Mavera, a 1700-acre new development in southern Montgomery County at FM1314 and US242 has finished clearing a large section of land northwest of the intersection and started pouring concrete. Signs welcome visitors to model homes. The area, once laced with wetlands now has a massive linear detention pond and uses FM1314 for outflow control.
Looking east just north of US242 on right from over FM1314. Note wet areas in foreground. They correspond to wetlands in map below.Large green area immediately east of 1314 (diagonal) and north of US242 (bottom) correspond to wet areas in photo above. From US Fish and Wildlife Service National Wetlands Inventory Map
Areas west of FM1314 to Crystal Creek are also being cleared, but their current state of development is not quite as advanced.
Likewise, an area east of FM1314 has expanded north, almost to Gulf Coast Road. Neither is its drainage fully developed.
Looking NE at current limit of development. Gulf Coast Road runs diagonally from left to right just beyond tree line.
Long, Linear Detention
The development relies on a wide linear detention basin – more than a mile long! And that’s only the part east of FM1314!
Looking east toward upstream end of detention basin.
Two smaller basins also exist. One is currently by a small park and recreation center.
Looking WSW.Note small retention pond and rec center in upper right.
In the photo above, also note the small swales that outline lots. Will some drainage go overland? Or is underground drainage just not connected to the detention basin yet?
Same spot. Lower elevation. Looking west from eastern portion of Mavera. I’m not seeing any drainpipes from storm sewers entering pond yet.Note three new model homes near center of frame.
The development seems to have undergone a series of name changes. The land was originally known as the Denbury Tract. Later, construction plans and a drainage analysis refer to it as Madera. But now, the builders are marketing it as Mavera.
Screen capture of cover sheet from drainage planshowing first two names of development.
The drainage plans for Mavera (aka Madera/Denbury tract) rely on a hydrologic timing assessment (see last line in screen capture above).
The drainage analysis claims the development will have no downstream impact, but engineers didn’t study those areas. Nor did they study how new development upstream may have already shifted the peak of a flood.
Impact on FM1314?
Long linear detention schemes typically accelerate the flow of water. This one will rely on one culvert under FM1314 to hold back more than a mile of water collected from hundreds of acres. That will put a lot of pressure on FM1314 in a heavy storm.
Looking NW over FM1314. East is to the right. Water will flow west toward Crystal Creek out of frame to the left.
The roadway will act as a dam to detain water collected from almost all of the area shown in the photo below.
Looking east. Virtually all of the cleared area will drain through one culvert under FM1314. FM1314 runs left to right through the bottom of the frame. US242 is on right. Notice how channel is being widened, making culvert off-center. Did someone initially miscalculate or did plans change?
FEMA mapped most of this area in a ten-year flood zone. For the sake of potential home buyers, let’s also hope the engineers got the drainage calculations right.
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/2022/07/20220716-DJI_0152.jpg?fit=1200%2C799&ssl=17991200adminadmin2022-07-16 15:56:422022-07-17 11:25:25Mavera Wetlands Bite the Dust
How soon we forget. Hurricane Harvey was just 4.5 years ago. Since then I have documented dozens, if not hundreds of questionable practices that erode margins of flood safety.
It Didn’t Have to Be That Bad
Harvey was the largest rainfall event in the history of North America. However, with better regulations and construction practices, it didn’t have to be as destructive as it was.
Lax regulations;
Willful blindness;
Development and construction practices that pushed the safety envelope;
Relentless destruction of forests and wetlands near rivers and streams;
And homebuyers who didn’t realize their true flood risk…
…made Harvey’s destruction worse than it otherwise would have been.
No one factor by itself would explain Harvey’s destruction. But put them all together, and it’s like “death of a thousand cuts.”
The sheer volume of material – more than 1,000,000 words on this site – makes it difficult for people to see the big picture sometimes. To put 1,000,000 words into perspective, the average novel contains only about 100,000. So I’m condensing the website into a book that includes the themes below.
