When Harris County Flood Control District (HCFCD) and the Army Corps began Project Hunting (the Hunting Bayou Federal Flood Risk Management Project) in 2014, they estimated it would cost $100 million and take until late this year.
A flyover of the construction along Hunting Bayou looks like it is nearing completion…right on schedule. It will soon be done, except for the backslapping. Compare the shots below to those I took last year.
Hunting Bayou runs just inside North Loop 610 most of the way from US59 to Wayside. However, starting at Wayside, it dips outside the Loop, then goes back inside again, and finally outside a second time. Eventually, the Bayou works its way to the Houston Ship Channel near the City of Galena Park.
Scope of Project
Project elements include:
Excavating a stormwater detention basin on a 75-acre site near the northeast corner of Homestead Road and Loop 610
Widening and deepening about 4 miles of Hunting Bayou
9 bridge replacements / 8 modifications and channel conveyance improvements under bridges
Project Benefits
HCFCD says that most neighborhoods near the bayou will see water surface elevation reductions of 3-4 feet for the 1 percent annual chance (100-year) flooding event. The number of homes and businesses subject to the 1 percent (100-year) flooding event would drop from 5,100 to 650. And all homes and businesses will benefit from the reduced frequency and depth of flooding.
Need for Project
The Hunting Bayou watershed has Harris County’s second highest percentage of Low-to-Moderate Income (LMI) residents – 69%. That means more than two out of every three people earn less than the average income for the region.
Hunting is a small watershed. It comprises only 31 square miles. Its size ranks 19th out of 23 watersheds in the county.
Population grew only by 2,323 residents between 2010 and 2020. It went from 75,908 to 78,231. That now ranks it 14th in population among all watersheds, and 8th highest in people per square mile.
In five major storms between 2000 and today (Allison, Tax Day, Memorial Day, Harvey and Imelda), floods damaged 15,763 structures in the watershed. But virtually all of that damage came from Allison (8,270) and Harvey (7,419). The other three storms combined damaged only 74 structures, according to statistics compiled from HCFCD Federal Reports.
Thus, Hunting ranked 7th in total damage out of 23 watersheds, but because of its small size and high density, it had 508.5 structures per square mile damaged by floods since 2000. That means…
Hunting ranked #2 out of 23 watersheds in damage per square mile.
Data Obtained from HCFCD Via foia request
The watershed is highly urbanized with a mixture of residential, commercial and industrial developments. It’s home to one of the largest rail yards in the Houston area.
Union Pacific Englewood Yard in NE Houston along Liberty Road (right). HCFCD had to replace three railroad bridges over Hunting Bayou as part of the project.
Aerial Survey Shows Mitigation Construction Almost Complete
On Tuesday this week, I flew over Hunting Bayou with Ken Williams and Bill Callegari. Both are fellow members of the Harris County Community Flood Resilience Task Force. The pictures below show highlights of the construction.
Looking west at Hunting Bayou while hovering over US59 North. The widening of Hunting stretches downstream for about 4 miles to where Loop 610 North (on the left) turns right and heads south.Same area. Looking SW toward 59 and downtown. Notice the rip rap (irregular chunks of broken concrete or rock) below storm sewer outlets. It disperses the force of rushing water and slows it down to reduce erosion.Work continues around two neighborhood bridges at Falls St. and Leffingwell St.Likewise, widening continues at Hirsch Road.Looking back upstream at all three bridges, plus a pedestrian bridge over a small tributary in the distance.Wider shot, looking upstream over Wayne Street.Previously finished section around Wipprecht bridge.Note how bayou narrows under Lockwood Bridge due to commercial development on either side.Looking back upstream (west) from over Kelly St. at linear park that parallels another large detention basin.Note the new pedestrian bridges.They have been widened to accommodate the wider bayou.Rotating 180 degrees from shot above, we can see downstream to rest of park and where the Bayou threads its way under Loop 610N. Also note large detention basin in distance.Looking back SW from over Kelley Street. Note concrete lining that now protects narrow section under 610 bridge.Looking SW toward Homestead Road (with the bridge) across the new 75 acre stormwater detention basin.
The Curtis M. Graves Detention Basin shown above provides approximately 1,000 acre-feet of stormwater storage capacity. That’s almost 10 inches of rain falling over a square mile. Construction of the basin began in 2020.
Looking west along 610 N at the section of Hunting that briefly dips outside of the Loop.Looking NW. Note again the new concrete lining where the channel narrows to go under the Loop 610 N bridge. Water flows toward the camera.
Compare Bayou Downstream From Project
Where the bayou narrows to go under a bridge, the increased water pressure during a flood can cause a “jetting” phenomenon that rapidly erodes banks and undermines bridge supports. Hence, the need for concrete reinforcement.
Looking S along East Loop 610 beyond the eastern end of the project. The Bayou loops around storage tanks (lower right) and heads south toward Wallisville Road, before heading east again. This shows what the bayou looked like before widening.Compare width to previous shots.
The tank farm is the approximate eastern limit of Project Hunting.
Project History
This project began on December 16, 2014, long before Harris County’s Flood Bond in 2018. It was a key project of County Commissioner El Franco Lee (who lived in the area) and Congressman Gene Green. Despite a low benefit/cost ratio, they called in favors and got the project started.
The agreement between the Army Corps and HCFCD lets HCFCD qualify for reimbursement from the Federal government for work completed.
Between the channel widening and detention basin, HCFCD has removed almost a million cubic yards of soil to create more room for floodwaters. Width of the Bayou now varies from about 30 to more than 500 feet between the project limits.
