First the background: In Texas, near the Dallas area there are two major reservoirs, Cedar Creek Reservoir and Richland Chambers Reservoir. Both of these were created by damming different forks (headwaters) of the Trinity River. About 150 miles downstream from these reservoirs lies Lake Livingston, also on the Trinity River.
Now the question: I am trying to find info on what would be the projected impact to Lake Livingston should one of the upstream dams fail. I am seeking information as to how long it would take flood waters to reach Lake Livingston and if Lake Livingston dam would have time to release adequate water in advance. In the US, when a dam is built is there a ‘flood plan’ or ‘contingency plan’ of sort that would show areas downstream which would likely be damaged if the dam should fail? I am not sure what such a plan would be called, however I have looked at the US Army Corps of Engineers website and the Trinity River Authority website and I have found nothing. Any suggestion as to where can I find this info? Thanks!
I have no real knowledge here, but it seems improbable that a downstream dam could safely release enough water.
A failure would be most likely when water levels are high, which means that the downstream dam would have to release an amount of water comparable to what it will receive in the coming flood (under the somewhat dubious assumption that it’s capable of that rate of release). And that’s pretty well guaranteed to be bad news for anyone further downstream.
I can’t help with your specific case however many dams have airspace for flood mitigation so they might be fifty percent full at one hundred percent capacity, if this still doesn’t contain a flood then you often have a sacrificial embankment designed to erode away and save the dam from total collapse.
What you’re looking for is called a “dam failure inundation hazard map”. There should be one for each dam in question, prepared according to Corps of Engineers guidelines. They used to be easy to find, until the PTB decided that they might inspire terrorists to try to blowup a dam. But they’re not secret; if you can’t find it online, try the local city or county planning agencies (Do they have planning agencies in Texas?), or the agency that is actually in charge of operating the dams.
There has been a subtle concern for decades with all of the dams along the Columbia River in the Pacific Northwest. A significant earthquake damaging just one dam (let alone damaging a dam upstream from one or more other dams) could have catastrophic consequences. Since 9/11, the concern has moved from subtle to very active. Perhaps not the equivalent to the Lake Missoula floods but who cares at that point.
For a fictional look at just this type of situation, written by someone who works for the Bureau of Reclamation (who manages water resources and dams), check out the novel Wet Desert.
It deals with just your question: what happens to a downstream dam when an upstream fails, and what can be done to save the downstream dam.
Here’s the Trinity River Basin Master Plan. (warning: PDF) While it won’t specifically answer your question, it’s loaded with links to other studies, river authorities, etc.
One thing I did notice
So it looks like there’s a substantial portion of unprotected floodplain upstream of Lake Livingston. In the event of a catastrophic deluge, that might be bad news for the corridor in general, but good news for the dam as the water spreads out.
Thanks everyone for the responses! Looks like there is lots of data out there! Just fyi this whole subject came up due to the number of recent earthquakes around the Dallas areas which some believe could be caused by oil fracking…which is a different argument altogether. Thanks again
You’ll want to see the Emergency Action Plan for the Lake Livingston Dam. That can be found at FERC’s web site, and provided you have the requisite credentials to view the plan, will probably answer a lot of your questions.
Alternately, ask someone at the Texas Department of Environmental Quality’s Dam Safety Program if they can help you with your questions.
Lake Livingston’s dam has had some issues, notably with erosion caused by high winds from Hurricane Rita.