No One Wins Arguments with Mother Nature
During an interview with Milan Saunders and his daughter Lori, Milan said, “No one wins arguments with Mother Nature.” How profound! It doesn’t matter how many surveys, studies and engineer stamps you have on your home’s title. If you don’t:
Large islands built up during Harvey blocked both drainage ditches and rivers. Below, you can see a large sand island (top) built up at the confluence of the Kingwood Diversion Ditch where it reaches the San Jacinto West Fork at River Grove Park. This sand bar reached 10-12 feet in height above the waterline and helped back water up into Trailwood, the Barrington and Kingwood Lakes and Kings Forest. Before the Army Corps dredged this island, River Grove flooded five times in six months. It hasn’t flooded since.
The Kingwood Diversion Ditch and West Fork San Jacinto were almost totally blocked by sediment dams deposited during Harvey.
The second photo above was taken a few hundred yards downstream on the West Fork from the first. It shows “Sand Island” – so nicknamed by the Army Corps. It took the Corps months to dredge this island which they say had blocked the West Fork by 90%.
A certain amount of this sedimentation can be explained by natural erosion. But mankind also contributed to the sheer volume by other practices which I will discuss below.
Influence of sand mines of West Fork San Jacinto water quality.
End the War on Wetlands
Wetlands are nature’s detention ponds. During storms, they hold water back so it won’t flood people downstream. But we seem to want to eradicate wetlands. The images below show the Colony Ridge development in Liberty County. Wetlands (right) are being cleared (left) to make way for the world’s largest trailer park. The acceleration of runoff wiped out FM1010 during Harvey. The road still has not been repaired.
Colony Ridge in Liberty County.
Conservation Costs Much Less than Mitigation
Halls Bayou at I-69 near Fiesta. Image on left shows whole subdivisions that that to be bought out before detention ponds on right could be built.
Respecting Individuals’ Property Rights While Protecting Others’
In Texas, it sometimes feels that an individual’s right to do what he/she wants with property trumps others’ rights NOT to flood. You may think you’re protected by all those public servants reviewing and approving plans. But what happens when developers and contractors decide to ignore the approved plans? Here’s a prime example: the Laurel Springs RV Resort near Lakewood Cove.
About 10% of all the water coming down the West Fork at the peak of Harvey came from Crystal Creek in Montgomery County. But the wetlands near the headwaters of Crystal Creek are currently under development. And the developer is avoiding building detention ponds with a “beat-the-peak” survey. This loophole allowed by Montgomery County says that if you get your stormwater to the river faster than the peak of a flood arrives, then you’re not adding to the peak of a flood and you don’t have to build detention ponds. So developers conduct timing surveys to reduce costs and maximize salable land.
What happens when upstream areas develop without consideration for the impact on downstream property owners.
Of course, speeding up the flow of water in a flood is the opposite of what you want to do. To reduce flooding, you should hold back as much water as possible.
The graph on the right shows what happened on Brays Bayou without suitable detention upstream. Floodwaters peak higher, sooner. Harris County has spent more than $700 million in the last 20 years to remediate flooding problems along Brays.
How much will we need to spend when more areas like Madera get built upstream on the West Fork?
How Quickly We Forget!
FEMA’s Base-Flood-Elevation Viewer shows that in that same area, developers have already built homes that could go under 1-5 feet of water in a 100-year flood. These homes are actually in a ten-year flood zone. And yet more homes are being built nearby. On even more marginal land!
In recent years, the price of land as a percent of a new home’s cost has risen from a historical average of 25% to approximately 40% today. This puts pressure on developers to seek out cheaper land in floodplains, reduce costs by avoiding detention pond requirements, pave over wetlands, and reduce lot sizes resulting in more impervious cover. All contribute to flooding.
Of course, smart homebuyers would not make such risky investments. But few lack the expertise to gauge flood risk. Educating such homebuyers will be one of the major objectives of the book I hope to write.
Posted by Bob Rehak on 2/23/2022
1639 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=110001500adminadmin2022-02-23 18:55:302022-02-23 19:09:31How Soon We Forget!
