Tag Archive for: coastal water authority

Wastelands to Wetlands, Part III: Turning Ideas into Action

3/31/25 – In the first two parts of this “Wastelands to Wetlands” series, I presented a vision for restoration of the San Jacinto West Fork and listed all the various parties who have an interest in the effort and could help. But how do you coordinate them? Who would take responsibility/authority for ensuring restoration? And how would you measure their success? That is the focus of this post.

My purpose is to start a dialogue that gets people moving in the direction of a solution. I don’t claim to have all the answers. Nor do I believe that this is the only way to get to a solution.

Need for Leader to Guide Restoration

Right now, no group or leader exists for such an effort. But restoration will never happen unless someone takes the initiative (or has the responsibility) to turn ideas into action.

In business, I learned that if you put two people in charge of a project, no one is in charge. Right now, we have more than a dozen groups theoretically in charge of permitting various aspects of restoration. But none is in charge of oversight and coordination. That’s a problem.

Do We Use Existing Group or Start New One?

Several contenders for the job already exist. But do they have the knowledge, skills, funding and desire to take on the additional work?

The San Jacinto River Authority (SJRA) theoretically has the authority. And they have established a flood management division. But do they have the desire to take on the environmental restoration job? They architected a massive Master Drainage Plan for the entire river basin. But after more than four years, they have yet to implement one recommendation from it. SJRA seems focused on capturing water in Lake Conroe and selling it.

Further downstream, the Coastal Water Authority has the responsibility for managing Lake Houston. But no one has given them responsibility for fixing upstream issues between the two lakes that pollute their water.

Unless one of these two groups accepts restoration as a mission and dedicates the resources to achieving it, we need to create another authority responsible for the area between Lake Conroe and Lake Houston – a West Fork Restoration Authority.

Mission Defined

Their mission: turn wastelands into wetlands. How? 1) Restore abandoned mines using a combination of grants and matching funds dedicated to the effort by the state legislature. 2) Monitor active mines to ensure they comply with their abandonment plans when the time comes. 3) Coordinate the efforts of all affected parties to ensure they are additive and contribute to the long-range plan over time.

Creating such an authority would require action by the state legislature in 2027. It’s too late for this session.

Board Structure

A board appointed by the governor and affected parties, such as the City of Houston, Montgomery County, the mining industry, and residents, could manage the West Fork Restoration Authority.

Suggested Success Metrics

How would they measure success? Here’s a list of major needs, metrics, and milestones.

  • A) Completion of business plan
  • B) Acquisition of staff
  • C) Completion of engineering study
  • D) Design of solution and component parts
  • E) Costs estimates
  • F) Publication of long-term plan with stages/tasks outlined
  • G) Successful grant applications, funds raised
  • H) Permits obtained
  • I) Acres revegetated
  • J) Linear feet of trails installed
  • K) Reduction of erosion
  • L) Water-quality improvements
  • M) Publication of quarterly and annual progress reports
  • N) Creation of case study that communicates knowledge gained to guide similar efforts elsewhere

Time Limited

The State’s Sunset Commission would review the Restoration Authority at regular intervals (currently 12 years) and dissolve it after completion of its job or for lack of progress.

Need

Do we need such an Authority? In my opinion, YES! The economic future of the region depends on eliminating the blight that contributes to flooding. The West Fork has:

  • Approximately 20 square miles of sand mines, many abandoned, between Lake Houston and I-45
  • Become completely blocked in some areas
  • Broken through the dikes of at least five sand mines.

The American Rivers organization named the West Fork one of the most endangered rivers in America.

And we still have not completed a $200 million dredging program that began in 2018.

Back in 2019, I posted 72 pictures that showed the extent of sand mining on the West Fork. Sadly, not much has changed since then. In fact, things have gotten worse.

West Fork Sand-Mining Problems
Hallett Mine on West Fork. Picture taken March 19, 2025. Pit in foreground has been captured by river, cutting off normal channel to right.

We need the area’s elected leaders to work together to restore the West Fork as mines like the one above play out and the miners move on to other areas.

We need their help in turning Wastelands into Wetlands. Otherwise, the next generation will be stuck with the situation below.

New Sand Mining BMPs needed to offset sediment pollution.
Confluence of Spring Creek (left) and West Fork (right) with its 20 square miles of sand mines. Photo taken in January 2025

Posted by Bob Rehak on 3/31/25

2771 Days since Hurricane Harvey

Flood-Control, Water-Supply Dam Differences Help Explain Delay on Lake Houston Gates

9/29/24 – When talking about using the Lake Houston Dam to help control flooding, one often hears experts say, “That’s not a flood-control dam. That’s a water-supply dam.” So, what’s the difference? And why does it make a difference?

The purpose of the dam influences its design, operation and management. An insider familiar with the effort to add more gates to the Lake Houston Dam said last week that engineers at both Houston Public Works and the Coastal Water Authority have resisted trying to modify a water-supply dam for flood control.

This is not the only reason this project has taken so long to get off the ground. But it helps explain why new, higher capacity Lake Houston gates are just now going into final design – 2588 days after the storm that made the need abundantly clear.

To put that in perspective, 2588 days is almost twice the number of days that it took to win World War II.

