Neighbourhood Stormwater Storage Space
Helping Meet Vancouver’s Water Conservation Target
Lukas Holy, B.Sc., MLA Candidate
ABSTRACT This case study examines how much
space would be needed in order to collect enough
stormwater to meet the irrigation needs of ground level
green roofs within an urban watershed in Vancouver,
BC. Stormwater harvesting is presented as a method
for water conservation that has the potential to help
meet Vancouver’s water conservation objectives.
Specifically, goal eight of Vancouver’s Greenest City
Action Plan stipulates a reduction in per capita water
use by 33% from 2006 levels. The results indicate that
a public open space adjacent to the urban watershed
studied provides adequate space to store enough
stormwater to meet the irrigation need of ground level
green roofs within that watershed. Furthermore, this
water infrastructure is similar in scale to that which
already exists on the site.
INTRODUCTION
In recent years, Vancouver has taken steps to ensure
that the high quality of life enjoyed by its residents
is maintained for future generations. The Greenest
City Action Plan is one such initiative with the goal
of helping Vancouver become the “Greenest” city by
2020. Within this ten point plan, goal eight specifies
the provision of clean water for all residents of
Vancouver, addressing both issues of water quality
and water consumption (COV, 2012). Currently,
Vancouver enjoys some of the best quality drinking
water in the world in which mountain reservoirs in
protected and undeveloped watersheds supply the city
with drinkable water (Welsh, 2011).
While issues of water quality have largely been
addressed, the future availability of water is in
question. Climate change research shows that a 15%
decrease in snowpack throughout BC can be expected
by 2050 and a 25% decrease by 2080 (Cohen et. al,
2010, Columbia Basin Trust). Located in the North
Shore mountains, Vancouver’s reservoir levels are
largely driven by winter snowpack accumulation.
Consequently, a decrease in North Shore mountain
snowpack will have detrimental effect on the supply of
potable water in Vancouver. Furthermore, the demand
for potable water is expected to increase as migration
to Vancouver grows. Some estimates predict
that as many as 40 million to 700 million people will
move to Vancouver as a result of the climate change
displacement (Welsh, 2011).
To address the simultaneous decrease in supply
and increase in demand for water in Vancouver,
the Greenest City Action plan calls for a water
conservation target by 2020 of a 33% decrease in
per capita potable water use below 2006 levels. The
measures that have already been introduced include
summertime outdoor watering education, water
metering, and a mandate to install low flow fixtures
in all new construction (Welsh, 2011). However, this
effort is expected to fall short of the 2020 target by
approximately 12%, meaning further consumption
reductions will have to be addressed through new and
innovative methods.
Residential water use accounts for over half of the
water consumed in the city of Vancouver (Welsh,
2011). During the summer months, 30% of this
residential water consumption is a result of landscape
irrigation (Welsh, 2011). Thus, limiting the use of
potable water for landscape irrigation has the potential
to have a significant impact on per capita water
consumption. While Metro Vancouver acknowledges
the role of rainwater and wastewater harvesting
in achieving the city’s water conservation targets,
municipal bylaws stand in the way of any such scheme
(DWMP, 2011). The Metro Vancouver Drinking
Water Management Plan does, however, suggest that
such bylaws should be reviewed and that alternatives
to potable water should be considered for in-ground
irrigation systems (DWMP, 2011).
ALTERNATIVE SOLUTIONS FOR IRRIGATION
A large fraction of the potable water consumption in
Vancouver’s downtown residential neighbourhoods is
the result of ground level green roof irrigation. Green
roofs of this kind have traditionally served to increase
1
the
amount
accessiblehealth
open and
space
within the
dense
required
forofgreenroof
function
(Roehr
downtown core. Increasingly, they are also being
and Kong, 2010). Vancouver’s climate necessitates a
designed to take on the role of green infrastructure,
significant input
of water
maintain the
health of
performing
as systems
for to
stormwater
mitigation
greenroofs
summer the
dry season
(Roehr
and
wildlifethroughout
habitat (Oberndorfer,
2007).