Every once in a while, thoughts collide in a way that makes you see the world more clearly. Such a collision happened today. I suddenly realized that Texas, the state that leads the nation in billion-dollar, weather-and-climate related disasters, also has many developers plus city and county officials pushing back against higher minimum drainage standards that would reduce flooding. At a time when those disasters are increasing in frequency!
How Proposed Drainage Standards Will Affect Developers
I replied, “The proposed changes would force developers in the future to install detention ponds and storm drains large enough to help reduce flooding. It would also prohibit them from reducing the floodwater storage capacity of the 500 year floodplain. Finally, it would force them to raise the level of homes above the 500-year floodplain or flood-proof them.”
Then I added, “From a flood prevention point of view, these are all good things. But from a developer’s point of view, they add expense. If you buy a home in an area that complies with these standards, it will probably mean a higher-priced, but much safer home. I hear that developers and some civic officials are already pushing back against these proposed changes.”
Natural Disaster Costs, Frequencies
After sending the reply, I went to the NOAA site to find information about natural disasters, their costs, their frequency and their primary locations.
The last decade had twice as many billion-dollar weather disasters as the previous decade and four times more than the decade of the 1980s. The last five years had 69% of all such disasters in the entire 40 year period.
Tropical Cyclones and flooding comprised 29.5% all these billion-dollar disasters.
Reason for Increasing Costs, Even After Adjusting for Inflation
In explaining these rising costs, NOAA says, “These trends are … complicated by the fact that much of the growth has taken place in vulnerable areas like coasts and river floodplains. Vulnerability is especially high where building codes are insufficient for reducing damage from extreme events.”
Texas Leads Nation
And who leads the nation in billion-dollar, weather-and-climate-related disasters? Texas.
Connecting Some Tragic Dots
So there you have it.
The state with the most billion-dollar disasters has many developers and civic leaders pushing back against higher minimum drainage standards at a time when major weather disasters are increasing.
New Northpark Woods development in Montgomery County next to San Jacinto West Forkand its sand pits.
Posted by Bob Rehak on 6/8/2020
1014 Days after Hurricane Harvey and 263 after Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/06/map_events_per_state_cumulative.png?fit=974%2C650&ssl=1650974adminadmin2020-06-08 16:19:232020-06-08 16:48:46Why Does the State that Leads the Nation in Billion-Dollar Weather Disasters Resist Minimum Drainage Standards?
In April, Harris County Commissioners directed the County Engineer and Executive Director of the Flood Control District to recommend minimum drainage standards for all communities in Harris County. The idea: to protect the County’s $2.5 billion flood bond investment. Lax standards in one place could undermine mitigation projects in another.
High-Level Recommendations
In May, the two executives came back to Commissioners Court. Here is what they recommended. These ideas apply to all cities within Harris County as well as those outside the county, but which drain into Harris County.
The recommendations must be adopted within municipal boundaries AND extraterritorial jurisdictions by December 31, 2020, IF the municipalities in question wish to partner with the county on any flood bond projects. That’s a $2.5 billion stick the county wields and that’s a powerful incentive.
Here are the recommendations:
Use Atlas 14 rainfall rates for sizing storm water conveyance and detention systems.
Require a minimum detention rate of 0.55 acre feet per acre of detention for any new development on tracts one acre or larger in size. However a single family residential structure and accessory buildings proposed on an existing lot is except from providing detention.
Prohibit the use of hydrographic timing as a substitution for detention on any project, unless it directly outfalls into Galveston Bay.
Require no net fill in the current mapped 500-year flood plain, except in areas identified as coastal zones only.
Require the minimum Finished Floor Elevation (FFE) of new habitable structures be established at or waterproofed to the 500-year flood elevation as shown on the effective Flood Insurance Study.
County Has Hired Engineering Firm to Identify Specific Changes
The County has hired an engineering firm, EHRA Engineering, to assist communities in evaluating and updating their policies and ordinances at no cost to the community.
