Create Land Bank for Future Flood-Mitigation Projects

Creating a land bank for future flood-mitigation could reduce mitigation costs, speed up projects, and protect the lives and homes of millions.

When we should acquire land for future flood mitigation.
When we usually try to acquire it.

Why Flood Mitigation Takes So Long and Costs so Much

Five and a half years after Harvey, officials are still struggling to finance many flood-mitigation projects. Part of the issue has to do with high land-acquisition costs for large, stormwater detention basins and for widening channels.

The San Jacinto River Basin Master Drainage study recommended 16 such projects in the upper basin. The plan includes 10 large regional detention facilities comprising approximately 229,000 ac-ft and six channel projects covering about 38.5 stream miles. Total cost: $2.9 to $3.3 billion (including construction). Land acquisition comprises a large percentage of that total. To put that in perspective, 229,000 acre feet is more than half the capacity of Lake Conroe. And 38.5 miles is exactly the distance from downtown Conroe to downtown Houston. And the cost totals more than Harris County’s 2018 flood bond.

Acquisition costs can vary greatly depending on whether the land is rural or urban; in a flood plain or not; wetlands or not; at a low or high elevation; distance to market; highway access; and other factors.

Ironically, the SJRA studied some of the same recommended detention basins along Spring Creek and its tributaries more than almost 40 years ago. A 1985 study on the Upper River Basin included a chapter on planning. It recommended…

“Right of way and reservoir land acquisition should occur while the land is open and available.”

1985 San Jacinto Upper Watershed and Drainage Improvement Study

Had people only listened, taxpayers might have saved a billion dollars or more. Land costs then were a small fraction of today’s. Only 1.8% of the watershed was developed. So why didn’t the interested parties start buying the land back then?

How Benefit/Cost Ratio Can Disincentivize Planning

Even though the costs were far lower, the benefits of buying farm or timber land were even lower still. Developments had to creep much closer before the Benefit/Cost Ratios increased enough to justify the expenditures. But of course, at that point people were already flooding or in danger of flooding. Now, repetitive payouts from the National Flood Insurance Plan help document the “benefits” of buying the land.

So why not create a land bank for future flood mitigation projects?

  • Buy the land when it’s cheap.
  • Put it “in the bank.”
  • Build detention basins on it when needed.

Land-Bank Precedents

There are precedents for this idea.

  • USDA started its Soil Bank in 1956. Basically, it pays farmers to take land out of production to support crop prices and farm income while preserving soil.
  • Land banks around the world acquire, hold, manage, and sometimes redevelop property for productive use and to meet community goals, such as increasing affordable housing or stabilizing property values.
  • Wetlands mitigation banks help preserve valuable wetlands to mitigate damage associated with new developments
  • HCFCD’s Frontier Program buys up land in rural areas, then develops flood mitigation projects on it. The District sells “detention capacity” to developers to help reduce its costs. This also ensures sufficient capacity for planned developments and optimum efficiency for flood-control projects.

In a similar vein, why not create land banks for flood-mitigation?

The genesis of the idea came from an observation about the two areas under consideration now for two floodwater detention basins on Spring Creek.

Forty years ago, when these projects were first studied, the benefit/cost ratio didn’t justify the purchase. Fast forward.

Benefits of Land Bank

Now, we’re looking at purchasing the same land, but because of inflation and development, the land cost is vastly higher. Had the land been purchased and “banked” way back then, the results would have been:

  • Reduced flooding
  • Reduced damages
  • Reduced costs
  • Floodplains preserved
  • People out of harm’s way.

By waiting until land is developed and people flood, we get to pay twice – for their land and for their damages through the NFIP. And project length can drag out for decades.

To be eligible for the proposed flood-mitigation land bank, the land would have to be:

  • Near a stream or river
  • Suited for building flood-mitigation projects (i.e., have the right topography)
  • In or around growing areas, such as Houston, where it would be needed for flood mitigation in a reasonable number of years.

If it contains forests or wetlands, it gets bonus points because its already reducing flooding.

In summary, the idea is to reduce future costs by purchasing land (at market rates) when it’s cheap. It has the added benefits of:

  • Preserving floodplains, wetlands and forests
  • Preventing flood damage
  • Shortening the time needed to develop mitigation projects

How Much Flood Damage Could Have Been Prevented?

The United States needs to re-engineer its flood-mitigation business processes. Flood mitigation takes costs too much and takes too long because we wait too long.