Whatever
the
function,
success
of a greenroof
is roofs
anddesired
Kong, 2010).
Asthe
a result,
ground
level green
dependent
the health
of the on
plant
material
of which
represent aon
significant
burden
water
consumption
it is composed. Vancouver’s climate necessitates a
in Vancouver’s
order for
significant
inputdowntown.
of water toIn
maintain
theVancouver
health of
to
decrease
its
per
capita
water
consumption,
green
green roof plabt material throughout the dry summer
season
(Roehr
andto
Kong,
2010). Asso
a result,
ground
roof design
needs
be optimized
that less
level
green
roofs
representtoa maintain
significantroof
burden
on
potable
water
is required
health
water consumption in Vancouver’s downtown.
and function. Design of a green roof system which
utilizes
precipitation
insteadits
ofper
potable
In
orderwinter
for Vancouver
to decrease
capitawater
water
consumption,
green roof
design
needsmeeting
to be optimized
would help Vancouver
move
towards
its water
so
that less potable
water is required to maintain roof
conservation
targets.
health and function. Design of a green roof system
which utilizes winter precipitation instead of potable
Throughout
mostVancouver
of the yearmove
watertowards
is a ubiquitous
water
would help
meeting
entity
in
the
city
of
Vancouver.
The
average
annual
its water conservation targets.
precipitation depth in the city is a generous 1300mm
Throughout
most
the yearfrom
watera is
a ubiquitous
(CCN, 2012).
Theofproblem
water
conservation
entity in the city of Vancouver. The average annual
perspective isdepth
that precipitation
precipitation
in the city is accumulation
a generous 1300mm
in
Vancouver
is
spread
unevenly
the
(CCN, 2012). The problem from athroughout
water conservation
perspective
is that precipitation
is
year. Paradoxically
the summer,accumulation
the season when
spread
unevenly
throughout
the
year.
The
summer,
green roofs require the most water, sees very little
when green roofs require the most water, sees very
precipitation accumulation at all (Figure 1). To make
little precipitation accumulation at all (Figure 1). To
rainwater
available
for consumption
throughout
the
make
rainwater
available
for consumption
throughout
the
design
challenge
to collect
yearyear,
the the
design
challenge
is toiscollect
andand
storestore
water
as
a
neighbourhood
scale
rainwater
collection
system.
water
thatinfalls
the winter
on green
that falls
thein
winter
for useforonuse
green
roofs roofs
in thein
the
summer.
Currently
downtown
Vancouver
is being
summer. rainwater
Given the in
abundant
rainfall
in Vancouver,
collected,
but not effectively
utilized.
the city’s
is adept
at quickly the
moving
Given
theinfrastructure
abundant rainfall
in Vancouver,
The use
of Vancouver’s
stormwater
may where
be answer to
large
volumes
of water
away
areas
city’s
infrastructure
is adept
atfrom
quickly
moving it
the
water
need
ground
large
volumes of
water
away exhibited
from areas
where
it level
is anon-potable
nuisance.
An
extensive
network
ofbydedicated
is
a nuisance.
Anpresent
extensive
network
of dedicated
green
roofs. The
research
seeks
to identify
stormwater
sewers
that
collect
rainwater
of in
the irrigation need of ground level green off
roofs
impervious surfaces exist throughout large parts of
one drainage basin area in downtown Vancouver.
the downtown peninsula (COV, 2010) (Figure 2).
Subsequently
this paper will
identify
the volume
These
sewers concentrate
runoff
in specific
areas of
stormwater, downtown
which moves
thethis
same
throughout
andthrough
organize
partarea.
of the
city
into
a
patchwork
of
drainage
basins.
The
sewers
Finally the paper will explore how the proximity of
that make up these drainage basins effectively serve
greenroof water need to stormwater source can be
as a neighbourhood scale rainwater collection system.
organized rainwater
into a system
that will help
reduce the
Currently
in downtown
Vancouver
is being
amount ofbut
potable
water needed
for irrigation.
collected,
not effectively
utilized.
