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Time is Enemy of Flood Mitigation

Everyone says, “It’s not if, but when we will flood again.” Most people would therefore deduce that “Time is the enemy of flood mitigation.”

The Maryland Reminder

We were reminded of that this week with the horrific images of flash floods raging down Main Street of a small Maryland town. It was the town’s second so-called “thousand-year storm” in 22 months. Just two weeks ago, the Federal Emergency Management Agency awarded the state and county more than $1 million to pay for projects aimed at reducing the flood risk in areas around Main Street. The project had barely begun when the second storm hit, wiping out the town again and killing at least one person. Luckless residents lamented how they had already spent their life savings to fix up their homes and businesses after the first flood.

Reason for Count-Up Calendar on This Site

Yes, time is the enemy. That’s precisely why I have put the count-up calendar at the top of every page on this website and why I sign off every post with the number of days since Hurricane Harvey.

I would urge you to do the same every time you contact friends, colleagues and representatives. Remind them how long it’s been. Don’t let people forget.

Official Start of Hurricane Season

Today is the official start of another hurricane season. Already one tropical storm, Alberto, narrowly missed us before the season even began. So where do major flood mitigation projects stand for our area?

Where Major Projects Stand

The Army Corps of Engineers delayed the opening of bids for the West Fork dredging project until June 12. They expect the project to take through the end of the year … just to go from River Grove Park to the West Lake Houston Parkway Bridge.

The TCEQ is still trying to decide whether to allow the SJRA to lower the level of Lake Conroe during the peak of hurricane season … which, if historical averages hold, would amount to a whopping 4.8 inches (because evaporation usually lowers Lake Conroe already by more than 1.5 feet due to evaporation).

Harris County plans to issue a $2.5 billion flood bond on August 25th, the anniversary of Harvey. Harris County Flood Control is currently defining projects within that fund and soliciting community input on them. (Please come to the Kingwood meeting at the Community Center on June 14 at 6pm.)

Flood gate additions for Lake Houston? See below.

The Flood-Gate Gauntlet

The City of Houston and Harris County Flood Control hired a consultant to evaluate the idea of adding more flood gates to Lake Houston to increase the discharge capacity during floods.

Then the city filled out a three-page Notice of Intent for the Texas Division of Emergency Management (TDEM). TDEM is part of the Texas Department of Public Safety. A Notice of Intent is like an application to fill out an application! The TDEM uses it to evaluate eligibility of an application before the City goes to all the time and expense of actually filling out the real application.

In May, Houston City Council Member Dave Martin notified the public in his newsletter that, “The Notice of Intent was recently approved by the Texas Division of Emergency Management. The City of Houston is now working diligently to complete this application and submit for selection.”

Currently Working on Application

Stephen Costello said, “TDEM has approved the gates project to go to the application phase. We are meeting with Tetra Tech this week (May 7) to discuss timing of application preparation and submittal. Either way we plan on having all resilience projects applications submitted no later than end of August.”

The City must still submit the real application to TDEM. TDEM prioritizes applications based primarily on benefit/cost analysis. TDEM sends those that provide the most benefit for the buck to the Federal Hazard Mitigation Grant Program (HMGP) within FEMA. FEMA, of course, is within the Department of Homeland Security.

Submittal Hopefully before End of August

Dave Jackson, Chairman of the State Hazard Mitigation team at DPS, has stated that Texas will send $1.2 billion worth of recommended projects to FEMA by August 25th, the anniversary of Harvey.

“If TDEM approves the project application, TDEM then prepares the grant paperwork for City of Houston acceptance,” says Matt Zeve of Harris County Flood Control who has recently submitted 15 other mitigation projects himself. “That’s when the local match is actually encumbered.” HMGP projects work on a 75/25 split. That means that if the gates cost $47 million, the City must put up almost $12 million that becomes legally reserved for the project.

Grant Approval and Lining Up Funding

It’s unclear at this time where those matching funds will come from. If they come from Community Development Block Grant Disaster Recovery (CDBG-DR) funds, those funds have not yet been released by the Federal Government and probably won’t be until November. The CDBG-DR, of course, is administered by yet another agency of the Federal Government – Housing and Urban Development. However, at least one Federal official thinks the City may also be able to use some funds left over from debris cleanup for the match.

Engineering and Construction

Once the monies are committed and plans approved, the Army Corps of Engineers, part of the Department of Defense, gets involved! I am told that the Corps would approve the engineering of the new flood gates.

Shepherding projects such as this one through the federal gauntlet requires constant supervision. Ted Poe and our senators have asked all departments involved to expedite the project. However, Ted Poe retires at the end of this year and either Todd Litton or Dan Crenshaw will replace him. Both would be freshman legislators.

And don’t forget time for environmental studies and comments.

Ted Poe’s Chief of Staff is optimistic though. “With luck, construction could begin in two years,” said Tim Tarpley.

