can be difficult depending on the number and types of gages in use. “Most meteorological services only provide daily values (mostly from manual gauges), which provide part of the overall rainfall characteristics. However, the distribution and intensity within a single day are essential,” say the authors.
Automated gages that can measure short (sub-daily) periods are critical in informing regulations that affect the design of infrastructure. Short, high-intensity bursts are a significant factor in urban flooding. However, many areas have gages measured manually once per day. (The Flood Control District’s are all automated.)
As I scanned the text of this chapter, flashbacks from Harvey kept recurring. When I read this sentence, I thought of the Lake Conroe discharge designed to prevent the flooding of Lake Conroe homes. “Discharge rates from control gates normally relate to both upstream and downstream water levels…” [Emphasis added.] Did the dam operators consider downstream water levels at the time? The case is still pending in the courts.
In chapter 2, I also found the most illuminating discussion of differences between 1D, 2D and 3D modeling that I have ever read.
Ditto for a description of Manning’s Coefficient, which is used to estimate the impact of friction on the speed of water, which in turn affects the rate of accumulation and flood height.
Illustration of Mannings Roughness Coefficient and friction’s impact on speed of floodwater.
Trees and buildings create friction for floodwater that slows it down. But concrete and clear-cutting speed it up.
Such information is used to quantify the potential consequences of flooding to homes, businesses, and people across an area.
Chapter 3: Risk Assessment
Chapter 3 focuses on Risk Assessment and lists types of infrastructure that the Department of Homeland Security defines as “critical sectors.”
Again, Harris County’s Equity Framework (used to distribute flood-mitigation funds) considers none of these.
Chapter 4: Interventions
Chapter 4 discusses types of interventions (solutions to flooding). They fall into three main categories.
The chapter then addresses the limitations, applicability, costs, benefits, and environmental/social impacts of each.
It’s too complicated to summarize here. But it’s fascinating to see how flood professionals evaluate the range of options.
Conclusion
The last chapter addresses the business side of flood mitigation, i.e., bidding jobs. I’ll skip that here and close by saying this. Even after studying flooding for six years, I felt lights turning on almost every time I turned a page in this book.
I had a high level understanding of most of the concepts. But this gave me a much fuller understanding. I found myself constantly thinking, “Aha, so that’s how that fits in.”
Social media has been abuzz this week about the Northpark Drive entry to Kingwood. As contractors removed trees from the north side of the road to make room for a detention pond, many people complained.
But it’s important to remember why we’re improving Northpark: to accommodate increased traffic and to create a reliable, all-weather evacuation route. In that regard, the Lake Houston Redevelopment Authority (LHRA) must balance three conflicting needs: flood mitigation, saving trees and cost. Let’s look at how each relates to the objectives.
Reliable, All-Weather Evacuation Route
During Harvey, Hamblen Road, Kingwood Drive and Northpark were all blocked by rising floodwaters. That forced many people to try to snake out of Kingwood through Porter…if they could get there. Many couldn’t.
For decades, we’ve also worried about the possibility of a train disaster that could block off Kingwood’s exits. The longer trains that Union Pacific runs now can block multiple exits simultaneously. The longest trains stretch for more than three miles. And if there were a derailment or toxic spill, it would be difficult getting people to safety.
Raising the elevation of Northpark between Bens Branch and the Kingwood Diversion Ditch eliminates the first problem. And building the bridge over the tracks at 494 eliminates the second.
Finally, widening the road will enable more vehicles to evacuate faster.
Flood-Mitigation Enhancements
All that extra concrete to expand the road, however, reduces rainwater infiltration and increases runoff. To keep the road from flooding, engineers calculated they needed 22 acre feet of stormwater detention capacity near US59.
The solution: build two permanent ponds, one each on the north and south sides of 59 where the groves of trees were. TxDoT already owned the land. So it was available at no cost.
Looking N toward Kroger Center. Clearing for N pond completed. Clearing for S pond (bottom right) begins next week.
Water will permanently fill the ponds, just like those at Kingwood Drive. The difference between the normal water surface elevation and the lip of the ponds will equal 22 acre feet. The size of the ponds will keep that gap at an aesthetically pleasing level.
