Wichita street sweepers are out, running night and day.  They're trying to get as much sand off the roads as possible before predicted rains fall later this week.  What goes down before a storm, must be picked up after. 

"We're trying to sweep up all the sand that we put down in combating the most recent snow storm," said Aaron Henning, with the Wichita Public Works Department.

State and federal law say they have to, even if the sweepers slow down traffic at times.

But why?  All that sand goes down the storm drains and into rivers.

That traffic on the roads adds things like oil and heavy metals and a lot of other contaminants to the sand which means, even though the sand is from Kansas, they don't want it to get into our lakes and rivers.  That can kill fish or poison them with heavy metals like mercury.

In addition, the sand can make dry roads slick, especially at intersections, and can clog up city drains causing street flooding problems.  Not to mention, it just looks bad.

"We want to prevent that as much as we can," said Henning.  Which is why "we sweep year round."

But there's an extra note of urgency this week.

"Well, we do hope to get as much as we can before the rain hits," Henning said.  "Which will obviously take more of it to the river than otherwise would go."

It will take city crews four to six weeks to complete the job.  They have 1,200 miles of lanes to clean across the city.  To put that in perspective, that would be like driving from Wichita to Las Vegas, on something about as fast as a lawnmower.

Getting the streets ready for rain.