The San Jancinto River Master Drainage Plan released in 2020 points out significant flooding in 1940, 1960, 1973, 1994, 2016, 2017, and 2019 along with numerous other smaller flood events. We’ve been studying the problem for more than 40 years without actually mitigating it. A flood-mitigation land bank could help reduce costs speed up mitigation, and protect people before they flood.

It would be interesting to calculate how much damage could have been prevented in the last four of those floods had all the projects in the 1985 plan been implemented.

Posted by Bob Rehak on 12/28/2022

1947 Days since Hurricane Harvey

MoCo District Judge Slams Door on Subsidence Deniers

In a devastating ruling for Quadvest, L.P., and Woodland Oaks Utility, L.P., John Delaney, visiting judge in the 284th District Court in Montgomery County, rejected their pre-trial arguments and granted a summary judgment that validated the San Jacinto River Authority’s Groundwater Reduction Plan (GRP) contract. Both Quadvest and Woodland Oaks have been subsidence deniers in the past.

The key to reducing subsidence in Montgomery County. SJRA water treatment plant at Lake Conroe Dam. Image courtesy of SJRA.

The only question now is whether the SJRA’s water rates are fair. However, Jace Houston, SJRA general manager, points out that SJRA makes no profit from selling water and that the defendants have cost the river authority more than $12.7 million by withholding contractual payments due under the GRP contract.

Other signers of the contract who did not contest it have had to pick up the slack for Quadvest and Woodland Oaks, placing an unfair burden on them. Both companies are private companies that pump groundwater in Montgomery County.

Excessive groundwater production in Montgomery County has been linked to subsidence and flooding there and in Harris County.

Content of Rulings

In a terse, one paragraph order, the judge ruled that the arguments, pleadings, papers and evidence of Quadvest and Woodland Oaks should be denied under applicable law. Delaney signed the order on December 16th, 2022.

In a separate order on the same day, Judge Delaney ruled on the defendant’s defenses. Quadvest and Woodland Oaks claimed:

  • Lack of consideration
  • Failure of consideration
  • Fraud
  • Illegality
  • Mutual Mistake

In the second order, the Judge simply stated that those defenses were DENIED.

The order concluded, “The Court has determined as a matter of law that “SJRA’s GRP Contracts are incontestable, valid, and enforceable according to their terms.”

Why Contract is Incontestable

State law makes it clear that when a contract is signed that relates to a bond offering and which has been approved by the State Attorney General, the contract is incontestable. In this case, the SJRA issued $550 million of bonds and the Texas Attorney General approved the contract.

SJRA used the bonds to build its surface water treatment plant on Lake Conroe and a distribution system. The distribution system also required acquiring rights of way.

“Consideration” received by the 80 entities signing the contract included:

Quadvest and Woodland Oaks claimed they received no consideration because LSGCD had since changed its rules after the current Board became elected in 2018 – thanks in large part to major contributions by Quadvest.

The goal of reducing groundwater usage was an attempt by suppliers in the region to reduce subsidence.

Since 2020, Quadvest and Woodlands Oaks have refused to pay the rate due under the contract, but have continued to charge their customers as if they are abiding by the contracted amount. 

Jace Houston, SJRA general manager, points out that the defendants had 30 other groundwater reduction plans they could have joined back in 2010 (when the contract went into effect) if they felt they weren’t getting fair consideration.

Subsidence reduced, then leveled off for several years after the contract. However, it is now accelerating again thanks to virtually unlimited groundwater pumping by Quadvest and others.

Second Lawsuit Still Winding its Way Through Courts

Although the ruling applied only to Quadvest and Woodland Oaks, it also has implications for two other entities, the Cities of Magnolia and Conroe.

Both signed the SJRA GRP contract. And both withhold payments. Magnolia is currently $800,000 in arrears and Conroe owes $15.8 million. With Quadvest and Woodland Oaks, that brings the total owed to the SJRA up to $29.3 million.

However, Magnolia and Conroe are not making the same claims as the two private entities. They claim “governmental immunity.”

Interestingly, the attorney general is worried about such claims BETWEEN governmental entities. If for some reason a judge allows the claim, a high percentage of regional water supply contracts in the State of Texas could become unenforceable, according to Mr. Houston. As a result, the Texas Water Development Board has stopped making loans and grants to entities in breach of such contracts. Interestingly, of the 80 parties signing the SJRA GRP contract, virtually half are governmental entities of some sort.

Next Steps

“Quadvest and others have tried for years to cloud the issues and confuse the public about the GRP Contracts, and today all of that has been put to rest,” said Mr. Houston.  “Decisions up to this point have been on pre-trial matters such as jurisdiction and venue. We are pleased to have a ruling on the merits that declares the GRP contracts valid and incontestable in any court.”

