Enclave Construction Stopped While Engineers Review Drainage
6/4/25 Update: Construction has not yet stopped and it may not. It continues as City and County Authorities try to set up a meeting to review drainage plans with engineers.
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 between 5/31 and 6/2/25 show that construction crews have already excavated the proposed detention basin. And they are starting to install pipes and junction boxes for drainage.
However, I have received word that both the City and Montgomery County have asked for construction to be paused for a new independent peer review of the development’s drainage plans.
Partial Update to Outdated Drainage Plans
The new development is technically part of Kings Mill, which had its drainage plans approved in 2012. But after Harvey in 2018, Montgomery County and the City of Houston both adopted Atlas 14 rainfall probability statistics, which are 33% higher than those used to design virtually all of Kings Mill’s infrastructure.
That means Kings Mill – which is 20 times larger than the Northpark Enclave – funnels much more stormwater toward the Kingwood Diversion Ditch than it was designed to handle.
Yet Enclave engineers designed its detention basin to hold only the difference between the old and new rainfall statistics. And only for 11 acres, not all 240.
Concerns about Capacity, Its Impact and Inconsistencies
Several other things have happened since approval of the 2012 drainage study.
- 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.
- The developer’s plans raised concerns about where Enclave overflow will go during an extreme event. (See construction diagram above.)
- Hurricane Harvey flooded hundreds of homes adjacent to the Kingwood Diversion Ditch, raising as-yet-unaddressed concerns about the capacity of the receiving ditch.
- Construction plans showed inconsistencies between the initial drainage impact analysis and today, including the size of the Enclave.
- 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
Photos below show the new Northpark 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 as insufficiently mitigated new subdivisions began draining into it.
Harris County Flood Control District (HCFCD) has completed its preliminary engineering review of the Diversion Ditch. HCFCD is now in the process of selecting an engineering company to make final recommendations for improving the ditch. But it could take years to find the money to construct any recommendations 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 and start pouring concrete, it will be very difficult to make any changes. 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.