Conflicting Purposes, Designs

The primary purpose of a flood-control dam is to reduce flood risk by controlling the flow of water downstream during heavy rains. They accomplish this by temporarily holding back the flow of water. They then release it later in a controlled fashion to smooth out peaks and reduce flood damage.

To mitigate flooding, flood-control dams:

  • Often have lower water levels under normal conditions to accommodate sudden influxes of water.
  • Have large spillways and gates to rapidly release water when needed.
  • Are designed with a large storage capacity relative to the expected flood volumes.
  • Are sometimes kept partially empty to ensure sufficient space for incoming floodwaters.
  • Have more robust construction to withstand sudden large inflows and outflows.

On the other hand, the primary purpose of water-supply dams is to store water for human consumption (drinking, bathing, irrigation, industry, etc.).

To ensure consistent supply, a water-supply dam:

  • Prioritizes a consistent water level to ensure a reliable supply of water throughout the year, even during droughts.
  • Is usually kept at higher levels.
  • Stores water over longer periods.
  • Is managed to ensure sufficient supply throughout the year, with a focus on maximizing storage before dry seasons.

In summary, a flood-control dam is designed and managed to mitigate floods by managing excess water. However, a water-supply dam aims to store water for human use.

In practice, these extremes aren’t quite as mutually exclusive as the terms might imply.

Seasonal Management and Its Alternatives

Seasonal management strategies can help bridge the gap between the two. For instance, operators often manage both types of dams seasonally so they have more storage space during rainy seasons when flood risk spikes.

The SJRA adopted a seasonal lake-lowering strategy for several years after Harvey. But because of political pushback from Lake Conroe residents, the strategy was abandoned after several years.

“Stop the Drop” protesters pack an SJRA board meeting in December 2019.

SJRA now uses another hybrid strategy called “active storm management.” “Active Storm Management” seeks to manage lake levels by releasing water based on real-time weather forecasts to manage reservoir levels more effectively.

Other operators use a similar strategy known as FIRO (Forecast-Informed Reservoir Operations). Advanced forecasting models predict inflows and adjust dam releases preemptively.

Lake Houston, Lake Conroe Both Water-Supply Dams

Both Lake Conroe and Lake Houston are water-supply dams. But Lake Houston, built in the early 1950s, has a 3160-foot, fixed-height spillway with four small gates capable of releasing only 10,000 cubic feet per second (CFS) combined. Clearly, engineers prioritized consistent water level over flood mitigation when designing this dam. The small gates make it difficult and time consuming to release water before it reaches the level of the spillway.

According to the Houston Public Works Drinking Water Operations Group, Lake Houston supplies water to 2.2 million people.

Lake Conroe, built in 1973, has five large gates capable of releasing 150,000 CFS. It was designed as an alternate water supply for the City of Houston. The City financed its construction and owns two thirds of the water in the lake.

Lake Conroe has nothing comparable to the fixed-height spillway on Lake Houston.

3160-foot concrete and steel spillway on Lake Houston

Compared to spillway above, gates on Lake Houston can release only a small amount. But the spillway can release more than Lake Conroe. See below. It just can’t release that much before a storm.
Lake Houston Dam during Harvey. The wall of water flowing out of the lake was 11 feet higher than the spillway.

During the peak of Harvey, an estimated 425,000 CFS went over the Lake Houston Spillway – 5 times the average flow of Niagara Falls.

In contrast, Lake Conroe released about 80,000 CFS from its gates during Harvey. So why the push to add more gates to Lake Houston?

Gates Key to Hybrid Strategy

Simple. Bigger gates are key to both water conservation and Active Storm Management. Right now, Lake Houston’s gates are so small that lowering the lake significantly can take days. During that time, storms can veer away.

That long lead time creates uncertainty that jeopardizes what Houston Public Works and the Coastal Water Authority see as their primary mission – providing water for 2.2 million people.

We just can’t create extra storage capacity in Lake Houston fast enough with the existing gates.

Why is Design Taking So Long?

But with more, larger gates, Lake Houston could release enough water in hours to create extra storage capacity. And operators would have confidence that water would not be wasted. So why are the gates taking so long?

Design of more gates for Lake Houston has just now started. Using Harvey as a starting point, we are now almost at twice the amount of time that it took to win World War II.

It’s hard to believe that if everyone agreed with the need for more flood gates, it would have taken this long to start design.

In that regard, I have heard of pushback from both Houston Public Works and Coastal Water Authority. The pushback had to do with the mission of the organizations: to supply water. They just didn’t want to risk wasting it in case we encountered drought.

But our two backup water sources (Lake Conroe and Lake Livingston) combined have 15 times the volume of Lake Houston. So the City probably won’t run short anytime soon.

Flood Mitigation Not In CWA Mission

The Coastal Water Authority, which is the City’s contract operator for Lake Houston, does not even mention “flooding” on its website. That’s right. CWA doesn’t mention the word in its mission statement, guiding principles, strategies, or tactics. They do, however, mention “pumps” 15 times on their Strategic-Plan page. That should give you some idea of their priorities: water supply.

Hopefully, Mayor John Whitmire’s recent appointment of former State Representative Dan Huberty to the Coastal Water Authority Board will help the CWA see Lake Houston from more than one perspective. Huberty has advocated for the gates since Harvey.

Posted by Bob Rehak on 9/29/24

2588 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.