A
B
Figure 1. Green roofs require irrigation in the summer dry
season (A) While they help mitigate stormwater in
the winter wet season (B)
stormwater sewers that collect rainwater off of
impervious surfaces exist throughout large parts of
the downtown peninsula (COV, 2010) (Figure 2).
These sewers concentrate runoff in specific areas
throughout downtown and organize this part of the
city into a patchwork of drainage basins. The sewers
that make up these drainage basins effectively serve
Lukas Holy
3
Figure 2. Stormwater sewer network in downtown
Vancouver. Site boundary is outlined in red.
2
the
o
he
oset
d
et
Figure 5. Groundcover and Shrubs
Kc 0.58
H
H
a
ar
w
w ofrresearch
by the limitation
resources allocated for
study were found exclusively on top of residential
oo
oo
by the limitationdof
research
resources allocated for
study were found exclusively on top of residential
d
this study. The siteSt was picked
due to its abundance of
parking garages.
St
this study. The site was picked due to its abundance of
parking garages.
Figure
5. Groundcover and Shrubs
accessible ground level green roofs, its modest
size and
accessible ground level green roofs, its modest size and K 0.58
because of its proximity to a large public open space.
c Green roof typologies were identified based on the
because of its proximity to a large public open space.
Green roof typologies were identified based on the
An inventory of ground level green roofs was
type of plant material to which they played host. The
An inventory of ground level green roofs was
type of plant material to which they played host. The
undertaken within the study area. This study defines
green roof types identified within this study were
undertaken within the study area. This study defines
green roof types identified within this study were
ground level green roofs as any landscaped areas that
as follows: turfgrass, groundcover and shrubs, trees
ground level green roofs as any
landscaped
areas
that
as follows: turfgrass, groundcover and shrubs, trees
e
can be visually identifiedidas
shrubs and groundcover, trees shrubs and turfgrass
g existing on top of a built
r
can be visually identified
on top of a built
shrubs and groundcover, trees shrubs and turfgrass
d B as existing identified
e
structure. Groundurlevel
by
this
(Figure 4,5,6,7) The crop coefficient method, as
rar green roofs
dg
B level green roofs
Bri identified by this
structure. Ground
(Figure
4,5,6,7) The crop coefficient method, as
d
r
rra
u
B
Lukas Holy
5
Figure
e
Av
ch
ard
c
ea
rard
Figure 4. Turfgrass - Kc 0.75
B
e
Av
ch
hh
Figure 4. Turfgrass - Kc 0.75
c
a
Be
in
n
rea.
ea.
c
t
to
vel
Green roof typologies were identified based on the
type of plant material to which they played host. The
green roof types identified within this study were as
follows:
• turfgrass
• groundcover and shrubs
• trees shrubs and groundcover
• trees shrubs and turfgrass
(Figure 4,5,6,7)
c
i
el
With the help of maps provided by the City of
Figure 4. Turfgrass - K 0.75
Vancouver’s Department ofFigure
Engineering
4. Turfgrass -and
K 0.75
Vancouver Police Departmen,t an urban watershed
in downtown Vancouver was identified as the study
area. It is bordered by Jervis Street, the north side
of Harwood Street, Beach Avenue and the Burrard
Street Bridge. Stormwater within this watershed is
concentrated at the foot of Jervis street where it is
picked up buy Jervis Forcemain No. 2 or allowed to
spill into False Creek. Residential towers populate the
site with construction that ranges from the 1960’s to
the present day. To the south-west of the site is Sunset
Beach Municipal Park. The site was picked due to
its abundance of accessible ground level green roofs,
its modest size, and its proximity to a large public
Figure
5. Groundcover
and Shrubs
open space. An inventory ofFigure
ground
level green
roofs
5. Groundcover
and Shrubs
K 0.58
Figure 2. Stormwater sewer network
in downtown
was undertaken, being defined as Kany
landscaped
0.58
Vancouver.
Site boundary
is outlined
in red.
Figure
2.
Stormwater
sewer
network
in
downtown
areas that can be visually identified as existing on
Vancouver. Site boundary is outlined in red.
top of a built structure. In this case, they were found
exclusively on top of residential parking garages.
