Adelaide
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

271

Barossa Weir2

14

Clarendon Weir3

41

Gorge Weir4

14

Gumeracha Weir5

110

Happy Valley Reservoir6

787

Hope Valley Reservoir7

188

Kangaroo Creek Reservoir8

260

Little Para Reservoir9

305

Millbrook Reservoir10

698

Mount Bold Reservoir11

953

Myponga Reservoir12

1,596

Onkaparinga Summit Reservoir13

63

South Para Reservoir14

1,055

Warren Reservoir15

428

Total

6,783


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.

Method

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.