Tag Archive for: floodplains

Colony Ridge Buying Up Floodplain Land in Huffman

Colony Ridge Land, LLC, developer of the world’s largest trailer park in Liberty County, is buying up Harris County property in the floodplain of the East Fork San Jacinto. Since the property in the Cypress Point subdivision was originally platted, flood maps changed in 2001 and are in the process of changing again. Most of the properties face serious flood risk that the current flood maps may not communicate.

Land Remains Uncleared

Development has not yet started. The land is still heavily wooded…so much so, in fact, that dirt roads developed in the 1980s have become overtaken by trees and undergrowth. They are barely passable according to one person I talked to.

Colony Ridge has acquired at least 19 (but not all) properties within red area.
What the partially developed area looked like in 1988. Note unpaved roads nearest river.

Back in the late 1980s, the original developer cleared space for roads and platted the land going down to the East Fork. But today, paved roads stop about a quarter mile short of the river. From the air, those old dirt roads look like a slight indentation in the forest canopy.

Looking NE from over the utility corridor that forms the southern limit of the area. East Fork on right flows toward camera.
Looking NE from farther north. Old roadway appears as a crease in the jungle.
Still looking NE. Note how pavement on Birchwood Drive stops short of entering area.
Reverse angle looking S toward Lake Houston visible as blue streak below horizon in upper left. Lake Houston Park on right.

The Big Question

Why did the original developers stop short of paving roads all the way to the river? The answer likely has something to do with floodplains. Note in the image below how several of the lots border or lay within the floodway. Many more lay within the 100- and 500-year floodplains.

How Bad Could Flooding Be?

But those floodplain maps are outdated and can mislead. High-water marks established by HCFCD and contour maps by the U.S. Geological Survey suggest this property has flooded seriously at least 8 times in the last 20 years.

Elevation profile from USGS National Map

From the East Fork to the end of Oaknoll Drive, the elevation rises from approximately 42.5 feet to 67 feet. The 24.5-foot difference might sound like a lot. But consider this.

In 1994, the flood of record for the East Fork in this area (before Harvey), crested at 76.2 feet. That would have put the highest property near Oaknoll under 9 feet of water. The lowest property near the river would have been under 33.7 feet of water.

Then came Harvey. At the nearest gage, the East Fork crested at 81.2 feet.

That would have put the highest and lowest properties under 14.2 feet and 38.7 feet of water respectively.

All figures were computed using the elevation profile function in the USGS National Map, and cross referencing the results with the Harris County Flood Warning System gage at FM1485.

Even though most of the acquired properties are shown in the 500-year flood plain, most of them have been under water eight times in the 20 years since 1994.

Approximate high water marks from HarrisCountyFWS.org gage at FM1485 and East Fork.

In fact, most of the undeveloped lots likely flooded in an unnamed and already forgotten flood in April of this year.


Official Floodplains Expanding

Floodplains change with better understanding of the climate, upstream development, and better measurement technologies, such as LIDAR. Our current flood maps were developed after Tropical Storm Allison in 2001. But we’ve gotten a lot smarter about flood mapping since then.

That’s why Harris County Flood Control District and FEMA are updating flood maps for this area. The floodplains you see above will likely expand by 50% to 100% according to preliminary guidance from Harris County Flood Control. FEMA is in the process of certifying revised maps and should release them later this year or early next for public comment.

From MAAPnext.org.

Are Readings from FM1485 Analogous to Cypress Point?

Give or take few feet, the flood depths cited above are probably in the ballpark. Even if the high-water marks at Cypress Point are a few feet lower, they still represent serious flooding.

HarrisCountyFEMT.org shows that the width of the floodplain at FM1485 and Cypress Point, lower left, does not vary significantly.

One of the region’s leading hydrologists who has studied this area extensively felt the flood heights at FM1485 would translate well to Cypress Point where Colony Ridge is acquiring property. Colony Ridge has purchased at least 19 properties in the affected area. The map below shows where they are.

Note how virtually all purchases happened after Imelda, which would have put even higher properties under almost six feet of water.

Another property valuation report shows how the land value decreased 73% after Imelda in 2019. Colony Ridge purchased most of the properties in 2020. Bargain hunting?

