Background

Urban Nutrient Decision Outcomes (UNDO) is a simple conceptual decision support tool with a flexible framework that evaluates nutrient reduction decisions for urban developments on the Swan Coastal Plain in south-west Western Australia. It is specifically designed for ease-of-use by urban development proponents and for assessment by local and state government authorities. This document provides the user with a step-by-step guide to accessing the model, implementing an urban development, using the various decision options in the tool to reduce nutrients exported from the urban development, and printing and submitting a report to the relevant decision making authority.

📄️ The requirement for a nutrient model

Stormwater runoff is a significant contributor to nutrient export into estuaries, wetlands and lakes on the Swan Coastal Plain. These water bodies are not naturally adapted to high-nutrient conditions and are prone to excessive algal growth as a result of increased nutrient runoff. In many cases, this has resulted in toxic algal blooms, fish deaths, deoxygenation and release of noxious gases and odours, and water bodies unsuitable for boating and recreation. There are major environmental issues (fish deaths, eutrophication, toxic algae), social issues (unsightly water bodies, water bodies not fit for swimming, boating or fishing) and economic issues (millions of dollars per year spent by state and local governments treating these symptoms) associated with elevated nutrients in our receiving water bodies.

📄️ UNDO Tool philosophy

The urban development industry and state and local governments have recognised the need for the tool to have the following capabilities:

📄️ What the UNDO tool will not do

It is important for users to understand the limitations of any model. Below is a list of exclusions. The UNDO tool: