Surface Water Assessment of the Upper Angas Sub-Catchment
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DWLBC REPORT Surface Water Assessment of the Upper Angas Sub-catchment 2006/09 Surface Water Assessment of the Upper Angas Sub-catchment Kumar Savadamuthu Knowledge and Information Division Department of Water, Land and Biodiversity Conservation February 2007 Report DWLBC 2006/09 Knowledge and Information Division 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 2006 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-13 978-1-921218-44-6 Preferred way to cite this publication Savadamuthu, K 2006, Surface water assessment of the Upper Angas sub-catchment, Report DWLBC 2006/09, 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 2006/09 iii Surface Water Assessment of the Upper Angas Sub-catchment Report DWLBC 2006/09 iv Surface Water Assessment of the Upper Angas Sub-catchment CONTENTS FOREWORD...........................................................................................................................iii EXECUTIVE SUMMARY .........................................................................................................1 1. INTRODUCTION...............................................................................................................5 1.1 PURPOSE AND SCOPE OF THE STUDY ................................................................5 1.2 BACKGROUND..........................................................................................................5 1.3 STUDY APPROACH ..................................................................................................6 2. CATCHMENT DESCRIPTION ........................................................................................13 2.1 OVERVIEW ..............................................................................................................13 2.2 CATCHMENT SUBDIVISION...................................................................................13 2.2.1 Major Sub-catchments .......................................................................................................14 2.2.2 Surface water Zones..........................................................................................................14 2.2.3 FARM DAM CATCHMENTS..............................................................................................15 2.3 LAND USE ...............................................................................................................15 2.4 FARM DAMS............................................................................................................16 2.4.1 NUMBER AND STORAGE CAPACITY OF DAMS............................................................17 2.4.2 DAM DENSITY...................................................................................................................18 2.4.3 DAM DEVELOPMENT LIMITS ..........................................................................................19 3. CATCHMENT HYDROLOGY .........................................................................................27 3.1 RAINFALL ................................................................................................................27 3.1.1 DATA AVAILABILITY AND PROCESSING .......................................................................27 3.1.2 DATA ANALYSIS...............................................................................................................27 3.2 STREAMFLOW ........................................................................................................30 3.2.1 DATA AVAILIABILITY AND QUALITY...............................................................................30 3.2.2 DATA ANALYSIS...............................................................................................................31 4. SURFACE WATER MODELLING ..................................................................................35 4.1 OVERVIEW ..............................................................................................................35 4.2 METHODOLOGY .....................................................................................................36 4.3 MODEL CONSTRUCTION.......................................................................................36 4.3.1 MODEL NODES.................................................................................................................36 4.3.2 CATCHMENT NODE INPUTS...........................................................................................37 4.3.3 DAM NODE INPUTS .........................................................................................................37 4.3.4 RAINFALL SPATIAL VARIABILITY ...................................................................................38 4.4 MODEL CALIBRATION............................................................................................38 4.4.1 CALIBRATION METHOD ..................................................................................................38 4.4.2 CALIBRATION RESULTS .................................................................................................38 4.4.3 CALIBRATION IMPROVEMENT .......................................................................................39 Report DWLBC 2006/09 v Surface Water Assessment of the Upper Angas Sub-catchment CONTENTS 5. SCENARIO MODELLING...............................................................................................43 5.1 CURRENT SCENARIO ............................................................................................43 5.1.1 METHODLOGY..................................................................................................................44 5.1.2 MODELLED STREAMFLOW DATA ..................................................................................44 5.1.3 SUMMER BASEFLOWS....................................................................................................48 5.2 PRE-FARM DAM DEVELOPMENT SCENARIO......................................................50 5.2.1 METHODOLOGY...............................................................................................................50 5.2.2 RESULTS AND DISCUSSION ..........................................................................................50 5.3 FUTURE SCENARIO 1: FARM DAM DEVELOPMENT TO RMCWMP LIMITS, WITHOUT DIVERSION LIMITS..................................................................56 5.3.1 METHODOLOGY...............................................................................................................57 5.3.2 RESULTS AND DISCUSSION ..........................................................................................59 5.4 FUTURE SCENARIO 2: FARM DAM DEVELOPMENT TO RMCWMP LIMITS, WITH DIVERSION LIMITS .........................................................................63 5.4.1 METHODOLOGY...............................................................................................................63 5.4.2 RESULTS AND DICUSSION.............................................................................................64 6. SUMMARY, CONCLUSIONS AND RECOMMENDATIONS ..........................................69 6.1 HYDROLOGICAL DATA ..........................................................................................69 6.2 CATCHMENT MODELLING.....................................................................................70 6.2.1 CALIBRATION RESULTS .................................................................................................70