From Vision to Reality: Stormwater Tree Pits in Central Christchurch

Stormwater Conference

Christchurch residents have articulated a vision for their future central city to be greener and more liveable. Guidance documents released by Government agencies promote integrating stormwater treatment into the design of the public realm and this includes stormwater tree pits in the central city. Significant challenges need to be overcome before this vision can become reality however, such as construction around existing services, connecting to a shallow stormwater pipe network, maintaining overland flow paths, allowing for future maintenance and meeting tight budgetary constraints.

Christchurch City Council recently developed stormwater tree pit design guidelines to facilitate their use in Christchurch. Specimen designs were also undertaken to test the feasibility of implementing stormwater tree pits in central Christchurch. ‘An Accessible City’, Christchurch’s central city transport framework, provides the first test for the implementation of these guidelines.

This paper presents a summary of the process of taking the vision of stormwater tree pits in central Christchurch to the detailed design phase for the Accessible City project.

Manchester Street and the Durham/Cambridge transport corridors provide a case study to show how the design challenges were overcome. A range of variations in stormwater tree pit configurations were necessary to allow for as much flexibility as possible. Stormwater tree pits were located both in on-street parking bays and behind the kerb in the footpath. In some places they were combined with rain gardens to increase the treatment area. An innovative tree pit design from Stockholm was implemented where there were clusters of trees. In other places only passive irrigation of tree pits could be achieved. The work demonstrates that where a flexible and innovative approach is adopted then stormwater tree pits are suitable for retrofit into existing urban centres.

Conference Papers Resource - Conference Papers Stormwater

2. Peter Christensen.pdf

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22 Jun 2016