Drainage ditches in Colony Ridge appear to violate Liberty County drainage standards from both 2004 and 2019.
Both 2004 and 2019 regulations require developers to plant the slopes of ditches with grass to control erosion.
In addition, 2019 regulations require backslope interceptor swales, another erosion-control measure. These prevent stormwater from running down the sides of ditches.
According to residents, the developer has made little effort to do either or to bring older ditches up to current standards.
The violations contribute to sedimentation of the East Fork San Jacinto and its tributaries, and flooding from Lake Houston to Plum Grove.
Soil-Stabilization Violations
2004 Liberty County Road and Drainage Standards for Subdivisions and Development stipulate in Section 3.72 on Page 28 that, “All channels, and adjacent area, which has been disturbed by construction equipment shall be seeded with Bermuda grass or other grass as approved by the Precinct Commissioner or Designated Agent at the rate of eight pounds per acre (8 lb/ac). Seeding shall conform to Item 164 Seeding for Erosion Control of the “TxDOT Standards”.
Note erosion on sides of ditches. Colony Ridge 6/16/2020
2019 regulations also mandate additional erosion-control measures. The section on Erosion Control on page 100 states: “All drainage facilities must be designed and maintained in a manner which minimizes the potential for damage due to erosion. No bare earthen slopes will be allowed. Various slope treatments, including turf establishment, concrete slope paving, and rip-rap, are accepted. Flow velocities should be kept below permissible values for each type of slope treatment. Interceptor structures and backslope swale systems are required to prevent sheet flows from eroding the side slopes of open channels and detention facilities.” [Emphasis added.]
The emphasis on “All” and “maintained” would seem to require developers to bring all ditches up to the 2019 standard, but that clearly has not happened.
Colony Ridge 6/16/2020. Note severe erosion, lack of grass on slopes and absence of backslope interceptor swales.
What Backslope Swales Look Like
Liberty County regulations don’t provide schematics of backslope interceptor swales, but Harris County Flood Control regulations do. See below. At the top of the ditch embankment, a notch is cut into the horizontal area. This notch collects rain and channels it to a series of corrugated metal or HDPE drains that empty into the bottom of the channel. This prevents water from pouring over the banks of the channel and eroding them.
As you look at the pictures below, see if you can spot the:
Backslope swales (notches)?
Drain pipes?
Grass-lined banks?
You can’t. They aren’t there.
Colony Ridge 6/26/2020. Note severe erosion on banks. This ditch was built in 2015.Colony Ridge 6/26/2020Colony Ridge ditch draining into Maple Branch. 4/25/2019.Colony Ridge 6/14/2020 in newly developing area.
But construction technique does not seem to be the problem in Colony Ridge. They simply have not been built. That’s why erosion on the sides of the channels is so rampant.
Consequences of Erosion
All this eroded sediment has to go somewhere. And it did.
Between Kingwood and Huffman, the East Fork Mouth Bar downstream from Colony Ridge grew 4000 feet during Harvey and Imelda. Average water depth through this area decreased from 18 feet to 3 feet.
Colony Ridge isn’t 100% responsible for ALL this sedimentation. Natural erosion and sand mines also contributed. But substandard drainage practices in a 12-13,000 acre development had to play a large role.
The City of Houston is still dredging the West Fork Mouth Bar, more than three years after Harvey. Cost to taxpayers to date: more than $100 million. No one yet knows how much it will cost to remove the East Fork Mouth Bar.
Backslope interceptor swale on Taylor Gully in Harris County.12/4/2020Taylor Gully in Harris County 9/7/2020.
Posted by Bob Rehak on 12/5/2020
1194 Days since Hurricane Harvey and 453 since Imelda
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/2020/12/20200616-RJR_4085.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-12-05 20:47:342020-12-06 10:08:27Colony Ridge Ditches Violate Liberty County Drainage Standards
Twelve years ago, Hurricane Ike leveled the Bolivar Peninsula as it roared into Galveston Bay. Had Ike come onshore 10-20 miles west, Houston would be a very different place today. Most of Houston’s industrial might would have been on the dirty side of the storm instead of the dry side. Refineries, tank farms, and ships could have been destroyed with their chemicals poisoning the Bay. Ever since then, people and think tanks have advanced ideas to avoid such a possibility.
Park Would Protect Populated Areas in Larger Storms
While the Corps’ plan would reportedly protect the west side of Galveston Bay in a Category 1 or light Category 2 storm, critics worry that it wouldn’t be enough for a Cat 3, 4, or 5 storm. That’s where the Galveston Bay Park Plan comes in. It would form a natural barrier that helps protect industrial facilities from League City to Deer Park from storm surge driven into and across the Bay.
Recreational and Wildlife Potential
The Galveston Bay Park Plan would also create recreational opportunities for people within the Bay, while creating additional natural habitat for the area’s abundant birds, fish and shellfish.
