Tag Archive for: flood zone

New MoCo Development Being Built on Wetlands in 10-Year Flood Zone

At least part of Madera, a new 1,700-acre development in Montgomery County that straddles FM1314 immediately north of SH242, is being built on wetlands and is in a 10-year flood zone.

US Fish & Wildlife Map Shows Wetlands Dot Development

Magera Wetlands
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

From FEMA’s Base Flood Elevation Viewer. Extent of 100-year flood zone shown on left. 10-year flood zone shown on right.

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 BFE viewer
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 will eliminate wetlands but claims it will have no adverse impact.
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] and adjacent property owners is recommended … on the potential need for inundation easements.”

Revised Channel Alignment Memo, 2/19/21, Page 11

Still, engineers for the development claim it will have “No adverse impact.”

To review Montgomery County regulations regarding flood zones and drainage, see the documents under the “Construction Regs in Flood Hazard Areas” tab on my reports page. You’ll see plenty of opportunities for improvement.

Posted by Bob Rehak on 1/27/22

1612 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.

Preserve At Woodridge Claims No Flood Zone; Shades of LJA?

The Preserve at Woodridge is a novel single-family-home rental development going in off Woodridge Parkway between St. Martha Church and Kingwood Park High School. As with Woodridge Village, on the other side of the high school, the developer claimed the property was in no known flood zone. Even though it’s just outside the pre-Atlas 14 flood zones for Ben’s Branch, those zones are based on 40% less rainfall than the current standard for the Kingwood Area.

The Developer’s plans show this note about floodplains on virtually every page. Atlas 14 was implemented in 2018.

A major drainage ditch also runs along one side of the development and contributes to flooding along Northpark Drive almost annually. I owned property on the other side of that ditch for 20 years and can attest to frequent flooding.

And even though runoff calculations are based on Atlas 14 estimates, those estimates are based on Conroe’s rainfall which gets about 10% less than Kingwood (48 vs. 53 inches).

The ditch in question was developed for what is now the high school. The earliest photo of it in Google Earth dates to 1995. Around 2008, the ditch was extended to handle drainage from Woodridge Forest. The developer’s plans do not specify the capacity of the ditch as far as I can see.

LJA Parallels?

LJA, the engineer for Woodridge Village a block east also claimed “no floodplains.” That claim turned out to be tragically wrong. There were flood plains. They just hadn’t been mapped, like the ditch in question. And LJA used pre-Atlas 14 data in its calculations.

Hundreds of homeowners next to Woodridge Village in Elm Grove, North Kingwood Forest, Sherwood Trails and Porter subsequently flooded twice in May and September of 2019. They wound up suing Perry Homes, its subsidiaries and contractors, including LJA. Those cases recently settled.

The area immediately south of the Preserve at Woodridge includes approximately 40 businesses along Northpark Drive, the high school, St. Martha’s school, two churches, and dozens of homes in North Woodland Hills.

Let’s hope the engineers got this one right. Claiming “no floodplains” based on pre-Atlas 14 data and an old ditch whose level of service has diminished over time does not inspire confidence. How do they know for sure it won’t flood? But that’s not the only worry.

Rental Homes As Small as Studio Apartments

Guefen, the developer says it plans to build 131 homes on the 17 acres you see below. But the detention pond takes up five acres. That makes about 11 homes per acre of usable land with about 5 feet between many homes. You can see how close they are in the photo below.

First foundations going in (lower left). Photo taken on 12/31/2021.
Reverse angle shot shows 5 acre detention pond on 17 acre development. Ditch in foreground joins Ben’s Branch north of Northpark Drive.
Foundation forms in NW corner of subdivision along Woodridge Parkway. See corresponding plans below. Note how three of these homes could fit in the back yard of the home in the upper right corner of the photo.
Five of the eight homes above will have access only by sidewalks, not streets.
The same holds true for most of the homes in the subdivision.

In case of an emergency, that firetruck may be parking 250 feet away from some homes. That’s almost the length of a football field.

According to RentCafe.com, the average size of an apartment in Houston is 881 square feet. These detached rental homes will range in size from 668 square feet to 1,255 square feet. At the low end of that range, the square footage is about that of most studio apartments. For those of you who have never lived in one, a studio apartment has one big common area that triples as a living room, bedroom, and kitchen. Only the bathroom has walls.

Posted by Bob Rehak on 1/3/22

1588 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.