“Any further proceedings in Montgomery County should only be to verify that the rates are reasonable,” said Houston. “We look forward to presenting to the court how SJRA takes great care to prepare a very conservative and reasonable budget, and charge rates that are ultimately voted on by our customers.”

Judge Delaney’s rulings, though not directly on the subject of subsidence, have the potential to impact it. Without a financial incentive by companies like Quadvest to deny subsidence, perhaps the LSGCD board will quit trying to deny it, too.

Posted by Bob Rehak on 12/21/2022

1940 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.

New NASA Satellite Will Measure Changes in Earth’s Rivers, Lakes, Oceans

Early in the morning on December 16, 2022, NASA launched a new satellite that will map and subsequently measure changes in virtually all of the Earth’s rivers, lakes and oceans. High-resolution imaging will even be able to measure changes in ocean currents and temperatures. Scientists will use the imaging capabilities to better understand flooding, droughts and coastal erosion. One said it will “revolutionize hydrology.”

About the Satellite and Orbit

The satellite will orbit more than 550 miles high. Nicknamed SWOT (Surface Water and Ocean Topography), the mission will cover the globe between the Arctic and Antarctica at least once every three weeks.

About the size of a SUV, the satellite will measure the height of water on more than 90% of Earth’s surface. It will enable scientists to track water flow and identify potential high-risk areas.

SWOT’s dual antennas at work. Image Credit: NASA.

The heart of the improvements is an innovative instrument called the Ka-band radar interferometer (KaRIn) – a major technological advance. KaRIn bounces radar pulses off the water’s surface and receives the return signal using two antennas on either side of the spacecraft. 

According to NASA, for the first six months after launch, SWOT will be in a “fast-sampling” phase with a 1-day repeat orbit. Objectives in this phase include calibration and validation while studying rapidly changing phenomena.

The next phase – Operations & Sustainment – should last about three years It will have a 21-day repeat orbit to balance global coverage and sampling. NASA chose this “non-sun-synchronous orbit to minimize tidal aliasing and ensure coverage of major water bodies on land.” SWOT’s 75-mi-wide swath will result in overlapping measurements over most of the globe with an average revisit time of 11 days.

For a discussion of “tidal aliasing,” see this article in Geophysical Journal International. It’s about overcoming errors in current models that have to do with undersampling, uncertainty, imperfections and low-resolution.

Scientists Describe Anticipated Benefits

Scientists working on the mission described anticipated benefits:

  • Larry Smith: “Through acquisition of high-resolution, spatially continuous measurements of inland water surface elevations, SWOT stands poised to revolutionize terrestrial hydrology in much the same way that Seasat transformed physical oceanography in 1978.” 
  • Mike Durand: SWOT will help us “better understand how precipitation is partitioned (runoff, evapotranspiration, storage).”
  • Colin Gleason: “SWOT’s downstream estimates of river discharge will form perhaps the world’s most complete accounting of human alteration of river flow.”
  • Marc Simard: It will tell us “where surface water flows and where it is stored, everywhere on Earth.”
  • Doug Vandemark: “New data will aid existing weather prediction models in terms of how they resolve and predict heat and energy exchange between the atmosphere and oceans in both fair and foul weather situations.”
  • Demitris Menemenlis: SWOT will give us “increased predictive skill for weather forecasting.”
  • David Sandwell: It will “improve our mapping of the marine [environment] by perhaps a factor of 5.”

For More Information

To learn more, check out the following:

SWOT is a joint effort of NASA and the French space agency CNES, with contributions from the Canadian and United Kingdom space agencies.

Posted by Bob Rehak on 12/18/22

1937 Days since Hurricane Harvey

Demolition of old KMS Complete

This week, contractors completed the demotion of the old Kingwood Middle School (KMS). This clears the way for construction of the new, larger, permanent stormwater-detention basin and rebuilding of athletic fields in front of the new KMS. Even the foundation has been removed.

Photos Taken Dec. 17, 2022

Demolition of old school complete. Looking NW toward Woodland Hills.
Looking East. Note temporary detention pond alone Pine Terrace on right.

Looking N toward new school
Looking west toward Woodland Hills at what will become the new athletic fields.

The old Kingwood Middle School was the first middle school in Kingwood and served Kingwood students for 45 years. Humble ISD built it in 1977.

Andrew Wells was the first principal. He subsequently became principal of Kingwood High School and served there for 20 years.