According to data obtained via a FOIA Request, HCFCD and its partners spent $96 million on Hunting Bayou between 2000 and the end of last year. Some of that money has been spent on other projects. To see a complete list of HCFCD projects in Hunting Bayou, visit the District’s Hunting page.
Since 2000, Harris County Flood Control District (HCFCD) and its partners have spent more than a half billion dollars to reduce flooding in the White Oak Bayou watershed. And they aren’t done yet. Before the flood bond is complete, they will have spent at least $575 million to create detention basins, widen channels and make other improvements.
On 7/19/2022, I flew up White Oak Bayou in a helicopter with Bill Calligari and Ken Williams, two fellow members from the Harris County Community Flood Resilience Task Force. Our goal: to learn what the money bought.
This is the second of four posts. The first covered Greens Bayou. The next two will cover Hunting and Halls Bayous.
White Oak Bayou by the Numbers
White Oak Bayou is Harris County’s sixth largest watershed but its third most populous. 51% of its residents qualify as Low-to-Moderate Income (LMI). It’s our fourth most densely populated watershed (people/square mile). Not surprisingly it had the third most damage in 5 major storms since 2000 (Allison, Tax Day, Memorial Day, Harvey, Imelda). The storms damaged 25,739 structures. Look at some of the photos below of structures crowding the bayou and you will understand why.
White Oak Bayou from the Air
White Oak Bayou flows southeast from its headwaters northwest of FM 1960 to its confluence with Buffalo Bayou near downtown Houston. The watershed comprises 111 square miles, with 146 miles of open streams. They include:
White Oak Bayou
Little White Oak Bayou
Brickhouse Gully
Cole Creek
Vogel Creek
Our helicopter started the White Oak leg of our flight near the Heights north of downtown. From there, we flew upstream. This is what the Heights looks like from the air – a study in population density which correlates highly with flood damage.
White Oak drains most of the Heights. Note the density of development. In 2010, the watershed census was 433,250. But by 2020, it had increased to 464,933.
Looking south toward downtown from over Ella and TC Jester. Most of this segment of the bayou was finished years ago and requires only repairs now.Looking W, upstream from over West 34th and TC Jester.
HCFCD now maintains White Oak and has observed a number of locations where concrete is approaching the end of its useful life.
Looking upstream from over Garapan Street just north of Tidwell at bank and concrete repairs.(Arbor Oaks buyout area is in upper right. See end of post.)
Some projects are still being studied. Some are complete or nearly so. As of June 8, 2022, HCFCD was working out a contractor issue on the largest project, which will delay the originally scheduled completion this summer.
Federal Flood Damage Reduction Project
The largest project is the White Oak Bayou Federal Flood Damage Reduction Project. This $124 million project will substantially reduce flooding risks along White Oak Bayou. It started in 1998 in partnership with the U.S. Army Corps of Engineers, with the Flood Control District designated as the lead. The two segments of the project are fully funded to completion.
Upstream segment of Federal Project.
Limits of downstream segment of Federal Project
They include:
Construction of approximately 15.4 miles of channel conveyance improvements along the bayou from FM 1960 to Cole Creek near West Tidwell in the two segments above.
Excavation of six stormwater detention basins to hold almost one billion gallons of stormwater. That’s enough to hold a foot of rain falling across almost 5 square miles.
Construction of the Jersey Village Bypass Channel
Stretch of improvements upstream from Alabonson Road.
Upon completion, HCFCD estimates that most parts of the project area will see water surface elevation reductions of 0.1 to 1.8 feet for a 1 percent annual chance (100-year) flooding event.
HCFCD
Looking S.White Oak Bayou Detention Basin near West Little York and Hollister.Looking S toward White Oak Bayou near Fairbanks North Houston Rd. Basin completed in 2021A smaller detention basin opposite the one above skirts the south side of White Oak at Fairbanks North Houston (bottom right).Channel improvements and greenbelt trail still under construction.Looking west at White Oak where it crosses under Beltway 8. Note bridge improvements and vegetated detention ponds on left on both sides of bayou.
Many smaller detention ponds like those above now line both sides of the bayou and its tributaries from upstream to down.
Arbor Oaks Subdivision Buyout
Since 2003, HCFCD has bought out more than 200 homes in the Arbor Oaks subdivision. It is still buying more on either side of Vogel Creek to build a 431 acre-foot stormwater detention basin and restore the floodplain. That would hold a foot of rain falling over 2/3rds of a square mile.
Acquisition costs in such densely populated neighborhoods can easily exceed construction costs.
This part of the White Oak story dramatizes how costly, difficult and time-consuming it can be to buy out and mitigate areas built in floodplains.
Note the large areas with streets marked, but few or no homes on them. They were bought out and this area will become another large detention basin. Image courtesy of Apple Maps.
Here’s what part of it looks like from a few hundred feet up.
Lower part of Arbor Oaks area on bottom left.Bridge is on West Little York. Looking SE toward downtown.Looking SE at floodplain south of Little York near Arbor Oaks. Note aging concrete along White Oak Bayou on right.
And then there’s the North Canal near downtown. HCFCD and the City of Houston are working to finalize an interlocal agreement. Grant funding calls for completion of the first phase of the project by May 2023.
They all add up to more than a half billion dollars…and counting! Water needs somewhere to go during a storm. If we don’t leave a floodplain for floodwaters to safely expand, they will wind up in peoples’ living rooms.
Posted by Bob Rehak on 7/20/2022
1786 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/07/20220719-RJR_9908.jpg?fit=1200%2C800&ssl=18001200adminadmin2022-07-20 20:54:042022-08-29 14:45:27White Oak Bayou: What A Half Billion Dollars Looks Like
Harris County Flood Control District (HCFCD) and its partners continue to add detention basin capacity along Greens Bayou to reduce the risk of flooding. I flew in a helicopter today with fellow Harris County Community Flood Resilience Task Force members Ken Willians and Bill Calligari. We flew over Greens, Halls, Hunting, and White Oak Bayous. In this post, let’s focus on what we found in Greens.
