Tag Archive for: Halls Bayou

San Jacinto Flood Planning Group Releases Draft Recommendations

The Texas Water Development Board’s Region 6 San Jacinto Flood Planning Group has released the first draft of its recommendations. You can download the full 295-page Volume One document here (executive summary and all chapters). But the vast majority of the document focuses on methodology and research design. For convenience, I’ve extracted Chapter 5, the 35-pages that discuss recommendations, and summarized them below.

The draft recommendations include:

  • Almost $200 million of additional studies, analysis, models and mapping
  • $27.9 billion in projects.

The projects spread throughout the entire watershed. But here, I’ll focus on those in the northern portion of Harris and the southern portion of Montgomery Counties for brevity.

Halls Bayou

The Flood Planning Group recommends five projects in Halls Bayou totaling $99.65 million, all in collaboration with Harris County Flood Control District (HCFCD). They include:

  • Channel conveyance Improvements on several tributaries
  • Stormwater detention improvements near Hardy West
  • Stormwater detention and channel conveyance improvements along the main stem.

These projects had a positive 1.46 Benefit/Cost Ratio PLUS additional community benefits hard to quantify. They would remove the floodplain from more than 3,000 structures and benefit more than 9,300 people. See pages 5-14 through 5-16.

White Oak Bayou

The Flood Planning Group recommends five channel improvement and detention basin projects for $120 million along White Oak Bayou. The flood planning group determined a benefit/cost ratio of .80 for these projects, meaning costs exceeded benefits. Regardless, they feel there are many community benefits that cannot be quantified. They include removing flood risk from seven miles of roads. See pages 5-15 through 5/18.

Greens Bayou

Greens Bayou would receive $120 million of improvements (construction costs only). They include projects in Fountainview Sections 1 & 2, Castlewood Sections 3 & 4, North Forest, Mid-Reach Greens, Parkland Estates, and Humble Road Place.

A bypass channel under the railroad that parallels US 59 could reduce upstream water surface elevations during extreme events. And a mitigation basin downstream would absorb any adverse impacts in Parkland Estates and Humble Road Place from the bypass channel.

The BCR for all Greens Bayou improvements equals 2.13, meaning benefits double costs. More than 20,000 individuals and 2,000 structures would benefit. See pages 5-18 through 5-20.

San Jacinto River

The Flood Planning Group recommends numerous projects associated with the East and West Forks of the San Jacinto River and their tributaries. It based these recommendations on the San Jacinto River Regional Watershed Master Drainage Plan and a 2018 LiDAR study. See pages 5-21 through 5-31.

Caney Creek

Recommendations include channelizing part of Caney Creek and offsetting that with two dry-dam detention basins: one at FM1097 and the other at SH105. Together, they would store more than 40,000 acre feet of stormwater. That’s enough to hold a foot of stormwater falling across 62.5 square miles! Channelization would occur near the confluence of Caney Creek with the East Fork. That’s near Lake Houston and East End Parks. The projects would remove 42 miles of roadway and 2,422 structures from the 1% annual chance floodplain.

East Fork

A 48-ft tall concrete dam would create a 1.60-mile-long earthen impoundment that captures runoff from Winters Bayou. The dry dam would have five reinforced 10×10 concrete culverts and twin 300′ backup spillways. It would cover almost 2,500 acres and hold 45,000 acre feet of floodwater. That’s enough to hold a foot of stormwater falling over 28.8 square miles.

Lake Creek

Lake Creek would receive some channelization and two dry-dam detention basins holding 37,250 acre feet of storage, enough to hold a foot of stormwater falling over 58 square miles.

Peach Creek

Recommendations also call for partial channelization and two dry-dam detention basins along Peach Creek.

  • The Walker Detention basin would occupy 1,200 acres, hold 36,000 acre feet of stormwater, and cost $200 million.
  • The SH105 Detention basin would occupy 3,000 acres, hold 36,000 acre feet, and cost $400 million.
  • The total 72,000 acre feet of capacity would hold a foot of stormwater falling over 112.5 square miles.
Spring Creek

This project would channelize 15.7 miles of stream at I-45 and through the Woodlands. It would also create two detention basins on Birch and Walnut Creek tributaries to help reduce flood risk downstream. Together, the projects would create more than 35,000 acre feet of floodwater storage capacity, enough to hold a foot of rain falling over 54.8 square miles. The report did not break out the costs.

West Fork

The Flood Planning Group recommends widening and channelizing 5.7 miles of the West Fork near Highway 242. They would create 12,400 acre feet of mitigation storage by widening the river to 750 feet and creating a 2-foot bench above the stream bed. That would involve shaving down the floodplain to 2 feet above the waterline.

Farther downstream, in the Kingwood Area, they would also increase conveyance by widening a 5-mile-long stretch of the West Fork with 3,500-foot wide of benching. This project would require 923 acre-feet of mitigation storage

That would increase total floodwater storage in both locations by 13,423 feet – enough to hold a foot of rain falling across 20.9 square miles.

Is It Enough?

If all these detention basins get built, they could hold a foot of stormwater falling over 337.5 square miles upstream from Kingwood. That’s a lot. In conjunction with other strategies such as dredging and adding more floodgates to the Lake Houston dam, they should help reduce flood risk in the Lake Houston Area … if they aren’t negated elsewhere.

Other portions of the recommendations stress the need for additional strategies. They include but are not limited to:

  • A regional approach to flood mitigation
  • Floodplain preservation
  • Natural solutions
  • Minimum building setbacks
  • More stringent building codes
  • Better drainage regulations
  • Uniform regulations across the watershed
  • Adoption of standards for determining “no adverse impact”

Also note, that these recommendations would take decades to implement and that many would need to be implemented in a specific order. For instance, the State would need to build detention upstream before widening channels downstream. One helps mitigate the other. Without that, you could help people upstream, but hurt people downstream. That flies in the face of HCFCD principles.