Je s St
rv
is
S
em.
to
ng
The use of stormwater to meet irrigation needs
on ground level green roofs may be the answer to
meeting Vancouver’s water conservation targets.
The present research seeks to identify the irrigation
need of ground level green roofs in a single drainage
basin in downtown Vancouver as well as the volume
of stormwater which moves through the same area
in order to explore how the proximity of green roof
water need to stormwater source can be organized
into a holistic water recycling system.
Je
rv
m.
ng
SITE INVESTIGATION
Figure 3. Study site with adjacent municipal park
Figure 3. Study site with adjacent municipal park
Lukas
Holy
by the limitation of research resources
allocated
for
Figure 6. Trees, Shrubs, and groundcover
this study. TheGroundcover
site was picked
due to its abundance of
- K c 0.52
accessible ground level green roofs, its modest size and
5study
we
parking
3
of irrigation needed during the dry months is
calculated by subtracting the monthly precipitation
from monthly irrigation during the dry months
(Table 2). Adding the above values together yields the
Figure
Trees, Shrubs
and Turfrequired to irrigate all ground
total 7.volume
of water
K 0.5
level green roofs within the study site. The resulting
total volume of water necessary for irrigation of all
greenroofs within the study site is 168 000 liters.
c
Depth (mm)
Figure 7. Trees, Shrubs and Turf
K c 0.5
Graph 1. Percipitation crosses with
irrigation curves. This shows
the time of year when the
described by (Allan et al., 1998) was used to calculate
Green
irrigation is
higherRoof
than Crop Coefficient Formula:
evapotranspiration of greenroofs identified within percipitation
ET = K x ET
METHODOLOGY
CG
Depth (mm)
CG
The crop coefficient method, as described by (Allan
O
Depth (mm)
Depth (mm)
the study area. Crop coefficients
for
each plant type
1. Percipitation
crosses with
et al., 1998) was usedGraph
to calculate
evapotranspiration
(KC) identified on site, were taken from
information
Green roof evapotranspiration rates, (ET
) were
irrigation
curves. This shows
CG
Months
of green roofs identified within
the study
area.
Green
the
time
of
year
when
the
presented by the British Columbia Ministry of
calculated using a reference evapotranspiration rate,
roof evapotranspiration rates,
(ETCG)
were than
calculated
irrigation
is higher
Graph
Percipitation
crosses
with
Agriculture, Food and Fisheries (Van
der Gulik, 2001). (ETO) as described
by the1.British
Columbia
Ministry
percipitation
using a reference evapotranspiration
rate, (ETO)
irrigation curves. This shows
KC were averaged to derive a representative crop
of Agriculture, Food and Fisheries (Van der Gulik,
the time of year when the
as described by the British Columbia Ministry of
2002). ETO is the pan evapotranspiration
or reference
coefficient for each greenroof type (KCG).
irrigation is higher
than
Agriculture, Food and Fisheries (Van der Gulik, 2002).
1.percipitation
Percipitation
crosses
ET for vegetation.Graph
The purpose
for estimating
the with
Months
irrigation
curves. This shows
Figure 8. Size of neighbourhood
ground level green roof
the time of year when the
To
convert
the
ETCG
to
the
green
roof
irrigation
Neighbourhood Stormwater Storage Space
6
irrigation is higher than
Roof Crop
Coefficient
Formula:
requirement
(IRG)
a conversion factor which takes
percipitation
Mon
into account the irrigation system efficiency is often
KCG x ET
O
applied (Van der Gulik, 2001). However, irrigation
system efficiency should be determined by actual field
roof evapotranspiration
rates,was
(ETnot
) were
thein
rational
method to the total site area.
could theoretically be stored at a neighbourhood
Mo
CG applying
measurements which
possible
the present
Figure
8.
