GRANDVIEW - All of the wastewater in Grandview at one time or another travels from the South Euclid Road pump station, under the Yakima River to the Grandview wastewater treatment plant. Wednesday, Aug. 11, crews at the local treatment plant noticed wastewater rising in the river during a routine check of the plant's back-up systems.
Last week, it was confirmed that the wastewater leakage was coming from a 10-foot long, 1/2-inch wide crack in one of the two 20-inch water mains that are used to transport wastewater from the Euclid pump station to the treatment plant.
Last night, the Grandview City Council called an emergency meeting to discuss the problem and find a solution.
Grandview Public Works Director Cus Arteaga explained that the damaged east main is currently used as part of the wastewater treatment plant's back-up system. He noted that both 20-inch mains that cross the Yakima River were first installed in 1981, with the east pipe being used to regularly transport wastewater across the river, until four years ago when improvements were made to the Euclid pump station.
Arteaga explained that the upgrades included the construction of a 100,000-gallon storage basin and the installation of an engine-driven back-up pump, that in case of emergency would pump wastewater from the basin, across the river to the treatment plant. He noted that the upgrades also meant dedicating the east pipe, which already had 20 years of use, to the back-up system.
Arteaga said that the back-up system is only set to be used when electricity is lost and the back-up generator doesn't kick in to operate the three electric pumps that pump wastewater across the river on a day-to-day basis.
Ted Pooler with Huibregtse Louman and Associates told city council members Monday night that the crack was discovered after 5,000 gallons of wastewater leaked into the Yakima River during a routine check of the back-up system. Arteaga said the back-up system is checked quarterly.
Pooler said as soon as the wastewater was seen coming up in the river, the pumps were shut down. He added that on Aug. 17, it was confirmed that there was a leak in the east main, when dyed water was run through the pipe and showed up in the river.
Pooler told council that on Aug. 19, a camera was inserted into the main and sent down the length of the pipe. He said the crack was found about 90 feet from the river bank.
Pooler then showed a video of the camera's journey through the pipe to council, pointing out where the crack is located. He noted that at points along the crack it is possible to see the river bottom.
Following Pooler's presentation, he introduced four repair options to council. The first option was to replace only the damaged section of the pipe, another option was to insert a pipe liner in only the damaged section of the pipe, and the third option was to replace either one or both of the 20-inch mains that run across the river. The fourth option introduced to council called for the insertion of a pipe liner into the entire length of the either just the east main, or both the east and west pipes.
Pooler noted one advantage of using a liner is that it wouldn't make it necessary to actually get into the river to do the repairs, which would mean dealing with the Environmental Protection Agency.
Mayor Mike Bren asked if it would be necessary to line both pipes at the same time. He noted that since the west pipe has only had about four years of regular use, he would like to see a camera go through that pipe to see if a liner is really needed before council opts to set aside funds to have the second pipe lined at the same time.
"Sometimes it's different when you're not behind the eight ball," Bren said.
Pooler estimated the cost of lining the east pipe, which has the crack in it, to be $116,369. The estimate to line the west pipe is $111,936.
City Administrator Jim Sewell explained that the money to make the emergency repair would come from the city's water and sewer fund, which he noted currently has a $1.4 million fund balance. Sewell explained that the impact this will have on sewer rates has yet to be determined.
After listening to the presentation, council voted to line the east pipe, with the option of lining the west pipe if it is determined to be necessary.
. Elena Olmstead can be contacted at (509) 837-4500, or e-mail her at email@example.com