The Lake Houston Gates Project is moving closer to reality with breakthroughs on the benefit/cost ratio, funding and endorsements.
City of Houston Mayor Pro Tem Dave Martin and Chief Recovery Officer Stephen Costello provided updates on 2/27/23 at City Hall on the Lake Houston Gates Project. The wide-ranging, hour-long discussion covered several related topics. They included:
A critical path for construction
Dredging of the lake
Funding for gates and dredging
Several related engineering studies
A favorable ruling from FEMA on the Benefit-Cost Ratio
An endorsement to the area’s legislators by the Greater Houston Partnership.
Need For Gates
For those new to the area, the City of Houston has been pushing to add gates to the Lake Houston Dam ever since Harvey in 2017. Upstream, Lake Conroe’s gates can release 150,000 cubic feet per second (CFS). But Lake Houston’s can only release 10,000 CFS.
The disparity in discharge capacity complicates joint-reservoir-management and pre-release strategies designed to avoid flooding by reducing the water level in Lake Houston.
Lake Houston releases cannot keep up with Lake Conroe’s. And pre-releasing water from Lake Houston takes so long that storms can veer away during the lowering process, often resulting in wasted water. That’s an important consideration for a water-supply lake.
According to Martin and Costello, the gate project will:
• Serve as the first phase of a long-term effort to extend the life of the Dam • Enable the rapid lowering of lake levels in advance of a flood • Eliminate the need for a seasonal lowering of both Lake Houston and Lake Conroe • Provide potential water-rights savings • Protect an estimated 5,000 residential properties in the surrounding area • Yield an estimated half billion dollars in economic benefits during the life of the project
However, the City discarded that idea as “too risky” after further study. The engineering company cautioned the City that it would have a difficult time finding contractors willing to risk modifying a 70-year old concrete dam. The potential liability was just too great. So the City then revisited adding various numbers of tainter gates to the eastern, earthen portion of the dam.
Because tainter gates exceeded FEMA’s funding, the City had initially focused on crest gates. But after investigating the safety issues, the City decided to seek more funding for tainter gates instead.
Recommended location for new tainter gates is next to old ones, not farther east as I conjectured earlier.
The picture below is slightly wider and shows more of how both halves of the dam come together.
If funding comes through, new gates would go in the upper right along the earthen portion of the dam, next to the old gates.
Funding Needs
FEMA initially set aside $50 million for the gates. Plus Harris County committed $20 million in the 2018 Flood Bond to attract FEMA’s match. But the latest construction estimates show eleven tainter gates could cost between $200 and $250 million.
After engineering and environmental studies, only $68.3 million in funding remains. That includes an earmark secured by Congressman Dan Crenshaw. So the City is seeking another $150 million from the State of Texas. Martin and Costello have made weekly trips to Austin so far during this session to line up support from legislators, committee chairs, and the Texas Division of Emergency Management.
Social Benefits Improve Benefit/Cost Ratio
All this is suddenly possible because of a favorable ruling from FEMA on the benefit-cost ratio (BCR).
For years, Houston had struggled to get the BCR for the gate project above 1.0 (the point at which benefits exceed costs). Usually, FEMA strictly interprets benefits as “avoided damages to structures.”
But Houston Mayor Sylvester Turner and Costello met with FEMA to argue that the problem was much bigger than damaged structures.
As a result, FEMA allowed the City to add the value of “social benefits” to the BCR. Social benefits can include such things as avoiding lost wages when businesses are destroyed; transportation disruptions that reduce the region’s productivity; reducing negative impacts on student achievement when schools are disrupted; and more.
The social-benefit ruling covers a number of City projects, not just the gates. It should also benefit other areas, especially rural ones.
Said Costello, “The minute the social benefits came in, everything was great.” Instead of struggling to reach 1.0, the City is now far above it.
Greater Houston Partnership Endorsement
With that out of the way, the Greater Houston Partnership wrote a powerful letter to state legislators seeking their support for the gate project. See below.
The Partnership includes business leaders from 900 member companies in the 12-county Houston Region.
Dredging Update
While pressing ahead with the gates project, the City is also working on a long-term dredging plan for the lake and working with the SJRA on sedimentation and sand-trap pilot projects.
The lake has already lost more than 20,000 acre feet of capacity due to sedimentation. That worsens flooding. While the Federal Government supports efforts to improve Lake Houston now, the chances of getting more money in the future will be reduced – unless we can show that we’re at least keeping pace with annual sediment deposits.
Since Harvey, FEMA, the Army Corps, TWDB, and City of Houston have removed almost 4 million cubic yards of material from the lake at a cost of $226 million.
We have to prevent more sediment from coming downstream or dredge it after it gets here.
Stephen Costello, City of Houston Chief Recovery Officer
The City is currently lobbying for another $50 million for maintenance dredging to add to the money secured in the last legislative session by now-retired State Representative Dan Huberty. New Representative Charles Cunningham will reportedly now carry that banner forward along with State Senator Brandon Creighton.
Legislative News to Follow
March 10th is the last day to file bills in the Texas Legislature this year. Please visit the legislation page on ReduceFlooding.com for updates once bills are filed and start moving forward in Austin.
Thanks to all of our elected and appointed representatives who have pushed so hard on so many fronts for the last 2008 days to tie all the pieces of this complicated flood-mitigation puzzle together.
