Tag Archive for: Harris County Flood Control

Forest Cove Townhomes: One Down, Two to Go

On 7/5/2022, demolition began on the first of three townhome complexes remaining on Marina Drive in Forest Cove. The complexes had been damaged beyond repair when 240,000 cubic feet per second of stormwater roared through them during Hurricane Harvey.

Since then, the abandoned properties had become magnets for drug dealing, arsonists, and illegal dumping. But the buyout process stalled when owners of some of the units could not be found. The county had to exercise its powers of eminent domain on those by declaring the purchase of several units a “public necessity.”

Now, with legalities out of the way, demolition began at 4:45 Tuesday afternoon. You could almost hear a collective sigh of relief from Forest Cove residents. Removal of the eyesores will restore the community’s image while eliminating a public safety hazard.

Photos of Demolition

Here are some pictures taken between 7/5 and 7/9/22. All that’s left of the first complex is a shrinking pile of rubble, some twisted girders, and some driveway.

Forest Cove Townhome Demolition
Beginning of Forest Cove Townhome Demolition on 7/5/22
By end of second day, 7/6/2022, half of first complex was down, but most of rubble remained.
By end of third day, 7/7/2022, entire first complex was down. Contractors compacted rubble to make it easier to haul it away.
They also separated girders from the rubble. This EPA article describes recycling opportunities for demolition waste.
End of fourth day, 7/9/22. Most of waste was hauled away. Practically nothing remains of first building. Second complex in background will come down next week.
Pile of twisted girders. Remnants of a once proud townhome complex and a laid-back river lifestyle. Next up for demo: the building in background.

Next Steps

The next steps:

  • Demolish building in photo above 7/14/22.
  • Schedule demo of third building as soon as last buyout is completed.

Kudos to Harris County Flood Control and its contractors. This is not easy work when the temperature soars into triple digits. Their efforts will make a huge difference to the community.

Posted by Bob Rehak on 7/10/2022

1776 Days since Hurricane Harvey

TWDB grants HCFCD $2,208,906 to Expand Lauder Basin

Last month, the Texas Water Development Board (TWDB) approved a $2,208,906 grant from the State’s Flood Infrastructure Fund (FIF) to the Harris County Flood Control District (HCFCD) for expansion of the Lauder Stormwater Detention Basin.

The detention basin will eventually hold 1,260 acre-feet of stormwater in Aldine along Greens Bayou. The project will help reduce repetitive flooding in that area. It is one of dozens of such projects under construction in the watershed.

Map showing phases and location of Lauder basin.

The 86th Texas Legislature created the Flood Infrastructure Fund with voter approval through a constitutional amendment in 2019. The fund helps develop drainage, flood mitigation, and flood control projects. State Senator Brandon Creighton sponsored the bill that created the fund.

About Phase 2 of Lauder Project

This particular TWDB grant will help enable Phase 2 of the Lauder Stormwater Detention Basin project (Bond ID C-34).

“We are extremely thankful for this funding and for the support of the Texas Water Development Board to improve flood resilience for residents in the Greens Bayou Watershed,” said Tina Petersen, Harris County Flood Control District Executive Director.

HCFCD finished Phase 1 of the Lauder Stormwater Detention Basin project in the fall of 2021. Phase 2 will provide additional stormwater detention in the former Castlewood development. Homes built there have been bought out.

HCFCD estimates the total cost of Phase 2 will be approximately $20.5 million. The additional capacity in Phase 2 will hold excess stormwater during heavy rain events and then release it slowly back to the channel when the threat of flooding has passed.

Phase 2 will be broken into two compartments.

  • Compartment 1 will bid later this month. Construction will start later this year and finish in 2024.
  • Compartment 2 (which TWDB is funding) is currently will be in design until 2023. Construction will begin in April 2024 and complete in early 2025.

Photos of Areas Involved

Phase 1 included a wet-bottom stormwater detention basin, with a permanent pool and features designed to improve stormwater quality.

Lauder Detention Basin on Greens Bayou as of 10/12/2021
Lauder Detention Basin Phase 1 on Greens Bayou (right) as of 10/12/2021. Looking SSW toward Lauder Road.

Phase 2 will be a dry-bottom stormwater detention basin with opportunities for recreational development by other entities. It will be in the wooded area (top center) of the photo below.

Lauder
HCFCD will construct Phase 2 of the HCFCD Lauder Detention Basin in the wooded area (top center) along Greens Bayou (upper right). Looking northwest toward Greenspoint area.

Garcia Lauds Lauder Progress

“Reducing chronic flooding has been my main priority since taking office. This Lauder Stormwater Detention Basin project represents the kind of progress residents expect and need to see, and we are grateful for the Texas Water Development Board’s support in making this critical project possible,” said Harris County Precinct 2 Commissioner Adrian Garcia. 

