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Innovative and adaptive design approaches to support integrated water management Deakin Waurn Ponds Campus Stormwater Victoria Conference 2022 Caroline Chandler and Aaron Dowling, E2Designlab Ella Cole, Deakin University
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Creating a water sensitive Waurn Ponds campus Adaptive approaches to the design and delivery of IWM at Deakin University Waurn Ponds Campus Alleviate flooding impacts, increase amenity and secure water supply for the future Image: Waurn Ponds Landscape Master Plan, REALMstudios
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Where is Waurn Ponds campus? We are here!
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Key challenges Low lying location Rapid growth Stormwater network exceeds capacity Localised flooding Water quality issues Impact on the greater waterway network High irrigation needs
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Strategic Context: Regional Priorities
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Applying the Barwon IWM Strategic Outcomes
2020 Deakin University IWM Plan Waurn Ponds Campus
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A tailored response to regional strategic outcomes Feasibility assessment to connect to Class A Recycled Water Improve water efficiency data Upgrade potable water network and pressure 2020 Deakin University IWM Plan Waurn Ponds Campus
Upgrade sewerage system capacity and improve sewerage operational effectiveness Review and implement proposed Flood Mitigation measures Develop and implement a Stormwater and Drainage Plan Improve stormwater and drainage Develop a Landscape Master Plan
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From design to delivery Deakin University IWM Plan
2020
Phase 1: Waurn Ponds IWM Concept Plan
2020/21
Phase 2: Stormwater and Recycled Water Asset Design
2021/22
Phase 3: Construction
2022
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PHASE 1: DEVELOPING AN INTEGRATED MULTI BENEFIT IWM ONSITE CONCEPT
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Phase 1: Waurn Ponds IWM Plan
Stormwater Management Plan
Class A Recycled Water
Flood mitigation investigations
Sewerage Systems Review
Landscape Master Plan
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Deakin University Waurn Ponds Campus Overview:
Originally built in 1977 in the valley of a tributary to Waurn Ponds Creek
Students, university staff, businesses and locals regularly use campus site
Campus is expanding: advanced manufacturing facility, industrial type buildings
Central drainage line
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a series of five deep online ponds along tributary
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Highly degraded and actively eroding waterway in upper catchment
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Pipe connection through centre of campus
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Constructed waterway and feature campus entrance pond
Key water demands include: –
Irrigation: football field, athletics track
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Student residences: household
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Education facilities: existing and new
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Convert existing ponds to wetlands Opportunity to convert top three existing ponds to wetlands to provide broader benefits: – – – – –
Stormwater quality Flood detention Biodiversity Amenity value Safety
Important to maintain/enhance flood storage above within the floodplain for flood mitigation purposes Can be integrated with landscape design Fifth pond is central to campus, high aesthetic value. Retain its current state, enhance planting and edge treatment.
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Entrance Pond Retrofit
Reconfigured to provide:
Stormwater harvesting
Water quality treatment
Flood storage
Enhanced biodiversity
Visual amenity (open water)
Challenges
Inundation frequency
Isolated storage (sunk tank)
Flow velocity – biofilm scour and sediment resuspension
Existing values:
Retain open water for visual amenity
Flora and fauna protection and enhancement
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Class A Recycled Water Supply Feasibility New irrigation tank and pump shed
Potential ring main expansion
Proposed new ring main
Connection from Armstong Creek Class A recycled water network
New DN150 ring main to reticulate throughout campus. Can be expanded to accommodate future campus growth
Quality carefully considered. Supply must be fit-for-purpose
Potable backup can be supplemented with stormwater harvesting from entrance pond
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Flood Mitigation Existing Conditions 1% AEP Flooding Recommended interventions:
4
1 2 3
1.
Interception bund prevents overtopping of escarpment and diverts overland flows away from buildings
2.
Pipe upgrade increases underground drainage capacity, daylights into a wet swale overland flow path.
3.
