Below are two videos taken by Jim Zura of Zura Productions before and after Harvey. Together with other still images, flooding statistics and the Army Corps’ Value Engineering report, they demonstrate how radically Harvey transformed the West Fork. As you review these, keep in mind that the proposed new high-rise development in this area based its engineering on pre-Harvey assumptions.
Zura, a videographer and local drone pilot, shot this first video in 2016. River Grove Park looked pristine. Beyond it, a massive clear cut area surrounds an idyllic little lake. This is where a developer plans to build a high-rise resort around a marina. The drone then rotates to reveal a river without blockages downstream, or in front of the boat docks. In just 18 months, everything would radically change.
River Grove Before Harvey and the Sand
Hurricane Harvey brought with it massive rainfalls that washed sediment downstream, clogging the West Fork. Onshore, they reached up to five feet and stretched 450 feet inland.
Still frame from Jim’s video compared to a shot I took from a helicopter two weeks after Harvey. The angles are slightly different but they show the same location.
It’s called reduced conveyance of the river. The Army Corps documented this in its Value Engineering Study. Here are some shots I took after Harvey from a helicopter. Consider them within the context of the videos above and below. You will understand why River Grove has been near-continuously inundated for a month. I wonder how the owners of luxury high-rise condos would feel about not being able to access their property for that long.
To get a feeling for how much sand was left in the river by Harvey, see how much lined both shores of the West Fork.Sand on both side of the river stretched 450 inland after Harvey. Nearest the river, it reached 5 feet in height through this reach of the West Fork.A giant sand bar 12 feet high and 1500 feet long was deposited in one event: Harvey. It blocked the drainage ditch that empties the western third of Kingwood. The proposed new high-rise development would also depend on this ditch.
I fail to see how the high-rise developer filling in hundreds of additional acres of floodplain with 12-feet of fill could have zero net impact. If every engineering survey ever submitted for a flood plain development were correct, the world would have no flooding problems.
River Grove after the Christmas flood. Water went down briefly then came back up during the next flood in early January. As of today, the soccer fields were still flooded. See the area that compares to the first video at the end of this one.
Posted by Bob Rehak on 1/8/2018
497 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/01/WF-B4AfterHarvey.jpg?fit=1500%2C488&ssl=14881500adminadmin2019-01-07 20:52:122019-01-13 12:33:21Before and After Harvey Images Show Impact of Sediment on West Fork Flooding
Sand Island South of the Kingwood Country Club’s Island Course. I took this picture from a helicopter shortly after Hurricane Harvey. This giant dune virtually blocks the entire West Fork. Experts think it contributes to repeated flooding upstream since Harvey.
After
Keith Jordan, a resident of Kingwood Lake Estates, sent me the pictures below today. They show how quickly Great Lakes Dredge and Dock and the Army Corps are reducing the giant blockage nicknamed “Sand Island” south of Kingwood Country Club. Keith generously consented to let share his pictures with you. He says that much of the island has already been brought down to the water line. It used to jut up 6-10 feet. Still, much dredging remains to reduce the portion below water and restore the conveyance of the West Fork. Progress may look greater than it actually is at the moment because of persistent flooding. As of this posting, the river is still at 46.07 feet according to the USGS gage at US59. That’s about 3.5 feet above normal.
This booster pump keeps sand moving upstream to placement area #2, an old sand mine on Sorters Road south of Kingwood College.
Dredge #2 from Great Lakes Dredge & Dock has been eating away that Sand Island since moving downstream from River Grove Park.
Much of Sand Island is now at the water level.
This wider shot gives you a good feeling for how little is left.
Hopefully, we will get more recent aerial shots from our local drone pilots soon. As the West Fork returns to its normal level, we will see exactly how much of Sand Island remains.
Posted by Bob Rehak on January 6, 2019
496 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/01/IMG_5434.jpg?fit=1280%2C960&ssl=19601280adminadmin2019-01-06 22:07:552019-01-07 06:45:28Sand Island Losing Ground to Army Corps
Guidelines for floodplain development can bewilder even professionals. Overlapping jurisdictions often have different guidelines. And guidelines often change, as Houston’s just did. Houston now manages the 100-year and 500-year floodplains differently. Cities also have building codes that include more requirements.