To see the locations of all these streams and how much water they conveyed during Harvey, click here.

Posted by Bob Rehak on 8/8/22

1805 Days since Hurricane Harvey

Halls Bayou Has Come a Long Way, But Still Has Long Way to Go

A popular misperception says Halls Bayou has received no flood-mitigation funding. Yet it has received $175 million since 2000. $65 million of that happened since Harvey.

Channel widening, stormwater-detention basins and neighborhood drainage improvements have reduced flood risk somewhat, but several factors – including the need for more funding – make mitigation difficult. HCFCD has many projects still seeking federal assistance.

The Bond Program approved by voters in 2018 includes more than $110 million for the Halls Bayou watershed. That money could help attract another $236 million in federal matching grants for a total of $346 million. But many projects have yet to receive grants and start construction.

Halls cuts diagonally across the northern part of Harris County between Beltway 8 and Loop 610 North. It joins Greens Bayou before the Ship Channel.

From HCFCD.org on 7/24/2022. Halls, a tributary of Greens Bayou, is the darker shaded area.

Background: Halls Ahead

Halls received an extraordinary amount of damage during Tropical Storm Allison in 2001. Among all 23 Harris County watersheds, it ranked second only behind Greens Bayou during that storm. But Greens has four times the area and three times the population. (Greens had 15,590 damaged structures; Halls had 12,820.)

As a result, HCFCD launched many studies of Halls drainage after Allison. They culminated in the 2013 Halls Ahead Plan. But HCFCD lacked money to fully implement it and still does. All unfunded Halls Ahead projects carried forward into the 2018 Bond Program and many were able to start as you will see in the pictures below. Several have even finished. However…

A Phasing Study designated 58 flood risk reduction projects in 12 phases, with estimated costs between $100 million and $150 million per phase. 

Flood Control executives recently traveled to Washington to plead for more help from the Army Corps of Engineers. The Corps now has a pilot program to help economically disadvantaged areas and Halls certainly qualifies. Halls has the highest percentage of vulnerable, Low-to-Moderate Income (LMI) residents of any watershed in Harris County (71%).

Complicating Factors

Blocked roadside ditches trap floodwater in neighborhoods. City of Houston and Harris County Precincts are responsible for roadside ditches, not HCFCD.

Halls is plagued by a combination of factors that make flood mitigation difficult:

  • Silted-in roadside ditches
  • Aging stormwater infrastructure
  • Developments built to older standards
  • Homes frequently built at street level
  • Dense population that leaves little room for mitigation projects
  • Structures built in floodplains that have to be bought out before many mitigation can begin (see below).

Flood History in Halls Watershed

Much of the Halls Bayou watershed developed during or after the 1950s. Take this area immediately east of what became I-45. It was farmland before then.

Google Earth image from 1953.
Halls Bayou 1978
Same area in 1978.
Floodplains today. Cross hatched = Floodway. Aqua = 100-year floodplain. Brown = 500-year. Based on data developed after Allison. Floodplains will expand even farther after new updates.

Homes and businesses built in Halls Bayou floodplains created the flood risk. They also make widening channels or building detention basins difficult because of time-consuming, expensive buyouts.

Vital Stats

These statistics help put Halls Bayou flood problems in perspective. Here’s how Halls ranks among 23 Harris County watersheds on:

  • Watershed size – #16 (42.3 square miles)
  • Population – #10 (152,358 in 2020 census, down 5% from 2010)
  • Population density – #6 (3,602 people/square mile)
  • Dollars per capita in flood mitigation spending – #5 ($1151 per resident)
  • Dollars per square mile – #4 ($3.9 million dollars per square mile between 2000 and the end of last year).
  • Damaged structures – #4 (25,691 structures during five major storms since 2000 [Allison, Tax Day, Memorial Day, Harvey and Imelda])
  • Damage per square mile – #1 (607.4 structures/sq. mi.)

That last point makes recovery difficult for communities, especially less affluent ones. It may help explain the decrease in population.

Allison, Harvey Dramatize Need for Mitigation

HCFCD has documented flooding along Halls 14 times since 1989. But the two worst storms were Allison (2001) and Harvey (2017). Allison damaged 12,820 structures in the watershed. But Harvey damaged fewer – 11,831.

It’s fairly safe to say that without many mitigation improvements made prior to Harvey, Harvey damage would have been worse. However, rainfall distribution patterns make comparisons between the storms difficult.

The following table from HCFCD’s final Harvey report compares rainfall associated with severe, recent storms for various time periods. Tropical Storm Allison exceeds Harvey’s rainfall in the 6, 12 and 24-hr periods. But in the 2-day period, Harvey produced 6.0 inches more than Allison and 8.9 inches more over 4 days.

From HCFCD Final Harvey Report

Photos of Stormwater Detention Projects from 7/19/22 Flyover

Last Tuesday, I flew most of the length of Halls Bayou with two fellow members of the Harris County Community Flood Resilience Task Force, Ken Williams and Bill Callegari. Let’s take a look at several Halls projects already completed or under construction – starting upstream and working east.

Helms Street Basins

East Helms runs between these two small basins just south of Aldine Mail Route Road. HCFCD completed these last year. They hold 119 acre-feet. That’s a little less than 3″ of stormwater falling over a square mile.

Looking NE. Helms Street Stormwater Detention Basins, Phases 1 & 2.

P518-11-00

I last reported on this project in March 2022. It’s still under construction.

The $6 million stormwater detention basin project will provide regional mitigation benefits. 

The basin will hold 180 acre-feet of stormwater. That’s about 3.5 inches of rain falling across a square mile. It will be a wet-bottom basin with a vegetated shelf.

Looking S at new detention basin. Between Halls Bayou at far end and Isom Street in foreground. Aldine Mail Route Road is under the camera position.

This basin is part of a larger mitigation project that will also extend and enlarge a channel north to the Western Homes subdivision along Aldine Mail Route Road.

