A

Watershed

Approach

to

StormwaterBy Tom Barrett Green Water Infrastructure, Inc.www.ThinkGWI.comTom.Barrett@ThinkGWI.com

Follow us on Twitter @TomBarrett_GWI

© 2014 Tom Barrett

Green • Water • Infrastructure

Green • Water • Infrastructure

Green • Water • Infrastructure

Green • Water • Infrastructure

Green • Water • Infrastructure

Green • Infrastructure

The Future – incorporates the latest in scientific thinking

It’s Clean – more complete filtration

It’s Lean – less expensive

It’s Green – more natural, mimicking nature

In nature there is no good or bad;

there are only consequences.

Pre-Development Water Cycle

How Much Rain Falls in Chicago?

January  -  1.50"February  -  1.23"March -   2.40"April -    3.21"May -    3.93"June -   5.06"July -    3.42"August -    3.77"September -   3.15" October -   2.44"November -   1.95"December -   1.55"Total 33.61"

Image of Rain Falling

How Much Water Falls in Chicago?

January  -    2,338 gallonsFebruary  -    1,917March -    3,740April -    5,003May -    6,125June -     7,886July -    5,330August -    5,875September-    4,909October -     3,803November -     3,039December -    2,431Total     52,394

Image of Rain Falling

2,500 sq. ft. Roof

How Much Water Falls in Chicago?

January  -    10,183 gallonsFebruary  -    8,350March -    16,292April -    21,791May -    26,679June -     34,350July -    23,217August -    25,593September -    21,384 October -     16,564November -     13,238December -    10,590Total     248,229

Image of Rain Falling

¼ Acre Residential Property

How Much Water Falls in Chicago?

January  -    11,880 gallonsFebruary  -    11,065March -    17,990April -    24,982May -    22,945June -     24,642July -    23,828August -    31,363September -    22,199 October -     18,397November -     20,434December -    16,496Total     246,221

Image of Rain Falling

¼ Acre Residential Property

How Much Water Falls in Chicago?

January  -    142,560 gallonsFebruary  -    132,784March -    215,876April -    299,783May -    275,344June -     295,710July -    285,934August -    376,358September -    266,383 October -     220,764November -     245,203December -    197,954Total   2,954,654

Image of Rain Falling

3 Acre Commercial Property

How Much Water Falls in Chicago?

January  -    475,195 gallonsFebruary  -    442,610March -    719,581April -    999,267May -    917,805June -     985,690July -    953,105August -  1,254,515September -    887,936 October -     735,873November -     817,335December -    659,842Total   9,848,756

City Block (660’ x 660’ – 10 acres)

How Much Water is in Rain Event?¼” Rain ½” Rain 1” Rain

2,500 ft. sq. Roof

390 gallons 779 gallons 1,558 gallons

¼ Acre Residential Property

1,697 3,994 67,789

3 Acre Commercial Property

20,366 40,731 135,770

Chicago City Block

67,885 135,770 271,540

How Much Water Falls Fairfield, Iowa?

1” Rainfall on 2,300 Acres = 62,454,200 gallons

How Much Water Falls in Jefferson County?

1” Rainfall on 437 Square Miles (279,680 acres)

7,594,430,720 Gallons (7.6 billion)

Stormwater Mitigation

Stormwater Mitigation

Stormwater Mitigation

Stormwater Mitigation

Stormwater Mitigation

Stormwater Effects of Urbanization

Change in Peak Runoff FlowBefore and after Development

0%

50%

100%

150%

200%

250%

1 Year Storm 2 Year Storm 10 YearStorm

25 YearStorm

100 YearStorm

Peak Flow(2,500 sq. ft. Roof)

Grass Field Roof

1 Year Storm 0.08 cfs 0.25 cfs

2 Year Storm 0.12 cfs 0.31 cfs

10 Year Storm 0.25 cfs 0.46 cfs

25 Year Storm 0.33 cfs 0.55 cfs

100 Year Storm 0.46 cfs 0.69 cfs

cfs – cubic feet per second

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

Peak Flow(1 Acre Site)

Grass Field Roof

1 Year Storm 1.4 cfs 4.3 cfs

2 Year Storm 2.1 cfs 5.4 cfs

10 Year Storm 4.3 cfs 8.0 cfs

25 Year Storm 5.7 cfs 9.5 cfs

100 Year Storm 8.0 cfs 12.0 cfs

cfs – cubic feet per second

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

• Image of Rain Falling

Pesticide Issues

• Atrazine, Nitrogen, Phosphorous

Atrizene

Low Impact Site Development

Stormwater Mitigation

– Collection runoff near the source

– Slow it down

– Soak it in

– Filter it

– Apply it to the landscape

– Create habitats

Green • Infrastructure

The Future – incorporates the latest in scientific thinking

It’s Clean – more complete filtration

It’s Lean – less expensive

It’s Green – more natural, mimicking nature

Watershed Approach

Watershed Approach

Watershed Approach

Watershed Approach

Watershed Approach

Windridge RavineComprehensive Drainage Study

• Site Inspection

1. Evaluate the Watershed Basins

2. Complete an on-site evaluation

3. Identify problems

4. Identify potential solutions

7. Prioritize Solutions

Green • Infrastructure

The Future – incorporates the latest in scientific thinking

It’s Clean – more complete filtration

It’s Lean – less expensive

It’s Green – more natural, mimicking nature

It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.

- Charles Darwin