Harvey’s Seventh Anniversary Update on Lake Houston Floodgates Project

8/28/24 – In its July 10 board meeting, the Coastal Water Authority (CWA) unanimously approved a motion to move forward with final design for 11 new Lake Houston floodgates. Houston will now consider the same motion at its September 11th City Council Meeting. If approved, final engineering design of the gates will commence.

Separately, Houston Mayor John Whitmire appointed former State Representative Dan Huberty to the CWA board. Huberty, an early proponent of the gates project, may be able to help accelerate it moving forward.

The Most Talked About Flood-Mitigation Project

Since Hurricane Harvey seven years ago, I’ve authored 278 posts discussing additional Lake Houston floodgates. From the public’s standpoint, beyond a doubt, the gates are the most eagerly anticipated flood-mitigation measure considered after Harvey.

The most recent post appeared on 5/25 of this year after meeting with members of the Coastal Water Authority, Houston City Council and Houston Public Works at the dam. Not much has changed since then with the exception of some legal formalities.

The Coastal Water Authority Board met on July 10 to vote on an amendment to an Interlocal Agreement (ILA). FEMA and the Texas Division of Emergency Management previously approved the ILA amendment in April. It covers additional engineering services, the cost of final design, and changes from the initial scope of work.

The CWA board approved the ILA amendment unanimously. Final engineering of the new Lake Houston floodgates can now move forward with Black & Veatch as soon as the City approves it.

Minutes of the CWA meeting indicate that, before voting, members discussed potential downstream impacts. The minutes also noted that no significant impacts were found after extensive hydraulic modeling.

Next Up: City Council Vote on 9/11

The amended interlocal agreement will now go before Houston City Council on September 11th for consideration. If approved, final design of the gates could begin soon thereafter.

Need for Lake Houston Floodgates

The Lake Houston Floodgates Project will add 11 new gates to the dam in the earthen embankment to the east of the concrete spillway.

Proposed location for new tainter gates
Approximate location for 11 new Lake Houston floodgates.

The new floodgates will increase the current discharge capacity by an additional 80,000 cubic feet per second (CFS). That roughly equals the discharge rate from Lake Conroe during Hurricane Havey – 79,000 CFS.

Currently, Lake Houston floodgates can only release 10,000 CFS. Increasing the discharge rate would enable the City and CWA to:

  • Coordinate pre-releases between Lakes Conroe and Houston before major storms without swamping the Lake Houston Area.
  • Discharge as much water from Lake Houston in 2-3 hours as they now do in a day.
  • Release water when approaching storms are much closer, reducing the risk of wasting water if storms veer away.
  • Create extra storage capacity in both lakes, reducing flood risk for residents around them.
  • Reduce flood peaks, helping protect residents between the lakes and downstream from the Lake Houston Dam.

Key to Active Storm Management

All these benefits are especially important because the San Jacinto River Authority (SJRA) has abandoned its seasonal lake-lowering strategy for Lake Conroe. The SJRA has gone to an as-needed lake-lowering strategy called “Active Storm Management” instead. Active storm management requires much more speed and agility than simply having extra storage capacity in the lakes ready and waiting when storm seasons begin.

Lake Houston Area residents got a taste of “Active Storm Management” without the extra gates in May this year. SJRA got surprised by a spring storm and started releasing water at 70,000 CFS. Hundreds of homes flooded downstream in Harris and Montgomery Counties. Thousands more nearly flooded.

The May floods highlighted the risks involved with ad hoc lowering of Lake Conroe. They also underscored the need for more Lake Houston floodgates to handle the extra water that SJRA may send downstream.

2556 days have now elapsed since the storm that motivated the Lake Houston floodgates project – without moving one shovel of dirt. That’s almost twice the time that it took to fight and win World War II – 1349 days.

I’m going to go way out on a limb here and say that there may be some room for improvement in the business processes surrounding flood mitigation.

Whitmire Appoints Huberty to CWA Board

On the good-news front, Mayor John Whitmire has appointed former State Representative Dan Huberty, a Lake Houston Area resident, to the CWA board. Huberty fought years for this project and helped land much of the early funding. He knows the people and already knows the project. He should be able to step in and start making an immediate impact.

Huberty has already had meetings with the CWA staff. He told me, “This will be my highest priority moving forward to meet the needs of Lake Houston Area constituents.”

Posted by Bob Rehak on 8/28/2024

2556 Days since Hurricane Harvey

West and East Forks of San Jacinto Flooding Again

May 19, 2024 – For the second time this month, the West and East Forks of the San Jacinto River are flooding. The East Fork crested last night about 1.5 feet below the prediction. However, the West Fork is still rising at US59. Parts of River Grove Park and the turnaround under US59 are already flooded. And the National Weather Service predicts floodwaters will go even higher.

Meanwhile, the West Fork continues to run through an old Hallett sand pit that was sold in January.

Here’s what you can expect if you live near the rivers.

East Fork Crest Moving Toward Lake Houston

Low-lying areas along the East Fork began flooding yesterday at FM1485. Earlier, the East Fork flooded near Cleveland and Plum Grove. As the crest moves downriver, it is affecting communities differently. Exactly how depends on many factors, such as the conveyance of the river at different points, sediment accumulations, proximity of homes to the river and more.

Yesterday, water was coming across part of FM1485 where it crosses the East Fork and parallels SH99. Today, the entire east bound section of FM1485 was blocked by floodwaters.

