The recent drought has reduced the rate of erosion under the Tree Lane/Bens Branch Bridge for now. But with wetter weather expected, we need to accelerate the repair effort. Recent pictures show the desperate need for repairs to the bridge. It’s next to Bear Branch Elementary School where more than 600 students attend grades K-5.
Power of Moving Water
The current state of this bridge and the area around it is a testament to the power of moving water … more than engineers designed the bridge to handle.
Water jetting under the bridge during storms has ripped away great slabs of concrete, eroded side walls, and partially blocked a storm drain outfall.
Condition of Tree Lane Bridge over Bens Branchon 11/24/23
It has also eroded the channel. Rip rap has done little to halt the erosion.
11/24/23. Condition of Tree Lane Bridge over Bens Branch.
Downcutting has exposed utility lines. And stormwater has carried chunks of concrete downstream like toothpicks.
11/24/23. Bens Branch downstream of Tree Lane Bridge.
Before Hurricane Harvey, the tree canopy in this area was so dense, one could barely see Bens Branch from the air. Now, there’s a gaping hole in the landscape caused by the “jetting.”
11/24/23. Downstream erosion of greenbelt caused by jetting water from under bridge.
As more and more water builds up behind the bridge during storms, it causes water to shoot under the bridge with greater pressure and accelerate erosion.
One can’t help but wonder whether the random and cumulative impact of several large storms caused this damage. Whether insufficiently mitigated upstream development helped nature along. Or whether the bridge simply reached the end of its normal life.
But a prolonged, intense drought last summer put an end to the acceleration. A close comparison of recent photos with those taken six months ago shows that the bridge now looks much like it did last June.
When Will Bridge Be Fixed?
I have learned that both the City of Houston and Harris County Flood Control District (HCFCD) are studying the bridge. In August, the City even allocated money to fix it. However, HCFCD worried about the impact to its Bens Branch channel. The two entities are now trying to reach a mutually agreeable solution.
Having lived near here for 40 years, one thing is clear to me. We can’t count on drought to prevent more erosion forever.
During El Niño years (like now), much of Texas is cooler and wetter than average. Northern storms generally track farther south, producing more clouds, rain and severe weather, according to the NWS.
Perhaps we’ll get some good news on Tree Lane bridge repairs or replacement by Christmas. I’ll let you know when we get the engineering report.
Posted by Bob Rehak on 11/28/24
2282 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/11/20231124-DJI_0174.jpg?fit=1100%2C733&ssl=17331100adminadmin2023-11-28 07:16:142023-11-28 07:16:15Tree Lane Bridge over Bens Branch Still Standing
Harris County Flood Control, SJRA, and the Cities of Humble and Houston using funding provided in part by the Texas Water Development Board are searching for sediment solutions in the Upper San Jacinto River Basin. Their major scientific study includes all or parts of seven counties: Harris, Montgomery, Waller, Grimes, Walker, San Jacinto and Liberty – all land draining into Lake Houston.
From Technical Memorandum 1 of the Upper San Jacinto River Basin Regional Sedimentation Study.
The high-level goal: to better manage sediment in the river basin. Sediment reduces both floodway conveyance and the storage capacity of Lake Houston. Both contribute to the frequency and severity of flooding.
Among other things, the study partners hope to prioritize sediment hot spots so they can develop sediment solutions and recommendations.
I hope they look at Colony Ridge. It exemplifies a major hot spot and points the way to an obvious sediment solution – better enforcement of existing regulations.
Scope and Status of Sediment Study
The study is now about half complete. With much of the fieldwork complete, the partners will next focus on modeling, hotspot identification, area prioritization and sediment solutions, according to Matt Barrett, Water Resources and Flood Management Division Manager atSJRA.
To date, the study has examined a variety of factors:
Sediment Solutions Must Address Development Practices
Erosion occurs naturally. But poor development practices can accelerate the rate of erosion unnaturally.
Regulations in Liberty County call for backslope interceptor swales to prevent sheet flow over the sides of ditches. I have yet to see one such system anywhere in the 30+ square miles of Colony Ridge. What you typically see is this.
All that sediment washes downstream where it reduces the carrying capacity of rivers and the storage capacity of Lake Houston.
Liberty County regulations also call for planting grass on the side slopes of ditches and detention basins. The grass reduces erosion, too. But you don’t see much grass on those side slopes either.
Compare the ditch above with the ditch below in Harris County to see how grass and backslope interceptor swales can reduce erosion.
