20517 App J.pdf [As Published] · 132007.1259

Concept Stormwater Management Plan
Essence of Peregian

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5.0 WATER BALANCE MODELLING

Noosa Council's Planning Scheme Policy requires for the development to demonstrate no increase in average
annual runoff volumes from the site. In order to demonstrate this, a water balance simulation was undertaken for
the:

e Existing scenario
e Developed scenario, and
e Developed scenario with rainwater reuse measures applied.

The aim is to show that the developed scenario annual runoff volume (with no reuse measures applied), less the
total volume of rainwater used by proposed reuse measures, is less than the runoff under the existing scenario.

Demands of tank water in the analysis were:

e Irrigation of landscaping around accommodation buildings, and
e Toilet flushing and laundry facilities in beach shacks.
5.1 Demand Reduction

The targets for water demand reduction was adopted from the MSC Integrated Water Management Guidelines
(2006). The Planning Scheme Policy target represents an equivalent population consumption of
240 Liperson/day. This demand value was applied to the beach shacks where internal reuse is proposed.

5.2 Proposed Measures

The following strategies will be employed to reduce potable water demand from the development:

e Efficient Water Use - to maintain a constant supply of water from a limited source, efficient water usage
and design principles will be incorporated throughout the development. This will include at minimum
AAA rated water saving devices (such as dual flush toilets, low-flow showers and faucets, front loading
washing machines and efficient dishwashers) and pressure management. Landscaping incorporating
water efficient vegetation will also be incorporated throughout the development.

« Rainwater Capture and Reuse — Two rainwater tanks of 3 kL total capacity are proposed for éach beach
shack and will supply water for toilets and laundry.

e Irrigation using Rainwater - Three underground rainwater tanks are proposed for the accommodation ,
buildings on the site. Rainwater will be sourced from roof runoff only. There will be a tank for each of
the following pairs of accommodation buildings:

> Buildings A1 and B1 (southern end of site)
> Buildings A2 and B2 (central end of site)
> Buildings C1 and B3 (northern end of site)

5.3 Water Balance Analysis

5.3.1 Rainfall Data

Rainfall data necessary to undertake the rainwater tank analysis was taken from the Rainman Professional
Edition Version 4.3, published by the QLD Government Department of Primary Industries (June 2003). Rainfall
data was analysed from the Tewantin Post Office Rain Station 10 km north of the site. This station was deemed
to be the most appropriate as it was the closest station to the development site and approximately the same
distance (3.25 km) inland.

 

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