Homes on Stilts Likely Unaffordable for Colony Ridge Target Market

It’s not clear what Colony Ridge plans to build on this property. However, the company has a history of selling land to Hispanic immigrants, then letting them clear their own lots and bring in trailer homes.

Many may not have a firm grasp of English. Few likely understand flood risk, especially the nuances of flood maps in flux. And Colony Ridge typically “owner finances,” meaning buyers don’t go through banks which would require flood studies and flood insurance before making a mortgage loan.

Alleged abuses are so common that whole websites have been set up to chronicle them.

Under today’s guidelines for developing land in floodplains, especially this deep in floodplains, homebuilders would likely have to elevate homes on stilts. And elevating homes 35 feet high would likely make them cost prohibitive for most of Colony Ridge’s primary target market.

Watch this one closely to make sure that no rules get broken.

Posted by Bob Rehak on 8/4/23

2166 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.

Developer Seeks City Approval to Expand Commons of Lake Houston into Floodplain – Without Detention Ponds

Clarification: General plans, as described below, are primarily about street layouts. However, many people have been trying to raise awareness at the Planning Commission that street patterns are affected to a significant degree by the volume and and layout of drainage and detention features. And, of course with Atlas 14 that is more true than ever. Danny Signorelli, CEO of the Signorelli Companies, took issue with this post. I offered him an opportunity to print a rebuttal verbatim. He refused the offer.

Signorelli Companies have filed a general plan with City of Houston Planning Commission for a new development on the San Jacinto East Fork. It’s called “Crossing at the Commons of Lake Houston.”

Second Time Around for Developer

According to residents in other parts of the Commons, Signorelli tried to develop this property before and reportedly wanted to add 4-6 feet of fill to the floodplain. It’s not yet clear what they have in mind for this iteration of the project. However, comparing the general plan to FEMA’s National Flood Hazard Layer Viewer shows that parts of the development are still in the flood plain. (See below.)

No Detention Ponds Shown on Plans

The general plan filed with the planning commission also shows that the developer shows no plans for detention ponds on the property. A best practice to reduce flooding is to “retain your rain.”

General plan filed with the City of Houston Planning Commission shows no detention ponds. For a large, high res PDF, click here.


Here are satellite and close-up views of where the new subdivision would be relative to the the surrounding area and existing parts of the development.

Crossing At the Commons of Lake Houston is in the Huffman area opposite Lake Houston Park and East End Park on the west side of the East Fork.
Crossing at the Commons of Lake Houston relative to existing streets in the Commons. From General Plan inset.

Floodplain Issues

Parts of the proposed development will be in the floodplain. And those floodplains will soon expand to include even more homes. See the two dotted lines below.

Close up of PDF above shows how 100-year floodplain (dotted line on left) and 500-year (dotted line on right) would impact proposed homesites. Note the drainage easement in the lower left.
FEMA’s National Flood Hazard Layer Viewer shows parts of the proposed new 75.3-acre subdivision would be in the 100- and 500-year floodplain.

Ironically, just last night, the City of Houston and its partners (Harris County Flood Control, Montgomery County and the SJRA) presented a draft of the findings of the San Jacinto River Master Drainage Plan. In it, they recommended avoiding flood plain development to keep people out of harm’s way. See slide below from their presentation.

Slide from San Jacinto River Master Drainage Plan Draft Report shows how adding fill to flood plains can affect other homes in area.

The presenter also discussed how the floodplains were expanding due to revisions of flood maps based on new hydraulic and hydrologic modeling not yet been shared with FEMA.

The 100-year flood plain in many areas will like expand well into the 500. And the 500-year flood plain will likely expand into areas previously not shown in ANY floodplain.

San Jacinto River Master Drainage Plan Draft Report 8/13/2020

Thus, the number of homes affected by floods could greatly expand beyond the number shown above.

Drainage in Commons Already a Problem

Plans also show that homes will be built very close to a drainage easement. Yet existing ditches in the Commons are eroding badly due to lack of maintenance. Below is a picture of one taken in January last year. Residents say the trees are still there and the erosion became much worse during floods in May and Imelda.

Commons drainage ditch photographed last year.