Small swales behind main slopes capture sheet flow heading toward the ditch. Pipes then take runoff to the bottom of ditch, thus reducing erosion on side slopes.
Here’s Colony Ridge again.
Three-mile-long Colony Ridge drainage ditch has no grass or backslope interceptor swales.
Address the Elephant in the Room Before the Next Disaster
Ironically, both Liberty and Harris County have almost identical regulations for erosion control. Harris County enforces them; Liberty County doesn’t.
Enforcement of development regulations is the elephant in the room.
So, as the SJRA and its partners search for sediment solutions, here’s one simple recommendation. Enforce regulations already on the books.
Colony Ridge and other developments that skirt regulations represent a disaster waiting to happen. Unfortunately, it will probably take a disaster, such as Harvey, to cause leaders to take action. But by then, it will be too late.
Posted by Bob Rehak on 10/20/23
2242 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/10/20231006-RJR_6038-1.jpg?fit=1100%2C733&ssl=17331100adminadmin2023-10-20 14:08:222023-10-20 17:39:42Search For Sediment Solutions Should Lead Straight to Colony Ridge
Colony Ridge, the world’s largest trailer park, fails to meet Liberty County regulations for the construction of stormwater detention basins and ditches. The development’s basins and ditches routinely lack erosion controls such as grass and backslope interceptor swales. The resulting erosion can reduce the conveyance of streams, increase flood risk and threaten property both inside the development and downstream. The failure to follow those regulations imposes a hidden tax on residents of Liberty and surrounding counties.
Pages 152 and 153 of the regulations also require backslope drain systems to “intercept sheet flow which otherwise would flow over the banks of drainage channels leading to erosion of the side slopes.” Swales behind the edges of basins and channels trap stormwater. Pipes then carry it to the bottom of the ditch or basin so that it won’t erode side slopes.
What Ditches/Detention Basins Should Look Like
The photo below shows a Harris County ditch with grass on the side slopes and pipes that lead from backslope swales to the bottom of the channel. Note how they reduce erosion and sedimentation.
Harris County ditch which follows regulations similar to Liberty County’s. Compare the Colony Ridge ditches below.
Compare Requirements to Photos
I took the pictures below on 8/12/23 from a helicopter while flying over Colony Ridge in Liberty County. Note the lack of grass and interceptor inlets/outlets. Also note the severe erosion that results.
Note severe erosion on banks of pond. Also note lack of backslope swales, inlets, and outlets in base of pond.No backslope interceptor system. No grass.No backslope interceptor system. No grass.No backslope interceptor system. No grasson sides of ditch.Ditto.Ditto
In some cases, the ditches and detention basins don’t even have perimeter maintenance roads and the erosion is cutting into people’s back yards.
Colony Ridge resident losing back of property due to ditch erosion.
The Largest Development Few Know About
Colony Ridge is large and growing rapidly. The satellite image below shows how it has virtually doubled in size within the last two years as it has grown from left to right and bottom to top. The large area in the lower left began developing around 2011. Those lines that look like hashmarks are thousands of mobile homes.
This satellite image taken in July 2023 does not even show the development’s current extent. Much of the area in the upper right below the clouds was cleared since then.See below.Portion of Colony Ridge in upper right of satellite photo has now been cleared.
Colony Ridge already comprises more than 30 square miles. That makes it approximately one third the size of the area inside Houston’s 610 loop.
Mostly mobile homes and rivers of mud as far as the eye can see.
Erosion a Major Issue
Colony Ridge drains into three watersheds: the East Fork San Jacinto, Luce Bayou and Tarkington Bayou. And all of them drain into Lake Houston. That will make erosion from Colony Ridge Harris and Liberty County’s problem forever.
“Erosion and sedimentation can have very serious effects on storm water drainage.”
“Erosion can cause slope failures, increase roughness coefficients, and generally reduce the efficiency of drainage channels. However, sediment deposition can clog drainage culverts and reduce the available conveyance in open channels.”
“Erosion can significantly reduce the maintainability of drainage facilities and increase the cost of maintenance by increasing the frequency with which repairs are required.”
LJA engineering wrote a letter to the Liberty County Engineer that underscores the need to plan ahead as the county transitions from rural to urban. “While limited regulation of development in a rural area may not significantly impact drainage issues, Liberty County is now challenged with explosive population growth and a particularly high percentage of socially vulnerable residents…” said the letter.
Hidden Cost to Downstream Residents
Most people in Harris County don’t even know that Colony Ridge exists. Yet the drainage practices there affect dredging costs downstream. The City of Houston, Harris County and Army Corps spent almost a quarter billion dollars dredging the headwaters of Lake Houston between Harvey and mid-2021.