The Case for Process Re-engineering

If ever I saw a classic case for the need to re-engineer business processes, this is it. For the gates, A TIME-SENSITIVE PROJECT, we have involved or will involve:

The City of Houston
Consultants
The Mayor
City Council Members
City Engineer
The Texas Division of Emergency Management
The Texas Department of Public Safety
The Governor of Texas
Federal Hazard Mitigation Grant Program
FEMA
Department of Homeland Security
U.S. Army Corps of Engineers
Department of Defense
Community Block Grant Development Disaster Recovery Fund
Department of Housing and Urban Development
U.S. House of Representatives
U.S. Senate
Cabinet Secretaries
Agency Heads
Countless staff members at every entity above
Environmentalists

Could we possibly make this multi-jurisdictional morass more complicated? A Rubic’s Cube has fewer facets!

After Pearl Harbor, it took approximately 3.5 years to win World War II. Anyone want to bet on how long it will take to add flood gates to Lake Houston?

Posted June 1, 2018 by Bob Rehak

276 Days Since Hurricane Harvey

Harris County Flood Control Solicits Ideas for Flood Bond Package on New Portion of Website

Harris County Flood Control District has just launched a new portion of its website designed to explain the proposed $2.5 billion flood bond package. Residents will go to the polls on August 25, the anniversary of Hurricane Harvey, to vote on the package. For details about the bond package, access the site at https://www.hcfcd.org/bond-program/.

The site is organized by all watersheds in Harris County. For people new to the Lake Houston area, we live within the San Jacinto watershed. Within each watershed, the site also talks about:

Potential project types
Community engagement meetings
Community input
Frequently asked questions

One of the more interesting features of the site is an interactive map with icons representing the locations of potential projects. Clicking on an icon reveals the type of project under consideration at that location, the number of people affected and more.

Preliminary map of projects currently under consideration within the San Jacinto River Watershed.

Transparency and Equity Among Goals for Flood Bond

Remember several important things: In addition to flood mitigation, two goals of this project are transparency and equity. The county wants to ensure that the bond money helps each watershed throughout the area, and that money is spent in ways that will help the largest number of people and yield the greatest benefit. That’s why you see the population numbers for each watershed and the number of people affected by each project as you click on icons throughout the map.

More Projects Than Dollars To Do Them

The county has far more potential projects than dollars. Some projects currently under consideration may not make the final cut. Likewise, other projects not yet listed could make the final cut. According to Matt Zeve of Harris County Flood Control, “Our staff is working furiously to define projects for the bond.”

Community Input Meeting for Flood Bond on June 14

Zeve says the County is also soliciting citizen input through community meetings and the website itself. Mark your calendar. One of the first meetings will be in Kingwood at:

Kingwood Community Center
4102 Rustic Woods Drive
Kingwood, Texas 77345

June 14, 2018
6 p.m. to 8 p.m.

Citizens can also submit input through the website.

“The Harris County Flood Control District accomplishes its mission by working with our partners and local stakeholders to evaluate, develop, and implement flood damage reduction plans and then perform long-term maintenance of drainage infrastructure,” says the site.

Flood damage reduction plans and projects can include:

Modifications of streams and bayous to increase the amount of stormwater they carry
Creation of detention basins to store excess stormwater
Nonstructural flood mitigation tools
Any combination of the above

Types of Flood Bond Projects Currently Under Consideration

Currently, the vast majority of projects fall into the following categories. Types of projects eligible for bond funding include:

Voluntary Home Buyouts – The purchase of flood-prone structures from willing sellers in areas that are too deep in the floodplain to benefit from structural flood risk reduction projects, or in areas where flood risk reduction projects are not feasible. This process includes the demolition of the structure and relocation of the seller to higher ground.
Storm Repair – Major maintenance projects that restore the designed function and capacity of a channel or stormwater detention basin.
Subdivision Drainage Improvement – Partnership projects with the Harris County Engineering Department and a Municipal Utility District to provide drainage improvements to subdivisions in unincorporated Harris County.
Local Projects – Flood risk reduction projects such as channel modifications or stormwater detention basin construction using only Harris County Flood Control District funds.
Partnership Projects – Flood risk reduction projects such as channel modifications or stormwater detention basin construction using a combination of Harris County Flood Control District funding and funding from local, state, or federal partners such as the Federal Emergency Management Agency.

Prioritization of Projects

Make sure you read the Frequently Asked Questions. One asks, “How will projects be prioritized?” Answer: “High on the priority list are construction-ready projects with federal funding partners (such as the U.S. Army Corps of Engineers and the Federal Emergency Management Agency) that give the County “the most bang for its flood control buck.”… Consideration is also given to areas that have a lower level of current protection as compared to other areas in the county.”

The county will give highest consideration to projects that meet the following criteria:

Provides the greatest potential flood risk reduction benefits relative to the community’s population
Causes NO increase in existing flood risks upstream or downstream
Offers potential for multiple benefits, in addition to flood risk reduction
Features long-term viability and relatively low maintenance
Includes a clearly defined drainage issue and flood risk reduction benefit
Uses readily available, proven engineering techniques and industry standards
Poses NO undue burden on disadvantaged communities
Minimizes adverse impacts on the environment

Submit Your Flood Bond Ideas Now

If you have ideas to contribute, submit them now so that they can receive the full consideration they deserve. Remember: when it comes to “equity,” historically the San Jacinto watershed has received 0% of flood mitigation budgets, but we suffered 13% of the damage in the region during Harvey. For an excellent discussion of equity and needs throughout the region, see the Greater Houston Flood Mitigation Consortium’s report.

