Last week, the City of Houston started clearing debris from the culverts under Kingwood Drive near Kingwood High School. Local flood-fighter Chris Bloch has been working for years behind the scenes to document drainage issues such as this one and convince local officials to address them.
Un-named and Long-Forgotten Tributary Finally Getting Attention
One of Bloch’s latest investigations has been an uncatalogued and long-ignored channel under Kingwood Drive. It helps drain Kingwood High School into Bens Branch. But it doesn’t show up anywhere on Harris County Flood Control District maps.
Two Feet of Sediment Block Culverts Under Kingwood Drive
Bloch says, “The channel originates at Kingwood High School’s athletic fields. The ditch is narrow and full of sediment and vegetation. Side channels, which empty into this ditch, are also full of sediment and vegetation. This is the only ditch providing storm water drainage from the high school campus.”
The ditch in question passes through three culverts under the Westbound lanes of Kingwood Drive. They are obstructed by 24 inches of sediment and debris. See below.
“If cleared of sediment, the cross section area of the three culverts would total 60 square feet.“
More Blockages Downstream
After crossing under Kingwood Drive, the ditch funnels water into a 24-inch corrugated plastic culvert. That carries it across the Kingwood Country Club Driving Range. “This cross-sectional flow area of this culvert is only about 5% of the total area of the three culverts that pass under Kingwood Drive,” says Bloch.
Later, as the ditch crosses two fairways on its way to Bens Branch, sediment and vegetation again partially block it. They also partially block the three culverts under Centerpoint’s easement near Bens Branch.
Bloch believes, “Maintenance and improvement of this ditch upstream of these outfalls would significantly improve drainage of the high school campus.”
Ensuring Long-Term Maintenance
“Although the Harris County Flood Control District (HCFCD) has no property rights for this channel, the District may be willing to partner with property owners to improve drainage,” says Bloch. “The original channel was reported to have been installed by Humble ISD (HISD) prior to the existence of the driving range.”
Bloch says he has been communicating with HISD, HCFCD and the City of Houston about the poor condition of this ditch since 2020. “I recently communicated with Mayor Pro Tem Martin’s office about this ditch and spoke with Mayor Pro Tem Martin himself about it. The de-silting is another small step forward for flood mitigation in Kingwood. I appreciate the involvement of Mayor Pro Tem Martin.”
“Recently, HCFCD indicated they would be willing to partner with the property owners of this ditch to improve drainage. Hopefully, once the City completes the sediment removal of the channel on the Kingwood Drive right of way, HISD and the Country Club can get together with the HCFCD to improve drainage across the Country Club property to Bens Branch,” says Bloch.
Posted by Bob Rehak with thanks to Chris Bloch and Mayor Pro Tem Dave Martin
1650 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/03/20220306-Screen-Shot-2022-03-06-at-3.41.40-PM.jpg?fit=1200%2C799&ssl=17991200adminadmin2022-03-06 16:49:082022-03-06 16:49:11City De-Silting Channel Under Kingwood Drive Near High School
Last week, Harris County Flood Control District (HCFCD) began mobilizing for the restoration of the Ben’s Branch drainage ditch between Kingwood Drive and Rocky Woods. The work will involve removing accumulated sediment that has diminished the conveyance capacity of the ditch.
Engineers measure conveyance in terms of “level of service.” A 100-year level of service means that a ditch will convey a 100-year rain without overflowing. The Kingwood Drainage Analysis performed last year by HCFCD revealed that sediment had reduced the conveyance of Ben’s Branch to a 2-year level of service in places. This project will restore the ditch to its original contours.
Importance of Project
Along Ben’s Branch, as a result of flooding during Harvey:
Kingwood High School immediately to the west of this project flooded badly. The building suffered $67 million in damages. The school lost another $10 million in contents. Four thousand students had to be bused to another school for seven months.
Homes along both sides of the ditch flooded.
All four shopping centers in Kingwood’s Town Center flooded. Many businesses still have not returned.
Thirteen people died, included twelve seniors at Kingwood Village Estates. Six died from injuries sustained during evacuation and six from stress-related illnesses after returning and finding their homes destroyed.