“Making Harris County businesses and homeowners safer from flood events requires a commitment to make smart investments, like the TWDB’s. If we want to see our community thrive, we have to ensure families and companies can confidently grow in areas where their businesses and homes are free from flood fears,” he continued.

Relief from Repetitive Flooding

TWDB Chairwoman Brooke Paup said, “We’re proud to provide grant funding for this much-needed project, which has been a team effort, and to partner with our good friends at the Harris County Flood Control District. The TWDB works diligently to help communities across the state, but it’s especially fulfilling to be a partner in helping an area see some relief after experiencing repetitive flooding.”

Absorbs a Foot of Rain Falling Over 2 Square Miles

The two basin phases will hold at least 1,260 acre-feet, or 391 million gallons, of excess stormwater that might otherwise flood homes and businesses.

To visualize an acre foot, think of a football field with a foot of water on it. Now imagine that water extending upwards 1260 feet!

Another way to think about that is to visualize water spreading out horizontally. 1260 acre feet would would be a little less than two square miles. (A square mile comprises 640 acres.) So the two basins would hold a foot of rain falling over two square miles!

Looking at the Atlas 14 Rainfall Probability table below, the two phases would hold a 24-hour, 25-year rain falling over 2 square miles.

atlas 14 rainfall probabilities
Atlas 14 rainfall probabilities for northern Harris County

Flood-Risk Reduction Status

But the service area for the basins is bigger than 2 square miles. So the ponds won’t be enough by themselves to provide protection in a 25-year flood. That’s when other Greens Bayou projects will help. Together, the projects in the Greens Bayou Mid-Reach Program, when all are complete, should protect residents in a ten-year rain. See 10-year column in table above.

The two phases of the Lauder basin by themselves should reduce the risk of flooding for more than 4,500 structures in the 100-year floodplain. Learn more about the Lauder Basin at www.hcfcd.org/C34.

Overall, the flood bond allocated $280 million for Greens Bayou improvements. So far, HCFCD has spent $104 million in bond funds on those projects. So 63% the planned budget remains.

Posted by Bob Rehak on 5/10/22

1715 Days since Hurricane Harvey

Despite Heavy Weekend Rains, Most Area Channels and Streams Stayed Within Banks

Despite heavy weekend rains, with a few exceptions, streams and channels stayed within their banks. There are several possible explanations.

  • Soil was dry before the rains.
  • Rainfall came in two waves separated by several hours, allowing the first peak to start working its way through the system before the second hit.
  • The amount of rainfall was within the designed capacity of most channels.
  • The heaviest storms occurred under relatively narrow bands of training supercells.
  • Harris County Flood Control has been actively working on channels!

Rainfall Map of Heavy Weekend Rains

In the image below, note how much higher the rainfall totals are near the red line compared to areas farther away. Most upstream areas received less than an inch or two, limiting the amount that traveled downstream.

Red line indicated path of supercells that tracked across the center of the county last weekend. Note how highest rainfall totals parallel line.

Heavy But Not Harvey

If you were under one of those supercells, you probably received 5-8 inches of rain between Saturday afternoon and Sunday morning – a little more than a 12-hour time span. Consulting NOAA’s Atlas-14 Rainfall Probability table for this area, you can see that those totals correspond to 2- to 10-year storms. Heavy! But not Harvey!

atlas 14 rainfall probabilities
NOAA’s Atlas-14 rainfall probabilities for the Lake Houston Area

Storms Tracked Perpendicular to Most Watersheds

In Harris County most watersheds track from NW to SE. But the storms tracked perpendicular to that. That limited the amount of water dumped in most watersheds. It might have been very different had the storms tracked parallel with bayous.

Here was the channel status report from Harris County Flood Control on Sunday shortly after noon. It shows that virtually all channels were well within their banks. Only the gage at Luce Bayou and SH321 in Liberty County indicated flooding was a possibility near Lake Houston (warning triangle in upper right).

Despite receiving the highest rainfall total in the area (8.56 inches)…

…Luce Bayou never did come out of its banks at that location. See below. As of today, Luce is falling.

Halls Bayou near 45 briefly came out of its banks, but no structures were reported flooded. Same for Greens Bayou at 59. Water briefly got up to the feeder road there.

Brickhouse Gully, White Oak and Buffalo Bayous were also briefly in danger of coming out of banks in places, but receded quickly according to a HCFCD source. They were all back in banks before I could get there with a camera.

Photos of Area Streams and Bayous

At the East Fork and FM1485, I found a high water caution sign on the road Sunday afternoon. But again, the river was well within its banks. The closest it came to flooding was 2 feet from the top of bank three hours before I took this photo.

Here’s how some other local streams and channels fared in the heavy weekend rains.