The consortium’s report provides an excellent summary of the needs of the San Jacinto watershed.

Posted on May 31 by Bob Rehak. Thanks to Clay Crawford the tip.

275 Days since Hurricane Harvey

San Jacinto West Fork Emergency Dredging Project Details

The U.S. Army Corps of Engineers has posted bid specifications for its emergency dredging project on the West Fork of the San Jacinto River between Humble and Kingwood.

Bid documents available publicly online reveal details, maps, scope and timing of the project. Specifications, maps and amendments total more than 300 pages. See highlights below.

Start and Completion Dates

Opening of bids for the San Jacinto River Emergency dredging project, originally scheduled for May 29, has been moved to June 12, 2018. The U.S. Army Corps of Engineers expects to award the job shortly after bids are opened.

The winning bidder is expected to commence work within five calendar days after the award of the job. The winning bidder is also expected to complete the work within 180 calendar days from the award. That would put the new completion date in mid-January 2019. The core expects bidders to staff the project sufficiently to complete work within that time.

From River Grove Park to Just Beyond
West Lake Houston Parkway Bridge

The project will focus on the area from River Grove Park in Kingwood to slightly east of the West Lake Houston Parkway bridge.

Dredging will start near River Grove Park and end just east of the West Lake Houston Parkway Bridge.

The objective: to restore the main river channel to pre-Harvey conditions by removing sand and other debris, such as dead trees, that obstruct the flow of the river.

Removal and Storage Methods

Sediment may be excavated or dredged mechanically. Regardless of how it is removed, it must be placed in one of two designated sand pits. The first is between Townsen and the West Fork, east of US59 and Wilson Road. The second is west of US59, between Sorters Road and the West Fork, south of Kingwood College.

Sediment will be transported via pipeline or trucks to one of two sand pits for permanent storage.

The disposal area south of the river will be filled first – up to the existing ground elevation. When the pit is filled, it will be graded to prevent ponding and make sure it drains toward the San Jacinto River.

The remainder of the sand will go to the second site near Sorters Road. It is unclear at this point whether enough sand will be dredged to fill those pits.

Restoration

Neither sand, nor other debris, will be stored on the river’s banks where it could be washed back into the river.

Fences, roads, ditches, private or public grounds, and other structures or improvements damaged as a result of the contractor’s operations must be repaired or rebuilt at the contractor’s expense.

If fresh deposits from new storms during the term of the project require additional dredging, the Corps will expand the scope to include those.

To view the full specs, visit this site: https://govtribe.com/project/usace-west-fork-san-jacinto-river-emergency-debris-removal-harris-county-texas.

Questions? Ask the Corp Directly

The Lake Houston Area Grassroots Flood Prevention Initiative will be hosting a meeting June 11 from 6:30 to 8 p.m. at the Kingwood Community Center, 4102 Rustic Woods, 77339. So mark your calendars and plan to attend.

Eduardo Irigoyen, Project Leader for the U.S. Army Corps of Engineers’ San Jacinto River West Fork Dredging Project, will discuss the project and take questions.

Additionally, the Flood Prevention Initiative organizers will provide updates on other important issues. They include the potential lowering of Lake Conroe during August and September (as well as next April and May), dam upgrades for Lake Houston, and the upcoming Harris County Flood Mitigation Bond Election.

The meeting is free and open to the public.

Posted May 30, 2018 by Bob Rehak

274 Days since Hurricane Harvey

Where do you live relative to official flood plains?

During Harvey tens of thousands of people in the Houston area outside of 100-year and 500-year flood plains flooded. Do you really know your home’s location relative to official flood plains? It could be important during lesser floods and affect the cost of flood insurance.

This FEMA web site shows interactive flood plain maps that can give you a wealth of information about the risk to your property.

Feature-rich, Interactive Flood-Plain Map by FEMA

Access FEMA’s Flood Zone map for this area by going to this web page: http://maps.riskmap6.com/TX/Harris/

Then follow these steps:

When you get to the entry page, agree to terms and conditions
Type in your address to get a detailed view of risk for yourself and your neighborhood. Or you can also type in something more general, such as Kingwood TX, to see the contour of flood plains in the entire community.
On the left-hand panel, check both boxes under “Effective Flood Insurance Rate Map.”
The legend is on the right. Some explanations:
1. Anything in solid purple is in the FLOODWAY. Expect frequent flooding and major damage.
2. Anything under the fuchsia diagonal stripes is in the 100-year plain. People there have a 1% probability of flooding every year – and a 26% chance of flooding during the life of a 30-year mortgage.
3. Anything under grey diagonal stripes is in the 500-year flood plain. People there have a 0.2% probability of flooding every year – and a 5.8% chance of flooding during the life of a 30-year mortgage.
4. Properties outside those zones are in an area of overall lower risk. Lower-cost, preferred-rate, flood insurance policies (known as Preferred Risk Policies) are often an option in these areas. See your local insurance agent or visit floodsmart.gov for more information.
If you entered your specific address, click the info button above the map, then click the star on your property to learn more about your risk. After the box pops up, you can click “View Detailed Flood Report” for even more information.
You can hide both the legend and check box panels by clicking on the >> double arrows at the top of each panel.
Zoom and move about, as you would Google Maps.
Use the measuring tool above the map to check your distance from flood zones and hazards such as streams, ditches and rivers.

