City water system is less vulnerable

When water flows from the faucet it's hard to see the planning and technology behind a utility that is taken for granted.

Until October 2002, Sisters' city water was extremely vulnerable. Sisters had one 12-inch pipe supplying the town, twice crossing under the sometimes torrid waters of Squaw Creek.

A mile south of town there is an elbow in the water line coming down from Pole Creek Reservoir. The old water line banks to the right in a northeast direction. At this elbow, city workers patched in the new line which heads straight for Pine Meadow Ranch.

At this valve the old line can be turned off. Near this site a partially exposed section of the old pipe can be seen in Squaw Creek.

According to Gary Frazee, Public Works Director, in the mid-1970s the Oregon Department of Fish and Wildlife required the city to drop boulders in along the bank at this particular section of the creek. Most of those boulders have now washed downstream and since then the pipe has became exposed in the bottom of the creek bed.

The movement of these boulders indicates the strength of Squaw Creek's water flow.

Further south the water line originates at the Pole Creek Reservoir. There are two reservoirs at this site. The old one looks like a pond. The newer reservoir is a large concrete structure with 28-foot walls and is 55 feet in diameter. Water is pumped up to this reservoir and then gravity fed back down to town. Fourteen feet of the wall can be seen; the other 14 feet is below ground level.

The reservoir holds 1.6 million gallons of water. The old reservoir holds 2.3 million gallons.

The old reservoir was abandoned in 1997. It used a sand filtration system to purify the water. In 1994 the Health Division required the city to add 18 more inches of sand to the existing three feet to meet safe drinking water standards.

"After we did this we couldn't get any water out of the darn thing," Frazee said.

That was only one of the reservoir's problems.

The water right from Pole Creek only allowed the city to draw 130,000 gallons a day.

The old reservoir is lined with clay to prevent water loss from seepage.

Frustrated city water officials drained and lined the reservoir with clay three times in order to stop the leak. Former city water masters then brought it to their attention that they believed there were underground springs bubbling up into the bottom of the reservoir, creating the leakage.

"The old reservoir became cost prohibitive after the extra sand, the minimal water rights, the booster pump, and continuous attempts to fix the leak," said Frazee.

"Now we have a good system," the public works director said.

The new reservoir is on two wells: one at Sisters Middle School and one along Three Creeks Road. Frazee said that when the new reservoir gets below 10 feet from the top, a sensor triggers one of the wells to activate automatically.

The well at the middle school pumps 800 gallons per minute. Sisters uses on average 200 to 300 gallons per minute. The extra 500 gallons from the well's supply reverses the flow of the water and fills the tank at Pole Creek. So, the well fills the reservoir while supplying the city with water.

The new water line feeds at an average rate of 300 gallons a minute. Near maximum flow it reaches 1,800 gallons per minute, helping to ensure a steady supply of water to the City of Sisters.