Improving Catchment Health While Reducing Flooding: the Opāwaho/Heathcote River Story

Stormwater Conference

The Ōpāwaho / Heathcote River catchment has a history of flooding and poor water quality. The impact of flooding was increased due to land settlement and channel damage as a result of the Canterbury Earthquake Sequence (CES) from 2010 onwards. The response to the effects of the CES through Christchurch City Council’s (CCC) Land Drainage Recovery Programme (LDRP) was primarily to restore flooding to pre-earthquake levels. However, the flood mitigation infrastructure has also provided a significant opportunity to improve water quality and provide for some of the community aspirations for the Ōpāwaho / Heathcote River corridor. This demonstrates good practice in considering multiple values within floodplain management, and ensures the greatest return for the community from an investment of over $100 million in infrastructure.

CCC has a multi-value approach to stormwater management, aiming to deliver on the following six values: drainage, culture, ecology, heritage, recreation, landscape. Leading edge when introduced, this approach has been embedded into stormwater infrastructure delivery in Christchurch. This has ensured that the infrastructure delivered as part of the Ōpāwaho / Heathcote River floodplain management scheme has far wider benefits than just flood reduction.

Some of the ‘non-drainage’ results achieved by CCC adopting a multi value approach and obtaining input from a wide range of groups include:

  • Wetland treatment of stormwater on two of Christchurch’s most polluted streams (the Curletts and Haytons Stream tributaries)
  • Sediment capture on the two most significant sediment sources for the Ōpāwaho / Heathcote River (Cashmere-Worsley and Hoon Hay valleys)
  • Removal of contaminated sediments through dredging
  • Planting of several kilometres of banks with primarily native vegetation
  • Restoration of significant areas of wetland habitat drained for farming
  • An urban forest (Te Oranga Waikura) co-located with a stormwater basin
  • Filtration of a large (160 hectare) commercial/residential catchment with the largest proprietary treatment device in New Zealand
  • Recreation areas, such as an area of tracks and open space of approximately 100 hectares
  • Isolation of important bird habitat areas from predation
  • Telling the cultural and heritage narrative
  • Enhancement and extension of inanga spawning habitat
  • Adoption of areas by local school groups to maintain and extend planting
  • Combined together, these represent a significant improvement in the health of the Ōpāwaho / Heathcote River catchment and provide a platform for ongoing improvement in catchment health. Community involvement in achieving these outcomes has been important, with stream care and river network groups engaged during the design and implementation phases.

    This paper will provide examples of the multiple values achieved, describe the process undertaken to achieve this, and discuss the lessons learnt throughout the process.


    2 MB
    30 Sep 2019


    76 MB
    30 Sep 2019