Groundwater Recharge Investigations in the Eastern Mount Lofty Ranges, South Australia
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DWLBC REPORT Groundwater Recharge Investigations in the Eastern Mount Lofty Ranges, South Australia 2007/20 Groundwater Recharge Investigations in the Eastern Mount Lofty Ranges, South Australia Eddie Banks, Tania Wilson, Graham Green and Andrew Love Knowledge and Information Division Resource Investigation Group Department of Water, Land and Biodiversity Conservation June 2007 Report DWLBC 2007/20 Knowledge and Information Division Resource Investigation Group Department of Water, Land and Biodiversity Conservation 25 Grenfell Street, Adelaide GPO Box 2834, Adelaide SA 5001 Telephone National (08) 8463 6946 International +61 8 8463 6946 Fax National (08) 8463 6999 International +61 8 8463 6999 Website www.dwlbc.sa.gov.au Disclaimer The Department of Water, Land and Biodiversity Conservation and its employees do not warrant or make any representation regarding the use, or results of the use, of the information contained herein as regards to its correctness, accuracy, reliability, currency or otherwise. The Department of Water, Land and Biodiversity Conservation and its employees expressly disclaims all liability or responsibility to any person using the information or advice. Information contained in this document is correct at the time of writing. © Government of South Australia, through the Department of Water, Land and Biodiversity Conservation 2007 This work is Copyright. Apart from any use permitted under the Copyright Act 1968 (Cwlth), no part may be reproduced by any process without prior written permission obtained from the Department of Water, Land and Biodiversity Conservation. Requests and enquiries concerning reproduction and rights should be directed to the Chief Executive, Department of Water, Land and Biodiversity Conservation, GPO Box 2834, Adelaide SA 5001. ISBN 978-1-921218-62-0 Preferred way to cite this publication Banks, EW, Wilson, T, Green, G & Love, AJ 2006, Groundwater recharge investigations in the Eastern Mount Lofty Ranges, South Australia, Report DWLBC 2007/20, Government of South Australia, through Department of Water, Land and Biodiversity Conservation, Adelaide. FOREWORD South Australia’s unique and precious natural resources are fundamental to the economic and social wellbeing of the state. It is critical that these resources are managed in a sustainable manner to safeguard them both for current users and for future generations. The Department of Water, Land and Biodiversity Conservation (DWLBC) strives to ensure that our natural resources are managed so that they are available for all users, including the environment. In order for us to best manage these natural resources, it is imperative that we have a sound knowledge of their condition and how they are likely to respond to management changes. DWLBC scientific and technical staff continue to improve this knowledge through undertaking investigations, technical reviews and resource modelling. Rob Freeman CHIEF EXECUTIVE DEPARTMENT OF WATER, LAND AND BIODIVERSITY CONSERVATION Report DWLBC 2007/20 i Groundwater Recharge Investigations in the Eastern Mount Lofty Ranges, South Australia Report DWLBC 2007/20 ii Groundwater Recharge Investigations in the Eastern Mount Lofty Ranges, South Australia CONTENTS FOREWORD.............................................................................................................................i EXECUTIVE SUMMARY .........................................................................................................1 1. INTRODUCTION..............................................................................................................3 1.1 FRACTURED ROCK AQUIFERS.............................................................................3 1.2 AIMS AND OBJECTIVES.........................................................................................3 2. EMLR CATCHMENTS .....................................................................................................5 2.1 BURRA CREEK CATCHMENT ................................................................................5 2.1.1 Climate............................................................................................................................. 5 2.1.2 Geology ........................................................................................................................... 5 2.1.3 Hydrogeology................................................................................................................... 8 2.2 ANGAS RIVER AND FINNISS RIVER CATCHMENTS .........................................12 2.2.1 Climate........................................................................................................................... 12 2.2.2 Geology of the Angas and Finniss River Catchments................................................... 14 2.2.3 Hydrogeology of the Angas River and Finniss River Catchments ................................ 14 3. DRILLING PROGRAM...................................................................................................19 3.1 SITE SELECTION ..................................................................................................19 3.1.1 Burra Creek Catchment................................................................................................. 19 3.1.2 Angas River Catchment................................................................................................. 20 3.2 DRILLING ...............................................................................................................20 4. METHODOLOGY...........................................................................................................23 4.1 INTRODUCTION ....................................................................................................23 4.2 FIELD INVESTIGATIONS ......................................................................................23 4.3 PIEZOMETER INSTALLATION..............................................................................24 4.4 GROUNDWATER AGES AND DEPTH OF CIRCULATION...................................25 4.4.1 Major chemistry and isotopes........................................................................................ 25 4.4.2 Carbon-14 and Chlorofluorocarbons (CFCs) ................................................................ 26 4.5 VERTICAL FLOW RATES AND AQUIFER RECHARGE.......................................27 4.5.1 Carbon-14 and Chlorofluorocarbons (CFCs) ................................................................ 27 4.5.2 Aquifer pumping tests.................................................................................................... 28 4.5.3 Chloride mass balance .................................................................................................. 28 4.6 HORIZONTAL FLOW VELOCITIES.......................................................................29 4.6.1 Radon ............................................................................................................................ 29 5. FIELD INVESTIGATIONS..............................................................................................31 5.1 BURRA CREEK CATCHMENT ..............................................................................31 5.1.1 Fracture analysis ........................................................................................................... 31 5.1.2 Electrical conductivity, temperature and pH in open wells ............................................ 31 5.1.3 Geophysical and EM flow surveys in open wells........................................................... 32 5.1.4 Hydraulics ......................................................................................................................33 5.2 ANGAS RIVER CATCHMENT................................................................................34 5.2.1 Fracture analysis ........................................................................................................... 35 5.2.2 Electrical conductivity, temperature and pH in open wells ............................................ 36 Report DWLBC 2007/20 iii Groundwater Recharge Investigations in the Eastern Mount Lofty Ranges, South Australia CONTENTS 5.2.3 Geophysical and EM flow surveys in open wells........................................................... 37 5.2.4 Hydraulics ......................................................................................................................38 5.3 FINNISS RIVER CATCHMENT..............................................................................39 5.3.1 Fracture analysis ........................................................................................................... 39 5.3.2 Electrical conductivity, temperature and pH in open wells ............................................ 40 5.3.3 Geophysical and EM flow surveys in open wells........................................................... 41 5.3.4 Hydraulics ......................................................................................................................42 6. GROUNDWATER AGES AND DEPTH OF CIRCULATION .........................................45 6.1 BURRA CREEK CATCHMENT ..............................................................................45 6.1.1 Major chemistry and isotopes........................................................................................ 45 6.1.2 Carbon-14 and Chlorofluorocarbons (CFCs) ................................................................ 48 6.2 ANGAS RIVER CATCHMENT................................................................................52