PORT HACKING Past and present of an estuarine environment by A. D. Albani 1,2 and G. Cotis 2 (photo D. Messent) Sutherland, NSW 2013 1. School of Biological, Earth and Environmental Sciences, University of New South Wales ([email protected]). 2. Port Hacking Management Advisory Panel (1984-2012), Sutherland Shire Council ([email protected]) ISBN number 978-0-7334-3376-4 This work is copyright. Apart from any use permitted under the Copyright Act 1968, no part may be reproduced by any process, nor may any other exclusive right be exercised, without the permission of Sutherland Shire Council and University of New South Wales. All photographs, maps and diagrams, except otherwise attributed, Copyright 2014 Alberto Albani and George Cotis 2 Content Introduction .……………………………………………………….….3 The Natural Environment.………………………………………..….4 The Past..……………………………………………….……4 The Present..………………………….……………….…...11 The Aquatic Environment….…………..…..... 11 Flora and Fauna............................................15 Shiprock Aquatic Reserve…........……….…. 19 Marine or Tidal Delta ………........……….…. 24 Cabbage Tree Basin.................................... 30 Deeban Spit …………….........................….. 36 The Catchment………………………...…….. 43 Fluvial Deltas……..………………….…..…… 64 Bundeena Creek (ICOLL)............................. 72 Deep Basins................................................. 76 Environmental issues……………………………….……. 80 The Ballast Heap………………….......................……… 83 The Human Environment………………………………….………. 85 Pre 1788…………………………………………………… 85 After 1788.………………………………………….……... 89 Early history……………………………….…. 89 Fishing …………………………..................... 92 Fish Hatchery ……………..…………………. 94 Shell grit gathering (mining)…………….… 97 Dredging…………………………….……… 100 Early settlers………………………………….105 Recreational activities…………………….. 107 Foreshore development……………………. 111 The Royal National Park………………….... 126 Planning challenges…………………………134 Plans of management……………….………139 Climate changes and sea level rise…….….143 List of Figures…………………………………………………..…..148 Extracts ………...…………………………………………….….…152 Photo Album Summary………………………….………………. 216 Appendices……………………………………………………….. 237 Please note the complete Photo Albums are available only in the CD- Rom version of this document. 3 Introduction This paper has been prepared to complement the Port Hacking Plan of Management and its updates. Its aim is to provide background information, and to provide in abbreviated form an understanding of Port Hacking’s origins and its dynamics. It contains Extracts from the Port Hacking Plan of Management (Sutherland Shire, 1992), the Port Hacking Marine Delta, Management Options (PWD, 86013), the Port Hacking Integrated Environmental Management Plan (2007) and additional recent research material. We gratefully acknowledge the support of Mr David Messent and Mr Les Bursill, Aboriginal Living Sites Survey Team, for some of the photographs and Ms Mary Dallas, "Sutherland Shire Council Aboriginal Cultural Heritage Study". We also express our thanks to the editing assistance of Mrs. Sue Cotis. Many published early works give a detailed account of events and the original written words disclose the style and depth of thought and the interrelation with the natural environment. For that reason we offer a comprehensive series of Extracts of original documents and narratives. To allow the flow of the discussion such Extracts are presented at the end of this paper for easier consultation. The use of bookmarks facilitates their use. Further there are three works that, because of their relevance and magnitude, have been attached as Appendices. Additional images of particular importance, to enhance description or to re- enforce the text on a subject, are grouped as a separate file in Photo Album. All figures are acknowledged; those without acknowledgement are by the authors. While the presentation has been divided into natural and human environments some overlapping is unavoidable. 4 The Natural Environment - The Past Port Hacking lies on the southern fringe of Sydney, 30 kilometres from the city proper (Fig. 1). Located between the unspoilt landscape of the Royal National Park to the south and the surfing beaches of Cronulla to the north, Port Hacking remains a relatively unspoilt waterway. Figure 1 - Port Hacking (photo D. Messent) Figure 2 - Climatic and sea level fluctuations during the last 1.8 million years. 