Sega

Field Experience to Grand Coulee Dam

When doing preliminary research about the Grand Coulee Dam, it became evident that it is perhaps the most important construct in the state of Washington. The dam is not just used to control floods, or provide irrigation to over 500,000 acres of farmland, but it is also the number one source of electricity in Washington. The dam also made it possible to turn the fertile, but waterless desert land in Eastern Washington into a vast agricultural economic system. By being the most powerful generator of hydro-electricity in North America, and supplying much needed water to farmlands in Washington, the Grand Coulee Dam is one of the most economically beneficial constructs in the state.

To prepare for the visit to the dam, research was done to find out where the different operations were performed. Finding the layout of the area turned into the day's agenda. First, the visit would start on the east side of the river where the third power house is located. From there the journey would head east across the river to see the other power facilities, as then lastly visit the irrigation facilities. The primary data collected will be direct observation of the facilities to determine how it produces electricity, how the irrigation system works, and what negative impact the dam has on the local ecosystems.

The Third powerhouse was quite a site. Obviously, it's a massive concrete structure with Lake Roosevelt on one side, and the outgoing Columbia River on the other. It was interesting to see how they leveraged the natural shape of Lake Roosevelt to get the most waterpower to this station. Instead of building the dam straight across the river, they went straight across the river about 85% of the way, and then angled the rest of the dam northward to meet a protruding rock bed. This enabled them to get a large powerhouse with six great generators that can produce up to 800 Megawatts of electricity. This process occurs through six separate generators. This concrete structure looks as though it naturally emerged from the rock hill that towers over the east side of the river.

Heading westward across the dam from the Third powerhouse, the next facility is the Right powerhouse. Of all the dedicated powerhouses, this one produces the least amount of total megawatts. It is located along the straight part of the dam, just west of the Third powerhouse. From the exterior one could not even tell if there was anything happening inside the concrete walls. However, when standing over this part of the dam it is evident that something more is going on than the eyes can tell, mainly because of the loud sounds generated by the vast amount of water flowing beneath the walkway. This is the sound of nine 18-foot tubes full of water barreling through 300 ft. of concrete walls below the surface of dam.

Approaching the edge of the west bank of the Columbia River over the dam construct, the Left powerhouse is crossed. This powerhouse contains a main generator the same size as the Right powerhouse, but it also includes a service station that is capable of producing an extra 30 megawatts of electricity. The most interesting thing observed when standing over this part of the dam is that the beginning of the irrigation system is visible. The opening of the irrigation system where the water from Lake Roosevelt is taken up by 12 pumps is seen by peering southwest. Moving up the hillside 12 pipes, which originate at the irrigation system opening, are seen rising through the ground as if coming from nowhere.

The Columbia Basin Irrigation Project is responsible for turning a portion of Eastern Washington into an agricultural wonderland. Over half a million acres of farmland are fed water from what is called a feeder canal that is filled with water from the Columbia River via Lake Roosevelt. The feeder canal is supplied by six older 65K horsepower pumps, & six newer 67.5K horsepower pumps that double as generators. This irrigation system is actually a little upstream from the dam. The separation of the two facilities means nothing, as the dam and irrigation system work hand in hand.

The six older irrigation pumps are connected directly to three generators in the left powerhouse. It takes one whole generator to power two of the older pumps. However, the generators are only dedicated to the older pumps during the growing season, when the pump is providing water to the crops at a rate of 1,600 cubic feet per second. (3) During the winter the pumps are repurposed to provide electricity to heat homes and offices when they need it most. This physical connection between the irrigation and dam facilities cannot be seen on the exterior; it is buried underground.

The six newer irrigation pumps are a little more dynamic than the older ones. Instead of requiring dedicated generators from a powerhouse, they feed off of the power grid above the dam. What's even better is