Less Than One Fourth of Property Now Under Consideration

The tract is 332 acres, but only 75.3 is proposed for development at this time.  It is entirely located within the incorporated limits of the City of Houston. The entire tract is adjacent to COH flooding easements for Lake Houston. 

How to Voice Concerns, If You Have Them

Here’s how you can voice concerns, if you have them. The City Planning Commission will hold virtual meetings until further notice. So it’s very easy to make public comments. You can sign up to speak by going to the Planning Commission Home Page.

The next Planning Commission meeting is Thursday, August 20, 2020. If you’d like to speak, you must sign up at least 24 hours before the meeting.

Use the online speaker form at https://www.tfaforms.com/4816241 or submit comments on an item via email to speakercomments.pc@houstontx.gov.

Speakers have only TWO MINUTES. Key points to consider:

  • Floodplain will officially be expanding soon.
  • Some of these homes are already in it.
  • Many more soon will be.
  • That could require fill.
  • And fill will make flooding worse for other homes near the river on both sides.
  • No detention ponds or drainage plans are shown.
  • The Planning Commission should consider these things.

Posted by Bob Rehak on 8/14/2020

1081 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.

Why the City Needs Regular River Surveys and Maintenance Dredging

Three months after supposedly reaching an agreement in principle to remove the mouth bar, FEMA, the Army Corps, the State and City still have no agreement in writing. From Day 1 of negotiations, FEMA and the Corps have consistently said they can’t address pre-Harvey conditions. I’m beginning to believe them. How did we reach this impasse and how can we move forward?

FEMA’s Dilemma

The Stafford Act (FEMA’s enabling legislation) prohibits FEMA from funding repairs not directly related to Harvey. But, because the City conducted no surveys after the Memorial or Tax Day Floods, it cannot prove how much came from Harvey. Yet it has asked FEMA and the Corps to remove the entire mouth bar.

The City’s Dilemma

The City of Houston has done little to maintain Lake Houston, especially the West Fork of the San Jacinto near Kingwood. Lack of regular surveys and maintenance dredging make city officials look like they’re trying to get others to clean up their mess.

Historical Perspective

Decades ago, after the 1994 flood, the City hired Brown & Root to study sedimentation in the lake, which includes about 13 miles of the East and West Forks of the San Jacinto. Engineers recommended surveying the river after every major storm and dredging when necessary to reduce the risk of flooding. They even pinpointed where sediment would likely build up and pointed out that the West Fork was capturing 42% of all the sediment coming into the lake (see page 9). However, before Harvey, the City never dredged and rarely conducted surveys – decisions that haunt us today.

The mouth bar. Sand, in part from the mines, has almost totally blocked the West Fork where it meets Lake Houston. Unofficial before/after measurements show that as much as ten feet was deposited in this area during Harvey (five below water/five above).

Sedimentation: Danger that Can No Longer Be Ignored

One insidious aspect of sedimentation is its invisibility. Like gunk in pipes, you can’t see it – until water backs up and floods your home. That’s exactly what happened to thousands of homes during Harvey. The problem which had slowly built up for years, went from sub-acute to critical almost overnight because of the massive volume of sediment deposited during Harvey.

That brings us to our present impasse.

No News is Bad News

The City, FEMA, the Army Corps and the State have argued about this for at least six months. We thought they reached agreement in principle to remove the mouth bar three months ago. But still no official announcements have been made. Sadly, it didn’t have to come to this:

  • If only the City had followed the advice of the experts it hired…
  • If only the City had maintained its property…
  • If only the City could document how much Harvey contributed to the blockage…
  • If only the City had acted years ago to limit sand mining in the floodway of the river…
  • …we could have been working on the mouth bar already. Instead…

Problem Becoming Demonstrably Worse

In the 80 years since we started keeping records on the West Fork at US59, the river has crested over 50 feet 40 times – once every other year. But in the last 11 months, floods have reached that height SIX times – more than once every other month. We topped 50 feet in the latest flood just minutes ago. All resulted from relatively minor rains. This sudden surge in frequency did not result from global warming.

Is it all a statistical fluke? Wetter than usual weather? El Niño? Upstream development? Perhaps some of each. But one would have to be blind to dismiss the sediment buildup in the river. A delta is marching steadily downstream, creating blockages that back water up.