A tributary channel of Bens Branch between Woodridge Forest and Northpark Drive next to Kingwood Park High School. That cleared area is the new Preserve at Woodridge that will offer 660 SF homes.
Bens Branch looking E (downstream toward Woodland Hills Drive. CVS on Northpark Drive (left). This was the highest part of the highest stream I found. Notice how it’s almost coming out on the left.
St. Martha’s School Parking lot flooded again a little farther downstream on Bens Branch.
Looking west at Bens Branch toward West Lake Houston Parkway. Note debris line on the left bank in the sun.
The debris line in Taylor Gully shows water never got more than halfway up the bank. Looking upstream from the Maple Bend bridge.
Kingwood Diversion Ditch north of Walnut Lane in distance just hours after tornado ripped through area.
Confluence of East Fork San Jacinto (right) and Caney Creek (left). Note docks still above water on right.

No Reports of Flooded Structures in Harris County

As of 8 PM Monday, Harris County Flood Control had not received any reports of structures flooding from the heavy weekend rains.

Storms of this magnitude are common in Houston, but not for January. Jeff Lindner, Harris County’s meteorologist remembered two in the last decade.

“We had comparable totals on 1-9-2012 in the Brays Bayou watershed (6.6 inches peak in 12 hours). On 1-18-2017, we also had several 4-7 inch gage readings on Brays and 7.0 inches in 12 hours on Lower White Oak Bayou.”

For now, most Harris County residents can chalk this one up in the “close-call” column. But let’s remember that people in Plum Grove DID flood. And pray for the tornado victims in Humble, Kingwood and Forest Cove.

Posted by Bob Rehak on 1/10/2021

1595 Days since Hurricane Harvey

Willow Creek Widening and Stormwater Detention Basins Improving Tomball Drainage

Harris County Flood Control District (HCFCD) has a large active construction project underway in Tomball. Phase I of the project stretches about two-thirds of a mile from SH249 to FM2920 on a tributary of Willow Creek as it arcs around a major shopping center near downtown Tomball and Lone Star College/Tomball. The project includes channel widening and deepening; dry and wet stormwater detention basins; and opportunities for recreational trails.

Limits of Phase 1 are within red oval. Additional improvements (M124-00-00-E002) will extend further south to Willow Creek itself as additional money becomes available.

Willow Creek: A Study in Contrasts

The Willow Creek watershed is located in northwest Harris County. It drains about half of the City of Tomball. The tributary highlighted above flows through densely developed shopping and medical center areas on the northern end to agricultural and oil and gas interests on the lower end.

Looking SW at southern limit of construction toward agricultural and rural areas beyond. FM2920 leads into distance.
Looking NE in opposite direction toward area of channel widening and detention basins. SH249 cuts left to right across top of frame. FM2920 cuts through upper right corner. Tomball in upper right.
HCFCD contractors were hard at work on Christmas Eve afternoon when I took these shots.
Closer shot of detention ponds north of shopping center out of frame on the right.

Willow Creek: Present and Future

Willow Creek flows into Spring Creek just upstream of where Spring Creek crosses under I-45. The Willow Creek watershed covers about 54 square miles. The downstream end of the watershed is within the floodplain of Spring Creek.

Willow Creek Watershed and current HCFCD projects in various stages of completion. This post is about the one near the top center of the frame ending in E001.

Willow Creek watershed is mostly undeveloped. Significant development is limited to the City of Tomball and a few residential subdivisions in the lower end. The development rate has not been very rapid. However, officials expect it to increase as the City of Tomball continues to expand and urbanization from Houston stretches northwest.

This project will directly benefit mostly areas on the northwest side of the county. However, it may provide some downstream benefit by holding back water in major floods.

Goal: Contain Runoff from 100-Year Event

Phase 1 of this project began construction activities in January 2021. As funding becomes available, future phases of the M124-00-00 project will continue channel conveyance improvements and construct several more stormwater detention basins from F.M. 2920 to the confluence with Willow Creek. Phase II will also deepen the channel improvements from Phase 1 that you see above.

The overall goal of the M124-00-00 project is to enable the channel to contain the 1-percent (100-year) storm event within the channel banks based on existing watershed conditions.

HCFCD

The total project focuses on conveyance improvements of stormwater in the area, as well as reducing flood risk through construction of stormwater detention basins. Stormwater detention basins reduce flooding risks by taking in and temporarily storing stormwater during heavy rain events and releasing the water back into the waterways when the threat of flooding has passed.

Multiple new detention basins along the M124-00-00 channel will add approximately 390 million gallons of storage capacity (an approximate 2,164 percent increase in current storage capacity) to benefit the Willow Creek watershed. That’s enough to contain a foot of water falling on 1200 acres.

Posted by Bob Rehak on 12/26/2021 based on info from HCFCD.org

1579 Days since Hurricane Harvey

How Stormwater Detention Basins Work

Stormwater detention basins work by storing excess stormwater temporarily until channels can safely carry it away. Water enters the basin quickly during heavy downpours. But the basin releases it slowly at a steady rate that channels are designed to carry. This helps reduce the risk of flooding.

