Integrated Water Management on Development Sites

Pursuant to Amendment VC154 Stormwater Management and an update to the Environment Protection Authority (EPA) Victoria’s State Environment Protection Policy (Waters) in October 2018, Council requires a comprehensive assessment to address performance against Integrated Water Management (IWM) principles.

Principle	Considerations
Volume Reduction	Address run-off at pre-development levels whereby post development is no more than pre-development annual average runoff volume (as per the Urban Stormwater Best Practice Environmental Management Guidelines (BPEMG) 1999 regarding flow, maintain discharges for the 1.5 year ARI at pre-development levels).
Peak Flow Discharge	On-site detention via detention tanks, pits or pipes where required to Council’s satisfaction; Permissible Site Discharge (L/min) (PSD) values; and Location of Legal Point of Discharge (LPD).
Stormwater Quality	Pollution control through Water Sensitive Urban Design Measures (WSUD) including a combination of: Rainwater tanks for retention/re-use purposes; Permeable or porous paving; and Raingardens or swales (considering also relative levels (RLs) stated on Development Plans) Informed adherence to the Urban Stormwater Best Practice Environmental Management Guidelines (BPEMG) 1999 regarding pollutants) [noting that Melbourne Water’s STORM tool presents a limited depiction of a complete 100% STORM score outcome].
Rainwater Tank Overflow	Calculation of rainwater tank overflow that is either reduced through increased demand or treated through a secondary system prior to release to LPD in order to avoid undermining stormwater quality performance.
Rainwater Tank Reliability/Supply	End use demand met by the rainwater tank considering: Rainwater tank size; Roof catchment area (noting that if the entire roof area is connected to a rainwater tank, a charged piping system must be proposed and will be conditioned by Council); and Connection to toilet flushing, laundry, irrigation, bin wash down or hot water systems where appropriate.
Potable Water Demand Reduction	Rainwater tank size; Water efficient fixtures and fittings (i.e. Water Efficient Labelling and Standards (WELS)), particularly for: Toilet flushing systems; Taps; and Showerheads

Dual Occupancy and Townhouse Developments

For dual occupancy and townhouse developments (2 or more dwellings or residencies on a lot) Council is not generally favourable of raingardens. In lieu of raingardens, a general expectation to assist towards addressing Council’s collective requirements includes:

Sizing rainwater tanks to a minimum 3,000 litre capacity per dwelling for re-use/retention purposes only;
Connecting rainwater tanks to all toilet flushing and laundry systems, as well as, irrigation areas;
Unless otherwise stated to provide a charged piping solution or equivalent, Council will consider that 60% of the roof area is connected to rainwater tanks; and
Permeable or porous paving to driveway areas to address relevant performance shortfalls.

Required Plans

Council requires that all IWM requirements are consistently and transparently provided on the following plans:

Development;
Drainage; and
Landscape.

Where applicable, location of systems/features and annotations must be demonstrated on plans to include, where relevant:

The rainwater tank location, size and accessibility to ensure maintenance and servicing;
That the rainwater tank is independent of detention requirements and shall only be used for retention/re-use purposes;
Connection of rainwater tanks to relevant systems and areas (i.e. connected to all toilets and laundry systems, as well as, irrigation areas);
The use of a charged pipe system;
Areas constituting permeable and porous paving as opposed to concrete;
Location of raingardens and relevant cross sections;
Inclusion of relative levels; and
Location of detention tanks, pits and pipes including LPD.

Management and Appropriate Execution of Requirements

It is advised that the applicant work collectively with a town planner, environmentally sustainable development (ESD) consultant, and drainage engineer to provide a complete, accurate and transparent solution to ensure an efficient outcome throughout the town planning and engineering process.

To assist Council, the following documentation may be considered:

Drainage engineering computations;
A STORM, MUSIC, Tankulator and/or InSite Water assessment or equivalent;
Water efficiency commitments for fixtures and fittings; and
Plans (as above).

The proposed solution shall be reviewed by several Council departments including town planning, environmentally sustainable development, drainage and stormwater.

Council’s comments may constitute amending the proposed solution to best reflect Council’s IWM requirements and expectations. Relevant requirements may be stated as planning permit conditions or otherwise to the satisfaction of the Responsible Authority.

Please note: Addressing Council’s IWM requirements shall assist with supporting Council’s ESD Policy (Clause 22.10-2 Objectives) and Apartment Design Guidelines for Victoria 2017 [BADS] (Standards D13 and B39) requirements accordingly.

Planning Victoria DELWP also provide further information regarding VC154 Stormwater Management.

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Integrated Water Management on Development Sites