Posted by Bob Rehak on 2/27/2023
2008 Days since Hurricane Harvey
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Tomorrow is the fifth anniversary of Hurricane Harvey. Many in the Lake Houston Area have asked, “Are we safer now?” The answer is yes, but we have a long way to go to achieve all our goals. Here’s a five-year flood-mitigation report card. It describes what we have and haven’t accomplished in 29 areas. So get ready for a roller coaster ride. I’ll leave the letter grades to you.
Lake Houston Area Mitigation
1) Dredging
The most visible accomplishment in the Lake Houston Area since Harvey is dredging. The City and Army Corps removed approximately 4 million cubic yards of sediment blocking the West and East Forks. Before dredging, River Grove Park flooded six times in two months. Since dredging, it hasn’t flooded once to my knowledge.
West Fork mouth bar after Harvey and before dredging. Now gone, but not forgotten.
Potential location for new tainter gates east of the spillway portion of the dam (out of frame to the right.
3) Upstream Detention
To reduce the amount of water coming inbound during storms, the San Jacinto River Basin Master Drainage Study identified 16 potential areas for building large stormwater detention basins. Unfortunately, they had a combined cost of $3.3 billion and would only reduce damages by about a quarter of that.
So, the SJRA recommended additional study on the two with the highest Benefit/Cost Ratio. Their hope: to reduce costs further. The two are on Birch and Walnut Creeks, two tributaries of Spring Creek near Waller County. Expect a draft report in February next year.
Funding these would likely require State assistance. But the Texas Water Development Board’s San Jacinto Regional Flood Planning Group has just recently submitted its first draft report. The draft also recommended looking at detention basin projects on West Fork/Lake Creek, East Fork/Winters Bayou, and East Fork/Peach Creek.
Building them all could hold back a foot of stormwater falling across 337 square miles. But funds would still need to be approved over several years. We’re still a long way off. Results – on the ground – could take years if not decades.
4) “Benching”
The Regional Flood Planning Group also recommended something called “benching” in two places along 5 miles of the West Fork. In flood mitigation, benching entails shaving down a floodplain to create extra floodwater storage capacity. Like the detention basins, benching is still a long way off…if it happens at all.
5) West Fork Channel Widening
Finally, the Regional Flood Planning Group recommended widening 5.7 miles of the West Fork to create more conveyance. But again, at this point it’s just a recommendation in a draft plan.
San Jacinto River Authority
6) SJRA Board Composition
After Harvey, many downstream residents accused SJRA of flooding downstream areas to save homes around Lake Conroe. At the time, SJRA’s board had no residents from the Humble/Kingwood Area. So Governor Abbott appointed two: Kaaren Cambio and Mark Micheletti. Cambio later resigned due to a potential conflict of interest when she took a job with Congressman Dan Crenshaw. That leaves Micheletti as the lone Humble/Kingwood Area resident on a seven-person board. However, the SJRA points out that the Board’s current president, Ronnie Anderson, represents Chambers County, which is also downstream.
State Representative Will Metcalf, who represents the Lake Conroe area, introduced a bill to limit SJRA board membership to upstream residents. Luckily for downstream residents, it failed.
7) Lake Conroe Lowering
SJRA identified temporary, seasonal lowering of Lake Conroe as a strategy to reduce downstream flood risk until completion of dredging and gates projects in the Lake Houston Area. The lowering creates extra storage in the lake during peak rainy seasons. After SJRA implemented the plan, Lake Conroe residents objected to the inconvenience. They sued SJRA and the City, but lost. After discussion with all stakeholders, the SJRA quietly modified its plan. It still lowers the lake, but not as much.
8) Lowering Lake Houston
Houston also started lowering Lake Houston, not seasonally, but in advance of major storms. The City has lowered the lake more than 20 times since beginning the program. That has helped to avoid much potential flooding to date.
9) Lake Conroe Dam Management
SJRA applied for and received several TWDB grants to enhance flood mitigation and communications in the San Jacinto River Basin. One involves developing a Lake Conroe Reservoir Forecasting Tool. SJRA has also worked with San Jacinto County to develop a Flood Early Warning System.
Finally, SJRA’s Lake Conroe/Lake Houston Joint Reservoir Operations Plan is on hold pending completion of the City’s plan to add more gates to the Lake Houston dam. Such projects may help reduce the risk of releasing unnecessarily large volumes of water in the future.
However, the location is controversial. Geologists say it wouldn’t reduce sediment in the area of greatest damage. Environmentalists worry that it could increase sedimentation through a “hungry-water” effect and open the door to river mining. And I worry that, even if successful, the pilot study would not be extendable. That’s because it relies on partnerships with sand miners. And other tributaries to Lake Houston do not have sand mines or as many sand mines.
Sand bar blocking West Fork after Harvey. The Corps has since removed it.
Federal Funding
It’s hard to get good grades on your flood mitigation report card without funding.
$1.6 million for HCFCD for Taylor Gully stormwater channel improvement.
$1.6 million for HCFCD for Kingwood Diversion Channel improvement.
$1.67 million for Harris County for the Forest Manor drainage improvement project in Huffman.
$8.2 million from FEMA the Westador Basin stormwater detention project on Cypress Creek.
$9.9 million from FEMA for the TC Jester storm water detention basin on Cypress Creek.
Crenshaw also has backed community requests for more funding in Fiscal 23. They include:
$8 million for the Lake Houston Dam Spillway (Gates).
