Transcript Let`s recap
Let’s recap… • definition of a resource and a region • importance of water as a resource in Australia • geographic characteristics of the Murray-Darling Basin region Regional Resources • A resource is anything which occurs naturally or is created by humans provided that people use it to satisfy a need or want. • Regions are areas of various scales that have characteristics and features that distinguish them from other areas according to the elements used to define them. • Governments and other organisations often use the concept of region for planning purposes e.g. allocation of resources and development of policies. • Resources found within regions mean different things to different people over place and time. E.g. water in the MDB is used by many different people for different things. Importance of water in Australia • Uneven distribution of rainfall- unreliable and seasonal • Driest inhabited continent average 480mm rainfall a year • Sustainable? Increasing population and demand. Used for agriculture (75%), pastoral, industrial, commercial and urban purposes. Australians use 350litres a day compared with Asia and Africa who use 50-100 litres. Domestic use Australia’s water users • Domestic (cook, clean etc) • Environmental (ecosystems, living species) • Economic (growing crops, animals, transportation on water, HEP) • Aesthetic (gardens, fountains, parks, ponds) • Recreation (on and around water) • Strategic (nations security and well being) • Spiritual (religious ceremonies) Describe the geographic characteristics and water resources of the Murray-Darling Basin region • • • • • • location- SE Australia, entire basin covers a regional scale of 1 million sq km, distributed across 5 states (SA, VIC, NSW, ACT, QLD). Source of the Murray located at 1430m in Great Dividing range, mouth enters Lake Alexandrina and Albert near Goolwa. Distance- catchment is 1250km wide and 1365km long (1/7th of total land size in Australia) Region- the drainage basin of the MDB Movement- the flow of water is from the north and east to the south-west, draining into progressively drier regions. Spatial association- the amount of rainfall declines towards the interior of the basin. There is a strong Spatial association between the regions of lower rainfall and increasing evaporation rates. Annual rainfall average across the basin is 480mm. Of this 94% evaporates, 2% soaks into the ground, and 4% becomes run. Water resources- irrigation channels, Wetlands e.g. Coorong, Barmah Forest, Lower Lakes, Hume dam Characteristics continued… • Population-approximately 2 million people • Climate- average rainfall 480mm, evaporation rate is 4x the rainfall, range of subclimates • Shape- low lying, saucer shaped depression, most elevation below 200m Where does the MDB gain its water from? Distribution of water resources/ types of water resources in MDB • Rainfall • Groundwater • Diversions from other basins Rainfall distribution • Turn to page 160 NP. Describe the spatial association between likelihood of drought and rainfall distribution What is Ground water? • Is the form of precipitation that infiltrates the ground and is stored beneath the saturated zone of the water table in aquifers. • Groundwater is located throughout the MDB, however it is the quality of water which dictates its use, and rate of use • Not all groundwater is useful. • Groundwater contributes 10-15% of the Basin’s water resource. • It is used mostly for irrigation. • The 65% of groundwater taken for irrigation, is taken from an area covering less than 20% of basin Ground water Groundwater Factors affecting groundwater consumption? • The rate of consumption of groundwater grows at about 4% per year. WHY? • Increasing reliance is due to expansion of irrigated agriculture, drought periods and greater regulation o surface water Diversions- water from outside the basin. • Release of water from Snowy Mountains Scheme into the Murray and Murrumbidgee rivers and transfers from the Glenelg River to the Wimmera River provide another 1200 GL per year for the MDB from outside the basin.