Size
of
neighbourhood
The
coefficient
of
runoff
used
for
this
calculation
is
collection
point
relatively
close
to
all
the
green
ated using
a
reference
evapotranspiration
rate,
study. For the purposes of the study, a hundred
ground
level green roof to a high density residential
roofs ( Figure 8). Sunset Beach Park is located in an
.75, which
percent
efficiency
assumed
and ancorresponds
irrigation
as described
by the
Britishwas
Columbia
Ministry
area (LMNO, 2003). The total site area (A) is104580
ideal location to house the neighbourhood cistern
efficiency conversion factor was2 not applied.
iculture, Food and Fisheries (Van der m
Gulik,
and the rainfall intensity used in the calculation is
necessary to store enough stormwater to sustain the
Figure
8.
Size
of
neighbourhood
1.288m/
year.
The
yearly
runoff
volume
produced
by
green
roofs through the dry season (Figure 9).
ETO isThe
the pan
evapotranspiration
or to
reference
rational
method was used
estimate peak runoff
ground level green roof
the study area is approximately 101 024 000L of water.
vegetation.
Thegenerated
purpose for
estimating
theThe method used
volume
at the
study site.
The advantage of considering stormwater
was modeled after a similar technique
Discussion:employed by
harvesting
at the urban watershed scale is that the
neighbourhood
applying
rational the
method
to the
total site area.Figure 8. Size
couldoftheoretically
be stored at a neighbourhood
(Roehr and Kong,
2010).the
However
current
study
stormwater
collection
ground level green
roofsystem is already in place.
The coefficient
for
thisthere
calculation
is enough collection
point relatively
close
to allallthe
uses a rainfall intensity
(i) thatof
isrunoff
measured
in that
mm/
Study
resultsused
indicate
is more than
One neighbourhood
cistern
can collect
thegreen
irrigation
need (volume
of water)
.75,
corresponds
to athe
high
density
roofsstormwater
( Figurenecessary
8). Sunset
is located
runoff to feed
irrigation
needresidential
of ground level
for Beach
multiplePark
residences
at a lowin an
year as employed
bywhich
LMNO
engineering
(LMNO,
green
roofs
within
one
urban
watershed
in
downtown
point
in
the
drainage
basin.
As
a
result,
storage
and
2003).
area (LMNO, 2003). The total site area (A) is104580
location
to house
cistern
An estimateideal
of peak
yearly
runofftheofneighbourhood
the urban
Vancouver. The volume of stormwater
necessary
to rational
treatment
infrastructure
only need
toarea.
be constructed could th
applying
the
method
to
the
total
site
2
m and the rainfall intensity used in the calculation
is basin
necessary
to store enough
stormwater
sustain the
drainage
was calculated
by applying
the to
rational
perform irrigation functions within the drainage basin
once, and multiple households can benefit from
The method
coefficient
of runoff
used
for The
this
calculation
the
total
site
area.
coefficient
ofisrunoff
1.288m/ year. The yearly runoff volume produced
by to green
roofs
through
the dry
season (Figure
9). collectio
RESULTS
Lukas Holy
9
forcorresponds
this calculation
is .75,density
whichresidential
corresponds
.75,ofused
which
to a high
roofs ( F
the study area is approximately 101 024 000L
water.
applying
thedensity
rationalresidential
method toarea
the (LMNO,
total site 2003).
area.
could t
to
a
high
By comparing the monthly irrigation need and
The advantage
of site
considering
area (LMNO, 2003).
The total
area (A)stormwater
is104580
ideal loc
coefficient
runoff
is
collect
The
total siteofarea
(A) used
is104for
580this
m2calculation
and the rainfall
monthly precipitation, the time of year when potable The
2
Discussion:
harvesting
at the
urban
watershed
scale is
that the
m
and
the
rainfall
intensity
used
in
the
calculation
is
necessa
used in the calculation
is 1.288m/
year. The roofs (
water input is required was identified as July and
.75,intensity
which corresponds
to a high density
residential
stormwater
collection
system
is
already
year.
Thevolume
yearly runoff volume
produced
byin place.green ro
yearly
runoff
the
study
area
August, when irrigation need exceeds precipitation. 1.288m/
area
(LMNO,
2003). Theproduced
total site by
area
(A)
is104580
ideal lo
Studytherefore
results indicate
there
is more than
One
neighbourhood
cistern
canmore
collect
all the
is
approximately
101
024
000L
of
water,
than
(Graph 1) Irrigation
needsthat
to be
applied
theenough
study
area
is
approximately
101
024
000L
of
water.