With completion of the demolition of the old KMS, a piece of Kingwood history is gone. But a new chapter begins with a gorgeous new showcase that speaks for the resilience and quality of one of the finest communities in southeast Texas.

Progress of Construction in Photos

For photos showing the progress of KMS construction and demolition, see below.

I can’t wait to see this project when it is complete!

Posted by Bob Rehak on 12/17/22

1936 Days since Hurricane Harvey

Public Comment Period on Taylor Gully-Woodridge Village Plan Open to December 28

Last night, Harris County Flood Control District (HCFCD) revealed its long-awaited recommendations to reduce flood risk along Taylor Gully. The recommendations involve channel improvements, another Woodridge Village stormwater detention basin, and a new bridge at Rustling Elms.

HCFCD is seeking public comment on the plan through December 28, 2022.

Outline of Recommended Alternative

Excessive runoff from Woodridge flooded hundreds of homes in Elm Grove, North Kingwood Forest, and Mills Branch twice in 2019 after a developer clearcut 270 acres without sufficient mitigation.

To fix the problem, HCFCD examined four different alternatives outlined in this presentation, but recommended Option 1. It includes building:

  • A concrete-lined, low-flow channel within the existing channel to expand conveyance from 350 feet downstream of Creek Manor Drive to 1500 feet downstream of Mills Branch Drive. The concrete portion would be four feet deep and 20 feet wide.
  • An additional dry-bottom, 412.5 acre-foot detention basin on the northern portion of the site.
  • A new clear-span bridge at Rustling Elms to replace the current bridge over two culverts.
Four-foot-deep, 20-foot-wide concrete channel-in-a-channel (not drawn to scale) would expand conveyance without expanding current width of main channel.
Scope of recommended alternative. Does not show work on E&R contract already underway or replacement of Rustling Elms bridge. But those would be included.

The recommended alternative would not require any right-of-way acquisition. Translation: no buyouts required.

166% Increase In Stormwater Detention Capacity

Not shown in the diagram above is the stormwater detention basin that Sprint Sand and Gravel is currently working on. Under the terms of their excavation and removal contract with HCFCD, the contractor has up to three years to excavate 500,000 cubic yards. A spokesperson for HCFCD said, “We expect that they will excavate the full amount. The E&R area, like the existing Perry Homes basins, will eventually connect to or become part of the Woodridge detention-basin network to complement the recommended alternative.”

Five hundred thousand cubic yards equals 309 acre feet. With the new pond, that would add 721 acre-feet of stormwater detention to the existing site. The site currently has 271 acre feet of detention. So, the detention volume would increase 166%. It only needed to increase 40% to meet Atlas-14 requirements. Net: the recommended fix should create a considerable margin of safety.

Not Included in Recommendations

The plan does NOT include any improvements near White Oak Creek at the downstream end of Taylor Gully. HCFCD determined that flooding at that end of the channel was caused by backup from White Oak and Caney Creeks.

Area circled in red floods from water backing up from White Oak Creek, not Taylor Gully.

However, discussion during the meeting suggested that the recommended detention basins further upstream on Taylor Gully could help that area to a minor degree. The plan primarily addresses flooding along and either side of the channel highlighted above to the left of the red circle.

Bridge Replacement

Because of the concrete-lined, low-flow channel conveyance improvements that are a part of the recommended alternative, the existing culverts at Rustling Elms Drive (below) would need to be replaced. See below. An open-span bridge like the one in the background would likely replace it. The current bridge built over culverts (below) backed water up considerably during the 2019 floods and contributed to flooding homes for several blocks on either side of it.

Rustic Elms Bridge on Taylor Gully
The bridge at Rustling Elms (foreground) caused backups after Woodridge was clearcut. This would be replaced.

Comparison of Alternatives

HCFCD recommended Alternative #1 because it removes the most structures, acres and roadway from the floodplain for the second lowest cost. Compare the alternatives below. For a fuller description of each alternative, including those not recommended, see the complete presentation.

Alternative #1 is recommended.

What Comes Next?

The sequence below outlines project steps. We are currently discussing the preliminary engineering phase. After public comments have been incorporated in that report, HCFCD will deliver it to commissioner’s court and begin final design.

After close of public comments, they will be incorporated into plan transmitted to Commissioners Court.

Then, the final design will begin for all improvements. Once complete, the final design will dictate final costs and timing.

To View Video of Meeting and Comment…

HCFCD wants your input. To review the hour-long video of the meeting and/or submit a public comment, see this page (F-14 Taylor Gully Flood Risk Reduction Project).

Review the entire presentation here.

