Perth
41.3 Runoff into storages

Supporting Information

Total volume of runoff into each urban supply storage during the 2010–11 year within the Perth region is provided in the following table.

 

Total volume of runoff into each urban supply storage during the 2010–11 year

Storage

Runoff (ML)

Canning

3,604

Churchman Brook

561

Mundaring

72

North Dandalup

947

Samson Brook

650

Serpentine

1,527

Serpentine Pipehead

South Dandalup

3,988

Stirling

6,215

Victoria

166

Wungong

1,530

Total

19,260

 

Quantification Approach

Data Source

Bureau of Meteorology, National Climate Centre: daily climate grids (rainfall, temperature and solar radiation), Bureau of Meteorology: Australian Hydrological Geospatial Fabric – waterbody feature class, Australian Water Resources Information System – water storages, Water Corporation: Operational Data Storage System database.

Provided by

Water Corporation and Bureau of Meteorology.

Method

Runoff into surface water storages used for urban water supply was calculated based on a water balance calculation using measured data collected at each storage. The runoff into each storage is calculated using the following water balance equation:


Runoff =  ΔS + O + E - P - T

 

where:

ΔS is the change in storage

O is total outflow from the storage

E is evaporation from the storage (line item 42.1)

P is precipitation on the storage (line item 41.1)

T is the volume of water transferred into the storage from the urban water system (line item 41.4)

 

Total outflow (O) is calculated using the following equation:


O = L + D + R

 

where:

L is leakage from the storage (line item 42.3)

D is volume of water diverted from the storage (line item 42.6)

R is volume of releases from the storage (line item 42.5)

Assumptions, Limitations, Caveats and Approximations

The evaporation and precipitation data for each storage used to calculate runoff was estimated by the Bureau. The assumptions and limitations associated with these data also apply here.

Uncertainty Information

The uncertainty estimate was not quantified.