CRC FOR CATCHMENT HYDROLOGY CSIRO LAND AND WATER FLINDERS UNIVERSITY OF SOUTH AUSTRALIA CRC FOR CATCHMENT HYDROLOGY REPORT 00/3 CSIRO LAND AND WATER TECHNICAL REPORT 18/00 April 2000 CHARACTERISATION AND RANKING OF BASINS IN THE MURRAY BASIN OF SOUTH-EASTERN AUSTRALIA

Foreword The CRC for Catchment Hydrology S2 project 'Managing Disposal Basins for Salt Storage within Irrigation Areas' was based on the premise that disposal basins are 'a fact of life' in the Murray-Darling Basin. Consequently there is a need for guidelines to site, design and manage them to minimise environmental and other problems. However, more than 190 existing basins were built when there were no such guidelines. Some were well designed and sited, some less so. It is important that we not only design better basins in future, but also maintain our existing basins in an appropriate fashion. In some cases, we may need to decommission them. This report describes a methodology for maintaining a portfolio of disposal basins and describes the minimum dataset for doing so. It is then possible to focus attention on those that present the greatest risk and for which more work may be needed. The example uses thirty existing basins. Our selection was most probably biased towards basins we have the most information about. Nonetheless, the attempt to rank them is thwarted by a lack of even minimal information. This is despite some recent work by AGSO in compiling information on existing basins. Because of the lack of information, the list here should be considered preliminary and used as a basis for further discussion on how we manage our existing basins. This is not an output from the MDBC-funded grant on on-farm and community basins in the Riverine Plains, although it complements that work. Executive Summary The disposal of large volumes of saline water from interception and irrigation drainage schemes is a critical part of all land and water management strategies. Saline disposal basins are a common approach used for disposal of saline water at the land surface. There are currently more than 190 disposal basins in the Murray-Darling Basin of Australia. The ever growing number of disposal basins and potential environmental impacts they may have means that we need to be able to assess and compare a large number of disposal basins across the entire Murray-Darling Basin in a consistent, efficient and timely manner. This report describes an example methodology that could be used to do this. A set of criteria are used to characterise and then rank a group of about 30 notable disposal basins in South Australia, Victoria and New South Wales. The criteria used within this study are an extension of …