Guide to Terminology

If you need help interpreting all the acronyms and technical language in the check boxes and legend, consult this PDF: How to read a FEMA Map

The PDF above is definitely worth a read. It explains the “language” of flooding and flood insurance. It also explains how to protest a designation if you think the map has misclassified your property, for instance, if your slab has been elevated relative to the average level around you.

Experiment with the different tools and views in the map. Zoom out to see the risk in surrounding areas. The interactive exploration is fascinating.

Regardless of how far you are from flood plains or how high you are above them, if you live in Harris County, seriously consider flood insurance. During Harvey, more homes flooded outside the 500-year flood plain than inside.

A Less Powerful, but Easier-to-Understand Alternative

Harris County Flood Control offers a web site similar to FEMA’s; it has fewer options and less information, but is easier to understand and navigate. It’s actually called a “flood education mapping tool.” See: http://www.harriscountyfemt.org/Index.aspx.

The flood education mapping tool from Harris County Flood Control District has fewer options but is easier to understand.

How to Find the Elevation of Your Home

If you don’t already know the elevation of your home from surveys, deeds or insurance docs, try this web site: https://elevationmap.net/.

My thanks to Paul Margaritis, a long-time Kingwood resident. Paul forwarded this information to RefuceFlooding.com.

Posted 5/29/2018 by Bob Rehak

273 days since Hurricane Harvey

Debris Removal from Lake Houston Begins

Debris removal from Lake Houston has begun. On Sunday, May 27, I received a brief note from Keith Jordan, a Kingwood resident who has been active in flood recovery. His note said, “Toured the river today. Saw two barges with cranes picking up large piles of tree debris along the banks, but no dredging occurring.”

A few hours later, I received another note from Dianne Lansden, co-chair of the Lake Houston Area Grass Roots Flood Prevention Initiative. She forwarded a newsletter to me from State Representative Dan Huberty. The newsletter quoted statements from Houston Mayor Sylvester Turner and Houston City Council Member Dave Martin about debris removal.

Removing Dead Trees

Turner stated, “I’m pleased to inform you that debris removal operations on the Lake Houston Reservoir began last week with the goal of preventing flooding and improving the use of the lake for recreational purposes and as key water supply source.”

The flood associated with Hurricane Harvey destroyed thousands of trees, which are now being removed from Lake Houston.

“Houston debris contractor DRC Emergency Services, LLC is performing the work with four barges and is expected to add two more by June 1, 2018. There are an estimated 75,000 to 150,000 cubic yards of debris in the lake because of Hurricane Harvey, according to the City’s debris monitoring operator, Tetra Tech. Removal of debris will reach 2,000 cubic yards per day at the height of operations,” said Turner.

At that rate and depending on the actual amount of debris recovered, the project could last anywhere from approximately five to 10 weeks.

During floods, dead trees like those shown above can wash downstream. The debris can then collect at at bridges and dams, impeding the flow water. as Kingwood resident Dave Seitzinger showed. Such piles of trees can work much like beaver dams.

Separate from Army Corps Dredging Project

Apparently, this project is separate from and in addition to the dredging project that the U.S. Army Corps of Engineers is studying.

Mayor Turner continued, “This project, when combined with the dredging of the San Jacinto River, provides that residents’ tax dollars are being used in a most beneficial manner to protect their properties from high water.”

Temporary Lowering of Lake Houston For Debris Removal

Dave Martin, District E Houston City Council Member said, “This week, residents can expect to see the level of Lake Houston reduced due to needed maintenance for the health of the Lake Houston Spillway Dam. In order to conduct this work the Coastal Water Authority will need to reduce the level of the Lake from 42.36 ft to 42.0 ft. This reduction in lake level will only be temporary while maintenance is occurring, and residents should not be alarmed. The purpose of the maintenance is to allow crews to remove debris that is currently sitting on top of the dam.”

Progress!

Posted on May 28, 2018 by Bob Rehak

272 Days Since Hurricane Harvey

The Nine-Month Anniversary of Harvey

Today marks 270 days since Harvey devastated one of the most beautiful communities in America. This weekend is the nine-month anniversary, the official start of yet another hurricane season, and Memorial Day. So it seems only fitting to look back.

The street in front of Jennifer Trimble’s home as she and her son were being rescued by boat.

Paul Margaritis, a friend and neighbor sent me the video below as a reminder.

WoodsEstatesDebris

It shows a one-block drive down Woods Estates in Kings Forest (one block west of Kingwood High School and north of Kingwood Drive). However, it could be any street in the Lake Houston Area shortly after Harvey. I remember not even being able to get into many neighborhoods because of all the debris cascading into streets. Foster’s Mill, Kingwood Lakes, and parts of Kings Point come to mind. Debris and vehicles completely filled the streets and blocked traffic.

Nine months later, the heartbreak has gone indoors, but it’s still there. You can see it in campers parked in driveways – where people are living as they complete repairs. You can see it in “Now Open” signs that have just appeared on retail establishments. You can see it in building permits, dumpsters, contractor pickups, and port-o-lets still occupying people’s yards.