Keith Weiss Park

One of the hidden gems of Houston is Keith Weiss Park east of Aldine-Westfield Road. The area is really a series of large connected detention basins disguised as a nature park with hike and bike trails, soccer fields, piers and boardwalks. City of Houston owns the park.

The Keith Weiss project removed 1,770,000 cubic yards of soil to create detention basins that hold approximately 963 acre feet of stormwater storage. That’s enough to hold a foot of stormwater falling across 1.5 square miles.

Google Earth shows that excavation started around 2006 and was substantially completed by 2010.

Wide shot looking east from over Aldine-Westfield Road. Halls Bayou flows away from camera. See close-ups of the three detention ponds below.
Western-most basin. Halls Bayou in bottom center.
Center pond. Still looking east toward US 59.
Eastern-most pond.

Channel Improvements

HCFCD is making channel improvements along Halls in many locations. See project C-41. The area below lies between Keith Weiss Park and US59.

Looking SE along Halls toward US59. According to the HCFCD website, channel conveyance improvements and an additional detention basin are still in preliminary engineering.

Bretshire Stormwater Detention Basin

The Bretshire Stormwater Detention Basin on Halls Bayou added approximately 635 acre feet of additional stormwater storage upstream of Jensen Drive at US 59. It holds a foot of stormwater falling across one square mile.

Looking East across Bretshire Stormwater Detention Basin toward US59. The Fiesta store is by 59, left of center. Downtown is out of frame to the right.

A large part of a subdivision had to be bought out before construction of this basin could begin. HCFCD substantially completed this basin in 2015.

Hall Park Basin

HCFCD also had to buy out a large part of a subdivision to build the Hall Park basin on the opposite side of US 59. Flood Control substantially completed this project in 2018.

Looking NE across US 59 toward the Hall Park basin and Halls Bayou.

Hall Park holds 835 acre-feet. That’s enough to hold a foot of water falling across 1.3 square miles.

This project involved relocating a City of Houston sanitary sewer line and removing approximately 1.2 million cubic yards of soil.

This project required many buyouts that took almost a decade to complete. Roads shown inside the basin have been removed.

As part of its Bayou Greenways 2020 project, the nonprofit Houston Parks Board is designing and constructing the Halls Bayou Greenway – which includes a hike and bike trail, landscaping and neighborhood connections – along the southern edge of the stormwater detention basin. The full Halls Bayou Greenway will provide nine miles of publicly accessible open space from Brock Park to Keith Wiess Park.

In many cases, such stormwater detention basins are disguised as parks. So, many people don’t even recognize them as basins.

Hopper and Little York Basins

Slightly east of 59 at Hopper and Little York, HCFCD constructed two smaller basins in 2021 along a tributary of Halls. Together they hold approximately 200 acre feet. That’s about a foot of rain falling over a third of a square mile. Or four inches across a whole square mile.

Looking west toward 59 at Hopper Basin. Halls tributary cuts diagonally through pond in foreground.
Looking S along the same tributary (in shade at left) at Little York basin. Little York runs along the bottom of the frame.

Such projects hold water back during storms until it can be slowly and safely released later when water in the bayou has receded.

Holding Back A Foot of Rain Falling Across Almost 5 Square Miles

Altogether, the detention basins in this post will hold almost a foot of stormwater falling across 5-square miles.

Halls Bayou has many other projects in various stages. For a complete listing, see the HCFCD website. Or review this presentation.

Posted by Bob Rehak on 7/23/2022

1790 Days since Hurricane Harvey

HCFCD Asks for Army Corps Help with Tunnels, Halls Bayou, Addicks/Barker

In June 2022, Harris County Flood Control District (HCFCD) pitched the Army Corps (actually the Assistant Secretary of the Army for Civil Works, referred to as ASA(CW)) for help with three large projects. They included Flood Tunnels; Halls Bayou; and the Addicks and Barker Reservoirs. This leave-behind summarizes the presentation.

Setting the Stage

The presentation begins with a history of the relationship between the Army Corps and HCFCD dating back to 1937. It references past joint projects such as work on the Addicks and Barker Reservoirs; and Brays, White Oak, Little Vince, Cypress, Greens and Sims Bayous.

It also references projects not yet completed such as work on White Oak and Hunting Bayous, and Clear Creek. Finally, it looks forward to future collaboration on Buffalo Bayou, Halls Bayou and a County Wide-Study that “lifts up and empowers our diverse communities to thrive.”

The intro contains graphics that summarize:

  • Damage during Hurricane Harvey
  • Atlas-14 rainfall vs previous estimates
  • Current and Active Army Corps projects
  • A county-wide map of “Recently flooded” (from Harvey) structures overlaid on a social-vulnerability map

The leave-behind then makes three “asks” corresponding with each of the three major projects.

Buffalo Bayou and Tributaries Resiliency Study

The first ask is for help “finding the right solution for Addicks and Barker Reservoirs.” It talks about managing residual risk and liability. Specifically, it asks for support through the completion of the Corps’ Buffalo Bayou and Tributaries Resiliency Study.

It alludes to policies and processes impeding needed progress. Then it says, we must blaze a trail for a new equitable flood risk management paradigm.

An engineer familiar with Buffalo Bayou told me that the study had been cancelled at one time because of a poor Benefit/Cost Ratio. It wasn’t because, as you often hear, that home values were low. It was because land acquisition costs were so high. Possible workarounds: several proposed “innovations” including:

  • Flood tunnels
  • A comprehensive benefits framework that includes more than a strict benefit/cost ratio.
  • “Emphasis on community resiliency, environmental justice, and climate change adaptation.”

The last update of this study on the Corps’ website is from late 2020. The final report has not yet been released. This post from 2020 summarizes the findings of the interim report.