Clearly, not all of that sediment came from Colony Ridge. However, the development practices in Colony Ridge and other developments like it will set the pattern for the future.
Developments are virtually impossible to change after people start building next to undersized basins and ditches that erode more with every substantial rain.
What You See Makes You Question What You Don’t See
Substandard construction practices make you wonder about engineering practices. Did Colony Ridge engineers produce reliable, accurate estimates of drainage needs? Are those ditches and detention basins sized properly? Will they hold enough runoff to protect residents?
Probably not. Even assuming engineers and contractors did their jobs properly (a big assumption), Liberty County still defines a 100 year/24 hour rainfall as 13.5 inches (see page 108), a rate associated with pre-Atlas 14 days.
Atlas 14 catalogs the current national precipitation frequency standards for every community in the U.S.
However, the phrase “Atlas 14” appears nowhere in the 2019 Liberty County Subdivision and Development Regulations.
But NOAA now defines a 100 year/24 hour rainfall for nearby Cleveland, TX, as 17.1 inches – a 27% increase above the current Liberty County standard. So in a hundred-year rainfall, everything you see in Colony Ridge will be 27% short of capacity. Few people likely understand this.
Consider also that NOAA is already working on replacing Atlas 14 with Atlas 15!
Posted by Bob Rehak on 8/16/23
2178 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/08/20230812-RJR_5768-e1692197968560.jpg?fit=1100%2C733&ssl=17331100adminadmin2023-08-16 11:46:552023-08-16 23:01:40Colony Ridge Stormwater Detention Basins, Ditches Fail to Meet Liberty County Standards
Concrete reinforcements under and on both sides of the bridge have collapsed from undercutting, erosion and jetting.
The stream has downcut, exposing pipelines.
Jetting has carved out a cavernous area south of the bridge.
Erosion has reached within a few feet of a utility corridor.
Storm sewer outfalls have been exposed, undercut and punctured by massive slabs of displaced concrete.
Bridge supports, once protected by sidewalls, have been exposed to more erosion.
Pictures Taken on 6/12/23 Show Extent of Damage
The bridge will probably not collapse in the next big rain. However, the cumulative damage to all these components underscores the need for urgent repair. It also underscores the need for mitigation to reduce the jetting that caused the damage.
Looking NE at downstream, eastern side of Tree Lane bridgeWider shot from same position reveals two exposed pipelines.Looking upstream under Tree Lane Bridge. Note how downcutting threatens western (left) wall also.Giant slabs of concrete have destroyed outfall.Erosion downstream of the Tree Lane bridge now is within approximately ten feet of a utility corridor.
Damage Accelerating, Repaired Just Three Years Ago
The city repaired the Tree Lane Bridge in March of 2020. Compare this post to see how it looked then. It’s amazing how much damage could be done in three years to a bridge that weathered multiple hurricanes and tropical storms for more than 50 years.
That’s a testament to insufficiently mitigated development upstream that sends ever greater volumes of water downstream – more than the opening under the bridge was designed for.
For a description of how jetting works, check this post. Basically, water backs up behind the bridge, putting greater pressure on the water flowing under the bridge.
Let’s hope the City can repair the Tree Lane Bridge again before school starts in the fall. The bridge borders Bear Branch Elementary School where 638 students attend classes.
Please check bridges near you and report any damage.
Posted by Bob Rehak on 6/12/2023
2113 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/06/20230612-DJI_0007.jpg?fit=1100%2C733&ssl=17331100adminadmin2023-06-12 21:28:172023-06-13 09:04:40Flood Damage To Tree Lane Bridge Over Ben’s Branch Accelerates
For a variety of reasons, many new developments seem to be “on pause” these days. Developers clear and grade land. Then it may sit undeveloped for months or even years.
This leaves exposed soil unprotected by vegetation. That makes it more susceptible to erosion for longer periods. And the eroded soil can clog streams and creeks with excess sediment. That reduces conveyance and can contribute to potential flooding. The EPA classifies sediment as the most common pollutant in American rivers and streams.
I am not alleging that all of the developments below have flooded other properties – though some have. But in extreme storms, they may contribute to conditions that increase flood risk.
That raises the question: Can we reduce that risk? That, of course, requires understanding what’s slowing development. But let me show you some examples of stalled developments first.