Home, Home on the Driveway! The Slaughter family has been living in a trailer for 9 months as they try to restore their home.

And all too frequently, you can see scenes, such as this – a grim reminder of the recovery that just never seems to end.

Repair work continues at the home of a Kingwood business owner who has been living out of a hotel for nine months now.

Most people that I talk to who were flooded still only live in parts of their homes – if they’re in their homes at all. If you ask when they expect their homes to be fully restored, they may smile and say, “By the end of summer.” But every time a contractor fails to show up for a week, they pray it won’t be the summer of 2020.

This is why we can never forget the destruction caused by Harvey and why we must press the fight for flood mitigation measures.

The cost of mitigation will be a tiny fraction of the cost of damages from flooding.

Had we followed the recommendations of engineers after 1994 and Allison, perhaps fewer people would have had their lives turned upside down by Harvey.

It’s both ironic and fitting that the 9-month anniversary of Harvey should happen on Memorial Day weekend.

Posted on May 26 by Bob Rehak

270 Days since Hurricane Harvey

Lowering Lake Conroe: How much is enough?

The president of the Lake Conroe Association has said the group will fight a reduction of their lake to 199 mean feet above sea level (msl) during September. Remember, SJRA normally maintains Lake Conroe at 201 msl.

“The fight can be avoided, and relief can be felt in the Lake Houston area, by accepting a more reasonable approach of temporarily lowering Lake Conroe by not more than 1 foot for flood control,” said Mike Bleier, at the bottom of his post: http://www.lakeconroeassociation.com/the-lca-will-lead-the-fight-against-lower-lake-levels/

Is Reducing the Lake Level an Extra Foot Worth the Fight?

Readers have asked, rightly so, “Is this worth the fight? How much would we really gain, especially considering that evaporation already reduces the lake to 199.4 msl on average during September?”

Depending on your perspective (and how far from the lake you live), you might say:

“That extra foot is not worth the fight, because nature will already likely give us most of it.”

Or…

“If another massive release from the dam is necessary, that extra foot, in fact, every inch, will save more homes and/or give us more time to evacuate. We need every inch and every second we can get in an emergency, especially considering that dredging has not yet started.”

Do you have your hurricane kit prepared? Do you have flood insurance yet?

The Value of an Extra Foot of Buffer

The extra foot would undoubtedly save some homes on the margin of the flood, because flood gates would not have to open as wide or as long or even at all. However, it’s impossible to precisely calculate how many homes would be saved. That’s because of all the sediment clogging the river and other unknowable factors such as rainfall distribution and duration, and ground saturation. However, it is possible to calculate how much time we could gain to evacuate safely.

How Much Time We Would Gain Before Flood Gates Had To Open?

Let’s compute it:

Lake Conroe covers 21,000 acres.
A one-foot reduction in its level equals 21,000 acre feet.
But flow and discharge rates are measured in cubic feet per second (CFS).
So let’s figure out what that would be, given a rainfall as intense as Harvey’s.
Converting acre feet to cubic feet…
There are 43,560 cubic feet in one acre foot.
21,000 x 43,560 = a total of 914,760,000 cubic feet being debated
The maximum inflow rate to the lake during Harvey was 130,000 cfs.
914,760,000 cf / 130,000 cfs inflow = 7,037 seconds
7037 seconds = 117 minutes = approximately 2 hours
A one foot reduction would provide an extra two-hour buffer against a rainfall as intense as Harvey’s.
How much buffer is there normally?
Gates must open when water level increases 18 inches above 201 feet.
Without lowering level of lake, we have a 3-hour buffer before gates must open.
Lowering the lake level one foot means there’s a 5-hour buffer before gates must open.
Lowering the lake level two feet provides a 7-hour buffer before the gates must open.

Jace Houston, general manager of the SJRA, confirmed these calculations. He also stated that they were generally consistent with the rate of rise that SJRA saw in Lake Conroe during Harvey.

Finally, Houston pointed out that few storms are as intense as Harvey, and that with smaller rainfalls, you would gain proportionally more time. For instance, half the inflow rate would double the buffer time.

Those smaller storms have a much higher probability of occurring. However, a 20-inch rain falling over a two day period would be classified as yet another 500-year storm.

In fact, as I write these words, a tropical system is brewing in the Gulf. The amount of expected rainfall associated with it is 15-20 inches at this moment. If it actually rains 20 inches, that would be exactly half the amount Harvey dumped on IAH.

According to Jeff Lindner of Harris County Flood Control, this storm is expect to slow near the cost and dump up to 20 inches of rain between NE Louisiana and the Florida Panhandle.

Keep in mind: that storm is NOT currently predicted to affect the Houston area. Forecasters believe it will make landfall between SE Louisiana and the Florida Panhandle. I’m using this only as a hypothetical example.

So, in our hypothetical example, let’s assume the inflow rate to Lake Conroe is exactly half of Harvey’s. That would give us twice as much time – 14 hours as opposed to seven to prepare. What would you need to do during that time if you were in an area that could flood?

