Unlikely as it may seem, the massive berms of snow left around Spokane in the wake of storms and a prolonged arctic chill are going to melt.
Overnight lows are forecast to remain above freezing, with rain anticipated all week. That means the roughly 10 inches of snow that has piled up over the past few weeks around town will be melting fast, testing stormwater pipes and the massive underground tanks the city has been installing to store combined sewage and stormwater before it’s treated and discharged into the Spokane River.
“We will have overflows,” said Marlene Feist, a spokeswoman for the city’s Public Works Division. “There’s no way to avoid that.”
In 2013, the city approved a plan to build 11 new underground tanks that will bring underground capacity up to 14.3 million gallons before runoff tips the limit and combined sewer and stormwater overflow runs untreated into the river.
Some of those tanks are already online — three massive reservoirs, including the 1-million-gallon tank being buried under the Bosch parking lot on the north side of the Monroe Street Bridge. Two other tanks, one near downtown and the other at the intersection of First Avenue and Adams Street, will begin construction this year.
The tanks are designed to bring the city in line with a mandate from the Department of Ecology to limit untreated water flowing into the river at 20 sites to once per year. In the 1970s, that number was closer to 1,000 per year, spilling more than 700 million gallons of untreated water into the river.
Over the past five years, the average amount of untreated water that has entered the river as a result of system overflows has been about 52 million gallons, according to numbers reported to the Ecology Department by the city.
Brook Beeler, a spokeswoman with the Ecology Department, said the agency was more concerned about overflows in the summer months, when warmer temperatures are more conducive to algae blooms and water levels in the Spokane River are lower.
To make sure the melting snow finds its way easily into the system and not in ponds on city streets, both the Ecology Department and city are urging residents to clear drains around their homes of ice.
