Publication (Technical report): Spencer regions strategic water management study: Environmental flow criteria

Publication Type:	Technical report / Consultancy
Publication Name:	Spencer regions strategic water management study: Environmental flow criteria

Reference Information

Sheldon, F. (1999) Spencer regions strategic water management study: Environmental flow criteria. Technical Report April 1999, CRCFE, Canberra.

Optional Information

Attached document(s):

ISBN:
0957704860

Other information:

Macrohabitat:
Ephemeral lakes and streams
Lowland river and associated wetlands
Semi-permanent creeks and small rivers
Mound springs , ground water and paleosystems
-ecology, hydrology, conservation and environmental flows of each

Abstract:

The Spencer Region in South Australia spans a number of climatic zones with rainfall variability extreme across the region. The area is also characterised by high evaporation. To a large extent streamflow within the region reflects the rainfall variability. Streams are generally ephemeral with some fed by more constant groundwater flows (mound springs, springs and palaeochannels).

Historically it has been almost impossible to harness most of the streams in the Spencer Region due to the nature of the terrain and the high losses associated with evaporation. However, with the development of enhanced aquifer recharge techniques future harvesting of a proportion of these flows is not unreasonable. This report aims to summarise the ecological parameters to be considered in relation to water abstraction from streams in the region.

The report provides a literature summary of the aquatic habitat types of the Spencer Region in South Australia. Habitats are divided into:

Temporary streams and springs
Semi-permanent creeks and small rivers
Large lowland rivers and associated wetlands
Ephemeral lakes
Groundwater
Mound Springs
Palaeochannels

For each habitat type the general hydrology is described, conservation issues outlined and environmental flows issues and recommendations addressed.

Although essentially arid the Spencer Region contains a rich diversity of aquatic habitats with a number of endemic plants and animals. Although the region is vast many of the aquatic habitats are 'linked'. At low flows there may be hundreds of kilometres between pools of water whereas at high flows water extends along the channels to the terminus and laterally across vast floodplains. Most of the large and small rivers of the region provide inflows to one or more of the ephemeral lake systems, very few drain to the ocean. Thus, any changes in the hydrology of the streams or rivers will have implications for the ecology of the terminal lakes.

Providing adequate and sustainable environmental flows for these systems may well be impossible once development has taken hold. Even the use of an adaptive management ethos to manage water harvesting may not work. The time scales required for response by highly variable arid zone systems will be extreme and, thus, by the time a response is detected the level of development may well have exceeded all levels of sustainability. The challenge in environmental management of the variable aquatic systems of the Spencer Region will be in being able to identify, and protect, those aspects of the long-term flow regime that are essential to the sustainability of the system.

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