Chuck Gilman Archives - Reduce Flooding

What Happened Downstream During Harvey as Lake Conroe Released 79,000 CFS

Last night, I posted some statistics about Lake Conroe levels after the SJRA started the release during Hurricane Harvey. Tim Garfield and R.D. Kissling, two top geologists, now retired from one of the world’s largest oil companies, have looked at the release from a downstream perspective. Last year, they put everything they learned into this 69-page presentation delivered to the University of Houston Honors Program.

*From “A Brief History of Lake Houston and the Hurricane Harvey Flood,” by Tim Garfield and RD Kissling with help from Bob Rehak, 2019.*

Recap of Key Points About Lake Conroe Release

To recap several key points:

The SJRA never did let Lake Conroe rise to its allowable flowage easement. The water level in Lake Conroe peaked at 7 a.m., August 28, 2017, at 206.23 feet. The SJRA’s flowage easement is 207 feet.
Outflow exceeded inflow by 8:30 a.m. on the 28th and stayed that way for the duration of the storm. As the lake level declined, the lake had up to 3 available feet of storage capacity.
Yet the SJRA kept releasing, on average, 2X – 10X more water than it was taking in. At one point, the ratio exceeded 100:1.

Tracking the Release Down West Fork

Garfield notes that the discharge ramp up that began the evening of the 27th reached a peak discharge rate of more than 79,000 cubic feet per second (cfs) just before noon on the 28th. The discharge rate didn’t dip below 70,000 cfs until 4 a.m. on the 29th – more than 16 hours later.

Following in lockstep with the Conroe release, flow rates at downstream gauges ramped up, in lockstep. By lining up the peaks of gages downriver, you can literally see the water surging down the West Fork all the way to Lake Houston. (See left side of image above.)

Significantly, Garfield says, these gauges all showed flattening flow-rate curves before the release ramp up. Those curves then turned and steepened upward as the Conroe release pulse arrived at those gauges.

Timing and Impact of Release in Lake Houston Area

Peak flow at the Humble gauge was reached shortly after noon on the 29th, roughly 24 hours after peak discharge was reached at the dam and roughly 30 hours after the high-rate release ramp up began.

Water started creeping under the doors of Kingwood Village Estates, a senior living center in Kingwood Town Center about 1.4 miles from the West Fork, at 3 a.m., on August 29th, 2017. It kept rising all morning and finally stopped another mile further inland. Water entered the last (highest) house to flood in Kings Point (the Kingwood subdivision closest to the main body of Lake Houston) at 2 p.m. that same day, according to Elise Whitney Bishop.

Residents trying to escape as Harvey's floodwaters rose — *Kingwood Village Estates residents trying to escape as Harvey’s floodwaters rose. Twelve later died.*

The level of upper Lake Houston, as measured at US59, rose an additional 7 feet during this period.

Significant additional flooding of Kingwood homes can be tied to this same period of increased discharge.

Flow rates measured at the Grand Parkway gauge and calculated at the Humble gage indicate a flow rate increase in this period of between 70,000 to 80,000 cfs, corresponding closely to the 79,000+ peak flow rate added by the Conroe dam discharge.

“The data from the affidavits further supports several key conclusions from the Harvey Flood Fundamentals section of our University of Houston talk,” said Garfield. Those include:

The large sustained release from Lake Conroe made West Fork flooding worse. The extra 80,000 cfs increased the West Fork flow 50%.
The release occurred as the storm was abating. It significantly increased flood damage in the Lake Houston area.

*More than 4,400 structures flooded in Humble and Kingwood along the West Fork. Source: HCFCD.*

The list of damages ran well over a billion dollars.

The SJRA Argument

The SJRA maintains to this day that Lake Conroe is a water-supply reservoir, not a flood-control reservoir. See the affidavits of Hector Olmos and Chuck Gilman. Olmos is a consultant who helped design the operations manual for the gates at Lake Conroe. Gilman is the SJRA’s Director of Flood Management, hired the year after Harvey.

They are basically claiming, “We don’t have the right tool to prevent downstream flooding.”

Editorial Opinion

Editorial opinion: That excuse has always sounded hollow to me. It attempts to curtail discussion of whether the SJRA waited too long to start releasing water, released too much at the peak, and then kept on releasing too much for days.

