GROUNDWATER RESOURCES OF THE GOVERNMENT OF WESTERN AUSTRALIA NORTHERN GOLDFIELDS, WESTERN AUSTRALIA HYDROGEOLOGICAL RECORD SERIES WATER AND RIVERS COMMISSION REPORT HG 2 1999 WATER AND RIVERS COMMISSION Hyatt Centre 3 Plain Street East Perth Western Australia 6004 Telephone (08) 9278 0300 Facsimile (08) 9278 0301 Cover Photograph: Lawlers Creek, northeast of Pinnacles Station GROUNDWATER RESOURCES OF THE NORTHERN GOLDFIELDS, WESTERN AUSTRALIA by S. L. JOHNSON, D. P. COMMANDER AND C. A. O’BOY Water and Rivers Commission Resource Investigations Division WATER AND RIVERS COMMISSION HYDROGEOLOGICAL REPORT SERIES REPORT HG 2 1999 Recommended Reference JOHNSON, S. L., COMMANDER, D. P. & O’BOY, C.A. 1999, Groundwater resources of the Northern Goldfields, Western Australia: Water and Rivers Commission, Hydrogeological Record Series, Report HG 2, 57p. Copies available from: Resource Investigations Division Water and Rivers Commission 3 Plain Street EAST PERTH WESTERN AUSTRALIA 6004 Telephone (08) 9278 0300 Facsimile (08) 9278 0586 ISBN 0-7309-7434-0 ISSN 1329-542X Text printed on recycled stock June 1999 Contents Abstract...........................................................................................................................................................................1 1 Introduction ..........................................................................................................................................................3 1.1 General ................................................................................................................................................................3 1.2 Location...............................................................................................................................................................3 1.3 Climate ................................................................................................................................................................3 1.4 Topography and drainage....................................................................................................................................3 1.5 Vegetation............................................................................................................................................................4 1.6 History of water supply.......................................................................................................................................4 1.7 Demand for water................................................................................................................................................6 1.8 Allocation and licensing......................................................................................................................................7 1.9 Previous investigations........................................................................................................................................7 1.9.1 Geology....................................................................................................................................................7 1.9.2 Mineral exploration..................................................................................................................................8 1.9.3 Groundwater ............................................................................................................................................8 2 Investigation programme .............................................................................................................................9 2.1 Assessment of existing information....................................................................................................................9 2.2 Geophysical survey.............................................................................................................................................9 2.3 Drilling and bore construction ..........................................................................................................................10 3 Geology.................................................................................................................................................................12 3.1 Regional setting.................................................................................................................................................12 3.2 Archaean............................................................................................................................................................12 3.3 Cainozoic...........................................................................................................................................................12 3.3.1 Early Tertiary sediments........................................................................................................................12 3.3.2 Alluvium ................................................................................................................................................15 3.3.3 Calcrete ..................................................................................................................................................15 4 Hydrogeology....................................................................................................................................................16 4.1 Groundwater occurrence...................................................................................................................................16 4.2 Alluvium............................................................................................................................................................16 4.2.1 Aquifer characteristics...........................................................................................................................16 4.2.2 Groundwater resources..........................................................................................................................17 4.2.2.1 Renewable ..............................................................................................................................17 4.2.2.2 Stored......................................................................................................................................18 4.3 Calcrete..............................................................................................................................................................19 4.3.1 Aquifer characteristics...........................................................................................................................19 4.3.2 Groundwater resources..........................................................................................................................19 4.3.2.1 Renewable ..............................................................................................................................19 4.3.2.2 Stored......................................................................................................................................19 4.4 Palaeochannel sand...........................................................................................................................................20 4.4.1 Aquifer characteristics...........................................................................................................................20 4.4.2 Recharge.................................................................................................................................................21 4.4.3 Groundwater flow..................................................................................................................................22 4.4.4 Discharge ...............................................................................................................................................22 4.4.5 Trends in groundwater salinity ..............................................................................................................23 4.4.6 Groundwater resources..........................................................................................................................24 4.4.6.1 Renewable ..............................................................................................................................24 4.4.6.2 Stored......................................................................................................................................25 4.5 Fractured-rock aquifers.....................................................................................................................................26 4.5.1 Aquifer characteristics...........................................................................................................................26 4.5.2 Groundwater resources..........................................................................................................................27 4.5.2.1 Renewable ..............................................................................................................................27 4.5.2.2 Stored......................................................................................................................................28 4.6 Groundwater salinity.........................................................................................................................................29 5 Groundwater development........................................................................................................................31