Posted by Bob Rehak on 12/15/22

1934 Days since Hurricane Harvey

Recommended Floodgates Could Release at Rate of Lake Conroe During Harvey

City of Houston Mayor Pro Tem Dave Martin’s office has supplied ReduceFlooding.com with the Black & Veatch Engineering report on the recommended alternative for adding floodgates to Lake Houston. One key finding immediately jumped out at me that wasn’t in Martin’s press release last week. The recommended gates would have a release capacity that virtually equals the highest release rate of Lake Conroe during Hurricane Harvey.

The Lake Conroe release rate during Harvey maxed out at 79,000 cubic feet per second (CFS).

The eleven tainter gates recommended by Black & Veatch would have a release rate of 78,700 CFS.

New Possibilities, More Certainty

That opens up a world of possibilities. For instance, the City could wait to start releasing water until it knew water was coming downstream from Harvey.

Said Martin, “Once constructed, we can release with a moments notice which gives us great opportunities to coordinate release protocols with the SJRA!!”

Previously, Public Works has been reluctant to release water in advance of a storm because the release rate of the existing gates is so small. They have to start lowering the lake so far in advance of storms that a storm can veer away before it gets here. If it does, that means water has been wasted.

The recommended floodgates should provide much more certainty for operators and avoid waste.

Key Elements of Recommendation

site of proposed gates for Lake Houston on east side of dam
Gates would be placed at the original channel for the San Jacinto River seen in foreground.

Other key elements of the recommendation include:

  • Locating the floodgates in the earthen eastern portion of the dam near the old channel of the San Jacinto River.
  • Creating baffles and a dissipation basin downstream from the new gates to break up the flow and reduce water velocity
  • “Outdenting” the gates (i.e., building them in front of the current dam)
  • A bridge between the two parts of the earthen dam
  • Using tainter gates, the same type used at Lake Conroe.
  • A 3.5 year construction schedule.

The last point means that if construction started in January, the earliest completion date would be mid-2026.

However, given the need to line up additional funding in the state legislature, 2027 is a more realistic date.

For a complete discussion of the project history, constraints, alternatives, recommended options, construction drawings, rationales, and costs, see the entire 28-page Black and Veatch Report by Chris Mueller, PhD, P.E.

Posted by Bob Rehak on 12/14/22 based on the Black & Veatch Report

1933 Days since Hurricane Harvey

Last Reminder: Taylor Gully Meeting Wednesday 6:30 p.m.

Harris County Flood Control District will hold a virtual Taylor Gully meeting Wednesday, December 14, 2022 at 6:30 p.m. Purpose: to discuss the findings of its plan to reduce flood risk along Taylor Gully. Register at: PublicInput.com/taylor.

To learn more about the project scope, see this post. It discusses the related effort to virtually double detention capacity on the Woodridge Village Property that HCFCD purchased in 2021. Up to six hundred homes flooded in this area twice in 2019.

About Taylor Gully

The headwaters of Taylor Gully originally started where Woodridge Village is today, just north of the Harris/Montgomery County Line (tan area in map below). From there, it cuts through Elm Grove, Mills Branch and Woodstream Forest before joining White Oak Creek which then joins Caney Creek and the East Fork San Jacinto.

Taylor Gully/Woodridge Village
Project being discussed Wednesday night

Taylor Gully Meeting Details

The virtual community engagement meeting will be held on:

December 14, 2022, 6:30 p.m. – 7:30 p.m. 
Register/Join online at: PublicInput.com/taylor
Or join by phone* at 855-925-2801 with Meeting Code: 3364

The Taylor Gully meeting will begin with a brief presentation to share project updates, followed by a moderated Q&A session with Flood Control District team members. Residents will be able to submit questions, comments and input before, during and after the meeting, which will be considered during project development. Any comments not addressed during the Q&A session will receive a response at the conclusion of the public comment period.

Meeting Followup

Even if you are unable to attend the live meeting, residents are encouraged to register for the meeting to receive future project updates. A recorded version of the meeting will be available on the Flood Control District’s website and YouTube channel after the event. 

Special Needs?

Meeting accommodations can be made for those with disabilities. If needed, please contact 346-286-4040 at least three business days prior to the meeting. For questions, please contact the Flood Control District at 346-286-4000, or fill out the comment form online at hcfcd.org/taylor.

Posted by Bob Rehak on 12/13/22

1932 Days since Hurricane Harvey and 1181 since Imelda

Flood Map Accuracy

On December 6, 2022, The Washington Post ran an article titled “America Underwater: Extreme floods expose the flaws in FEMA’s risk maps.” The lengthy story by Samuel Oakford, John Muyskens, Sarah Cahlan and Joyce Sohyun Lee cross-referenced photos and videos with FEMA flood maps from areas around the country that flooded last summer.

