Australia history Summary

History of the South East Drainage System - Summary

1. Introduction

The South East Region of South Australia is a highly modified landscape. Broad-scale land clearance and an extensive cross-catchment drainage system have converted what was once a wetland dominated landscape into agricultural production on a vast scale.

There is a long history of drainage in the South East. The first drains in the lower South East commenced in 1863 and the majority were constructed between 1949-1972 largely to remove waterlogging to maintain the region’s productivity and improve accessibility. More recently the lower South East drainage system is also being managed to enhance natural wetlands.

The majority of drains in the upper South East were constructed during the past 20 years as part of the Upper South East Dryland Salinity and Flood Management Program (USE Program). The USE Program was initiated in the early 1990s to address four main elements: drainage, vegetation protection and enhancement, saltland agronomy, and wetland enhancement and management

The South East drainage system (comprising both upper and lower South East drainage system) is unique in that it applies a multi-objective approach to water management at a landscape scale to achieve economic, social and environmental objectives.

Much of the regional economy of the South East has developed over time on the basis of a fully functioning drainage system. The South East drainage system (comprising 2589 kilometres of drains and floodways) is a critical part of the region’s economic and social infrastructure that supports the region’s capacity to undertake economic activity, maintain transport networks and protect highly valued natural environments.

The South East drainage system is operated and managed to enhance environmental and social values, and maximise agricultural productivity through:

· Exporting 250, 000 tonnes of salt from the South East region (when rainfall allows)

· Maintaining a 5-10 fold increase in agricultural productivity

· Facilitating regional economic productivity ($3 Billion/ annum)

· Delivering 26 Billion litres of water to the Coorong South Lagoon, under normal rainfall conditions

· Providing available environmental flows to 40, 000 hectares of connected wetlands in the upper South East

· Improving the working relationship between government agencies, local councils and key stakeholders

Drainage in the South East has a long and varied history - both in terms of arguments for and against drainage in general, and certain schemes in particular. The purpose of drains and the management of surface water in the landscape and who should pay has also been a point of contention.

Legislation and administration have also varied over this time. However, there has always been some form of managing authority, and supporting legislation with wide ranging powers to move water as required and enable construction works.

A map of the South East Drainage System is provided in Appendix 1.

A comprehensive history of the South East drainage system is available in two key documents:

· ‘Environmental Impact Study on the Effect of Drainage in the South East of South Australia, 1980, South Eastern Drainage Board

· ‘Upper South East Program – Project Review and Closure Report, 2011, Department for Water

These two reports form the basis of this summary document. Turner and Carter also provide a history of the events and personalities associated with 125 years of drainage in the South East of South Australia.

2. Discussion

2.1. Reasons for drainage

An explanation of the reasons for drainage in the South East must be considered in the context of the regional typology and hydrology, as well as the conditions prior to European settlement. A brief summary is provided in Appendix 2.