Move your belongings to a higher floor if you have one?
Gather up your valuables, albums, computers, documents, medications, insurance policies, guns, etc.?
Refill prescriptions if you’re low?
Pack enough food and clothes for a week?
Gas up your vehicle with thousands of other people?
Pack up your vehicle?
Collect your children, elderly relatives, pets and all their medications and valuables?
Move additional vehicles to higher ground?
Find a friend or hotel who lives on higher ground who is willing to take in your family?
Investigate escape routes when the power may be off and trees may be blocking roads?
Move all that toxic stuff under your sinks and in your garage up into your attic?
Shut off your electricity?
Warn friends, neighbors, and relatives?
Let them know your evacuation plans?
Find an ATM with money left in it?
Beat the traffic out of town?

Sounds like a pretty full day to me! Granted, you might have a little more time because it takes water a while to get from Conroe to Lake Houston. But you might also have a little less time, because sand blocking the river could cause water here to rise faster, regardless of Lake Conroe releases.

So is that extra foot worth fighting for? In my opinion, yes.

It would let Lake Conroe absorb more water, decreasing the chances that they would have to open their flood gates. And if they had to open their flood gates, it would delay the opening, giving you more time to prepare to evacuate and get to higher ground.

Remember, if the rainfall rate was heavier, you would have even less time.

I didn’t have to evacuate during Harvey. The flood stopped one house away from me. So I would like to hear from those who WERE forced to evacuate? Do you think 7-14 hours would have helped? How would your life have changed if you had had that much time to prepare?

Posted May 25, 2018 by Bob Rehak

269 Days Since Hurricane Harvey

Results of May SJRA Board Meeting and Decision to Temporarily Lower the Level of Lake Conroe

At its May Board meeting, the San Jacinto River Authority (SJRA) chose not to reconsider its April decision to lower the level of Lake Conroe temporarily at the peak of hurricane season. The board also chose not to put reconsideration of the resolution on its agenda for next month. This now puts the decision about whether to lower Lake Conroe temporarily into the hands of the City of Houston and the Texas Council on Environmental Quality (TCEQ).

Protest by Lake Conroe Association

The Lake Conroe Association protested last month’s board resolution to temporarily lower the level of Lake Conroe by up to two feet in September. The resolution was intended to help protect Lake Houston area residents from flooding until other mitigation measures, such as dredging, can be implemented. The Governor specifically directed the SJRA to make such protection part of its mission.

However, the president of the Lake Conroe Association (LCA), Mike Bleier, urged the board to reconsider its decision and was given unlimited time to present his case. Bleier spoke for more than half an hour. Bleier’s main concerns were the potential impacts on recreation, home values and businesses around Lake Conroe. Several other members of the association spoke in support of reconsideration.

Kingwood Residents Speak in Favor of Lowering

More than a dozen Kingwood residents also attended the meeting. Four spoke in favor of letting the motion stand.

Guy Sconzo, former superintendent of the Humble Independent School District, thanked the board for its decision to lower the lake. Then he talked about the impact of flooding on Lake Houston area infrastructure. His talk addressed massive losses by the school district, Kingwood College, and more.

TxDoT hopes to repair damage to the I-69 bridge by September, more than a year after Harvey. In the meantime, residents endure massive traffic jams.

Robert Westover talked about a flooded retirement community where several elderly residents died due to injuries incurred during high-water rescues and related stress.

Amy Slaughter complemented the board for its decision to lower the lake and explained how it would help insure that people had time to rebuild while other flood mitigation measures were completed.

Dennis Albrecht, who owns homes on both Lake Houston and Lake Conroe also spoke. Albrecht compared the relative impacts of flooding and lower lake levels on home values. Albrecht pointed out that the value of his Lake Conroe home has increased steadily despite lower lake levels at times. He also pointed out the devastating impact of the flood on the value of his Lake Houston home. “There’s no comparison,” said Albrecht.

Many other Kingwood residents attended the meeting to support the SJRA Board’s decision.

When is a lowering not really a lowering?

Bleier said that his members would accept a one foot lowering, but not two. Several Kingwood residents pointed out that evaporation already typically reduces the level of the lake by more than a foot and a half during September. The LCA’s decision to accept a one-foot lowering was, therefore, actually no concession at all; they would likely give up nothing.

Assuming average loss due to evaporation, the actual lowering would amount to only 4.8 inches.

Dianne Lansden, co-chair of the Lake Houston Area Grass Roots flood prevention initiative, and I gave Bleier a tour of the devastation in Humble and Kingwood yesterday. After a two-hour tour, while professing to be sensitive to the needs of downstream residents, Bleier proceeded to tell us the concerns of upstream residents. Among them: his members might not be able to take their boats to lakefront restaurants. (Editorial comment: Spooky shades of Marie-Antoinette!)

Not All Lake Conroe Residents Support LCA

To be sure, not all Lake Conroe residents agree with Bleier. Hundreds of homes on Lake Conroe also flooded during Harvey and reportedly most of the owners also favor a temporary seasonal lowering of the lake level, according to SJRA Board Chairman Lloyd Tisdale.

Lake Lowering Could Still be Nixed

Despite the SJRA board’s decision this morning, Lake Conroe still may not be lowered. To take effect, both the City of Houston and the TCEQ must also agree to lower the lake. The City owns two thirds of the water in the lake. The TCEQ must decide whether any lowering will count as an emergency release or be deducted from the City’s draw rights. If not considered an emergency release, the City may not support the decision to lower the lake.