$10 million for the Woodridge Stormwater Detention Basin (see below).
$10 million for a Cedar Bayou Stormwater Detention Basin.
Harris County Flood Control
19) Channel Maintenance and Repair
Harris County Flood Control has already completed several maintenance projects in the Lake Houston Area. In Kingwood, those projects include Taylor Gully, Ben’s Branch, parts of the Diversion Ditch and other unnamed ditches. In Atascocita, HCFCD also completed a project on Rogers Gully. Upstream, HCFCD is working on the third round of repairs to Cypress Creek. Batch 3 includes work at 12 sites on 11 channel sections. I’m sure the District has maintenance projects in other areas, too. I just can’t name them all.
Bens Branch near Kingwood High School after sediment removal.
In 2019, uncontrolled stormwater from the Woodridge Village development twice flooded approximately 600 homes in Elm Grove Village and North Kingwood Forest. HCFCD and the City purchased Woodridge from Perry Homes last year. HCFCD soon thereafter started removing sediment from the site to create a sixth stormwater detention basin that would more than double capacity on the site. At the end of last month, contractors had removed approximately 50,000 cubic yards out of 500,000 in the contract. This gives HCFCD a head start on excavation while engineers complete the basin’s final design.
21) Local Drainage Study Implementation
HCFCD authorized four studies of the drainage needs in the Lake Houston Area. They completed the Huffman and Kingwood studies. Atascocita and East Lake Houston/Crosby started earlier this year and are still underway.
The Kingwood study measured levels of service in all channels and outlined strategies to improve them to the 100-year level. The first two projects recommended: Taylor Gully and the Kingwood Diversion Ditch. Neither has started construction yet. But see the notes under funding above.
The Huffman Study recommended improvements to FM2100, which TxDOT will handle. It also recommended dredging in the East Fork near Luce Bayou which the City has completed. Finally, it recommended a bypass channel for Luce. However, pushback from residents forced cancellation of that project.
22) Buyouts
HCFCD completed buyouts of 80+ townhomes on Timberline and Marina Drives in Forest Cove last month. Contractors demolished the final run-down complex in August. That should improve property values in Forest Cove.
Completion of demolition of one of the last Forest Cove Townhome Complexes in July 2022.
23) Regulation Harmonization
Harris County Flood Control and Engineering have been working to get municipalities and other counties throughout the region to adopt certain minimum drainage regulations. I discussed the importance of uniformly high standards in last night’s post. So far, about a third of the governments have upgraded their regs. A third are still deciding whether to act. And the remainder have taken no action. There has been little movement in the last six months.
City of Houston
As mentioned above, the City has taken a lead role in dredging, adding gates to Lake Houston, and proactive lake lowering. In addition, the City has helped with:
24) Bridge Underpass Clean-Out
The City of Houston successfully cleaned out ditches under Kingwood Drive and North Park Drive in at least six places. Bridges represent a major choke point during floods. So eliminating sediment buildups helps reduce flood risk in areas that previously flooded.
Excavation of Bens Branch under Kingwood Drive by City crews.
The lowest score on the flood-mitigation report card probably goes to LSGCD.
26) Subsidence
The Lone Star Groundwater Conservation District has started pumping groundwater again at an alarming rate. Projected subsidence near the Montgomery County Border equals 3.25 feet, but only 1 foot at the Lake Houston dam. That could eventually tilt the lake back toward the Humble/Kingwood/Huffman area and reduce the margin of safety in flooding. That’s bad news.
Sand Mining Regulations
Twenty square miles of West Fork sand mines immediately upstream from I-69 have exposed a swath of floodplain once covered by trees to heavy erosion during floods. Mathematically, the potential for erosion increased 33X compared to the normal width of the river. Sand mines were also frequently observed releasing sediment into the river. And the dikes around the mines often wash out.
So in 2019, the Lake Houston Area Grassroots Flood Prevention Initiative (LHAGFPI) began meeting with legislators, regulators and the Texas Aggregate and Concrete Association (TACA). The goal: to establish comprehensive Best Management Practices (BMPs) for the sand mining industry in the San Jacinto River Basin.
27) Mine Plan/Stabilization Reports Now Required
TCEQ adopted new regulations, effective January 6, 2022. They required miners to file a ‘Mine Plan’ by July 6, 2022 and also a ‘Final Stabilization Report’ when a mine is played out.
28) Vegetated Buffer Zones (Setbacks)
The new regs also stipulate undisturbed vegetative buffer zones around new mines. Buffer zones aid in sediment filtration and removal by slowing surface water. They also strengthen dikes.
The new regs require a minimum 100-foot vegetated buffer zone adjacent to perennial streams greater than 20 feet in width. However, for streams less than 20 feet wide, the buffer zone is only 50 feet for perennial streams, and 35 feet for intermittent streams.
29) Reclamation Bonds
Unfortunately, the Flood Prevention Initiative could not convince TCEQ to require ‘reclamation bonds.’ Other states use such bonds to prevent miners from abandoning mines without taking steps to reduce future erosion, such as planting vegetation.
My apologies to any projects or parties I omitted. Now it’s your turn. Give grades to those you think have done the best job on YOUR Harvey flood-mitigation report card.
Posted by Bob Rehak on 8/26/22
1823 Days since Hurricane Harvey and one day from Harvey’s Fifth Anniversary
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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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Lake Conroe Association contended that the SJRA’s lake lowering policy amounted to a “taking” of residents’ property.
