City of Houston (COH) Public Works Department held a kick-off meeting with contractors and the Bear Branch Trail Association (BBTA) this morning for the Tree Lane Bridge Rehabilitation Project. Public Works and the contractors outlined plans for the project. They also discussed access through BBTA property and safety protocols.
Chris Bloch (left) and Lee Danner (center) of BBTA met with contractor and Houston Public Works representatives at bridge on 2/21/24.
Construction should begin by mid-March and take approximately 150 days.
Project Scope
The $909,000 project will involve:
Creating access areas for equipment
Removing all existing concrete under the bridge and along the sidewalls
Establishing a 2-foot deep by 32-foot-wide low-flow channel from 20 feet upstream to 20 feet downstream of the bridge
Contractors will meet with the Bear Branch Elementary School principal to understand normal drop-off and pick-up times. They will then work around those times to try to minimize traffic interference.
Regardless, the City urged parents to warn children to stay away from the construction zone, which will be on both sides of the bridge. Lots of heavy equipment will be maneuvering in tight spaces with limited visibility near Bear Branch Elementary. Observe all traffic warnings and flag men.
Reason for Project
Embankments under the bridge have degraded significantly in the last 10 years. This is largely because of jetting.
Jetting is caused when water backs up behind a bridge that is too small for the volume of water coming down a stream. Pressure upstream of the bridge forces turbulent water to shoot out the downstream side destroying anything in its way. See six images below taken 2/21/24.
Looking upstream at eastern side of bridge.Jetting has blown out concrete under the bridge.Damaged storm sewer outfall. Exposed abutment Downcutting as floodwater tries to make more room for itself.Jetting continues to erode a large basin south of the bridge.Note how narrow creek is upstream (Left). Right = effect of jettingdownstream.
It Wasn’t Always This Way
The erosion has started in the last ten years and accelerated with upstream development.
In general, developments increase the time of accumulation of runoff. Compared to a densely developed area, when rain falls on a forest, it trickles its way to the creek. But if it falls on concrete and rooftops, it rushes to the creeks through storm sewers.
For illustration purposes, the graph below shows the actual change along Brays Bayou.
Change in time of accumulation in Brays Bayou as watershed developed over 85 years.
If development were sufficiently mitigated, post-development runoff would be no higher than pre-development. But given the amount of recent erosion, some development upstream from Tree Lane is likely insufficiently mitigated.
I’ve lived near the Tree Lane Bridge for 40 years. For the first 30, erosion was no problem. Now look at it. Compare the two satellite images below.
In 2014, you could barely see creek.Same area in 2023.
Chris Bloch, an engineer, says that at the time of Imelda in 2019, the open space under the bridge was 500 square feet. The design approved by COH and Harris County Flood Control District will add approximately 64 square feet in the form of a low-flow channel. Contractors will add that where the stream has already downcut.
If the 500 SF estimate is accurate, another 64 SF would represent a 12.8% increase in the carrying capacity of the channel under the bridge.
The state of the bridge now is worse than it was after Imelda, BEFORE the last repair job. And no storms since Imelda have even came close to Imelda’s magnitude. That means insufficiently mitigated development may have played a role in building flood peaks faster and higher; and undermining the bridge.
So, will 12.8% be enough to eliminate more jetting? Only time will tell. Keep your fingers and toes crossed.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/02/20240221-DJI_0037.jpg?fit=1100%2C733&ssl=17331100adminadmin2024-02-21 17:59:342024-02-22 14:46:06CoH Public Works Kicks Off Tree Lane Bridge Rehab Project
Entergy power poles sit on City of Houston (COH) rights-of-way. The company also runs underground wires in an easement near US59. Yet after years of discussion, the company still has not moved them to make room for the widening of Northpark Drive. Nor did the company comply with a request by the City to say how it would move them by a March 8th deadline.
The Northpark project is intended, in part, to create an all-weather evacuation route for 78,000 people who live in the Kingwood area. Rising floodwaters during Hurricane Harvey cut off escape routes along Hamblen Road, Kingwood Drive, and West Lake Houston Parkway.
