Construction of a huge new stormwater collection tank will cause the closure of Sprague Avenue at Jefferson Street starting on Monday.
For the next five-plus weeks, workers will be redoing existing utility lines to get ready for the excavation of city-owned property at Sprague and Adams Street just west of KHQ-TV.
Westbound traffic on Sprague will be detoured at Madison or Jefferson Street to Riverside Avenue to the north.
The intersection of Cedar, Riverside Avenue and Sprague will be kept open as much as possible, city officials said.
Spokane transit buses will be using Riverside Avenue at Jefferson for the agency’s routes there.
Halme Construction, of Spokane, is the contractor on the $16 million job that’s being financed with utility revenue, said Julie Happy, city spokeswoman.
The plan calls for building a 2.3 million gallon tank in the half block that was once home to a city fire station. In comparison, the stormwater tank being installed next to Veterans Court is 1 million gallons.
It is not clear whether Sprague will be reopened during phase two of construction, which will likely last until the fall of 2018, Happy said. The traffic plan for that phase is still being developed.
The tank will collect stormwater from the southwest section of the South Hill and the west end of the downtown area, Happy said.
For years, heavy runoff from rainstorms or snow melt has caused a combination of sewage and stormwater to be released directly into the Spokane River, which has been done to protect the wastewater treatment plant next to Riverside State Park from being inundated by storms.
The tank will store stormwater during heavy runoff and then send it slowly to the treatment plant to be processed into cleaned discharge water.
Numerous such tanks are going into the ground around the city, including a $20 million tank holding 2.2 million gallons just west of City Hall, which will begin construction this year.
The projects are part of a multiyear effort to reduce pollution of the Spokane River under the federal Clean Water Act.
The projects will ultimately total more than $300 million in spending.
The lot at Sprague and Adams where the tank will be buried was the location of Fire Station No. 4, which was relocated to the Maple Street bridge loop to the west.
The city sold the property and then bought it back from Ron Wells last year for $868,000, more than the $500,000 the city sold it for in 2004. Wells had demolished the old station building in 2006.