BRS SEMINAR SERIES PRESENTS: Friday 14 July 2006

New insights into salinity in the Murray Darling BasinMary Colreavy — Natural Resource Management, DAFF

Scott Macaulay and Margaret Allan —Bureau of Rural Sciences, DAFF

Salinity is an important resource issue, with impacts on farm productivity and on the quality of our environment and natural

resources. More information on the sources of salt and freshwater in catchments is needed to better manage the problem. To gain a

better understand of salinity in the Murray Darling Basin (MDB), the Australian Government has provided $20 million for the Bureau of Rural Sciences to manage a series of community stream sampling

and salinity mapping projects across the region. Community based stream sampling investigations across 15

Catchment Management Organisations in the MDB will build a snapshot of salinity across the Basin, while detailed investigations

using airborne geophysical surveys will generate detailed three dimensional models of salinity and water process at a small number of critical sites. These results will be combined with an investigation of the social and environmental history of land use practices which will identify the salinity trends over time associated with land-use

changes and map them against current conditions.

Community Stream Sampling and Salinity Mapping in the Murray Darling Basin

Science for decision makers

Mary Colreavy – DEH

Margaret Allan, Scott Macaulay - BRS

www.brs.gov.au

National Action Plan for Salinity & Water Quality

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$20 million committed to salt mapping across the Murray Darling Basin

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Three stage approach

2) Airborne Geophysical Surveys across priority areas.

1) A network of community based stream sampling projects across the Murray Darling Basin

3) An investigation of social and environmental history of land use practices

Community Stream Sampling in the Murray Darling Basin

Science for decision makers

www.brs.gov.au

www.brs.gov.au

Stream Sampling Objectives

•Community involvement in identification of new areas where salt is being mobilised by surface water

•Collection of standardised and verifiable data

•Development of a comprehensive dataset for surface water salt mobilisation in the MDB

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Community Stream Sampling

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Community Stream SamplingCommunity participation in stream sampling is an effective way of identifying surface water salinity.

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Community Stream Sampling

Community groups will monitor EC of streams from major sub-catchments over the next 2 years.

EC (electrical conductivity) is a measure of dissolved salt in water.

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Outcomes

•Ranking of subcatchments based on salinity of surface water

•Information for decisions on salinity management

•Community access to data using web-based tools

•Community involvement in salinity monitoring and management

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Community Stream Sampling

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Goals

•Increased understanding of surface water salinity in the MDB to inform future management decisions.

•Promote community ‘awareness and ownership’ of the information and engagement with CMOs in the management of any salinity problems.

3D Salt and Groundwater Mapping

Science for decision makers

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AIRBORNE ELECTROMAGNETICS

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EXISTING & PROPOSED SALT-MAPPING AREAS

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MACQUARIE AIRBORNE GEOPHYSICS SURVEY AREA

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Excerpt from fat ducks, fat cattle – fat chance.Sydney Morning Herald 08 July 06

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SALT-MAPPING

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GROUNDWATER RESOURCE ASSESSMENT

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GROUNDWATER RESOURCE ASSESSMENT

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CLAY / SAND MAPPING

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MAPPING THE BLANCHETOWN CLAY

Blanchetown ClayHole

Overlying Sands

Saline Sands

Underlying Sands

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MAPPING THE BLANCHETOWN CLAY

www.brs.gov.au* Sydney Morning Herald 8 July 06

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SOCIAL & ENVIRONMENTAL HISTORY

Looking at the social and environmental history of the area.

Identify key-players, and equip them with the knowledge to manage salinity

Combine expert and local knowledge

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Summary

Salt in the landscape varies, both laterally and with depth.

Only salt mobilized by groundwater is a salinity risk.

Understanding where the salt is, is only part of the problem

Understanding groundwater movement & groundwater / surface-waterinteraction is vital.

No ‘one-size-fits-all’ approach. Ask the right questions and collect data that is fit for purpose

The most powerful tool we have is behavioural change.

www.brs.gov.au* Sydney Morning Herald 8 July 06

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