End-of-Year Deadline
To help ensure participation, no partnership projects, including flood control or county roadway projects, will be constructed after December 31, 2020, in communities that have failed to implement these minimum standards. Projects started before that date may be continued only if communities are actively working to update their criteria.
Fix Flooding First Initiative About to Be Unveiled
The letter, signed by John Blount, Harris County Engineer, and Russ Poppe, Executive Director of Harris County Flood Control, also hints at something called a “Fix Flooding First” Initiative scheduled for roll out later this month. A Google search for “Fix Flooding First” turned up an initiative in Charleston, SC, but nothing in Harris County yet. Stay tuned.
Exact Text of Language Approved by Commissioners
Below is the exact text of the language in the two page letter unanimously approved by Commissioners and the County Judge.
The reference to hydrograph timing in the letter above refers to the Beat-the-Peak exemptions that Montgomery County offers to developers as an alternative to detention ponds. If developers can prove that their runoff will reach a river or stream BEFORE the peak of a flood, they can avoid building detention. The theory is that they aren’t adding to the peak.
The Artavia Development near FM1314 and the West Fork covers 2200 acres without having one detention pond. Ditches are designed to get water to the river ASAP.
Of course, that only encourages developers to get water to a river faster in a flood. That reduces the time of accumulation and adds to flooding downstream. It’s the exact opposite of what should happen to reduce flooding.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/06/20200421-RJR_0841.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-06-07 18:31:372024-02-07 12:32:46Minimum Drainage Standard Recommendations for Communities In or Draining Into Harris County
A friend, Dr. Matthew Berg, CEO and Principal Scientist of Simfero Consultants, observed that flooding and the corona virus are alike. The more I thought about that, the more intrigued I became. Controlling both requires similar strategies.
Controlling Convergence is Key
Of course, when looking at the corona virus, it spreads from “one-to-many.” And when looking at flooding, the relationship is reversed, “many-to-one.” But stay with me for a moment. Because similarities will become apparent at the point of convergence.
Dozens of creeks and streams flow into Lake Houston from approximately 2,600 square miles.
Creeks and streams from 2,600 square miles converge on Lake Houston during heavy rains. That can cause flooding. Likewise, thousands of corona virus victims could soon flood the area’s limited number of hospitals.
Harvard Study Shows Hospitals Rapidly Becoming Overwhelmed
Last week, ProPublic published an article, “Are Hospitals Near Me Ready for Coronavirus? Here Are Nine Different Scenarios.” The article is about a Harvard Global Health Institute study. It modeled different rates for the spread of the virus: 20%, 40% and 60% of the population infected over 6, 12 and 18 months. The authors then compared results against the number of available hospital beds in various areas.
Interestingly, they used the Houston region as their first test case. In only one of the nine scenarios, did we have enough hospital beds to handle the flood of corona victims. That scenario was for 20% infected (the smallest percentage) over 18 months (the longest period).
Darkest blue represents 6-month peak, middle blue a 12-month peak, and lightest an 18-month peak.
In the graph above, the areas shaded with crosshatching represent the normal baseline level of bed occupancy for non-corona patients in Houston hospitals. The colored areas represent the percentage of the area’s population projected to seek admission within a 6-, 12- or 18-month period.
2.8X Available Hospital Beds
The ProPublica article about the Harvard study goes into much more detail. It looks at all 50 states, the number of ICU beds, available ventilators, people etc.
In Houston, the researchers found, “The influx of patients would require 14,300 beds over 12 months, which is 2.8 times the available beds in that time period. The Harvard researchers’ scenarios assume that each coronavirus patient will require 12 days of hospital care on average, based on data from China.”
ProPublica Article on Harvard Study
One hospital administrator said, ““The reality is that you can’t create unlimited hospital beds and ventilators. We have what we have, so we really have to hope that it’s enough, and that we’re prepared enough.”
