Top End Waterways Project Part 1 An Assessment of the Physical and Ecological Condition of the Daly River and its Major Tributaries Technical Report No TR99/10 J.J. Faulks Department of Lands, Planning and Environment Katherine, NT July 1998 Northern Territory Government Top End Waterways Project Part 1 An Assessment of the Physical and Ecological Condition of the Daly River and its Major Tributaries by J.J. Faulks Department of Lands, Planning and Environment Katherine, NT July 1998 Technical Report No TR99/10 i Technical Report No TR99/10 ISBN 0 7245 4801 7 The report on the Daly River Catchment consists of two parts: Part 1 Daly River Catchment – An Assessment of the Physical and Ecological Condition of the Daly River and its Major Tributaries Part 2 Daly River Catchment – Accompanying Sub-catchment Information The reports are available from the Parks and Wildlife Commission of the Northern Territory (PWCNT) Library and the National Library, Canberra, through interlibrary loan. The reports may also be obtained from the Katherine Regional Office of the Department of Lands, Planning and Environment (DLP&E). Inquiries should be addressed to: Regional Director Department of Lands, Planning and Environment PMB 123 Katherine, Northern Territory Australia 0851 Phone: (08) 8973 8100 Fax: (08) 8973 8122 © Department of Lands, Planning and Environment, Northern Territory 1998 Photograph front cover: Flora River, a major tributary of the Daly River (taken by Judy Faulks) Top End Waterways Project DALY RIVER CATCHMENT ii Acknowledgements The project commenced in February 1995 and has been partly funded by the National Landcare Program (now known as the Natural Heritage Trust). I was employed to undertake the field assessment of the Daly River and major tributaries; produce a database to store the information collected and assist with data analysis; and to produce a report and associated maps on the outcomes. The majority of the field surveys were conducted between June and November 1995; with the remaining surveys carried out April to May 1996, August 1996, October to November 1996 and August 1997. The following people assisted me with my field survey work: Angus Cameron (volunteer) Jesse the Jack (volunteer) Mathew Connelly Brent Whitworth Jim Cryer Sean Walsh (Parks and Wildlife Commission of the NT – PWCNT) Robert Hodges (Department of Lands Planning and Environment - DLP&E) Tundra Morscheck Miriam Lang (DLP&E) Debbie Telfer (DLP&E) At times the survey work was ‘challenging’, with not only crocodiles to contend with, but mudflats, tidal bores, rapids, fires and hot November weather. The helpfulness of everyone throughout the field surveys was extremely appreciated. The great sites and experiences will never be forgotten. During 1996 field surveys were also completed for the Victoria River and major tributaries and will form the basis of another report. The contribution made by the following people was very much appreciated: I am extremely grateful to Redgum Technology for the tireless effort made in designing and implementing the database and associated queries to my satisfaction. The GIS support and mapping were provided by Caroline Green and Renee McPhee, DLP&E (Katherine), whose attention to detail and expertise were extremely appreciated. Flow and water quality data was supplied by Doug Kinter and Bob Masters, DLP&E (Darwin). Support, information and water quality data, collected as part of the ‘Ausrivas Project’, was supplied by Jane Suggit, DLP&E (Darwin). Background information on water resources was supplied by various people within DLP&E (Darwin). Stream ordering was undertaken by Dave Williams, DLP&E (Darwin). Regrouping of landform information was undertaken by Miriam Lang, DLP&E (Katherine). Identification of the large quantity of vegetation samples was carried out by Diane Napier and the NT Herbarium (PWCNT). Presentation of the vegetation profiles was carried out by Debbie Telfer, DLP&E, based on vegetation sketches done by Caroline Green, DLP&E (Katherine). Support, information and comments were also supplied by a number of other DLP&E staff members within the Katherine and Darwin offices as well as PWCNT, DPI&F, Northern Territory University and Queensland DPI. I am very appreciative of the efforts made by the technical working group that was set up to review the stability and condition ratings used, so that they would reflect Northern Territory conditions more closely. I am grateful to the property owners/managers who allowed access to the survey sites located on their properties and provided background information on the rivers and creeks. Thanks also to Wolf Sievers (former Regional Director, DLP&E, Katherine) for recognising the need for such a project, for seeking initial funding and for providing