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Damming News From Washington State
Trax3001BBS writes "A 65-foot (20-meter) crack has been found in Wanapum Dam, one of the major dams along the Columbia River in southern Washington. Water levels are being lowered to both reduce water pressure and give the inspectors access to the area. 'Earlier this week, an engineer noticed a slight irregular "bowing" above the spillway gates near where cars can drive across the dam. When divers finally took a look under water they found a 2-inch-wide crack that stretched for 65 feet along the base of one of the dam's spillway piers.' The article goes on to say, 'Even if the dam doesn't fail, the significance of the damage is likely to require extensive repairs and that, too, could impact the entire Columbia River system. "All these dams coordinate to generate energy on a regional scope," Stedwick said. "If Wanapum is impacted, that has impacts on dams upstream as well as below." Upstream dams would be required to handle more water; there's only one lower dam (Priest Rapids). After that is the last free flowing section of the Columbia river. I've taken walks along that section, and I've seen it deviate (higher or lower) by amazing amount of water, so it can handle the changing flow rate. Making this situation more complex, a large group of people would like that particular dam removed, as well as the one above and below it (think of the fish!). On top of that, after the Priest Rapids dam (downstream from Wanapum Dam) is the Hanford Nuclear Reservation, once a site for Plutonium production. Either of these issues could generate a ton of attention. Personally, I'd like to give the engineer that noticed a slight irregular 'bowing' my congratulations."
If there is only one dam below Wanapum, this will be easy. But don't miss an opportunity to throw in a totally irrelevant mention of the Hanford nuclear weapons complex - you know, that place that itself gets irrelevantly dragged into any discussion of commercial nuclear power.
William Mulholland didn't take action when the St. Francis Dam performed similarly, and after his inspection, killed up to 600 people twelve hours after his inspection.
Kriston
That last free-flowing stretch of the Columbia River that the OP mentions is also the last stretch of Columbia River that maintains spawning habitat. It also accounts for a very large portion of the salmon that return through the Columbia River estuary every year. If removing this dam would open up more spawning habitat, this would not be a bad thing.
Meanwhile, the RAF categorically denies that an Avro Lancaster was seen near the dam earlier that day.
Hail Eris, full of mischief...
E pluribus sanguinem
Water doesn't "soften" concrete. H2O is molecularly bound into its structure and is a necessary part of maintaining the strength of concrete. Water invading earthen dams, on the other hand, is a more serious problem.
I am becoming gerund, destroyer of verbs.
I'm sure glad they caught it. China has a similar series of hydroelectric dams. A failure caused a domino effect and when the Banquai dam failed it killed 200,000 people. I know TFA says the failure of this one dam wouldn't kill that many people, but that assumes the sudden tidal-wave-like flood doesn't effect the downstream dams. A domino failure on the Columbia river would be a catastrophe.
This is the problem with Hydro power. This is why we should go 100% solar and not use electricity at night. We can't safely use Hydro, it's too dangerous, the pressure levels and engineering is too dangerous and a single mistake could kill an entire ecosystem.
Think of the children down river from this dam!
If you have any incandescent bulbs, _YOU'RE_ to blame as well.
-Francis Candlemaker
-Malakai
A Dragon Lives in my Garage
There are 5 dams down stream of wanapum, 1 above the free flowing hanford reach and 4 dams below that. River "operations" involve a complicated coordination of all the dams and reservoirs to provide adequate flow for fish and year-round power generation. It is an interesting engineering problem - hacking a river. There is also a computer angle here in that several data centers are located in Grant County (which owns the generation rights) to take advantage of the cheap reliable power. Presumably those data centers are watching this closely. Power rates for everyone in the county will rise if they have less power to sell or if they have to buy power from outside the county. The system is dependent upon storage for of moving water down stream the river is very interesting in that water flowing through one dam
Unless the damn was built after using 3d rendered models and ran through thousands of simulations then it isn't "tech". It took no math or science to build the Erie Canal, the Hoover Dam or the Panama Canal. In seriousness this is a better story on the site than a story about outstanding student loan debt. The engineering in projects like this and what it will take to fix it requires the same skills as people who design realistic game environments and physics simulators, etc. Many facets all come into play. Anyone who doesn't see this as "news for nerds" should probably go visit the Hoover Dam or tour an aircraft carrier.
It took no math or science to build the Erie Canal, the Hoover Dam or the Panama Canal.
Unfortunately, I had to read the rest of your post three times to make sure you weren't seriously claiming this. It's amazing the number of self-proclaimed nerds who don't seem to understand that technology actually does predate computers.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
The steel is bathed in moisture for decades without weakening. Concrete hardens and is stronger under water. Water cracks concrete via the thaw freeze cycle. Water enters the void, freezes, expands, widens the void. But a 60 foot long crack suggests something shifted under the damn.
The data centers in Quincy are quite large. Microsoft has a major facility, which is undergoing expansion. So does Yahoo, Intuit, Dell, and Sabey. These are major components of the tax base for the town of Quincy and elsewhere in Grant County. The data centers are highly resilient to power loss, with on-site diesel generators, 24x7 staffing, and all the other protections you'd expect. But prolonged use of the generators, if it becomes necessary, could exceed the permitted run time and accompanying pollution the facilities are allowed. Most likely, power from the other dams the Grant County PUD operates (or elsewhere on the regional power grid) could be routed to the data centers.
There are some other huge electricity consumers in the county. It's the world headquarters of a company that makes photovoltaic components, and also several food processors (all those potatoes from eastern Washington gotta be processed and cooked!). Industrial users might be able to turn down their power usage if there is a regional shortage, but data centers tend to operate at fairly stable 24x7 consumption levels. Major companies like those listed above have redundant facilities, and can shunt processing to other centers if required.
Site selection for major electricity consumers, including data centers, is a fascinating topic. The State of Washington has had various tax incentives to help businesses to choose to build facilities there. Electricity costs are among the lowest in the nation (under 3 cents/kWh for industrial customers). Plus, it makes extensive use of renewable sources, particularly hydroelectric (i.e., dams) and wind energy. Oregon has a similar story to tell, with their own rivers, dams, tax breaks, etc., and is part of why Amazon elected to put a huge facility there.
Don't worry - the only thing downstream from this dam is Portland.
#DeleteChrome
It has nothing to do with the moisture. It has to do with pressure. A dam represents a boundary layer between high pressure (behind the dam) and low pressure (air in front of the dam. An intact dam's structure distributes those stresses evenly throughout its structure, and transfers them into the mountains/hills at the sides of the dam. A crack shifts the stresses which would've been borne by the cracked section to the uncracked sections, and particularly at the corners of the cracks. The high stresses at the corners cause the crack to grow. Eventually the crack grows large enough that the stresses are more than the uncracked section can withstand, and the dam fails.
That's what the engineer noticed. The dam was bulging because the uncracked section was holding back so much more stress than its design load that it physically deformed. 65 feet is a damn big crack (no pun intended). That engineer deserves a ticker tape parade in his honor.