County-Wide Section 203 Study

Section 203 of the Water Resources Development Act was amended to let non-Federal sponsors conduct feasibility studies that serve as the basis for authorization of new water resources projects, such as flood tunnels. But acceptance of the results is at the discretion of the ASA (CW). One objective of the presentation: to get the ASA(CW) to partner Harris County on a County-wide flood risk study.

The county pitched the partnership as:

  • A potential “pilot study for Justice40”
  • Climate change preparedness
  • Empowering vulnerable communities to withstand and recover from flood events.

Justice40 is a Biden initiative, announced within his first few weeks in office. It uses every lever at his disposal “to advance environmental justice and spur economic opportunity for disadvantaged communities. The “40” refers to Biden’s promise to deliver at least 40 percent of the overall benefits from Federal investments in climate and clean energy to disadvantaged communities. One of the priorities: mitigation initiatives that reduce or eliminate the risk of repetitive flooding.

Halls Bayou Section 118 Study

According to the presentation, the Federal government had a project to study flood-risk management on Halls Bayou from 1990 to 2016 when it was “de-authorized.” The county wants to restart it. Section 118 refers to “Pilot programs on the formulation of Corps of Engineers’ projects in … economically disadvantaged communities.”

Harris County wants the Corps to include Halls on its list of ten nationwide pilot studies for such communities. HCFCD points out that Halls has the highest percentage of Low-to-Moderate Income residents of any watershed in the county (71%). Halls has a poverty rate of 28% and a social vulnerability index of 0.85 out of 1.00. Halls also has frequent, severe, repetitive flooding.

At one time, HCFCD cancelled Halls’ Bayou studies because they all came back with Benefit/Cost Ratios below 1.0. That means costs exceeded benefits. HCFCD hopes to restart those in 2022. Section 118 gives the ASA (CW) a way to apply other criteria that compensate for a low BCR in disadvantaged areas.

Posted by Bob Rehak on 7/7/22

1773 Days since Hurricane Harvey

New Halls Bayou Detention Pond Rapidly Nearing Completion

Along Halls Bayou, HCFCD is constructing a large stormwater detention basin and making channel conveyance improvements as part of Bond Project C-25. The detention basin will reduce the risk of flooding by taking in excess stormwater during heavy rain events and then releasing it slowly back to the channel when the threat of flooding has passed.

I first covered this project six months ago when construction began. It’s come a long way since then.

Photos of Detention Basin Taken Saturday 3/5/22

Looking S across Isom Street toward Halls Bayou at far end of detention pond. Photo Taken 3/5/22.
Reverse shot. Looking N from over Halls Bayou. Photo taken 3/5/22.
At the south end of the detention basin, before Halls Bayou comes out of its banks, water will pour over the wide concrete spillway and fill up the pond. As the level of water in Halls falls, water will go back into the bayou through the twin culverts.

Projected Completion Dates

HCFCD expects to complete construction of the stormwater detention basin during spring 2022 and channel conveyance improvements during fall 2022.

The $6 million stormwater detention basin project (P518-11-00) will provide regional mitigation benefits and also mitigate increased stormwater coming from drainage improvements in the Western Homes subdivision along Aldine Mail Route Road.

The basin will hold 180 acre-feet, or nearly 58.7 million gallons, of stormwater that might otherwise flood homes and businesses. It will be a wet-bottom basin with a vegetated shelf.

Channel Improvement Highlights

North of the basin, HCFCD will shift Tributary P118-21-00 west and enlarge it to increase its capacity. Along Aldine Mail Route Road and north of the road, the channel will be extended as a box culvert system to the Western Homes subdivision. The channel will have a 140-foot top width and 15-foot depth.

These projects are part the Watershed-Wide Project Implementation Program for Halls Bayou.

Project Locations

Locations of projects above.
These two projects are just two of a dozen along Halls Bayou.

Regardless, activists in Halls claim they get no support from HCFCD and that places like Kingwood get all the flood bond money. As a consequence, the county administrator is revising the flood bond prioritization framework yet again to favor projects in Halls and other low-to-moderate income watersheds.

Posted by Bob Rehak on 3/5/2022

1649 Days since Hurricane Harvey

How Soon We Forget!

How soon we forget. Hurricane Harvey was just 4.5 years ago. Since then I have documented dozens, if not hundreds of questionable practices that erode margins of flood safety.

It Didn’t Have to Be That Bad

Harvey was the largest rainfall event in the history of North America. However, with better regulations and construction practices, it didn’t have to be as destructive as it was.

  • Lax regulations;
  • Willful blindness;
  • Development and construction practices that pushed the safety envelope;
  • Relentless destruction of forests and wetlands near rivers and streams;
  • And homebuyers who didn’t realize their true flood risk…

…made Harvey’s destruction worse than it otherwise would have been.

No one factor by itself would explain Harvey’s destruction. But put them all together, and it’s like “death of a thousand cuts.”

The sheer volume of material – more than 1,000,000 words on this site – makes it difficult for people to see the big picture sometimes. To put 1,000,000 words into perspective, the average novel contains only about 100,000. So I’m condensing the website into a book that includes the themes below.

No One Wins Arguments with Mother Nature

During an interview with Milan Saunders and his daughter Lori, Milan said, “No one wins arguments with Mother Nature.” How profound! It doesn’t matter how many surveys, studies and engineer stamps you have on your home’s title. If you don’t:

  • Respect the rivers.
  • Give them room to roam.
  • Protect wetlands.
  • Allow plenty of margin for safety…

…you will flood.

Thought courtesy of Milan Saunders, Chairman/CEO of Plains State Bank. That’s his daughter Lori’s house during Harvey.

Understanding the Causes of Flooding

Excess sedimentation is one of them. Sediment pollution is the single most common source of pollution in U.S. waters. Approximately 30% is caused by natural erosion, and the remaining 70% is caused by human activity.