Flattening the Curve Prevents Avoidable Deaths
Said the authors, “By modeling the data over the three time periods, the scenarios illustrate how much the nation could “flatten the curve” with social measures to ensure hospitals have greater capacity to care for coronavirus patients.”
Epidemiologist Dr. Marc Lipsitch, head of the Harvard T.H. Chan School of Public Health’s Center for Communicable Disease Dynamics said, “The way to permanently stop new cases from setting off long chains of transmission is to have each case infect considerably less than one case on average. The numbers will go down. There will still be little outbreaks, but not big ones.”
Basically, Dr. Lipsitch argues that controlling the flood of victims early at the source is the only way to avoid overwhelming health care resources.
This YouTube video from Vox about Avoidable Deaths shows how slowing things down and flattening the curve helps everyone.
It’s much the same in physical flooding. Too much water in too little time overwhelms the available capacity of streams, rivers and lakes. Property is destroyed. People die.
The beat the peak loophole in MoCo regulations says that if developers can prove they can get their runoff to the river before the peak of a flood, they don’t have to build detention ponds. That’s what happened in the 2200-acre Artavia development. Of course, this incentivizes developers to get their water to the river ASAP.
And that’s exactly the opposite of what you need to protect lives and property downstream.
It’s kind of like saying, “Let’s infect everybody as fast as we can.”
Slowing down the spread of the virus will give researchers time to develop a vaccine or for the population to develop herd immunity … before hospitals become overwhelmed.
Unfortunately, there is no vaccine or herd immunity to protect downstream residents from greed. And there never will be. That’s why we need to close the “beat the peak” loophole before it’s too late.
Posted by Bob Rehak on 3/25/2020
939 Days after Hurricane Harvey
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/03/Vox.png?fit=1870%2C1042&ssl=110421870adminadmin2020-03-25 17:22:522020-03-25 17:22:57Parallel Between Flooding and Corona Virus
It all seemed somewhat academic at the time – unless you previously flooded from upstream development. Then along came Imelda. The absence of functioning detention ponds on Perry Homes’ Woodridge Village property underscored the need for adequate detention for the second time in five months when hundreds of homes downstream in Kingwood flooded.
The engineering company for the developer, Aliana, claims their calculations show that floodwater from Artavia will beat the peak of a flood to the West Fork by 35 hours. Dasa Crowell, PE, LJA’s Project Manager for Hydrology and Hydraulics, thus concluded, “This leads us to a conclusion that the peak flows generated by the runoff from project drainage area will have no impact on the WFSJR under proposed conditions, therefore detention is not required.” See page 56 of this PDF.
In fairness, the development does include a retention pond in Section 1 labeled as a detention/amenity pond. However, aerial photos show that it has only a few feet of excess storage capacity above its normal water surface elevation. See the plans here. It’s certainly not going to hold back a 100-year rain falling over 2200 acres.
Little Buck Amenity Facility/Pond. Note that as-built conditions appear smaller than plans.
Engineers seem to be relying on drainage channels to act as their detention basins, but as we will see, that comes with some risk. And one potentially bad assumption may invalidate the whole concept.
Because detention costs money and limits the number of salable lots, developers try to get their water to the river as quickly as possible so they can “beat the peak.” Of course, racing to get water to the river in a flood is the exact opposite of what you want to happen if you are a downstream resident. Normally, you want developers to hold water back as long as practical so as not to overwhelm downstream channel capacity.
Wilds said in part, “The analysis … demonstrates that the peak flow from the developed tract will pass through the downstream cross-section approximately 35 hours prior to the peak flow from the upstream watershed. The report indicates that the 10-year, 25-year and 100-year events were analyzed and concludes that the runoff from the project drainage area will have no impact to the San Jacinto River under proposed conditions.”
“Based on this information, this office offers no objection to the analysis as presented. Storm water detention will not be required for this development as long as the developed flows up to and including the 100-year event can be adequately conveyed to the San Jacinto River.” For the full text, see page 51 of this PDF.