From west to east, we flew over the Cutten Basin at 249 and Beltway 8, then followed the bayou over the Antoine, Kuykendahl, Glen Forest, Aldine-Westfield, and Lauder Basins. Some have recently completed construction. Others are still under construction. Here’s a rundown of everything between US249 and US59 along Greens.
Cutten Basin
Scheduled for completion later this year, the Cutten Basin covers approximately 250 acres. It includes five compartments, four south of Greens Bayou and one north. When complete, it will hold 850 acre feet of stormwater. That’s enough to hold a foot of rain falling across approximately 1.3 square miles. It will lower the water surface elevation along Greens by a third of a foot in a hundred-year flood.
Looking S toward Beltway 8. Greens Bayou flows from right to left through the center of the frame. Looking East. Greens cuts through the upper left portion of the frame. Beltway 8 cuts through the upper right.Looking West across Hollister which cuts through the middle of the frame.
Antoine Basin
HCFCD and the Army Corps started the $80 million Antoine Basin in 2015. The Army Corps designed and built it. Satellite photos in Google Earth first show it holding water in November 2020.
Looking east along Greens toward the Antoine Basin, top right.Looking SW. West Greens Road arcs through center of frame. Greens flows from upper right to lower left. Beltway 8 near top of frame.
The completed basin holds approximately 1,650 acre-feet, or 538 million gallons of stormwater. To put that in perspective, it holds a foot of rain falling over a 2.5 square mile area, or half a foot falling across 5 square miles!
Kuykendahl Basin
Kuykendahl Stormwater Detention Basin sits on a 288-acre property near Kuykendahl Road and Ella Boulevard along an unnamed tributary of Greens Bayou. In floods, it holds water back from entering the bayou and then releases it safely and slowly after the storm has passed.
Wide shot of Kuykendahl Basin looking westKuykendahl in foreground. Note how densely populated the area is with apartments.
Contractors removed 3.61 million cubic yards of soil from the site. It holds 2,325 acre-feet, or 757.6 million gallons of stormwater. That’s a foot of rain falling across 3.6 square miles, or half a foot falling across 7.2.
Following construction, contractors planted 22.19 acres of native tree and shrubs, and 12.79 acres of stormwater quality-treatment wetlands. They also created 14.04 acres of other wetlands to replace those impacted by construction.
Ceres Environmental Services Inc. constructed the Kuykendahl basin and another to the east (see Glen Forest below). Combined, they were the largest construction contract ever managed by HCFCD up to that time. The two basins reduced or removed flooding risks and damages from more than 1,100 structures along Greens Bayou. “Avoided damages” exceed $90 million in every flood. Far more than the cost of construction.
FEMA awarded $39.2 million to the Harris County Flood Control District, under the Hurricane Ike Hazard Mitigation Grant Program (HMGP) to construct the basins and HCFCD contributed matching funds.
Google Earth satellite photos indicate construction finished for both basins in 2020.
Glen Forest
Farther east along Greens, the Glen Forest Detention Basin extends from I-45 to Imperial Valley north of Greens Road.
Looking East across I-45 at Glen Forest Basin.Looking West at Glen Forest Basin on Greens Bayou between I-45 at top of frame and Imperial Valley Drive under camera position.
The Glen Forest Basin project removed approximately 2.15 million cubic yards of soil in three connected cells. The completed basin holds approximately 894 acre-feet. That’s 1.4 square miles one foot deep or 2.8 square miles a half foot deep.
Aldine Westfield Basins: Phases 1 and 2
Farther east along Greens Bayou, directly south of Houston’s Bush Intercontinental Airport, you will find two more new basins. HCFCD completed construction on the first in April 2021. The second (to the north) then began construction and has not yet finished.
Looking East from over Aldine Westfield Road in foreground at Phase One. Beltway 8 in upper right. Note Greens Bayou turning south under Beltway in upper right.Looking ENE. Phase 2 is still under construction on Aldine-Westfield Road immediately north of Phase 1 (lower right). Note airport tower on horizon.
The two basins when complete in 2024 will hold a foot of rain falling over more than 2 square miles (1260 acre feet). That concludes your helicopter flight down Greens Bayou for today.
Greens by the Numbers
Together, these basins should hold approximately a foot of rain falling over 12 square miles.
That’s not enough to prevent flooding in another Harvey. But it will certainly reduce flooding for thousands of people. HCFCD has not yet released updated flood-risk data for the mid- and upper reaches of Greens Bayou (shown above). More news on that when it becomes available.
According to data obtained from HCFCD via a FOIA Request, Flood Control and its partners have spent more than $435 million on flood mitigation in Greens Bayou between 1/1/2000 and the end of last year. That includes money spent on all phases of all projects shown above.
Only three other watersheds have received more funding since 2000: Brays, White Oak and Sims. But more on those later.
Greens was the second most heavily damaged watershed in five major storms (Allison, Tax Day, Memorial Day, Harvey, Imelda). Those storms damaged more than 29,000 Greens structures.
58% of the population of Greens has low-to-moderate income (LMI). That ranks 6th on the LMI scale of Harris County watersheds.
This morning at 10:34 AM, the last remains of another Forest Cove townhome complex toppled to the ground. The HCFCD demolition contractor nibbled away at it last week and earlier this morning. Eventually, all but a narrow strip of the last townhome in the complex had turned into a pile of rubble.
That strip started to lean. Then, suddenly, one more touch from the excavator, and the building collapsed on itself with a billowing cloud of dust and a thunderous boom. When the dust cleared, only one last complex remained standing.
