As dry conditions pervaded May and continue into June, the City of Wrangell has issued a public notice requesting that residents conserve water after its two reservoirs dipped below the usual levels. Residents and businesses are asked to begin reducing their water consumption until normal levels are restored.
Wrangell received only 0.6 inches of precipitation for the month of May, down from a historical average of of 4.58 inches. Other communities in Southeast have also noted record dry months, with Juneau registering 0.52 inches of rainfall for the month and the ordinarily-inclement city of Ketchikan receiving less than 0.7 inches.
Over the past month its 45-million gallon upper reservoir has dipped by about a foot, and the 21-million gallon lower reservoir has dipped by around four feet. A lack of snowpack on the island that would ordinarily make its watery way into the reservoirs has contributed to the difficulty by making the system more dependent on rainfall it has not lately been receiving. Complicating matters, lower head pressure caused by dwindling reservoir levels reduce system capacity because it is gravity-fed.
"It's not just what we see. There's other effects as well," explained Amber Al-Haddad, head of Wrangell's Public Works Department. A substantial amount of rain will be needed to replenish the reservoirs to brimming point, which will be important once the seafood processors ramp up production later in the summer. In a season, Al-Haddad estimated the canneries can by themselves go through a third of the community's reserved water.
"We're not in a drought situation yet, and hopefully we won't get there," she said. By being mindful of consumption now she feels more confident the community can better weather this dry spell as the summer goes on.
The city is also looking at ways to make its water treatment provision more efficient, with Public Works pursuing a drinking water pilot study this summer. Six proposals were received in late April, from which the department will select a firm to undertake the project.
A grant was received last year from the Department of Commerce, Community and Economic Development to undertake the study, which will test the water treatment process with an aim to eventually improve Wrangell's current filtration system.
Built in 1999, the water treatment plant was designed to produce 1.3 million gallons of water per day, but the sand filtration system has proven a limiting factor.
"It's a little bit inefficient," explained Ruby McMurren, Public Works project director. Wrangell's filtration system was fashioned after one used in Sitka, though differences in the water quality have made it less suitable. The water coming from Wrangell's two reservoirs have sediment issues, as the reservoirs are creek-fed and use an earthen dam.
Water and wastewater operator Jeffery Davidson explained that in periods of low rainfall the sediment issue tends to worsen, as runoff overflowing at the reservoirs has a cleansing effect by skimming the surface.
"If we get a good rain it makes our job easier," he said.
Higher levels of turbidity in the water means it takes longer to filter, adding also to maintenance and operating costs. The city's two tanks for treated water can together hold 848,000 gallons, but the facility can still struggle to meet increased demands during the summer when fish processing and cruise ship water needs are at their peak.
From the drinking water study, Public Works expects to see a recommendation of a new and improved treatment process to meet or exceed state drinking water regulations while also keeping up with high usage demands.
"We want really the best we can get here," McMurren said. More information will be available once a firm is chosen to undertake the pilot study.
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