The basic premise: FEMA’s flood maps “are failing to warn Americans about flood risk.” The authors then claim, “The resulting picture leaves homeowners, prospective buyers, renters and cities in the dark about the potential dangers they face, which insurance they should buy and what kinds of development should be restricted.”

There’s certainly room for improvement in FEMA flood maps.

FEMA Map from National Flood Hazard Layer Viewer. Note how mapping stops at Montgomery County line, one of the issues cited in The Post article.

But is Climate Change the Reason for Inaccuracy?

However, the authors blame climate change for the inaccuracy far more than other contributing factors which are far more obvious.

FEMA is supposed to update flood maps every 5-10 years. It’s hard to imagine climate change invalidating them in that time period.

Climate is an average of weather occurring over much longer time periods. Depending on whether you talk to a meteorologist or a geologist, the time period could range from 30 to millions of years.

At least five major ice ages have occurred throughout Earth’s history: the earliest was over 2 billion years ago, and the most recent one began approximately 3 million years ago and continues today (yes, we live in an ice age!). Currently, we are in a warm interglacial that began about 11,000 years ago. The last period of glaciation, often called the “Ice Age,” peaked about 20,000 years ago. At that time, the world was on average probably about 10°F colder than today.

Interestingly, one day after The Post article, the New York Times ran a story about the DNA of animals found frozen in the permafrost of northern Greenland, just a few hundred miles from the North Pole. The 135 different species scientists found there paint a picture of an arctic once lush with life typical of warmer climates today.

But another thing puzzles me. I see climate change often mentioned as the reason for drought. The US Geological Survey states, “Climate change has further altered the natural pattern of droughts, making them more frequent, longer, and more severe.” But The Post uses almost identical language to blame climate change for frequent flooding in many of the same general areas at the same time. Which is it?

And to what degree can climate change explain flood map inaccuracy? Many more obvious reasons exist that are less of a stretch for any inaccuracies.

Reasons Listed in Post Article for Inaccuracy of Maps

Here’s a list of the references in The Washington Post story used to explain inaccuracies found within FEMA maps. I’ve broken them into two groups so you can see the weight they gave to climate change.

Climate-Change References:
  1. “As climate change accelerates, it is increasing types of flooding that the maps aren’t built to include.”
  2. “Extreme precipitation events are growing increasingly common.”
  3. “A warming climate allows storms to carry more moisture, producing greater rain or snow in a short period of time.”
  4. “Climate has changed so much that the maps aren’t going to keep up.”
  5. Maps are out of date, some decades-old “in a changing climate.”
  6. “The effects of a changing climate.”
  7. Climate change impacts are getting worse.
  8. Climate change is “pushing FEMA’s maps beyond their limits.”
  9.  A gap exists between the data that goes into FEMA maps and current climate conditions.
  10. Climate change baseline is changing.
  11. “Climate change velocities are high.”
  12. “Maps do not take climate change into account.”
  13. “Overestimating the rarity of some events even before climate change…”
Other Possible Explanations Mentioned by The Post:
  1. “Communities may resist expanding designated flood zones because it adds costs and can hamper development.”
  2. Not all areas that flooded are mapped yet.
  3.  “Local communities often resist the expansion of federal flood zones”
  4. “Maps do not forecast flooding. Maps only reflect past flooding…”
  5. “Local governments have been opposed to any maps that show an increasing risk.”
  6. Relatively high imperviousness of gentrifying areas.
  7. Maps don’t reflect intense bursts of rainfall in a short period and the resulting street flooding.
  8. Impervious surface is replacing porous surface.
  9. Maps cover mainly coastal and riverine flooding.
  10. “Rain combining with melted snowpack.”
  11. FEMA flood maps don’t even attempt to model urban flooding
  12. “City neglected drainage problems.”
  13. Local opposition to expanding the floodplain.
  14. No sense of urgency to update maps.
  15. “Multiple compounding factors contribute to the flooding”

However, the article makes no mention of the mathematical limitations of Extreme Value Analysis, the key to understanding the uncertainties associated with rainfall probabilities.

Floods Can Also Be Explained Without Climate Change

The second group of references in The Post article seems far more immediate, compelling and easily provable when explaining any inaccuracy found in flood maps. They’re certainly typical of what I have found in the Houston area.