History of Previous Ben’s Branch Projects since Harvey
For the current work between Kingwood Drive and Rocky Woods, HCFCD will start at the downstream end and work its way north. The work should take about five months. It involves removing more than 22,000 cubic yards of sediment, restoring the original banks of the ditch, and replacing a number of outfall pipes that have become blocked or damaged over time.
Once the work begins in earnest, HCFCD contractors will enter the northern side of the project at the end of Cedar Knolls and move south toward Kingwood Drive. There, they will exit the project behind the old H-E-B store. Crews will work around Kingwood High School start/stop times to reduce traffic snarls.
HCFCD considers this a maintenance project, not a capital-improvement project.
Expansion of the Diversion Ditch that runs from the new St. Martha Church down to Deer Ridge and River Grove Parks where it eventually enters the West Fork. The purpose of the Diversion Ditch project: to further reduce the flow of water into Ben’s Branch.
A project to reduce flooding along Taylor Gully. Two options have been discussed:
Widening and deepening Taylor Gully itself
Establishing a regional detention pond on the land owned by Perry Homes’ subsidiary Figure Four Partners.
HCFCD has not announced a timetable yet for either of those projects. Any work on Taylor Gully would depend on whether Harris County and the City are able to negotiate the purchase of Woodridge Village from Perry. Woodridge Village is the aborted development that twice flooded Elm Grove and North Kingwood Forest Villages in 2019.
Posted by Bob Rehak on 2/3/2021
1253 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/02/20210131-DJI_0151-1.jpg?fit=1200%2C900&ssl=19001200adminadmin2021-02-02 14:29:012021-02-04 14:47:14Mobilization Begins for Next Phase of Ben’s Branch Restoration
Harris County Flood Control District (HCFCD) will begin repairing the next section of Ben’s Branch on January 19. The repairs will take place in the channel between Kingwood Drive and the natural portion of Ben’s Branch at the end of Rocky Woods Drive.
Jose Predraza of Stuart Consulting is coordinating the project. He said, “The purpose of this project is to restore the conveyance of Ben’s Branch. It has been reduced over the years due to erosion and sedimentation. The project will include implementing erosion repairs, repairing side slope failures, repairing or replacing outfalls, rectifying flow lines, and removing excess sediment.”
Contractors will remove approximately 22,000 cubic yards of sediment deposited by floods over the years.
Continual cycles of deposition and erosion have clogged, deformed and narrowed the creek.
The Kingwood Area Drainage Analysis showed that Ben’s Branch had been reduced to a 2-year level of service in places. That means, it will flood in a 2-year rain.
“Erosion repairs include the placement of fill material, placement of 3”x5” granular fill, and the placement of grade #1 riprap,” continued Pedraza. “Channel cross sections will be reconstructed with a maximum 5:1 (H:V) slope where necessary. This project will be conducted wholly within the existing channel right-of-way.”
Pedraza estimates construction will last 145 days – not quite five months. If weather cooperates, contractors should complete the work in early June.
Then, geotechnical investigations led to additional design time.
Finally, getting approval to cross CenterPoint’s power-line easement took additional time.
Trucks do not have enough room to turn around within the work area, so one-way traffic will be the rule. Trucks will enter the work area by coming up Woods Estates Drive to Cedar Knolls and entering the greenbelt from there. They will then follow the Centerpoint easement to the work area. Finally, they will exit by going south toward Kingwood Drive, cutting across the ditch, and coming out behind the old H-E-B.
Contractors will then haul the excavated dirt to nearby TCEQ-approved landfill sites outside of the .02% annual chance (500-year) flood plain.
Daily schedules are being coordinated with Kingwood High School start/stop times to reduce traffic congestion and improve safety.
Benefitting Residents, Schools and Businesses
When complete, the creek will be able to handle much more water than before without coming out of its banks…as much as it could when Friendswood originally excavated it.
This will be a vast improvement, especially for those who live near the creek in Kings Forest and Bear Branch, many of whom flooded during Harvey.
The work should reduce the flood risk for Kingwood High School also. The school first flooded in 1994. During Harvey, the building flooded to the second floor. It suffered $67 million dollars in damages and lost another $10 million in contents. The Humble ISD had to close Kingwood High for seven months and bus kids to another high school where they alternated “shifts” with the students from that high school.