As of Saturday, 7/16/22, one of the last three buildings was completely gone along with half of the second.Early Monday, 7/18/22, demolition of the remaining portion of the second building started again.As the excavator clawed away at the building, it started to lean.Periodically, the excavator would pile more rubble under itself so it could then reach higher. Note falling doors, walls and floors, frozen in space by the camera’s fast shutter speed.What took months to build came down in seconds.Note the severe bowing of the wallon the right.
Final Collapse Caught on Camera
At this point, I sensed the building would soon collapse. So, I switched from the drone to my Nikon which can shoot many more frames per second. And then it started…
With parts of the second and third floors removed, along with most of the truss structure in the attic, the remainder of the building started to collapse in on itself.A chimney came tumbling forward.The final collapse took less than 10 seconds. Three minutes later, the dust had cleared.
Next Steps
Contractors will extract any recyclable waste from the rubble. Then, they will crush what remains so that it takes less space in a landfill. Finally, they will remove the concrete from the foundation and likely recycle that, too.
Eventually, this area will return to nature. However, what form that takes has not yet been determined. Typically, HCFCD partners with other organizations such as the Houston Parks Board to create and maintain improvements such as trails, parks or recreational space. In fact, the Houston Parks Board West Fork Trail currently ends behind the rubble in the photo above. The Parks Board plans to extend it to Edgewater Park at US59, so hikers and bikers can connect from the Kingwood Trail System to the Spring Creek Greenway.
Demo Date for Last Building
After this morning, only one Forest Cove townhome complex remains standing. That’s at 1020 Marina Drive near the community swimming pool. According to Amy Stone, a Flood Control District spokesperson, HCFCD will demolish that building starting August 1, 2022. More news to follow.
Posted by Bob Rehak on 7/18/2022
1784 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/07/20220718-DJI_0249.jpg?fit=1200%2C799&ssl=17991200adminadmin2022-07-18 13:22:152022-07-18 14:54:27Caught on Camera: Moment Forest Cove Townhome Toppled
The San Jacinto River Authority (SJRA) has completed its initial sand trap study, in partnership with Harris County Flood Control, and reviewed public comments. According to Matt Barrett PE, SJRA’s Manager of Water Resources and Flood Management, the SJRA is working toward a pilot study. But a successful pilot will require several things including funding partners and consultation with regulatory agencies, such as TCEQ and Texas Parks and Wildlife.
The goal of the project: intercept and remove sediment migrating downstream to reduce buildups elsewhere.
West Fork mouth bar after Harvey and before dredging. A small area at the far right had been building up before Harvey. The rest appeared when Harvey’s floodwater’s receded.
The proposed pilot sand trap could not possibly remove enough sand by itself to prevent the build up of another giant sand bar like the one above. However, a network of such traps might help.
Consultation with Regulatory Agencies
In Texas, among other things, TCEQ regulates floodplains, sand mining, and water quality. Texas Parks and Wildlife regulates rivers between the vegetation on each bank.
Possible location of trap for pilot study outside Hallett Mine on West Fork. Trap would consist of a trench through the middle of the point bar in the foreground.
But a trench at this location might run afoul of new TCEQ BMPs for sand mining that specify 100-foot buffer zones adjacent to perennial streams greater than 20-feet wide.
Schematic diagram of proposed trap at location above from initial conceptual design study finished before TCEQ adopted new BMPs.
Finding Funding Partners
SJRA must also find funding partners as it does not have a revenue source to pay for a pilot study and full construction costs of sand traps. In that regard, Barrett mentioned Harris County Flood Control and City of Houston as potential partners.
Barrett is also exploring partnerships with APOs (Aggregate Production Operations, aka sand mines). Sand mines can help defray expenses by removing sand from the traps as it accumulates. Of course, their desire to do that will depend on the location of the traps. They would prefer something close to their mines to minimize transportation costs and logistics while maximizing salability of the sand.
Hungry-Water Concern
Barrett also mentioned the need for the preliminary engineering design to avoid a “hungry water” effect which might increase erosion downstream. Hungry water results when streams have more power to transport sediment than they have available sediment. As a result, it erodes stream beds and banks to compensate.
Would Program be Extendable if Successful?
In a wide-ranging 45-minute discussion with Barrett, I raised several other potential issues. They included:
Location of the test near APOs, far upstream from the heavily damaged areas near Lake Houston where sand accumulates. There are no active sand mines between Humble and Kingwood – and few on other tributaries.
No sediment gages upstream and downstream from the test site. Not having a way to demonstrate success could limit future expansion of the program.
Potential partners that could remove sand from traps NOT located near APOs. You need a way to get sand out of a trap after it fills up. If the City of Houston or HCFCD established an ongoing maintenance dredging program, that could solve this issue.
How long an APO will remain committed to a location near a trap. After going to the expense of building a trap, SJRA would want to make sure the APO didn’t move operations to another location in a year or two. For example, some sand miners have talked about moving to the East Fork to take advantage of expected growth associated with the new Grand Parkway extension.
The SJRA must work through such issues to protect the public’s investment in the program. It has many moving parts. And the interests of all partners must align before moving forward.
Outline of Next Steps
So the next steps are:
Find partners with money whose interests align.
Obtain commitments from them.
Consult with regulatory agencies to avoid potential conflicts.
Lock down a location near an APO.
Begin preliminary engineering.
Ensure the pilot study (based on proximity to APOs) can extend to other areas (Rehak concern)
Find a way to measure success to help extend the pilot program if successful
In business, there’s an old maxim: “That which can be measured will be repeated.” Doing a pilot study that can’t be measured or replicated elsewhere helps no one.
