Building 7,000 Homes Here Would Accelerate Subsidence

4/19/25 – Ryko, a development company, has announced plans to build 7,000 new homes in an environmentally sensitive, flood-prone area immediately west of Kingwood. Moreover, the area already experiences the highest subsidence in the north Houston region.

Residents in the area currently use groundwater. Assuming an average household size of 2.5 people, Ryko would add 17,500 new residents to the area. That could accelerate declines in groundwater levels and increase subsidence.

Reviewing the Subsidence District’s latest annual report revealed that the issue at this one reporting station is part of a larger problem. And the problem is very bad in southern Montgomery County.

Impacts of Subsidence

I have been posting about the issue for five-plus years. Subsidence happens too slowly to notice in most cases. But over time, it can be very disruptive:

• Excessive groundwater withdrawals can create bowls in the landscape that alter the gradient of rivers and streams. That can increase local flooding. For instance, when land at the county line sinks faster than land at the Lake Houston Dam, it tilts the lake toward the county line.
• Projected subsidence rates upstream could erase your freeboard factor (the height at which your home was built above the 100-year floodplain). That would increase your flood risk.
• Subsidence can also crack pipelines, storm sewers, and pavement.
• Uneven settling can cause your doors and windows to stick; crack foundations; split wallboard; and break tile.
• Near Galveston Bay, a whole subdivision even sank beneath the waves.
• Subsidence can also trigger long-dormant geologic faults.

For more examples of the impacts of subsidence in the north Houston area, visit StopOurSinking.com, a site developed by a Woodlands resident. There, subsidence has triggered faults and flooded multi-million-dollar homes through the “bowl effect.”

High Cost of a Little Flooding

Getting even an inch of water in your home can be very costly. According to FEMA, just 1 inch of floodwater in an average 2,000 square foot home can cost $10,000 to $20,000 to repair.

Higher-end finishes, such as wood floors, built-in cabinetry, granite, etc., can push those estimates past $25,000.

Why is one inch so expensive?

• Flooring usually needs to be completely replaced (carpet, wood, sometimes even tile if the water gets underneath).
• Baseboards and lower drywall (often up to 2 feet) usually must be cut out and replaced.
• Insulation in walls may need replacing if water wicks up.
• Cabinet bases and interior doors are often ruined.
• Appliances like washers, dryers, and even low-mounted electrical outlets might be affected.
• Mold prevention requires fast and sometimes professional drying and remediation.

In homes larger than 2,000 square feet, the cost would go up proportionately. For instance, FEMA estimates repair costs for a 3,000 square foot home to be 50% greater – in the $15,000 – $30,000+ range.

Disasters/accidents are rarely caused by one thing. They usually result from a combination of factors eroding margins of safety.

For instance, the risk of a driving accident increases when you’re tired, it’s dark and the pavement is wet. That’s why it’s important to pay attention to little things that can degrade your margin of safety. They may not be so little in the next big storm.

Posted by Bob Rehak on 4/19/2025

2790 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.