Pipe and pit upgrades increase underground capacity.
4.
Interception bund prevents overtopping of escarpment and diverts overland flows away from football field
Future flood risk: Additional storage and regulated outlets achieved though pond wetland conversions
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Landscape Masterplan Identified a total of 17 landscape interventions Conversion of linear network of ponds to online wetlands with flood storage Stormwater harvesting storage and wetland Waterway stabilisation and rehabilitation Class A Recycled Water interface with stormwater Integrated flooding and overland flow management
Image RealmStudios
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Option Prioritisation – BCA Chain of ponds conversion
Recycled water ring main
Entrance pond conversion
Intervention Reference: 1. 2. 3.
Pipe upgrade & open swale Western waterway
4. 5. 6. 7. 8. 9. 10.
Bund
11. 12. 13. 14. 15. 16. 17.
Retrofitted chain of ponds with wetlands for water purification and flood storage capacity (Ponds 1, 2, 3 & 4) Retrofitted Library Pond (Pond 5) Retrofitted Entrance Pond (Pond 6) and irrigation water tank as feature landmark element Retrofitted S-Pond (Pond 7) Pipe upgrade and new open swale Bund construction, integrated into coir log landscape (12) Western Waterway Drainage infrastructure upgrade Union Square pipe upgrade Union Square landscape upgrade: canopy trees and vegetated soaks Advanced treatment plant, recycled water storage tank, pumphouse and irrigation ring main Retrofitted open channel to daylight minor flow events Coir log landscape for local water infiltration Conservation zone and regenerated ecological corridor along Waurn Ponds Creek Overland green corridor Road network with integrated WSUD elements for water conveyance New car parks in campus extension zone with integrated WSUD elements for local infiltration
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PHASE 2: ADVANCING AND ADAPTING STORMWATER ASSET DESIGN
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Phase 2: Advancing Stormwater Asset Design
Functional Design
Class A Recycled Water Detailed Design
Flood modelling
Landscaping
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Stormwater asset design overview Entrance Pond
Chain of Ponds
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Civil and Landscape Design - Adaptive Decision Making Wetland design and landscaping Safety in design – safety edges for open water Opportunity to reuse materials on site Consideration of trenchless construction methodologies Placement of sediment drying basins Removal and retention of trees
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Entrance Pond Design
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Design responses
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Final Design
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PHASE 3: CONSTRUCTION
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Adaptive responses to delivery Staged dewatering of ponds and program flexibility Fauna management and relocation considerations Constraints of working in a live environment
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Site Establishment & Staging of Works STAGE 1 • Earth Bund • Drainage Channel • Ponds 1, 2 and 3 STAGE 2 • Ponds 4 and 5 STAGE 3 • Pond 6 – Entrance Pond
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Fauna Management & Dewatering Dusky Moorhen Gallinula Tenebrosa
Eastern Long-necked Turtle
Native Species • 7 aquatic species including: • Eastern Long-necked turtles • Common Yabby • Golden Perch • 24 bird species including 14 water bird species • 3 amphibian species including: • Eastern Common Froglet • Southern Brown Tree Frog • Spotted Marsh Frog Pest Species • 2 aquatic species • European Carp • Goldfish • 2 mammals • European Rabbit • European Hare
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Stage 1 - Progress to Date
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Stage 1
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Additional outcomes Research Opportunities • The IWM project has presented the opportunity for the Ponds to be used as Living Laboratories. • A Deakin PhD student has been undertaking sampling of the water and sediment, prior to commencement of the works, throughout construction, and will continue upon completion of the project. Removal of Pest Species • Ponds 4 and 5 were not originally planned to be fully de-watered, however the project has presented an opportunity to fully dewater them so the pond dries out enough for the Carp eggs die off.
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Learnings Clearly defined outcomes enable an adaptive response to asset design and delivery Strong and regular engagement between consultant team, contractors and client Responsive and adaptive decision making by the client
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THANK YOU