East Fork San Jacinto at approximately 4:30 PM on 5.16.24
East Fork San Jacinto at approximately 4:30 PM on 5.16.24

As of 6 PM, May 19, floodwaters are declining in this reach of the river. The crest has moved downstream toward Lake Houston.

Harris County’s Flood Warning System shows the river crested last night but was still well above flood stage as of noon today.

Farther upstream, at FM2090, the river has already returned to its banks.

All this is the result of another 3-5″ of rain falling earlier in the week upstream in the watershed on grounds that were already saturated from torrential rains and flooding earlier this month.

NWS Issues Flood Warning for West Fork until Tuesday Morning

While the East Fork is falling at this hour, the West Fork is still rising. At 1:34 PM Sunday, the National Weather Service issued a flood warning for the West Fork near Humble affecting Harris and Montgomery Counties.

Communities affected include: Porter, Sendera Ranch Road, Conroe, Kingwood, Humble, Sheldon.

Only minor flooding is forecast.

National Weather Service Flood Warning

NWS will issue its next statement Monday morning at 7:45 AM CDT.

The FLOOD WARNING WILL REMAIN IN EFFECT UNTIL LATE TUESDAY MORNING.

IMPACTS: At 49.3 feet, minor lowland flooding begins in the vicinity of the gauge at US59. The north side turnaround at US 59 begins to flood. Low points in surrounding areas also begin to flood.

At 12:45 PM CDT Sunday, the river had risen to 49.2 feet.

 Bankfull stage is 45.3 feet.

The river will crest at 49.7 feet just after midnight tonight. It will then fall below flood stage late tomorrow evening.

Flood stage is 49.3 feet.

This afternoon, the turnaround under US59 was just beginning to flood. The parking lots and part of the roadway were already underwater.

Far side of sandbar in middle is normally the river bank.

At 5 PM, the soccer fields, picnic area and boat launch at River Grove Park were also partially underwater. And water was rising quickly.

Picnic area and boat docks at River Grove underwater and going deeper tonight.
Soccer fields, also at around 5PM
River still rising. Minor flooding expected through Tuesday.
Sand Mine Area Upstream

Farther upstream, the West Fork was still ripping a hole through an abandoned Hallett sand pit that the company sold to a real estate developer in January.

River is now flowing through the abandoned pit (right) instead of following the normal arc of the river (left) around the pit. Note trail of foam. It moved at around 5 mph.

This breach appears to have widened significantly in recent days. If it remains open and this pit becomes the new course of the river, it’s possible that the entire pit could become public property, just like the river is now.

On the other side of the river, Hallett filled in the trench that was releasing sludge from its settling pond last Friday afternoon.

Trench on perimeter of Hallett Mine that was releasing sludge into river on Friday afternoon has been filled in.

Lake Report

As of 7 PM, the SJRA is releasing 5,325 Cubic Feet per Second (CFS) from Lake Conroe. The lake is almost back to its normal level – within .67 feet of 201. And no rain is in sight. That’s good news. Releases should continue to go down.

Screen capture from SJRA website at 7:15PM.

Throughout this event, SJRA has balanced inflows and outflows to the degree that it can. The rate they show above is about half of what they released earlier in the weekend.

Lake Houston, however, is getting more, not less water. It is still about two feet above normal and discharging water via its gates and spillway. Total discharge is 34,015 CFS. Of that, the gates can release only 10,000 CFS. The other 24,000 CFS goes over the spillway.

Screen capture from Coastal Water Authority as of 7:15 PM.

Comparing the two numbers on the right, shows us that the flood risk is shifting to the Lake Houston Area now.

Of the 11 watersheds that send water into Lake Houston, SJRA controls only Lake Conroe. The East Fork has no flood control. But that’s a story for another time.

Posted by Bob Rehak on 5/19/24 at 8PM

2455 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.

City of Houston Re-evaluating Benefit-Cost Ratio on Lake Houston Gates Project Alternatives

According to minutes of the Coastal Water Authority (CWA) February 9 board meeting posted in March, work on the project to add more gates to Lake Houston was paused in January while the City of Houston updated the project’s benefit-cost ratio.

gates for Lake Houston and Conroe
Lake Houston and Lake Conroe gates side by side. Lake Conroe’s gates (right) can release water 15 times faster.

CWA Board Minutes Give High-Level Overview of Concerns, Status

Screen capture from CWA Feb. 9, 2022, minutes approved and posted in March.

Earlier, in December, the board learned that the project team was trying to get the benefit/cost ratio above 1.0, so benefits exceed costs.

Screen capture from CWA January 12, 2022, board minutes.

At that time, the CWA hoped to receive the updated BCR later in January. But it still hadn’t happened by the February board meeting.

Martin Says “September-ish” for BCR Report

City of Houston Mayor Pro Tem Dave Martin said he hopes to have the BRC report in a “September-ish” time frame. I asked him whether the Community Impact report was accurate when it said the project had been scaled back to 500 feet of crest gates as opposed to the original 1500 feet. He said “no,” and that the engineers were looking at multiple options. He also said “1.0 is incorrect as well,” but did not elaborate.

That leaves a lot of questions regarding this project.