Site of the proposed new marina and high rise development. Shot from over the West Fork shortly after Harvey. Note sand deposited by Harvey. 25 and 50-story high-rises would be built on the narrow strip between the lake and the Barrington at the top of frame.
Overview
People ARE generally allowed to build and place fill in floodplains. However, they must follow local floodplain guidelines and obtain permits that restrict what they can do. They must also submit environmental surveys, mitigate wetlands, and provide hydrologic and hydraulic studies. In Houston, they may move earth from one location to another within a floodplain, but not add to the total volume. The general rule of thumb: zero negative impact on the conveyance of the river.
If a development destroys wetlands, wetland credits must be purchased from a mitigation bank. Mitigation banks place conservation easements on some of our most valuable wetlands. By helping to finance conservation of those areas, destruction of less valuable wetlands elsewhere may be permitted. Generally but not always, the mitigation credits must be within the same watershed. However, this is not always the case. Extenuating circumstances may exist.
KSA once considered placing East End Park in a mitigation bank as a way to help finance its long range parks plan. The conservation easement would ensure that the character of the park never changed. And the money raised would have provided needed improvements to other parks at no cost to residents.
Federal Guidelines and How They Relate to Local
FEMA establishes minimum standards for a community to enroll in the National Flood Insurance Program (NFIP). By enrolling and administering floodplain regulations, it allows their residents the opportunity to purchase Flood Insurance through the NFIP. You must at least build at FEMA’s base flood elevation (BFE). But communities can and do set higher standards. And each may have different guidelines.
Engineers and regulators often talk about “freeboard factors.” Freeboard, a nautical term, means “the height of a ships side between the waterline and the deck.” In a flooding context, freeboard means minimum elevation above the BFE. You often see it described as “BFE + 1 ft.” Or 2 feet. Or X feet. Think of it as a safety margin. Any freeboard above the BFE is considered a local community’s higher standard.
To provide a context, below are links to some of the floodplain management orders/ordinances.
Note Chapters 9 and 13. They changed on September 1, 2018. Changes address building code issues for FEMA X zones. Zone X includes the 500 year flood plain. Many such areas flooded during Harvey.
If a development affects a major waterway like the San Jacinto River, its wetlands, its flow, or endangered wildlife, the Army Corps will also review studies submitted as part of the permitting process. They would look at applications from the point of view of the EPA and Clean Water Act, especially Section 404.Section 404 of the Clean Water Act (CWA) establishes a program to regulate the discharge of dredged or fill material into waters of the United States, including wetlands. … For most discharges that will have only minimal adverse effects, a general permit may be suitable. This is the major focus of the permitting process now underway for the high-rise development in Kingwood.
TCEQ
The Clean Water Act also contains a section 401. It specifically focuses on how States and Tribes can use their water quality standards in Section 401 certifications to protect wetlands. States and Tribes can review and approve, condition, or deny any Federal permits or licenses that may result in a discharge to waters of United States within their borders, including wetlands. States and Tribes make their decisions to deny, certify, or condition permits or licenses primarily by ensuring the activity will comply with applicable water quality standards. In addition, States and Tribes look at whether the activity will violate effluent limitations, new source performance standards, toxic pollutants restrictions and other water resource requirements of State or Tribal law.
Jurisdictional Divides
The Houston ordinance only applies to Houston’s jurisdiction. Houston does not influence neighbors and cannot control or force their policies on other jurisdictions. That is important since Kingwood is surrounded by Humble, unincorporated Harris County (Atascocita and Huffman), and unincorporated Montgomery County.