Architects of Plan
The Severe Storm Prediction Education & Evacuation from Disaster (SPPEED) Center at Rice University conceived the plan and Rogers Partners of New York and Houston designed it.
Materials for Construction
The Park would be constructed by widening the Houston Ship Channel from its currently proposed 700 feet to 900 feet. The excavated clay will help build a 25-foot levee along the ship channel from Houston Point in Chambers County to the Texas City hurricane levee in Galveston County.
Additionally, with the disposal of the dredged material, the Galveston Bay Park Plan will create usable park space within Galveston Bay which will also include constructed wetlands as well as other bird habitats.
Award Winning Plan and Video
The GBPP was recently chosen as one of the top designs in the Houston 2020 Visions Competition. This competition sought creative ideas focused on making Houston more resilient.
According to Houston City Council Member David W. Robinson, FAIA, “This video is a must-watch for those concerned about the future of our region and the critical need for ongoing disaster preparedness. Hurricane storm surge is the sleeping giant of flood issues. This project is vitally necessary for our success in the 21st Century and will be a valuable asset for the region for many generations to come.”
Intro by Marvin Odum, former president of Shell Oil and Chief Harvey Recovery Officer for City of Houston
Recap of Ike that sets the stage for the plan
Description of the plan
The plan itself is almost too audacious to describe. You need to see it. Part 3 starts at 6:32 in and runs to 10:55.
The video was produced by filmmaker Jeffrey Mills of Io Communications of Houston. Barbara Mills provided animation and other special effects.
Posted by Bob Rehak on 12/4/2020
1194 Days since Hurricane Harvey and 12 years since Ike
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/12/Galveston-Bay-Park-Plan.jpg?fit=1200%2C669&ssl=16691200adminadmin2020-12-04 17:56:512020-12-04 17:59:42New Video Shows How Flood Protection Plan Would Transform Galveston Bay
Harris County Flood Control District (HCFCD) provided eight pages of detailed comments on it. HCFCD shared concerns expressed by the public about certain alternatives such as the widening of Buffalo Bayou. HCFCD also expressed that they hoped the Corps would not prematurely rule out some alternatives. The biggest: a flood tunnel.
HCFCD felt the Corps needed to put a sharper pencil to tunnel cost estimates and weigh those against the environmental impact/costs of widening Buffalo Bayou.
High-Level Concerns
Flood Control expressed six high-level concerns:
The Corps seemed to ignore a wealth of studies conducted by HCFCD on the study area and arrived at different conclusions.
The Interim Report presents benefits only in terms of annualized monetary values. “Water surface elevation reductions, numbers of structures benefitted, and the locations of benefits are curiously absent in the main report.” HCFCD believes some cost estimates should be revisited. “In particular, we believe the Interim Report overestimates stormwater tunnel costs and underestimates costs, both environmental and economic, of large-scale conveyance improvements to Buffalo Bayou.”
Estimated project costs are so high, and their benefit/cost ratios so low, that HCFCD anticipates funding challenges on both the federal and local levels. The 2018 Flood Bond did not allocate money for any of the alternatives proposed by the Corps. “However, smaller scales of the alternatives could be more affordable and acceptable to the public, and as a result, are more likely to be funded and implemented. These variations, both for structural and nonstructural alternatives, warrant more attention moving forward.”
The District recommends that “the full array of alternatives be consistently evaluated for environmental impacts, both beneficial and adverse. For example, we see opportunities for habitat restoration associated with the Addicks and Barker excavations…” But “…environmental impacts associated with the Buffalo Bayou channel improvement alternative are underestimated…” HCFCD believes that closer environmental inspection, right-of-way evaluation and public opposition, Buffalo Bayou expansion will not be deemed plausible.
The Corps’ report acknowledges that a non-structural alternative exists to improve water control operations at the existing reservoirs and to update the reservoir’s Water Control Manual. Unfortunately, the Corps does not elaborate much on these alternatives, but HCFCD believes “Operational changes could reduce the scale of alternatives necessary to achieve the desired level of resilience. Plus, modified operations alone could reduce flood risks and mitigate erosion and slope failures along Buffalo Bayou downstream of the reservoirs, both of which are problems that the study aims to address.”
Purchasing additional property upstream of the current reservoirs would require non-federal cost sharing. The Flood Control District questions the rationale for “commingling ownership responsibility with the Corps.” The District says, “We need to more fully understand why the Corps feels it is our responsibility to participate financially should this alternative move forward.”
Detailed Concerns
The report then goes into eight pages of amazingly detailed comments in a spreadsheet format. Most amount to requests for more information or clarification.