History of Project

After Harvey, the Lake Houston Area Task Force identified adding additional gates to Lake Houston as one of three primary strategies to reduce flood risk in the Lake Houston Area. The idea: to equalize the discharge rates of the flood gates on Lake Houston and Lake Conroe. Conroe’s is 15X greater. That makes it difficult lower both lakes quickly in advance of approaching storms.

As a temporary strategy, the City and SJRA agreed on a temporary, seasonal lake lowering strategy to create more capacity in Lake Conroe until more gates could be added to Lake Houston. But the strategy met with significant pushback from Lake Conroe residents and lawmakers. The Lake Conroe Association even took the SJRA to court to stop it.

At various times, City representatives have discussed 10 and 6 additional tainter gates, plus 1500-, 1200-, and 1000-feet of crest gates. Engineers and City officials have repeatedly emphasized the need to balance costs, downstream impacts, and flood risk reduction.

Back in October 2020, the engineers calculated that the upstream influence of the dam ended at approximately Lake Houston Parkway. But they never explained why. It would seem that if the influence extended upstream to US59 when the lake is at its normal level, that the influence should extend at least that far in a flood. However…

BCR Not Based on Harvey Damage

Much of the damage to the Humble/Kingwood Area during Harvey happened upstream of the West Lake Houston Parkway Bridge. It included:

  • $60 Million to Kingwood College
  • $70 million to Kingwood High School
  • $50 million to Kingwood County Club
  • 283 homes in Barrington
  • 218 homes in Kingwood Lakes
  • 97 apartments in Kingwood Lakes
  • 110 homes in Kings Forest
  • 100% of businesses in Kingwood Town Center
  • 225 homes in Kingwood Greens
  • 30 homes in Deer Cove
  • 3 Homes in Deer Ridge Estates
  • 32 homes in Trailwood Village
  • An unknown number of homes in Forest Cove
  • 78 townhomes in Forest Cove
  • All of the Big Box stores along 59
  • Homes and business north of Deerbrook mall
  • 40% of all businesses in the Lake Houston Chamber
  • Humble ISD admin building
  • Destruction of US59 southbound lanes
  • Union Pacific Railroad Bridge

However, Black & Veatch does not base its benefit-cost ratio calculations on another Harvey. They’re basing it on 25- and 100-year storms. Almost all homes, businesses and infrastructure near the lake are already above those levels – at least based on pre-Atlas 14 standards. That may explain the difficulty and delays with benefit/cost ratio calculations and the multitude of scenarios examined.

Time, Uncertainty: More Factors to Consider in Cost and Risk Reduction

Each flood-risk reduction alternative would reduce lake levels by a different amount during a 100-year storm and therefore require its own BCR.

Other factors to consider: How much time do dam operators really need to lower Lake Houston? And how much uncertainty are they willing to live with?

Given the desire to preserve water, these are crucial considerations. If forecasters can reliably predict a need to lower the lake two days before a storm instead of one, operators may only need half the number of new gates. That could get the cost down to the point where the benefit-cost ratio needs to be.

But don’t forget another element of uncertainty: Atlas 14. FEMA has not yet approved the new flood maps based on the higher rainfall totals. Those could put more people in or closer to the floodplains. Below is the timetable for flood map updates currently posted on the MAAPnext website.

Timetable for flood map updates from MAAPnext.

Posted by Bob Rehak on 4/4/22 and updated on 4/5/22 with MAAPnext timetable

1679 Days since Hurricane Harvey

May 2021 Gate Project Update for Lake Houston Dam

In its March 10th board meeting, the Coastal Water Authority (CWA) accepted the recommendation of a preliminary engineering report to add one thousand feet of crest gates to the uncontrolled spillway portion the Lake Houston Dam. The additional release capacity would let operators shed water faster before, during or after major storms to reduce the risk of flooding.

At the March meeting, directors also approved $4.4 million to begin Phase II of the project. Phase II calls for Black & Veatch to proceed to final engineering of the gates and a coffer dam to protect the work area during construction.

Read the minutes of the March board meeting here. The discussion of the gates starts on page 4 under Item B.

This morning, at its May board meeting, directors received an update on the progress of Phase II work to date and plans for the remainder of the project.

Start of Phase II Engineering Approved in March

In the March meeting, CWA approved funds to begin Phase 2 of the engineering which includes the final design of the selected alternative by Black & Veatch. The selected alternative was “crest gates” constructed on the uncontrolled spillway portion of the dam on its west side. (See below.)

Looking NE at the Spillway of the Lake Houston Dam is in foreground. One thousand feet (about a third) of this spillway will be replaced with crest gates. Gates will be placed at the end closest to the camera position in the image above.

Dam operators can raise or lower crest gates from a bottom hinge, much like the lid on a piano. When in the up position, gates hold water back. When lowered, they release water.

During Harvey, the peak flow over the spillway was five times the average flow over Niagra Falls. A wall of water 11 feet tall cascaded over the spillway above. Enough to fill NRG stadium in 3.5 minutes.

Scope of Phase II Design Work

Also in March, CWA and Black & Veatch completed negotiation of the scope and fee for the final design. The key deliverables during Phase II will include:

  • Plans to modify the spillway to support the 1,000 linear feet of crest gates (in five 200-foot long sections)
  • Design of the cofferdam system to protect the work areas during construction
  • Preparation of a new gate operations plan for CWA Lake Houston Dam operators.

