Padthaway Water Allocation Plan

Padthaway Water Allocation Plan

If you have a water licence or are looking to get a licence in the Padthaway area you should understand the Padthaway Water Allocation Plan.

The current Padthaway Water Allocation Plan was adopted in 2009 and is a community based solution to over allocation in the Padthaway area. It establishes a framework for the sustainable management of groundwater resources. It provides for the allocation and trade of water for the current irrigation-dependent industries. It also protects the health of the resources and the ecosystems that rely on them.

It is the result of extensive planning, research and community consultation. The community took an active and leading role in the process.

Padthaway Water Allocation Plan [PDF, 4 MB]

The Limestone Coast Landscape Board develops and maintains water allocation plans as outlined in the Landscape South Australia Act 2019. The plans are developed with environmental, social, cultural and economic needs in mind and seek to ensure long term sustainability and security of the resource.

The Padthaway Water Allocation Plan is being amended

In 2019 a review of the Padthaway Water Allocation Plan began and a stakeholder advisory group was formed to assist in the process. The review resulted in the Padthaway Water Allocation Plan moving into an amendment process. This amendment process is currently underway. The draft Plan has been out to community consultation.

Find out more about the review and amendment of the Padthaway Water Allocation Plan

During the process to amend the Padthaway Water Allocation Plan all water licensing business will continue as per usual. The Department for Environment and Water Licensing Team are your contact for all licensing matters.

Water resources in the Padthaway Prescribed Wells Area

Water resources in the area consist of an unconfined aquifer and a confined aquifer. The upper unconfined aquifer is recharged through rainfall. A thick clay sits under the unconfined aquifer preventing recharge into the confined aquifer and connectivity between the aquifers.

The Padthaway Prescribed Wells Area supports just over 100 water licences.

Water resource in the unconfined aquifer

The unconfined aquifer is the primary water resource used in the area for public water supply, irrigation, recreation and industry. The unconfined aquifer is fully allocated. It is divided into 2 management areas, the Padthaway Flats and Padthaway Ranges.

Groundwater flows in a west to north-west direction from the Naracoorte Range, towards and along the flats in the west. The unconfined aquifer in the flats area generally has high well yields. Depth to water tends to range between 2 and 6 metres.

The unconfined aquifer in the ranges area to the east tends to have lower well yields and can produce fine sand when pumped.

Salinity in the Padthaway Prescribed Wells Area in the unconfined aquifer

Groundwater salinity trends are variable across the Padthaway Prescribed Wells Area. Some wells have shown declining or stable salinity trends whilst others have displayed an increasing salinity trend. Increasing trends in groundwater salinity are a combination of processes, including:

• Clearance of native vegetation between the 1950s and 1970s. This resulted in the flushing of salts from the unsaturated zone in the Padthaway Range. The natural underground water flow has mobilised this historic salt load into the Padthaway Flats.
• Evaporation and drainage of irrigation water (irrigation re-cycling) under flood irrigation.
• Flushing of high salinity soil under drip and pivot irrigation during periods of high rainfall.
• Evapotranspiration of groundwater where the water table is shallow.

The groundwater salinity in the Padthaway Flats ranges from 1,700 μS/cm to 3,700 μS/cm. It becomes far more saline (7,800 μS/cm to 15,800 μS/cm) toward the western margins.

The groundwater salinity in the Padthaway Range is generally lower than in the Padthaway Flats. Salinity ranges from 1,800 μS/cm to 3,100 μS/cm.

Water resource in the confined aquifer

The confined aquifer is absent or thin (less than 2.5 m in thickness) over much of the area. It has limited capacity and is poor yielding. Water is only available for unlicensed consumptive use (e.g. stock and domestic) and is currently only used for a small number of stock and domestic wells.

History of the Padthaway Water Allocation Plan

The current version of the Water Allocation Plan for the Padthaway Prescribed Wells Area was adopted on 26 April 2009.

In 2016 there was a review of the water allocation plans in the upper Limestone Coast. This review considered areas for improvement in the Tintinara-Coonalpyn, Tatiara and Padthaway water allocation plans. It also considered amalgamation of the three plans. The outcome of review was to not amalgamate the three plans and identified some areas for improvement.

A further review of the Padthaway Water Allocation Plan began in 2019 and the amendment process is currently underway.