Last week, a colleague and I went on a field trip hosted by the Portland Water Bureau to the Bull Run Watershed, which is the primary water supply for the City of Portland and its multiple wholesale customers (including the City of Beaverton). The 102 square-mile watershed is located in the Mt. Hood National Forest about 26 miles from Portland. As one would expect, the watershed is not open to the public and the Bureau imposes strict restrictions on anyone entering. No touching of the water is allowed!
If for any reason there is not enough water from the Bull Run watershed or there is a problem with the water, the Bureau supplements or substitutes the water supply using groundwater from a wellfield located near the Portland airport.
Our first stop on this tour was a small hike to the spring that is the genesis of the Bull Run River. This water originates from Bull Run Lake located on the east side of the watershed. Contrary to often-held opinion, the water does not come from Mount Hood. Multiple springs continue to feed the river along its path (which is basically the lake water moving downhill through the ground), as well as snowmelt and rainwater. The river then drains into two reservoirs created by Dam 1 and Dam 2.
We enjoyed a lunch by the lake, sitting on the porch of one of the old cabins used to house the workers building the dam.
Next we stopped at Dam 1, an arch-gravity dam, which is an impressive structure considering its remote location and the fact that it was constructed between 1925 and 1929 (and was also the prototype for Hoover Dam). Supplies were brought by horse. The designers of the dam built in pipes for hydroelectric power and Dam 1 has been generating electricity since about 1982. The cool, damp tunnel that traverses the bottom of the dam (about 160 feet across of solid concrete) provided us a welcome respite from the brutal sun that day.
Dam 2 is an earthen structure and was not much to look at. We next drove by the so-called "headworks" which is where the raw water enters the water supply pipes and where it is chlorinated. A bit farther down-pipe, ammonia is also added to the water in a process called chloramination, which is necessary to ensure the chlorine does not evaporate before it gets to the consumers' taps. The water is not filtered and it is delivered using mostly gravity and not any form of powered pumps.
I highly recommend this trip—not only does it take visitors through a beautiful forest, but it also shows a snapshot of Oregon history that's still relevant today each time we turn on the water tap. Besides, I guarantee that you will never think of your drinking water the same way again. Portlanders are fortunate to have this readily available clean and natural water that is filtered by old growth forests—almost 95 percent of the watershed is forested, primarily by Douglas fir, western hemlock and Pacific silver fir –and understory plants such as salal and ferns. It now seems (even more) ridiculous to drink store-bought water in plastic bottles when this clean water comes straight out of our taps (unless you live in a house with old pipes). So, drink up, Portland!