Harris County is so flat that dams are not often options. Therefore, virtually all of our stormwater storage has to be excavated.

Harris County Flood Control District

Willow Water Hole Example

The Harris County Flood Control District (HCFCD) detention basins typically cover several hundred acres and service regions. Willow Water Hole just outside the southwest corner of Loop 610 on a tributary of Brays Bayou is an excellent example.

The 279-acre Willow Waterhole has six compartments. Willow is part of the Brays Bayou Federal Flood Damage Reduction Project (Project Brays), a multi-year, $550 million project that substantially reduces flooding risk in the Brays Bayou watershed. The project is a cooperative effort between the Harris County Flood Control District and the U.S. Army Corps of Engineers. 

Willow Waterhole Detention Basin Complex in SW Houston has six compartments.

Why the Need?

As areas develop, buildings and concrete cover up soil, so stormwater can’t sink into the ground. Water runs off concrete faster than it does from native grasslands. When that water all hits channels, streams and bayous simultaneously from different directions, it exceeds the carrying capacity of the channel. And homes flood.

Many, but not all, new developments use stormwater detention basins to offset that negative effect.

When full, detention basins often resemble lakes. When dry, detention basins look like large excavated open space areas. The Willow Water Hole is normally dry. Yesterday, however, it contained water from recent rains and the low (seasonal rate of evaporation).

Two of the compartments bracket South Willow Drive. See location above.
Note the weir (discussed below) leading to the channel.

Some systems have water in them permanently, so they resemble small lakes. These provide flood storage between the normal surface of the lake and the top of the bank. See the difference in the photograph below.

Willow Water Hole southwestern pond. Note extra capacity between the top of the water and the top of the banks.

Detention? Retention? Which is It?

A detention basin normally has a dry bottom. It holds excess stormwater temporarily.

A retention basin always has a wet bottom. It stores water indefinitely. Retention basis normally have no outlet. Evaporation and infiltration usually keep the lake levels manageable.

The Harris County Flood Control District always builds and uses detention basins. Developers more likely will use retention ponds and market the resulting “lakes” as residential amenities.

HCFCD owns approximately 70 large regional detention basin sites throughout Harris County. They supplement hundreds of smaller developer-built basins. Countywide, these basins hold billions of gallons of stormwater during heavy rainstorms. 

Two northeastern retention ponds within Willow Water Hole complex on either side of South Post Oak Road.

How Water Gets In

Sometimes HCFCD designs stormwater detention basins with a weir (visible in the first and second drone photos above). The weir, or low dam, lets stormwater rising in the channel spill into the detention basin when it reaches a certain height. Other detention basins have no weirs. They are simply open to a channel. In this case, stormwater fills the basin as it rises in the channel.

But there’s also a third alternative for stormwater detention basins, i.e., those not near a channel. Storm sewers and/or sheet flow fill these detention basins. “Big pipes in – little pipes out” is the rule in this instance. The basin gets the water away from streets and homes quickly. Then lets it drain off slowly.

How Water Gets Out

HCFCD typically designs detention basins to drain by gravity, as opposed to using pumps. This lets basins function when power goes out, a frequent occurrence during floods.

In ponds that drain by gravity, depth of the drain (outfall) is dictated by the depth of the receiving channel. The rate at which stormwater drains depends on the stormwater level in the receiving channel. Typically, stormwater drains out of the detention basin after channel levels recede.

Complex engineering calculations determine the volume of stormwater that a detention basin must hold to protect surrounding homes and businesses. That volume, usually measured in acre-feet, determines the width, length and depth of a basin. The amount of time stormwater stays in a basin depends on levels in the receiving channel and how full the basin got. In Harris County, detention time is usually measured in hours, not days.

How the Process Works

Normal Flow

When there is normal flow in a bayou or channel, the detention basin is generally empty.

Initial Storm Effects

Basins begin to fill as bayous or channels rise, or as surrounding developments drain into them through storm sewers.

Capturing the Flow of a Heavy Storm

As water continues to fill the detention basin, it spreads out into the excavated area. Often culverts connect multiple “compartments” within a larger basin, as above.

Detaining the Flow

By holding water in the detention basin, it does not flood homes and businesses downstream.

Draining Detained Water

As the level of the channel recedes, the channel water level drops and lets the basin drain, but only as fast as the channel can handle it.

Back to Normal Flow

With the water level in the channel normal, the basin is once again empty and ready for the next rainstorm.

End Result

Often, HCFCD partners with local groups, such as the Houston Parks Board, to build trails around these ponds that provide a retreat from busy city life. Areas such as Willow Water Hole also provide habitat for birds. People out for a stroll or a jog may think they are in a beautiful park and not even realize the role it plays in reducing flood risk.

