Water sensitive urban design · Raingardens Above ground design A 100 mm to top of planter box B...

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www.watersensitivesa.com

WSUD in your home & backyard

Port Adelaide & EnfieldCommunity Environment Group

19 October 2017Mellissa Bradley, Program Manager


Water sensitive urban design

……. is an approach to urban planning and design that

integrates the management of the total water cycle into

the land use and development process

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Principles

• Re-integrate water back into urban landscape – create

microclimate

• Re-use of water at source (or close as possible)

• Protect receiving water quality (streams and marine)

• Fit for purpose water use


Content

▪ Urbanisation and changes to catchment hydrology

▪ Rainwater harvesting and re-use

▪ Infiltration systems

▪ Raingardens

▪ Vegetated swales

▪ Permeable paving

▪ What to consider if planning a new build

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Source: Coutts et al. (2012)

Reducing stormwater runoff

benefits water cycle

Urbanisation and changes to catchment hydrology

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Source: Centre for Water Sensitive Cities

Water on a hectare of forest over a year



Water on a hectare of forest over a year

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Replace the forest with a building




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Change to hydrograph


Allotment WSUD Solutions

▪ Collection and reuse of rainwater and stormwater on site

– onsite detention

– onsite retention

– rain gardens

– vegetated swales and buffer strips

– direction of flow from impervious ground surfaces to landscaped areas.

▪ Reduced impervious areas▪ site coverage

▪ permeable paving

▪ Water conservation

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Rainwater harvesting and re-use


Rainwater tank collection system

1. ROOF SURFACE condition

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1. SURFACE condition2. GUTTER MESH (6mm wire

mesh)



1. ROOF SURFACE condition 2. GUTTER MESH (6mm wire

mesh) 3. GUTTER OUTLETS4. RAIN HEADS. 5. FIRST FLUSH WATER

DIVERTERS. 6. TANK SCREEN7. WATER TANK SIZE. 8. INSECT PROOF SCREENS or

FLAP VALVES for TANK OVERFLOW OUTLETS.

9. TANK (MAINS) TOP UP10. PUMP SYSTEM11. FILTER

Source: John Caley_Ecological Design

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Factors in tank size selection

▪ Supply v demand

▪ Yields will be dependant on:

– annual rainfall

– roof area connected to tank

– Amount of and frequency of rainwater use:

• indoor (toilet, laundry, hot water service

• Outdoor (garden, “leaky tank”)

– Capacity of the tank connected to roof


Percentage of time rainwater tank will

meet full domestic internal daily demand

Assumptions: The internal water use estimates are based upon a 3 person household.

KENT TOWN

(Average Annual Rainfall 583 mm)

Rainwater Use

OptionHigh internal use

Medium internal use

1

Medium internal use

2Low grade uses

Description

11L single flush toilet,

100% laundry (front

load WM) & HWS

(6/3L) Dual flush

toilet, AAA-rated

shower head, 100%

laundry (top load WM)

& HWS

(6/3L) Dual flush

toilet, AAA-rated

shower head, 100%

laundry (front load

WM) & HWS

(6/3L) Dual flush toilet and

100% laundry (front load WM)

only

Tank Capacity

(L)1,000 2,000 5,000 1,000 2,000 5,000 1,000 2,000 5,000 1,000 2,000 5,000 9,000

Ro

of

are

a t

o b

e

co

nn

ec

ted

to

rain

wa

ter

tan

k (

m²) 50 9% 11% 11% 17% 19% 19% 23% 27% 28% 51% 59% 65% 68%

100 19% 26% 30% 30% 40% 47% 39% 50% 60% 65% 77% 87% 97%

150 25% 36% 46% 37% 50% 63% 47% 60% 72% 71% 83% 95% 100%

200 29% 42% 56% 41% 55% 70% 51% 65% 79% 74% 87% 98% 100%

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Supersize your rainwater tank

2,000L underdeck

2,000L slimline

Note: Prices are indicative only

Size (L) Material Min Max

1,000 L poly $385 $425

2,000 L poly $485 $1,750

5,000 L poly $730 $1,450

10,000L poly $1,280 $1,900

Size (L) Material Typical

1,000 L Galv. steel $860

2,000 L Galv. steel $1,025

5,000 L Galv. steel $1,450

10,000L Galv. steel $1,850

3,000L modular



mesh) 3. Gutter outlets4. Rain heads. 5. First flush water diverters. 6. Tank screen7. Water tank size. 8. Insect proof screens or flap

valves for tank overflow outlets.