Looking S. Note the protective fencing around the remaining trees. Additional trees may be stored temporarily in the foreground.
Said another way, the ponds will look like decorative enhancements but serve a vital purpose that few realize.
The outline you see in the photo below will match the perimeter of the pond.
No more trees will be cut for this pond. The area cleared represents the final outline of the pond.
The layout below shows how the ponds should look when completed.
According to Ralph De Leon, project manager, “Enough trees will remain to form a pleasing backdrop for the pond, screen the visually noisy area behind them, and create a good first impression for visitors.”
From 30 feet, you can barely see the shopping center behind the trees. From ground level, it will be completely screened.
It’s important to remember that when KSA revised the Kingwood entries after TxDoT widened 59, many people wanted ponds at Northpark. They complained that KSA was neglecting Northpark compared to Kingwood Drive.
Many trees are being transplanted. But that’s an expensive proposition; the trees have grown since LHRA first prepared estimates two years ago.
“We’ve already identified the trees that will be saved,” De Leon continued. “Some will move to their permanent location immediately. Others will be stored temporarily at staging locations until the road construction gets further along. Then they’ll be moved to their permanent positions.”
The landscape architects, contractor, and LHRA are evaluating each tree individually. Their objective is to save as many as possible. But dollars pose a constraint.
Cost Limitations
De Leon also says “The cost to move each tree is roughly $11,000. We can’t afford to move the truly huge trees. They cost up to $100,000 per tree. And we just don’t have a budget for those.”
Machines like these will move trees that range from 4″ to 17″ in diameter.Photo courtesy of Davey Tree Company.
To maximize aesthetics, the Redevelopment Authority will relocate a mix of trees, such as oaks and pines.
The trees that will move have already been inventoried and tagged.
Update on Water-Line and Utility Conflicts
In my last Northpark post, I pointed out two conflicts holding up construction of the median farther east – one with a water line to a new church near Russell-Palmer Road and a second with CenterPoint.
The City of Houston has agreed to let the Redevelopment Authority’s contractor design a workaround for the water line that interfered with the placement of box culverts. Contractors left a gap big enough for two sections of culvert and a coffer dam to keep dirt from collapsing into the hole.
Because the culvert is tongue-in-groove, contractors also left enough room for a collar. That will allow the two new sections to slide into place. It will also prevent leaks in any gap that remains.
Regarding the CenterPoint gas line running down the center of the ditch at different depths, CenterPoint decided to move the whole line out of the culvert to the south side of the road. Inbound drivers may notice long lengths of welded blue pipe stacked up between Russell-Palmer and Kings Mill. That’s what that is for.
Next Steps
Contractors will start removing trees for the south entry pond at 59 during the week of 9/24/23. Here is the latest revised schedule. Check back often for more updates as they happen.
In northeast Houston, where residents and activists frequently chant “historic disinvestment,” I accidentally stumbled onto a much more likely cause of the frequent flooding than systemic racism. It happened while browsing a GIS database with hundreds of layers containing a broad range of information. The instant I saw it, it unlocked a mystery. Tumblers suddenly aligned that unlocked the mystery. But let’s start this story with accusations that made no sense to me.
Accusations of Systemic Racism Not Supported by Spending Data
Three years ago, I joined the Harris County Community Flood Resilience Task Force. Ever since, I have heard a constant drumbeat of “historic disinvestment” by many members who believe they are victims of systemic racism by Harris County Flood Control District (HCFCD).
They claim that they aren’t getting their fair share of flood-mitigation funds when, in fact, financial analysis reveals the opposite. They get the lion’s share.
LMI vs. Non-LMI flood-mitigation funding through Q3 2021.
Eight watersheds with a majority of low-to-moderate income residents have received almost two thirds of the funding going back to 2000. That’s out of a total of 23 watersheds. The money has flowed to damage – as it should.
Many people, however, don’t believe that. The loudest complaints have come from the Northeast Action Collective. They waged a battle to remove flood-control executives from office who were working tirelessly on their behalf.
Regardless, falsehoods repeated often enough eventually rose to the level of “accepted truth.” Even experts can be fooled. Jim Blackburn, the renowned professor of engineering at Rice, repeated the “historic disinvestment” claim without presenting any proof in a Houston Chronicle story last week.