The City of Houston and SJRA contended that the water at issue did not belong to lakefront homeowners. It belonged to the State of Texas and the City. Therefore, the Lake Conroe Association had no basis for a “takings” claim.
Sources close to the process said that before the matter was heard on appeal, the LCA realized it would never win. So its leaders decided to drop the case and avoid more legal fees.
Clearing the Way for Lake-Lowering Policy to Remain in Effect
This reduces chances of another devastating release that floods downstream residents during a major storm, such as Hurricane Harvey. The SJRA released 79,000 cubic feet per second during Harvey, one third of all the water coming down the West Fork between Humble and Kingwood.
2022 Version of Lake-Lowering Policy is a Compromise
Over time, the SJRA has reduced the amount of lowering in its policy. Currently, the spring lowering is one-half foot below 201 during April and May, the level of the conservation pool in the lake. Originally, it was one full foot below 201. Most people call that the “normal” level. However, the mean level of Lake Conroe is below that about two-thirds of the time. (See last table below.)
Current Lake Conroe Level
Evaporation and low rainfall currently have Lake Conroe at 200.8, or about 3 inches above the new seasonal target level and 3 inches below the conservation pool.
Currently Lake Conroe’s level is at 200.8 feet and the City of Houston (COH) has not called to lower the lake further.
A close reading of the policy reveals that for the lake lowering to begin, the City of Houston must call for the water.
Below-Average Rainfall Has Delayed Need for Spring Release
However, below-average rainfall for the last two months has delayed the need for a spring release from Lake Conroe this year. Much of the state is now in drought.
Montgomery and northern Harris Counties are currently rated as “abnormally dry.”Southern Harris, Fort Bend and Waller Counties all have “moderate drought.”
Jace Houston, general manager of the SJRA, said, “We haven’t had a big rain in a long time and there’s no significant rain in the foreseeable future. The feeling is that evaporation will soon take the lake down to the target level. The City of Houston must initiate the lowering. If we get a lot of rain, we’ll start releasing again.”
Time for Healing
In addition to reducing the spring lake lowering, the 2022 policy lowers Lake Conroe to 200.5 in August and 200 in September – both a half foot higher than the original policy.
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McCabe has given ReduceFlooding.com permission to reproduce his letter. See below.
To the SJRA:
Thank you very much for the opportunity to respond to the Sand Trap Study you have formulated. I think your initial work is excellent and commend you on your data gathering. However, there are a few points I would like you to consider before proceeding.
As you know, my group worked very hard with TCEQ to establish Best Management Practices (BMPs) for Sand Miners in the San Jacinto watershed. This Rulemaking was approved in early 2022 and incorporated into 30 TAC Chapter 311, Subchapter J. Also approved was corresponding Regulatory Guidance document RG 555, implementing the BMP Rules.
Key Provision: Undisturbed Buffer Zones
A key provision of the Regulatory Guidance is:
“2.1.1 Vegetative Buffer Zones Vegetative buffer zones are continuous undisturbed or planted vegetated areas that surround a development, or land disturbance activity, or that border an intermittent stream or permanent water body. Buffer zones aid in sediment filtration and removal by slowing surface water flow through these areas. Disperse construction site runoff over the entire buffer zone if possible. 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. Measure buffer zones from the stream bank to the nearest area of disturbance at the site.”
Study Recommendation is “Counterintuitive”
We had fought very hard to establish these buffer zones (at one time we had proposed buffer zones of 1,500 feet). The very essence of this provision was to KEEP the miners out of the San Jacinto riverbed. Now to go back and allow in-stream mining seems counter-intuitive to me.
Legal Complications of Waiving Buffer Zone
Additionally, I am not certain how you would get this buffer zone condition waived. HB 1824 issues a waiver per the Parks and Wildlife Code, Sec. 86.017. However, it does not address TCEQ regulation at 30 TAC Chapter 311(J), which was implemented AFTER HB 1824 was passed. You need to have your staff look at the interaction between the two conflicting provisions.
More Holistic Approach Needed
Before proceeding, I would suggest looking closely at Bob Rehak’s Holistic approach to reducing sedimentation, as outlined in one of his recent articles:
Revegetating riverbanks
Dredging more often where the sand builds up near the mouth of the West Fork
Dredging a channel through the mouth bar area
Reinforcing sand-mine dikes to withstand floods
Leaving more natural green space between mines and the river
Moving sand mine stockpiles out of floodway/floodplain areas
William McCabe, Lake Houston Area Grassroots Flood Prevention Initiative
If you have questions or comments on the SJRA’s Sediment Trap Proposal, please submit them via email to: floodmanagementdivision@sjra.net.
Deadline: No later than April 29, 2022
Posted by Bob Rehak on 4/15/22 based on a letter by Bill McCabe, Chairman of the Lake Houston Area Flood Prevention Initiative
1690 Days since Hurricane Harvey
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The Bayou Land Conservancy has added its voice to those raising concerns about the SJRA’s sand trap proposal for the San Jacinto River watershed. The pilot project began out of a desire to reduce sediment buildup in the mouth bar of the West Fork. But it has morphed into something very different – a trench through a sand bar more than 12 miles upstream.
Sand bar on West Fork San Jacinto that would be used for pilot project outside Hallett mine. Note that the height of the freshly deposited sand is engulfing several medium sized trees. This location is downstream from several other large mines.Picture taken shortly after Harvey.