Offending Entergy poles where Northpark will be widened for turn lanes next to the bridge over UP railroad tracks.
So, COH put Entergy on notice. It wrote a letter, discussed in last week’s LHRA board meeting, that was dated 2/6/24. The letter requested Entergy to submit a proposed scheduleand plan by last Friday detailing how it would relocate its facilities within 30 days.
That letter was dated 2/6/24, meaning the equipment should be moved and out of the way by 3/8/24.
Entergy Response Contained Only Hypothetical Schedule
ReduceFlooding.com has learned that Entergy replied to COH Public Works by last Friday as requested. But the reply did not indicate how they would move their equipment by 3/8/24. Nor did it address why Entergy could not meet the 30-day deadline or why the company has taken no action since 2020.
Instead the response suggested Entergy needed many more months, but committed to no firm deadline, according to a COH spokesperson.
Entergy and LHRA had already worked through potential conflicts with other utilities. So, resolving conflicts was not the issue.
I do not have a copy of the Entergy letter to reprint at this time; an Entergy spokesperson refused to provide it, citing potential legal concerns. As a result of the Entergy letter, LHRA has now asked to meet with the City Attorney.
Cost Escalation Possible
Continued delays are escalating the stakes. The Lake Houston Redevelopment Authority (LHRA), which is acting as an agent of the City, has costly contractual obligations to its contractors.
Given the rate of inflation, delays could also reduce the purchasing power of LHRA’s budget. In the last four years, inflation in the construction sector has totaled 15-20%. And this project costs more than $75 million. Yet the original budget included only $3 million for change orders.
A legal battle could take years to resolve. That could needlessly put lives at risk and inconvenience tens of thousands of people daily.
Entergy Motive, Next Steps Unclear
It’s not clear what Entergy – a $4 billion company in Texas alone – hopes to gain through continued delays.
In the past, Entergy asked for compensation to move its poles. But according to an LHRA spokesperson, compensation is not allowable under Texas law because the poles were in a City right of way and not covered by an easement. Thus, any payment would have constituted a “gift of public funds,” which the Texas Constitution prohibits.
Entergy was, however, legally entitled to compensation for moving buried wires in an easement near the Exxon station at US59. Entergy had agreed to move them for $711,000.
Then, within days after the disagreement about payment for relocating the poles, Entergy’s asking price to move the underground wires mysteriously increased by half a million dollars. Simultaneously, their cost estimate went from line item to lump sum – without itemization. Since then, the asking price has increased another $200,000 without explanation.
LHRA has asked to meet with the City Attorney to discuss options and next steps. More news to follow.
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/2024/02/20240113-RJR_3079.jpg?fit=1100%2C733&ssl=17331100adminadmin2024-02-20 09:51:222024-02-27 11:27:37Entergy Escalates Battle with COH over Northpark
At the abandoned Williams Brothers sand mine on the San Jacinto West Fork, a strip of land – approximately 400 to 500 feet long and up to 50 feet wide – collapsed into the river during the flood in late January.
The dramatic erosion, during a relatively minor (2-5-year) rain event, dramatizes the destructive power of moving water and the need for greater setbacks from the river for sand mines. It also raises questions about abandonment plans for sand mines.
Resident Photo From Boat Shows Collapse
A resident who frequently boats the river and wishes to remain anonymous supplied the picture below. As the resident said, “All that dirt went somewhere. And it didn’t go upstream.”
Looking upstreamadjacent to Williams Brothers Mine south of Kingwood Drive
Aerial Shots Show Extent of Damage
From the air, the same location looks like this.
Williams Brothers Mine on right. Eagle Sorters Mine top left. Note extent of fresh sand on left.Same area from lower angle. Note how trees collapsed into river.Note also how erosion has eaten half of maintenance road around mine.
Where Trees Once Stood
Compare that with the satellite image below from Google Earth taken last year. Note how there used to be a row of trees on each side of the road. Now, trees remain only on one side.