Uncertainty Surrounding Weather Outlook

Some forecasters are beginning to worry about a possible drought. As of May 22, Drought.gov pointed out that abnormal dryness is currently affecting approximately 13,612,000 people in Texas, which is about 54% of the state’s population.

However, NOAA issued an outlook saying that 2018 will be a slightly above average hurricane season.

And, Thursday night, the National Hurricane Center predicted a 90% chance of tropical development in the Gulf this weekend. That system could dump up to ten inches of rain on neighboring Louisiana and other gulf states.

How a 10-Inch Rain Could Affect Kingwood

If we got ten inches of rain from a storm, such as the one entering the Gulf this weekend, that could constitute a 50-year rain at a time when the river is clogged with sand. That could produce a higher-than-normal flood for that amount of rainfall, and re-flood parts of Kingwood and Humble before dredging could even begin.

Personal Recommendation

Personally, I favor lowering the level of the lake. The actual amount of manual lowering, assuming this is an average year, would be only 4.8 inches. Even in the depths of the 2011 drought, the loss of 4.8 inches would have not have been disastrous.

There’s little chance, despite the hyperbolic rhetoric from LCA that 4.8 inches will destroy the Lake Conroe area. And it could help protect the Lake Houston area from another disaster.

In fact, in eight of the last 18 years, Lake Conroe has lost more than two feet of water due to evaporation and the lake is still one of the state’s most desirable destinations for tourists.

LCA Vows to Escalate the Fight

LCA has vowed to press its fight with the City and TCEQ and claims to have enough political support lined up to kill the proposal to lower Lake Conroe temporarily.

So get involved. Urge the TCEQ, Mayor and City Council to TEMPORARILY lower Lake Conroe until other mitigation measures, such as dredging, take effect.

Posted on 5/25/18 by Bob Rehak

269 Days since Hurricane Harvey

Rainfall Rates, Durations and Frequencies for This Area

The upper Texas Coast is famous for intense, frequent rainfall. Sometimes, like during Harvey, rainfall can last for days. So how do you know when you’re experiencing something truly out of the ordinary? Consult the table below. This table relates three factors: rainfall total, rainfall duration, and rainfall classification. From this chart, you can see that all it will take for us to have our fourth five-hundred year storm in four years is about an inch an hour for 18 hours, or about two inches per hour for six hours.

Rainfall Rates, Intensities and Frequencies for The Woodlands Area on the West Fork, near Humble and Kingwood, Texas

What are the odds of getting hit with three 500-year storms in three years (which we did in 2015, 2016 and 2017)? One might think they are 1 in 125 million which was computed by multiplying 1/500 * 1/500 * 1/500.

The odds of getting four 500-year storms in four years would then SEEM astronomical. Using a similar formula, you would arrive at 1 in 62.5 billion!

But that is not necessarily correct because with that calculation you are inferring that the rainfall events are connected. But they actually are not connected. Just because we had a 500-year rainfall event last year, does not mean we may not see another 500- year rainfall event this year.

EVERY year we have a 0.2% chance or 1 in 500 chances of seeing a 500-year flood for a specific location.

This assumes that the odds are no greater in one year than any other year, and that each event is independent of the others.

How do mathematicians compute the probabilities of these rare events? Obviously, it isn’t through observation. The earth is only about 4.5 billion years old. Humans have only walked the earth for about 200,000 years. And reliable rainfall records in this part of the world only go back a little more than a 100 years.

Probabilities for rare events, such as hundred- and five-hundred year storms are based on a branch of statistics called EVA, extreme value analysis. EVA tries to calculate the probabilities of unobserved events by looking at the distribution of observed events.

But all this technical brilliance is based on one particularly flawed assumption that never gets communicated to the public. The assumption is that for the period under examination, nothing changes. Mathematicians even have a word for it: stationarity. It means underlying factors can neither increase, nor decrease.

Duh! Nothing changes in 500 years? In Houston?

Obviously, those folks never rode around for a day in a Ford F350 with a Houston developer.

In 1900, Houston had a population of 44,000 and was the 85th largest city in the U.S.

Today, the Houston region has a population of more than 6.9 million. That’s growth of 157X in a little more than a century. And that’s a lot more concrete than even Bubba and Jim Bob together could spit on in a lifetime.

Diane Cooper, a Kingwood resident with more than 20 years of forecasting experience for the National Weather Service points out a couple other problems with these projections. First, the data is very, very, very thin and rarely updated.

Second, the probabilities are computed for a specific point, not a city, county, region or country. Storms know no geographic boundaries.

In fact, she says, it’s a little bit misleading to say that Houston got hit by three 500-year storms in three years. That’s because any given storm may not have equal intensity over all parts of the city. A storm may have had 500-year intensity on the north side. but only 100-year intensity on the south. Following the same line of logic, but in a different direction, if you expanded the boundaries out to the entire U.S., we might have multiple 500-year storms in one year (each in different places).

Cooper also points out that 500-year storms do not necessarily produce 500-year floods. They are two different beasts.

If the ground is dry, say from a drought, a large percentage of a heavy rain might be absorbed, yielding less than a 500-year flood. Conversely, if the ground is saturated and we get a 100-year rain, get out the oars and inner tubes.

