The city should be better prepared to meet its water needs this summer, the Borough Assembly learned last week.
City manager Jeff Jabusch brought members up to speed on where Wrangell Public Works stands with its water plant situation.
Last July the community was put into a state of high anxiety when its supply of potable water was reduced to less than half a tank, while the water treatment plant was unable to keep up with demand. A longstanding problem with the system has been its filtration method, relying on slow sand filtration. Maintenance needs exacerbated by high turbidity in the water supply had reduced outflow, and shortcomings in the system’s design caused further inefficiencies.
To head off the chance of a repeat season, Jabusch explained plant workers would attempt to thoroughly clean out the sand in the filtration system, something which has not been done since it was first installed. Initially the expectation had been that the filtration bays would only need to be agitated periodically, once or twice a year. But the system was ill-equipped to handle the sedimentation in Wrangell’s water supply, and over the years each of the four bays has needed attention on a more regular basis.
Jabusch reported the city is in touch with a contractor capable of removing and running the sand through a cleaning system. “We’ve got prices to get some small, temporary equipment to do that,” he said.
The project can start as soon as the weather warms up, and can be completed well before demand picks up in the summer. Additionally, Jabusch said he will be speaking with both of Wrangell’s commercial seafood processors this month about efficiencies they have enacted since last summer. A wider outreach to the community may also be undertaken beginning in June, advising residents on ways to reduce personal consumption.
“We’re as prepared as we can possibly be when we come to the summer,” he said.
Assembly members also recommended putting together a response plan, setting out appropriate courses of action once certain conditions were met. This could include ceasing sale of water to cruise ships when water reserves reached a certain level, and the institution of emergency restrictions on washing vehicles and sprinklers.
“I think one thing that was a good idea, was also having a plan,” said Jabusch. He will be retiring at the month’s end, and he felt it would be useful to have a response prepared for his eventual successor.
For the longer term, the city is continuing to develop alternate means of treating its water supply. In 2015 an engineering firm was contracted to conduct a pilot study. A test plant thought to be better suited to raw water quality conditions was installed last summer, using dissolved air flotation. This uses air bubbles to draw sediment to the water’s surface, which is then automatically skimmed away.
The plant worked well, but cost estimates released in January for a full-sized plant came in at more than double what was first estimated. Rather than $6 million, the facility could run at around $13 million, which would be prohibitive to the project.
Jabusch reported that cost has since been reduced to $8.5 million. The biggest portion of the unexpected increase – by about $2.5 million – had been the construction of a new building to house the facility. Included in the costs were the additional inspections, contingencies, and design costs involved in construction.
“That pretty much jumped up the building and all that goes with that,” said Jabusch. Getting back to the design contractor, city staff recommended using existing structures to house the new plant. “We’re still working with the engineers.”
Lowering the overall project cost improves Wrangell’s chances of securing grant funding, Jabusch expected, though that would not be a guarantee. The city would be reaching out to its lobbyists and congressional delegation for support as well.
“We’re kind of doing both these things at the same time,” he said. “We are doing everything we can, both for the upcoming water season and the new plant.”
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