SPOKANE, Wash. -

In normal years, we would have received almost two feet of snow by now in Spokane but so far we've only had to shovel about six and a half inches. While skiers might be grousing about it in the mountains, construction crews are not down in the city.

Here in the dead of winter a lot of concrete is getting poured and no one is missing the mud. In fact, a construction crew on a waste water storage vault project on the South Hill is ahead of schedule because they're not having to shovel snow just to get to work.

"On the south side we have what are called combined sewers. They're sanitary sewers. So we get that big rain and it all dumps into the sewer at times it becomes overwhelmed," Marlene Feist with the City of Spokane said.

To prevent sewer pipes from rupturing during downpours a combination of runoff and untreated sewage is dumped into the Spokane River. It doesn't happen very often but it's pretty gross for the people downstream.

"It trips a regulator so it flows out into the river so that the pipe doesn't burst. So it's sort of a safety valve but at the same time we don't want that flow to going into the river," Feist said.

That's why the city is building a million gallon vault along Ray Street on the South Hill to briefly store sewage and runoff until it can be treated. And, thanks to the dry winter, the work is ahead of schedule.

"It's been a relatively mild winter and we're really benefiting from it. We're ahead of schedule right now because of the weather we've been having this winter," Paul Clary with Clearwater Construction said.

The company's president has a vested interest in the project because he lives downstream of the storm water that falls out on Lake Spokane.

"This water that would otherwise discharge directly into the Spokane River is now going to be caught by this tank and filtered back to the wastewater treatment plant to be treated instead of dumping raw sewage," Clary said.

The city is preparing to build another storm water runoff tank just below Underhill Park.