RB 2000/00036 Water resource assessment, Tatiara Prescribed Wells Area (For the South East Catchment Water Management Board).
Published: 01 Aug 2000 Created: 25 Nov 2024 Revised: 27 Nov 2024

The Tatiara Prescribed Wells Area (PWA) is about 250 km SE of Adelaide and covers about 3500 squ km. The PWA consists of a coastal plain to the west and the uplifted Pinnaroo Block to the east, referred to as the eastern highlands area. They are...

The Tatiara Prescribed Wells Area (PWA) is about 250 km SE of Adelaide and covers about 3500 squ km. The PWA consists of a coastal plain to the west and the uplifted Pinnaroo Block to the east, referred to as the eastern highlands area. They are separated by a fault scarp known as the Marmon Jabuk Scarp to the north and the Kanawinka Fault to the south. The fault has no surface definition in the PWA, being overlain by younger sedimentary deposits. The main water resource is the regionally unconfined Murray Group Limestone aquifer in the eastern highlands and the Padthaway Formation on the coastal plain. Groundwater flow is generally from east to west. In the eastern highlands groundwater flows mainly through the Murray Group Limestone. The depth to water can be in excess of 40 m, reflecting the elevated topography. Well yields from the aquifer range from 50 to 200 L/s. On the coastal plain the Murray Group Limestone is absent. Groundwater flow in the unconfined aquifer continues mainly through the Padthaway Formation and the underlying Bridgewater Formation. The depth to water on the coastal plain is generally less than 5m. Well yields can be up to 300 L/s. The unconfined and confined aquifers are separated by a relatively thick, low permeability aquitard, and so they can be managed independently. The confined aquifer also flows west across the Tatiara PWA. Recharge to the aquifer is predominantly via lateral throughflow, possibly originating from the Dundas Plateau in western Victoria. Depth to the confined aquifer formation is generally more than 100m. Well yields range between 10 and 20 L/s, but wells can produce fine sand when pumped. The water resources of the Tatiara area were proclaimed in 1984 following community concern about irrigation expansion. A study confirmed a long-term decline in water quality in the densely irrigated western portion of the region. A water balance for the unconfined aquifer suggests that the area is approximately in balance, if it were not for a significant decline in water levels in the densely irrigated western portion of the PWA. Groundwater salinity monitoring since the mid-1970s indicates a significant increase in groundwater salinity in PWA Management Sub-area 7, the Hundred of Stirling, and a more recent decline in the water table. Groundwater recycling due to overuse is believed to be the main cause of the salinity increase. In the eastern highlands the water table is rising slightly, as is the groundwater salinity. Increased recharge following land clearance is considered to be responsible. Efforts to mitigate the increasing groundwater salinity in the Hundred of Stirling by reducing the Permissible Annual Volume of groundwater extracted appear to be ineffective. Annual water use remains at about 25,000 ML/yr. At current levels of water use the resource is not sustainable. Generally the water level and salinity monitoring networks are adequate for the Tatiara PWA. The potential impacts that over-use of one groundwater resource would impose on another were considered only minor in the Tatiara PWA. However, there are potentially down-gradient impacts from the densely irrigated area in the western portion of the PWA.

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About this record

Record No d20009210
Topic Geoscientific Information
Type of Resource Document
Category Type
Document Type Departmental Publication - Hydrogeological Publication
Contributor South Australia. Department for Water Resources;Water Search Groundwater and Geological Consultants
Sponsor South-East Catchment Water Management Board
Tenement
Tenement Holder
Operator
Geological Province Murray Basin
Mine Name
Stratigraphy
Commodity
    Notes
    Geographic Locality: South-East;Keith;Bordertown;Willalooka;Hd of Stirling;Serviceton (Vic.)
    Doc No: RB 2000/00036

    Geographic Locality: South-East;Keith;Bordertown;Willalooka;Hd of Stirling;Serviceton (Vic.) Doc No: RB 2000/00036

    Language English
    Metadata Standard ISO 19115-3

    Citations

    Use constraints License
    License Creative Commons Attribution 4.0
    Persistent identifier https://pid.sarig.sa.gov.au/document/d20009210
    Citation Brown, K.;Cobb, M.A. 2000. RB 2000/00036 Water resource assessment, Tatiara Prescribed Wells Area (For the South East Catchment Water Management Board). Departmental Publication - Hydrogeological Publication. Government of South Australia.
    https://pid.sarig.sa.gov.au/document/d20009210

    Technical information

    Status
    Maintenance and Update Frequency
    Geographic Reference GDA2020 (EPSG:7844)
    Geo bounding box {"type":"Polygon","coordinates":[[[140,-36.5],[141,-36.5],[141,-35.5],[140,-35.5],[140,-36.5]]]}
    Purpose
    
                        
                        
    
                        
                      
    Lineage