Even though charts like the one above have more uncertainty than a dart player who just downed a fifth of Jack Daniels, they do put big storms in perspective.

By the way, the term “500-year flood” originated in the 1960s when the National Flood Insurance Program was being developed. At the time, people intended it to mean “a storm with a .002% chance of happening in any given year.” However, over the years, the meaning became distorted. Because it had a 1 in 500 chance of occurring each year, insurers started calling it a 500-year storm. People mistook that to mean “the interval between intense storms.”

More on that in a future post and how to calculate the chances of getting hit by a monster storm during the life of your 30-year mortgage. Hint: call your insurance agent now!

Posted May 23, 2018 by Bob Rehak

267 days since Hurricane Harvey

Where did all the sand come from?

Our San Jacinto River is clogged with sand that impedes the flow of water and contributes to flooding. Where did all the sand come from? When? Under what conditions? Are there ways to reduce the volume of sand coming downstream? As the U.S. Army Corps of Engineers prepares to dredge the San Jacinto for the first time, we should ask ourselves these questions.

The river has eight tributaries that affect the Lake Houston Area: Spring Creek, Cypress Creek, Lake Creek and the West Fork on the west; and Peach Creek, Caney Creek, Luce Bayou and the East Fork on the east. All produce sand naturally.

They send sand downstream at different rates at different times, depending on the location of rainfall within the watershed, the volume of flow, the speed of flow, and management of the flood gates at Lake Conroe.

San Jacinto River Watershed Map. Tributaries affecting the Humble/Kingwood area include: Cypress Creek, Spring Creek, Lake Creek, West Fork, Peach Creek, Caney Creek, East Fork, and Luce Bayou.

Other factors include the percentage of sand content in soil and the health of vegetation along stream banks. Vegetation retains and slows runoff, reducing erosion.

The Natural Resources Conservation Service of the USDA produced this soil map of Montgomery County. Blue colors indicate highest percentage of sand; red colors indicate the lowest. Note huge concentrations of sand on Spring Creek and West Fork.

The map above helps us understand why so many sand miners chose to locate along the West Fork – lots of sand. The West Fork is also sparsely populated compared to Spring Creek as you can see in the satellite image below. It shows the sand mines around the Humble/Kingwood area highlighted in red. One is located on Caney Creek (right); the rest are on the West Fork (left).

Satellite image from Google Earth with sand mines around Kingwood outlined in red. Image dated 10/28/2017.

While sand has been coming down the river and streams for thousands of years, rapid sedimentation in the West Fork between Humble and Kingwood didn’t become an issue until the growth of sand mining on the West Fork in the late 1980s.

Notice how most of the areas in red above are filled with natural vegetation in the 1985 image below.

Satellite photo of Kingwood area in 1985 before rapid growth of sand mining. Compare areas in red to previous image.

Today, mines expose approximately 20 square miles of loose sand on the West Fork alone between I-45 and US59.

Aerial photo taken on 9/14/18 of sand mining operation on West Fork.

Dikes around the mines are supposed to keep sand from being discharged into the river. However, Harvey inundated the mines.

Harvey’s floodwaters topped the dikes of sand mines. Image taken 8/30/2017.

An analysis of satellite images before, during and after Harvey shows massive loss of sand from stockpiles within many of these mines.

During floods like Harvey when the SJRA releases water from Lake Conroe, dikes are overtopped and broken. I suspect that sand then comes down the West Fork in tremendous volumes that dwarf Spring Creek’s contribution.

To test this hypothesis, I looked at USGS flow data for both tributaries. I also reviewed all my aerial photos and Google Earth’s historical images.

Under normal conditions, Spring Creek flows at 80 cubic feet per second (cfs) and the West Fork of the San Jacinto at 150 cfs. These are not sufficient flow rates to suspend sediment the size of sand. (For an excellent discussion of sedimentation, see Fundamentals of Sediment Transport at Fondriest.com.)

However, during Harvey, Sring Creek flowed at 78,200 cfs; and the West Fork at 55,000 cfs. Then the San Jacinto River Authority opened the gates at Lake Conroe. That flipped the ratio dramatically. With the flood gates open, Spring Creek still flowed at 78,200 cfs, but the West Fork increased to 130,000 cfs. Flow rates that high can (and did) move houses off their foundations.

Four hundred and fifty aerial photos in the gallery of this web site show a bright, white trail of sand between sand mines and the sand clogging the East and West Forks around Humble and Kingwood. Flood waters swept that sand from a to b. The giant sand deposits at River Grove Park and elsewhere grew exponentially during recent floods.

This tells me that when discussing the origins of the sand, we need to primarily evaluate the river during floods. More water is moving faster under greater pressure. That’s when erosion and deposition happen quickly. That’s when the river overtops and ruptures dikes. And that’s when twenty additional square miles of exposed sand surface on the West Fork make their major contribution to our sediment and flooding problems.

We can’t control sand coming down rivers naturally. However, with better sand mining practices, we may be able to reduce mankind’s contribution to our flooding problem, not to mention the related cleanup costs borne by taxpayers.

In upcoming posts, I will discuss my research into sand mining best practices.

Posted May 22, 2018 by Bob Rehak

266 Days since Hurricane Harvey