The measuring tool Google Earth shows the width of the eroded strip was approximately 50 feet.
Most of the trees on the river side of the road are now floating down the river somewhere.
Blankets of Fresh Sand Everywhere
The resident who took the first shot above (the one from the boat) has lived near the river for 40 years. He says he’s never seen so much fresh sand deposited in a flood. See below.
Fresh sand flanks both side of the West Fork.Note trail of trees in water.
The images above show the power of moving water. One cubic foot of fresh water weighs 62.4 pounds. And more than 20,000 cubic feet per second moved down this reach of the West Fork during the peak of the January flood. That’s a lot of force on sandy soil.
We Must Plan for River Migration
That force was magnified by the way a river meanders. On the outside of curves, water accelerates. That extra speed accelerates erosion and creates what geologists call the cut bank.
Conversely, water travels less far and slower on the inside of a curve. As a result, sand is often deposited there in what geologists call point bars. Learn more in this post about Why Rivers Move.
Over time, erosion on one side of a river and deposition on another tends to exaggerate curves. Geologists call that process river migration. River migration already broke through the dike of one sand mine slightly upstream.
During the January flood, water flushing through that mine likely contributed to the buildup of sand blocking the Northpark drainage ditch near Northpark Woods.
Looking upriver along West Fork. Red arrow indicated where West Fork migrated through dike of abandoned sand mine.
Note in the photo above that the Northpark Ditch is now blocked by sand higher than ditch itself. This blockage suddenly appeared during the Jan. ’24 flood. It is backing water up toward Northpark Woods and Oakhurst in the upper right. At least some of the sand was likely flushed out through the breach in the dike above.
Need Greater Setbacks from the River For Sand Mines
As I stated in the beginning, this dramatizes the need for greater setbacks from the river for sand mines. At one time, there was no minimum distance.
In November 2021, after years of work by Bill McCabe and the Lake Houston Flood Prevention Initiative, TCEQ adopted new Best Management Practices (BMPs) for sand mining in the San Jacinto River Basin.
The new rules specify “A minimum 100-foot buffer zone is required adjacent to perennial streams greater than 20 feet wide, 50 feet for perennial streams less than 20 feet wide, and 35 feet for intermittent streams.”
Clearly, that may not be enough. For a list of what other states specify, see the Sand Mining page of ReduceFlooding.com.
Posted by Bob Rehak on 2/27/2024
2363 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/02/20240216-FullSizeRender.jpg?fit=1100%2C619&ssl=16191100adminadmin2024-02-17 18:29:392024-02-22 08:52:58River Bank Collapses, Taking Half of Sand Mine Road
CoH Public Works Kicks Off Tree Lane Bridge Rehab Project
City of Houston (COH) Public Works Department held a kick-off meeting with contractors and the Bear Branch Trail Association (BBTA) this morning for the Tree Lane Bridge Rehabilitation Project. Public Works and the contractors outlined plans for the project. They also discussed access through BBTA property and safety protocols.
Construction should begin by mid-March and take approximately 150 days.
Project Scope
The $909,000 project will involve:
See the construction plans here.
Safety Warning
Contractors will meet with the Bear Branch Elementary School principal to understand normal drop-off and pick-up times. They will then work around those times to try to minimize traffic interference.
Regardless, the City urged parents to warn children to stay away from the construction zone, which will be on both sides of the bridge. Lots of heavy equipment will be maneuvering in tight spaces with limited visibility near Bear Branch Elementary. Observe all traffic warnings and flag men.
Reason for Project
Embankments under the bridge have degraded significantly in the last 10 years. This is largely because of jetting.
Jetting is caused when water backs up behind a bridge that is too small for the volume of water coming down a stream. Pressure upstream of the bridge forces turbulent water to shoot out the downstream side destroying anything in its way. See six images below taken 2/21/24.
It Wasn’t Always This Way
The erosion has started in the last ten years and accelerated with upstream development.
