That is part of the design of these facilities
Houston, Texas (Vocus) September 12, 2008
Two reservoirs stand ready this morning to receive the predicted five to 15 inches of rainfall from Hurricane Ike, says Richard Long, operations manager for the Addicks and Barker Dams and Reservoirs, which fall under the Galveston District, Army Corps of Engineers. These reservoirs, or dry detention basins, are part of the Buffalo Bayou and Tributaries Flood Control Project. "As of this morning, we have full capacity availability in both basins."
That's important, because the two giant retention reservoirs are part of a flood risk management system that helps to manage flood waters that may threaten downtown Houston and areas along Buffalo Bayou. Both reservoirs are capable of capturing rains associated with a 100-year storm event (an event that has about a one percent chance of happening in any given year).
If Hurricane Ike turns out to be such an event, the reservoirs should hold, Long said. "Addicks can hold a 20-inch rain, which is more than Ike is predicted to give us. Barker can hold 15 inches, and Ike could produce that much rain."
The bigger question, Long says, is the timing of weather events preceding and following a big storm. "These reservoirs are very close to the areas they were built to protect," he explained. "We can hold storm water, and then begin to release it as water downstream of the two dams clears out of the Buffalo Bayou. Travel time for water leaving the dam's release point through downtown Houston is only 30 hours. That doesn't always give us the five-day margin to hold flood water back that some dams enjoy. These facilities are effective for most single events, but a series of heavy rainfalls could bring about water levels that would bring about flooding outside the basins. In a crunch, this could mean that we would be forced to allow flooding to happen upstream of the facilities."
Colonel David C. Weston, Galveston District commander, said that the Corps would, as always, be carefully monitoring the two dams and managing operations so as to minimize risks of flooding both downstream and upstream. "We urge people to stay alert to weather reports. We work with county emergency managers for both Harris and Fort Bend Counties. In the event of any flood emergency, people should heed any warnings or evacuation orders issued by those counties."
During the days and weeks following the passage of Hurricane Ike, people may see the reservoirs holding water, and roads and recreation areas around them may be flooded. "That is part of the design of these facilities," Weston said. "That flooding is holding on to some or all of the rain that fell in the 260-square-mile basin upstream of the dams. It takes time to clear it out of the system."
martha.j.cenkci @ usace.army.mil
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