WSUD in your home & backyard Port Adelaide & Enfield Community Environment Group 19 October 2017 Mellissa 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 1
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 2
Reducing stormwater runoff benefits water cycle Source: Coutts et al. (2012) Urbanisation and changes to catchment hydrology 3
Water on a hectare of forest over a year Source: Centre for Water Sensitive Cities Water on a hectare of forest over a year Source: Centre for Water Sensitive Cities 4
Replace the forest with a building Source: Centre for Water Sensitive Cities Source: Centre for Water Sensitive Cities 5
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 6
Rainwater harvesting and re-use Rainwater tank collection system 1. ROOF SURFACE condition 7
Rainwater tank collection system 1. SURFACE condition 2. GUTTER MESH (6mm wire mesh) Rainwater tank collection system 1. ROOF SURFACE condition 2. GUTTER MESH (6mm wire mesh) 3. GUTTER OUTLETS 4. RAIN HEADS. 5. FIRST FLUSH WATER DIVERTERS. 6. TANK SCREEN 7. WATER TANK SIZE. 8. INSECT PROOF SCREENS or FLAP VALVES for TANK OVERFLOW OUTLETS. 9. TANK (MAINS) TOP UP 10. PUMP SYSTEM 11. FILTER Source: John Caley_Ecological Design 8
1. ROOF SURFACE condition 2. GUTTER MESH (6mm wire Rainwater tank collection systemmesh) 3. GUTTER OUTLETS 4. RAIN HEADS. 5. FIRST FLUSH WATER DIVERTERS. 6. TANK SCREEN 7. WATER TANK SIZE. 8. INSECT PROOF SCREENS or FLAP VALVES for TANK OVERFLOW OUTLETS. 9. TANK (MAINS) TOP UP 10. PUMP SYSTEM 11. FILTER Rainwater tank collection system 1. ROOF SURFACE condition 2. GUTTER MESH (6mm wire mesh) 3. GUTTER OUTLETS 4. RAIN HEADS. 5. FIRST FLUSH WATER DIVERTERS. 6. TANK SCREEN 7. WATER TANK SIZE. 8. INSECT PROOF SCREENS or FLAP VALVES for TANK OVERFLOW OUTLETS. 9. TANK (MAINS) TOP UP 10. PUMP SYSTEM 11. FILTER 9
Roof area to be connected to rainwater tank (m²) 14/11/2017 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 KENT TOWN (Average Annual Rainfall 583 mm) Rainwater Use Option Description Tank Capacity (L) High internal use 11L single flush toilet, 100% laundry (front load WM) & HWS Medium internal use 1 (6/3L) Dual flush toilet, AAA-rated shower head, 100% laundry (top load WM) & HWS Medium internal use 2 (6/3L) Dual flush toilet, AAA-rated shower head, 100% laundry (front load WM) & HWS Low grade uses (6/3L) Dual flush toilet and 100% laundry (front load WM) only 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 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% Assumptions: The internal water use estimates are based upon a 3 person household. 10
Supersize your rainwater tank 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 2,000L underdeck 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 Note: Prices are indicative only 3,000L modular 2,000L slimline Rainwater tank collection system 3. Gutter outlets 4. Rain heads. 5. First flush water diverters. 6. Tank screen 7. Water tank size. 8. Insect proof screens or flap valves for tank overflow outlets. 9. Tank (mains) top up 10. Pump system 11. Filter 11
Rainwater tank collection system Source: www.rainharvesting.com.au 1. Roof surface condition 2. Gutter mesh (6mm wire mesh) 3. Gutter outlets 4. Rain heads. 5. First flush water diverters. 6. Tank screen 7. Water tank size. 8. Insect proof screens or flap valves for tank overflow outlets. 9. Tank (mains) top up 10. Pump system 11. Filter Typical cost: Plumbing (labour) $450-$800 Pump system $500-$800 Filter $400-1,000 Maintenance of water quality Clean gutters and screens Vacuum sediments from bottom of tank Replace filter cartridges 12
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 13
Tap aerators reductionrevolution.com.au Cold water diverters redwater.net.au 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 14
Onsite retention of Stormwater via infiltration Infiltration trenches 15
Restoring the balance in the urban water cycle In-site retention infiltration systems Suitable 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) 16
Trench sizing & location Development Act 1993 Minister's Specification SA 78AA September 2003 On-Site Retention of Stormwater See for size chart in SA 78AA to determine trench: - width - depth - length For a range of connected roof/catchment areas Sizing infiltration systems Table 2 Total length of trench (metres), ARI = 1 in 5 year, 1 hour storm Minister's Specification SA 78AA, September 2003, On-Site Retention of Stormwater 17
Reduced impervious areas Minimise impervious surface areas by: Source: www.hdsustainablelandscapes.com Source: www.staceroofing.co.uk Source: www.houzz.com Source: www.shedforce.com 18
Permeable pavements Source: www.marshalls.co.uk Source: Modi Building Technology Source: Baden Myers Infiltration v Detetion Infiltration Detention 19
Raingardens Above ground design A B C D E 100 mm to top of planter box 100 mm (min) to top of overflow pipe 400 mm (min) sandy loam 100 mm white washed sand 200mm (min) of 20 mm gravel + 50 mm of 7 mm screenings New guideline - No gravel around plants Source: Adapted from Melbourne Water 20
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 21
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 22
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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 27
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 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. Note: Supplementary water may be required during the establishment period Mimulus repens 28
Source: David Palmer 29
Raingarden Species Selection Planting zones Figure 1 Raingarden zones for plant selection Plant species proven to be effective at Nitrogen removal Adapted from EPA Raingarden 500 guidelines 30
Plant species proven to be effective at Nitrogen removal Adapted from EPA Raingarden 500 guidelines Plant species for companion planting Adapted from EPA Raingarden 500 guidelines 31
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 32
Swales Source: www.ldsearthstewardship.org Remove sediments Promote infiltration Delay runoff peak flow Source: Melbourne Water 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. Source: Melbourne Water 33
Material List 2 m 2 Swale Approx. cost $200 - $300 (plus the cost of a plumber). Source: Melbourne Water 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. 34
Thinking of building? The 100m2 house Dwelling footprint A 100m2 Allotment Size = 400m2 Site coverage = 25% Source: Levesque & Derrick Architects, lada.com.au 35
5,000L rainwater tank for: Toilet flushing Laundry garden Source: Levesque & Derrick Architects, lada.com.au Source: Levesque & Derrick Architects, lada.com.au 36
Source: Levesque & Derrick Architects, lada.com.au The Crayon House 37
The Crayon House Rainwater (retention storage) = 42,000L, underground Connect roof area = 95% Internal re-use = all uses (HWS, laundry, toilets) Outdoor use = Yes, irrigation Self sufficient 9 months of year Source: Grieve Gillet Anderson Photo: S.Noonan The Crayon House Source: Grieve Gillet Anderson Photo: S.Noonan 38
The Crayon House Source: Grieve Gillet Anderson Photo: S.Noonan Mellissa Bradley Program Manager mellissa@watersensitivesa.com 0431 828 980 39