Water Sensitive Urban Design guide

Wellington City Council has developed an introduction to water-sensitive urban design (WSUD) guide for stormwater management in Wellington.

A garden designed to filter water in lower Cuba Street.
A garden designed to filter water in lower Cuba Street

About water-sensitive urban design

Water-sensitive urban design (WSUD) is an approach to water resource management in urban environments that addresses both water quantity and water quality issues.

WSUD integrates natural water systems with built form and landscapes and promotes a more resourceful use of water.

Key elements include:

  • working with nature
  • avoiding or minimising impervious surfaces
  • utilising vegetation to assist in trapping sediment and pollutants.

Guide objectives

WSUD is an Our Living City initiative to:

  • promote natural drainage
  • help the piped networks to cope better with:
    • cross connections
    • under-capacity pipes
    • excessive rain
    • reduce incidents of sewer flooding to the sea.

Implementing WSUD concepts will:

  • reduce rainwater inundation of the piped system that causes flooding and overflows of sewage in the streams and the sea
  • help bring more native flora and fauna into urban areas
  • improve the attractiveness of the urban environment and the quality of life for Wellingtonians.

In Wellington the intention is to use storage and soakage to the ground to compliment the piped network, and not to replace the piped network.

Examples of WSUD incentives in Wellington

The Council has already implemented a number of WSUD solutions in the city which provide stormwater treatment and storage for run off from roads, pavements and other hard surfaces:

  • rain gardens along the quays
  • tree pits in lower Cuba Street
  • wetlands at Waitangi Park
  • Westchester Drive swales (shallow, sloping hollows designed to slow the flow of stormwater, trap pollutants and replicate nature).

The National War Memorial Park in Buckle Street will incorporate rain gardens to detain stormwater to irrigate the terraced park. 

Background to the guide

The WSUD guide has been produced in discussion with property developers, engineers, urban designers, landscape architects, parks and planners.  

Submissions received through formal consultation from the community, the Environmental Reference Group and other stakeholders on the draft WSUD guide resulted in a decision to change the presentation of the guide.

The most significant message from the submissions was that while the draft guide may encourage some to consider WSUD approaches, it lacked sufficient detail and clarity to facilitate implementation. Due to this feedback, we decided to split the guide into two separate but related documents.

The new guide:

  • introduces the concepts
  • outlines the benefits
  • gives the Wellington context.

In response to feedback from the Water-sensitive Urban Design Guide (WSUD) consultation we have moved the high-level technical information on WSUD devices into a separate but related document.

This more technical detail is currently being drafted to form a new chapter of the Council’s Code of Practice for Land Development, which outlines the minimum standard for design of roading, water, drainage and open space assets. The chapter giving technical information on WSUD devices will be used similarly when assessing land developments.