The study did not address what should be the main goal of sediment removal: excessive deposition in the area of the mouth bar downstream of US 59.
Managing mouth bar sediment deposition, and related flooding, should be kept at the forefront as this project moves forward.
Sand mining in the floodplain of the San Jacinto West Fork between 1995 and 2017 virtually quadrupled. More than 30% of the river’s flood plain is now being mined. That’s a huge problem that requires other types of solutions to reduce sedimentation from mines, such as improved Best Management Practices.
The group also suggested a need for greater oversight of sand mining by state regulators. It feels an inconsistency exists between in-stream mining via sand traps and the TCEQ’s newly adopted BMPs for sand mining.
BLC’s Specific Concerns re: Recommendation
BLC then went on to discuss the specific recommendation – rock-lined trenches through sand bars outside of sand mines. They listed three concerns:
“River migration and erosion: Changes in river course, including erosion and deposition of sediment, are naturally occurring processes. Installation of hardscape or mechanical features within the flowing part of the river will have an impact on this natural process and could lead to increased erosion in the area surrounding the facility, increased sediment transport downstream, and destabilization of the stream to the detriment of the surrounding and downstream communities.”
“Water quality: 85% of the drinking water needs of the Houston metropolitan region are met by Lake Houston, at the receiving end of the San Jacinto River. Instead of occasional turbidity increase during dredging of the mouth bar, sand trapping could create a long-term elevation in turbidity leading to increased water treatment costs for the entire region, transferring the cost to the public from private interests. Additionally, the riverbed contains chemical components that may need to be addressed in water treatment at additional public expense.”
“Accountability: the governing legislation created by HB1824 does not address the question of accountability should the private interest in the sediment trap fail to protect the public’s interest or go out of business without remediating the in-stream mining facility.”
More Study Recommended Before Implementation
BLC also recommended that two of the study’s recommendations deserve to be prioritized and expanded to provide as much accurate data as possible before sand-traps get further consideration:
“Evaluate total annual sediment load transported to Lake Houston, including the area downstream of proposed sediment traps, and compare to anticipated trapped sediment loads.”
“Perform further geomorphic assessment to address potential downstream instabilities due to removing sediment and to determine appropriate sediment removal volumes.”
BLC went on to encourage SJRA to extensively study the holistic sediment story of the upper San Jacinto River watershed. Previous studies point to Spring and Cypress Creeks as major contributors of sediment. BLC wants the sediment loads in those creeks studied as well as the areas downstream of the proposed sand traps.
The group continued, “A science-based, peer-reviewed, methodology of assessing the sediment budget of the watershed is imperativebefore assuming that removing sediment from any single location on the river will have a positive impact on mouth bar deposition. … Without a basis for understanding the sediment budget for the West Fork, it’s impossible to evaluate (or approve) this project.”
Rivers in Texas Are Public Property
BLC also pointed out that even though HB1824 exempted SJRA and Harris County Flood Control District from any requirement to obtain a permit, pay a fee, or purchase the material taken, in Texas the contents of a river belong to the citizens of the state. “Therefore we all have an interest in the results of this in-stream mining proposal,” said the group’s letter.
The letter concluded, “BLC recommends that extensive further study be undertaken to determine if in-stream mining, i.e. sand traps, will accomplish the stated goal of providing a long-term solution for managing the mouth bar deposition, without creating further instability to the river system and negative impacts to the surrounding and downstream communities.“
The Bayou Land Conservancy, one of the leading environmental groups in the Lake Houston watershed, preserves land along streams for flood control, clean water, and wildlife.
How Taking Sediment Out of a River Can Increase Erosion
Non-technical people may have trouble understanding how taking sediment out of a river can increase erosion. Basically, if you take too much out (more than the natural baseline of dissolved sediment), it can create a “hungry water” effect. Many academics have documented the hungry water effect. It’s especially noticeable downstream of dams, which are notorious for trapping sediment. Rivers with excess sediment transport capacity tend to erode their banks and streamed to compensate.
Posted by Bob Rehak on 4/9/2022based on a Bayou Land Conservancy letter to SJRA
1684 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/03/2.WestForkAndSandMines.jpg?fit=2000%2C1333&ssl=113332000adminadmin2022-04-09 18:18:552022-04-09 18:57:06Bayou Land Conservancy Raises Concerns About SJRA Sand Trap Proposal
The San Jacinto River Authority (SJRA) recently completed a 246-page conceptual design study, in partnership with the Harris County Flood Control District, that explored the feasibility of implementing sediment trapping facilities (“sand traps”). The purpose: to remove sediment from the West or East Fork of the San Jacinto River. The results and findings of this study have been documented in an engineering report entitled “San Jacinto River and Tributaries Sediment Removal and Sand Trap Development.”
Prior to proceeding to preliminary engineering design and any subsequent project phases, SJRA is seeking public input on the proposed project alternatives detailed in the report. The full report, as well as a brief summary document, are located on SJRA’s Flood Management Division website.
Caution: The full study is dated 1/7/22. But the “brief summary” is dated 3/9/22. Make sure you at least read the executive study of the full report as well as the brief summary. There are important differences.