He claimed residents of Halls and Greens Bayou watersheds weren’t getting their “fair share” of flood mitigation money. In fact, Greens Bayou ranks #2 in terms of money received. Only Brays Bayou has received more.
Spending by Watershed from 2000 through 2023Q1. Source: Harris County Flood Control District via FOIA request.
And tiny Halls Bayou ranks #2 in spending per capita. Together, the two bayous have received more than $390 million to date.
And they could soon receive another $466 million out of the $750 million that the GLO and HUD recently granted Harris County for flood mitigation. If HUD approves the recommended projects totaling $466 million, Halls and Greens will have received $856 million – far more than any other watershed. (Technically Halls is a sub-watershed of Greens, but HCFCD tracks spending as if it were separate.) This is hardly historic disinvestment.
More Likely Cause of Flooding Overlooked by Critics Crying Racism
Today, while learning a new (to me) geographic information system, I randomly clicked on a “wetland” layer. Boom! Guess where the largest concentration of wetlands in Harris County is. The northeast!
Note Lake Houston in the upper right, once home to untold acres of wetlands before the dam was built in the 1950s.
As a reminder of what these wetlands once looked like, see the photos of Emily Murphy who kayaks along the shores of Lake Houston.
Photo Courtesy of Emily Murphy
Regulations discourage building in wetlands for good reasons. Water collects there. The soil is less permeable. They are low, poorly drained, and unstable.
In addition, USGS points out the many positive benefits of wetlands. “Wetlands provide habitat for thousands of species of aquatic and terrestrial plants and animals. Wetlands are valuable for flood protection, water quality improvement, shoreline erosion control, natural products, recreation, and aesthetics.”
But because they’re cheap land and available, some less-than-scrupulous developers often try to build in them. I’m told by engineers I trust that that has always been the case and always will be.
Back in the 1950s, farms and ranches occupied most of the northeast Houston area. Here’s what it looked like then.
Note the San Jacinto River in the upper right in this 1953 pre-Lake Houston aerial image from Google Earth.
And here’s what the same area looks like today.
Note the presence of Lake Houston in the upper right in this 2022 image.
There are still big undeveloped areas in the image above. But many developments have also filled in large parts of the northeast that were once wetlands in the 1950s image.
Dangers of Building Over Wetlands
According to USGS, “Wetlands are transitional areas, sandwiched between permanently flooded deepwater environments and well-drained uplands, where the water table is usually at or near the surface or the land… The single feature that most wetlands share is soil or substrate that is at least periodically saturated with or covered by water.”
Four years ago, I posted about the disadvantages of building over wetlands. Pictures of the Woodridge Village property, then under development by Perry Homes, dramatized how unstable the soils were. Dangers of building over wetlands include shifting slabs, cracked driveways, mold, erosion, clogged storm drains, flooding and more.
Unsuspecting buyers of former wetlands can literally get sucked in by low prices. Seventy years later, the original builders and buyers are long gone. And pre-digital soil samples and drainage analyses (if they were ever done) have long since disappeared into the fog of history or a dusty warehouse.
Wetland-mitigation banks near a development should raise red flags to buyers today. There’s one on the northeast corner of Beltway 8 along, you guessed it, Greens Bayou. There are also two in Colony Ridge: the Houston-Conroe and Tarkington Bayou Mitigation Banks.
In conclusion…
Today’s residents in such areas pay for previous owners’ lack of knowledge – not because of historic disinvestment.
I’m not saying early owners didn’t exercise due diligence. We just didn’t know then what we know now.
Posted by Bob Rehak on 9/22/23
2215 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/2023/09/20230922-Screenshot-2023-09-22-at-12.29.43-PM.jpg?fit=1100%2C717&ssl=17171100adminadmin2023-09-22 17:58:482023-09-22 18:17:41GIS Data Reveals Likely Source of NE Houston Flooding Unrelated to Historic Disinvestment
Review: Urban Flood Risk Handbook
The World Bank recently published the 177-page Urban Flood Risk Handbook: Assessing and Identifying Interventions by Scott Ferguson, Mathijs van Ledden, Steven Rubinyi, Ana Campos, and Tess Doeffinger.