Unprotected Soil
No one keeps statistics on how long cleared land remains undeveloped. But suddenly, it feels as though stalled developments surround us. Below are pictures of just a handful taken in the last few months near the Montgomery/Harris County border.
Royal Pines in Porter
Royal Pines in Montgomery County on White Oak Creek has flooded neighbors’ properties multiple times in the last six months. White Oak Creek actually rerouted itself across a portion of the development.Royal Pines border with White Oak Creek (in woods). Note sediment escaping propertyinto creek.After a 4-inch rain in January, White Oak Creek branched and started flowing across the cleared area.Truck of Royal Pines neighbor one day after being washed.Flooding isn’t the only problem.
The neighbor stated that she spoke with the MoCo Engineers’ office last Friday and the stormwater detention plan still had not been approved. According to the neighbor, the developer was told by the county last January to submit revised detention and berm plans. The engineer also requested the developer to divert the runoff away from the neighbor’s property. But the developer evidently went ahead and built a detention basin without revising the plans. The development still floods neighbors’ property after every appreciable rain.
New trailer park development in NW Harris County is sending sediment into the headwaters of Spring Creek. See below.
As you approach the creek, the slope increases…
…and despite the best efforts of the developer, sediment is escaping into the creek.A river of mud……is flowing into Spring Creek.
Townsen Landing in Humble
A small part of Townsen Landing in Humble. The developer cleared land, but no homes have been built in the last year.
Valley Ranch in New Caney/Porter
Valley Ranch Medical Center construction in November 202120 months later they were building detention basins and channels to connect them. In March 2023, uncontrolled runoff was sending sediment into a ditch behind homes and businesses along FM1314.
Multiple Reasons for Development Delays
To do something about development delays, you need to understand the causes first. Those most often cited by developers and media have to do with:
Regulations. For instance, Magnolia officials enacted a moratorium on permit applications in December 2022 over concerns the city’s water supply couldn’t keep pace with growth in the area. The moratorium impacts new as well as current development projects.
Developers rank permitting delays as one of their biggest headaches.
Increasing land prices push developers into marginal, flood-prone land as a way to help control costs. But such land also causes permitting delays. Developers struggle with extra layers of studies and approvals from flood plain managers that can slow projects.
Rising interest rates that may undermine developers/builders economic assumptions.
Shortages of building materials. For instance, a global cement shortage, often linked to the war in Ukraine, makes planning difficult for land developers and road builders. According to a source at the Houston Contractors Association, Texas pours more concrete annually than the next two states (CA and FL) combined.
The pandemic, which led to other supply and labor shortages.
Such issues often loom larger for less experienced developers whose pockets may not be as deep as their more experienced competitors.
Regardless, silt fences are woefully inadequate in dealing with issues such as these.
Need to Re-Evaluate Construction and Permitting Practices
Some suggestions. Many areas do not require a permit to clear and grade land. Developers may begin the process assuming normal permitting time for their plans, but then run into unforeseen hiccups. As regulations have gotten more complex in the post-Harvey world, this has become increasingly common. Perhaps we need to require:
Permit approvals before clearing and grading.
Vegetated buffers around the perimeter of properties during development.
Berms to protect neighbors and waterways during development
Clearing and installing drainage in a portion of a property before moving onto another portion of the property (phased development).
Governments throughout the region to standardize construction requirements.
Governments to hire enough people to review plans a timely way.
Some or all of the above.
Other ideas suggested by readers:
Do not develop on land not suited for development in the first place.
Stop developing so close to waterways.
Zone land to allow natural drainage to exist in harmony with human occupancy.
Keep some areas prone to flooding heavily vegetated permanently.
Half Billion Dollars for Sediment Removal
Sound expensive? Consider this.
Since Harvey, we have spent/plan to spend approximately a half billion dollars on dredging and sediment removal. Half of that has been spent on the East and West Forks of the San Jacinto, plus channels/streams around Lake Houston. The other half will be spent on sediment removal in:
Willow Creek
White Oak Bayou
Spring Creek
Little Cypress Creek
Greens Bayou
Cypress Creek
Barker Reservoir
Addicks Reservoir
We must find a compromise that works for everyone. People need places to live. Especially places that don’t flood.
Posted by Bob Rehakon June 7, 2023
2108 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2023/06/20221006-DJI_0849.jpg?fit=1200%2C799&ssl=17991200adminadmin2023-06-07 19:53:512023-06-11 13:21:23How Development Delays Can Impact Flooding
The problem: Changes affect both water quality downstream and land development upstream. That’s why the rules change so often. Competing interests! Public health and safety vs. economic expansion.
