How many gallons of water falls
on the school roof during a rain event?
The water has to go somewhere and with impervious surfaces it doesn't You could extend it into how many rain barrels (55 gallons) would fill.
Here are the area measurements for the local school buildings:
Lake Superior Elementary 38,603 square feet.
Great Lakes Elementary 40,308 sq ft
Cooper Elementary 63,438 sq ft
Bryant Elementary 39,783 sq ft
Northern Lights Elementary 109,466 sq ft
Four Corners Elementary 38,594 sq ft
Cathedral School 20,429 sq ft
Maranatha Academy 18,540 sq ft
Superior Middle School 245,785 sq ft
Superior High School 148, 989 sq ft
WITC 327,970 sq ft
UWS - Swenson Hall 47.623 sq ft
From this impervous surface you can determine how much water would fall on the roof in a given storm. It needs to go SOMEWHERE. The above measurements are for the building. Other parts of the school grounds - parking lots, sidewalks, and even ball fields are also impervious areas (where water doesn't soak in).
The USGS website let's you enter an area (feet x feet) and then enter a rain fall (1 inch, 1/2 inch, etc). It will give you how many gallons of water would fall.
The database wants to you enter a number of feet times a number of feet (or acres or sq miles)
Example: Here is a way to input the information.
Lake Superior Elementary 38,603 sq ft
Entered in as 10 X 3860
In a 0.5 inch rain storm this would lead to
12,031 gallons of water
That would fill about 219 rain barrels (55 gallon size)!
Here are aerial maps - with stormdrains. The GREEN dots are storm drains that go directly to a local stream. The RED dots are part of the city's combined sewer and the contents that go in those drains do come to the wastewater treatment plant for cleaning. Meanwhile, we want ALL street drains kept clear - and for people not to put inappropriate materials down toilets or sink drains either.
Here are a few more places in Superior and their building's area.
Walmart 216,474 sq ft
Mariner Mall 327,970
Superior Library 34,990
An average house ~1900 sq ft
Here are some resources teachers may be interested:
Coloring and info pages on the water cycle