Warren-Donnelly Water Plan open for public comment

The Western Australian Department of Water has released the Warren-Donnelly surface water allocation plan for a public comment period of three months. The plan sets out the department's direction for the future allocation and management of surface water in the Warren and Donnelly river basins which run through the Manjimup Pemberton districts of the South-West of Western Australia.

About the Water Allocation Plan

Rivers in the area include the Warren River and its tributaries; including Tone, Perup, Yerraminup, and Wilgarup rivers and Lefroy Brook, and the Donnelly River and its tributaries, including Barlee Brook. For allocation planning and licensing purposes, the department has divided the Warren-Donnelly area into 25 surface water resources, which are based on hydrological catchment boundaries.

In 2008, studies indicated that some surface water resources in the Warren-Donnelly area were at risk of over-allocation due to high levels of surface water use and particularly very high levels of on-channel infrastructure in some areas. To maintain sustainable use of surface water resources, the Department announced interim allocation limits in 2008, that effectively capped water use at current levels in the highly developed areas.

The plan sets out:

the allocation planning boundaries for surface water resources
how much surface water can be allocated
whether water is available
how the department will allocate and manage surface water in the area
water resource and water use management objectives
how the department will implement, evaluate and review the plan over time.

The plan includes new allocation limits, which define how much surface water is available in each surface water resource. The new allocation limits replace previous limits.

The plan sets out how the Department will evaluate the plan and assess if there is a need to review the plan. Any future plan will clarify options for increasing reliability of supply and may introduce updated management arrangements in line with new legislation, which is currently being reviewed and updated.

The department's Director Water Resource Use, Rob Hammond said the new water allocation limits would protect the existing irrigation industries and river ecosystems, especially in the face of a drying climate:

The plan provides for more available water with up to 24 GL available for new water use across the plan area, with around 18 GL of this in the Warren River basin.

The new allocation limits replace interim limits announced in 2008, with the department using information from 2008 and 2009 studies of hydrology, ecology and the impacts of farm dams to ensure sustainable water abstraction.

Importantly, salinity improvement objectives of the Warren River Basin will be complemented by the allocation limits set for five resources along the lower Warren River.

Under the current plan, once pending licence applications were processed, there would be no further water available for consumptive use from the Upper Lefroy and East Brook resources, and limited water available from the Smith Brook, Wilgarup and Manjimup Brook/Yanmah-Dixvale catchments.

There would also be no further water available for consumptive use from most of the lower Donnelly River and Unicup Lakes which are located in state forest or national park. However, Mr Hammond said water would be available for consumptive use from most of the other surface water resources.

The closing date for submissions on the plan is 5pm Monday 6th September 2010.