In general, developments increase the time of accumulation of runoff. Compared to a densely developed area, when rain falls on a forest, it trickles its way to the creek. But if it falls on concrete and rooftops, it rushes to the creeks through storm sewers.
For illustration purposes, the graph below shows the actual change along Brays Bayou.
If development were sufficiently mitigated, post-development runoff would be no higher than pre-development. But given the amount of recent erosion, some development upstream from Tree Lane is likely insufficiently mitigated.
I’ve lived near the Tree Lane Bridge for 40 years. For the first 30, erosion was no problem. Now look at it. Compare the two satellite images below.
Chris Bloch, an engineer, says that at the time of Imelda in 2019, the open space under the bridge was 500 square feet. The design approved by COH and Harris County Flood Control District will add approximately 64 square feet in the form of a low-flow channel. Contractors will add that where the stream has already downcut.
If the 500 SF estimate is accurate, another 64 SF would represent a 12.8% increase in the carrying capacity of the channel under the bridge.
Will It Be Enough Conveyance?
This will be the second time in three years that the city has repaired the bridge and its embankments.
The state of the bridge now is worse than it was after Imelda, BEFORE the last repair job. And no storms since Imelda have even came close to Imelda’s magnitude. That means insufficiently mitigated development may have played a role in building flood peaks faster and higher; and undermining the bridge.
So, will 12.8% be enough to eliminate more jetting? Only time will tell. Keep your fingers and toes crossed.
Sign Up for Project Updates
You can sign up for project updates by visiting Houston Public Works’ “Engage Houston” page for this project.
Posted by Bob Rehak on 2/21/24
2367 Days since Hurricane Harvey
Entergy Escalates Battle with COH over Northpark
Entergy power poles sit on City of Houston (COH) rights-of-way. The company also runs underground wires in an easement near US59. Yet after years of discussion, the company still has not moved them to make room for the widening of Northpark Drive. Nor did the company comply with a request by the City to say how it would move them by a March 8th deadline.
The Northpark project is intended, in part, to create an all-weather evacuation route for 78,000 people who live in the Kingwood area. Rising floodwaters during Hurricane Harvey cut off escape routes along Hamblen Road, Kingwood Drive, and West Lake Houston Parkway.
First Notified in 2020 and Still No Action
On 2/10/24, I detailed how Entergy was first notified about the project in 2020. Yet the company has moved nothing along Northpark to make room for construction. Groundbreaking for the project was last April and construction began last July.
So, COH put Entergy on notice. It wrote a letter, discussed in last week’s LHRA board meeting, that was dated 2/6/24. The letter requested Entergy to submit a proposed schedule and plan by last Friday detailing how it would relocate its facilities within 30 days.
Entergy Response Contained Only Hypothetical Schedule
ReduceFlooding.com has learned that Entergy replied to COH Public Works by last Friday as requested. But the reply did not indicate how they would move their equipment by 3/8/24. Nor did it address why Entergy could not meet the 30-day deadline or why the company has taken no action since 2020.
Instead the response suggested Entergy needed many more months, but committed to no firm deadline, according to a COH spokesperson.
Entergy and LHRA had already worked through potential conflicts with other utilities. So, resolving conflicts was not the issue.
I do not have a copy of the Entergy letter to reprint at this time; an Entergy spokesperson refused to provide it, citing potential legal concerns. As a result of the Entergy letter, LHRA has now asked to meet with the City Attorney.
Cost Escalation Possible
Continued delays are escalating the stakes. The Lake Houston Redevelopment Authority (LHRA), which is acting as an agent of the City, has costly contractual obligations to its contractors.
Given the rate of inflation, delays could also reduce the purchasing power of LHRA’s budget. In the last four years, inflation in the construction sector has totaled 15-20%. And this project costs more than $75 million. Yet the original budget included only $3 million for change orders.
A legal battle could take years to resolve. That could needlessly put lives at risk and inconvenience tens of thousands of people daily.
Entergy Motive, Next Steps Unclear
It’s not clear what Entergy – a $4 billion company in Texas alone – hopes to gain through continued delays.