5 During the last 1.8 million years, the Earth experienced a number of climatic fluctuations (Fig. 2), with conditions similar to the present (warm) (Fig. 2 red) alternating with periods characterised by glaciations (cold) (Ice Ages) (Fig. 2 blue). About 29% of the continental areas, mainly in the northern hemisphere, was covered by ice that caused a drop in the sea level to a maximum of 120 metres below the present (Fig. 2). During the last 1.8 million years therefore the sea level fluctuated several times between the present and 120 metres below the present. During the glaciation periods and the lower sea levels, large volumes of sediments were eroded from the river valleys and transported to the sea. During the warmer periods, as the ice melted, the sea rose to the present level drowning the valleys; waves and tidal currents remobilized the sediments that were then redeposited in the outer portion of the valleys. During the low sea level conditions, the coastline of the metropolitan area of Sydney, shown in figure 3 as bedrock contours below present sea level, was several kilometres to the east and was characterized by numerous river valleys. Many rivers can be recognised such as the Hawkesbury, Parramatta, and Botany Rivers. The Hacking River was part of the Georges and Cooks Rivers system that, flowing to the sea, cut a deep rocky valley on the inner shelf to about 6-8 kilometres east of the present shores. They can be seen converging in that process. Other rivers are present mainly on the drowned inner shelf and largely covered by sediments, although indications of their presence can be inferred from the present day cliffs and beaches, and by the remnant terrestrial processes. In figure 4 the ancient valleys of the Hacking and Georges Rivers, as they appeared 20,000 years ago, are shown as bedrock contours in metres below present sea level. 6 3 30 000 3 40 000 3 50 000 3 60 000 3 70 000 40 60 20 20 20 80 Bedrock 40 80 100 40 40 80 60 80 60 100 80 morphology 60 60 100 80 80 100 Hawkesbury River 100 80 100 80 20 as contours 40 20 60 40 100 in metres 40 40 20 Pitt Water below 62 80 000 80 62 80 000 Palm Beach 40 60 100 Avalon sea level 20 100 60 Bilgola 40 20 80 100 Newport 100 80 40 60 80 20 Mona Vale 100 60 80 40 20 60 100 80 100 62 70 000 62 70 000 Narrabeen 20 60 40 60 20 20 80 Long Reef 100 20 Dee Why 40 100 20 60 80 40 40 40 Harbord 20 100 60 80 Manly 60 62 60 000 60 62 60 000 20 Port Jackson 60 80 80 60 100 60 60 40 80 80 60 Vaucluse 80 80 20 40 100 100 60 80 Dover Heights 80 62 50 000 40 62 50 000 Bondi 20 60 80 100 Bronte 40 20 Cogee 60 60 80 100 20 40 Maroubra 80 100 Malabar The 60 80 Peak 20 40 100 80 62 40 000 (See bedrock map of 62 40 000 Botany Bay for details) 90 Botany Bay 20 40 60 Kurnell 80 100 20 40 Georges River 60 20 40 20 60 80 60 40 100 40 80 62 30 000 20 62 30 000 80 60 100 20 40 100 A.D. Albani et al. 2012 3 30 000 3 40 000 3 50 000 3 60 000 3 70 000 Figure 3 – The Sydney coastline, as it was 20,000 - 18,000 years ago. 7 151º 10' 30 40 50 BOTANY BAY 20 60 Airport Maroubra Bedrock morphology Kyeemagh 20 30 20 contours 70 in metres below 20 present sea level 40 20 30 30 Brighton-le-Sands 30 20 20 1 40 50 30 60 70 20 40 sandy rocky 20 coastline 20 10 coastline 40 80 30 30 40 50 40 30 1 km 30 50 30 3 40 ancient rivers 30 2 La Perouse 30 60 40 4040 1 Cooks River 2030 50 4 70 30 30 Sans Souci 10 40 20 2 Botany River 34º 50 20 34º 30 30 10 40 40 40 40 50 50 30 50 3 Towra River 6 60 60 30 50 70 Inscription 30 10 60 40 5 Bonna River 20 30 50 Pt. 4 40 6050 80 20 1 40 90 5 Kurnell River 30 40 50 30 100 70 40 60 40 30 64 Georges River 50 110 30 20 Kurnell 7 Osborne River 60 70 40 50 20 30 10 8 Hacking River 30 40 Boat 20 7 50 60 2 6 Harbour 70 80 90 100 110 Gymea 10 120 30 20 5040 40 30 20 30 40 Caringbah 10 20 50 N 30 60 90 60 70 70 70 90 90 40 80 2030 40 110 40 10 10 100 90 90 70 100 110 20 90 80 110 40 Cronulla 40 60 70 70 70 Tasman Lilli 50 60 40 50 40 Pilli 40 80 6 20 40 40 70 90 Sea Royal 40 8 30 100 40 20 40 110 National 40 Park 40 40 30 20 Bundeena Albani et al. 1977,1978,1981,1982,1988 151º 10' Figure 4 – Bedrock topography of the Georges-Cooks-Hacking Rivers 20,000 years before the present Except for Osborne Shoal and Merries Reef the valleys are now filled with sand, which extends above the water forming the Kurnell Peninsula. Figure 5 - The ancient river valley of the Hacking River. The highly silted estuary of Port Hacking owes its origin to the erosive power of the Hacking River, whose source is in the vicinity of Kellys Falls at Stanwell Tops, and, as discussed earlier, to the subsequent drowning of the river valley. The bedrock bottom of the Port Hacking valley, off Port Hacking Point, is at about 95 metres below current sea level (Fig.