That discussion is a matter of public concern that could save lives and property in the future. We need to have it.

Sadly, it will take the courts to figure this out. In the meantime, the SJRA has hired some of the highest priced lawyers in the country and now appears to be angling for legislative immunity by hinting at higher water prices “statewide” if liability can’t be controlled.

It all smacks of similar arguments in other industries. If you’ve lived long enough, you’ve heard them all before, such as car companies that would be driven out of business if forced to install seat belts and other safety features. Well, that prediction didn’t quite work out! Luckily, for General Motors, the addition of safety features helped fuel its resurgence.

Posted by Bob Rehak on 6/12/2020 with thanks to Tim Garfield and RD Kissling

1018 Days after 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.

Operational Statistics from Lake Conroe Dam During Harvey Raise Troubling Questions

Two affidavits in a lawsuit filed against the SJRA for flooding downstream residents during Harvey contain statistics that raise several troubling questions about the operation of gates during the storm.

Did the SJRA wait too long to begin releasing water in significant volumes?
As a consequence, did it create an unnecessarily high peak discharge?
Did it maintain high discharge rates longer than it needed?
As lake levels declined, why did the SJRA continue releasing 2X to 10X more water than it was taking on when it had up to 3 feet of storage capacity in the Lake Conroe?
Why did it never let the level of Lake Conroe reach its flowage easement max?
Could different procedures have reduced downstream flooding?

*Part of one page of seven pages of gate operation statistics in affidavits.*

Affidavits of Gilman and Olmos Contain Insights

The first affidavit comes from Chuck Gilman, the SJRA’s Director of Flood Management. It contains a gold mine of statistics. Tables at the end of the affidavit show the date, time, average lake level, total inflow, and total discharge (cubic feet per second), and the exact time of gate changes. The statistics start August 26, 2017 at 10 p.m. They end three days later at the same time. The seven pages of statistics capture a snapshot of the storm and the SJRA’s response hour by hour during Harvey. At the peak, the SJRA recorded changes every 15 minutes.

The second affidavit comes from Hector Olmos, a Principal and Vice President of consulting firm Freese and Nichols, Inc. Olmos helped develop the gate operations policy for at Lake Conroe for the SJRA. The Olmos affidavit contains the same statistical information in Gilman’s. However, it also contains more details of the Gate Operations Policy in place at the time of Harvey. And the two affidavits assert different facts.

Download Gilman Affidavit

Download Olmos Affidavit

Inflow Vs. Outflow and Flowage Easement Max

In the summary that follows, outflow vs. inflow rates are significant. Gilman swore in his affidavit that the gate operation “…policy is programmed so that even in the most extreme situations, peak outflow will never exceed 70% of inflow.” “Peak” is the key word there. Olmos swore in his affidavit that 80% was the limit. However, statistics show that it never significantly exceeded 60%.

As you review the following, keep in mind another key point. SJRA had the ability and authority to increase the lake level to 207, but stopped short at 206.23 for some reason that the affidavits don’t explain.

Summary of Key Statistics and Actions

Key statistics show that:

Lake Conroe started to rise at 11:30 p.m. on August 26, 2017 in response to 1,722 cfs flowing into the lake.
After the lake level reached 201.04 feet at 12:15 a.m. on August 27, SJRA first opened its gates at 12:25 a.m. and started releasing 529 cfs.
After that, inflow generally increased for the next 24.5 hours, though the increases were not a straight line. Inflow fluctuated up and down, likely in response to feeder bands passing over the watershed or variations in readings due to wave and wind action.
More than 24 hours after the start of the storm, at 1 a.m. on August 28, inflow peaked at 129,065 cfs. By then, the lake level had reached 205.65 feet and the SJRA was releasing 62,082 cfs, less than half of the inflow.
From that point on, the inflow generally declined, but not in a straight line.
The water level in Lake Conroe peaked six hours later at 7 a.m., August 28, at 206.23 feet. That’s roughly three-quarters of a foot BELOW the SJRA’s flowage easement.
After that, water continued to go down for the duration of the storm, but the SJRA continued increasing its release rate for five more hours, until 12 noon on the 28th. The water level was 206.17 feet, almost a foot below its flowage easement. Inflow was 63,986 cfs (less than half the peak), yet discharge peaked at 79,141. So the lake level and inflow were going down, but the discharge rate kept increasing when the lake had room to spare.
SJRA kept the release rate above 70,000 cfs until 4:15 a.m. the morning of the 29th, more than 16 hours. By then, the lake level had gone down to 204.58. And the discharge rate was still three times higher than the inflow (71,538 cfs discharge vs 20,287 inflow).
For the rest of the storm, lake level, inflow rates and discharge rates all continued to decline. The table ends at 10 p.m., August 29th. Lake level equaled 203.44, discharge 22,033, and inflow 6,579.