The Key
Understand that if a developer/individual meets the requirements identified in the floodplain ordinance(s), they can develop in the floodplain (including the floodway). Floodplain administrators must follow the law. However, they try to discourage dangerous floodplain development by “working to rule.” By strictly following all rules with no wiggle room, floodplain administrators can drag permitting processes out. A knowledgeable floodplain administrator can find problems with plans, surveys, and engineering reports for years. By requesting revisions, they can make life so difficult for applicants that it affects the economics of their developments. Eventually they may decide that a project falls into that great black box called “too hard to do,” and walk away.
Words of Wisdom
A regulator told me today that the more people who protest a permit, the harder they are to ignore.
If you have concerns about the high rise development in Kingwood, make sure you register them with the Army Corps (which is currently reviewing the permitting from a CWA 404 perspective). The deadline: January 29.
Comments and requests for additional information should reference USACE file number, SWG-2016-00384, and should be submitted to:
Evaluation Branch, North Unit
Regulatory Division, CESWG-RD-E
U.S. Army Corps of Engineers
P.O. Box 1229
Galveston, Texas 77553-1229
409-766-3869 Phone
409-766-6301 Fax
swg_public_notice@usace.army.mil
Posted By Bob Rehak on January 9, 2019
498 Days Since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/03/Harvey-SanJac_179-e1546828712317.jpg?fit=1500%2C1000&ssl=110001500adminadmin2019-01-06 21:33:032019-01-13 12:35:07Guide to Lake Houston Area Floodplain Regulations
If you witness illegal discharges, dumping, or mining, following these guidelines will ensure the Texas Commission on Environmental Quality (TCEQ) can act on evidence you provide. Make sure you follow proper procedures.
After Harvey, fresh sand deposits several feet thick and foul water lined the shores of the west fork of the San Jacinto adjacent to Kingwood.
If you want TCEQ to use your information in an enforcement case, you cannot remain anonymous.
You must complete a notarized affidavit. Your contact information will be confidential. But understand that you must be willing to testify in any formal enforcement hearing.
You may not enter property of another person to document a violation. No trespass.
Follow the Commission’s procedures and protocols outlined in the link above.
If the Commission initiates an investigation, you must sign affidavits authenticating the information you provided.
You must confirm that you followed TCEQ protocols and procedures.
If the case proceeds to a formal hearing or trial, you will be required to testify. You must explain information you provided, and you may be cross-examined by the defendant’s attorney. This could include questions regarding your testimony and motives.
Given all the different types of complaints and evidence people submit, procedures can get quite complex. For instance, if you submit water samples, the TCEQ has specific requirements for testing and chain of custody.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/03/Harvey-SanJac_3-e1546743219721.jpg?fit=1500%2C1000&ssl=110001500adminadmin2019-01-05 20:29:252019-01-05 20:55:04How to Submit Evidence that Gets Results from the TCEQ
Good news: The Emergency West Fork Dredging Project is still active. The government allocated funds for the project before the shutdown. Also, because FEMA designated it an emergency, it enjoys preferred status. Dredges are still dredging.
Bad news: Every other Lake Houston area flood mitigation project that depends on federal dollars is on hold.
Watershed study? 10 months and still waiting for approval.
Additional gates for Lake Houston? Hit the pause button.
More upstream detention. Deep freeze.
Additional dredging? Why rush it?
The Really Bad News
I’d say that’s the end of the story, but it’s not. Tonight the Associated Press reports that President Trump warns the shutdown could continue for months or years. Even considering the obvious hyperbole, I shudder to think of employees’ reactions. At a certain point, people put families and futures in front of jobs that pay zero. Maybe Trump could hold out for years. But a GS-7 with a bachelor’s degree and student loans to pay off? Someone making $35K per year?
The reason most people take a pay cut to go into government service is because it’s a steady gig. But yank that paycheck out from under them. Woooooosh! That’s the sound of talent and institutional knowledge creating a vacuum as it sprints out the door.
Rebraining Projects
A prolonged government shutdown will turn the Mo down Low. Lose momentum and you have to spend more energy to regain it. You lose time. You lose money. You lose talent. And when it’s over, you have to rebrain projects. Recruitment. Training. Getting people back up to speed. Clearing out backlogs…that could really last years.