Large islands built up during Harvey blocked both drainage ditches and rivers. Below, you can see a large sand island (top) built up at the confluence of the Kingwood Diversion Ditch where it reaches the San Jacinto West Fork at River Grove Park. This sand bar reached 10-12 feet in height above the waterline and helped back water up into Trailwood, the Barrington and Kingwood Lakes and Kings Forest. Before the Army Corps dredged this island, River Grove flooded five times in six months. It hasn’t flooded since.

The Kingwood Diversion Ditch and West Fork San Jacinto were almost totally blocked by sediment dams deposited during Harvey.

The second photo above was taken a few hundred yards downstream on the West Fork from the first. It shows “Sand Island” – so nicknamed by the Army Corps. It took the Corps months to dredge this island which they say had blocked the West Fork by 90%.

A certain amount of this sedimentation can be explained by natural erosion. But mankind also contributed to the sheer volume by other practices which I will discuss below.

Respect the Rivers

The red polygons in the satellite image below surround 20-square miles of sand mines on the West Fork of the San Jacinto in a 20 mile reach of river between I-45 and I-69. That exposes a mile-wide swath of sediment to erosion during floods and increases the potential for erosion by 33x compared the river’s normal width.

Even without floods, mines sometimes flush their waste into the rivers. The shot below on the top right shows the day the West Fork turned white. The TCEQ found the source of the pollution upstream: a sand mine that had flushed 56 million gallons of sludge into the West Fork (bottom right).

Influence of sand mines of West Fork San Jacinto water quality.

End the War on Wetlands

Wetlands are nature’s detention ponds. During storms, they hold water back so it won’t flood people downstream. But we seem to want to eradicate wetlands. The images below show the Colony Ridge development in Liberty County. Wetlands (right) are being cleared (left) to make way for the world’s largest trailer park. The acceleration of runoff wiped out FM1010 during Harvey. The road still has not been repaired.

Colony Ridge in Liberty County.

Conservation Costs Much Less than Mitigation

Halls Bayou at I-69 near Fiesta. Image on left shows whole subdivisions that that to be bought out before detention ponds on right could be built.

All across Harris County, especially in older areas inside Beltway 8, apartment complexes, homes and businesses are built right next to bayous and channels. This makes it difficult to enlarge streams or build detention ponds when necessary. One study showed that preservation of floodplains is 5X more cost effective than mitigation after homes flood. Yet private developers keep crowding bayous and residents keep demanding public solutions.

Respecting Individuals’ Property Rights While Protecting Others’

In Texas, it sometimes feels that an individual’s right to do what he/she wants with property trumps others’ rights NOT to flood. You may think you’re protected by all those public servants reviewing and approving plans. But what happens when developers and contractors decide to ignore the approved plans? Here’s a prime example: the Laurel Springs RV Resort near Lakewood Cove.

The approved plans said that “Stormwater runoff shall not cross property lines.” So what did the contractors do? They pumped their stormwater over the development’s detention pond wall. When that took too long, they dug a trench through the wall. Then they laid pipes through the wall to permanently empty the sludge into the wetlands of Harris County’s new Edgewater Park.

This apparently violated the developer’s City of Houston permit, the Texas Water Code, TCEQ’s construction permit and the developer’s stormwater pollution prevention plan. Four investigations are currently swirling around this development. The contractor also cut down approximately 50 feet of trees in Edgewater Park along the entire boundary line and received a cease-and-desist letter from the Harris County Attorney. But the damage is done.

Balance Upstream and Downstream Interests

About 10% of all the water coming down the West Fork at the peak of Harvey came from Crystal Creek in Montgomery County. But the wetlands near the headwaters of Crystal Creek are currently under development. And the developer is avoiding building detention ponds with a “beat-the-peak” survey. This loophole allowed by Montgomery County says that if you get your stormwater to the river faster than the peak of a flood arrives, then you’re not adding to the peak of a flood and you don’t have to build detention ponds. So developers conduct timing surveys to reduce costs and maximize salable land.

What happens when upstream areas develop without consideration for the impact on downstream property owners.

Of course, speeding up the flow of water in a flood is the opposite of what you want to do. To reduce flooding, you should hold back as much water as possible.

The slide above shows part of a new development called Madera at SH242 and FM1314 being built on wetlands near Crystal Creek.

The graph on the right shows what happened on Brays Bayou without suitable detention upstream. Floodwaters peak higher, sooner. Harris County has spent more than $700 million in the last 20 years to remediate flooding problems along Brays.

How much will we need to spend when more areas like Madera get built upstream on the West Fork?

How Quickly We Forget!

FEMA’s Base-Flood-Elevation Viewer shows that in that same area, developers have already built homes that could go under 1-5 feet of water in a 100-year flood. These homes are actually in a ten-year flood zone. And yet more homes are being built nearby. On even more marginal land!

In recent years, the price of land as a percent of a new home’s cost has risen from a historical average of 25% to approximately 40% today. This puts pressure on developers to seek out cheaper land in floodplains, reduce costs by avoiding detention pond requirements, pave over wetlands, and reduce lot sizes resulting in more impervious cover. All contribute to flooding.

Of course, smart homebuyers would not make such risky investments. But few lack the expertise to gauge flood risk. Educating such homebuyers will be one of the major objectives of the book I hope to write.

Posted by Bob Rehak on 2/23/2022

1639 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.

Where Flood-Bond Spending Is Going, When New Flood Maps Will Be Released

On the Harris County Commissioner’s Court agenda for today are two Harris County Flood Control District (HCFCD) “transmittals.” One will update commissioners on flood-bond spending to date. The other will update commissioners on the progress of new flood maps (the MAAPnext program). They are items 269 and 270 on today’s agenda.

Transmittals are reports by departments. Commissioners don’t usually discuss them unless one of the commissioners wishes to make comments for some reason. So, I’m calling them to your attention here.

Flood-Mitigation Spending Through Third Quarter Reaches $865 Million

About half of the $865 million spent on flood mitigation since voters passed the bond in 2018 has come from bond funds. The rest has come from grants and local partnerships. See pie chart below on left.

