Decision process for stormwater management
The Decision Process for Stormwater Management in WA provides an approach and outcome criteria for planning and designing stormwater management systems for urban (greenfield, infill and brownfield) developments and when planning and designing existing stormwater management system retrofits.
This is the third edition, with the first edition originally published in 2005 and subsequently updated in 2009.
The decision process is a component of the Stormwater Management Manual for Western Australia.
The desired outcomes of the decision process is for urban stormwater management systems to be planned and designed to:
- protect public health and safety
- protect public and private infrastructure and buildings from flooding
- protect and enhance sensitive receiving environments by managing the water cycle, water quality, habitat diversity and biodiversity
- enable economically sustainable construction, maintenance and renewal/replacement costs
- achieve good urban amenity.
These outcomes can be achieved by:
- designing urban stormwater management systems that reduce risk to people and property from flooding to within acceptable levels
- designing urban stormwater management systems that mimic natural hydrological processes for that catchment
- retaining natural water bodies as the receiving environments for runoff of suitable quality from minor and major rainfall events
- retaining and planting vegetation (preferably local native species) wherever possible to reduce stormwater runoff volumes and peak flow rates, reduce urban temperatures, improve water quality, increase urban biodiversity, and improve aesthetics and urban amenity
- implementing stormwater management systems and site management, maintenance and other practices to prevent, reduce and treat pollutants
- designing urban stormwater management systems that achieve good urban amenity and provide multiple functions.