The Pulte Homes Mavera development at FM 1314 and SH 242 comprises approximately 2000 acres. Contractors first focused on clearing the 865 acres east of FM 1314. Photos taken on 7/22/2022 show they’re now also focusing on the 1150 acres west of FM 1314. Significant clearing in this western portion has already occurred. But more remains.
Map of Mavera At Ultimate Buildout
Mapexcerpted from developer’s 5/29/2020 memo to Montgomery County engineers.
Photos From West to East
Looking west from middle of western portion of Mavera. SH 242 in background. Channel drains into Crystal Creek which drains into West Fork San Jacinto by sand mine ponds in upper left.Looking south from same position. SH 242 cuts left to right through upper middle of frame. Ponds in background are sand mines bordering the San Jacinto West Fork.Looking east from same position at drainage coming from eastern portion of same development in distant background.Moving farther east toward FM 1314. Still looking east. SH 242 cuts diagonally from middle right toward upper left.Intersection of FM 1314 (bottom) and SH 242 (right). Looking east toward first section cleared and drained.Eastern-most section of Mavera.Looking NE.
Hydrologic Timing Used to Reduce Detention Requirements
Hydrologic timing studies attempt to show that a development can get stormwater to a river, such as the West Fork, before the peak of a flood arrives. The theory: if you aren’t adding to the peak, you don’t need as much detention.
In a hundred-year (1% annual chance) flood, this development claims it will not add to the peak. And therefore, it will have no adverse impact downstream. Yet it alone sends more than 16,300 cubic feet per second downstream toward West Fork sand mines and the Humble/Kingwood Area. That represents about 10% of the water that came down the West Fork during Harvey at this location.
Posted by Bob Rehak on 8/2/2022
1799 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/2022/08/20220722-RJR_0234.jpg?fit=1200%2C800&ssl=18001200adminadmin2022-08-02 13:00:232022-08-02 15:07:38Mavera Clearing More Land West of FM1314
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!
US Fish & Wildlife Map Shows Wetlands Dot Development
From US Fish & Wildlife Service National Wetlands Inventory. Madera will stretch past the left/right edges of this picture north of SH242 (the east/west highway near bottom.) FM1314 bisects picture from N to S in middle.
FEMA’s Base Flood Elevation Viewer Shows Flood Risk
Note that this survey shows only about a quarter of Madera (see below). The survey stops abruptly on the western margin. So, it is hard to say with certainty how bad flooding is throughout the rest of the site.
Yellow outline shows approximate outline of FEMA BFE survey shown above within Madera tract(black/white outline).
Option to See Depth of 100-Year Flood Waters
Also note that the purple area shows only the extent of 100- and 10-year floods. However, within the FEMA BFE viewer, you also have the option to select a layer that illustrates the depth of 100-year floodwaters. See below. (FEMA does not offer the option to show the depth of 10-year floods.)
FEMA’s estimated Base Flood Elevation Viewer showing extent of 100-year flood on left and depth on right.
Limitations of BFE Viewer
Of course, FEMA shows “estimated conditions” before developers bring in fill and alter drainage. But notice how a pre-existing development near Madera would fare in the same 100-year flood. You can see the close up below just above SH242 near the right edge of the image above.
FEMA shows that most homes in this development are still in the flood zone and would still flood to a depth of 1-2 feet in a hundred-year flood.
The street leading out of the development to SH242 could be under more than FIVE FEET of water in places!
FEMA Base flood Elevation Viewer
FEMA’s “Estimated Base Flood Elevation” is “The estimated elevation of flood water during the 1% annual chance storm event.” Structures below the estimated water surface elevation may experience flooding.” A 1%-annual-chance flood is also known as a 100-year flood. FEMA defines properties with a 1% annual chance of flooding as having “high flood risk” and says they have a 26% chance of flooding during the life of a 30-year mortgage.
Purposes of BFE Viewer
The agency developed its Base Flood Elevation viewer with several purposes in mind. To:
Inform personal risk decisions related to the purchase of flood insurance and coverage levels.
Inform local and individual building and construction approaches.
Prepare local risk assessments, Hazard Mitigation Plans, Land Use Plans, etc.
Provide information for “Letter of Map Amendment” (LOMA) submittals.
A LOMA lets the developer of a subdivision change the depiction of how flooding affects his/her subdivision. It’s the key to offering up-to-date risk assessments.
Full BFE Reports Available
FEMA also lets you download or print full BFE reports that give more specific estimates of flood depth at exact points, not just within a wide area.
FEMA’s BFE Viewer also gives you the option to print out a detailed flood-risk report by clicking on a point.
At the point shown above, you could expect 4.2 feet of water above the land surface in a 1%-chance flood. For the full report, click here.
Here’s what that point looked like last Saturday (1/22/22) from the air.
Madera development today at FM1314 and SH242, the point shown in BFE report above.
Cross-check this area on the maps above for wetlands and swamps! Then you can see why it’s so soupy.
BFE, Fill Not Mentioned in Drainage Analysis or Construction Plans
Text searches of Madera’s construction and drainage plans showed no references to “BFE” or “base flood.”
It seems unlikely that a “cut and fill” operation could excavate enough dirt from Madera’s drainage channel (dotted blue line with red parallel lines) and detention ponds to raise the whole site out the hundred-year flood zone. Five feet is a lot of fill for a 1700 acre site.
To raise a site this large, contractors would likely have to bring in fill from outside the property. But a text search from the word “fill” did not turn up any exact matches either.
So maybe they’re just planning to create the world’s biggest drain and hope to carry water off before it can reach homes.
However, a summary of the Madera master drainage plan notes…
“Coordination with MCED [Montgomery County Engineering Department] andadjacent property owners is recommended … on the potential need for inundation easements.”
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/2022/01/20220125-Screen-Shot-2022-01-25-at-3.52.07-PM.jpg?fit=1200%2C600&ssl=16001200adminadmin2022-01-27 06:08:242022-01-27 06:22:32New MoCo Development Being Built on Wetlands in 10-Year Flood Zone