The Executive Summary of the most recent update of the drainage impact analysis for Artavia states, “The November 2014 memorandum documents the analysis supporting no detention requirement; this analysis provides calculations showing that the proposed Star Ridge Ranch development (as it was then called) drainage system will safely convey the rainfall runoff for rainfall events up to and including the one-percent annual chance (100-year) storm event.”
Similarities Between Woodridge Village and Artavia
Finally, LJA pushed both the Woodridge and Artavia plans through the MoCo Engineers office right before the drainage criteria manual was about to be updated again with more stringent requirements.
LJA submitted both drainage analyses for MoCo approval within approximately a year of Hurricane Harvey before flood maps, rainfall statistics, drainage criteria, and construction standards were updated.
LJA Engineering was not only playing beat the peak, it was playing beat the clock again. This will be the first of several posts on Artavia. More news to follow.
Posted by Bob Rehak on 3/17/2020
931 Days after Hurricane Harvey
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/03/20200306-RJR_8998.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-03-17 21:29:282020-03-17 22:31:30LJA Engineers 2200-Acre Artavia Development in Montgomery County Without Detention Ponds
Three weeks ago, I posted about a loophole in Montgomery County regulations that lets developers substitute a flood routing study for detention pond requirements. Basically, if developers can show, using outdated and inaccurate information that runoff from their properties can “beat the peak” of a flood, they can avoid detention pond requirements. Fourteen developments currently underway in Montgomery County have used this loophole, according to Montgomery County Engineer Jeff Johnson.
Northpark Woods development in flood plain in Montgomery County
Yesterday, commissioners voted to leave the loophole open…at least until they receive the results of two studies…which have little to do with the loophole.
For those short on time, Community Impact summarized the meeting. However, please note, the author of the story misquoted Kingwood resident Jeff Miller. The misquote made it appear as though he spoke AGAINST closing the loophole when he spoke FOR.
Specifically, the article quotes him as saying, “I’ve come to the conclusion lack of retention REDUCES flooding.” He actually said, if you refer to the video, that, “…lack of retention CONTRIBUTES to flooding.” See 5:40 into the video. That one misquote changes the impression you would get of the meeting if you watched the entire video.
She also quotes an engineer as speaking against the loophole when he was actually noncommittal.
Commissioner Claims No Flooding Problem in MoCo
If you watch the entire video, you will see that one commissioner claims Montgomery County doesn’t have a flooding problem.
Toward the end of the 35-minute discussion, the talk turned to where the idea to close the loophole came from. Someone mentions Harris County. At that point, the discussion turned openly hostile.
The Judge and several commissioners felt that Harris County and the City of Houston could have solved their own problems had they added more gates to the Lake Houston Dam and started dredging after the 1994 flood.
One even blamed the lack of action downstream backed water up into Montgomery County.
New Studies Likely Won’t Affect Loophole
Both the County Engineer and the Montgomery County Flood Plain Administrator, Diane Cooper, pointed out that waiting on the results of the two studies would not likely alter the recommendation to close the loophole. For one thing, storm patterns, not just drainage characteristics, affect when peak flows hit an area. Drainage studies do not predict storms.
Commissioners Vote to Wait on Studies
In the end, the commissioners decided to wait for the results of the studies and leave the loophole open. The prevailing sentiment: that closing it now could affect investments in new developments.
Sometimes postponing a decision is a way of affirming the status quo. This was one of those times. I wouldn’t expect any action on closing this loophole for a long time. Maybe until spit freezes in August.
At a minimum, the San Jacinto River Basin Study will take another year. By then, this item will be long forgotten and MoCo developers will be counting their change.
Posted by Bob Rehak on August 28, 2019
729 Days since Hurricane Harvey
The thoughts expressed in this post represent my opinions on matters of public policy 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/2019/07/BCAeronautics-Oakhurst-West-9.jpg?fit=1500%2C1125&ssl=111251500adminadmin2019-08-28 09:26:082019-08-28 09:35:11MoCo Commissioners Leave Loophole Open that Lets Developers Avoid Detention Pond Requirements