The left pie chart underscores the importance of partnership funding.

The map below shows where flood-bond spending has occurred.

Flood-mitigation spending by watershed since approval of flood-bond in 2018.

The winner in the $weep$take$: HCFCD spent almost $154 million on Brays Bayou.

Other leading watersheds (rounded to nearest million) in flood-bond spending included:

  • $81 million in Addicks Reservoir
  • $76 million on Greens Bayou
  • $76 million on Cypress Creek
  • $50 million on Little Cypress Creek
  • $46 million on White Oak Bayou
  • $32 million on Clear Creek

With a few exceptions, this spending reflects the influence of the Harris County Flood-Bond Equity Prioritization Framework implemented in 2019. That framework gives highest priority to low- to middle-income watersheds with a high social-vulnerability index. Thus, tiny Halls Bayou has received more assistance than the largest watershed in the county – the San Jacinto River. And Brays Bayou has received almost 11 times more assistance than Buffalo Bayou.

Two notable exceptions are:

  • Vince Bayou which is almost totally inside the City of Pasadena and is therefore primarily Pasadena’s responsibility.
  • Little Cypress Creek which is part of HCFCD’s experimental Frontier Program. The Frontier Program aims to prevent future flooding by buying up land on the cheap before it’s developed. HCFCD then sells detention basin capacity to developers to help make back its investment.

Other Insights Gained from Report

  • Most projects are ahead of schedule and on budget. Good news!
  • More than half of buyouts have been completed and enough funding apparently remains to complete the rest.
  • Progress continues on the $124 million FEDERAL Flood Damage Reduction project on White Oak Bayou, where six stormwater detention basins will hold almost a billion gallons of stormwater. That’s equivalent to about a foot of stormwater falling over almost 5 square miles.
  • No actual projects in the Kingwood Area have begun construction yet. However, the Excavation and Removal Project on Woodridge Village could soon begin.

Additional maps in the full report show:

  • Dollars funded to date by watershed (Note, for instance, another $47 million in funding already committed to Brays).
  • Active Maintenance projects
  • Active Capital projects

Also, a massive GANNT chart shows the stages of every project in every watershed and county-wide projects.

Check out the full report here.

Controversy over Previous Version of Report

An earlier version of this report generated some controversy. People in some watersheds didn’t believe the reported expenditures. Members of the Northeast Action Collective questioned whether any projects had started in their watersheds. They demanded immediate cancellation of projects in Kingwood and transfer of Kingwood’s funds, so that projects in Halls and Greens Bayou could start immediately.

That’s, in part, why I wrote “How to Find and Verify Flood-Related Information: Part I.” Flood-mitigation projects are hard to spot from the ground. Construction almost always happens out of sight behind tall fences and dense tree lines. After construction, the projects are often disguised as parks. For those who doubt, I recommend confirming the existence of projects from the air.

I haven’t confirmed every project in the county, but I have spot-checked many. And I have yet to find discrepancies between what HCFCD reports and what I can see from the air.

C-25, a Halls Bayou Detention pond now under construction by HCFCD
C-25, a Halls Bayou Detention pond now under construction by HCFCD. The bayou runs through the trees in the foreground.
flood detention basin
New basin at Hopper and US59 on a tributary of Halls Bayou.
Lauder Detention Basin on Greens Bayou as of 10/12/2021
Lauder Detention Basin on Greens Bayou as of 10/12/2021. Phase One of a two-phase project is nearly complete.
Cutten Road detention basin on Greens Bayou continues its relentless expansion.
Phase 2 Aldine Westfield Basin
Phase 1 of the Greens Bayou Aldine-Westfield Basin on left is complete. Phase 2 on right is now beginning.

For more information that includes watershed spending data before the flood-bond, check out the funding page.

MAAPnext Effort About to Be Turned Over to FEMA

Harris County Flood Control (HCFCD) estimates it has completed 86% of its part of the flood-map updates. HCFCD will deliver drafts of the new maps to FEMA in January for review and kick off a campaign of public meetings at the same time. The public will see draft maps in February. A public comment period of 90 days will follow. And FEMA hopes to release preliminary flood insurance insurance rate maps by mid-year next year.

I have had a peek at the new maps and reports. And I must say, the effort should result in a dramatic leap forward in flood-risk understanding. Individualized reports will inform homeowners of their flood risks from a variety of different sources, including street flooding. The prototype of the website is very user friendly.

After receiving preliminary maps from HCFCD, it typically takes FEMA another 18-24 months to release final, official flood maps. That gives affected property owners time to comment and appeal. The process looks like this.

MAAPnext milestones as of the end of 2021.

Posted by Bob Rehak on 11/30/2021

1554 Days since Hurricane Harvey

Another Massive Detention Pond Going In Next to Halls Bayou

Construction has begun on another massive detention pond along Halls Bayou. It stretches south from Isom Street to the bayou between Chrisman and Aldine-Westfield Roads. It covers approximately 26 acres and when complete will hold 180-acre feet of stormwater to reduce the risk of flooding. This is just one of 11 projects comprising the Halls Implementation Program. Together they have a total current value of $212 million dollars.

Looking NNW across the new detention pond. Construction started in August 2021. HCFCD expects completion by March 2022.

Such basins take in excess stormwater during heavy rain events and then release it slowly back to the channel when the threat of flooding has passed. Part of the basin will have a wet bottom and another part will have a vegetated shelf. Yet another part will go in between Isom and Aldine Mail Route Road, although that portion has not yet begun construction. (See below).

Map on left shows current extent of construction work. Eventually, project will also include channel conveyance improvements (right) for a tributary that will be directed into the new pond.

Harris County Flood Control District (HCFCD) lists the project as C-25 on its website. But the Flood Bond Program ID is P518-11-00. Ultimately, this will become part of a much larger project area that includes P118-21-00. Together, they will improve drainage in a large part of east Aldine.

