Prioritising the mauri of our waterways
We investigated an urban creek catchment which flows through a highly modified urban area and drains a small portion of the wider Heathcote River catchment, Christchurch. The creek selected is a typical example of an urban catchment developed using a historical approach, which prioritised drainage over any other waterway values. Apart from some short enhanced and day-lit areas, 90% of the creek has been piped, modified into box drains or re-channelled. As well, the current configuration of residential and industrial land use creates cross-catchment travel issues and disjointed communities.
In it’s current state, the creek does not meet the Council’s six key waterway values, has poor water quality, has flooding issues in the downstream catchment and has low ecological and biodiversity value. Residents of the catchment have limited interaction with the waterway, which at present provides few social, cultural or environmental benefits.
WSP believed that short-term investments to improve the catchment, without considering of a long-term goal, would have little impact in improving the value of the creek to the surrounding area.
WSP used a future-focussed approach to provide a fit-for-purpose solution, appropriate for tomorrow’s world while aligning with today’s code. WSPs recommendations to Council integrated key future inputs of climate, society, technology and resources. The proposed solutions were developed by back-casting from the Council’s 100-year vision, and focused on fine-grained mixed-use development, inclusivity, integrating the catchment, and incorporating open and public spaces and nature.
WSP’s long-term vision transformed highly impervious areas to enhance natural infiltration of the catchment, and reduce urbanised peaks in runoff, which contribute to down-catchment flooding. The team identified three key developments in the catchment’s ‘Possible Future’, to ensure it was adaptive, resilient and regenerative.
1) Creek linear park
- Aesthetic open green space for people and ecology to thrive
- Establish biodiversity links and improved permeability to enhance infiltration for healthier levels of aquifer recharge
2) Light rail corridors
- Reinvigorate the existing transport network
- Improve connectivity and ease of access to parks and educational facilities
3) Residential and mixed use
- Facilitate a mixture of high-density population with ‘Smart’ urban design
- Community rainwater harvesting and green roofs to increase flood resilience
- Solar roofing and community gardens to reduce district level energy and food requirements
By reshaping the urban form of this typical Creek catchment, dead-zones between residential and industrial areas were minimised., and connectivity throughout the catchment established.
If implemented, the urban waterways creek vision will facilitate transformational change in how the catchment responds to the surrounding urban environment, as well as the challenges imposed by an uncertain future.
The additional green space will enhance biodiversity, recreation and amenity, while a range of native and exotic planting will benefit keystone pollinator species and surrounding ecology. The vision allows for double the catchment’s current population and through Water Sensitive Urban Design (WSUD), builds flood resilience but reducing imperviousness. Connectivity in the catchment will support access to education facilities, open spaces and public transport options.
- People-centred and inclusive
- Builds resilience to natural hazards
- District level energy and food production.
- Improved water quality and ecology / biodiversity
- Informed decisions for the district plan review (2019 – 2020)
- Created an implementation plan for public and private investments into the catchment to incrementally transform the area over the next 30 - 50 years.