The book is primarily targeted to flood-project managers and city officials. However, the informative illustrations and easy-to-understand writing make it a useful primer for anyone who wants to become more knowledgeable about flooding.
The World Bank bills the handbook as a “roadmap for conducting an urban flood risk assessment in any city in the world.”
What will the average person get from it? The ability to understand flood professionals, the issues they face, and how they evaluate problems/solutions.
It also made me realize that Harris County’s equity framework, which the county uses to allocate flood-mitigation funds, fails to incorporate many factors recommended by the Department of Homeland Security and others.
Outline of Handbook
The book contains five chapters.
Chapters cover the following sub-topics.
Intro and Chapter 1: Defining Risk
Much of the book has a checklist quality to it. For instance, what should professionals quantify when defining flood risk?
Here, for instance, I was surprised to learn that Harris County’s equity framework considered some, but not all of the factors that make areas vulnerable. For instance, it doesn’t really incorporate infrastructure!
Chapter Two: Hazard Assessment
The chapter on Hazard Assessment begins with a list of “boundary conditions” typically used within a flood model.
Five conditions typically include: (1) rainfall, (2) infiltration, (3) flow, (4) water levels and waves, and (5) pumps and flow control structures.
But just measuring rainfall can be difficult depending on the number and types of gages in use. “Most meteorological services only provide daily values (mostly from manual gauges), which provide part of the overall rainfall characteristics. However, the distribution and intensity within a single day are essential,” say the authors.
Automated gages that can measure short (sub-daily) periods are critical in informing regulations that affect the design of infrastructure. Short, high-intensity bursts are a significant factor in urban flooding. However, many areas have gages measured manually once per day. (The Flood Control District’s are all automated.)
As I scanned the text of this chapter, flashbacks from Harvey kept recurring. When I read this sentence, I thought of the Lake Conroe discharge designed to prevent the flooding of Lake Conroe homes. “Discharge rates from control gates normally relate to both upstream and downstream water levels…” [Emphasis added.] Did the dam operators consider downstream water levels at the time? The case is still pending in the courts.
In chapter 2, I also found the most illuminating discussion of differences between 1D, 2D and 3D modeling that I have ever read.
Ditto for a description of Manning’s Coefficient, which is used to estimate the impact of friction on the speed of water, which in turn affects the rate of accumulation and flood height.
Trees and buildings create friction for floodwater that slows it down. But concrete and clear-cutting speed it up.
Such information is used to quantify the potential consequences of flooding to homes, businesses, and people across an area.
Chapter 3: Risk Assessment
Chapter 3 focuses on Risk Assessment and lists types of infrastructure that the Department of Homeland Security defines as “critical sectors.”
Again, Harris County’s Equity Framework (used to distribute flood-mitigation funds) considers none of these.
Chapter 4: Interventions
Chapter 4 discusses types of interventions (solutions to flooding). They fall into three main categories.
The chapter then addresses the limitations, applicability, costs, benefits, and environmental/social impacts of each.
It’s too complicated to summarize here. But it’s fascinating to see how flood professionals evaluate the range of options.
Conclusion
The last chapter addresses the business side of flood mitigation, i.e., bidding jobs. I’ll skip that here and close by saying this. Even after studying flooding for six years, I felt lights turning on almost every time I turned a page in this book.
I had a high level understanding of most of the concepts. But this gave me a much fuller understanding. I found myself constantly thinking, “Aha, so that’s how that fits in.”
And it’s a free download!
Kudos to the World Bank and the authors. They have provided a valuable addition to the literature.
Posted by Bob Rehak on 9/24/23
2217 Days since Hurricane Harvey
Used with permission of World Bank
Northpark Entry Plan Balances Flood Mitigation, Saving Trees, Cost
Social media has been abuzz this week about the Northpark Drive entry to Kingwood. As contractors removed trees from the north side of the road to make room for a detention pond, many people complained.
But it’s important to remember why we’re improving Northpark: to accommodate increased traffic and to create a reliable, all-weather evacuation route. In that regard, the Lake Houston Redevelopment Authority (LHRA) must balance three conflicting needs: flood mitigation, saving trees and cost. Let’s look at how each relates to the objectives.