continued support while in Katherine. Top End Waterways Project DALY RIVER CATCHMENT iii Table of Contents TABLE OF CONTENTS ACKNOWLEDGEMENTS ii LIST OF FIGURES v LIST OF TABLES vi LIST OF MAPS x EXECUTIVE SUMMARY xi Overview xi Summary of Daly River Catchment Condition xii Summary of Daly River Sub-catchments Condition xvi Conclusions, Broad Management Issues and Recommendations xix 1. INTRODUCTION 1 2. OVERVIEW OF THE DALY RIVER CATCHMENT 2 2.1 Location 2 2.2 Climate 2 2.3 Geomorphology and Landform 4 2.4 Vegetation and Important Habitat Areas 6 2.5 Land Tenure, Use and Management 8 2.6 Water Resources 10 2.7 Characteristics of the Daly River 14 3. METHODS 19 3.1 Background to Methodology 19 3.2 Scope and Limitations 19 3.3 Follow-up Surveys 20 3.4 Sampling Strategy 21 3.5 Survey Components 22 3.6 Data Analyses and Presentation of Information 25 4. CATCHMENT RESULTS 27 4.1 Reach Environs and Site Features 27 4.2 Channel Habitat Types, Diversity and Dimensions 28 4.3 Bank Condition and Stability 31 4.4 Bed and Bar Condition and Stability 32 4.5 Bed and Bank Sediments 33 4.6 Riparian Vegetation 35 4.7 Aquatic Vegetation 39 4.8 Instream and Bank Habitats 40 4.9 Overall Condition 41 4.10 Stream Flow 42 4.11 Water Quality 46 Top End Waterways Project DALY RIVER CATCHMENT iv Table of Contents 5. SUB-CATCHMENT RESULTS 50 5.1 Daly River 50 5.2 Chilling Creek 65 5.3 Hayward Creek 67 5.4 Fish River 70 5.5 Bamboo (Moon Boon) Creek 73 5.6 Green Ant Creek 76 5.7 Douglas River 78 5.8 Stray Creek 87 5.9 Bradshaw Creek 90 5.10 Dead Horse Creek 92 5.11 Fergusson River 95 5.12 Flora River 107 5.13 Katherine River 113 5.14 Limestone Creek 127 5.15 King and Dry Rivers 129 5.16 Seventeen Mile Creek 138 6. SUMMARY – DALY RIVER CATCHMENT 140 7. CONCLUSIONS, BROAD MANAGEMENT ISSUES AND RECOMMENDATIONS 143 REFERENCES 149 GLOSSARY 154 APPENDICES 160 Appendix A Evolution of Daly River Estuarine Plains 161 Appendix B Summary of Data Sheet Information 164 Appendix C Summary of the Condition and Stability Ratings 170 MAPS 179 Top End Waterways Project DALY RIVER CATCHMENT v List of Figures LIST OF FIGURES 2. OVERVIEW OF THE DALY RIVER CATCHMENT Figure 2.1 Mean Monthly Rainfall for Katherine (1942-1997) 2 Figure 2.2 Mean Monthly Rainfall for Mango Farm at Daly River (1980-1997) 2 Figure 2.3 Total Annual Rainfall for Katherine (1873-1998) 3 Figure 2.4 Total Annual Rainfall for Mango Farm at Daly River (1980-1998) 4 Figure 2.5 Salinity Profile of the Daly River after Flood Recession – 3-5 July 1984 16 Figure 2.6 Classification of Drainage Patterns 16 Figure 2.7 Longitudinal Profile for the Daly River and Three of its Major Tributaries (the Douglas, Flora and Katherine Rivers) 18 4. CATCHMENT RESULTS Figure 4.1 Mean Monthly Discharge Recorded for Daly River 44 Figure 4.2 Mean Monthly Discharge Recorded for Katherine River and Seventeen Mile Creek 44 Figure 4.3 Mean Monthly Discharge Recorded for Several Major Tributaries of the Daly River 44 Figure 4.4 Mean Monthly Discharge Recorded for Intermittent Tributaries within the Daly River Catchment 45 Figure 4.5 Mean Monthly Discharge for Several Smaller Tributaries of the Daly River 45 5. SUB-CATCHMENT RESULTS Figure 5.1 Changes in Channel Location along the Lower Tidal Section of Daly River 52 APPENDICES Figure A.1 Lower Daly River, showing the track of active channel migration, ancient shorelines and the 6000-year mangrove swamp region 161 Figure A.2 Schematic tidal river of the Northern Territory, showing characteristics of different river segments 162 Figure A.3 Channel segments of Adelaide, South Alligator and Daly Rivers 163 Figure A.4 Diagrammatic Representation of a River Channel Showing the Type of Information Collected During Cross-section Surveys 166 Figure A.5 Diagrams used in the Field to Estimate Percentage Cover for Riparian Vegetation, Aquatic Vegetation and Instream Habitat 168 Top End Waterways Project DALY RIVER CATCHMENT vi List of Tables LIST OF TABLES 2. OVERVIEW OF THE DALY RIVER CATCHMENT Table 2.1 Summary of Climate Data for Locations within the Daly River Catchment 3 Table 2.2 Major Geomorphological Units within the Daly River Catchment 5 Table 2.3 Katherine River – Recorded Floods 10 Table 2.4 Water Extraction Licences within the Daly River Catchment 11 3. METHODS Table 3.1 Condition and Stability Rating Categories 25 4. CATCHMENT RESULTS Table 4.1 Land Use Adjacent to Reach Environs 27 Table 4.2 Major Factors Contributing to the Disturbance of the Reach Environs 27 Table 4.3 Disturbance Levels along Reach Environs based on Subjective Ratings 27 Table 4.4 State of the Reach Environs 28 Table 4.5 Channel Habitat Types 28 Table 4.6 Channel Dimensions for each Habitat Type 29 Table 4.7 Upper Bank Dimensions for each Habitat Type 30 Table 4.8 Channel Type Diversity 30 Table