9. Tank (mains) top up10. Pump system11. Filter

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1. Roof surface condition 2. Gutter mesh (6mm wire

mesh) 3. Gutter outlets4. Rain heads. 5. First flush water diverters. 6. Tank screen7. Water tank size. 8. Insect proof screens or flap

valves for tank overflow outlets.

9. Tank (mains) top up10. Pump system11. Filter

Source: www.rainharvesting.com.au

Typical cost: Plumbing (labour) $450-$800Pump system $500-$800Filter $400-1,000


Maintenance of water quality

• Clean gutters and

screens

• “Vacuum” sediments

from bottom of tank

• Replace filter cartridges

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Water conservation


Water Conservation

▪ Water efficient shower heads▪ Front loading washing machine▪ Tap aerators▪ Dual flush toilets▪ Re-use of grey water and

recycled water▪ Cold water diverters

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Tap aerators

reductionrevolution.com.au


Cold water diverters

Sends the cooled water to a predetermined area such as:

• Rainwater Tanks

• Swimming Pools

• Gardens or Garden Irrigation

• Toilet Cisterns

• Laundry Areas

• Livestock Drinking Water

redwater.net.au

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Onsite retention ofStormwater via infiltration


Infiltration trenches

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Restoring the balance in the urban water cycle


In-site retention – infiltration

systemsSuitable for:

1. soil types classified (AS 2870) as:

▪ Class A - sand and rock with no movement effects

from moisture changes

▪ Class S – slightly reactive clay

▪ Class M-D - moderately reactive clay

2. where the following conditions exist:

▪ the slope of the natural ground does not exceed 1 in

10

▪ the depth to rock is 1.2m or greater

▪ the ground-water table is permanently below 1.5m

from the natural ground surface or the final ground

surface, whichever is the lowest.

NOT recommended

▪ on sites classified as H-D, E-D and P, includes fill,

soil subject to erosion, soft soils (lack suitable load

bearing)

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Trench sizing & location

Development Act 1993 Minister's Specification SA 78AASeptember 2003On-Site Retention of Stormwater

See for size chart in SA 78AA to determine trench:- width- depth- lengthFor a range of connected roof/catchment areas


Sizing infiltration systems

Table 2 – Total length of trench (metres), ARI = 1 in 5 year, 1 hour stormMinister's Specification SA 78AA, September 2003, On-Site Retention of Stormwater

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Reduced impervious areas


Minimise impervious surface

areas by:

Source: www.staceroofing.co.uk

Source: www.hdsustainablelandscapes.com

Source: www.houzz.com Source: www.shedforce.com

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Permeable pavements

Source: www.marshalls.co.uk

Source: Baden MyersSource: Modi Building Technology


Infiltration v Detetion

Infiltration Detention

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Raingardens


Above ground design

A 100 mm to top of planter box

B 100 mm (min) to top of overflow pipe

C 400 mm (min) sandy loam

D 100 mm white washed sand

E 200mm (min) of 20 mm gravel + 50 mm of 7 mm screenings

New guideline - No gravel around plantsSource: Adapted from Melbourne Water

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How to size your raingarden

Area of run-off

(m²)

Area of

raingarden

(approx.) (m²)