For the past five years I have been researching instances of flooding in and around Harris County. I published more than 250 articles on different aspects of the 2019 Elm Grove floods alone. And I don’t recall one person ever blaming those on climate change.

Elm Grove did not flood during Harvey, but did flood on two much smaller rains in 2019. The difference? Clearcutting and insufficiently mitigated upstream development. Contractors clearcut approximately 270 acres immediately north of Elm Grove without building sufficient detention capacity before the rains fell.

Similar stories – with variations – have played out over and over again throughout the Houston region. For instance, we see developers filling in wetlands. Exaggerating the infiltration rates of soils. Underestimating impermeable cover. Building in floodplains. Building to outdated codes and floodplain regulations. Being grandfathered under old regulations. Various jurisdictions refusing to update regulations. And more.

Regardless of your position on climate change, this discussion dramatizes the needs to:

  • Understand your local flood risk and the factors that affect it
  • Buy flood insurance.

Hopefully, Harris County Flood Control District’s MAAPnext project will address data deficiencies discussed in The Post article. But it will be years before those maps become official. And when they do, the landscape will have already changed.

Posted by Bob Rehak on 12/12/22

1931 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.

Can Cream City Teach Bayou City about Flood Mitigation?

The smell of ripe grass. The blinding purples, yellows, and whites of fall wildflowers. The buzz of pollinators deciding which stop to make next on the buffet. These are all elements of a strategic approach to flood mitigation across the Milwaukee, Wisconsin metropolitan area. 

Photo Courtesy of Matt Berg. Restored wet prairie in MMSD’s Greenseams program.

US Water Alliance’s One Water Summit Explores Greenseams Program

I was asked to join the Texas delegation at the US Water Alliance’s annual conference earlier this fall. The One Water Summit brings together a wide swath of the water sector in the name of planning and managing all water resources (drinking water, wastewater, and stormwater) as part of an integrated process. Since every single drop has value, it’s only logical to treat it that way.

The week included plenty of time thinking and planning with municipal water departments from Dallas, Austin, San Antonio, and Houston, but day one of the conference featured a number of field trips to different examples of the Milwaukee area’s water infrastructure. I chose to spend my afternoon learning about the Milwaukee Metropolitan Sewerage District’s (MMSD) Greenseams program. 

Conservation of Parcels with Low and High Infiltration Rates Help Manage Flood Peaks

There are two broad approaches at the heart of the program: 1) conserve land parcels that are wet under normal conditions or that hold water after a rain event and 2) conserve land parcels with high infiltration rates to get water in the ground quickly. In certain areas, wetlands and prairies also undergo restoration efforts to improve performance even further.

Working together, these approaches mean strategic locations slow and hold water upstream to reduce flood peaks downstream and release it gradually over time at a more manageable rate. This results in reduced flood risk for private property and public infrastructure. A natural approach to flood mitigation!

Financing Programs in Surrounding Counties

Milwaukee County’s location means it lies at the end of multiple rivers flowing together just before they enter Lake Michigan. That also means Milwaukee County and the City of Milwaukee are at the receiving end of every interaction between rainfall and land use upstream, including areas far outside their respective jurisdictions. 

As a result, MMSD uses a mix of grants, bond funds, and service fees to strategically implement its program and preserve land not just within its own service area but on upstream portions of watersheds in a handful of surrounding counties. This makes for greater impact in Milwaukee County and also introduces flood mitigation benefits for many more communities throughout a much broader swath of watersheds in the region.

Link Between Restoration and Reduction

For the field trip, our group visited a handful of adjacent former farm fields within the City of Franklin. Over the last couple decades, these have been restored to reintroduce prairie vegetation, reconnect historical hydrological features, and reduce erosion.

Photo Courtesy of Matt Berg. Restored prairie in MMSD’s Greenseams program.

As it so happened, our site visit took place just a day after one of the heaviest rainfalls in the region’s recorded history. Despite the downpour, the site was damp but entirely walkable, assuming you’re wearing something like hiking boots and not dress shoes! This site has moderately high infiltration rates, so water drains downward in a hurry. We saw photos from other sites that took the other approach and held substantial water on the surface before slowly releasing it downstream. We very much saw the action in real time. 

Beyond Flood Mitigation to Water Quality Improvements, Too

It doesn’t end with flood mitigation, either. Depending on the characteristics of each site in the program and its conservation agreement, there are additional big benefits via ensuring clean drinking water, preserving wildlife habitat, and providing recreation opportunities for residents and visitors. 

At the City of Franklin site we visited, it was obvious the rapidly developing surrounding area was already planning for additional trails to connect new neighborhoods to the site’s open space. 