Overview/Purpose
SJRA says the purpose of the sediment trap study was to assess the feasibility of implementing a pilot project to trap and remove sediment from the West OR East Fork of the San Jacinto. The study only assessed locations where one or more Aggregate Production Operations (APOs) could partner with the the SJRA. They restricted the study this way to reduce costs; the SJRA does not have a source of funding to clean out sand traps and would rely on sand miners.
Initial Concerns
The decisions to:
Define the study objective as sediment reduction, not damage reduction and…
Only consider locations near sand mines…
…give me mixed emotions about this project.
Pros
On one hand, I look at this and say, “It’s a pilot project. Try it and see if there’s a benefit.” Sediment IS a problem and they believe they can remove up to 100% of the annual sediment load (from the West Fork).
Cons
On the other hand, the study authors, Freese & Nichols (F&N) claimed (in the San Jacinto River Basin Master Drainage Study) that of all the sediment coming into Lake Houston, two thirds comes from Spring and Cypress Creeks while only 13% comes from the West Fork upstream of US59.
Perhaps that’s because they’re using model inputs from a sediment gage at I-45 located 8.5 miles upstream from most of the large West Fork sand mines (page 34, paragraph 3 of full study).
The “Mouth Bar,” a giant sand bar that blocked the West Fork of the San Jacinto, backing the river up into Kingwood and Humble. Thousands of homes and businesses flooded behind this blockage. The above-water portion has since been removed, but most of the underwater portion remains.
In the entire 246-page F&N study and the three-page summary, the word “damage” occurs only once…in relation to erosion damage, NOT flood damage.
It appears that F&N did not even look at creating sand traps where they were most needed, in the headwaters of Lake Houston, because of cost and logistical considerations. Yet the Army Corps, City of Houston, and State of Texas are spending $200 million to dredge that area. One wonders whether SJRA should have looked harder for partners to clean out the traps.
Finally, if sediment traps only work financially near sand mines, the “solution” will not work on other tributaries that F&N alleges contribute 5X more sediment than the West Fork. They just don’t have the sand mines that the West Fork has.
Nature of Proposed Solution
Five years after Harvey, we have a conceptual design and a recommended location: rock-lined channels cut through one or two point bars at the West Fork Hallett mine.
The shot below shows the same area in real life. To put the magnitude of the proposed solution into perspective, the solution would cover a little more than an acre. But sand mines like Hallett cover 20 square miles on the banks of the West Fork between US59 and I-45.
2021 photo of sand bar outsde Hallett mine that would have a narrow channel cut through it to trap sand.
My Biggest Fears
My biggest fears with the proposed pilot study are that it:
Asks people to chose from a limited menu.
Could divert attention from better solutions that would reduce flood risk faster in the headwaters of Lake Houston.
Might make the public think the problem is solved.
Could open the door to river mining and further destabilize the riverine environment.
Is not a transferrable solution.
For a pilot study, that last point is troubling.
Also, F&N worries that removing too much sediment from the West Fork could create a “hungry-water” effect that increases erosion downstream. But they have no way of directly measuring how much sediment the West Fork transports. Or what percentage they would remove. That’s because they’re relying on a sediment gage upstream from the sand mines. This introduces an element of risk in the pilot study.
Recommendations Should Be Based on a Holistic Examination of Alternatives
Note lack of vegetation on this steep-sided, eroding bank of Hallett mine on West Fork in foreground.
Before moving forward with the pilot study, I suggest a more holistic examination of additional alternatives that might have a greater impact on reducing flood damage, not just sedimentation. Examples include, but are not limited to:
More on the sand trap proposal in coming days. In the meantime, please review the SJRA’s sediment trap proposal and forward your comments to the SJRA. I will also print thoughtful letters, both pro and con, from responsible parties. Send them to: https://reduceflooding.com/contact-us/.
Posted by Bob Rehak on March 27, 2022
1671 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/03/20210303-RJR_5381.jpg?fit=1200%2C800&ssl=18001200adminadmin2022-03-27 21:14:502022-03-28 01:10:10SJRA Seeks Public Input on Sediment Trap Proposal
Spring Creek Flood Control Dams are back in the news. The San Jacinto River Authority (SJRA) recently announced the first of three meetings related to a feasibility study. So save the date – April 7.
According to Matt Barrett of the SJRA, this feasibility study is a continuation of the Spring Creek Siting Study which came out of the San Jacinto Regional Watershed Master Drainage Plan project (SJMDP). The Harris County Flood Control District (HCFCD) and multiple partner agencies including SJRA developed the Master Drainage Plan.
Overview of Feasibility Study
The Spring Creek Siting Study from December 2020 explored multiple alternative locations that could provide flood-mitigation benefits to the Spring Creek watershed. Two of the more cost-effective were dams on Walnut and Birch Creeks.
The Spring Creek Flood Control Dams Feasibility Study will include:
A conceptual design for each dam
Benefits and costs for each dam and a combination of the two dams.
The goal: to determine the most feasible and economical alternative(s) for possible future design and construction.
The cost of the study is estimated at $1 million. The Texas Water Development Board (TWDB) Flood Infrastructure Fund (FIF) grant program will provide half. City of Humble, HCFCD, and five (5) Municipal Utility Districts will fund the other half. SJRA is performing in-kind services to reduce the local match amount to be funded by the Partners.
One Crucial Step of Many
This project is currently only in the feasibility phase. Construction of one or both dams, if feasible, would likely not occur for several years. Partners still need to identify a project sponsor and funding. They also need to perform final design, obtain environmental permits, and acquire land.
