News and Opinion from Sisters, Oregon
News and Opinion from Sisters, Oregon
Sisters is running out of space to spray treated effluent. photo by Jim Cornelius
It's only been in operation for two years, but Sisters' municipal sewer system is already bumping up against its capacity limits.
The City of Sisters is rapidly running out of space where effluent can be sprayed. The treated effluent is currently sprayed on 87 acres of forest land south of town.
According to City Administrator Eileen Stein, city staff was worried that the irrigation limit might be hit this summer. The installation of some new sprinklers on the sewer pond dikes pushed off that looming crisis, but only for a while.
"I think we're going to be able to hold the effluent dispersal for another year or two," Stein said.
The sewer treatment site covers 160 acres south of town. Of that, 87 acres is under irrigation. Treatment ponds cover 40 acres and there is a 300-foot setback between the sewer site and Buck Run to act as a buffer zone.
That 300-foot zone was originally to be irrigated, but the city council subsequently decided to leave that area unused.
The treatment plant itself could reach capacity by 2007, according to Stein and Public Works Director Gary Frazee. The plant was designed to carry the system to 2017.
The estimate of when the system will hit capacity is based on new population projections from Deschutes County. Those projections may or may not prove accurate, but nobody questions the obvious, rapid growth seen in Sisters in the wake of the sewer system's installation.
"There's still a debate about whether the rate of growth right now is pent up demand," Stein noted.
If that is the case, the initial burst of growth may taper off, delaying the need to expand facilities. But the growth curve may continue to rise and the city must plan for running out of sewer capacity much sooner than expected.
The city assesses Systems Development Charges (SDCs) for new construction and users coming onto the sewer system. Those SDCs should enable the city to pay for expansion of the system without hitting ratepayers with higher monthly bills.
"We're supposed to have the money in the bank when it comes time to expand," Frazee said.
The city has insisted on full payment of SDCs and assessment of new construction (such as the new Sisters High School) at design capacity instead of occupancy. That, city officials agree, has helped ensure that the funds are in hand for sewer plant expansion.
The city currently has $1.4 million in its sewer SDC account, according to Stein.
The cost of expansion is not known at this time. The city will have to acquire more land from the U.S. Forest Service for effluent disposal. Then the city will have to build a new holding and treatment pond.
There are some options for increasing the amount of effluent that can be dispersed on the land already under irrigation.
According to Frazee, the city is allowed to put out 17 inches of treated water spraying on the forest floor. If the city was irrigating a crop, it would be allowed about 27 inches, he said.
Frazee said his staff is researching options for cash crops, including an aspen tree farm. A hay crop is an obvious possibility.
"The problem with a hay crop is that we'd have to clear the trees, so I don't know if that's an option," Frazee said.
Frazee noted that reclaimed water has become increasingly valuable to farmers and ranchers as water allocation issues become more complex.
The city will explore providing effluent to landowners as part of its research on plant expansion.
The looming capacity limits may be surprising for a system that is only a couple of years old, but it is unlikely that a bigger plant could have been built.
Frazee noted that the grants that funded most of the project would not allow the city to "overbuild" the system in anticipation of growth.
Yet the very existence of a municipal sewer system allowed growth in Sisters -- including higher residential densities and water-intensive commercial uses like a Laundromat -- that was not possible when the whole city was on septic systems.
The city council and then-Mayor Steve Wilson also committed early on to a $39 per month per residence (or "equivalent dwelling unit") sewer rate.
With grants restricted to "current need" and without a high-priced rate structure, the current plant was as large as the city could afford to build at the time.
With the sewer came growth -- and SDCs.
With those SDCs in place, the city may have to build more capacity sooner than planned, but it will have the funds to pay for the work.
Jim Cornelius is editor in chief of The Nugget and author of “Warriors of the Wildlands: True Tales of the Frontier Partisans.” A history buff, he explores frontier history across three centuries and several continents on his podcast, The Frontier Partisans. For more information visit www.frontierpartisans.com.
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