Managing the Development of a Multipurpose Corridor: Richmond Greenway
Borck Creek Catchment Mixed use corridor through the new development area. Designated in 2009: “The intention is to develop stormwater drainage infrastructure, recreation reserves and open space within the same land area to maximise the benefits of the compatibility of land uses, the cost and environmental efficiencies, and the long-term advantages to the community in providing for a reserve network built around open streams and drainage channels.” 1 1 : Borck Creek Notice of Requirement; MWH/TDC; Sept 2009
Corridor Development Objectives • Provide future-proofed conveyance of stormwater through Richmond South and West Development Areas • Provide for upgrades to Richmond Central Stormwater systems • Create recreational and amenity spaces where people can be connected to the waterways • Enhance the ecological value of the streams • Link areas of development by incorporating active transport routes
Richmond West Development Area Transforming a rural area into a new town.
Greenway Designation An opportunity to provide space for a waterway – but hard fought. • Borck Creek corridor 70m wide + 6m primary shared pathway. • Reduced from 120m as part of designation process. • 70m width required to convey Q100 flow (incl. CC & future development) • Some allowance in roughness budget for environmental & recreational enhancements • Poutama Stream 27m + 5m primary shared pathway • Increased from 15m to account for diversions of Richmond Central Stormwater • Depth controlled by Borck creek & Protected Oak trees. • Smaller roughness allowance than Borck to be able to contain flows
Borck Creek Current State
Design Challenges: • Landscape: • High groundwater • Flat grade • Balancing objectives: • Stormwater LoS • Ecology • Recreation • Transportation • Changing surrounding land use/zoning – HASHA Act • Changes in developer’s plans: • Stormwater discharge points • bridges • Surrounding ground levels • Constructability • Maintenance Considerations
Ecological Enhancement: • Guiding principles/objectives: • Mimic natural stream meander formation as much as possible • Provide diversity of habitat • Optimise shading of the channel • Provide for treatment of stormwater wherever possible • Constraints: • Cost • Channel capacity & hydraulic efficiency • Constructability • Maintenance considerations
Borck Creek Corridor Design Cross Section Active Channel Meander Zone A Shared path raised Low Flow Channel out of Q20 flood Recreation areas High enough above low flow to remain dry and mowable
Construction Challenges • Pace of development vs Council Budgets • Construction of parts of the channel are required ahead of budgets • Co-ordinating with developers • Utilising fill for developments – cost sharing • Completing bulk excavation while access is available • Lowering channels before stormwater drainage is required • Phasing of work stages • Flow from one physical section to another • Earthworks > Civils > Planting > Maintenance • On-site guidance requirements • Time & cost impacts • Risk of unintended impacts on performance of other outcomes
Poutama Stream February 2019 Poutama Stream March 2020
Recommend
More recommend
