Enclave Construction Stopped While Engineers Review Drainage

6/2/25 – Construction has stopped, at least temporarily, at the Enclave, a new 11-acre residential development adjacent to the Northpark expansion project in Montgomery County.

Both Montgomery County and the City of Houston have asked engineers to review the drainage plans, which showed the development’s detention basin overflowing into the only evacuation route for 78,000 people during extreme weather events.

HNTB, the engineer for the Northpark Expansion project, is going to conduct a peer review of EHRA plans for the Enclave’s drainage. They need to hurry.

Detention Basin Already Dug Out

Photographs taken over the weekend and today show that construction crews have already dug out the proposed detention basin. And they are starting to install pipes and junction boxes for drainage.

However, late in the day, I received word from two independent sources that both the City and Montgomery County stopped construction for the review of engineering documents.

Sketchy Update to Old Plans

The new development is technically part of Kings Mill, which had its drainage plans approved more than a decade ago. But between the approval of the initial drainage plans and the start of Enclave construction, more than a decade passed. And during that time, Montgomery County and the City of Houston both adopted Atlas 14 rainfall statistics. Atlas 14 statistics are 33% to 40% higher than those used for the rest of Kings Mill.

And Kings Mill is more than 20 times larger than the Enclave. That means there’s a helluva lot more stormwater being funneled toward the Kingwood Diversion Ditch than the people who designed the ditch expected.

The Enclave’s detention basin would have supposedly “held” the incremental volume of rainfall dictated by the new higher rainfall standards – but only for 11 acres, not 240.

Plus there were inconsistencies between the initial and current plans, including the size of the acreage involved for the Enclave.

Concerns about Capacity, Its Impact and Inconsistencies

Several other things happened after the initial drainage study.

• The developer’s plans raised concerns about where Enclave overflow will go during an extreme event. (See construction diagram above.)
• The Northpark Expansion project started. A major goal: to create an all-weather evacuation route when Hamblen Road, Kingwood Drive and Mills Branch Road are cut off by high water.
• Hurricane Harvey flooded hundreds of homes adjacent to the Kingwood Diversion Ditch, raising unaddressed concerns about the capacity of the receiving ditch.
• Construction plans showed inconsistencies between the initial drainage impact analysis and the recent update for the Enclave’s eleven acres.
• The developer claims it can build ten homes to the acre with only 55% impervious cover, an extremely ambitious goal.

Photos Show Drainage Route to Kingwood Diversion Ditch

I took the photos below last weekend. They show the new Enclave development and the path that stormwater will take on its way to the Kingwood Diversion Ditch, which already has capacity problems of its own.

Hundreds of homes have flooded because of the ditch’s diminishing capacity to accommodate additional growth as new subdivisions have been bolted on.

Harris County Flood Control is currently conducting a search for engineering companies to make recommendations for improving the ditch. But it could take years to find the money to construct any recommendations for conveyance improvements that come out of the study.

So MoCo and the City want to make sure they get this right. The photos below show how all the drainage will connect.

Once contractors have drain pipes and culverts in the ground, start pouring concrete for streets, and building homes, it will be very difficult to make any changes – if they are necessary.

So, it’s good that construction has been paused now for peer review.

Posted by Bob Rehak on 6/2/2025

2834 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.

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