9.1 Precipitation on surface water

Supporting information

The volume reported (6,783 ML) represents the total precipitation falling onto surface water storages and weirs in the Adelaide region during the 2012–13 year.

Precipitation, itemised by each surface water storage and weir, is provided in the following table.

Precipiation on storages and weirs in the Adelaide region during the 2012–13 year

Surface water storage

Volume (ML)

Barossa Reservoir1


Barossa Weir2


Clarendon Weir3


Gorge Weir4


Gumeracha Weir5


Happy Valley Reservoir6


Hope Valley Reservoir7


Kangaroo Creek Reservoir8


Little Para Reservoir9


Millbrook Reservoir10


Mount Bold Reservoir11


Myponga Reservoir12


Onkaparinga Summit Reservoir13


South Para Reservoir14


Warren Reservoir15




6-12, 14-15 Precipitation calculation used dynamic surface area.
1-5, 13 Precipitation calculation used static surface area.

Quantification approach

Data source

National Climate Centre daily climate grids (rainfall), Australian Hydrological Geospatial Fabric (AHGF) waterbody feature class, Australian Water Resources Information System (AWRIS)—Water storages.

Provided by

Bureau of Meteorology.


Monthly precipitation data were produced by the Bureau of Meteorology. These were based on daily data from approximately 6,500 rain gauge stations and interpolated to a 0.05 degree (approximately 5 km) national grid (Jones et al. 2007).

Precipitation at each waterbody was estimated from the proportionally weighted average of grid-point cells that intersected each storage or weir (water feature). The precipitation volume was then estimated using the surface area of each waterbody. Surface area varied dynamically with changing storage level for storages, where the relationship between storage level and surface area has been derived. The surface area of storages was either calculated dynamically or was a static value produced from the AHGF (refer to previous table). The surface area of all weirs was a static value produced from the AHGF.


Assumptions, limitations, caveats and approximations

  • The precipitation estimates were subject to approximations associated with interpolating observation point data to a national grid detailed in Jones et al. (2007).
  • The dynamic storage surface areas calculated from the levels and capacity tables represent a monthly average and therefore will not capture changes that occur on a shorter temporal scale.
  • The use of the static default AHGF surface area is an approximation only. It represents the water features at capacity and therefore likely results in an overestimation of precipitation on the water features.
  • Precipitation was only estimated for the surface water storages and weirs (for which data were available) within the Adelaide region and does not include river channels.

Uncertainty information

The uncertainty estimate was not quantified.