1. Rain Gardens
& Bioswales
By Tom Barrett
Green Water Infrastructure, Inc.
www.ThinkGWI.com
Follow us on Twitter @TomBarrett_GWI
Tom.Barrett@ThinkGWI.com
© 2011 Tom Barrett

2. The GREEN
Economy

3. How Much Rain Falls in Chicago?
January
-
1.86" Image of Rain Falling
February
-
1.58"
March
-
2.59"
April
-
3.28"
May
-
3.75"
June
-
4.08"
July
-
3.39"
August
-
3.38"
September
-
2.91"
October
- 2.65"
November
-
2.09"
December
-
1.88"
Total
33.44"

4. How Much Water Falls in Chicago?
2,500 sq. ft. Roof
January
-
,727 gallons
2 Image of Rain Falling
February
-
,540
2
March
-
,130
4
April
- 5,735
May
-
,268
5
June
-
5,657
July
-
,470
5
August
-
,200
7
September
-
,096
5
October
-
,223
4
November
-
4,691
December
- 3,787
Total
6,525
5

5. How Much Water Falls in Chicago?
3 Acre Commercial Property
January
-
42,560 gallons
1 Image of Rain Falling
February
-
32,784
1
March
-
15,876
2
April
- 299,783
May
-
75,344
2
June
-
295,710
July
-
85,934
2
August
-
76,358
3
September
-
66,383
2
October
-
20,764
2
November
-
245,203
December
- 197,954
Total
2,954,654

6. How Much Water Falls in Chicago?
City Block
(660’ x 660’ – 10 acres)
January
-
75,195 gallons
4
February
-
42,610
4
March
-
19,581
7
April
- 999,267
May
-
17,805
9
June
-
985,690
July
-
53,105
9
August
-
,254,515
1
September
-
87,936
8
October
-
35,873
7
November
-
817,335
December
- 659,842
Total
9,848,756

7. Low Impact Site Development

8. Stormwater Mitigation
Stormwater Mitigation
Stormwater Mitigation
Stormwater Mitigation
Stormwater Mitigation

10. Peak Flow
(2,500 ft. sq. Roof)
Grass Field Roof
1 Year Storm 36 gpm 111 gpm
2 Year Storm 54 gpm 139 gpm
10 Year Storm 111 gpm 206 gpm
25 Year Storm 147 gpm 245 gpm
100 Year Storm 206 gpm 309 gpm
gpm – gallons per minute

11. Peak Flow
(1 Acre Site)
Grass Field Roof
1 Year Storm 630 gpm 1,932 gpm
2 Year Storm 942 gpm 2,424 gpm
10 Year Storm 1,932 gpm 3,588 gpm
25 Year Storm 2,556 gpm 4,266 gpm
100 Year Storm 3,588 gpm 5,388 gpm
gpm – gallons per minute

12. Change in Peak Runoff Flow Before and after Development
300%
225%
150%
75%
0%
m m m m m
S tor S tor S tor S tor S tor
ar r r r r
Ye ea Ye
a
Ye
a
Ye
a
1 2Y 10 25 0
10
Stormwater Effects of Urbanization

14. Image of Rain Falling

15. Pesticide Issues
Atrazine, Nitrogen, Phosphorous

16. Stormwater Mitigation
– Collection runoff near the
source
– Slow it down
– Soak it in
– Filter it
– Apply it to the landscape
– Create habitats

17. Simple Rain garden

18. Bioswales
Engineered Soils
Underdrain

19. Location
Plant Choices Rain gardens are often
located at the end of
a roof or drain spout.
Choose plants based on
the need for light and
soil type.
Depth Size Soil
A Rain Garden usually A tpical mix is 65%
A typical Rain Garden
five to ten percent of sand, 15% top soil,
is between four to
the impervious surface 25% organic matter.
eight inches deep.
area.
Rain Gardens

20. Rain Garden

21. Bioswales
Burnsville, Minnesota

22. Native Vegetation
www.epa.gov/greenacres/ www.for-wild.org

23. Street Edges
& Medians

24. Parking Lot
Edges

25. Parking Lot
Islands

26. Driveway
Edge

27. Neighborhoods

28. Rain Garden
Indianapolis

29. Rain Garden
Indianapolis - Fall Creek Parkway

32. Functional Landscapes

34. Thank You