Posted by Bob Rehak on 12/2/2021 based on information provided by HCFCD

1556 Days since Hurricane Harvey

TWDB To Vote on Accepting $63.6 million in FEMA Flood Mitigation Assistance Grants

In its October 7, 2021, board meeting, Texas Water Development Board members will vote on whether to accept $63.6 million in FEMA Flood Mitigation Assistance Grants. The federal funding comes with some strings attached: a $10.23 million local match.

For this round of funding, the TWDB selected 19 sub-applications from local government entities. After screening, FEMA eliminated 6 and identified 13 “for further review.”

Here’s a summary from the TWDB of what they will vote on.

From TWDB Agenda for October 7, 2021

What are Flood Mitigation Assistance Grants?

FEMA’s Flood Mitigation Assistance Program provides competitive grants to local governments for projects that reduce or eliminate the risk of repetitive flood damage to buildings insured by the National Flood Insurance Program.

FEMA chooses recipients in part based on cost-effectiveness (benefit/cost ratio).

Often, local governments, such as cities or counties, bundle individual applications as MoCo did to buy out Tammy and Ronnie Gunnel’s home and dozens of others as we saw in yesterday’s post. That home flooded 13 times in 11 years and cost NFIP at least three quarters of a million dollars.

In a sense, most of these grants are designed to cut FEMA’s losses.

Summary of Each Local Application

Attachment B to the agenda gives a rundown on each of the projects under consideration. See below.

Harris County Drainage Project in Bear Creek Village

Bear Creek Village is located on the west side of the Addicks reservoir near Highway 6. This is an $11.3 million project of which the federal government would pay $8.5 million.

The Harris County project would mitigate 1,421 structures. The current storm sewer system is designed for a 3-year event and is inadequate to collect and drain extreme event runoff. The proposed drainage improvements are intended to provide an additional flow path, so that excess storm water is contained within street right-of-way to an outfall. The project will incorporate a combination of channel construction, street regrading, and enhancement of outfalls. The project has a positive Benefit-Cost Ratio of 1.09.

Harris County Flood Control District Single-Family Home Acquisitions

Total cost = $16.7 million with federal government paying $14.7 million.

Harris County Flood District seeks to mitigate 61 structures: 23 Severe Repetitive Loss structures, 17 Repetitive Loss structures, and 21 at risk of continual future flooding. HCFCD would acquire and demolish structures, then convert the land to open green space. The project has a positive Benefit-Cost Ratio of 1.09.

Harris County Flood Control District Commercial Acquisition

This is a $3.7 million buyout with the federal government picking up the whole tab.

Harris County Flood Control District wants to buy out a hotel on the east freeway with a severe repetitive loss history. HCFCD would demolish the property and convert the land to open green space. The project has a positive Benefit-Cost Ratio of 1.84. The grant application notes that since 1979, FEMA has paid out $8 million in NFIP claims on this property.

City of Houston Single-Family-Home Elevation Project

Total Cost $1.5 million (all paid by federal government) to elevate 5 severe-repetitive-loss homes ($300,000 each). All would be elevated at least 2 feet above the 500-year floodplain. That would hopefully reduce or eliminate future NFIP claims. The project has a positive Benefit-Cost Ratio of 1.1.

Jersey Village Single-Family-Home Elevation Project

Total Cost $4.9 million with federal government covering $400,000.

Jersey Village seeks elevate 16 structures: 10 are Severe Repetitive Loss, five Repetitive Loss and one at risk of continual future flooding. Elevation will raise structures one-foot above Base Flood Elevation per the City’s freeboard requirements. The project has a positive Benefit-Cost Ratio of 1.32.

Montgomery County Single-Family-Home Acquisition and Demolition

Total Cost = $12.6 million with federal share of $12.4 million.

Montgomery County seeks to mitigate 40 flood prone structures (31 Severe Repetitive Loss and 9 Repetitive Loss structures) by acquisition, demolition, and the conversion of land to open green space. The project has a positive Benefit-Cost Ratio of 1.36.

Tammy Gunnels’ Home in Porter is an example of a Severe Repetitive Loss Home. It flooded like this 13 times in 11 years and was bought out yesterday as part of another Montgomery County grant. Before the buyout, it cost FEMA more than 3 times its fair market value and would have continued flooding had nothing been done.
Pearland Single-Family-Home Elevation Project

Total Cost $500,000, all covered by federal government.

The City of Pearland seeks to mitigate two Severe Repetitive Loss structures by elevation one-foot above the Base Flood Elevation per the City’s freeboard requirements. The project has a positive Benefit-Cost Ratio of 1.08.

Taylor Lake Village Single-Family-Home Elevation Project

Total Cost $2.77 million with federal government covering $2.75 million.

