Bayou City

New App Shows How Houston Has Sunk Over Time

Flooding on Allen Parkway last year.
Flooding on Allen Parkway last year. Photo by Leif Reigstad

Houston likely won’t be sinking into the Gulf of Mexico anytime soon, but if residents ever want to see just how close it is getting, or track areas to beware of in the future, now there’s a handy resource online.

A new web tool from the U.S. Geological Survey tracks 40 years of data to provide a complete picture of the city's sinking, and recovering, groundwater levels over the past decades – as well as how regulatory actions have helped some areas recover. Much of the information is nothing new, but it gives engineers, policymakers and regular citizens a better understanding of problems they might face now and in the future.

Houston already sits in a precarious position as one of the country's coastal cities, where rising sea levels combine dangerously with subsidence, or the depression of ground levels.

“When water levels decline, subsidence occurs on aquifers and that can contribute to flooding and infrastructure damage,” explained Mike Turco, a general manager with the Harris-County and Fort Bend Subsidence districts. “Our job is to minimize the aquifer water level decline.”

The USGS has provided data to the subsidence district since 1975, but this is the first time citizens can access the information to create a complete picture of groundwater levels in the city. The online tool shows much of what Turco expected: In areas where regulatory actions were taken, as around the Houston Ship Canal, significant improvements have occurred.

In 1977, water levels around the canal had sunk to as much as 300 feet because of the reliance on groundwater as a source of water. Lower water levels lead to ground sinking, meaning more flooding and damage to the area. When the district called for a move toward other water resources, those levels began to rise. Today they are closer to 100 feet.

This data is invaluable to Turco and the district as they aim to reduce and even stop subsidence in the city. Using water demand and population growth, they can determine where problem areas may occur and make changes accordingly. The $381 million Luce Bayou Transfer Project, which is transferring water from the Trinity River to Lake Houston to meet increased demand for surface water in the region, is an example of the kind of infrastructure projects based on the district's regulatory plans.

The online tool is meant more for engineers than average citizens, but a quick exploration through the app can reveal some interesting facts. These include how Galveston County and southeastern Harris County has benefited as it shifts from underground to alternative water sources, while up north, where authorities are still implementing changes, levels are still low.

“One thing to keep in mind is that a one-year change doesn't mean much for us,” Turco said. “We’re looking at long-term changes.”

Here's hoping they find the good kind.
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Joseph Fanelli is a reporting fellow at the Houston Press with an interest in education, crime and eccentric people everywhere.