Director Douglas Walker moved to authorize the Executive Director to issue a contract amendment with Black & Veatch Inc. in the amount of $4,465,727.00 for “Phase 2 – Final Design of the Lake Houston Dam Spillway Improvement Project.” Director Giti Zarinkelk seconded the motion. The Motion carried unanimously.

May Update

In the May board meeting this morning, directors received an update on Phase II work to date and plans.

In April, the design team held a number of workshops and coordination meetings.

Black & Veatch also completed three weeks of field surveying of the existing spillway; that’s why CWA temporarily lowered Lake Houston during that period.

In other news, for next steps CWA will:

  • Submit the permit application to the US Army Corps of Engineers by the end of May.
  • Support City of Houston in a public outreach meeting scheduled for June 17. The public outreach meeting will coincide with the public comment period for the permit application. CWA expects permitting to take nine months, i.e., through March of 2022.
  • Complete final design by the end of September 2022.
Screen capture from portion of CWA Board meeting today shows status of Phase II Design work on the dam.

Next Steps

Does all this mean construction is assured? No. The Army Corps could reject the permit or FEMA could find some fault with the plans. But at least it shows progress. If all plans and permits are approved, construction dollars have already been committed by FEMA. Originally, construction was supposed to have been completed within three years from April 8, 2020. That now looks unlikely unless the City can obtain a deadline extension from FEMA..

Posted by Bob Rehak on 5/12/2021

1352 Days after Hurricane Harvey

October 2020 Gate Update

On Friday, October 16, 2020, stakeholders in the Lake Houston Spillway Improvement Project met at the dam to review gate alternatives and progress on the project. The main item of interest: a review of options still under consideration to increase the outflow during major storms, such as Harvey.

History of Project

Shortly after Harvey, representatives from the Lake Houston Area identified “increasing outflow” as one of the main strategies to reduce flooding. Harris County Flood Control District even conducted a pilot study. Flood Control included $20 million for the project in the 2018 bond fund (CI-028). With matching funds identified, grants were then written.

FEMA approved the project. And in April of this year, the clock started ticking on the first of two phases.

Phase One Includes…

Phase One includes preliminary engineering and environmental permitting. It should take 18 months and is on schedule at this point. A key deliverable for phase one is verification of the benefit/cost ratio. But, of course, to determine that, you need to know the cost.

Alternatives Still Under Consideration

FEMA allotted 18 months for Phase 1. We’re six months into that. Work to date has focused on determining the optimal alternative. Five remain:

  1. Expanding the existing spillway by adding new tainter gates
  2. Adding a new gated spillway within the east embankment
  3. Creating a new uncontrolled spillway within the east embankment
  4. Building crest gates within the east embankment
  5. Developing crest gates within the existing spillway

Tainter gates lift up from a radial arm. The tainter gates on Lake Conroe have 15X more release capacity than the lift gates on Lake Houston.

Crest gates flop down from a bottom hinge.

Above: the current conditions at the Lake Houston Dam. Looking slightly upstream. East is on the right.

The east embankment is a solid earthen area 2800 feet long east of the spillway and existing gates. Water cannot get over it in a storm. By adding various structures in this area, engineers could widen the current spillway capacity, allowing release of more stormwater.

One main benefit: additional gates would reduce uncertainty associated with pre-releases. Operators could wait longer until they were certain an approaching storm would not veer away at the last minute. That would avoid wasting water.

Reverse angle. Note the difference in height between the east embankment (left) and the spillway (right). Looking downstream toward Galveston Bay.
Looking west toward Beltway 8. This shows the major segments of the dam.

Benefit/Cost Ratio Must Be > 1.0

The lake-level reduction benefits of these gate alternatives during major floods range up to roughly 8x. The costs also vary by roughly 4x. Those are order-of-magnitude, back-of-the-envelope estimates and far from final. Much hard work remains to develop tighter costs and tighter estimates of flood-level reductions. The latter will determine flood-prevention savings in a storm. And the benefits divided by the costs will determine the benefit/cost ratio.

In FEMA’s eyes, the benefit/cost ratio must exceed 1.0 to justify the project. Said another way, it must produce more benefits than it costs.

FEMA allotted 18 months for phase 1. We’re six months into that phase with a year left. Project partners expect results of the alternatives analysis before the end of the year.

Benefit/Cost Calculation

Given the ballpark costs of some of these gate alternatives, we will need very tight estimates of the benefits.

Potential Benefits include:
  • Upstream flood risk reduction
  • Reduced maintenance (debris management) for CWA
  • Improved Water Quality (post storm)
Potential Impacts include:
  • Increased scour and erosion potential to wetlands downstream
  • Increased water surface elevations to structures downstream
Calculating Benefits

Benefit Cost Ratio = (Net Present Value of Benefits)/(Project Costs)

Project Costs = (Capital costs) + (Net Present Value of Operations and Maintenance Costs)

Major Tasks Remaining in Phase 1

Barring surprises, the preliminary engineering report is due in February 2021 and environmental permitting should be complete by the Fall of 2021. Other tasks that must be completed by then include:

  • Hydrologic modeling of flows into and out of Lake Houston using the latest Atlas 14 data
  • Hydraulic modeling of Lake Houston, its Dam, and the San Jacinto River downstream of the dam to Galveston Bay
  • Calibration of models to historic storms
  • Examination of upstream benefits to residents/businesses removed from flood impacts
  • Examination of downstream impacts associated with additional flow release scenarios

It’s important to understand that not everyone who flooded in the Lake Houston Area did so because of the lake level. Some on the periphery of the flood flooded because water backed up in streams leading to the lake. If you got two feet of water in your living room, it doesn’t automatically mean a lake level reduction of two feet would eliminate your flooding by itself.