Details of Public Input Meeting
Public input and participation are critical components of this study, and SJRA wants to hear from you. A public meeting related to the study will be held on/at the following date and location:
Thursday, April 7, 2022
6:00 p.m. to 8:00 p.m.
Fields Store Community Center
26098 FM 362
Waller, Texas 77484
The meeting will be in an open-house format, allowing members of the public to come and go at their convenience at any time between 6:00 p.m. and 8:00 p.m. A five-minute, high-level, project-summary presentation will be given at 6:00 p.m., 6:30 p.m., 7:00 p.m., and 7:30 p.m.
Between these presentations, project team members will answer questions and collect input. If you can’t attend in person, you can view the summary presentation on SJRA’s Facebook page following the meeting. You may also submit questions via email and the project team will answer them.
Project Location
Below, see preliminary maps. These project areas could change based on the results of study efforts.
The proposed Spring Creek Flood Control Dams would lie in far northeastern Waller County, a few miles west of Magnolia in Montgomery County.
The next map shows parcels of land that partners would need to acquire to develop the project(s).
Preliminary map of Birch and Walnut Creeks flood control dams. Extent of inundation limits subject to change during study.One more public engagement meeting will be held this summer. The third will happen after partners release the draft report in February, next year.
Projected Benefits of Projects
As presently conceived, the Birch Creek dam could reduce water surface elevations by a half foot in a 100-year storm for almost 26 miles downstream. The larger Walnut Creek dam could produce a similar benefit for 41 miles downstream.
Each would cut the annual chance of exceedance (ACE) in half for the people in the affected areas. Thus, a hundred year storm would only have the impact of a 50-year storm.
Barrett currently estimates that the Birch Creek Dam could remove 815 structures from the 100-year floodplain and the Walnut Creek Dam could remove 1205. However, he also points out that those numbers will likely change as a result of updated modeling in the current study now underway.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/03/Preliminary-Locations-for-Spring-Creek-Flood-Control-Dams.jpg?fit=1200%2C796&ssl=17961200adminadmin2022-03-18 12:17:572022-03-18 13:53:06April 7 Meeting on Spring Creek Flood Control Dams
For an engineering study, it’s exceptionally easy to understand and the recommendations were prophetic. It almost reads like a primer for flood control.
Recommendations of specific projects aside, the principal recommendations are as valid today as they were then. Had only someone acted on them.
Make sure you at least read Chapter 5: Conclusions and Chapter 6: Examination and Recommendation of Basic Design Criteria for Watershed. Together, they total just five pages.
Purpose of Upper San Jacinto Study
The Upper San Jacinto study had four main goals:
Develop a comprehensive stormwater drainage plan
Recommend specific improvements
Evaluate/compare alternatives
Provide drainage authorities with information necessary to control flooding.
Problems of Rapid Development in Flat Areas
The study begins with a discussion of the problems of rapid development in flat areas. The Upper San Jacinto Watershed covers 1200 square miles. It includes all of Montgomery County and parts of Walker, Grimes, Waller, San Jacinto, and Liberty Counties. For the purposes of this study, the Harris/Montgomery County line formed the southernmost boundary.
Seven major streams comprise the watershed: the West Fork, Lake Creek, Spring Creek, East Fork, Caney Creek, Peach Creek, Luce Bayou and Tarkington Bayou.
The topography changes from rolling hills in the north and west to flat coastal plains in the south and east. The lack of slope in the southern and eastern regions seriously affects the ability of streams to drain stormwater.
The authors warned that as development would move northward, hydraulic “improvements” would alter natural stream patterns by increasing flow velocities and reducing ponding.
Without sufficient retention, development can accelerate runoff, leading to faster, higher peaks that contribute to flooding.
Even before urban development, they said, channels in the Upper San Jacinto Watershed did not have adequate capacity to transport runoff from large storms.
In 1985, at the time of the report, less than 5% of the land area in the watershed was developed. The Woodlands was relatively new and still building out. The report warned that because of development, increases in impervious cover “will require a more efficient drainage system to collect and transport runoff.”
The report lauded the type of development in The Woodlands, where, “discharges are no higher today than they were years ago in the undeveloped stages.” However, the report also cautioned that “…with most of the current development in the southern and eastern extremities of Montgomery County, watershed flooding problems may be greatly enhanced by urbanization.”
The chapter which discussed planning said, “Right of way and reservoir land acquisition should occur while the land is open and available.” Sadly, with the exception of Lake Conroe, which had already been built, none of that happened.
Benefit/Cost Ratios of Regional Detention in Undeveloped Areas
The last advice sounds so simple, one wonders why no one acted on it. However, as I read through the economic analyses of alternatives (reservoirs, channel improvements, etc.), the reason became blindingly clear.
So few people lived in undeveloped areas in the Upper San Jacinto Watershed in 1985 that the annual flood damages are minuscule. For instance, there were only 39 structures in four Lake Creek floodplain areas that the authors examined. Annual damages totaled only $9,600. That made the Benefit/Cost Ratios (BCRs) for the various mitigation alternatives that they developed come out to less than .001 in some cases and .09 at most. Benefits equal costs at 1.0. So FEMA usually demands BCRs exceed 1.
But compare the cost of a reservoir then and now. In 1985, the authors estimated the total cost of a Walnut Creek reservoir (a tributary to Spring Creek) to be only $41,000,000. Today, the cost would be $132 million – more than 3X. But it would take many more homes out of the floodplain. So the BCR today could be 1.04 making the project doable (see page 44)…although much more expensive and much to late to help those who flooded recently.