The Army Corps has also published extensive research about the effectiveness of different sand-trap designs. Search for “Army Corps sand trap studies.” I originally became interested in the concept when I read a Corps study about a test of different trap geometries in the Mississippi River. There are many alternatives including some that could be located where water slows down at the entrance to Lake Houston (where the Harvey mouth bar appeared in 2017). Such a location would have the advantage of intercepting sediment from all upstream sources, not just the West Fork...if all the tumblers aligned.
Posted by Bob Rehak
1783 Days since Hurricane Harvey
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Mavera, a 1700-acre new development in southern Montgomery County at FM1314 and US242 has finished clearing a large section of land northwest of the intersection and started pouring concrete. Signs welcome visitors to model homes. The area, once laced with wetlands now has a massive linear detention pond and uses FM1314 for outflow control.
Looking east just north of US242 on right from over FM1314. Note wet areas in foreground. They correspond to wetlands in map below.Large green area immediately east of 1314 (diagonal) and north of US242 (bottom) correspond to wet areas in photo above. From US Fish and Wildlife Service National Wetlands Inventory Map
Areas west of FM1314 to Crystal Creek are also being cleared, but their current state of development is not quite as advanced.
Likewise, an area east of FM1314 has expanded north, almost to Gulf Coast Road. Neither is its drainage fully developed.
Looking NE at current limit of development. Gulf Coast Road runs diagonally from left to right just beyond tree line.
Long, Linear Detention
The development relies on a wide linear detention basin – more than a mile long! And that’s only the part east of FM1314!
Looking east toward upstream end of detention basin.
Two smaller basins also exist. One is currently by a small park and recreation center.
Looking WSW.Note small retention pond and rec center in upper right.
In the photo above, also note the small swales that outline lots. Will some drainage go overland? Or is underground drainage just not connected to the detention basin yet?
Same spot. Lower elevation. Looking west from eastern portion of Mavera. I’m not seeing any drainpipes from storm sewers entering pond yet.Note three new model homes near center of frame.
The development seems to have undergone a series of name changes. The land was originally known as the Denbury Tract. Later, construction plans and a drainage analysis refer to it as Madera. But now, the builders are marketing it as Mavera.
Screen capture of cover sheet from drainage planshowing first two names of development.
The drainage plans for Mavera (aka Madera/Denbury tract) rely on a hydrologic timing assessment (see last line in screen capture above).
The drainage analysis claims the development will have no downstream impact, but engineers didn’t study those areas. Nor did they study how new development upstream may have already shifted the peak of a flood.
Impact on FM1314?
Long linear detention schemes typically accelerate the flow of water. This one will rely on one culvert under FM1314 to hold back more than a mile of water collected from hundreds of acres. That will put a lot of pressure on FM1314 in a heavy storm.
Looking NW over FM1314. East is to the right. Water will flow west toward Crystal Creek out of frame to the left.
The roadway will act as a dam to detain water collected from almost all of the area shown in the photo below.
Looking east. Virtually all of the cleared area will drain through one culvert under FM1314. FM1314 runs left to right through the bottom of the frame. US242 is on right. Notice how channel is being widened, making culvert off-center. Did someone initially miscalculate or did plans change?
FEMA mapped most of this area in a ten-year flood zone. For the sake of potential home buyers, let’s also hope the engineers got the drainage calculations right.
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/07/20220716-DJI_0152.jpg?fit=1200%2C799&ssl=17991200adminadmin2022-07-16 15:56:422025-08-19 22:11:03Mavera Wetlands Bite the Dust
The Texas Water Development Board (TWDB) recently produced a fascinating short video that puts the current drought in historical perspective by comparing rainfall, temperature, and water supplies to 2011. The text and visuals below are adapted from Dr. Mark Wentzel’s presentation. Wentzel serves as a hydrologist for the TWDB.
Wentzel’s charts depict statewide averages. The Houston region has had significantly more rainfall. So look at Wentzel’s data for trends happening around us. I’ll show Houston data at the end of this post.
Comparison to 2011 Drought
Wentzel says that June was warmer and drier than normal for much of the state, the fourth consecutive month with those conditions. At the end of June, drought conditions covered 86 percent of the state, up eight percentage points from the end of May. Storage in our water supply reservoirs is at 75 percent of capacity, ten percentage points below normal for this time of year. So, Texas is in a significant drought, the worst since 2011, but not worse than 2011.
Highlights of Wentzel video
Statewide Precipitation Averages
The State average rainfall from January to June of this year: 7.8 inches, about 60 percent of normal. Bad as that may be, it’s better than in 2011 when we received less than six inches in the first half of the year, only about 40 percent of normal.
Statewide Texas precipitation averages
Comparison to 2011 Temperatures
On the next chart, Wentzel shows monthly average temperatures across the entire state for both 2022 in orange and 2011 in red. Black dots show the 20th century average for comparison. He shows maximum and minimum temperature records in gray. The gold line represents January to June of this year.
Statewide Texas temperature averages
Temperatures have been above average five out of six months. That additional heat has certainly contributed to drought, but monthly temperatures in the first half of 2011 were even hotter for four of those six months.
In 2011, the real heat came in June, July, and August when we set maximum temperature records each month.
Dr. Mark Wentzel, TWDB
Temperatures the rest of the summer and 2022 are expected to be warmer than average, but not to exceed 2011 temperatures.
Percent of State in Drought
Low rainfall and high temperatures during the first half of 2022 have brought significant drought to Texas. The U.S. Drought Monitor map for conditions as of June 28 shows 86 percent of the state impacted by drought, up eight percentage points from the end of May. More of the state is experiencing drought at the end of June this year than for any June since 2011, when 96 percent of the state was in drought.