2
and theto
rainfall
intensity
used
in
calculation
is at anecess
runoff
to feed
themonths.
irrigationThe
need
of ground m
level
stormwater
necessary
forthe
multiple
residences
low
enough
cover
the yearly
irrigation
need.
to the green roofs
during
these
volume
The adv
1.288m/
year.
The
yearly
runoff
volume
produced
by
green
r
green roofs within one urban watershed in downtown
point in the drainage basin. As a result, storage and
4
Discussion:
harvesti
the study
is approximately
101 024
Vancouver. The volume of stormwater necessary
to areatreatment
infrastructure
only000L
need of
to water.
be constructed
DISCUSSION
The results of this study indicate that there is more
than enough stormwater runoff during the rainy
season to feed the irrigation needs of ground level
green roofs through the dry season in Vancouver. The
Figure 9. Neighbourhood cistern in
volume of stormwater necessary
to site
perform
context irrigation
functions within a single urban drainage basin in
Figuretheoretically
9. Neighbourhood
cistern at
in a
the downtown could
be stored
site context
neighbourhood collection point relatively close to all
the green roofs in the same urban watershed. In this
case, that storage point is Sunset Beach Park (Figure
9). Vancouver’s low-lying waterfront green spaces
make ideal locations to store stormwater because they
are already the sites of neighbourhood outfalls.
Figure 9. Neighbourhood cistern in
site context
Figure 9. Neighbourhood cistern in
site context
The advantage of considering stormwater
harvesting at the urban watershed
is that
the
Figure 10. scale
Stormwater
pipes
that do not
culminate
in public open
stormwater collection system is already
in place.
space
One neighbourhood cistern can collect
all the
stormwater necessary for multiple residences at a low
Figurebasin.
10. Stormwater
pipesstorage
that do not
point in the drainage
As a result,
and
culminate in public open
treatment infrastructure only
spaceneed to be constructed
once, and multiple households
can benefit from one
one neighbourhood infrastructure project. The
neighbourhood infrastructure project.
area was chosen partly because of its proximity to a
neighbourhood approach to stormwater harvesting
large public open space that could easily accommobenefit is that it requires one specialized urban
date a neighbourhood stormwater cistern. Given the
There are, however, significant obstacles to the wide
Figure
10.
Stormwater
pipes thatinfrastructure
do not
intervention, which has the potential to service a local
fact that stormwater
of a similar volume
scale implementation of neighbourhood stormwater
culminate in public open
already
exists
within
the Sunset
Park
it is not beyond
and already
interconnected
clientele.
area was
chosen
partly
because
of its
proximity
to a
one neighbourhood
infrastructure
project.
The
Figure 10. Stormwater
pipes that do not
space
harvesting, especially when the technique is to be
the
realm
of
possibility
that
another
structure
of similargeculminate
public open
space open
that could easily accommoapproach neighbourhoods.
to stormwater harvesting
in public
implementedneighbourhood
in existing residential
scale could be added
(Figurecistern.
11). However
There
are however
obstacles
a lar
neighbourhood
stormwater
Givennot
theall
benefit isisthat
it requires
one significant
specialized
urban to the wide datespace
One major obstacle
stormwater
storage
space. While
urban drainages culminate in open space, therefore
scale implementation of neighbourhood stormwater
fact that stormwater infrastructure of a similar volume
intervention,
which
hasisthe
potential
to service a local
the cistern depicted
in this
study
modest
in size,
harvesting, especially when 2the technique is to be
stormwater storage placement would have to be careland in the city
expensive
and even the
60m cistern
already exists within the Sunset Park it is not beyond
andisalready
interconnected
clientele.
fully considered in areas of high density (Figure 10).
existing residential neighbourhoods.
footprint suggested hereimplemented
would be in
difficult
to situate.
the realm of possibility that another structure of simiA major basins
obstacle culminate
to implementing
harvesting
shemes
one neighbourhood
infrastructure project. The
area was
Furthermore,There
not all
in
lar scale
couldmajor
be added
(Figure
11). Howeverstormwater
not all
aredrainage
however
significant
obstacles
to the
wide
is
stormwater
storage
space.