Taylor Lake Village wants to elevate eight Severe Repetitive Loss structures and one Repetitive Loss structure one foot above the 100-year flood level. The project has a positive Benefit-Cost Ratio of 3.1.

In each of the projects above, the owners have all voluntarily committed to the elevation or demolition of the structures.

Recommendation of TWDB Staff

The Executive Administrator of the TWDB recommends that his board approve all these grants. This program meets the agency’s objectives of providing financial assistance to communities to reduce or eliminate the long-term risk of flood damage and to become more flood resilient.

Meeting Details

The Board meeting will be held on Thursday, October 7, at 9:30 a.m. via GoToWebinar  If you wish to address the Board, please fill out the visitor registration form and send it to Cheryl.Arredondo@twdb.texas.gov no later than 8:00 a.m. on October 7. For more information, please visit the TWDB’s website.

Posted By Bob Rehak on October 7, 2021

1495 Days since Hurricane Harvey

Reality Check: Easy Way to Learn About Flood-Mitigation Projects in Your Area

It’s time for a reality check, folks. I meet regularly with Harris County residents from almost every watershed. Virtually all of them have one thing in common. Rich and poor alike see NO Harris County Flood Control District (HCFCD) projects in their watersheds. Yet as of the end of the first quarter, out of 181 total 2018 Bond Projects, 19 were completed, 141 were active, and only 21 had not been initiated.

Gap Between Perception, Reality

So what accounts for the gap between perception and reality?

  • Most projects are practically invisible from streets. They’re “hidden” behind fence lines, tree lines, gates, or often, under forest canopies.
  • They’re scattered over dozens to hundreds of square miles. Often, they happen outside of residents’ normal traffic patterns in unfamiliar neighborhoods.
  • Most people have only a sketchy idea of which watershed they live in.
  • People could drive by projects and not realize they were flood-control construction as opposed to some other kind.
  • The projects are often disguised as parks, wetlands or natural areas when finished.

I lunched last week with three people from Cypress Creek who swore that nothing was happening in their 205-square-mile watershed. But actually, within the watershed, HCFCD has spent:

  • $260 million since 2000, the fourth most of any watershed in Harris County.
  • $169 million since Harvey – more than any other watershed – period – since Harvey.

Simple, Three-Step Reality Check

So where did all the money go? Here’s an easy, three-step way to learn…that applies to any watershed in Harris County:

  1. Go to www.HCFCD.org
  2. If you know your watershed, select it from the list. If not, type your address in the search bar just above the list.
  3. You’ll be taken to a page that lists recent, current and planned projects in your watershed. Click through them and start digging down several levels to learn more about the status of each.

Want to verify the information? Make a list and get in your car. I did that this morning and checked out four Cypress Creek projects between the Katy Prairie and I-45.

It took an hour of planning, three hours of driving, and another 3 hours for drone photography. The hardest part was finding favorable drone launch sites near the projects. But sure enough, all the projects existed. Here’s what I found.

Katy-Hockley Wetlands Mitigation Bank

The Katy-Hockley Wetlands Mitigation Bank. 152 acres that will be part of a 440-acre tract set aside for wetlands mitigation. Note additional wetlands in the upper right and below.
Detail from upper left of first photo. At same site.

The property will remain protected under a conservation easement with the Katy Prairie Conservancy. The wetlands may be used in the future to offset unavoidable wetland impacts caused by other federally permitted projects.

T.C. Jester Stormwater Detention Basin

South of Cypresswood Drive, HCFCD has 171.5 acres of land split by T.C. Jester. Eventually, this whole area could become one large detention pond. The east side of TC Jester is still undergoing a preliminary engineering review, but excavation has already started on the west side.

East of T.C. Jester at Cypress Creek (foreground).
West side of T.C. Jester where excavation has already begun.
Start of excavation on west side of T.C. Jester.

The purpose of these projects: to construct stormwater detention on the main stem of Cypress Creek, which will work to reduce flood risks and damages during heavy rains.

A regional drainage study for the watershed found that flooding along tributaries of Cypress Creek is predominately caused by stormwater from a rising Cypress Creek backing up into tributaries. Stormwater detention basins could reduce that backwater.

The study recommends nearly 25,000 acre-feet of additional stormwater detention in the watershed. This one area could go a long way toward meeting that goal.

Cypress Creek Tributary K-163 Conveyance Improvements

At Timberlake Drive and Cypress North Houston Road, HCFCD is replacing a shallow, silted-in ditch with 8’x6′ reinforced concrete box culverts. Depending on the location along Timberlake, there are either two or three such box culverts side by side.

The project is replacing a portion of an existing earthen channel with 4,750 linear feet of boxed culverts, including inlets, junction boxes and tie-ins with subdivision outfalls.

This ditch was down to a two-year level of service and had flooded neighborhoods on both sides on multiple occasions.

