News - Reduce Flooding

Two New MoCo Developments Will Total Almost 3,400 Acres, Have No Detention Ponds

Two new developments in Montgomery County, Audubon in Magnolia and Country Colony in Porter, will have no detention ponds. The two developments total almost 3,400 acres. During heavy rainfalls, they will dump their floodwater directly into local streams.

How Do They Get Away With That?

Sixteen months ago, on the second anniversary of Harvey, Montgomery County commissioners voted to leave open a loophole that lets developers avoid detention pond requirements. They said they would revisit the issue after the San Jacinto River Basin Study was completed. Even though partners shared study results with the public last August, MoCo commissioners have still not revisited the loophole called a “flood routing study,” also known as hydrograph timing.

The commissioners expressed concern in their 2019 meeting about placing economic hardships on developers. Residents complained about the economic hardships caused by flooding. The developers won.

Theory and Problems with Flood Routing Studies

The idea behind flood routing is simple. If you can show you can get your floodwater to the river faster than a flood’s peak arrives, theoretically, you’re not adding to the peak. Therefore, theoretically, you’re not making flooding worse.

However, engineers and hydrologists point out several flaws with this “beat the peak” theory.

Flood-routing studies don’t consider the cumulative effects of other developments.
They are almost always based on outdated hydrologic models.
They assume “ideal” storm conditions.

“If you start with a brand new hydrologic model,” said one county engineer, “the modeling a developer does could theoretically be accurate. But his/her runoff changes the model. That runoff rarely gets incorporated into the model that the next developer uses.”

And, of course, if everybody rushes floodwater to a river during a flood, that’s the exact opposite of what you want. Holding water back in detention and retention ponds is the best way to reduce flooding.

The two new developments in MoCo exploit this routing-study loophole to avoid the cost of building detention ponds.

Audubon in Magnolia

The first, called Audubon Magnolia will contain 5,000 homes at buildout. It occupies 3,300 acres that drain into Mill Creek, Spring Creek and then the West Fork San Jacinto.

Here is the entire 186-page Drainage Impact Analysis for section one. It also shows project plans and location.

*From Audubon’s drainage impact analysis. Note school being placed at edge of floodplain…before new floodplain maps are redrawn based on Atlas-14.*

Section 3.1 of the Impact Analysis includes a description of the flood routing study and concludes, “Therefore, the increased flows are able to exit into Mill Creek before the flow from the bulk of the upper drainage basin arrives at the mouth of the stream.”

Correspondence with Montgomery County officials at the front of the document shows their concerns: use of pre-Atlas 14 data; impact on wetlands; building in floodplain; roughness co-efficients used to model speed of water over various terrains; and impact on water surface elevations.

Clearly, the floodplain administrator had major concerns about use of pre-Atlas 14 rainfall data. However, the developer was grandfathered based on the date of the original permit application.

Montgomery County’s new Atlas 14 standards increased the total for a 24-hour, hundred-year rain by 4 inches. The Flood Plain administrator encouraged the developer to model the higher rainfall totals and build to higher elevations. Why? To ensure the likelihood of compliance for those homes in the future.

These documents, dated 2019, are the latest available from Montgomery County. The county engineer’s office indicated that no detention ponds are being planned by the developer or demanded by the County.

Country Colony in Porter

The second development, Country Colony, lies just north of the Harris County/Montgomery County line at the end of West Lake Houston Parkway. Country Colony occupies approximately 80 acres immediately west of the Triple PG sand mine.

*Note county line at southern edge of development. Also note how some of the lots are actually in the floodplain of White Oak Creek.*

*Country Colony. Taken December 7, 2020, looking east toward Triple PG Sand Mine in background.*

No detention ponds here either! A big heads up to the people downstream in Walden Woods, Woodstream Forest and beyond.

Posted by Bob Rehak on 12/12/2020

1201 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.

Daredevils at Triple PG Mine Continue to Push Safety Envelope

Two daredevil sand mining companies, Triple PG Sand Development, LLC and Texas Concrete, have stepped up their efforts to mine sand between pipelines that carry natural gas and highly volatile liquids.

AG Lawsuit Filed in 2019

In October of last year, the Texas Attorney General sued the Triple PG mine in Porter for up to $1 million on behalf of the Texas Commission on Environmental Quality (TCEQ). The original petition in the case cited repeated breaches in the mine’s dikes over a period of several years that let process water and sediment from the mine escape into the headwaters of Lake Houston. Lake Houston supplies drinking water for approximately two million people.

Days after the AG filed the suit, the mine’s owner, Dr. Prabhakar R. Guniganti, a cardiologist from Nacogdoches, tried to shuffle ownership of the mine through a series of trusts controlled by his family. In June of this year, the AG filed an amended petition, naming all the trusts and their officers (both individually and as directors) as additional defendants.

In that amended petition, we learned that a new operator started managing the mine in May of this year. However, Guniganti still owns it, according to the Montgomery County Appraisal District. The new operator is Texas Concrete, the same company that TCEQ fined in Plum Grove on the East Fork – for multiple breaches and other violations.

Both the TCEQ and AG’s office have declined to comment on ongoing legal matters relating to the Triple PG operation. However, while flying over the mine on Monday this week, I saw something very disturbing.

Mining Between Pipeline Corridors

Kinder Morgan has an easement for a natural gas pipeline through the mine. You can see the pipeline path on the left in the photo below. Their pipeline was exposed during Harvey by erosion and had to be buried deeper. Luckily, no explosions or fires resulted.