The West Fork just before Kingwood’s annexation in 1996 and after Harvey. Comparison shows advancing sediment buildups blocking the river.

The High Cost of Ignoring Expert Advice and Routine Maintenance

Harvey brought the high cost of ignoring expert advice and routine maintenance into sharp focus. The lack of a survey that could have been conducted in a few days is costing the City months of delays and potentially tens of millions of dollars in State and Federal assistance. This exposes hundreds of thousands of residents to needless flood risk and undermines property values.

What Needs to Happen

All of this underscores the need to budget for and maintain one’s own property. Drainage fees, which we just put a lock box around, should easily handle the City’s portion of dredging projects and surveys.

How do we break this impasse?

FEMA and the Corps need to restore the conveyance of the river that existed before Harvey. Estimate it using available evidence like aerial photos and satellite images. We’ll never have an exact figure. So quit using that as an excuse to put hundreds of thousands of people at risk. Let’s get started with dredging what we can. Legally.

In return, the City could commit to annual river surveys that document the status of the river before each hurricane season.

The City also could commit to a regular maintenance dredging program to keep sediment at a sub-acute level. The annual surveys will determine the exact amounts and frequencies.

The City could also throw its weight behind legislative efforts to move sand mines out of the floodway, where they contribute to levels of sedimentation far beyond natural rates.

I’m not a mediator and I’m not the Mayor, but that sounds like a fair compromise that can protect residents as well as officials on both sides of this negotiation.

Floods don’t happen as often as police or fire emergencies, but when they do, they affect hundreds of thousands of people in ways that can be just as life altering. This is a public safety issue. Let’s go. Reach an agreement, please!

These are my opinions on matters of public policy, protected by the First Amendment of the U.S. Constitution and the Anti-SLAPP statute of the Great State of Texas.

Posted by Bob Rehak on January 4, 2019

493 Days since Hurricane Harvey

Flooding and Floodplains in the Houston Area: Past, Present and Future

FEMA Flood Hazard Layer Viewer. Shows Humble-Kingwood-Atascocita-Corridor on West Fork of San Jacinto. Floodway (hatched), 100-year flood plain (aqua) and brown (500-year) flood plains are superimposed.

This Friday, from 7-9pm, Dr. William Dupre from the University of Houston Department of Earth and Atmospheric Sciences will conduct a  free Informational Workshop on flooding and flood plains sponsored by the Houston Geological Society. The event is free and open for the public.

Flooding in the Houston area over the last three years has caused residents and professionals alike to reconsider how we evaluate and respond to flood hazards in the region.
Dr. Dupre will discuss:
  • How watersheds and floodplains are defined and mapped
  • How individuals can obtain (and understand) information on local watersheds and floodplain maps
  • Recent floods, including how floods are measured and how flood frequency is calculated
  • How and why floods and floodplains in Houston have changed in the past, and are likely to change in the future
  • Possible approaches to reducing flood risk in the future.


Where:    Kingwood Community Center, 4102 Rustic Woods Dr, Kingwood, TX 77345

When:     Friday, August 24th, 7-9 PM

Speaker: Dr. William R. Dupre’, University of Houston, Dept. of Earth and Atmospheric Sciences

To reserve a seat: Please call the Houston Geological Society office (713) 463-9476 before 4 pm Thursday, August 23, or send your request to jajordan@hgs.org, and put “Kingwood Reservation” in the subject line.


Additional Information on Bond Proposal

The Harris County Flood Control District (HCFCD) Preliminary Draft of 2018 BOND PROPOSED PROJECTS is available at:the Harris County Flood Control District website.

The actual text of the Bond Proposal and Election can found at https://www.hcfcd.org/media/2855/bpl.pdf

This program is a community outreach effort by the Continuing Education Committee of the Houston Geological Society, the largest local geological society in the world.  The event is posted on their website.  Go to www.hgs.org; on the blue banner click on CALENDAR; on the Calendar page click on August 24.

Remember, the final day to vote for the flood bond is August 25, this Saturday, at your regular polling place. Please VOTE FOR it.

Posted by Bob Rehak on August 23, 2018

359 Days since Hurricane Harvey