The project will also include the installation of approximately 1,200 linear feet of erosion control for the channel downstream nearer the confluence with Cypress Creek in the distance.

Ridge Top Channel Improvements

Another ditch (K129-00-00) farther east parallels Ridge Top Drive in the Ponderosa Forest area of northwest Harris County.

Here, HCFCD replaced the concrete lining in the entire channel. That included about 3,800 linear feet from Saddlecreek Drive to Cypress Creek. The project also repaired multiple sinkholes or voids that had developed in some areas as a result of stormwater undermining the original channel lining. 

Major Maintenance by HCFCD on K129, a Cypress Creek Tributary
Early stages in the design of this project took place prior to the 2018 Bond Election. Construction began in October 2018 and was completed in January 2020.

More than Cypress Creek Projects in the Works

Altogether, I counted more than 20 projects in Cypress Creek at various stages of development. They included:

  • Swales for extreme rainfall events
  • Right-of-way acquisitions and floodplain preservation
  • Buyouts
  • Neighborhood projects
  • Stormwater detention basins in various stages of planning and construction
  • Channel conveyance restorations
  • Major maintenance projects

Knowing that improvements are happening sure beats living in fear that they aren’t. So do a reality check of the watershed around you.

Posted by Bob Rehak on 7/24/2021

1425 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.

SJRA Board Accepts Grant Funding for Three Studies

Yesterday, the San Jacinto River Authority (SJRA) Board accepted three grants from the Texas Water Development Board (TWDB) to conduct studies for various projects. This was expected. The SJRA had applied for each of the grants about a year ago. The vote, however, now obligates the SJRA. It’s somewhat like applying for a loan and then signing the contract after it is approved.

Three Studies Now Teed Up

The SJRA and its partners can now officially start three studies:

  • An upper San Jacinto Watershed regional sedimentation study
  • A conceptual engineering feasibility study for flood-control dams in the Spring Creek Watershed
  • A joint reservoir operations study between Lake Conroe and Lake Houston
Lake Houston Gates can discharge only 10,000 CFS (left), while Lake Conroe’s can discharge 150,000 CFS. To help provide better watershed management, the Coastal Water Authority is studying the addition of 1000 crest gates to Lake Houston, necessitating the joint reservoir operations study.

Why Flood Mitigation Takes So Long

We are all learning together how long flood mitigation takes. It’s somewhat frustrating to see a conceptual engineering feasibility study being kicked off one month from the fourth anniversary of Hurricane Harvey.

I’m not pointing fingers at the SJRA, its partners, the TWDB, or the State. If you took the time to read all of the approximately 1500 posts on ReduceFlooding.com, you would see that:

  • Harvey happened right after the 2017 legislature finished its work.
  • Eighteen months elapsed before the legislature met again.
  • It took another nine months for the legislature and governor to approve flood mitigation funding.
  • Then, the TWDB needed to define rules for the distribution of funds, solicit public comment, refine the rules, solicit grant applications, and evaluate them in a competitive context.
  • Finally, add time for related preliminary studies such as the Lake Houston Spillway Improvement Project, the San Jacinto River Basin Master Drainage Study, a sand trap study, and a siting study for the flood-control dams.
  • And don’t forget the time to find partners and develop political consensus around solutions.

Still Years from Construction

The truly scary thing is that even when these studies are completed, we still could be years from construction and more years from completion of any of these projects.

For instance, we just started final engineering on the Lake Houston Spillway Improvement Project. Best-case projections show completion of the project in mid 2024 – 7 years after Harvey.

The system seems set up to protect money more than people. We certainly don’t want people rushing off, building half-baked projects that endanger people downstream, the environment, or the safety of a dam…especially if they produce no demonstrable benefit.

But we also don’t want people to flood multiple times waiting for flood-mitigation improvements. And some have. Remember Imelda? Just a thought as we head into the heart of hurricane season.

Studies Could Take 18 Months to 4 Years

The Spring Creek Flood-control Dam study will take 18 months. The Joint Reservoir Operations Study will take 3 years. And the Sediment Study is scheduled to take 4 years, though Matt Barrett, SJRA’s flood-mitigation director, is trying to compress that to 18 months.

If you missed the original post about these three studies, you can find more details here. SJRA partners in these projects include Harris County Flood Control, City of Houston, City of Humble, Montgomery County and five utility districts.

Posted by Bob Rehak on July 23, 2021

1424 Days since Hurricane Harvey and 673 since Imelda

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

Flood-Mitigation Funding Flows to Damage, Not High-Income Neighborhoods

Last in an eight part series on flood-mitigation funding in Harris County

For two years, Precinct 1 Commissioner Rodney Ellis and Precinct 2 Commissioner Adrian Garcia have alleged that rich watersheds get all the flood-mitigation funding, while poor and minority watersheds get none. But data suggests that is far from the truth.