Each of these projects falls into Commissioner Adrian Garcia’s Precinct 2. The description that accompanies the project in the flood-bond spreadsheet says, “This project could reduce the risk of flooding for over 90 buildings and could reduce the 1% floodplain for over 100 acres.” The HCFCD spreadsheet and website indicate a total cost of more than $14 million.

But keep this in mind. Project C-25 will work in conjunction with two proposed Harris County Engineering Department projects: neighborhood drainage improvements in the Western Homes subdivision and proposed roadway and drainage improvements along Aldine Mail Route Road. The detention capacity in the pond you see here will accommodate drainage improvements in those areas without flooding other areas. Thus, the pond will really help more than 90 structures.

The project shown in these photos is P-518. P-118 is still in preliminary engineering review.

C-25 is a partnership project. HCFCD received an approximately $9.5 million Community Development Block Grant for Disaster Recovery (CDBG-DR) from the US Department of Housing and Urban Development (HUD). Approximately $5.4 million comes from local funding.

Photos of Work to Date

Looking NE from the SE corner of the construction. Halls Bayou, center, runs along the southern edge of the new basin. The detention basin in the top center was developed by TxDoT. Another phase of this project will expand north into those trees in the upper left.
Looking north from over Halls Bayou. A large part of this basin will have a wet bottom, which contractors are beginning to excavate now. Only detention capacity above the permanent waterline counts toward the total of 180 acre feet. So this pond will have a depth of 7-8 feet from the top of bank to the waterline.
Reverse shot looking SE from Isom Street. The TxDoT basin and Keith Weiss Park are in the upper left of this shot.
The scale of the workers in this shot shows the depth of excavation as of 10/13/21.

This HCFCD presentation explains more about the project, a related project (P118-21-00/C-28) and their benefits.

Posted by Bob Rehak on 10/13/2021

1506 Days after Hurricane Harvey

The Future that Houston Envisioned for 1990 … in 1968

1968 … the year that humans first traveled around the moon during the Apollo 8 mission. It was a triumphant time for America and Houston, home of the NASA “Manned Spacecraft Center,” its name at the time. We could do anything, it seemed. And we did.

1968 Plan for 1990

A reader recently sent me a preliminary plan developed in 1968 called Houston 1990. The Honorable Louis Welch was Mayor and Intercontinental Airport was still a year away from opening. And the Houston Planning Commission (which developed the plan) clearly had its eye on supporting future growth. The plan discussed new water sources, transportation corridors, green space, cultural amenities, employment centers, retail centers, housing choices and more.

Not all of ideas became reality. But most did.

Hits and Misses

For instance, the plan talks about an “emerging” office, retail and high-rise residential area near Westheimer and West Loop 610. (The Galleria?) It also mentions an emerging business area near Holcomb and Main (The Medical Center?) It predicted the continued dominance of single-family housing and the need outlying employment centers as Houston expanded so people could continue to live near where they worked.

For older Houstonians, this will be a nostalgic trip on Rocky and Bullwinkle’s “wayback machine.”

For younger Houstonians, it will be a lesson in the value of planning. For instance, future transportation options can be taken off the table if land isn’t set aside early enough and people build homes on it. That’s why it’s interesting to see something that looks like a network of greenbelts where the Grand Parkway is now.

But people also ignored parts of the plan. For instance, the need for flood control. The plan designated wide green spaces around bayous and creeks which were largely undeveloped at the time. They could have been used for detention ponds and channel expansion as development pushed outward.

Reservoirs that Never Happened

The plan also showed large reservoirs.

  • One was immediately west of what is now Kingwood where Spring and Cypress Creeks come together with the San Jacinto West Fork near I-69.
  • Another was west of a tiny town in the hinterlands called Tomball on Spring Creek.
  • A third was on the Brazos River near Richmond and Rosenberg.
  • And the fourth was a sprawling affair north of Lake Houston that took in portions of Peach and Caney Creeks, the San Jacinto East Fork and Luce Bayou.

Not one of these reservoirs was developed. And with few exceptions, none of the land along the bayous was set aside. The land along the rivers and streams became settled. And now those areas flood significantly during heavy rains.

Olive-colored areas represent open spaces recommended as set-asides for recreation, water resources, and flood control. However, little of the land was actually set aside for those purposes. The large green ring around the City is now the Grand Parkway.

Difficulty of Flood Mitigation After Development

The planned lake west of Kingwood is now sand mines and subdivisions. Lake Conroe would be built in 1973, five years later farther upstream. And Kingwood started building out in the early 1970s.

Building flood mitigation projects along these waterways now would be difficult. It often requires buyouts that can take a decade or more. This problem was foreseen. People were already building up to the edge of bayous, as you can see in the enlarged portion of the map below that shows Halls Bayou.

Halls Bayou in 1968. Note the green areas suggested as set-asides for “open space” along the bayou where development was already crowding the stream banks, leaving few options for flood control.

Many outlying areas that were sparsely populated in 1968 would follow the Halls Bayou pattern.

People would demand flood mitigation after, not before development.

However, that can become expensive and controversial as we saw this week in Huffman. Some areas there along Luce Bayou flooded badly during Harvey and Imelda. Harris County Flood Control District commissioned a flood-mitigation study that recommended a construction of bypass channel (see sections 4.1.3 and 4.1.4).

But local opposition developed from homeowners whose property would be affected. They fought the project. Harris County Precinct 2 Commissioner Adrian Garcia killed it in the 8/24/21 Commissioner’s Court meeting, citing local opposition. That left Huffman with no immediate flood-mitigation hopes after three years of study and planning.

For Complete 1968 Study

For a high resolution PDF of the entire 1968 plan and accompanying text, click here. (Caution: 33″x30″, 14 megabyte file. Best viewed on large screen. )

Posted by Bob Rehak on 7/27/2021

1459 Days after Hurricane Harvey

Changes to ReduceFlooding: New “Funding” Page

I have made two major changes to ReduceFlooding.com by adding a new page dedicated to “Funding” and removing the “High Rise” page from the menu.