Turning Points in the Storm

During the entire day of August 27th, outflow fluctuated roughly from 16% to 50% of inflow as the inflow kept building relentlessly.

Outflow exceeded inflow by 8:30 a.m. on the 28th and stayed that way for the duration of the storm even though the lake had up to 3 available feet of storage capacity.

By the morning of the 29th, downstream areas were flooding badly. The SJRA had roughly three feet of extra storage capacity in Lake Conroe within its flowage easement. Yet it kept releasing, on average, 2 – 10X more water than it was taking in. At one point the ratio exceeded 100:1.

Could the SJRA have used more of Lake Conroe’s available storage capacity as lake levels declined to help reduce downstream flooding?

Neither Mr. Gilman’s, nor Mr. Olmos’ affidavits shed light on these issues.

Please Note

Chuck Gilman inherited this problem. The SJRA did not hire him until well after Harvey.

Also note that conditions during an emergency can be chaotic. Keyboard quarterbacking after the fact is much easier.

If the SJRA wishes to respond to this post, I will print its position verbatim.

Posted by Bob Rehak on 6/11/2020

1017 Days after 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.

SJRA Adopts Modified Lake Lowering Program

In a marathon meeting last night, the SJRA modified the seasonal lowering program for Lake Conroe. The adopted motion does not exactly follow the City of Houston’s last-minute compromise recommendation. It delays lowering the lake to 199.5 feet until after September 1 to accommodate boaters and businesses on Lake Conroe. The City had recommended lowering the lake to that level beginning August 1. The old policy called for lowering the lake all the way to 199 in both months.

Details of Plan

Minutes of the meeting have not yet been approved, but here is the preliminary summary:

Spring lowering:

Lower to 200’ msl (mean feet above sea level) beginning April 1 through May 31. Recapture begins June 1.

Fall lowering:

Beginning August 1, lower to 200’ msl.
Beginning September 1, lower to 199.5’ msl.

Tropical Storm Provision:

If a named storm enters the region, City of Houston may initiate an additional prerelease to 199’ msl by requesting the SJRA to do so in writing. SJRA staff will coordinate with COH staff on the details and timing of the lowering.

Duration of Program

The program will continue through December 2022, giving the City of Houston enough time to add additional gates to Lake Houston and complete West Fork dredging.

1400 Crowd Convention Hall for 5-Hour Meeting

More than 1400 people crammed into the meeting at the Lone Star Convention Center in Conroe. The meeting lasted more than five hours. Some people arrived hours earlier to make sure they got seats.

*Estimated crowd of 1400. White shirts from Lake Houston, red from Lake Conroe.*

Lake Conroe residents still outnumbered Lake Houston residents by 2 to 1, but it was far better than the 20 to 1 ratio in previous meetings on this topic.

Also present at last night’s meeting were people from between the two lakes in communities such as River Plantation. More than 1100 people between Lake Conroe and Lake Houston flooded during Harvey when the SJRA released 80,000 cubic feet per second.

*Flooded Protester at February SJRA Board Meeting*

Plea for Civility Starts Meeting

The meeting started with a plea by the chambers of commerce from the two areas for unity and civility. And the meeting was in fact far more civil than previous meetings on this topic. Gone was the bar room atmosphere of jeers, catcalls, name calling, interruptions, and physical threats.

Staff Presentation and Mayor’s Letter Change Debate

Before public comments began, two developments totally changed the debate. Most people expected the SJRA to decide between continuing or scrapping the existing plan. However, the evening before the meeting, Houston Mayor Sylvester Turner sent a letter to the SJRA suggesting a compromise proposal: 200 msl in the spring and 199.5 in the fall. Then Chuck Gilman, SJRA’s Director of Water Resources and Flood Management, kicked off the meeting with an alternate proposal: 200 msl in spring AND fall.

