Water Sensitive Urban Design (WSUD)
Water Sensitive Urban Design (WSUD)
What is WSUD?
WSUD is a planning and water management philosophy that attempts to achieve:
“the integrated design of the urban water cycle, incorporating water supply, wastewater, stormwater and groundwater management, urban design and environmental protection. It represents a fundamental shift in the way water and related environmental resources and water infrastructure are considered in the planning and design of cities and towns, at all scales and densities.”
(Joint Steering Committee for Water Sensitive Cities, July 2009).
Council’s Commitment to WSUD
In 2011, Council adopted a WSUD Policy for Council Infrastructure Assets that seeks to integrate sustainable water management principles into Council asset management practices. The policy commits Council to a number of WSUD goals including:
- Reduction of potable water use
- Maximising water re-use
- Reduction of wastewater discharge
- Minimisation of stormwater pollution before discharge to receiving waters and
- Protection of groundwater.
The policy also commits Council to a 40% reduction of potable water consumption below the baseline year of 2000/2001 by 2015. Council’s operations are already tracking well ahead of schedule to meet that target with the 2010/11 financial year revealing that water savings were now running at 59% below the 334 million litres used in 2000/2001.
In addition, in 2009 Council adopted stormwater quality improvement targets to achieve 10% of the best practice performance objectives by 2020 for Council managed assets as outlined in the Urban Stormwater Best Practice Environmental Management Guidelines (Victorian Stormwater Committee, 1999).
The policy also provided impetus to the development of WSUD Guidelines for City of Yarra Works which can be viewed below:
WSUD Guidelines for Infrastructure Services Works in Yarra - Updated October 2012 (2.48 MB)
Stormwater Management - Quality and Quantity
Stormwater is a term used to describe all the rainwater runoff that reaches the ground in urban areas and mixes with surface contaminants (eg. fertilisers, herbicides, pesticides, fallen leaves, grass clippings), road and paved area pollutants (including fuel, oil, particles from brake linings, sediment that drops from the underside of vehicles) and other materials (eg. litter, animal faeces). Find out more about stormwater drains.
Most of the rain that falls in urban areas comes off roofs and paved areas and is discharged to local streets where it can enter underground drains often owned by Council. In the City of Yarra about half the municipality has underground drains below its streets – the other half are dependent on the capacity of the kerb and channel to take stormwater along streets until it connects with an underground drain – either Council’s or the Melbourne Water regional drainage system. From there, the stormwater travels by gravity to waterways (eg. Merri or Darebin Creeks or Yarra River in the case of City of Yarra).
Improving the quality of stormwater is important for the health of our waterways, bays and oceans. Managing stormwater to keep it free of litter and pollutants protects the wide range of plants and animals in our waterways and ocean environments. This is also important from a human perspective - clean creeks, rivers and beaches benefit everyone. Litter and toxic bacteria or chemicals pose risks to human health, and their presence in waterways and the sea restricts our ability to enjoy and use those areas. Reducing the load of litter and pollutants in stormwater is a difficult task, because there is not one specific source of pollution. Litter and pollutants come from everywhere, and keeping them out of stormwater requires broad, community-wide understanding and behaviour change. About 2 billion litter items are washed into the stormwater system in Melbourne every year (Melbourne Water, July 2001). Litter harms native wildlife such as platypus, is unattractive to look at and expensive to clean up.