High-Rise Issue No Longer Topical, Funding Is

Funding is a hot topic at the moment and the high-rise battle is over…at least for now. Even though I removed the high-rise page from the menu, I did not delete it. Historical researchers can still find it by searching for “High Rise.” If the topic becomes active in the future, I will restore it to the menu again.

The Funding Page contains links to every funding post since 2019 when the equity debate first arose and commissioners adopted an “equity prioritization framework.” That framework put projects in low-to-moderate-income watersheds at the front of the line. And now some are trying to cancel projects in affluent watersheds to send more money to low-income watersheds that have already received hundreds of millions of dollars.

Learn Where Your Money is Going

The Funding page is broken into two parts. The left contains a summary of the equity debate and how it has evolved in the last three years. It also contains links to the volumes of data obtained from Harris County via Freedom-of-Information-Act requests, as well as statistical analysis of the data. The right part contains links to every related post published since the equity debate started.

Collecting all information related to funding in one place should make it easy for people to find information about their watersheds and where their money is going.

Please explore and send me feedback. I’m always eager to make ReduceFlooding better. And if you see information in the media that is demonstrably false, please send them to the Funding page to find the real data.

Posted by Bob Rehak on 7/29/2021

1430 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.

HCFCD’s “Frontier Program”: A Collaborative Model for Future Flood Mitigation

Harris County Flood Control District’s (HCFCD) Frontier Program is an effort to avoid the problems of past development in newly developing areas. In the past, making developers solely responsible for flood mitigation on the land they owned likely resulted in small, expensive and suboptimal projects. Often, by the time shortcomings of their efforts became apparent, it was too late to do anything. Sometimes, to make room for effective flood-mitigation projects, whole subdivisions had to be bought out – after years of repetitive flooding. See two images below.

Halls Bayou next to the Fiesta on US59 north in 2002. Note the subdivisions on either side of the freeway and compare this shot to the one below.
To create the detention ponds on either side of the freeway, HCFCD had to buy out entire subdivisions, an effort that took more than a decade. The buyouts took 4-5 times longer than construction of the ponds.

Frontier Program Offers a Different Paradigm

The Frontier Program is an organized effort to plan for regional drainage infrastructure in advance of future land development.

Program managers work with developers and landowners to identify large-scale, mutually beneficial projects for drainage that cost-effectively maximize stormwater mitigation and water quality. Plans also include opportunities for public recreation and open space.

Basically, instead of forcing all the responsibility for floodwater detention onto developers, the developers buy detention capacity from HCFCD. But the detention capacity is in larger, more efficient ponds in optimal locations – large enough to accommodate future growth.

Currently HCFCD district has frontier programs operating in two watersheds: Little Cypress Creek and Langham Creek, both in northwest Harris County.

Little Cypress Creek Frontier Program

Little Cypress Creek’s watershed is 52-square-miles, but it has fewer than 30,000 residents. However, Little Cypress Creek is experiencing rapid development with construction of the Grand Parkway and lacks sufficient natural drainage to accommodate expected growth.

Little Cypress Creek Watershed

The Little Cypress Creek Frontier Program includes nine stormwater detention basins and stormwater conveyance improvements along the creek and its tributaries. The detention basins will hold more than 20,000 acre feet of stormwater. Together with conveyance improvements, flooding should be reduced 5-7 feet. This video, featuring Alan Black, HCFCD’s new acting director who lives in the area, explains how the collaborative effort with developers works.

The 2018 flood-bond funded the watershed’s Master Drainage Plan, as well as stormwater conveyance improvements on Little Cypress Creek from Cypress Rosehill to the confluence with Cypress Creek.

This innovative approach is in contrast to typical efforts in which individual land owners and developers install drainage infrastructure that serves their sites alone, resulting in smaller, isolated stormwater detention basins and minimum-width channels for stormwater management. By taking a regional approach, the Frontier Program protects existing developments and provides proper drainage for newly developing properties. 

Developers participate in the Frontier Program by paying a $4,000-per-acre fee to develop in the watershed service area. Developers also participate by excavating a portion of regional drainage facilities and by dedicating property for right-of-way. The Little Cypress Creek Frontier Program will use impact fees primarily to acquire additional right-of-way along the channel and for stormwater detention basins. 

Bottom line: the program calls for stricter stormwater detention requirements to mitigate runoff from new developments.

Upper Langham Creek Frontier Program

HCFCD operates another Frontier Program on Upper Langham Creek in its 16 square-mile watershed.

Major elements include, but are not limited to: 

  • The 190-acre Greenhouse Stormwater Detention Basin in Harris County Precinct 3. The basin ultimately will provide approximately 860 acre-feet of detention storage. 
  • Another 865-acre basin site at Precinct 3’s John Paul’s Landing Park. It will provide 2,360 acre-feet of detention storage.
  • A six-mile, 700-foot-wide, 14-foot-deep floodplain and stream corridor encompassing Langham Creek between the two basins. The variable-width, undulating corridor design features wide flood terraces (or benches), gentle side slopes and in-line detention storage volume for the mitigation of stormwater flows. Within the corridor, Langham Creek will be redesigned as a natural stable stream, with adjacent forested borders, native grasses, and stormwater quality mitigation features.
Here, developers pay a per-acre impact fee of $3,100.

Pay Now or Pay Later

Some residents have complained about spending HCFCD funds in areas where people do not yet live when they flood now.

But this is truly a case of “You can pay me now or pay me later.” And if you pay later, the cost is almost certain to be exponentially higher and take much longer…after a lot of heartbreak, misery and human suffering.

Analogy: think about a doctor who’s so busy dealing with critical care, she has no time to deal with preventive care.

Posted by Bob Rehak on 7/13/2021

1414 Days since Hurricane Harvey