Hulking framework guards the Houston an ar against storms – yet it’s not always enough. And also climate change promises to check our fabricated defenses further.

You are watching: How much of houston is flooded

By Emily Foxhall, Yoli Martinez, Ken Ellis, note Mulligan, Chronicle Digital Team | July 20, 2021 | Updated: July 20, 2021 4:50 PM


Living in Houston way living through the threat of significant flooding. Hurricane Harvey and other storms have presented how vulnerable the an ar is to being swamped. That risk remains, even with infrastructure to reduce it.

For now, two enormous reservoirs west that downtown Houston hold ago rainfall. A seawall in Galveston buffers storm surge indigenous the Gulf. Bayous and also man-made networks drain water native the region. Levees protect suburban neighborhoods, and also lakes supposed to be resources for drinking water dual as places to store water.

But this defenses can fall short. Take into consideration Hurricane Ike, i beg your pardon wiped away dwellings in 2008 together it driven at least 10 feet of water over lot of Bolivar Peninsula. Or Harvey, i m sorry in 2017 submarine the an ar with one astounding 60-plus inch of rain.

Climate change science tells united state to brace because that worse. Heavy rainfall will likely be more common, hurricanes will likely be stronger and sea level will most likely keep rising.


Potential flood Map

What ends up under water doesn’t always line up through flood maps produced by FEMA, but the maps have the right to be guidelines for residents and also homeowners. Listed below you’ll uncover what"s supposed to it is in inundated in a 100-year flood, which has a 1-percent chance of arising in a year, and a 500-year flood, which has a 0.2 percent chance of developing in a year.


Flood Plain
Floodway
100-year
500-year

With an ext and an ext dangerous storms ahead, an knowledge of how your home is safeguarded – and how it’s vulnerable – is crucial knowledge because that every Houston resident. Here’s an explanation the each significant flood mitigation system, and also what has been proposed, or not, to strengthen it.


reservoirs


What's there now



The Addicks and also Barker dams and also reservoirs space the city’s main defenses against flooding, holding ago rain that drops west and northwest of town. The U.S. Military Corps of engineers dug the end the land and also built the 2 U-shaped, earthen barriers around it in the 1940s, as soon as the area to be still prairie.

Today, the reservoirs room surrounded by urban sprawl. They’re generally dry, definition they’re basically large parks when it’s no storming. Civilization walk and jog alongside the grassy dams. Buffalo Bayou and its tributaries meander with the reservoirs. Homes sit in both.


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Each dam has actually two new sets of three gates. They’re usually open enough to allow water to flow through, heading down Buffalo Bayou and also out to the delivery channel.
When the entrances shut, the reservoirs start to hold water. This help Buffalo Bayou have an ext room downstream for water that drops over the city.
Staff can later open up the gates after a storm passes to drainpipe water gradually from the reservoirs.
The dams are additionally designed v reinforced end to enable water come flow about the backs if the reservoirs begin to gain too full.

Limitations

When come close the dams’ entrances can be a complex, high-stakes calculation: If they shut as well late, the bayou could not have sufficient capacity in main Houston to organize water. If lock shut also soon, the reservoirs can fill also fast.

For added protection, the ends of the dams that slope towards the floor are developed with various material. These “emergency spillways” allow water flow around back and also over the ends. Yet if water overtops the dam itself, it would certainly likely cause catastrophe, releasing massive quantities of water towards downtown.

Looking ahead

The military Corps set up the brand-new gates in 2020 and also updated the networks where the water operation out. But far-reaching issues remain. The reservoirs filled for this reason much during Harvey that adjacent homes flooded. Homes downstream additionally flooded as the Corps exit water to try to keep water indigenous going over the spillways.

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Engineers decades ago proposed building a 3rd reservoir. The still hasn’t happened. A new federal plan is looking in ~ the idea, and widening and also deepening Buffalo Bayou. Environmental advocates have pushed back versus these proposals.


Resource


Submit input on these plans here.Check the height of water in Barker reservoir here. And also in Addicks here. (Water will the finish of the Barker dam in ~ 104 feet and Addicks in ~ 108 feet.)