Green Roofs - Living Architecture Monitor - Summer 2017 - 14

TECHNICAL DISPLAY

HOW GREEN ROOF LAYERS
MANAGE STORMWATER
By Rohan Lilauwala, GRP

The many layers of green roofs work together to effectively manage stormwater in three important ways:
by retaining water, by delaying runoff from the roof, and by slowing the flow of runoff. For more information
on the work being done by the Green Infrastructure Foundation to establish standards for stormwater
performance, and to read a white paper on the subject, visit greeninfrastructurefoundation.org/lapt

VEGETATION

Evapotranspiration 'recharges' water
holding capacity of green roof

Green roof vegetation manages stormwater
in many ways. Plants evapotranspire, taking
up water from the growing media and
releasing it as vapor through stomata in
their leaves. Leaves intercept water before
it hits the growing media - this water is
also evaporated from their leaves. Plants
like sedums can hold water, expanding their
volume in the process.

GROWING MEDIA
Green roof growing media is specifically
engineered to be lightweight with large
pore space for maximum water holding
capacity. Once the growing media is
saturated, water is slowed as it travels
through this layer. Growing media additives
can further increase water holding capacity.
Growing media is arguably the most
important layer for water retention.

WATER RETENTION LAYERS
Runoff can be directed to a cistern on
or off the roof and be used for irrigation

Water retention layers can come in many
shapes and sizes, and includes fleece fabrics,
plastic trays/cups, aggregate, or mineral
wool. The purpose of each type is to retain
additional water for future plant use.

OTHER FEATURES

Image courtesy: Jeffrey L. Bruce & Company
LIVING ARCHITECTURE MONITOR / SUMMER 2017 / 14

Green roof drainage layers also come in
many shapes and sizes and slow and delay
the path of excess water draining from the
roof. Berms, edging, weirs, and other roof
features can also further slow water.
LIVINGARCHITECTUREMONITOR.COM


http://www.greeninfrastructurefoundation.org/lapt http://www.LIVINGARCHITECTUREMONITOR.COM

Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Summer 2017

Green Roofs - Living Architecture Monitor - Summer 2017 - Intro
Green Roofs - Living Architecture Monitor - Summer 2017 - Cover1
Green Roofs - Living Architecture Monitor - Summer 2017 - Cover2
Green Roofs - Living Architecture Monitor - Summer 2017 - TOC
Green Roofs - Living Architecture Monitor - Summer 2017 - A
Green Roofs - Living Architecture Monitor - Summer 2017 - 1
Green Roofs - Living Architecture Monitor - Summer 2017 - 2
Green Roofs - Living Architecture Monitor - Summer 2017 - 3
Green Roofs - Living Architecture Monitor - Summer 2017 - 4
Green Roofs - Living Architecture Monitor - Summer 2017 - 5
Green Roofs - Living Architecture Monitor - Summer 2017 - 6
Green Roofs - Living Architecture Monitor - Summer 2017 - 7
Green Roofs - Living Architecture Monitor - Summer 2017 - 8
Green Roofs - Living Architecture Monitor - Summer 2017 - 9
Green Roofs - Living Architecture Monitor - Summer 2017 - 10
Green Roofs - Living Architecture Monitor - Summer 2017 - 11
Green Roofs - Living Architecture Monitor - Summer 2017 - 12
Green Roofs - Living Architecture Monitor - Summer 2017 - 13
Green Roofs - Living Architecture Monitor - Summer 2017 - 14
Green Roofs - Living Architecture Monitor - Summer 2017 - 15
Green Roofs - Living Architecture Monitor - Summer 2017 - 16
Green Roofs - Living Architecture Monitor - Summer 2017 - 17
Green Roofs - Living Architecture Monitor - Summer 2017 - 18
Green Roofs - Living Architecture Monitor - Summer 2017 - 19
Green Roofs - Living Architecture Monitor - Summer 2017 - 20
Green Roofs - Living Architecture Monitor - Summer 2017 - 21
Green Roofs - Living Architecture Monitor - Summer 2017 - 22
Green Roofs - Living Architecture Monitor - Summer 2017 - 23
Green Roofs - Living Architecture Monitor - Summer 2017 - 24
Green Roofs - Living Architecture Monitor - Summer 2017 - 25
Green Roofs - Living Architecture Monitor - Summer 2017 - 26
Green Roofs - Living Architecture Monitor - Summer 2017 - 27
Green Roofs - Living Architecture Monitor - Summer 2017 - 28
Green Roofs - Living Architecture Monitor - Summer 2017 - 29
Green Roofs - Living Architecture Monitor - Summer 2017 - 30
Green Roofs - Living Architecture Monitor - Summer 2017 - 31
Green Roofs - Living Architecture Monitor - Summer 2017 - 32
Green Roofs - Living Architecture Monitor - Summer 2017 - 33
Green Roofs - Living Architecture Monitor - Summer 2017 - 34
Green Roofs - Living Architecture Monitor - Summer 2017 - Cover3
Green Roofs - Living Architecture Monitor - Summer 2017 - Cover4
Green Roofs - Living Architecture Monitor - Summer 2017 - M1
Green Roofs - Living Architecture Monitor - Summer 2017 - AD1
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https://www.nxtbook.com/dawson/greenroofs/lam_2019Fall
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https://www.nxtbook.com/dawson/greenroofs/lam_2019Spring
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https://www.nxtbook.com/dawson/greenroofs/lam_2018spring
https://www.nxtbook.com/dawson/greenroofs/lam_2017winter
https://www.nxtbook.com/dawson/greenroofs/lam_2017fall
https://www.nxtbook.com/dawson/greenroofs/lam_2017summer
https://www.nxtbook.com/dawson/greenroofs/lam_2017Spring
https://www.nxtbook.com/dawson/greenroofs/lam_2016winter
https://www.nxtbook.com/dawson/greenroofs/lam_2016fall
https://www.nxtbook.com/dawson/greenroofs/lam_2016summer
https://www.nxtbook.com/dawson/greenroofs/lam_2016spring
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https://www.nxtbook.com/dawson/greenroofs/lam_2015summer
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https://www.nxtbook.com/dawson/greenroofs/lam_2014winter
https://www.nxtbook.com/dawson/greenroofs/lam_2014fall
https://www.nxtbook.com/dawson/greenroofs/lam_2014summer
https://www.nxtbook.com/dawson/greenroofs/lam_2014spring
https://www.nxtbook.com/dawson/greenroofs/lam_2013winter
https://www.nxtbook.com/dawson/greenroofs/lam_2013fall
https://www.nxtbook.com/dawson/greenroofs/lam_2013summer
https://www.nxtbook.com/dawson/greenroofs/lam_2013spring
https://www.nxtbook.com/dawson/greenroofs/lam_2012fall
https://www.nxtbook.com/dawson/greenroofs/lam_2012summer
https://www.nxtbook.com/dawson/greenroofs/lam_2012spring
https://www.nxtbook.com/dawson/greenroofs/lam_2012winter
https://www.nxtbook.com/dawson/greenroofs/lam_2011fall
https://www.nxtbook.com/dawson/greenroofs/lam_2011summer
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https://www.nxtbook.com/dawson/greenroofs/lam_2011winter
https://www.nxtbook.com/dawson/greenroofs/lam_2010fall
https://www.nxtbook.com/dawson/greenroofs/lam_2010summer
https://www.nxtbook.com/dawson/greenroofs/lam_2010spring
https://www.nxtbook.com/dawson/greenroofs/lam_2010winter
https://www.nxtbook.com/dawson/greenroofs/lam_2009fall
https://www.nxtbook.com/dawson/greenroofs/lam_2009summer
https://www.nxtbook.com/dawson/greenroofs/lam_2009spring
https://www.nxtbook.com/dawson/greenroofs/lam_2009winter
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