Effect on Water Supply
Statewide, our water supply reservoirs are being impacted by the current drought, but not as significantly as in 2011. The dark line on this chart shows how storage this year compares to minimum, maximum, and median values for the day of the year from data going back to 1990. Lighter lines show how we did in 2021 and 2020. The red line shows how we did in 2011.
Texas statewide totals expressed as percent of full capacity
We began 2022 with water supply storage more than two percentage points lower than normal for the time of year. By the end of June, we’ve fallen to about ten percentage points lower than normal.
In 2011, water supply began the year closer to normal, but fell farther and faster than in 2022. By the end of June, storage was about one and a half percentage points less than this year. In the second half of 2022, Wentzel expects additional storage declines, but not as severe as in 2011 when the State reached 30-year lows by mid-October.
Bottom Line for State
We are in a significant drought, even if it’s not as bad as 2011. But the real test won’t come this summer or even this year. Our water supply systems are designed to withstand a multi-year event. Will 2022 lead to a multi-year event? It’s too early to tell, says Wentzel. “But it’s never too early to conserve water and manage demand.”
The top half of the first shows temperatures. It depicts highs in red, average ranges in green, and lows in light blue for ever day of the year. The dark blue lines show actual temperature observations year to date.
The bottom half shows actual precipitation compared to the average. You can see that for part of the year, we were actually above normal. But starting around June 1, we fell behind.
The last chart shows temperatures in July to date. The dark blue lines show actual temps compared to highs, the normal range, and lows for every date. The three stars indicate records or ties.
Posted by Bob Rehak on 7/15/22 based on information from TWDB, NWS and Dr. Mark Wentzel
1781 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/07/20220715-Screen-Shot-2022-07-15-at-5.03.06-PM.jpg?fit=1200%2C670&ssl=16701200adminadmin2022-07-15 18:09:582022-07-15 18:16:32How Current Drought Compares to 2011
In the last few weeks, Michael Bloom, a fellow member of the Harris County Community Flood Resilience Task Force, and I have debated the inherent bias and limitations of a Flood-Mitigation Benefit Index (FMBI) proposed by a majority of the Task Force to Harris County Commissioners Court.
According to Mr. Bloom, the index will:
Reveal and document patterns of historical discrimination.
Help plan where additional flood-risk reduction investments should be made.
Population-Based, Not Damage-Based Mitigation
The formula is:
Benefit = Total Cost/(Population X Risk)
…where:
Cost = total flood-mitigation construction spending (and only construction spending) that benefits a census tract.
Population = the number of people who live in census tracts.
Risk = the annual chance of flooding (applied to census tract(s)) expressed as a whole number. For instance, a 1% annual chance equals 1. And a 10% annual chance equals 10, etc.
The Task Force hopes to calculate and compare the results for each census tract in the county.
The formula measures the historical per capita flood-mitigation costs supposedly associated with the “current” level of risk in a census tract – NOT historical flood damage.
According to proponents, “a high benefit score means no more mitigation spending is needed. And a low score means more spending is needed.”
But consider these two examples:
4,000 people live with a 1% annual chance of flooding and have received $200 in prior investment. Their FMBI would be 0.05. That’s extremely low. And scores that low indicate such areas need help “regardless of prior investment.”
8000 people live in the 10-year flood plain and have received $10 million in prior investment. Their FMBI equals 125. That’s 2,500 times higher.
According to a spokesperson for the FMBI, “A high FMBI means we don’t need to make more investments in that location.” Yet twice as many people live with ten times the risk in the area with the higher index.
So, who deserves the most help? Residents with the lowest FMBI? The formulaSAYS they need help the most. But they actually have the lowest risk.
The Value of Market Testing
None of the hypothetical examples used to “sell” the formula hint at the possibility of such an upside-down result.
The example above proves several things:
The formula can produce inconsistent and misleading results.
Adjusting for population doesn’t prove historical discrimination. The most densely populated area has 50,000 times more investment.
The formula needs rigorous testing and ground-truthing before going any further. This is a best practice for any new scientific formula – especially one intended to guide future investment.
In addition to producing unintended results, the formula has several other problems that require discussion.
No Right-Of-Way Acquisition Costs Included
The FMBI formula includes only construction costs. It excludes right-of-way acquisition costs by assuming that they are “uniform throughout the county.” Therefore, “…costs included or excluded will not adversely impact results.”
In fact, Right-of-Way (ROW) Acquisition costs are huge and NOT UNIFORM throughout the county. I have documented that ROW costs typically comprise the second most expensive part of flood-control projects.
All Flood Control and partner spending on all capital improvement projects from 1/1/2000 through the end of Q3 2021.Data obtained via FOIA Request from HCFCD.
A quick glance at the Appraisal District website will tell you that land costs vary widely throughout Harris County and change over time.
The cost of buying floodplain land or wetlands for preservation in rural parts of Harris County pales in comparison to land acquisition costs in densely populated parts of the county.
In fact, acquiring land in densely populated areas for flood mitigation often costs more than construction, according to several engineers I consulted.
Compounding Problems?
I worry that other methodological issues may compound each other, not cancel each other out.
Map of Census tracts in Harris County, Texas.
Consider that:
Census tract population typically varies by up to 4X (2,000 to 8,000), according to the Census Bureau. This will produce deceptive spatial comparisons.
Some Census tracts may comprise dozens of square miles while others comprise a few city blocks. Typically, flood mitigation projects are not considered at the Census-tract level. According to three engineers I consulted, that’s too small in most cases to be workable.