While
the
cistern
depicted
Another
obstacle
to
neighbourhood
open space, making stormwater storage placement neighbourhood
approach
to
stormwater
harvesting
large
pub
CONCLUSION
neighbourhood
infrastructure
project.
area was
drainages
culminate
in finding
open The
space,
scale implementation
ofisneighbourhood
stormwater
in high
this study
modest
in size,
land
in one
the city
is ex- urbanharvesting
has
to do with
a way therefore
to distribute
more difficult in areas of
density
(Figure
10).
is that
it requires
one
specialized
urban
date a ne
2
stormwater
storage
placement
would
to be careharvesting, pensive
the60m
technique
tobenefit
be suggested
neighbourhood
approach
to stormwater
harvesting
andwhen
even the
cisternisfootprint
the stormwater
harvested.
A have
distribution
sys-large pub
Another major
obstacleespecially
to neighbourhood
stormwater
This study concludes
that being
neighbourhood
stormwater
intervention,
which
the
to service
a(Figure
localfrom
fact
fully
considered
inpotential
areas
high
density
10).the
implemented
in
existing
residential
neighbourhoods.
here
would
bea difficult
situate.
The present
study
tem has
would
have
to beofconstructed
benefit
is that
itschemes
requires
one
specialized
urban
datethat
a ne
harvesting has
to do with
finding
way to todistribute
harvesting
have
the
potential
to separately
significantly
and
already
interconnected
clientele.
already
A
major
obstacle
to
implementing
harvesting
shemes
Neighbourhood
Stormwater
Storage Space
10
the stormwater being harvested.
A distribution
system
reduce
potable
consumption,
intervention,
whichwater
has the
potential to thereby
service ahelping
local
fact thate
major obstacle
neighbourhood
stormwater
is be
stormwater
storage
space. While
cistern depicted
would have to
constructed
separately
fromthethe
the
realm
cityAnother
ointerconnected
f Vancouver
toclientele.
meettoits
water conservation
and the
already
already
e
potable waterindistribution
system
and
would
therefore
harvesting
has
to do obstacles
with
finding
waywide
distributelar scale
this study is modest in size, land in the city There
is ex-targets.
However,
it appears
water
scarcity
istonot
are however
significant
to athe
the realm
2
represent a significant
to implementing
a suggested
enoughthe
yetstormwater
acute enough
warrant A
thedistribution
significantsyscistern footprint
beingtoharvested.
pensive andchallenge
even the 60m
scale
implementation
of
neighbourhood
stormwater
urban
dr
There are however significant
obstacles to the
wide
lar scale
stormwater harvesting
Retrofit
stormwater
construction
of stormwater
here would scheme.
be difficult
to situate.
The present studycosts associated
tem wouldwith
havethe
to be
constructed separately
from the
harvesting,
especially
when
the techniquestormwater
is to be
stormwa
harvesting projects would be especially difficult to
projects.
scaleharvesting
implementation
of neighbourhood
urban dr
Neighbourhood
Stormwater
Storage
Space
10
construct for this reason.
implemented
in
existing
residential
neighbourhoods.
fully
con
harvesting, especially when the technique is to be
stormwa
A
major obstacle
to implementing
shemes
implemented
in existing
residentialharvesting
neighbourhoods.
fully con
is
stormwater
storage
space.
While
the
cistern
depicted
Another
A major obstacle to implementing harvesting shemes
in
this study isstorage
modestspace.
in size,
land the
in the
city is
exharvestin
is stormwater
While
cistern
depicted
Another
2
pensive
and
even
the
60m
cistern
footprint
suggested
the
storm
in this study is modest in size, land in the city is exharvestin
5
here
would
difficult
to situate.
presentsuggested
study
tem
wou
2
pensive
andbe
even
the 60m
cisternThe
footprint
the storm
view
ruary
Crop
op
e
tion
.
and
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6