The Apparent Predicament of Grand Coulee Dam            

(A Potential "Sitting Duck" in a Major Earthquake ?   And, Why is there So Much Gold Here and Where did All That Gold Go ?)


During the excavation for the foundation of Grand Coulee Dam, which dam is located on the Columbia River in Washington State, two main sets of vertical or near vertical fissures were found in the bedrock. These fissures went deep into the granite bedrock beneath the dam site. How deep into the bedrock these fissues went, no one at the time really knew. And what these fissures were actually associated with, once again, no one knew at the time. But, they just went ahead and built this huge dam at this location anyway.

There is more to consider about the fissures in the bedrock beneath Grand Coulee Dam. One main set of fissures is east-west trending and the other is north-south trending. There was also a "lift-seam" found in the bedrock beneath the dam and another found beneath the associated pumping station. It was known that these "lift-seams" could potentially destabilize these facilities in the event of a major earthquake. After much cleaning, the "lift-seams" were filled with as much grout at possible. It was "unprecedented" grouting.

Not only are there fissures and a "lift-seam" in the bedrock beneath the dam, but there are also a number of fault lines. And then, under the east end of the dam, there was that great gulch which needed to be excavated. It was excavated about 120 feet deeper into the bedrock than excavations elsewhere on the dam site. This was done in an attempt to "clean up" the fractured bedrock and "stabilize" and "seal" a serious fault. This was a deep, north-trending fault which ran parallel with the river. But there is more to this story.

There are actually two major, north-trending fault lines which bracket the Grand Coulee Dam site. One of these major, north-trending faults is located to the east of the dam site and the other is located to the west of the site. These major fault lines are rather long. They extend northward all the way into Canada. Looking the other direction, how far south of the Grand Coulee site do these fault lines extend? No one knows for sure. Why? To the south of the dam, these major fault lines are buried under the Columbia River Flood Basalts.

In 1872, prior to the construction of Grand Coulee Dam, this region experienced a major earthquake. It was the largest recorded quake in Washington. At that time, there were few people living in this inland region. As a result, no one is completely sure where the epicenter for this major quake was located. But the quake was felt throughout much of the Pacific Northwest and into Canada. And today, the Pacific Northwest is facing the potential for a great Cascadia earthquake, which could affect the inland region more than expected.

The full report considers those two main sets of vertical or near vertical fissures to a large degree, which were found in the bedrock beneath the Grand Coulee dam site, as they excavated downward and prepared to lay the foundation. The report provides information about the major seismic features which the deep fissures in the bedrock are actually associated with. And then, as a further indicator of past seismic activity in the area where the dam is located, the report looks at all the gold in this region.

While they were excavating the bedrock, in preparation for the dam foundation, they also found that there were "extensive shear zones" in the bedrock. At the time, they did not know what these "extensive shear zones" were associated with, so they just went ahead and built a large dam at this site. It appears that the many "signs" were being ignored. Now it is known what those "extensive shear zones" are associated with and what they tend to indicate. Yes, a lot of serious seismic activity has occurred here in the past.

During the extensive, deep excavation for the foundation of Grand Coulee Dam, it appears that they punctured into an underground river. It appears that this is something which they wanted the workers to keep quiet about. Research indicates that this "underground river" was actually the Odessa Aquifer. So, what was done about this apparent breach into the Odessa Aquifer? Well, there was a lot of grout on hand, so that appears to be what was used to quickly cover the flooding breach.

At this point, the water table is declining rapidly in the Odessa Aquifer. The writer raises the issue that part of the reason for this declining aquifer may be that puncture into the aquifer beneath Grand Coulee Dam. Possibly an inproper sealing job is allowing for leakage from the aquifer. And over time, with associated erosion, this leakage will only continue to increase. This could be at least part of the reason why the water table in the aquifer is declining at a faster rate than was possibly expected.

The full report considers some of the major seismic hazards in the Grand Coulee region. It considers the potential for Grand Coulee Dam to be seriously damaged or to fail, in the event of a major earthquake in this region. If this dam were to fail, the debris-laden flash flood blasting downriver could cause a large loss of life and property. The loss of electrical production and irrigation water for agricultural purposes, which this facility now provides, could create additional hardship in this region. But, there is more to consider here.

The debris-laden flash flood from a failure of Grand Coulee Dam could effect downriver dams, potentially causing some of them to fail. This debris-laden flash flood could also cause serious erosion at the Hanford Nuclear Reservation, which is located along the Columbia River, downstream from the Grand Coulee facility. Serious erosion at the Hanford facility could scour out and spread harmful or deadly radionuclides throughout a large area. This spread of radionuclides would affect cities all the way to the Pacific Ocean.

At this point, there are some very important questions to ask. Has the general public been properly made aware of the potential risk which exists in this inland region of the Pacific Northwest, or has there been a denial of the true risk and more of an ongoing cover-up? Have disaster preparedness plans been set in place in this region which could properly address a major earthquake event, an event which could include the failure of Grand Coulee Dam and its pumping plant, plus the serious spread of radionuclides?

There is more to consider about the potential for this major disaster in the Pacific Northwest. There is the Cascadia megaquake which has been spoken about for years, and again, there was the Washington earthquake of 1872, which appears to have been mainly centered east of the Cascade Mountains. Could one of these events in our time set off a repeat of the other? Is there a chance that there could be a widespread seismic event which could affect the whole Pacific Northwest, even far inland from the coast?

All of the above issues are raised in the full report. These are issues which need to be addressed now, not later, after the fact. The report fills in many more details about the predicament of Grand Coulee Dam --- a dam which is built where two major fault zones cross. It also provides information about the area where Grand Coulee Dam is located being greatly shaken during the Washington earthquake of 1872. And, that major quake occurred not that long before someone decided to build a major dam here, on top of faults.

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