*Looking NW. Mining between pipelines at the Triple PG mine in Porter.* *Natural gas line on left; HVL lines in utility corridor at top of frame.*

Additional pipelines carrying highly volatile liquids run through the utility corridor at the top of the frame. LMI exposed those same pipelines further northwest when it mined on both sides of them. Then erosion ate the sand out from under them.

Now, Triple PG and Texas Concrete are mining sand from between the pipelines. This will increase the potential for erosion in future storms. That could expose pipelines and potentially lead to pipeline ruptures, spills, and/or explosions.

*Looking west. Removing additional ground cover makes the pipelines on either side more susceptible to erosion and exposure during floods.*

*Looking south. Notice on right how mine has run heavy equipment across both pipeline corridors, a dangerous practice according to pipeline engineers.*

To adapt a phrase about pilots from the aviation industry, “There are old miners and bold miners.” Those daredevils at Triple PG sure are Bold. With a capital B. As in Boom.

Posted by Bob Rehak on 12/11/2020

1200 Days since Hurricane Harvey

Rivers of Mud: Largest Development in Liberty County Openly Flaunts Drainage Regulations

To prevent erosion that sends sediment downstream, current Liberty County Drainage Regulations specify that developers must:

Plant grass on the banks of ditches
Construct backslope interceptor swales

But aerial photos taken this week show that drainage ditches in the massive Colony Ridge development rarely have grass on their banks. And while criss-crossing the development in a helicopter on Monday, December 7, 2020, I did not see one backslope interceptor swale. This, DESPITE Colony Ridge being the largest development in Liberty County. Or maybe it’s BECAUSE Colony Ridge is the largest development in the county. Perhaps they think they can flaunt regulations.

Colony Ridge is even larger than any of the cities in Liberty County – by far. You would think that would make violations more visible. But apparently, it makes them less so. Much to the detriment of downstream communities.

What Ditches Should Look Like If Regulations Were Followed

Regs in Liberty County are similar to those in Harris County. Here’s a photo of a drainage ditch in Harris. It shows both grass and interceptor swales in use and how they help prevent erosion. Note the swales behind the shoulders of the ditch. Also notice the concrete structures that help pipe rainwater from the swales to the bottom of the ditch. They prevent water from washing down the ditch slopes and causing erosion. Had the developer followed the regs, which represent best practices, his ditches should look like the one below.

*Backslope interceptor swales with drain pipes leading to bottom of ditch help prevent erosion. Photographed in Humble in Harris County.*

Erosion Control as Practiced in Colony Ridge/Liberty County

Now, compare that to the following 18 photos. I took all of them over Colony Ridge on Monday. Some show newly developing areas subject to the latest regulations adopted in 2019. Others show areas already developed under regulations from 2004. The older regs required grass, but no interceptor swales. The newer regs require both. No attempt has been made to bring the older ditches up to newer standards despite obvious erosion problems.

Note how the developer has a habit of piling dirt next to the ditches. The TCEQ cited the developer for that practice earlier this year because dirt could wash back into ditches during rains. However, the developer obviously doesn’t fear the TCEQ. He’s still doing it. On a grand scale.

*Ditch on right has grass on banks but no backslope interceptor swales.* *Note dirt piled on banks and how it’s already eroding into ditch.*

*No grass. No swales. Piles of dirt* *on the ditch’s shoulders.*

*Again. No grass. No swales. More dirt on shoulders.*

*Some weeds, but no grass. No swales. And a river of mud.*

*Rio de Lodo*. “Lodo” translates to mud, sludge or mire in English.

*This ditch has more corrugations than a cardboard factory thanks to the total absence of erosion-control measures.*

*Ditch in new area without erosion control measures near Highway 99 extension (in upper left of frame*). *Note eroded sediment already moving down the ditch.* *See close-up detail below.* *Regulations say that grass should be planted on ditch shoulders immediately after ditch construction.*

*Detail from upper right of previous photo.*

*Note erosion in ditch in foreground and other ditch T-ing into it.*

*Pipe from resident’s home enters ditch at top, accelerating erosion. Enlargement shows brownish liquid dripping from pipe*.

*Even newer stick-built homes on left don’t get erosion protection.*

*Note a wheelbarrow next to the man. Perhaps he’s trying to excavate blockages in the ditch* *behind his house.*

*Note how erosion has taken dirt from under fences.* *Better keep the dog on a leash!*

*The mud in ditches has made them playgrounds for ATVs, further contributing to erosion.*

*The mother of all eroding ditches in Colony Ridge.* *(BTW, note the absence of fire hydrants on the long street left of ditch.)*

*Erosion has created a training ground for mountain goats in Colony Ridge.*

Externalizing Development Costs

All this erosion (from approximately 12-13,000 acres) eventually winds up in the East Fork of the San Jacinto and Lake Houston. There, taxpayers must pay to have it dredged and filtered out of the water supply.

*Downstream from Colony Ridge. East Fork Mouth Bar after Imelda*. *After depth in this reach is now 3 feet. It was 18 feet before Harvey.*

*New Northeast Water Purification Plant at Lake Houston will cost taxpayers $1.4 billion.*

The East Fork Mouth bar forms a sediment dam that also has contributed to the flooding of more than a thousand homes.

Meanwhile, the developers cheaping it out are counting their change all the way to the bank.

Posted by Bob Rehak on 12/10/2020

1199 Days since Hurricane Harvey and 448 since Imelda