Congressman Dan Crenshaw (left) reviews the project with team members at the Lake Houston Dam and listens to their needs.

Phase 2 Still Not Certain

Assuming all goes well in the planning, accounting, and conceptual validation, FEMA will make a go/no go decision on construction at the end of next year or the beginning of the following year. Construction should take another 18 months.

Credits

Funding for this project comes from FEMA, Texas Division of Emergency Management, City of Houston and Harris County Flood Control. Other stakeholders include the Coastal Water Authority, Harris County, Fort Bend County, Baytown, Deer Park, and other communities adjacent to Lake Houston.

Posted by Bob Rehak on 10/17/2020

1145 Days since Hurricane Harvey and 394 since Imelda

Beta Downgraded to Tropical Depression

At 10 a.m. CDT, the National Hurricane Center (NHC) downgraded Tropical Storm Beta to a tropical depression. The NHC also cancelled the tropical storm and storm surge warnings that were in effect. However, flash flood warnings remain in effect for large parts of the seven-county Houston region, especially the southern part. A flash flood watch remains in effect for the entire region.

RadarScope split image. Left half shows track of active storms as of 9:06AM CDT. Right half shows total rainfall accumulation for Beta. Note band of extreme rainfall near Sugar Land and sharp drop-off near Kingwood.

Flash Flood Warnings and Watches

A flash flood warning means that flooding is in progress. A Flash Flood Watch means that conditions may develop that lead to Flash Flooding.

Source: National Weather Service. Updated at 10:29 a.m. 9/22/2020. Reddish area = Flash flood warning. Green = Flash flood watch.

Lake Conroe/Lake Houston Within Banks

Neither Lake Conroe, nor Lake Houston have yet been adversely affected by Beta.

The level of Lake Conroe stands at 199.63 feet. Normal conservation pool equals 201.

According to the Coastal Water Authority, Lake Houston is at:

Lake Level41.41 ft.
Normal Pool42.4 ft.
Source: Coastal Water Authority

USGS shows that even though the lake has received about 1.75 inches of rainfall to date…

…the lake level has been dropping, no doubt due to a preemptive release.

Posted by Bob Rehak at 10:50 on 9/22/2020 based on NHC, NWS, and RadarScope data

1120 Days since Hurricane Harvey and 369 since Imelda

Long-Term Lake Houston Dredging Plan in Development; West Fork Mouth-Bar 60 Percent Completed

In January, the City hired DRC Emergency Services, LLC (DRC) to begin mechanical dredging of the San Jacinto West Fork Mouth Bar. I’ve provided periodic updates on that. According to Houston Mayor Pro Tem Dave Martin, DRC has now officially completed 60% of that project.

In the meantime, other related dredging projects, including East Fork dredging and long-term Lake Houston maintenance dredging are reportedly taking shape. Here’s how pieces of the puzzle fit together. But one piece is still missing – long-term funding to pay for the maintenance dredging.

Two-Phase Program

DRC’s scope of work has two distinct phases:

  1. Phase One will remove accumulated materials near and at the mouth bar on the West Fork of the San Jacinto River.
  2. Phase Two will remove accumulated materials in the East Fork of the San Jacinto River AND other locations in Lake Houston.
West Fork Mouth Bar as of late June 2020.

During Phase One, 400,000 cubic yards of material will be removed over twelve months. To date, DRC has removed approximately 240,080 cubic yards of material. (See photo above.) That’s 60% in approximately 60% of the allotted time, so that part of the project is on schedule.

East Fork Mouth Bar as of May 2020. This areas went from 18 to 3 feet deep during Imelda, according to boater Josh Alberson. The above-water portion of this sand bar has grown three quarters of a mile since Harvey.

Phase Two of the project will consist of:

  • Hydrographic surveys of the West Fork of the San Jacinto River, the East Fork of the San Jacinto River, and Lake Houston to determine dredge material volumes
  • City of Houston advertising and awarding a dredging contract to the lowest responsive bidder

Phase Two will run simultaneously with Phase One to expedite dredging. 

Dave Martin, Houston Mayor Pro Tem

Mayor Pro Tem Martin did not provide an update on where Phase Two currently stands. But residents have reported seeing survey boats on Lake Houston, and the East and West Forks of the San Jacinto.

Mouth bar forming at Rogers Gully on Lake Houston. Example of kind of projects being considered for Phase 2. Photo late June, 2020.

Long-Term Dredging Plan in Development

Additionally, during Phase Two, City of Houston and its partners will develop a long-term dredging plan for Lake Houston. City of Houston or the Coastal Water Authority will execute the plan.

The intention: to fund dredging operations in perpetuity.

This phased approach will obligate the full grant funding before the 87th legislative session in 2021. This grant funding was made possible thanks to State Representative Dan Huberty (District 127) through the passage of Senate Bill 500.

Mayor Pro Tem Martin credits Huberty for his dedication to the long-term maintenance dredging activities on Lake Houston. “Representative Huberty has been a champion for his residents and a great ally in seeing these additional dredging efforts come to fruition,” said Martin.