Sweating Details and Bullets
So while the mouth bar project is on hold, dredging behind the mouth bar continues. Officials hoped they could save $18 million in demobilization and remobilization fees by having the mouth bar project ready to start when the Emergency Project finished. But that window is rapidly narrowing. Back in October, when we thought we had six months to work out details, everyone felt comfy and confident. Now with three months left, officials are sweating the details while residents sweat bullets. Here’s why.
Problems Likely to Migrate Downstream
As I discussed in yesterday’s post, River Grove Park has experienced greater-than-usual flooding. Crests usually experienced every other year now happen once every other month. The river has crested over 50 feet six times in 11 months. That’s likely due to the backwater effect created by “Sand Island” (as dredgers have named it). Sand Island virtually blocks off the river creating a backwater effect. See its location relative to River Grove below.
The Army Corps has nicknamed the giant blockage immediately downstream from River Grove Park “Sand Island.”
The next picture shows how this massive dune virtually blocks the entire West Fork. I took the picture two weeks after Harvey. During floods, when water moves quickly, Sand Island has created a ten-foot difference between water upstream and downstream.
Sand Island causes higher-than-normal floods at greater -than -normal frequencies because of backwater effects.
Great Lakes Dredge and Dock, the Corps’ prime contractor on this job has finished dredging through the side bar at River Grove . Now they are attacking Sand Island (see below).
The focus of dredging has moved from the side bar at River Grove to Sand Island. Once removed, the flooding problems at River Grove will likely migrate downstream.
As they remove this blockage, downstream residents in Atascocita Point have reported water rising higher in their yards during floods. Once dredgers completely remove Sand Island, flooding problems will likely migrate downstream to the next major blockage, the mouth bar.
The mouth bar virtually blocks the West Fork where it enters Lake Houston. It stretches from Kings Point to Atascocita Point, but is not within the scope of the current dredging project. Expansion of the scope has been halted by the government shutdown.
However, there’s a big difference between Sand Island and the Mouth Bar.
Parks, vacant land, and golf courses surround Sand Island.
People, kids and homes surround the Mouth Bar.
Let’s pray that the government shutdown ends quickly. In this area, government can really make a huge and important difference – immediately.
Posted by Bob Rehak on 1/5/2019
494 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/01/Locator.jpg?fit=1500%2C1000&ssl=110001500adminadmin2019-01-05 03:25:172019-01-06 12:24:47How Government Shutdown Affects All Lake Houston Area Flood Mitigation Projects
Three months after supposedly reaching an agreement in principle to remove the mouth bar, FEMA, the Army Corps, the State and City still have no agreement in writing. From Day 1 of negotiations, FEMA and the Corps have consistently said they can’t address pre-Harvey conditions. I’m beginning to believe them. How did we reach this impasse and how can we move forward?
FEMA’s Dilemma
The Stafford Act (FEMA’s enabling legislation) prohibits FEMA from funding repairs not directly related to Harvey. But, because the City conducted no surveys after the Memorial or Tax Day Floods, it cannot prove how much came from Harvey. Yet it has asked FEMA and the Corps to remove the entire mouth bar.
The City’s Dilemma
The City of Houston has done little to maintain Lake Houston, especially the West Fork of the San Jacinto near Kingwood. Lack of regular surveys and maintenance dredging make city officials look like they’re trying to get others to clean up their mess.
Historical Perspective
Decades ago, after the 1994 flood, the City hired Brown & Root to study sedimentation in the lake, which includes about 13 miles of the East and West Forks of the San Jacinto. Engineers recommended surveying the river after every major storm and dredging when necessary to reduce the risk of flooding. They even pinpointed where sediment would likely build up and pointed out that the West Fork was capturing 42% of all the sediment coming into the lake (see page 9). However, before Harvey, the City never dredged and rarely conducted surveys – decisions that haunt us today.
The mouth bar. Sand, in part from the mines, has almost totally blocked the West Fork where it meets Lake Houston. Unofficial before/after measurements show that as much as ten feet was deposited in this area during Harvey (five below water/five above).
Sedimentation: Danger that Can No Longer Be Ignored
One insidious aspect of sedimentation is its invisibility. Like gunk in pipes, you can’t see it – until water backs up and floods your home. That’s exactly what happened to thousands of homes during Harvey. The problem which had slowly built up for years, went from sub-acute to critical almost overnight because of the massive volume of sediment deposited during Harvey.
That brings us to our present impasse.
No News is Bad News
The City, FEMA, the Army Corps and the State have argued about this for at least six months. We thought they reached agreement in principle to remove the mouth bar three months ago. But still no official announcements have been made. Sadly, it didn’t have to come to this:
If only the City had followed the advice of the experts it hired…
If only the City had maintained its property…
If only the City could document how much Harvey contributed to the blockage…
If only the City had acted years ago to limit sand mining in the floodway of the river…
…we could have been working on the mouth bar already. Instead…
Problem Becoming Demonstrably Worse
In the 80 years since we started keeping records on the West Fork at US59, the river has crested over 50 feet 40 times – once every other year. But in the last 11 months, floods have reached that height SIX times – more than once every other month. We topped 50 feet in the latest flood just minutes ago. All resulted from relatively minor rains. This sudden surge in frequency did not result from global warming.
Is it all a statistical fluke? Wetter than usual weather? El Niño? Upstream development? Perhaps some of each. But one would have to be blind to dismiss the sediment buildup in the river. A delta is marching steadily downstream, creating blockages that back water up.
The West Fork just before Kingwood’s annexation in 1996 and after Harvey. Comparison shows advancing sediment buildups blocking the river.
The High Cost of Ignoring Expert Advice and Routine Maintenance
Harvey brought the high cost of ignoring expert advice and routine maintenance into sharp focus. The lack of a survey that could have been conducted in a few days is costing the City months of delays and potentially tens of millions of dollars in State and Federal assistance. This exposes hundreds of thousands of residents to needless flood risk and undermines property values.
What Needs to Happen
All of this underscores the need to budget for and maintain one’s own property. Drainage fees, which we just put a lock box around, should easily handle the City’s portion of dredging projects and surveys.
How do we break this impasse?
FEMA and the Corps need to restore the conveyance of the river that existed before Harvey. Estimate it using available evidence like aerial photos and satellite images. We’ll never have an exact figure. So quit using that as an excuse to put hundreds of thousands of people at risk. Let’s get started with dredging what we can. Legally.
In return, the City could commit to annual river surveys that document the status of the river before each hurricane season.
I’m not a mediator and I’m not the Mayor, but that sounds like a fair compromise that can protect residents as well as officials on both sides of this negotiation.
Floods don’t happen as often as police or fire emergencies, but when they do, they affect hundreds of thousands of people in ways that can be just as life altering. This is a public safety issue. Let’s go. Reach an agreement, please!
These are my opinions on matters of public policy, protected by the First Amendment of the U.S. Constitution and the Anti-SLAPP statute of the Great State of Texas.
Posted by Bob Rehak on January 4, 2019
493 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/01/SideBySide.jpg?fit=1440%2C590&ssl=15901440adminadmin2019-01-04 00:14:212019-01-04 09:18:39Why the City Needs Regular River Surveys and Maintenance Dredging
Last night after posting the third flash flood warning in less than a month, several flood-weary people on FaceBook flashed back to Harvey. They questioned why the SJRA wasn’t releasing water in advance of the storm. I quickly went to SJRA.net and looked at their dashboard. They WERE releasing water. The discussion then morphed into another SJRA bloodletting, borne of fear and frustration over a month of near-continuous flood risk and a year and a half of expensive flood repairs.
I’m not here to defend the SJRA. But I suspected perception and reality were currently out of sync. So I emailed a reader’s comments to Jace Houston, general manager of the SJRA, and asked what they were doing to address his concerns.
Update from Jace Houston of SJRA on Recent Releases
Here is the response I got today. I’m reprinting it word for word.
“As you know, there’s a big information gap between what we do during storm events and what the public perceives. We’re working on some significant items to begin closing that gap.”
“We have an information piece that will go out this afternoon regarding the current rainfall event, but I thought I would mention a couple of items to you just in case you get more inquiries.”
“We’ve been releasing water non-stop since the December 7th rainfall. It takes quite a while to safely lower the lake after its risen a couple of feet above normal level. Obviously the level jumped back up from the Christmas rainfall. Releases went back up to around 7000 cfs, and we’re still at over 3000 cfs. Rainfall has been in the forecast pretty much constantly the last 30 days, so we’re in the mode of trying to safely move it out of the lake before the next storm hits.”
“The forecast for this event is not too bad. Approximately two to three inches across our watershed. We’re only a few inches over 201’, so we should be able to manage this one similarly to the Christmas event.”
Jeff Lindner of Harris County Flood Control issued this update re: current rains at 7 p.m. tonight:
“A band of heavy rainfall with rainfall rates of 1.0-1.5 inches per hour is moving NNE over much of Harris County currently extending along the US 59 corridor. HCFCD gages show rainfall amounts of .75-1.5 inches with this band in an hour or less and this will likely result in some street flooding. Rises on area watersheds are likely, but creeks and bayous will be able to handle this round of rainfall.”
“Additional activity to the SW will likely move into the county over the next few hours.”
Hope that helps! Stay tuned to the National Weather Service, NOAA or your favorite source of weather information.
Here are the latest predictions from NOAA for the area around US59 and rainfall in the last 24 hours for Harris County.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/01/hmmt2_hg.png?fit=600%2C465&ssl=1465600adminadmin2019-01-02 21:13:272019-01-02 21:13:34SJRA Has Released Water Continuously since December 7
The developer of a proposed new high-rise resort in Kingwood plans to develop the marina portion in an area that was once the riverbed of the San Jacinto west fork.
Aerial photos taken in 1943 clearly show the outline of an old meander about .4 miles north of the current riverbed.
1943 aerial photo. Note feint outline of old riverbed above the current river.
Google Earth lets users trace a path and then save it, like I have with this orange line.
Creating an outline of the path allows you to scroll forward in time within Google Earth (see image below).
Here is the same path superimposed over current conditions.
Plans call for marina high rises along orange path just north of lake below eastern edge of Barrington.The Marina would be developed in the old river bed of the San Jacinto.
Photo of proposed marina site next to River Grove Park. The giant sand bar in the foreground of this photo taken after Harvey has mostly been dredged by the Army Corps. However, it’s appearance almost overnight during Harvey contributed to the flooding of 650 homes above the drainage ditch (center left). Future development in this floodplain would likely make flooding worse.
Dangers of Building in Old Stream and Riverbeds
During major floods, water often follows these old streams and riverbeds. Many neighborhoods in Houston discovered this danger during Harvey. Former Harris County Judge Ed Emmett often questioned the wisdom of such developments because of their susceptibility to flooding – even after mitigation.
Here are two examples that show such developments encroaching on waterways and separating them from their floodplains. In the first example, the waterway was obliterated. In the second, White Oak Bayou, the waterway still exists. However, the flood plain has been developed. Despite mitigation efforts during development, the neighborhoods around White Oak Bayou have suffered severe and repeated flooding.
Why Do We Continue to Develop Flood Plains?
This brochure, Why We Continue to Develop Floodplains: Examining the Disincentives for Conservation in Federal Policy, is a must-read for anyone who wants to understand the financial logic behind developments like this one. A group called Earth Economics developed it. Zachary Christin, Project Director for Earth Economics, and Michael Kline, from the Vermont Department of Environmental Conservation, authored it with support from the Kresge Foundation. This report investigates whether current federal policy is structured to prevent future flood damage or if incentives lead to further floodplain development.