Gilman’s presentation to the board emphasized lowering the lake one foot could have prevented releases in all but three storms in the last twenty years. Gilman’s team correlated the average rise in lake level per inch of rainfall in dozens of events. See graph below.

SJRA data shows that 1-foot of extra lake level (yellow line) would handle all but three storms that occurred in last 20 years. Hurricane Harvey was excluded from graph because it was considered an anomaly.

“A review of historic rainfall data and corresponding lake rise suggests less than 2 feet of storage is adequate to catch most storm events at Lake Conroe that occur in the fall,” said Gilman.

“Only two rainfall events that occurred in the months of August and September since 1999 (excluding 2017) resulted in more than one-foot of rise in Lake Conroe. More than 90% of these events resulted in less than 3 inches of rise in Lake Conroe. Five named tropical storms in this same period resulted in less than 12 inches of rise,” he said.

Many residents in attendance questioned why the SJRA excluded 1994 and Harvey from examination in the chart above. The worst downstream damage occurred during those two events.

Both the City’s proposal and the SJRA’s came as surprises to many people. Instead of choosing between A and B, suddenly C and D became options, too.

Board Settles on Compromise to Mayor’s Compromise Proposal

In the end, the proposal adopted by the SJRA differed from the City’s in one key respect. The level of Lake Conroe remains a half foot higher in August to accommodate boaters during vacation season. SJRA Board President Lloyd Tisdale characterized August revenue as vital to the area’s economy. Tisdale said vacationing falls off significantly after Labor Day.

Board member Kaaren Cambio who represents the Lake Houston area preferred the Mayor’s proposal but acknowledged that the final plan “balances flood mitigation with water supply and recreation. The board heard businesses and delaying the fall release will extend the boating season.”

The approved plan still lets the City of Houston call for lowering to 199 msl if forecasters predict a named tropical storm will enter the region within five days.

The City owns two thirds of the water in the lake. City Council Member Dave Martin said in his remarks before the board voted that “The City could take the lake down to 180 msl if it wanted.”

In the end, it appeared that the Board punted any responsibility for painful reductions and put that onus on the City.

State Emphasizing Need for Cooperation within Watersheds

Much of the board’s debate focused whether to adopt the City’s proposal verbatim. Board President Tisdale’s opening remarks cited the importance of partnership with other entities in the region. Legislation adopted in 2019 places a premium on cooperation within a watershed. The Texas Water Development Board can financially penalize those that don’t cooperate. They now score grant requests based on how well all affected areas work together. “We have to look at this as a regional flooding issue,” said Tisdale.

Upstream/Downstream Split

Both Lake Houston area Board Members, Kaaren Cambio and Mark Micheletti, argued for adopting the City’s plan, but none of the other board members agreed. In the end, they voted to adopt a plan that delayed lowering the Lake to 199.5 until September 1.

Net Effect Vs. Historical Averages

After a debate going back to 2018, we now have a lake-lowering plan that closely mirrors Mother Nature’s. Unless we’re in a very wet or very dry year.

Compared to historical averages, the SJRA will lower Lake Conroe:

4 to 5 inches in April and May
0 inches in August
3 inches in September

*Historical monthly lake level averages since Lake Conroe was built. Variation due to evaporation and rainfall rates.* *Source: SJRA January 2020 Board Presentation by Chuck Gilman.*

Of course, that assumes the City does NOT call for greater reductions. Also keep in mind that these are averages, not certainties. If the lake levels are higher or lower than the average in any given year, these reductions would vary.

The primary protection provided by the policy adopted by the SJRA would occur in a very wet year when the lake was full up to 201 msl. Then the reduction would be 12 inches in August and 18 in September.

State Representative Dan Huberty who gave a powerful speech before the board began deliberations, said, “I am proud of our community and how we came together, including the State (Especially Governor Abbott and Chief Nim Kidd), the City, the County, our Chamber and most importantly our citizens.”

