Harvey: A 5-Year Flood-Mitigation Report Card

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.

State Representative Dan Huberty secured additional funding during the last legislature to continue maintenance dredging. That includes clearing drainage canal outfalls into the lake, such as the entrance to Rogers Gully. The dredging operation is now moving around the lake, according to the City’s District E office.

2) Adding Floodgates

Engineers keep looking for a cost-effective alternative. They first identified 11 options in a preliminary review. They then studied the most promising – spillway crest gates – in more detail. Now they’re looking at tainter gates in the earthen portion of the dam. In case the Benefit/Cost Ratio still doesn’t meet FEMA requirements for moving forward with construction, Houston Mayor Pro Tem Dave Martin is also exploring additional funding sources. But so far, no construction has started on additional gates. Martin hopes to reveal a recommendation in September.

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.

Coordination between Lake Conroe and Lake Houston has already improved. You can see it in the SJRA’s new dashboard. It shows releases requested by the City of Houston to lower Lake Conroe.

10) Sediment Reduction

Huge sediment buildups in the West and East Forks of the San Jacinto clearly contributed to flooding. The Army Corps stated that the West Fork was 90% blocked near River Grove Park. To reduce future dredging costs, SJRA also studied the use of sediment traps. SJRA may implement a pilot study soon on the West Fork near the Hallett mine.

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.

Federal Funding

It’s hard to get good grades on your flood mitigation report card without funding.

11-18) Appropriations

In March this year, Congressman Dan Crenshaw secured appropriations that should help advance projects in the San Jacinto Basin. They included:

• $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.

20) Woodridge Stormwater Detention Basin Expansion

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.

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.

25) Storm Sewer Inspections, Clean-Out, Repairs

The City has inspected storm sewers throughout Kingwood and cleaned those that had become clogged. It also repaired sinkholes and outfalls that had become damaged.

Lone Star Groundwater Conservation District

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