Among the whirs of pumps and filters at Kelso’s water plant, water is flowing with great efficiency from below the Cowlitz River to nearly 12,000 homes and businesses.
The best part?
“We get very few water quality complaints,” Kelso Public Works Superintendent Randy Johnson said.
The riverbed Ranney wells have served the city full-time since 1984. (They were installed in 1979 but mud flows from the 1980 eruption of Mount St. Helens put that on hold.)
It hasn’t been a seamless 30 years, but with a few upgrades here and there, the wells have served the city well.
So why, when Longview started looking for a new water supply a decade ago, was a similar system glossed over?
Blame the consultants.
“I don’t know details of how far up and down the river they looked, but (the city was told) it would not have been economically feasible,” Longview Public Works Director Jeff Cameron said. “(Consultants) Kennedy/Jenks or Layne Engineering did not even do a cost estimate at this point.”
Ranney wells collect naturally pre-filtered water from riverbeds through horizontal pipes 15 to 25 feet below the surface. Finding the right location for them means finding a drillable area with high water quality and enough long-term capacity.
Which, at a glance, wasn’t found. So it was decided that the Mint Farm wells were the best option in replacing the Cowlitz River plant at Fisher’s Lane.
That hasn’t gone over so well, with water quality complaints flooding City Hall over taste, odor, hardness and silica spotting and staining.
In fact, a citizen committee is recommending that Longview install a Ranney system on the Cowlitz just a year and a half after the $33 million Mint Farm plant came online. Should the City Council go along with it, it will cause a big rate increase on top of the rate increases caused by the Mint Farm move.
In total, it could cost more than refurbishing the Fishers Lane plant would have cost to begin with.
Where the city’s earlier consultants looked for a Ranney system was important. Officials said with Kelso’s system it came down to the old real estate adage: location, location, location.
“With the location we had it was the most economical choice,” said Kelso Water Treatment Plant Supervisor Paul Reebs.
With this round of water supply studying in Longview, consultants may have found that sweet spot.
“It may be that Layne Engineering is taking a fresh look, looking farther up the river,” Cameron said.
He also noted that Longview’s demand for water has fallen, giving the limited capacity of Ranney wells a better chance in the long-term that may not have existed when the city was first looking to change water supplies.
Ranney wells, also used by Kalama, Woodland and St. Helens, take “groundwater under the influence of surface water,” meaning there are some surface water rules to adhere to, but far fewer risks than actually drawing from the surface of a river.
“From the surface there are a wide variety of temperatures, turbidity and contaminants,” Reebs said. “Wells or Ranney wells are much more consistent and easier to deal with.”
Longview had looked at joining Kelso’s system to replace the old Fisher’s Lane plant, but the capacity there just wouldn’t be enough. At the time, Cameron said Kelso was also having trouble with iron bacteria.
That is one ongoing maintenance problem with Ranney wells. The pipes need cleaning on a three-year basis, and to do so requires sending a diver into the vertical caisson that connects to the outlying collector pipes.
Still, that beats silica spotting, according to Longview’s water committee.