To get around this problem, the Harris County Flood Control District started its Frontier Program. The program buys up land for regional detention ponds (those that serve multiple developments), and then resells detention capacity back to developers for future use. Because regional detention is usually more efficient than developers building individual detention ponds on their own, it can actually lower developers’ costs while protecting the public and conserving money long term.
Most High-Level Recommendations Still Valid
Page 43 of the 1985 report makes six high-level recommendations (apart from specific projects) that are as valid today as they were then.
Create a central agency to control, monitor, remedy and finance flood control for the entire watershed.
Control development within the 100-year floodplain and prohibit it in the floodway with laws and regulations.
Establish minimum building slab elevations in flood-prone areas.
Limit fill in the floodplain.
Develop procedures to follow when allowing floodplain development, i.e., not obstructing 100-year floods.
Develop specific criteria, procedures and requirements for downstream impact analysis to compare Development A with Development B, and to analyze their combined effects.
Regular readers of this site have heard many of these recommendations before. The surprise, if there is one, is that we haven’t adopted them all already or that we haven’t adopted them consistently. Even where recommendations have been adopted, they are enforced inconsistently.
For future reference, the 1985 report can also be found on the reports page under the SJRA tab.
Posted by Bob Rehak on 9/19/2021
1482 Days since Hurricane Harvey and 731 since Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/09/Screen-Shot-2021-09-19-at-1.24.59-PM.png?fit=1084%2C1198&ssl=111981084adminadmin2021-09-19 15:07:542021-09-25 18:48:421985 Upper San Jacinto Flood Control Study Prophetic, But Largely Unheeded
Judge Mays dismissed the case WITH PREJUDICE FOR WANT OF JURISDICTION.
Meaning of “With Prejudice” and “Want of Jurisdiction”
“With prejudice” means that the plaintiff cannot refile charges in another court. Basically, the court is saying that it found the case meritless. One lawyer told me, “It’s like saying, ‘Don’t waste the court’s time anymore.'”
The massive floodgates on Lake Conroe (above) have 15X the release capacity of Lake Houston’s. The seasonal lake lowering program was conceived in part as a way to give Lake Houston more time to shed water in advance of major storms.
Re: Plea to the Jurisdiction, according to the website Houston Courts and Cases, “In Texas…A plea to the jurisdiction can challenge either the sufficiency of the plaintiff’s pleadings or the existence of jurisdictional facts.”
The ruling means that the SJRA’s Seasonal Lake Lowering Plan may remain in effect.
Purpose of Lake Lowering Plan
The Seasonal Lake-Lowering Plan was conceived shortly after Harvey as a way to provide an extra measure of flood protection for the Lake Houston Area while it implemented other flood-mitigation measures such as dredging and additional gates for the Lake Houston spillway. By creating extra storage capacity within Lake Conroe during the wettest months of the year, the SJRA hoped to reduce the risk associated with another massive release like the 79,000 cubic feet per second during Harvey. By itself, that was the ninth largest flood in West Fork history.
2800 Pages of Legal Briefs Come to a 102-Word End
The Lake Conroe Association pulled out the stops for this lawsuit. It filed approximately 2800 pages of legal briefs in four months, ran out of money, and started begging with residents to donate more so it could continue the fight. Today’s ruling will put an end to that.
Reality repeatedly contradicted the LCA’s factual claims. LCA claimed:
Home values around Lake Conroe would plummet because of the plan. They increased.
The school district would run out of money. It didn’t.
Nature would not be able to recharge the lake after a lowering. It did. Repeatedly.
Lake Conroe was not conceived as a flood-control lake. Flood control is a key element of SJRA’s charter.
The lowering would not help protect people in the Lake Houston Area. It did.
The City of Houston committed fraud … by calling for the release of its own water.
In contrast to (or maybe because of) the 2800 pages of legal briefs, today’s court order was mercifully brief – 102 words.
“On this 30th day of August, 2021, came on before the Court San Jacinto River Authority’s Plea to the Jurisdiction, and after considering same, all Answers, Responses, Replies, pleadings, stipulations, evidence, affidavits and attachments filed by the parties, all statutory and caselaw authorities, and all arguments relating thereto, the Court was of the opinion that the following Order should be entered; it is therefore ORDERED, ADJUDGED AND DECREED that San Jacinto River Authority’s Plea to the Jurisdiction be, and it is hereby, GRANTED AND SUSTAINED, and that the above Cause be, and it is hereby, DISMISSED WITH PREJUDICE FOR WANT OF JURISDICTION.”
Now a Meaningful Dialog Can Begin
I’m sure this must come as a bitter blow for some residents of Lake Conroe who supported the long court battle. But perhaps some good will come from the clarity that now exists.
Hopefully, this will open the door to reasonable people who wish to craft a long-term joint management plan for both Lake Conroe and Lake Houston. The people of this region are inextricably bound together by the need to balance water and flood control. Perhaps now we can start a meaningful dialog that addresses both.
Posted by Bob Rehak on 8/30/2021
1162 Days since Hurricane Harvey
00adminadmin2021-08-30 15:56:522021-08-30 15:59:58MoCo Judge Dismisses Lake Conroe Association Lawsuit Against SJRA With Prejudice
