Superior Stormwater is a project by the Environmental Services Division of the Public Works Department for the City of Superior, Wisconsin. The blog is a way to bring information about stormwater and related topics to the public. Please let us know if there are any topics you'd like us to cover! For more information, check out our website at www.ci.superior.wi.us!
outfall is defined as any “point at which storm water is discharged to waters
of the state or to a storm sewer” (NR Code 216). Outfalls are further categorized
by 2 types – major and minor. A major outfall is essentially one that is large
in size and drains a large area of land. Minor outfalls are the remaining
outfalls of various sizes and drainage areas.
over 100 stormwater outfalls (19 of them are major). Outfalls get screened
every year during dry weather (at least 2 days after rainfall) to detect
Illicit Discharge. Read more about Illicit Discharge from a previous blog post. Half of major outfalls get screened
every year (2-year rotation) and 1/5 of minor outfalls are every year (5-year
rotation). The trickiest part of outfall screening is FINDING the outfall. All
outfalls have been mapped many years ago, but the terrain has changed since
then . . . especially after the 2012 flood. Minor outfalls can be small (6” in
diameter) and can be buried underground.Outfalls should be dry during periods of no rain so any flow from an
outfall could potentially be an illicit discharge. In this past 2014 field
season we did observe flow from outfalls, but they were all likely due to
infiltration from natural water source or tap irrigation. Fortunately we didn’t
notice any odd discharge.
if you noticed two strange people parked along the side of the road, looking in the
nearby fields or staring at the storm drain off the road during the summer . .
. they may be trying to find the outfall in the field or off the road.