50 1

100 2

150 3

200 4

250 5

300 6

350 7

400 8

450 9


Shopping List

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Shopping List

▪ Pond liner▪ 2 x 90mm x 1m PVC pipe▪ 50mm slotted agricultural pipe – to suit – minimum 3 metres

for 1m2▪ 2 x 90mm T junctions▪ 4 x 90x75x60x50x40 stormwater PVC stepped adaptor

(Holman)▪ 4 x 50mm couplings (Vinidex)▪ 2 x Elbow 90 degrees▪ 1 x 90mm PVC collar and cap and screen (with mesh to keep

mosquitos at bay) ▪ Plus pipework to connect to downpipe▪ Tape▪ 20 mm gravel (for area at 200mm depth)▪ 4 - 7 mm screenings or pebbles (for area at 50 mm depth)▪ Washed sand (for area at 100mm depth)▪ Sandy loam (for area at 400m depth)

Tools- Angle

grinder- Saw- Stanley knife- Pen- PVC glue- ruler


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How to construct a raingarden

Tips

1. Soil mix needs some clay (up to 3%) and organic matter (up to 5%)

to retain moisture between rainfall events

2. If your raingarden is greater than 4m wide install two slotted drainage

pipes (evenly spaced) and two overflow pipes


../WSUD in home_how to build raingarden/Raingarden_How to build domestic

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Plant selection

Stormwater pollutant removing plants:▪ Tall Sedge (Carex appressa)▪ Spiny-headed Mat-rush (Lomandra

longifolia)▪ Juncus aka Rush Grass (Juncus flavidus)▪ Mallee Honey-myrtle (Melaleuca ericifolia)▪ Hop Goodenia (Goodenia ovata).

▪ 50% of your raingarden should be planted with these species.

▪ other 50% can be made up of plants that like a dry environment with intermittent wet periods.


Planting regime

Note: Supplementary water may be required during the establishment period

▪ Planting density – 8 plants per m2▪ Denser planting is desirable to

reduce the opportunity for weed establishment

▪ Spreading herbs / mat forming species in lieu of mulch.

Mimulus repens

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Source: David Palmer


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Raingarden Species Selection

Figure 1 – Raingarden zones for plant selection

Planting zones


Plant species proven to be

effective at Nitrogen removal

Adapted from EPA Raingarden 500 guidelines

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Plant species proven to be

effective at Nitrogen removal



Plant species for companion

planting


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How to size your raingarden

Area of run-off

(m²)

Area of

raingarden

(approx.) (m²)

50 1

100 2

150 3

200 4

250 5

300 6

350 7

400 8

450 9

Vegetated Swales and buffer strips

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Swales

▪ Remove sediments▪ Promote infiltration▪ Delay runoff peak flow

Source: Melbourne Water

Source: www.ldsearthstewardship.org


Swale

Unless the swale is discharging to an existing stormwater surface pit, an inground

raingarden or infiltration raingarden, it will need to be fitted with an overflow pipe

connected back into the stormwater system.


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Material List – 2 m2 Swale

Approx. cost $200 - $300 (plus the cost of a plumber).



Maintenance

▪ Once established don’t need to be watered or fertilised.

▪ Some weeding needed until plants have matured.

▪ Evenly distribute water flow into the swale to limit erosion from heavy rainfall

- strategically placed rocks may help with

- flow spreader can be attached to the end of the downpipe.

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Thinking of building?


The 100m2 house

Dwelling footprint A – 100m2Allotment Size = 400m2Site coverage = 25%

Source: Levesque & Derrick Architects, lada.com.au

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5,000L rainwater tank for:▪ Toilet flushing▪ Laundry▪ garden




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The Crayon House

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The Crayon House

Source: Grieve Gillet Anderson Photo: S.Noonan

Rainwater (retention storage) = 42,000L, undergroundConnect roof area = 95%Internal re-use = all uses (HWS, laundry, toilets)Outdoor use = Yes, irrigation Self sufficient 9 months of year


The Crayon House


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The Crayon

House


Mellissa BradleyProgram Manager

[email protected] 828 980


Water sensitive urban design · Raingardens Above ground design A 100 mm to top of planter box B...

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