Because stormwater pollution is something we all contribute to it - either directly or indirectly - here are some simple steps which will help reduce and prevent it:
- Where possible wash your car on the lawn or at a commercial car wash facility. Do not wash it in your driveway or on the street - the detergent will go straight into the stormwater drain. Washing on the lawn achieves two things at once - your car gets cleaned, and the lawn gets watered too! Many commercial car washes recycle and re-use their water, which reduces water consumption as well as protecting stormwater
- Put litter in the right place, and make sure it is secure and won't be blown around. Don't just pick up the paper and plastic - get the leaves, grass clippings, and animal faeces as well
- When working with chemicals and other substances (eg. changing your car oil, or spraying in the garden), make sure nothing can get washed into the gutter. Dispose of unwanted chemicals correctly, at facilities which are equipped for that purpose
- When working on house or garden projects, minimise the amount of soil left exposed or protect it from wind and rain with a tarpaulin. Keep stockpiles of topsoil or sand away from gutters, and cover them with a tarpaulin to prevent sediment runoff
- Tell others about how their activities impact on stormwater and the wider environment. Help them to understand how they can protect stormwater too
- Refer to Yarra's Builder's Code of Practice for information on how to prevent stormwater contamination on building sites.
The stormwater system also needs to cope with large quantities of water to avoid undue flooding of streets, transport corridors, and businesses and property during high rainfall events. Some flooding will inevitably occur in extreme rainfall events due to flows exceeding the capacity of underground drains and street kerb and channel, blockages of drain entry pits (often from litter and debris) and low points in the landscape inevitably attracting the ponding of water where the quantity exceeds the capacity of the local discharge point. The number of locations within the City of Yarra where flooding is deemed to be an issue, is relatively small.
Stormwater quantity is now considered to be a significant constraint on the health of local waterways.
Given the extent of impervious surfaces in urban areas, and the efficiency of underground drains, streams now receive much greater volumes of water than in pre-European times. These excessive volumes of stormwater – quite apart from the pollutants they carry - scour stream banks, increase channel width (sometimes causing loss of adjacent private property), disturb vegetation growing along the banks and increase stream turbidity effecting light penetration and smothering plants and animals on the stream bed. A reduction on stormwater quantity is therefore just as desirable as improvements to stormwater quality.
In order to address quantity issues, it is desirable that stormwater is retained within catchments. Rainwater tanks and other measures to capture and re-use stormwater are therefore highly desirable. The City of Yarra and other inner Melbourne Councils are currently examining options to ensure that new developments address stormwater retention as well as quality management.
Council’s WSUD Plans and Guidelines
In 2006 Council developed a Water Action Plan which set out a host of actions for Council to implement across its various facilities and other assets (eg. open space, buildings, depots etc.). The Plan also recommended actions to improve stormwater quality.
City of Yarra Water Action Plan (810.75kB)
In 2007, Council prepared Water Sensitive Urban Design Guidelines which attempted to provide direction on how to achieve the sustainable water objectives as outlined in the 2006 Plan. The Guidelines were divided into 3 sections as set out below. The first section dealt with Guiding Principles and provided guidance to:
- Find ways to reduce water consumption
- Replace potable water with another water source
- Manage stormwater before discharge
- Undertake design and address approvals needed for WSUD
- Assist operations and maintenance
Water Sensitive Urban Design - Guiding Principles (3.16MB)
The other sections of the Guidelines outlined various case studies and applicable fact sheets.
City of Yarra case studies - Single Allotment (371.84kB)
Water Sensitive Urban Design - Factsheets (3.28MB)
Implementing water-sensitive urban design
Council has begun implementing various WSUD projects over recent years. In June 2010, 18 trees irrigated with stormwater were planted on the western side of Smith Street in Fitzroy, between Johnston Street and Alexandra Parade. More than 50 on-street raingardens have also been constructed throughout Yarra since the firts raingardens were established in Cremorne Street in 2002/3 (see below).
In October 2011, Council officially opened the raingarden at Edinburgh Gardens in Fitzroy North. Built with the support of Melbourne Water, the raingarden will store enough water to irrigate 50% of the park's trees and is Council's largest Water Sensitive Urban Design project to date. Click here to find out more. Wetlands in Clifton Hill have also been built below Walker Street adjacent to Merri Creek to treat stormwater coming from a small catchment in the vicinity of Walker Street.
Above Cremorne Street Raingardens, below Stanley St., Collingwood
Asset Drainage Engineer
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