The Cuyahoga River caught fire a total of 13 times dating back to 1868. It is still rated one of the most polluted rivers in America by almost every group that compiles lists. Photo: Cleveland State University Library.
The photographers took about 81,000 images, more than 20,000 of which were archived. At least 15,000 have been digitized by the National Archives. They form a time capsule showing the way things were.
Warning: These images are disturbing…for people on both sides of the political net.
Why the Changes This Time?
The AP article by Jim Salter and Michael Phillis says, “The Trump-era rule, finalized in 2020, was long sought by builders, oil and gas developers, farmers and others who complained about federal overreach that they said stretched into gullies, creeks and ravines on farmland and other private property.”
However, the writers continued, “…the Trump rule allowed businesses to dump pollutants into unprotected waterways and fill in some wetlands, threatening public water supplies downstream and harming wildlife and habitat.”
They quoted Kelly Moser, Senior Attorney for the Southern Environmental Law Center’s Clean Water Defense Initiative. She said, “Today, the Biden administration restored needed clean water protections so that our nation’s waters are guarded against pollution for fishing, swimming, and as sources of drinking water.”
At Issue: Definition of “Waters of the U.S.”
Meanwhile, courts at various levels are still pondering the definition of “Waters of the U.S.” At issue: How far up in the branching structure of a river may the government enforce regulations? As far as it’s navigable? One level up from that? Two? Three? Infinitely? And do the rules apply to desert areas the same way they do to subtropical areas like SE Texas?
The Biden administration decision is a setback for various industries. It broadens which wetlands, streams and rivers can be regulated under the Clean Water Act.
But given the impacts to public health and the immense economic interests at stake, this won’t be the last time we see the rules change. An army of lobbyists is likely mobilizing right now.
Local Impact
Several developments in the Lake Houston Area contained wetlands affected regulation changes. Consider, for instance, the case of Woodridge Village. The Army Corps ruled that it contained wetlands, but that the wetlands didn’t fall under their jurisdiction because of rules in effect at the time. So there was no violation of the Clean Water Act. Hundreds of homes in Elm Grove and North Kingwood Forest flooded, partially as a result of the environmental destruction.
Confluence of Spring Creek and West Fork by 59 Bridge. TCEQ found that Liberty Mines discharged 56 million gallons of white waste water into the West Fork.Repeated and multiple breaches atTriple PG mine discharged sediment-laden water directly into Caney Creek. This one lasted for months.
Searching on the word “breach” in ReduceFlooding.com pulls up 116 stories, many of which show multiple breaches.
But mining isn’t the only upstream issue at stake. So is sediment pollution from new development.
Drainage ditch in Artavia.March 2020 in West Fork watershedEroding ditch in Colony Ridge (East Fork Watershed) due to lack of backslope interceptor systems and grass.
Making Private Expenses a Public Cost
The EPA lists sediment as the most common pollutant in rivers, streams, lakes and reservoirs. It has contributed to flooding thousands of homes in the Lake Houston Area.
West Fork mouth bar almost totally blocked the river where it meets Lake Houston.East Fork Mouth Bar grew 4000 feet in two years between Harvey and Imelda.
Both mouth bars above have since been dredged at great public expense, but abuses continue. I just wish we could all find a way to live together. This should not be a case of health and safety vs. economic development. We need all three for communities to prosper.
Posted by Bob Rehak on 1/2/23
1952 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/11/RJR_4154.jpg?fit=1500%2C1000&ssl=110001500adminadmin2023-01-02 11:04:302023-01-02 11:49:14Biden Changes Trump’s Changes to Water Regulations
The month after Woodridge Village flooded Elm Grove Village and North Kingwood Forest for the first time in May, 2019, the TCEQ investigated construction practices there. In the ensuing months, six investigations found 13 violations on the Woodridge site.
Correctly identify receiving waters for the discharge
Implement and maintain effective best management practices.
On TCEQ Commissioners Docket for September 9
Item 29 on their docket reads:
No. 2019-1513-WQ-E. Consideration of an Agreed Order assessing administrative penalties and requiring certain actions of Double Oak Construction, Inc. in Montgomery County; RN110478583; for water quality violations pursuant to Tex. Water Code chs. 7 and 26 and the rules of the Texas Commission on Environmental Quality, including specifically 30 Tex. Admin. Code ch. 60.
Water samples taken by the investigators showed that at the outfall:
Total Suspended Solids were 70 times higher compared to upstream
Total Dissolved Solids were almost 18 times higher.
