What are the uses of surface water in East Gippsland (Vic) and to what is it allocated?

Allocation for each SWMA represents the volume of the management area's surface water resources allocated for use both within the basin and for use in other SWMAs. The volume diverted is the total volume of the SWMA's surface water resources diverted for use both within the management area and for export to other management areas.

What are the uses of surface water in East Gippsland (Vic) and to what is it allocated?

Allocation for each SWMA represents the volume of the management area's surface water resources allocated for use both within the basin and for use in other SWMAs. The volume diverted is the total volume of the SWMA's surface water resources diverted for use both within the management area and for export to other management areas.

What are the sources of water within East Gippsland (Vic)?

PLEASE NOTE :

Options for conjunctive use:

The Water Act 1989 prescribes in considerable detail the setting up of Groundwater Supply Protection Areas (GSPAs), and the development of Groundwater Management Plans for these areas. On the other hand, it is silent on the question of Streamflow Management Plans (SMPs), which are developed in an informal arrangement between NRE and the rural water authorities. It is recognised that part of the function of SMPs is to apportion the baseflow between consumptive use and the environment.

Ideally, where there is a significant interaction between surface and groundwater systems, there should be some integration of groundwater and surface water planning and management processes.

The only conjunctive management of surface and groundwater resources currently in place in Victoria is in relation to on-farm water allocations in some locations, where total water use cannot exceed a set allocated volume, regardless of the source of the water.

Goulburn Murray Water currently has such a policy in place in some irrigation districts, particularly in those areas covered by salinity management plans, where infiltration of water to the groundwater can cause rising water tables and, subsequently, increased land salinisation. The implementation of the policy is still in its infancy and the data required to enforce this policy is currently not readily available (pers. comm. D Morrison (GMW) October 2000).

While current SYs for some GMUs take into consideration baseflows to rivers and lakes, and have reduced SYs to allow for the maintenance of these surface water flows,these allowances have been made on the basis of very limited information. The impact of groundwater use on river baseflow needs to be monitored to determine whether the assumptions that have been made are correct, and what management actions are required in order to ensure that surface water resources are not impacted on by the extraction of groundwater resources.

There a no groundwater resource management issues identified for this SWMA and subsequently GMUs have not been defined within the management area. This SWMA is a low priority basin in which there is no potential for conjunctive use. Many of the streams within the SWMA however, would interact with groundwater, and are possibly sourced from spring water in the upper catchment areas. The only groundwater use within the SWMA comes from the water table aquifer in the unincorporated area of the Gippsland Province.

Impediments to the conjunctive management of surface and groundwater resources are:

• insufficient data on groundwater levels and use;
• in most cases there is not satisfactory scientific quantification of surface environmental flow requirements;
• inadequate understanding of the significance of

PLEASE NOTE :

Options for conjunctive use:

climate variability (in particular floods) in influencing recharge;

• the need to establish appropriate conceptual models of how groundwater and surface water systems interact, on which to base the development of principles for the joint management of the resources; for example:
• the extent to which watertable level declines will affect stream baseflow is virtually universally unquantified, along with the levels at which rivers begin recharging aquifers, such as during high flow periods;
• little is known about the distance from a stream in which groundwater extractions should be limited to avoid adverse impacts on baseflow, or under what climatic conditions use in the stream and/or groundwater should be limited; and
• the lack of a formal statutory mechanism to allow for the joint management of surface water and groundwater.