Reliable, All-Weather Evacuation Route
During Harvey, Hamblen Road, Kingwood Drive and Northpark were all blocked by rising floodwaters. That forced many people to try to snake out of Kingwood through Porter…if they could get there. Many couldn’t.
For decades, we’ve also worried about the possibility of a train disaster that could block off Kingwood’s exits. The longer trains that Union Pacific runs now can block multiple exits simultaneously. The longest trains stretch for more than three miles. And if there were a derailment or toxic spill, it would be difficult getting people to safety.
Raising the elevation of Northpark between Bens Branch and the Kingwood Diversion Ditch eliminates the first problem. And building the bridge over the tracks at 494 eliminates the second.
Finally, widening the road will enable more vehicles to evacuate faster.
Flood-Mitigation Enhancements
All that extra concrete to expand the road, however, reduces rainwater infiltration and increases runoff. To keep the road from flooding, engineers calculated they needed 22 acre feet of stormwater detention capacity near US59.
The solution: build two permanent ponds, one each on the north and south sides of 59 where the groves of trees were. TxDoT already owned the land. So it was available at no cost.
Water will permanently fill the ponds, just like those at Kingwood Drive. The difference between the normal water surface elevation and the lip of the ponds will equal 22 acre feet. The size of the ponds will keep that gap at an aesthetically pleasing level.
Said another way, the ponds will look like decorative enhancements but serve a vital purpose that few realize.
The outline you see in the photo below will match the perimeter of the pond.
The layout below shows how the ponds should look when completed.
Saving Trees
According to Ralph De Leon, project manager, “Enough trees will remain to form a pleasing backdrop for the pond, screen the visually noisy area behind them, and create a good first impression for visitors.”
It’s important to remember that when KSA revised the Kingwood entries after TxDoT widened 59, many people wanted ponds at Northpark. They complained that KSA was neglecting Northpark compared to Kingwood Drive.
Many trees are being transplanted. But that’s an expensive proposition; the trees have grown since LHRA first prepared estimates two years ago.
“We’ve already identified the trees that will be saved,” De Leon continued. “Some will move to their permanent location immediately. Others will be stored temporarily at staging locations until the road construction gets further along. Then they’ll be moved to their permanent positions.”
The landscape architects, contractor, and LHRA are evaluating each tree individually. Their objective is to save as many as possible. But dollars pose a constraint.
Cost Limitations
De Leon also says “The cost to move each tree is roughly $11,000. We can’t afford to move the truly huge trees. They cost up to $100,000 per tree. And we just don’t have a budget for those.”
To maximize aesthetics, the Redevelopment Authority will relocate a mix of trees, such as oaks and pines.
Update on Water-Line and Utility Conflicts
In my last Northpark post, I pointed out two conflicts holding up construction of the median farther east – one with a water line to a new church near Russell-Palmer Road and a second with CenterPoint.
The City of Houston has agreed to let the Redevelopment Authority’s contractor design a workaround for the water line that interfered with the placement of box culverts. Contractors left a gap big enough for two sections of culvert and a coffer dam to keep dirt from collapsing into the hole.
Because the culvert is tongue-in-groove, contractors also left enough room for a collar. That will allow the two new sections to slide into place. It will also prevent leaks in any gap that remains.
Regarding the CenterPoint gas line running down the center of the ditch at different depths, CenterPoint decided to move the whole line out of the culvert to the south side of the road. Inbound drivers may notice long lengths of welded blue pipe stacked up between Russell-Palmer and Kings Mill. That’s what that is for.
Next Steps
Contractors will start removing trees for the south entry pond at 59 during the week of 9/24/23. Here is the latest revised schedule. Check back often for more updates as they happen.
Posted by Bob Rehak on 9/23/23
2216 Days since Hurricane Harvey
GIS Data Reveals Likely Source of NE Houston Flooding Unrelated to Historic Disinvestment
In northeast Houston, where residents and activists frequently chant “historic disinvestment,” I accidentally stumbled onto a much more likely cause of the frequent flooding than systemic racism. It happened while browsing a GIS database with hundreds of layers containing a broad range of information. The instant I saw it, it unlocked a mystery. Tumblers suddenly aligned that unlocked the mystery. But let’s start this story with accusations that made no sense to me.