$40 Million Project

The total project is valued at $40 million (except for the perpetuity part). Funding for the immediate dredging projects comes through a combination of:

  • City of Houston Harvey Disaster dollars provided by Governor Greg Abbott
  • Grant dollars from the Texas Water Development Board (TWDB)
  • Harris County Flood Control District (HCFCD) Bond Program.

Harris County Engineer, John Blount submitted the grant application for this project to the TWDB. But the City of Houston became a “subrecipient” and is now managing the project.

Long Term Funding – Still A Missing Piece of Puzzle

Lake Houston, a City of Houston asset, is losing capacity. Everyone has recognized that fact for decades. But as silt filled the rivers, inlets and lake, maintenance was deferred, reportedly for budgetary reasons. In 2017, during Harvey, the problem became so big that no one could ignore it anymore. Flooding was the immediate problem. But loss of water capacity is an even bigger, longer-term problem.

It’s one thing to have a long-term maintenance dredging plan and another to put it into action. But where will the money come from?

A tax on sand mines? Won’t work. Most aren’t in the City. Or even in Harris County.

Some have suggested creating a taxing district for lakefront homeowners. That won’t work either. Not enough of them. And it would create a stampede for the Oklahoma border. Moreover, it hardly seems fair; the lake is part of a City system that provides water to two million people and generates revenue.

The logical solution seems to be increasing the cost of water. Adding just a fraction of a penny per 1000 gallons should do it. Dredging isn’t just about reducing flooding. Or preserving views for lakefront homeowners. It helps preserve the lake’s capacity. And that benefits everyone.

As we develop a long-term dredging plan for the lake, we also need to consider a sustainable source of financing.

Posted by Bob Rehak on 8/12/2020 based, in part, on a release by Houston Mayor Pro Tem Dave Martin

1079 Days after Hurricane Harvey

NHC Gives 40-50% Chance of Tropical Cyclone Formation In Gulf This Week

NHC Special Tropical Weather Outlook NWS National Hurricane Center Miami FL 805 AM EDT Sun May 31 2020 For North Atlantic, Caribbean Sea and Gulf of Mexico:

Source: National Hurricane Center 5 Day Tropical Outlook for Atlantic as of 7:05AM CDT on 5/31/2020

The National Hurricane Center (NHC) forecasts the Eastern Pacific Tropical Storm Amanda, now centered inland over southeastern Guatemala, to weaken into a remnant low or dissipate over Guatemala or southeastern Mexico by tonight.

However, the NHC also predicts that the remnants of Amanda will move northwestward within a broader area of disturbed weather, possibly emerging over the southeastern Bay of Campeche on Monday.

If the remnants move back over water, environmental conditions appear conducive to support some redevelopment of the system while it moves little through the middle of this week.

Regardless of redevelopment, heavy rainfall is likely to continue over portions of southern Mexico during the next few days. For additional information on the rainfall threat, see products from your national meteorological service.

The next Special Tropical Weather Outlook will be by 3 PM EDT today, or earlier if necessary.

  • Formation chance through 48 hours…medium…40 percent.
  • Formation chance through 5 days…medium…50 percent.

 If it does become a named storm, it would be Cristobal.

Tropical Storm Amanda will likely cross into the Gulf of Mexico on Monday. (Source: NOAA via Space City Weather).

Too Early to Predict Direction of Storm

Jeff Lindner, Harris County Flood Control District meteorologist, says, “Where exactly any center forms will determine what sort of longer term track would be possible … across the Gulf of Mexico.”

“Regardless of development,” he continues, “a large plume of tropical moisture will be moving into the SW and eventually the western Gulf of Mexico this week. Some of this moisture will likely get directed toward the Texas coast by late week and next weekend.”

“As with any tropical system in this stage of potential development, there is lots of uncertainty.”

“The best course of action is to monitor weather forecasts daily and National Hurricane Center outlooks for any changes.”

Jeff Lindner, Harris County Flood Control meteorologist

Preparedness

Hurricane season starts tomorrow. The NHC predicts above-average activity this hurricane season.

Source: National Hurricane Center prediction on 5/21/2020.

Now would be a good time to prepare. The major risks in the Lake Houston area include river and street flooding (as we saw with Harvey, Allison and Imelda) and wind damage (as we saw with Ike). Ike led to prolonged power outages due to trees falling against power lines.

Make sure you have fresh batteries and a backup supply, as well as a weather radio.

Also make sure you have a way to charge your cell phone (vehicle or power block). And make sure you learn how to use the Harris County Flood Warning System to increase your situational awareness.

Familiarize yourself with the LINKS page of this website. It contains links to many useful sites specializing in preparedness and weather.

Remember: the COVID crisis presents an extra layer of complication this year.

Lake Level Report

As of this morning, the level of Lake Conroe was 200.23 feet and the SJRA continues releasing 1581 cubic feet per second. Their goal: to bring the lake down to 200 feet by tomorrow.

Also as of this morning, the Coastal Water Authority indicates that the level of Lake Houston is down approximately one foot.

Lake Level41.46 ft.
Normal Pool42.4 ft.
Source: Coastal Water Authority readings as of 7:30am 5/31/2020.

Posted by Bob Rehak on 5/31/2020

1006 Days after Hurricane Harvey