Larger Census tracts may contain multiple watersheds, each with independent levels of risk – or individual watersheds with varying levels of risk. In such cases, the formula would average risk. But averaging can mask a serious problem in one area with a non-problem in another. Thus, the formula has a bias in favor of spatially smaller Census tracts. Smaller tracts tend to be more uniform in risk, so problems will likely stand out rather than get lost in an average. But in larger watersheds, flood risk will feather out with increased elevation and distance from a river. That will make it extremely difficult to calculate the number of people exposed to varying degrees of risk. Averaging takes the simple way out. But averaging risk is like comparing saints and sinners, then declaring “No problem.”
The data collection effort for the index omitsmany sources of funding. So the formula will calculate investment dollars from some entities and areas, but not others. For instance, the formula will NOT measure drainage funding from Harris County Commissioner Precincts, dozens of cities, and 389 municipal utility districts in unincorporated areas. The difficulty of data collection in these areas will produce another spatial bias. Likewise, the FMBI formula will omit the considerable drainage-improvement contributions of reputable private developers.
No one has tested how these inconsistencies will affect each other. But there’s an even bigger data integrity issue.
Partially Updated Data
HCFCD and its partners invested more than $1.5 billion in flood mitigation between Harvey and the end of 2021. Since 2000, they’ve invested more than $3.5 billion. But as of this writing, new MAAPnext flood maps only reflect the POST-mitigation risk associated with projects in FIVE bayous: Brays, Greens, White Oak, Sims, and Hunting. The Army Corps partnered with HCFCD in those.
Unfortunately, according to a knowledgeable source, HCFCD has not yet updated the risk maps for its own Capital Improvement Projects in other watersheds. So if you ran the allocation formula now, it would compare PRE-mitigation risk in 18 watersheds with POST-mitigation risk in 5.
Mitigation in those five watersheds totals $439 million out of $1.5 billion since Harvey. So true, current risk is reflected in only 29% of spending since Harvey and 13% in this century. Those percentages will no doubt increase in the future. But if you ran the numbers today, you would compare numbers with PRE- and POST-mitigation risk.
And consider this. With HCFCD spending at the current rate of about $80 million per quarter, “current risk” is a constantly changing target. So we’ll never be able to compare apples to apples in all watersheds anytime soon.
And we want to use this formula to guide future mitigation spending? Using it could send more money back to fix areas we already fixed!
Difficulty of Assigning Investments to Census Tracts
Another challenge: How do you determine which census tract(s) to apportion project benefits among? Example: Addicks and Barker Reservoirs. The Army Corps developed those back in the 1930s to protect downtown Houston…15-20 miles away!
Do you credit the investment to:
All of downtown?
People living inside the reservoirs (who have their own census tract)?
The current population of the entire Addicks and Barker Watersheds?
All census tracts along Buffalo Bayou and parts of White Oak Bayou, our second and third most populous watersheds?
And virtually all residents of the Addicks and Barker watersheds live upstream from the Corps’ investment, so they will not benefit from the investment either.
Downtown has immense commercial and economic value but relatively few permanent residents.
So, who gets the benefit? Again, lots of room for interpretation and misplaced assumptions here that numbers can easily mask! Now, multiply this problem times thousands of Census tracts.
Anti-Commercial Bias
The population-based FMBI has a built-in bias against commercial areas that have little to no residential population. For example, consider the cases of Downtown, the Texas Medical Center, and the Port of Houston. Such areas support employment throughout the region, but the formula discriminates against them by giving huge weight to population and omitting actual damage.
No Thresholds Defined
To my knowledge, the task force has never discussed threshhold “benefit” levels that correlate to “needs help” or “doesn’t need help.” The extremes may sometimes be easy to determine. But what about outcomes in the middle?
Offsetting Variables
Variables in the formula can offset each other as we saw above. In tight races for funding, who gets the next flood-mitigation investment? The area with the lowest investment, highest risk, or largest population? Such quandaries have not yet been addressed.
No Agreement on Weights of Other Factors
To help make future flood-mitigation decisions, proponents of the formula also suggest weighing (separately) other factors, such as the CDC’s Social Vulnerability Index. It includes the percentage of Low-to-Moderate residents in an area. However, no one has yet discussed the weight given the Benefit Index relative to other factors.
No Consideration of Actual Flood Damage
In deciding where to put flood mitigation projects, engineers traditionally look for damage clusters. It’s that simple. Dollars flow to damage.
Reducing flood damage is a tried and true, measurable way to evaluate projects. So why all the complexity?
What’s The Point?
What is this formula trying to prove? Is it attempting to develop a new approach to mitigation funding that eliminates a perceived bias in Benefit/Cost Ratios?
Commissioner Rodney Ellis often talks about how calculating the value of avoided damages in higher value homes disadvantages projects in poorer neighborhoods. That can be true in some instances. Expensive homes can ratchet up benefits (measured in dollars) faster than lower value homes can. And that can result in higher Benefit/Cost Ratios for projects in affluent neighborhoods – assuming density is held constant. But…
One high-value home on an acre would likely appraise less than an apartment building, also on an acre. In Kingwood, I compared the valuations of an expensive single-family home with a large apartment complex one block away. The appraised cost per acre (including structures) of the apartment complex is 4X higher.
Now consider that apartments accommodate almost half of Harris County’s population.
According to the latest census data, 54.9% of Harris County residents live in owner-occupied homes. The rest, 45.1 percent, live in apartments.
Most Americans aspire to and encourage home ownership, in part, because of the stability it fosters in communities. But this formula – because of its emphasis on population density – favors apartment areas over areas with owner-occupied homes. There’s nothing inherently wrong with that. You just need to understand what the formula does.