Accusations of Systemic Racism Not Supported by Spending Data
Three years ago, I joined the Harris County Community Flood Resilience Task Force. Ever since, I have heard a constant drumbeat of “historic disinvestment” by many members who believe they are victims of systemic racism by Harris County Flood Control District (HCFCD).
They claim that they aren’t getting their fair share of flood-mitigation funds when, in fact, financial analysis reveals the opposite. They get the lion’s share.
Eight watersheds with a majority of low-to-moderate income residents have received almost two thirds of the funding going back to 2000. That’s out of a total of 23 watersheds. The money has flowed to damage – as it should.
Many people, however, don’t believe that. The loudest complaints have come from the Northeast Action Collective. They waged a battle to remove flood-control executives from office who were working tirelessly on their behalf.
Regardless, falsehoods repeated often enough eventually rose to the level of “accepted truth.” Even experts can be fooled. Jim Blackburn, the renowned professor of engineering at Rice, repeated the “historic disinvestment” claim without presenting any proof in a Houston Chronicle story last week.
He claimed residents of Halls and Greens Bayou watersheds weren’t getting their “fair share” of flood mitigation money. In fact, Greens Bayou ranks #2 in terms of money received. Only Brays Bayou has received more.
And tiny Halls Bayou ranks #2 in spending per capita. Together, the two bayous have received more than $390 million to date.
And they could soon receive another $466 million out of the $750 million that the GLO and HUD recently granted Harris County for flood mitigation. If HUD approves the recommended projects totaling $466 million, Halls and Greens will have received $856 million – far more than any other watershed. (Technically Halls is a sub-watershed of Greens, but HCFCD tracks spending as if it were separate.) This is hardly historic disinvestment.
More Likely Cause of Flooding Overlooked by Critics Crying Racism
Today, while learning a new (to me) geographic information system, I randomly clicked on a “wetland” layer. Boom! Guess where the largest concentration of wetlands in Harris County is. The northeast!
As a reminder of what these wetlands once looked like, see the photos of Emily Murphy who kayaks along the shores of Lake Houston.
Regulations discourage building in wetlands for good reasons. Water collects there. The soil is less permeable. They are low, poorly drained, and unstable.
In addition, USGS points out the many positive benefits of wetlands. “Wetlands provide habitat for thousands of species of aquatic and terrestrial plants and animals. Wetlands are valuable for flood protection, water quality improvement, shoreline erosion control, natural products, recreation, and aesthetics.”
But because they’re cheap land and available, some less-than-scrupulous developers often try to build in them. I’m told by engineers I trust that that has always been the case and always will be.
Back in the 1950s, farms and ranches occupied most of the northeast Houston area. Here’s what it looked like then.
And here’s what the same area looks like today.
There are still big undeveloped areas in the image above. But many developments have also filled in large parts of the northeast that were once wetlands in the 1950s image.
Dangers of Building Over Wetlands
According to USGS, “Wetlands are transitional areas, sandwiched between permanently flooded deepwater environments and well-drained uplands, where the water table is usually at or near the surface or the land… The single feature that most wetlands share is soil or substrate that is at least periodically saturated with or covered by water.”
Wetlands are almost always terrible places to build houses.
Four years ago, I posted about the disadvantages of building over wetlands. Pictures of the Woodridge Village property, then under development by Perry Homes, dramatized how unstable the soils were. Dangers of building over wetlands include shifting slabs, cracked driveways, mold, erosion, clogged storm drains, flooding and more.
Unsuspecting buyers of former wetlands can literally get sucked in by low prices. Seventy years later, the original builders and buyers are long gone. And pre-digital soil samples and drainage analyses (if they were ever done) have long since disappeared into the fog of history or a dusty warehouse.
Wetland-mitigation banks near a development should raise red flags to buyers today. There’s one on the northeast corner of Beltway 8 along, you guessed it, Greens Bayou. There are also two in Colony Ridge: the Houston-Conroe and Tarkington Bayou Mitigation Banks.
In conclusion…
I’m not saying early owners didn’t exercise due diligence. We just didn’t know then what we know now.
Posted by Bob Rehak on 9/22/23
2215 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.