What the results tell us for Tumbarumba
Groundwater in Tumbarumba Shire is from a low yield system and is of drinking water quality. No detailed data were available on groundwater levels, use or quality.
The shire is located mostly within the Murray catchment, with north and north-eastern parts of the shire in the Murrumbidgee catchment. Water management planning in the latter catchment needs to consider surface water and groundwater resources as a single resource.
Groundwater flow is from a local flow system, mostly found within Palaeozoic rocks or Mesozoic rocks (Bureau of Rural Sciences 2000), mostly in sedimentary aquifers (Sinclair Knight Mertz 2003).
The shire is in a low yielding groundwater system (EPA 2000) and is entitled to draw 9888 megalitres of groundwater per year. Licensed extraction of groundwater is administered under the NSW Department of Infrastructure Planning and Natural Resources.
It is difficult to provide reliable data on groundwater use other than council's extraction. This is because generally no other groundwater extractors meter or monitor their groundwater use, as their water charges are levied on the assumption of full usage of the licensed entitlement (even if the entitlement is not drawn upon).
Only general data are available on trends in groundwater levels relevant to Tumbarumba Shire. The shire is located in the general vicinity of the southern parts of the Lachlan and Cowra groundwater subsystems which are associated with the Murrumbidgee and Murray catchments (Ife and Skelt 2004). Ife and Skelt (2004) concluded that groundwater levels in the Cowra groundwater subsystem generally declined over the decade 1990–2000 mostly as a result of irrigation induced downward leakage into the Lachlan subsystem.
In the Murrumbidgee–Murray Highlands, which are associated with both the Lachlan and Cowra groundwater subsystems in the Murray and Murrumbidgee catchments, groundwater levels in cleared agricultural landscapes declined as a result of the drought years of the 1990's. At the same time, groundwater levels in discharge areas were still rising, while highland forested areas exhibited no recharge or rising trends (Ike and Skelt 2004).
Ife and Skelt (2004) noted that water management planning in the Murrumbidgee catchment needs to consider surface water and groundwater as a single resource.
Most groundwater in the shire had salt concentrations of 0–1,000 mg/L, making it suitable for drinking (EPA 2000).
Ife and Skelt (2004) noted the potential for induced flows of saline groundwaters from fractured rock aquifers at the margins of the Murray Geological Basin in the Cowra groundwater subsystem. There is no indication of the extent to which this hazard applies to Tumbarumba Shire.
Managing groundwater demand
Water conservation measures
When surface water was under stress the NSW Department of Infrastructure Planning and Natural Resources reduced groundwater entitlements to licensed extractors and placed embargos on new groundwater extraction licenses.
Laws and policy
Laws recently passed in NSW, such as the Water Management Act 2000 and Catchment Management Authority Act 2003, were aimed in part at ensuring sustainable groundwater extraction. In June 2004, the Council of Australian Governments also targeted efficiency of groundwater systems as part of the National Water Initiative. The shire falls within the Murray-Darling Basin 'Cap' arrangements, which now aim to ensure that groundwater management is integrated with surface water management. For further details of these matters see Government laws and policies.
In 2002 the NSW Government put in place two new policies—the Groundwater Dependent Ecosystem Policy and the Groundwater Quality Management Policy—to supplement the 1997 Groundwater Quality Protection Policy dealing with allocation, protection and groundwater-dependent ecosystems.
Tumbarumba Shire falls mostly within the Murray Catchment Management Authority (CMA) area, with northern parts of the shire located in the Murrumbidgee CMA area. The Murrumbidgee CMA set water targets in its Catchment Blueprint 2003–04 (DIPNR 2004); the plan is intended to achieve sustainable groundwater extraction within its 10-year life span. To help achieve targets, the Murrumbidgee CMA appointed a Catchment Support Officer to the area with funding from the Natural Heritage Trust.
The extent to which activities under the above reforms affected water management in Tumbarumba shire during this reporting period was not assessed for this report.
About the data
Data supplied by Tumbarumba Shire Council and the NSW Department of Infrastructure Planning and Natural Resources.
Groundwater with less than 1000 milligrams of salt per litre is considered good quality and suitable for drinking water and most uses; groundwater with 1000–3000 milligrams of salt per litre is considered fair to poor and suitable for livestock, some domestic and limited industrial uses (EPA 2000; DLWC 1999).
One megalitre = one million litres
mg/L = milligrams per litre
Flow systems—Local groundwater flow systems "have recharge and discharge areas within a few kilometres of one another. They tend to occur within individual subcatchments, in areas of higher relief such as foothills to ranges." (Bureau of Rural Sciences 2000, page 4).
Bureau of Rural Sciences (2000) Australian Groundwater Flow Systems Contributing to Dryland Salinity, Bureau of Rural Sciences, Canberra.
Department of Infrastructure Planning and Natural Resources (NSW) (2004) Combined NSW Catchment Management Authorities Annual Report 30003/04, Vol 1: CMA Activities and Achievements, Department of Infrastructure, Planning and Natural Resources, Sydney, online at http://www.cma.nsw.gov.au and http://www.dipnr.nsw.gov.au.
Department of Land and Water Conservation (NSW) (1999) Groundwater Quality Protection Policy, Department of Land and Water Conservation, Sydney, on line at http://www.dnr.nsw.gov.au/water/pdf/nsw_state_groundwater_quality_policy.pdf.
DIPNR—see Department of Infrastructure Planning and Natural Resources (NSW)
DLWC—see Department of Land and Water Conservation (NSW)
Environmental Protection Authority (NSW) (2000) New South Wales State of the Environment 2000 Report, New South Wales Environmental Protection Authority, Sydney, online at http://www.epa.nsw.gov.au.
EPA—see Environmental Protection Authority (NSW)
Ife D and Skelt K (2004) Murray-Darling Basin Groundwater Status 1999–2000: Summary Report, Murray-Darling Basin Commission, Canberra, on line at http://www.mdbc.gov.au/nrm/groundwater/groundwater_status_report_19902000.
Sinclair Knight Mertz (2003) Projections of Groundwater Extractions Rates and Implications for Future Demand and Competition for Surface Water, Murray-Darling Basin Commission and CSIRO Australia, Canberra.