The basic premise may rub many Texans the wrong way, but you should still read it. “Flood risk management,” the authors argue, “seeks to enable communities to live nearby by controlling rivers with levee systems and other structures. This false sense of protection places families and infrastructure at risk in a climate that is changing beyond our capacity to maintain protections against its effects. Rather than attempting to control our country’s powerful rivers, we should instead control how and where we allow human activities.”
Confining streams, they argue, merely shifts flood risk downstream. The authors explore the benefits and the natural protective qualities of healthy, functional floodplains. They then discuss the causes of floodplain destruction and investigate the policies that further incentivize their development. Finally, they outline paths forward to create new floodplain policy. You may disagree with the premise. But it contains many powerful observations and statistics.
As always, these represent my opinions on matters of public policy. They are protected by the First Amendment of the U.S. Constitution and the Anti-SLAPP statute of the Great State of Texas.
Posted by Bob Rehak on January 2, 2019
491 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/01/AncientMeander.jpg?fit=1500%2C1023&ssl=110231500adminadmin2019-01-02 19:38:332019-01-13 12:36:05Developer Plans to Build High-Rise Resort in Old Riverbed
Flash flooding and flooding will be possible Wednesday into Thursday. A band of heavy rainfall may form Wednesday morning from College Station to Crockett and heavy rainfall may continue to occur through the day. Gulf moisture will also move into the area and cause additional rainfall mainly east of I-45.
Southeast Texas has already had rainfall the last seven days which will cause any additional rainfall to runoff. Isolated thunderstorms may cause brief heavy rainfall of 1 inch an hour. Overall areas in the watch may get 2 to 3 inches of rainfall with isolated bands of 4 inches.
Potential Flood Impacts
In urban areas, street flooding and flooding of underpasses and typical low lying areas can be be expected. Bayous and creeks may have rapid rises and could reach out of banks. Rural low lying areas, low water crossings and poor drainage areas may flood. Rises on area rivers can be expected and this could extend river flooding that is on going.
PRECAUTIONARY/PREPAREDNESS ACTIONS
A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.
Additional Guidance from Harris County Flood Control
Jeff Lindner, Harris County Flood Control’s meteorologist added this:
Widespread rainfall…some heavy…will lead to rises on area watersheds and potentially some flooding of creeks and rivers.
Upper level storm system is digging into the SW US and will impact the state for the next 24-36 hours.
As moisture increases from the SSW this evening, light rain and showers will develop and spread NNE into the area. A secondary front from roughly Lake Livingston to Columbus will likely remain stationary and be the focus for rainfall production tonight into early Wednesday in that region. Expect numerous showers and thunderstorms to develop by midday along the coast and inland south of the stalled inland front…this rainfall will likely become heavier in nature and slightly more convective with potentially higher rainfall rates. Upper level system will move across the area early Thursday with rains continuing before dry WNW winds sweep across the area in the afternoon ending rainfall.
Rainfall Amounts
Widespread rainfall of 2-3 inches looks likely over much of the area with isolated totals of 4-5 inches. Some fairly decent agreement in the models today with respect to two rainfall maximums over the area…the first over our NW/N counties tonight in Wednesday and then a second Wednesday afternoon into Thursday morning from Houston ENE toward Liberty and then NE toward Lake Livingston. WPC has expended the slight risk of excessive rainfall exceeding flash flood guidance to include a larger part of SE TX. Think maximum hourly rainfall rates will be on the order of .5 to 1.25 inches which most urban areas will be able to handle. Overall fairly long duration of rainfall over a fairly large area will lead to significant amounts of run-off especially into area river systems as well as the creeks in northern Harris County.
Flash Flood Guidance
Flash Flood Guidance for the area is between 3.0-4.4 inches for 6-hrs which seems high and a review of soil saturation levels via the NASA SPORT webpage shows saturation levels of 65-70% over much of the area…or you can walk in the yard and quickly tell that the ground is still very wet from the rainfall on Sunday. Think much of what falls is going to run-off given how wet the ground is and widespread amounts of dormant vegetation.
