Where UNDO tool fits into the planning process

Integrated water planning with land use planning processes for Western Australia is defined in the Western Australian Planning Commissions document Better urban water management (WAPC 2008). A flow chart describing each stage of the planning process is shown in Figure 2-1.

Figure 2-1: Nutrient planning process within the Better urban water management (WAPC 2008) framework

Planning and design for appropriate discharge of nutrients from urban developments is primarily done in two stages of the planning process: the district and local stages. This is associated with two water documents: water management strategies at the district and local levels. According to Better urban water management, a district water management strategy should:

‘Define catchment objectives and design objectives for water quality, quantity and conservation for local planning and subdivision’

At this stage, proponents should explore the nutrient constraints of the development area. This includes finding out if there are existing nutrient export targets or water quality guidelines for the area or its surrounding catchment. The UNDO tool is not generally used at this stage, as many of the design and data requirements for the tool (e.g. lot sizes, landscaping, detailed drainage design) are not yet available. However, by assessing nutrient export guidelines or targets at this stage, developers are provided with a general picture of how constrained the site is by nutrient issues. This provides users with some preliminary planning decisions for when the UNDO tool is applied (for example, if the area is heavily constrained by nutrient issues, the developer will know from the outset that a nutrient-sensitive design is required).

The UNDO tool will generally be used in the local planning stage of the development. According to Better urban water management, a local water management strategy contains the following:

• results of detailed monitoring and modelling of surface water and groundwater quality and quantity
• identification of water management infrastructure and strategies required to meet design objectives.

This is the appropriate level of planning for applying the UNDO tool. The tool’s report, generated once the development design is finalised, will generally be submitted as an appendix to a local water management strategy. Local government may also want proponents to use the UNDO tool at the Urban Water Management Plan stage of development.

The UNDO tool may also be used to assess the reduction in nutrients that would result from catchment retrofitting. In these instances, the application of the UNDO tool generally will not be associated with a local water management strategy (depending on the type and scale of redevelopment), and the framework for its use will be project specific.