At last week’s city council workshop, council members learned about an unsuccessful attempt to gauge the entry point of fluoride into Well No. 6, the city’s most productive well.
The council earlier decided to go ahead with studies of Well No. 6 to determine where fluoride is entering the well from the aquifer and how much water is coming in from each aquifer layer.
Alan Schroeder, Anderson Perry engineer, reiterated the two issues they are dealing with at Well No. 6: the high fluoride levels and the state Department of Ecology’s prohibition against the co-mingling of waters from different aquifers. He said that at some point he expects Ecology officials to come back and see what the city is doing to prevent that.
The well taps into the Grand Rhonde and the Wanapum, defined decades ago as two aquifers by the state Department of Ecology. In reality, there’s more than just the two levels of water.
An e-mail from geologist Kevin Lindsey to Schroeder explained that the upper portion of the well produces about 700 gallons per minute while the water production below the pump produces about 1,600 gallons per minute. Lindsey wrote that technical difficulties prevented them from getting water quality samples, so they still don’t know which water zone below the pump is bringing in fluoride. He also noted he doesn’t think fluoride is coming in at the 800-foot depth, but suspects it is coming in at a depth below 900 feet, where at least half of the well’s production comes from.
Lindsey listed a few possibilities about how to proceed: one to pull the pump column and seal off the lower zones one at a time and test the water as each zone is sealed off. He called this an expensive proposition but one that would yield good water quality and production information. Another possibility is to pull the pump column and just seal off the lower two or three zones, which he said would result in a good, rebuilt well with the least amount of messing around.
Schroeder told the council additional water sampling analysis would cost about $70,000. Mayor Shannon McKay noted that while Well No. 6 is the city’s most productive well, the state Department of Ecology restricts use of the well to emergencies, and suggested that if less water is pumped from the well, the unused water rights could be used at another site.
Public works director Jay Van Ness told the council that the timing of taking Well No. 6 offline for work will be critical and should be done at a time of year when water demands are not high.
The city’s well situation is vulnerable. On Aug. 29, Well No. 3 and Well No. 5 both broke down, and last May both Well No. 4 and Well No. 5 were down at the same time.
The session was informational and council members did not take any action about how to proceed with Well No. 6.