Double Oak had been hired to clear and grub the site. That means removing trees and roots.
Unchecked erosion from site polluted water downstream with suspended solids 70 times higher than upstream.Abel Vera had to grab his car to avoid slipping in ankle-deep sediment on Village Springs. Vera lives next to Woodridge.
Definition of Agreed Order
This enforcement action by the TCEQ falls into a category called an “Agreed Order.” A website called USLegal.com defines an agreed order as: “An Agreed Order refers to a written agreement submitted by the parties to a case resolving the issues between them. Once the agreed order is approved by the court and entered in its minutes, it becomes the order or decree of the court with all of the force and effect that any order would have after a full hearing prior to adjudication.”
However, they add: “…until then, an ‘agreed order’ is no order at all, but merely an agreement of the parties. It has no significance … until a judicial … decision gives it significance.” TCEQ Commissioners will take that step on September 9.
Double Oak Penalties Unclear
Documents supplied in response to a FOIA request did not discuss what the penalties might entail for Double Oak. The company left the construction site long ago. It has since been sold to Harris County Flood Control and the City of Houston for a regional stormwater detention basin and sewage treatment plant. So it’s not as if Double Oak can make good by simply agreeing to clean up its act.
Typically, such cases involve a modest fine. The significance in this case: Double Oak apparently is admitting wrongdoing before a decision or settlement has been reached in hundreds of homeowner lawsuits downstream. More on those at a later date.
1463 Days after Hurricane Harvey and 712 Days since Imelda
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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/05/ElmGroveFlood_15_01.jpg?fit=1500%2C1000&ssl=110001500adminadmin2021-08-31 19:24:382021-08-31 19:32:47TCEQ Commissioners to Consider Agreed Order With Double Oak Construction on Woodridge Village Enforcement Action
At the very end of this post, I make some recommendations to strengthen BMPs, and describe how to submit public comments.
Structural Controls
Structural controls do several things:
Divert runoff away from disturbed areas
Reduce runoff velocities
Filter sediment
Remove sediment by ponding.
They include the following.
Temporary Structures (Section 2.2.1)
Installed before and during construction. After removing temporary stormwater controls the areas disturbed by the temporary structures must be revegetated.
Permanent Structures (Section 2.2.2)
Permanent structures remaining after construction. Once construction of areas outside of the sand-mining pit has ceased, permanent structural control BMPs must be implemented and operational.
Diversion Ridges, Berms or Channels of Stabilized Soil (Section 2.2.3)
These divert runoff into “sediment basins.” If they remain in place more than 30 days, they must be covered with temporary or permanent vegetation. Maximum allowable drainage area is five acres.
Silt Fences (Section 2.2.4)
Silt fences capture sediment from sheet flow. Six to eight inches of the fence material must be buried in a trench about four inches deep and four inches wide. Silt fences that are not buried have no useful function. They must never be installed across streams. Fencing must be removed when sediment deposits reach one-half the fence height.
Straw Bales (Section 2.2.4 Continued)
Can also be used as sediment barriers in small areas. Maximum grade: 3:1. Water depth must not exceed one foot at any point. Bales with bindings must be entrenched a minimum of four inches and anchored with stakes. Straw bales that are not buried are improperly installed.
Sediment Basins (Section 2.2.5)
Allow retention of sediment “prior to discharge” or recycling. Side slopes must be 2:1 or less.Sediment must be removed when the volume has been reduced to 27 cubic yards per acre of drainage area. Dikes must be well compacted and vegetated. Installed prior to construction but not in flowing streams. Use diversions to direct drainage to basins.
Riprap outlet protection must be placed at the outlet end of culverts or channels to reduce the depth, velocity, and energy of water so that the flow will not erode the receiving stream.
Check Dams (Section 2.2.7)
Small dams across swales or drainage ditches that reduce flow velocity and erosion. Not used in flowing streams. Maximum height: two feet. Center must be at least six inches lower than the outer edges to prevent erosion around the edges. The maximum spacing between dams must be such that the toe of the upstream dam is at the same elevation as the top of the downstream dam.
Accumulated sediment must be removed from behind the check dams when it reaches one half the dam height.Erosion around dam edges must be corrected immediately, ensuring that the dam center is six inches lower than the edges.
Construction Entrance/Exits (Section 2.2.8)
Aggregate must stabilize entrances and exits to reduce sediment tracked onto public roads. Aggregate must be at least six inches thick and 50 feet long. Tire washing may also be needed.