Kingwood High also flooded during Imelda, but had less damage.
Finally, the work will also benefit the shopping center on the northwest corner of Kingwood Drive and West Lake Houston Parkway. Every store in the center flooded badly during Harvey. Many businesses still have not returned. The center nearly flooded again during Imelda. Water flowed through the parking lot and was inches from coming into stores.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/01/20210108-DJI_0030.jpg?fit=1200%2C900&ssl=19001200adminadmin2021-01-08 14:09:272021-01-08 14:09:30HCFCD Will Begin More Work on Ben’s Branch Starting January 19
The objective: to restore conveyance of Ben’s Branch and reduce potential for flooding in Kings Forest, Bear Branch, the Kingwood High School, and Kingwood Town Center.
Sediment has restricted the flow of the channel gradually during the last three decades. It now contributes to flooding.
During Harvey, many homes on both sides of the stream flooded. Many also flooded again during Imelda.
Walking along the creek today, the first thing one notices is a craggy channel with sides that seem to have slumped into the stream. Flood control surveys, however, show that is not the case. The channel filled with sediment. Then the stream eroded down again through the accumulated sediment.
Continual cycles of deposition and erosion have clogged, deformed and narrowed the creek.
Approximately 15,000 Cubic Yards of Sediment To Be Removed
Getting the channel back to its original state will require removal of approximately 15,000 cubic yards of sediment. However, engineers have not yet determined the exact number.
The scope of work will include replacement of damaged drain pipes that carry water to the ditch.
The job is still in its planning stages. Actual dirt work should begin sometime in October.
Downstream, the project will stop at Kingwood Drive. Note below how the channel under the Kingwood Drive bridge is virtually twice as large as the channel in the foreground.
When complete, this project should make the channel north of Kingwood Drive as wide as it is south of Kingwood Drive. It’s all about getting the channel back to its designed carrying capacity.
An exact timetable for the project is not yet available, but it will take several months.
Posted by Bob Rehak on 9/4/2020
1102 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/09/BB-Start-Stop.jpg?fit=1914%2C1404&ssl=114041914adminadmin2020-09-04 18:31:132020-09-04 18:43:03HCFCD to Begin Next Phase of Ben’s Branch Clean Out in October
Disclaimer: I spent the better part of a day driving down every street that borders Ben’s Branch. I saw damage clustered in three areas. It’s possible other areas were affected but the City had removed trash before I got there.
At least two schools, 7 homes, and one business flooded along Ben’s Branch in Kingwood during Imelda. All were located near choke points along the creek. And massive recent upstream development likely played a role in each case. That new development also played a role in eroding the margin of safety between floodwaters and foundations all along the creek – even for homes and businesses that did not flood. Total damages will likely exceed $3 million along Ben’s Branch in Kingwood.
Ben’s Branch Now and 10 Years Ago: Influence of Upstream Development
Imelda Tested Design Limits of Drainage Systems
Most drainage systems are designed to protect homes and businesses from a hundred-year flood. Imelda was a hundred year flood. The storm tested the design limits of flood infrastructure everywhere along Ben’s Branch in Kingwood.
Based on its peak intensity of 4.56 inches in one hour (as measured at the US59/West Fork gage), Imelda qualified as a 100-year storm. Streets, storm drains and ditches are designed to handle that much as an upper limit. And for the most part they did. Especially because builders usually elevate most structures at least two feet above the hundred-year flood plain.
Those extra two feet act as a margin of safety and as a hedge against future upstream development.
Limits Exceeded in Several Places During Imelda
In each case where homes, businesses or schools flooded along Ben’s Branch, unique circumstances eliminated that margin of error and resulted in flooded structures.
With the exception of one low-lying home I found in Hunter’s Ridge very close to the creek, all of the structural damage took place at three choke points along the creek.
Choke Point #1: Northpark and Ben’s Branch
Where Ben’s Branch crosses under Northpark Drive, two things happen. A ditch from the new Woodridge Forest subdivision joins it. And then all that water is forced into a culvert that crosses under Northpark Drive.