How Ideas Could Translate to Houston

You may be thinking that sounds all well and good for Milwaukee, but how about the Southeast Texas?

Houston locals spend a lot of time talking about the impermeable soils of our region. Yet according to the U.S. Department of Agriculture’s Natural Resources Conservation Service, the soil infiltration rates (how fast water moves down through the soil) of Harris County and Milwaukee County are actually quite comparable.

Granted, data from the National Weather Service’s Atlas 14 makes it clear that the intensity of rain events in Houston is much greater than in Milwaukee. 

However, two more things that Houston and Milwaukee do have in common are increasing trends in precipitation intensity and a rapidly growing urban footprint. These two compound each other, with heavier rainfall on ever greater hard surfaces causing more and faster runoff. 

Photo Courtesy of Matt Berg. Pickerelweed in Panther Branch watershed in Montgomery County, TX.

MMSD works with local land trusts in its region to make Greenseams a success. In the Houston region, groups like Bayou Land Conservancy, Coastal Prairie Conservancy, Galveston Bay Foundation, and Houston Audubon all play big roles in delivering benefits for flood mitigation and clean water supplies through land conservation from the very top of to the bottom of our region’s watersheds.  

Photo Courtesy of Matt Berg. Riparian wetland along Spring Creek on the border between Harris County and Montgomery County.

The need is definitely present, and the pieces are there to make it happen. I guess you could say it sure “seams” like heartily pursuing such a regional strategy would be a great idea for Southeast Texas too. 

By Dr. Matthew Berg, CEO & Principal Scientist, Simfero Consultants. Posted on 12/9/22

1928 Days since Hurricane Harvey

Note: Milwaukee is known as Cream City for the distinctive light color of the bricks produced there and widely used in its architecture.

Save the Date: HCFCD Releases Details of Taylor Gully Meeting

On Dec. 2, I printed a story about an upcoming virtual community meeting on Taylor Gully. At the time, Harris County Flood Control District (HCFCD) had not yet released details yet on how to attend. They have now. See their press release below. Please share it with family, friends and neighbors if you live anywhere along Taylor Gully. That includes parts of Sherwood Trails, all of Elm Grove, all of North Kingwood Forest, parts of Mills Branch, Woodstream Forest, and even parts of Porter in Montgomery County. Yes, plans will affect Porter also.

Map of Project

Map of project from HCFCD.org

Virtual Community Engagement Meeting for the
Taylor Gully Flood Risk Reduction Project

HCFCD PROJECT G103-80-03.1-E001

BOND PROJECT F-14

The Harris County Flood Control District will hold a community engagement meeting for the Taylor Gully Flood Risk Reduction Project. The purpose of this meeting is to inform residents about the project’s status, share project information and gather important community input on this effort.

The Taylor Gully Flood Risk Reduction Project focuses on improvements to Taylor Gully and the mitigation required to build the project. This project will be partly funded through the 2018 Bond Program, which was approved by Harris County voters on August 25, 2018. Community engagement is a foundational component of the Bond Program, and we invite your participation and input as projects are implemented.

Register Now

The virtual community engagement meeting will be held on:

December 14, 2022, 6:30 p.m. – 7:30 p.m. 

Join online at: PublicInput.com/taylor

Or by phone* at 855-925-2801 with Meeting Code: 3364

The meeting will begin with a brief presentation to share project updates, followed by a moderated Q&A session with Flood Control District team members. Residents will be able to submit questions, comments and input before, during and after the meeting, which will be considered during project development. Any comments not addressed during the Q&A session will receive a response at the conclusion of the public comment period.

Even if you are unable to attend the live meeting, residents are encouraged to register for the meeting to receive future project updates. A recorded version of the meeting will be available on the Flood Control District’s website and YouTube channel after the event. Meeting accommodations can be made for those with disabilities. If needed, please contact 346-286-4040 at least three business days prior to the meeting. For questions, please contact the Flood Control District at 346-286-4000, or fill out the comment form online at hcfcd.org/taylor.

Esta reunión de participación comunitaria se llevará a cabo en inglés; sin embargo, el Flood Control District proporcionará intérpretes de idiomas y materiales traducidos a pedido. En caso de necesidad, comuníquese al 346-286-4040 al menos tres días hábiles antes de la reunión.

*If you attend by phone only, maps and other exhibits will not be visible. However, information will be available after the meeting on the project webpage at hcfcd.org/taylor.

Posted by Bob Rehak on 12/8/2022 based on a press release from HCFCD

1927 Days since Hurricane Harvey and 1176 since Imelda