Huberty continued, “Thank you for showing up and being respectful but forceful. We worked very hard, and in the end won a vote that achieves our goal of lake lowering. Special thanks to Mark Micheletti and Kaaren Cambio for having the courage to stand up with and for the recommendation from Mayor Turner and Mayor Pro-Tem Martin.”

The City of Houston provided no comment.

Posted by Bob Rehak on 2/21/2020

906 Days after Hurricane Harvey

SJRA Board Votes to Maintain Lake-Lowering Policy for Another Year

At its February 28th meeting, the San Jacinto River Authority voted to maintain its lake-lowering policy for another year. The policy calls for lowering Lake Conroe one foot below normal pool level (from 201 feet to 200) during the wettest months in Spring and two feet during the peak of hurricane season.

Extra Safety from Flooding

Until other mitigation measures can be put in place, the plan gives downstream residents an extra measure of safety from massive releases like those experienced during Hurricane Harvey. Those include dredging and additional flood gates for Lake Houston.

This is good news for the Lake Houston Area where Harvey made approximately 11,000 people homeless overnight.

Complaints from Lake Conroe Association in January Meeting

The Lake Conroe Association set the stage for conflict last month. The Association testified that last year’s lowering had a negative impact on business and home values in the area. They also maintained that the Board had acted unilaterally – without consultation – and that the project was only supposed to last through the end of dredging.

Having been at last year’s meeting where the proposal was discussed, I would disagree with these statements. The board considered dredging and gates for Lake Houston. The board also acted on the report of a consultant hired to review the proposal.

Mark Micheletti, a SJRA board member, said the board had received no complaints from businesses on the lake and that a check with realtors found no negative effect on home prices.

Reportedly, the Lake Conroe Association had also collected signatures on a petition asking for the policy to be reversed. At today’s meeting, the room was crowded with spectators, but I did not see the Association’s president, Mike Bleier. The association presented no petition.

The cataclysmic impacts on Lake Conroe’s economy did not materialize. Because of evaporation, the lowering really only amounted a little more than a foot in the fall.

Speaking for Kingwood

During the public comment section of the meeting, three Kingwood residents, Bill Fowler, Amy Slaughter and I, spoke FOR continuing to lower the lake. So did one Lake Conroe resident who flooded during Harvey.

I pointed out the fact that dredging was NOT yet complete and that the river still had an exaggerated flooding response to moderate rainfalls because of sediment dams. Fowler talked about normal evaporation levels in the lake and how the lowering was not as great as the targets would imply. Slaughter mentioned the impact of flooding on her family and recent Supreme Court rulings on inverse condemnation.

The Lake Conroe resident said he wished the Lake were lowered year round. He flooded during Harvey and thought that the lower levels would actually help Lake Conroe home values.

“But what if there’s a drought?”

When it came time to speak AGAINST the lowering, one man spoke up. He used water conservation as his main argument and posed the specter of drought.

When the board began debating the measure, Jace Houston, SJRA’s general manager, pointed out that many people misunderstood the measure. He said that the SJRA was not going to lower the lake beyond the 1- and 2-foot levels in the policy. If the lake was already down a foot due to evaporation, for instance, the SJRA would release no additional water.

Chuck Gilman, Director or Water Resources and Flood Management, thenshowed a series of slides that led to discussions about:

Lake-lowering strategy
Progress of the current West Fork dredging and Lake Houston Gates projects
Rainfall averages and historical lake levels by month
How the lowering and subsequent raising of the lake worked last fall
Staff recommendations

*Graph presented by Chuck Gilman showed how gradual lowering and natural refilling of Lake Conroe worked last year.*

*Gilman also showed a slide discussing the status of additional gates for Lake Houston.*

To see all the slides in the original high-resolution PDF format, click here.

Brenda Cooper, a new SJRA Board Member, then mentioned that some Lake Conroe residents had approached her to voice their disapproval of the project.

Motion Passes Unanimously

Board President Lloyd Tisdale finally called for a voice vote. “All members present voted FOR the lowering,” said Mark Micheletti, one of the Lake Houston Area’s two members on the SJRA board. “The vote could not have gone better from the Lake Houston area’s perspective.”

The SJRA will continue to lower Lake Conroe seasonally. The measure will come up for discussion again next February.