Several watersheds are still high from the rainfall last Thursday and rainfall of this magnitude will likely result in renewed rises on nearly all watersheds. Main concern will be the Trinity and San Jacinto basins, along with the Navasota and Brazos. In Harris County, significant rises on Spring, Cypress, Little Cypress, Willow, Cedar, and the creeks that feed into Addicks and Barker Reservoirs are likely. Will also include lower Greens (east of US 59) and Halls, Hunting. Some of these watersheds may rise to levels that would impact low lying areas and roadways near the creek or bayou.
Flooding Probable on East and West Forks
Flooding on both the East and West Forks of the San Jacinto River (low lands and streets) certainly looks probable. At this time the threat for significant creek and bayou flooding as well as any flooding of structures is low.
Current thinking is that watersheds will see similar responses to last Thursday morning…although a few may see higher levels since they will be starting at higher current flows versus last Thursday.
Think hourly rainfall rates will be low enough to prevent widespread street flooding, but street flooding in areas of poor drainage and in rural areas where roadside ditches or small creeks spill onto the roadway will be possible.
Posted by Bob Rehak on 1/1/2019
480 Days Since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/01/Balcom_25.jpg?fit=1500%2C1000&ssl=110001500adminadmin2019-01-01 18:30:232019-01-01 18:30:29Flash Flood Watch Issued from 6 a.m. Wednesday to Noon Thursday
Yesterday, the area where a developer proposes a new high-rise development flooded for the fifth time this year. This underscores the need for remediation before any permitting.
It wasn’t an especially heavy rain last week. Kingwood received about 2.5 inches. Areas upstream averaged 3 to 4 inches. Yet the West Fork came out of its banks and flooded River Grove Park for the fifth time this year (February 26, March 28/29, July 4, December 7/8, December 27). The USGS Gage at US59 showed that the flood crested at about midnight. The crest reached almost 50 feet at US59.
The West Fork at US 59 crested at almost 50 feet from the most recent rains. In the days preceding, SJRA released 5-7,000 cfs from Lake Conroe.
Jim Zura of Zura Productions took his drone to River Grove during the last light before the overnight crest. The video shows that although the road was still useable, many of the park’s popular amenities were not. The playground, soccer fields, boat ramp and boardwalk all flooded.
Earlier this year, the US Army Corps of Engineers found that excessive sedimentation in the river contributed to excessive flooding. The frequency of these floods supports that conclusion. The Corps began dredging in late September to remove sediment, but has completed only about 20% of the project so far. Downstream blockages remain. And the biggest – at the mouth of the West Fork – is not even within the scope of the current dredging project.
The end of Zura’s video shows the soccer fields and adjoining property, including a small lake in the floodway. This flood gives us a glimpse of how a minor rain would affect the proposed high-rise development there.
Watch all the way to the end!
The frequency of these floods underscores the need to consider the implications of permitting such a major development – especially when officials know the engineering is based on obsolete data and flood maps that in no way reflect current realities.
Until remediation efforts are complete, officials should postpone consideration of the permit. Remediation efforts include:
Dredging the West Fork all the way from US59 to Lake Houston
Creating additional upstream detention
Adding flood gates to Lake Houston
Restoring the conveyance of local drainage ditches and streams.
Rainfalls of the magnitude that caused these five floods should happen about once every 2 years according to Harris County Flood Control. This year they happened five times: 10X greater than expected. A review of peak crest data since 1929 roughly confirms these expectations. In the 80 year since then, the river crested over 50 feet only 40 times.
A review of the same data shows that the river has crested over 57 feet 9 times in the last 80 years and six times since 1994.
I believe excessive sedimentation played a role in this frequency increase. Instead of flooding every other year like this, we’re flooding almost every other month. That’s significant enough to put the brakes on development in the floodway, at least until we understand the extent of the problems and can fix them.
These are my opinions on matters of public policy. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statutes of the Great State of Texas.
Posted by Bob Rehak on December 31, 2018
489 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/12/Zura2.jpg?fit=1500%2C843&ssl=18431500adminadmin2018-12-30 13:08:172019-01-26 08:03:54Drone Video Underscores Dangers of Development without Remediation