Housekeeping Practices (Section 2.2.9)
Petroleum products, paints, solvents, litter, debris, sanitary waste, and sediment from unstabilized areas, TCEQ BMPs specify:
Designated areas for equipment maintenance and repair;
Waste receptacles at convenient locations;
Regular collection of waste;
Protected storage areas for chemicals, paints, solvents, fertilizers, and other potentially toxic or hazardous materials; and
Control measures must be installed to control pollutants in stormwater after construction is complete. These controls include, but are not limited to:
Retention ponds. Minimum volume is the first inch or half inch of stormwater runoff containing the first flush of pollutants.
Vegetated Swales and Natural Depressions. There are grass-lined areas that filter sediments from runoff, thus helping to prevent erosion. Vegetated swales must have side slopes of 4:1 or less.
General
As with vegetative controls, operators must inspect structural controls once every seven (7) calendar days. That includes controls in areas used for storage of materials; maintenance areas; plus site entrances and exits.
Operators must replace or modify ineffective or damaged structural controls “in a timely manner, but no later than the next anticipated storm event.”
Recommendations for Public Comment Structural Controls
As we saw in yesterday’s post on vegetative controls, I have often seen gaps between real and ideal. However, for this post, I realized in looking back through thousands of aerial photos today, that I have never photographed one:
Stabilized channel
Silt fence
Straw bale
Check dam
Outlet stabilized by riprap or
Vegetated swale
…on a sand mine site. Period. Let alone one that met these requirements.
I’m not saying they don’t exist. I’m just saying that I’ve never seen them on the days I flew over.
Maybe operators feel they don’t need them. Or maybe they’re just not using them for other reasons.
So once again, I recommend that you write the TCEQ and ask them to put teeth into their BMP requirements.
In addition, I recommend you request:
Stronger wording on the general requirement to fix damaged or ineffective structural controls in a “timely manner.” That’s just too subjective. It lets operators defer maintenance way past the point it may be needed.
Clarification on “prior to discharging” in section 2.2.5. Are operators capturing sediment only to discharge it into the river at a later time? What do they mean by discharge? Where?
Detention ponds big enough to catch an inch of rain in an area where Atlas 14 requirements specify 16.9 inches of rain in 24 hours? (Section 2.2.10) That seems wholly inadequate. Harris County Flood Control District recommends minimum detention volumes for developments at .65 acre feet per acre for areas up to 640 acres. That’s about 8 inches of rainfall.
Please submit your thoughts on structural control and other BMPs to the TCEQ by emailing Macayla.Coleman@Tceq.Texas.gov with the subject line “BMPs Guidance Document” before August 19, 2021.
The house you save could be your own.
Posted by Bob Rehak on 8/13/2021
1445 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/11/RJR_4245.jpg?fit=1500%2C1000&ssl=110001500adminadmin2021-08-13 20:12:092021-08-13 20:33:34Sand-Mine Structural Control BMPs Could Make Difference in Next Flood
After a few drier days during the Memorial Day weekend, wet weather is returning and will last into next week. We should see a high chance (50% or greater) of thunderstorms every day for the next week.
Pattern Similar to Last Month Setting Up
According to Harris County Meteorologist Jeff Lindner, the upcoming pattern will resemble the heavy rains of early last week and similar patterns in 2015 and 2016. Slow moving low-pressure systems over the southwest US will send multiple disturbances across Texas starting today and lasting into early next week.
Harris County Flood Control inspects damage from heavy rains in May to recently repaired Ben’s Branch. Photo courtesy of Chris Bloch.
Onshore winds will ensure a steady influx of Gulf moisture, high humidity and rainfall production. Disturbances will emerge from northeast Mexico into central and south central Texas nearly every day. Clusters and complexes of thunderstorms will develop and move east into the Houston region.
Difficult to Precisely Predict Heavy Downpours
“When exactly each disturbance will rotate out of Mexico is uncertain. And what state the local air mass will be ahead of each disturbance will also be hard to determine,” said Lindner.
But this pattern, he continued, “will support complexes and clusters of thunderstorms from Tuesday onward – with both a heavy rainfall and marginal severe weather threat. Some days will likely have higher threats of both.”
Widespread rainfall of 3-5 inches is likely over the next several days.
Jeff Lindner, Harris County meteorologist
While our minds may be inclined to spread such totals out evenly over the course of 5-7 days, “that is usually not how it works,” warns Lindner. “At this time of year, we could see 1-3 inches fall in a few hours or less as clusters and complexes move across the region.”