For instance:
Buffalo Bayou Widening: Costs vs. Benefits
“What are assumed costs for stream habitat loss associated with deepening Buffalo Bayou 11‐12 feet? How many acres of land would have to be acquired for this alternative, at what cost? How many parcels and/or structures? Please also summarize benefits of this alternative?”
HCFCD comments also include several suggestions:
Excavating Reservoirs: Way to Reduce Costs
Re: additional excavation of the Barker and Addicks reservoirs to increase their storage capacity, HCFCD said the following. “We feel there is an opportunity to further value engineer this alternative by stockpiling material within the reservoirs to create hills which will help limit haul costs.”
Tunnel Cost Estimates Too High; Need to be Weighed Against Tradeoffs
Re: the construction of tunnels to create an alternate route for floodwaters to Galveston Bay, HCFCD said this. “The tunnel cost is shown as $6.5B to $12B. This is significantly higher than estimates prepared during the District’s Phase 1 tunnel study…” The District estimated that a tunnel capable of conveying 10,000 cfs from the reservoirs to the Houston Ship Channel would cost $3 to $3.5 billion including a 50 percent contingency. That’s about a half to a third of the cost estimated by the Corps.
HCFCD fears that tunnels may have been prematurely eliminated from evaluation. Especially because environmental impacts associated with widening Buffalo Bayou were not considered in the decision to drop the tunnels from consideration.
Posted by Bob Rehak on 12/4/2020
1193 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/12/Buffalo-Bayou.jpg?fit=1200%2C1116&ssl=111161200adminadmin2020-12-04 13:27:262020-12-04 14:45:09HCFCD Raises Questions about Army Corps’ Buffalo Bayou Interim Report
Colony Ridge Ditches Violate Liberty County Drainage Standards
Drainage ditches in Colony Ridge appear to violate Liberty County drainage standards from both 2004 and 2019.
The violations contribute to sedimentation of the East Fork San Jacinto and its tributaries, and flooding from Lake Houston to Plum Grove.
Soil-Stabilization Violations
2004 Liberty County Road and Drainage Standards for Subdivisions and Development stipulate in Section 3.72 on Page 28 that, “All channels, and adjacent area, which has been disturbed by construction equipment shall be seeded with Bermuda grass or other grass as approved by the Precinct Commissioner or Designated Agent at the rate of eight pounds per acre (8 lb/ac). Seeding shall conform to Item 164 Seeding for Erosion Control of the “TxDOT Standards”.
Liberty County’s Subdivision and Development Regulations, revised January 2019 contain the identical language on slope stabilization. See Section 40.9.11 Channel Excavation (Page 91).
Backslope Interceptor Swale Requirement
2019 regulations also mandate additional erosion-control measures. The section on Erosion Control on page 100 states: “All drainage facilities must be designed and maintained in a manner which minimizes the potential for damage due to erosion. No bare earthen slopes will be allowed. Various slope treatments, including turf establishment, concrete slope paving, and rip-rap, are accepted. Flow velocities should be kept below permissible values for each type of slope treatment. Interceptor structures and backslope swale systems are required to prevent sheet flows from eroding the side slopes of open channels and detention facilities.” [Emphasis added.]
What Backslope Swales Look Like
Liberty County regulations don’t provide schematics of backslope interceptor swales, but Harris County Flood Control regulations do. See below. At the top of the ditch embankment, a notch is cut into the horizontal area. This notch collects rain and channels it to a series of corrugated metal or HDPE drains that empty into the bottom of the channel. This prevents water from pouring over the banks of the channel and eroding them.
Stark Contrast Between Regulations and Reality
As you look at the pictures below, see if you can spot the:
You can’t. They aren’t there.
Properly constructed backslope interceptor swales constitute a best management practice (BMP). They can prevent the type of erosion you see above. This educational PowerPoint explains how these structures work as well as the dangers of not building them correctly.
But construction technique does not seem to be the problem in Colony Ridge. They simply have not been built. That’s why erosion on the sides of the channels is so rampant.
Consequences of Erosion
All this eroded sediment has to go somewhere. And it did.
Colony Ridge isn’t 100% responsible for ALL this sedimentation. Natural erosion and sand mines also contributed. But substandard drainage practices in a 12-13,000 acre development had to play a large role.
The City of Houston is still dredging the West Fork Mouth Bar, more than three years after Harvey. Cost to taxpayers to date: more than $100 million. No one yet knows how much it will cost to remove the East Fork Mouth Bar.
Plum Grove residents have also documented clogged streams and bayous that they say have contributed to local flooding. Plum Grove is suing the developer. The TCEQ found construction practices bad enough to affect human health.
It seems like prevention would be more effective than correction.
The Right Way
Ironically, Harris County has regulations similar to Liberty County’s that govern construction of drainage ditches. But the results are much different when and where people actually follow the regulations. See below.
Posted by Bob Rehak on 12/5/2020
1194 Days since Hurricane Harvey and 453 since Imelda
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.