Three months ago, the din from Ellis and Garcia reached a crescendo. I became so alarmed about the allegations of racism in flood-mitigation funding, that I submitted a Freedom of Information Act (FOIA) Request to Harris County Flood Control District (HCFCD) for historical funding data by watershed. I also requested related data such as watershed size, damaged structures, the number of low-to-moderate-income (LMI) residents, and more.

Data Contradicts Ellis/Garcia Narrative

My analysis contradicted the carefully crafted Ellis/Garcia narrative. I found the exact opposite of what they claimed.

The most dollars flow to low-income watersheds which, coincidentally, have the most flood damage.

The strongest correlation I found with flood-mitigation “funding” since 2000 was “damaged structures.” And the percentage of low-to-moderate income residents in a neighborhood correlates very strongly to damage per square mile.

When you think about this, it makes sense. We put the most flood-control dollars in areas that flood the most.

Damage Per-Square Mile Correlates Highly with LMI %

To understand patterns in the data, one must start by evaluating damage “per square mile.” That’s because high- and low-income watersheds differ radically in size and number.

  • Harris County has only eight low-to-moderate income watersheds, but 15-high income watersheds.
  • The low-income watersheds are half the total size – 600 square miles vs. 1176 square miles.

When looking at damage on a per square mile basis, the highest concentrations occur in low-income neighborhoods.

LMI percentage and damaged structures per square mile have a 0.82 coefficient of correlation. Mathematicians consider that very strong. 1.0 is the highest you can get, a perfect correlation.

Damage includes structures flooded in four major storms since 2000 (Allison, Tax Day, Memorial Day and Harvey).

Low-income watersheds cluster on the left and high-income watersheds on the right because of “Damage,” not racial discrimination in mitigation funding. Mitigation dollars already overwhelming flow to minority and low-income neighborhoods as they have for decades.

Flood-Control Dollars Flow to Damage

There’s also a strong relationship between total funding and total damage. Notice how the shape of the curves align closely with a few exceptions.

Total funding since 2000 and the number of damaged structures show a 0.84 coefficient of correlation. Mathematicians consider that very strong.

You can see a general downward trend in both blue and orange, indicating a strong correlation. This relationship supports other statistical analyses in this series. (See links to previous articles listed below.)

At the highest level, when you look at the data from multiple perspectives, one thing stands out: 

Dollars flow to damage, not affluent watersheds.

Possible Causal Links Between LMI Percentage, Damage and Funding

Touring lower income watersheds by car or helicopter helps explain why those watersheds have so much more damage and consequently receive so much more funding. In general, they:

  • Are much more densely packed with buildings, a consequence of more than twice the population density (3,900 residents/square mile compared to 1,600).
  • Have more impervious cover, so water can’t soak in as quickly or as much
  • Tend to crowd floodways and floodplains, which have expanded over time with upstream development
  • Are downstream from rapidly growing areas.
  • Are 70 to 80 years old and therefore built to lower development standards
  • Have many homes that sit almost at street level instead of being elevated above it.
  • Have many clogged roadside ditches and storm drains, due to poor maintenance by county precinct crews and the City of Houston’s Public Works Department. (Water has a hard time getting out of neighborhoods.)
  • Have more structures per acre.

Re: the last point, in Kashmere Gardens (an LMI neighborhood), I found six homes on a third of an acre worth more than my house on a full acre in Kingwood. The density can offset higher home values in suburban neighborhoods when calculating Benefit/Cost Ratios for FEMA or HUD.

Flood-Mitigation Funding by Watershed Since 2000

Here’s how much money each watershed received for capital improvement projects since 2000. No maintenance dollars or dollars committed to complete projects are included – only dollars “out the door” as of the end of March 2021.

The graph above dramatizes two things: 

  • The wide variation from high to low. Luce Bayou received only $4.5 million while Brays received $510 million. That’s 113 to 1.
  • few watersheds received multiples of the average and median, while far more received a small fraction.

Funding Data Disproves Racist Allegations

Remember that the next time you hear the allegations of racial discrimination from Ellis and Garcia. This discussion shouldn’t be about race. It should be about fixing flooding problems.

The government is not funding flood-control projects in rich areas that didn’t experience flood damage. It funds them in areas that had the MOST damage. Those just happen to be in minority and low-income neighborhoods. And it is critical that people focus on WHY those structures flooded if we are to find solutions. 

Implying that they flooded because of racial bias is misdirection. The racial allegations divide and distract people. They also keep HCFCD, from focusing on real solutions to our flooding problems. That harms all voters in Harris County.

If commissioners continue to focus on race, it will prove they care more about political gamesmanship than fixing drainage.

While that may win them re-election, we all lose.

For More Information

For more information, see: 

Posted by Bob Rehak on 6/28/2021

1399 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.