Grounds are still wet from the 10-15 inches of rainfall in May. It will not take much rainfall to trigger run-off and renewed rises on area watersheds, especially as rainfall totals accumulate over time.
Posted by Bob Rehak on 6/1/2021, based on information provided by HCFCD
1372 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/06/Screen-Shot-2021-06-01-at-8.49.26-AM.jpg?fit=1200%2C658&ssl=16581200adminadmin2021-06-01 09:55:452021-06-01 10:06:27High Chance of Thunderstorms Every Day into Next Week
“Backslope interceptors” help prevent erosion that can clog drainage ditches and contribute to flooding. Most people have probably seen them, but never paid much attention to them. Nor do they understand can reduce ditch maintenance costs by lengthening maintenance intervals. This photo essay shows what a difference they can make. All three counties in the Lake Houston Area require them, but Liberty County doesn’t enforce its own regulations. So the visual differences are dramatic.
What Are They? How Do They Work?
We’ve all observed water flowing through drainage ditches. But how does it get into the ditch? Broadly speaking, it can get into the ditch by a) flowing down the banks or b) through pipes. Option A increases erosion. Option B decreases it. B also reduces flood risk and the long-term cost of ditch maintenance.
What is a backslope interceptor? Imagine a small ditch (or swale) parallel to but offset from the main ditch. The swale captures runoff and overland sheet flow before it gets to the main ditch. The swale then funnels the flow into pipes that run under the banks of the main ditch. Keeping large volumes of water off those banks reduces erosion which could otherwise quickly fill the ditch with dirt and reduce its carrying capacity. If erosion reduces carrying capacity enough, water can flood nearby homes and businesses. The illustration below shows how backslope interceptors work.
Real-Life Examples
On 3/3/2021, I flew over three counties: Harris, Montgomery and Liberty. The “with/without” photos below illustrate the difference that properly constructed backslope interceptors can make. I shot the first one over the new Artavia development in southern Montgomery County. Note how the backslope interceptors let the developer establish grass on the banks of the ditch despite construction still in progress.
Ditches WITH Backslope Interceptors
Artavia ditch in Montgomery County. Note series of backslope interceptors behind the maintenance roads that flank the ditch.
Drainage ditch in Atascocita in Harris County. Again, backslope interceptors let grass establish on the sides of ditches, reducing erosion.
Wider shot along same ditch.
Ditches WITHOUT Backslope Interceptors
The rest of these examples came from Colony Ridge in Liberty County.
Lack of backslope interceptors has led to severe erosion. Runoff goes straight down the banks of ditch and into the East Fork San Jacinto.
Close up of same Colony Ridge ditch.
Role in Establishing Grass
The next two photos show the role of backslope interceptors in establishing grass. By preventing bank erosion from sheet flow, the interceptors give grass time to establish and grow, reducing erosion even more.
Ditch in Artavia, a still-developing area in Montgomery County, where developer has recently hydromulched to establish grass.
Liberty County ditch in newly developing part of Colony Ridge, also recently hydromulched. Without backslope interceptors, hydromulch has washed into bottom of ditch and will eventually wash away, leading to more severe erosion.
How Enforcing Regulations Can Reduce Costs, Flooding
Ironically, Liberty County drainage regulations updated in 2019 require developers to install backslope interceptors and plant grass on the banks of drainage ditches.
Page 100 states: “Erosion Control: All drainage facilities must be designed and maintained in a manner which minimizes the potential for damage due to erosion. No bare earthen slopes will be allowed. [Emphasis added] Various slope treatments, including turf establishment, concrete slope paving, and rip- rap, are accepted. Flow velocities should be kept below permissible values for each type of slope treatment. Interceptor structures and backslope swale systemsare required [Emphasis added] to prevent sheet flows from eroding the side slopes of open channels and detention facilities.”
Unfortunately, Liberty County does not enforce its own regulations.
When the developer eventually tries to turn Colony Ridge over to Liberty County, the county will inherit as massive maintenance burden because of non-compliance with these regulations. But even before then, the developer is creating rivers of mud that reduce the conveyance of ditches, and thus contribute to flooding nearby residents in Plum Grove.
This Colony Ridge drainage ditch in Liberty County is rapidly filling in. Residents use it for joy-riding in their ATVs, which further contributes to erosion.
The sediment also contributes to dredging and water purification costs for people downstream in Harris County.
Posted by Bob Rehak on 3/6/2021
1285 Days since Hurricane Harvey and 534 since Imelda
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.