Community Reaction

Bill Fowler, Vice Chair of the Lake Houston Area Grass Roots Flood Prevention Initiation, said, “I was impressed by the Board’s firm grasp of the importance of lowering Lake Conroe on a seasonal basis for downstream residents. Their willingness to help until permanent solutions can be implemented impressed me.”

Kaaren Cambio, another SJRA board director from the Lake Houston area, said, “I’m happy that the board is balancing the needs of both upstream and downstream communities.

Amy Slaughter, the Kingwood lawyer whose home flooded badly, said, “They did the right thing.”

Posted by Bob Rehak on February 28, 2019

548 Days After Hurricane Harvey

Three New SJRA Flood-Management Actions

SJRA Flood Gate at Lake Conroe

In a motion approved at its 4/26/2018 board meeting, the San Jacinto River Authority (SJRA) officially entered the flood management business. The SJRA board also introduced the man, Chuck Gilman, who will head its new Flood Management Division. In a third major decision, the SJRA board voted to seasonally lower the level of Lake Conroe to help provide a larger buffer against future flooding.

New SJRA Flood Management Division Established

The SJRA board tasked its new flood management division with identifying “projects and other actions that may be undertaken by the Authority to address flood events along the San Jacinto River and protect the lives and property of Texans living within the watershed.” The FloodManagement Division will also identify sources of funding for such projects and implement them. The SJRA Flood Management Division will examine both immediate and long-term solutions that address flooding along the San Jacinto.

The SJRA has already begun work on an area-wide study of such possibilities. They include, according to board members, additional detention, more gages to enhance flood warning capabilities farther upstream, and a new system to help predict when floods will crest at various places within the watershed.

Chuck Gilman named new Director of Flood Management

Charles R. “Chuck” Gilman, Jr., P.E., will head the new division as Director of Flood Management. Gilman has more than 20 years of experience in civil engineering.

“We are extremely pleased to be adding someone of Chuck’s caliber and experience,” noted Jace Houston, SJRA’s general manager.

Jason Stuebe, Humble city manager, agreed with Houston’s assessment. “I think he will really understand the flooding issues facing our region and be able to help develop meaningful solutions.”

Before joining the SJRA, Gilman served as Deputy Chief Manager of the City of College Station and Interim City Manager. During his time at College Station, he also served as the Assistant Director of Water Services, Director of Capital Projects, and Director of Public Works. His administrative expertise pertains to utilities, transportation, drainage, emergency planning and response, planning and zoning, and legislative and governmental affairs.

Gilman is a licensed Professional Engineer in the State of Texas and holds a Project Management Professional Certification from the Project Management Institute.

Seasonal Lowering of Lake Conroe

At its 4/26/2018 meeting, the SJRA Board also voted to temporarily lower Lake Conroe on a seasonal basis. Lowering the lake will help comply with Governor Abbott’s directive to minimize downstream flooding.

Said Mark Micheletti, one of the two new SJRA board members from Kingwood, “This is major initiative and it will provide temporary relief until permanent solutions are in place.”

Normally, the SJRA maintains the level of Lake Conroe at 201 feet above mean sea level (MSL).The board voted to lower Lake Conroe by one foot to 200 MSL from April 1 through May 31. The board also voted to lower the lake between August and October, the peak of hurricane season. Lowering would start on August 1, with a target of 200 MSL. SJRA would lower it another foot – to 199 MSL – between September 1 and October 31. It is unclear at this time whether additional rain that fell in late October would be released or whether it would be retained to begin bringing the lake back up to its normal level.

In summary, this keeps the lake one foot below normal in the spring, one foot below normal during August and an average of two feet below normal for most of September and October. This plan will be reviewed annually in February to make adjustments as needed.

At the Board Meeting, four Kingwood residents and a representative of the Lake Conroe Area Homeowners Association, all spoke in favor of temporary seasonal adjustments to the lake level as a way to mitigate flooding.

Not Yet a Done Deal

Kaaren Cambio, the other new SJRA board member from Kingwood, said, “The plan is contingent on approval from other bodies. The TCEQ must allow an exception for the diversion of water and the City of Houston will need to approve this initiative. Nevertheless, until permanent measures can be implemented, winning the SJRA board’s approval to lower the lake is a major step in the right direction.”

By Bob Rehak

Posted April 27, 2018, 241 Days since Hurricane Harvey

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