In the past, Entergy asked for compensation to move its poles. But according to an LHRA spokesperson, compensation is not allowable under Texas law because the poles were in a City right of way and not covered by an easement. Thus, any payment would have constituted a “gift of public funds,” which the Texas Constitution prohibits.
Entergy was, however, legally entitled to compensation for moving buried wires in an easement near the Exxon station at US59. Entergy had agreed to move them for $711,000.
Then, within days after the disagreement about payment for relocating the poles, Entergy’s asking price to move the underground wires mysteriously increased by half a million dollars. Simultaneously, their cost estimate went from line item to lump sum – without itemization. Since then, the asking price has increased another $200,000 without explanation.
LHRA has asked to meet with the City Attorney to discuss options and next steps. More news to follow.
For More Information
For more information about the project including construction plans, visit the project pages of the LHRA/Tirz 10 website. Or see these posts on ReduceFlooding:
Posted by Bob Rehak on 2/20/2024
2365 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.
River Bank Collapses, Taking Half of Sand Mine Road
At the abandoned Williams Brothers sand mine on the San Jacinto West Fork, a strip of land – approximately 400 to 500 feet long and up to 50 feet wide – collapsed into the river during the flood in late January.
The dramatic erosion, during a relatively minor (2-5-year) rain event, dramatizes the destructive power of moving water and the need for greater setbacks from the river for sand mines. It also raises questions about abandonment plans for sand mines.
Resident Photo From Boat Shows Collapse
A resident who frequently boats the river and wishes to remain anonymous supplied the picture below. As the resident said, “All that dirt went somewhere. And it didn’t go upstream.”
Aerial Shots Show Extent of Damage
From the air, the same location looks like this.
Where Trees Once Stood
Compare that with the satellite image below from Google Earth taken last year. Note how there used to be a row of trees on each side of the road. Now, trees remain only on one side.
Most of the trees on the river side of the road are now floating down the river somewhere.
Blankets of Fresh Sand Everywhere
The resident who took the first shot above (the one from the boat) has lived near the river for 40 years. He says he’s never seen so much fresh sand deposited in a flood. See below.
The images above show the power of moving water. One cubic foot of fresh water weighs 62.4 pounds. And more than 20,000 cubic feet per second moved down this reach of the West Fork during the peak of the January flood. That’s a lot of force on sandy soil.
We Must Plan for River Migration
That force was magnified by the way a river meanders. On the outside of curves, water accelerates. That extra speed accelerates erosion and creates what geologists call the cut bank.
Conversely, water travels less far and slower on the inside of a curve. As a result, sand is often deposited there in what geologists call point bars. Learn more in this post about Why Rivers Move.
Over time, erosion on one side of a river and deposition on another tends to exaggerate curves. Geologists call that process river migration. River migration already broke through the dike of one sand mine slightly upstream.
During the January flood, water flushing through that mine likely contributed to the buildup of sand blocking the Northpark drainage ditch near Northpark Woods.
Note in the photo above that the Northpark Ditch is now blocked by sand higher than ditch itself. This blockage suddenly appeared during the Jan. ’24 flood. It is backing water up toward Northpark Woods and Oakhurst in the upper right. At least some of the sand was likely flushed out through the breach in the dike above.
Need Greater Setbacks from the River For Sand Mines
As I stated in the beginning, this dramatizes the need for greater setbacks from the river for sand mines. At one time, there was no minimum distance.
In November 2021, after years of work by Bill McCabe and the Lake Houston Flood Prevention Initiative, TCEQ adopted new Best Management Practices (BMPs) for sand mining in the San Jacinto River Basin.
The new rules specify “A minimum 100-foot buffer zone is required adjacent to perennial streams greater than 20 feet wide, 50 feet for perennial streams less than 20 feet wide, and 35 feet for intermittent streams.”
Clearly, that may not be enough. For a list of what other states specify, see the Sand Mining page of ReduceFlooding.com.
Posted by Bob Rehak on 2/27/2024
2363 Days since Hurricane Harvey