To my knowledge, no one has ever upgraded that culvert despite significant upstream development. It backs water up for several blocks during heavy rains and forces water OVER Northpark Drive. This caused at least six homes near Aspen Glade west of Hidden Pines to flood.
When water backed up and flowed over Northpark, it cut off both inbound and outbound traffic. It also broke through the fences of homes that back up to Northpark.
Impact of New Development
Net: the flooding of homes on Aspen Glade was likely caused by an undersized culvert at North Park that could not convey all the water coming from hundreds of acres of new development. When the water backed up, it rushed over North Park for approximately two blocks. Eyewitness reports and FaceBook videos peg the height at a foot above the roadway.
Much of the drainage from the new development joined Ben’s Branch just before it reached the culverts.
Choke Point #2: Woodland Hills Drive and Ben’s Branch
About two or three blocks east of the culverts under Northpark, between St. Martha Catholic School and Kids in Action, Ben’s Branch narrows down again. It quickly funnels from a wide, excavated ditch to a narrow stream cutting through dense forest. See photo below.
At this choke point, both the school and Kids in Action, flooded. Repairing the school after the May flood cost St. Martha $900,000. Repairing Kids in Action cost $500,000. This time it will cost each even more.
The results were costly. St. Martha’s lost two classroom buildings plus its playground.
Until the school buildings can be dried, disinfected and rebuilt, classes are being held on upper floors and in other parish buildings. No children were ever endangered by the flood. Parish personnel started evacuations to higher buildings as soon was water started coming into the parking lot, the lowest point on the campus.
Across the creek, Kids in Action, one of Kingwood’s most popular day care and after school facilities, had its own problems.
Haven’s spent $500,000 repairing her facilities after the May 7th flood. That’s a lot for a small business. She’s determined to weather this storm, too. But she worries that some of her clients may grow impatient in the inconvenience during repairs.
Choke Point #3: Kingwood Drive and Ben’s Branch
As Ben’s Branch approaches Kingwood Drive from the northwest, it spreads out into a 100+ acre forested area that includes the Creekwood Nature Center. But just before it crosses under Kingwood Drive, Ben’s Branch’s flood plain funnels down between Kingwood High School and the old H-E-B shopping center. At that point, a second branch of the stream joins it from the north. After crossing under Kingwood Drive, it is further constricted on the east side by commercial development. This represents another choke point.
The Kingwood High School gym and natatorium took on several inches of water during Imelda when drains and/or Ben’s Branch backed up. Merchants in the old H-E-B shopping center also report being stranded in their stores for two hours at the peak of Imelda as water from Ben’s Branch raced through the parking lot. Merchants said the water was inches from coming in their stores.
While many of the businesses south of Kingwood Drive in Town Center and Kings Harbor reported having water lapping at their foundations, I found none that reported flood damage.
No Simple Fix
I can’t think of a simple fix to all of three of these problems. Fixing one could compound the others. For instance, it would be simple to replace the culverts under Northpark with a bridge when the street is widened. However, that would just increase the volume of water backing up where the creek narrows between St. Martha’s School and Kids in Action. That would likely flood them even worse.
Channelizing the creek all the way to Kingwood Drive would likely be unpalatable from a political point of view. Four reasons: Few people in that area were affected. They all love their greenbelts. And the costs would be high. That would make the Benefit/Cost ratio of the project a non-starter.
One Possible Solution
One possible solution: convert the unused land around St. Martha’s new church north of Northpark Drive to additional detention. That’s valuable land and detention is expensive, but it may be a better alternative than losing the school which was just expanded in 2008. Father TJ Dolce is pitching that idea and hopes the Archdiocese would approve the use of their vacant land for detention. The big question: Would it be enough to make a difference.
Ben’s Branch may affect fewer structures. But it probably affects more people when you add up enrolled students and their families.
Posted by Bob Rehak on 10/1/2019with help from Father TJ Dolce, Diane Havens, Lela Yorba, Daryl Palmer and National Helicopter Service.
763 Days since Hurricane Harvey and 12 since Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/09/Flooded-Building.jpg?fit=1024%2C768&ssl=17681024adminadmin2019-09-30 22:48:212019-10-01 22:33:30Imelda Floods Ben’s Branch Schools, Homes at Three Choke Points