All quiet on the western front—West Houston, that is. Looking down into the Barker Reservoir from the edge of a flat-topped earthen wall of a dam, one spots deer and egrets, as well as stripes of freshly exposed wood on trees, telltale signs of industrious beavers. The green expanse before us feels like a nature park, even as nearby we hear the steady hum of 500 cubic feet of water rushing through a conduit each second. For a moment, we forget that if Houston ever faces disaster on a grand scale, the Barker dam—as well as the one in Addicks—may well be ground zero for the city’s destruction.

Constructed in the 1940s near the modern-day intersection of I-10 and Highway 6, the dams were built in response to a pair of devastating floods in 1929 and 1935, the latter of which killed eight people and caused extensive damage after 17 inches of rain drenched the city.

The Army Corps of Engineers estimates that over the years the Addicks and Barker reservoirs have saved Houston from $8 billion in flood damage. Yet the task of protecting the city from flooding has grown ever more difficult as the areas upstream of the dams have become more developed and more water runs off into waterways rather than being absorbed into the soil. And then there’s all the development downstream, which creates its own runoff, limiting how much water can be released from the dams into Buffalo Bayou. The upshot? During extreme rain events, both reservoirs will fill more quickly and be expected to hold more water for longer periods of time.

“It’s all applying additional pressures to the dams,” says Richard K. Long, who supervises the Addicks and Barker dams’ day-to-day operations for the Corps.

An aerial shot of Addicks Dam during recent a flooding event. Image: Courtesy of U.S. Army Corps of Engineers Galveston District

That pressure became obvious after a heavy storm in 2009 dumped 8 to 10 inches of rain on West Houston. With the water in the reservoirs at record levels, engineers noticed water seeping through voids, or gaps, under the dams’ conduits, which control how much water is released into Buffalo Bayou.

The prospect of failure is truly terrifying. If either dam were to fail during or after a major storm, floodwaters rising from Buffalo Bayou could potentially submerge homes and businesses in the Memorial area, downtown, the Medical Center and beyond.

That same year, the Addicks and Barker dams were rated “extremely high risk” by the Army Corps of Engineers—although the organization also noted that the dams were not “in imminent danger of failing.” Confused? After Hurricane Katrina, the Corps changed the way it evaluated infrastructure, assessing not only structural risks but also the potential loss of life and property from a failure. How the formula is computed to arrive at this rating, and to what degree it is based on existing problems, is an area in which the Corps has been frustratingly vague,

Even so, the designation has garnered national attention. Vice magazine, in a hard-hitting look at America’s infrastructure problems last February, called Houston’s two major dams one of seven American projects “on the verge of collapse.” The prospect of failure is truly terrifying. If either dam were to fail during or after a major storm, floodwaters rising from Buffalo Bayou could potentially submerge homes and businesses in the Memorial area, downtown, the Medical Center and beyond. For his part, however, Long adamantly insists that the dams’ low ratings have more to do with potential consequences than structural problems.

In any event, the Addicks and Barker dams are now “on the top of the money heap” when it comes to federal funding for improvement. Since 2009, the Corps has spent more than $4.4 million on interim fixes like filling in the leaking voids. This fall they are expected to begin building new water control outlets, part of a three-year project that will cost between $75 and $100 million. These new conduits will be surrounded by man-made materials instead of Houston’s sandy soil to create a perfect seal, and a second set of gates will be added to provide yet another layer of protection when the reservoirs are holding back a large volume of water.

As the growth of Houston’s far western suburbs continues apace, the reservoirs will likely spend more and more time as bodies of water and less as green space. But it’s nothing the improved dams won’t be able to handle, Long says.

“It’s a good facility for what it’s designed for. It’s being taxed more and more all the time, but I think it’s got another 70 years in it. That’s more than I’ve got in me.”