New Video Shows How Flood Protection Plan Would Transform Galveston Bay
Twelve years ago, Hurricane Ike leveled the Bolivar Peninsula as it roared into Galveston Bay. Had Ike come onshore 10-20 miles west, Houston would be a very different place today. Most of Houston’s industrial might would have been on the dirty side of the storm instead of the dry side. Refineries, tank farms, and ships could have been destroyed with their chemicals poisoning the Bay. Ever since then, people and think tanks have advanced ideas to avoid such a possibility.
Park Would Protect Populated Areas in Larger Storms
One of the most novel and affordable is a complement to the Army Corps’ Coastal Protection Study. It’s called the Galveston Bay Park Project.
While the Corps’ plan would reportedly protect the west side of Galveston Bay in a Category 1 or light Category 2 storm, critics worry that it wouldn’t be enough for a Cat 3, 4, or 5 storm. That’s where the Galveston Bay Park Plan comes in. It would form a natural barrier that helps protect industrial facilities from League City to Deer Park from storm surge driven into and across the Bay.
Recreational and Wildlife Potential
Architects of Plan
The Severe Storm Prediction Education & Evacuation from Disaster (SPPEED) Center at Rice University conceived the plan and Rogers Partners of New York and Houston designed it.
Materials for Construction
The Park would be constructed by widening the Houston Ship Channel from its currently proposed 700 feet to 900 feet. The excavated clay will help build a 25-foot levee along the ship channel from Houston Point in Chambers County to the Texas City hurricane levee in Galveston County.
Additionally, with the disposal of the dredged material, the Galveston Bay Park Plan will create usable park space within Galveston Bay which will also include constructed wetlands as well as other bird habitats.
Award Winning Plan and Video
The GBPP was recently chosen as one of the top designs in the Houston 2020 Visions Competition. This competition sought creative ideas focused on making Houston more resilient.
According to Houston City Council Member David W. Robinson, FAIA, “This video is a must-watch for those concerned about the future of our region and the critical need for ongoing disaster preparedness. Hurricane storm surge is the sleeping giant of flood issues. This project is vitally necessary for our success in the 21st Century and will be a valuable asset for the region for many generations to come.”
View the video here. It’s divided up into three segments:
The plan itself is almost too audacious to describe. You need to see it. Part 3 starts at 6:32 in and runs to 10:55.
The video was produced by filmmaker Jeffrey Mills of Io Communications of Houston. Barbara Mills provided animation and other special effects.
Posted by Bob Rehak on 12/4/2020
1194 Days since Hurricane Harvey and 12 years since Ike
HCFCD Raises Questions about Army Corps’ Buffalo Bayou Interim Report
In October, I reported on the Army Corps’ 210-page Buffalo Bayou and Tributaries Resiliency Study (BBTRS) Interim Report.
Harris County Flood Control District (HCFCD) provided eight pages of detailed comments on it. HCFCD shared concerns expressed by the public about certain alternatives such as the widening of Buffalo Bayou. HCFCD also expressed that they hoped the Corps would not prematurely rule out some alternatives. The biggest: a flood tunnel.
High-Level Concerns
Flood Control expressed six high-level concerns:
Detailed Concerns
The report then goes into eight pages of amazingly detailed comments in a spreadsheet format. Most amount to requests for more information or clarification.
For instance:
Buffalo Bayou Widening: Costs vs. Benefits
“What are assumed costs for stream habitat loss associated with deepening Buffalo Bayou 11‐12 feet? How many acres of land would have to be acquired for this alternative, at what cost? How many parcels and/or structures? Please also summarize benefits of this alternative?”
HCFCD comments also include several suggestions:
Excavating Reservoirs: Way to Reduce Costs
Re: additional excavation of the Barker and Addicks reservoirs to increase their storage capacity, HCFCD said the following. “We feel there is an opportunity to further value engineer this alternative by stockpiling material within the reservoirs to create hills which will help limit haul costs.”
Tunnel Cost Estimates Too High; Need to be Weighed Against Tradeoffs
Re: the construction of tunnels to create an alternate route for floodwaters to Galveston Bay, HCFCD said this. “The tunnel cost is shown as $6.5B to $12B. This is significantly higher than estimates prepared during the District’s Phase 1 tunnel study…” The District estimated that a tunnel capable of conveying 10,000 cfs from the reservoirs to the Houston Ship Channel would cost $3 to $3.5 billion including a 50 percent contingency. That’s about a half to a third of the cost estimated by the Corps.
HCFCD fears that tunnels may have been prematurely eliminated from evaluation. Especially because environmental impacts associated with widening Buffalo Bayou were not considered in the decision to drop the tunnels from consideration.
Posted by Bob Rehak on 12/4/2020
1193 Days after Hurricane Harvey