Difference Between Vertical and Horizontal Density
The Benefit Index favors all areas with dense population. Proponents argue that helping more people is better. I don’t argue with that. However, the generalization masks the financial pain inflicted by a flood on owners vs. renters, and on the people who live at ground level compared to those who live above it.
Ground floor renters may lose contents in a flood, but they won’t be responsible for making structural repairs. The owner will.
And many living above the ground floor may find themselves more inconvenienced by flooding than financially devastated. So, is it fair to count all people on all floors when determining who suffers the most pain?
Five-story apartment buildings crowding Brays Bayou with ground-level parking underneath. HCFCD has no way of knowing how many people live in apartments like this, yet HCFCD will be responsible for compiling the data.
In the proposed formula, higher population will lower the benefit index, making it look as though all renters (almost half the county’s population) suffered more than owners of single-family homes.
The premise underlying such “equity” arguments is that poor people can least afford floods. But most people in apartments like those shown above won’t make structural repairs as a homeowner would.
No Perfect Formula
No perfect formula exists that’s equally fair to all in all circumstances. That’s why FEMA, HUD and the Army Corps allow consideration of multiple factors when determining which projects to fund.
The Flood Mitigation Benefit Index focuses totally on population, risk, and past investment. It ignores actual flood damage.
If we use ANY formula to HELP allocate future flood-mitigation funds, we should all strive to:
Understand its built-in biases
Maintain high standards for data integrity.
If we want to test a hypothesis of historical discrimination in flood-mitigation funding, there’s a much simpler way. It’s called direct measurement. Simply locate damage centers from past storms and compare funding in the following decade designed to mitigate those areas.
For More Information
For more background on issues with the formula, see my earlier posts:
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/07/20210520-RJR_6978.jpg?fit=1200%2C800&ssl=18001200adminadmin2022-07-14 17:54:142022-07-14 21:58:06Inherent Bias and Limitations of Flood-Mitigation Benefit Index
The Houston-Galveston Area Council of Governments (H-GAC) has allocated $60 million to Montgomery County. The money comes out of a $488 million of Harvey flood-mitigation funds previously allocated to HGAC by the U.S. Department of Housing and Urban Development (HUD) through the Texas General Land Office (GLO). The $60 million is the single largest allocation to any governmental entity in the region out of the $488 million pot.
50% Committed to LMI Areas
At least 50% of the money must go to low-to-moderate income (LMI) areas in Montgomery County. The GLO has determined that MoCo plans meet HUD rules and conditionally approved the allocation.
However, things could still change and Montgomery County has not yet received the money.
According to H-GAC, the conditionally approved preliminary method of distribution (a plan for whom gets how much) is still pending acceptance by eligible entities and is subject to change through a published re-allocation process. A complete list of eligible activities is available in the Texas General Land Office (GLO) guidelines for the Regional Mitigation Program – Council of Governments Method of Distribution (COG MODs). Depending on changes, another 30-day public comment period may necessary, according to the GLO.
Where, How MoCo Will Spend the Money
I reached out to the Montgomery County Judge’s office to see how MoCo hopes to spend the money. Jason Millsaps replied, “Montgomery County will attempt several projects with these funds as soon as final approval has been granted.”
Millsaps continued, “In East County, we will work to de-snag, de-silt and remove vegetation that hinders flow from the Peach Creek, Caney Creek, White Oak Creek, and East Fork of the San Jacinto River. We will do the same for Lake Creek and Stewart Creek in Central/North County, with additional bank armor going in for Stewart Creek near the River Plantation Subdivision.”
Peak flows in the San Jacinto Watershed during Hurricane Harvey
Posted by Bob Rehak on 7/12/22
1778 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/07/20220712-Screen-Shot-2022-07-12-at-1.17.19-PM.jpg?fit=1200%2C729&ssl=17291200adminadmin2022-07-12 13:31:032022-07-12 13:46:36Montgomery County Allocated $60 Million in Harvey Mitigation Funds
At 2pm EDT on 7/11/22, the National Hurricane Center (NHC) issued an update that shows an area of concern offshore that stretches from Galveston Bay to the Florida Panhandle. NHC currently gives it a 30% chance of developing into something more serious in the next five days (10% in two days).
Area of low pressure sitting offshore on Monday afternoon at around 2PM.
Heavy Rain, Flash Flooding Likely East of Houston
This broad trough of low pressure is producing a large area of disorganized showers and thunderstorms. According to NHC, gradual development within this area of concern is possible if it can remain offshore while it meanders near the Gulf coast through the end of the week.
Regardless of development, heavy rains will be possible along portions of the northern Gulf coast from Louisiana to the Florida Panhandle over the next several days. For more information about the potential for heavy rain, see local National Weather Service forecasts and/or the Weather Prediction Center.
While the main danger from heavy rains currently lies to the east, global models are not yet unanimous in their forecasts. Jeff Lindner, Harris County Meteorologist says, “Global forecast models show some development of this trough into a closed area of low pressure mid- to late-week. Steering currents become very weak late week … with high pressure building into the Plains.” That will cause any tropical system over the northern Gulf to meander. Lindner added that the consensus among forecasters this morning kept any development well east of Houston.
Heat Records Fall Throughout Region
In the meantime, we could use a break from the blistering heat. Numerous records fell over the region yesterday.
College Station: 111 (exceeded July monthly record of 110 set in 1917)
BUSH IAH: 105 (exceeded daily record of 101 from 1998)
Hobby: 104 (exceeded daily record of 100 from 1964)
Galveston: 96 (tied daily record of 96 from 1931)
Posted by Bob Rehak on 7/11/2022
1777 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/07/two_atl_5d0.png?fit=900%2C665&ssl=1665900adminadmin2022-07-11 14:27:462022-07-11 19:10:39Offshore Area of Concern
