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Great Sandy Strait catchment story

The catchment stories present a story using real maps that can be interrogated, zoomed in and moved to explore the area in more detail. They are used to take users through multiple maps, images and videos to provide engaging, in-depth information.

Quick facts

This map journal
is part of a series of catchment stories prepared for Queensland.

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This map journal is part of a series prepared for the catchments of Queensland.

We would like to respectfully acknowledge the Butchulla, Kabi Kabi and Jinibara (Wakka Wakka) peoples, the First Nations peoples of the land and waters on which this project takes place, and Elders both past and present. We also recognise the ongoing effort to protect and promote Aboriginal and Torres Strait Islander cultures, which will leave a lasting legacy for future Elders and leaders.

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Table of contents

  1. Understanding how water flows in the catchment
  2. How to view this map journal
  3. Overview of the catchments
  4. First Nations peoples
  5. Values of the Strait and surrounding catchments—economic and social
  6. Values of the Strait and surrounding catchments—natural features
  7. Values of the Strait and surrounding catchments—wetlands
  8. Great Sandy Strait Ramsar site
  9. Great Sandy Biosphere
  10. Physical features—geology and topography
  11. Physical features—rainfall

Main image. Tin Can Inlet, southern Great Sandy Strait, Photo by Gary Cranitch ©Queensland Museum.

Understanding how water flows in the catchments

To effectively manage a catchment it is important to have a collective understanding of how the catchment works. This map journal gathers information from experts and other data sources to provide that understanding.

The information was gathered using the ‘walking the landscape’* process, where experts systematically worked through a catchment in a facilitated workshop, to incorporate diverse knowledge on the landscape features and processes, both natural and human. It focused on water flow and the key factors that affect water movement.

The map journal was prepared by the Queensland Wetlands Program in the Queensland Department of Environment and Science in collaboration with local partners.

*Walking the Landscape—A Whole-of-system Framework for Understanding and Mapping Environmental Processes and Values (Department of Environment and Heritage Protection 2012) - see links at the end of this map journal for further information.

How to view this map journal

This map journal is best viewed in Chrome or Firefox, not Explorer.

  • Use the tabs across the top of the page to explore the ‘catchment story’.
  • Use the side navigation bar (series of dots) to explore each tab.
  • Click on the coloured text to see more information about that topic.
  • In the map area, click on features you see, zoom in and out, pan around and expand the Legend (drop down box at top right of map window) for more information.
  • Images and graphics can be expanded by clicking the icon at the top right corner of the image/graphic.
  • YouTube videos may also be used to portray information. Wait for them to load, and pause and play as needed by clicking in the middle of the screen.

Main image. Booloumba Creek and camping area, Photo by Tourism and Events Queensland.

Overview of the catchments

The Great Sandy Strait (the Strait) is a 70 kilometres long sand passage estuary with tidal openings to Hervey Bay and Wide Bay. It receives water from the Mary and Susan catchments, the mainland coastal catchments including part of the Cooloola sand mass, and south-western K'gari (Fraser Island).

The Mary River, Photo by Tourism and Events Queensland.

Many waterways flow to the Strait (click for animation) including:

  • the Mary River and tributaries,
  • the Susan River and tributaries,
  • coastal waterways on the mainland such as Pulgul Creek in the north, Kalah, Big Tuan and Poona creeks centrally and Kauri, Snapper, Cooloola and Searys creeks in the south, and
  • coastal waterways on K'gari such Yidney, Poyungan and Wanggoolba creeks in the northern Strait, and Tumbowah and Geewan creeks in the southern Strait.

Groundwater systems also contribute freshwater to the Strait, mostly in association with the Cooloola and K'gari sand masses and other porous geologies. The Strait adjoins Hervey Bay and the Great Barrier Reef in the north, and Wide Bay and the Coral Sea in the south.

K'gari sand mass, Photo by Department of Environment and Science, Queensland Government.

On western K'gari, waterways such as Wathumba, Bowarrady and Coongul creeks flow to Hervey Bay. On eastern K'gari, waterways flow to the Coral Sea, such as Akuna and Eli creeks in the north and Govi and Taleerba creeks in the south.

Within the Strait itself, tidal waters enter slowly from the north through Hervey Bay and from the south through Wide Bay. It takes much longer for the tides to go around the northern end of K'gari and through Hervey Bay, and there is a 'dead' energy (amphidromic) zone around the mud islands from Turkey to Moonboom islands and the Sheridan Flats.

The surrounding catchments are much larger than the Strait itself and contribute large volumes of freshwater to the Strait. The surrounding catchments extend from Sandy Cape in the north to the southern headwaters of the Mary River in the Sunshine Coast hinterland, and from Indian Head and Double Island Point in the east to the western headwaters of the Mary River near Kilkivan and Malarga.

The surrounding catchments cover approximately 12,230 square kilometres, and the Strait itself covers approximately 930 square kilometres.*

Dairy farming, Maleny, upper Mary River, Photo by Tourism and Events Queensland.

The Strait and surrounding catchments are managed by organisations including the Burnett Mary Regional Group (BMRG) Natural Resource Management (NRM) region and the Mary River Catchment Coordinating Committee (MRCCC).** The catchments fall mostly within the Fraser Coast and Gympie regional council areas, but also include parts of the Sunshine Coast Regional, Somerset Regional and Noosa Shire council areas.

Butchulla people traditional ceremony, Photo by Butchulla Aboriginal Corporation.

First Nations peoples of the Great Sandy Strait catchments include the Butchulla, Kabi Kabi  and Jinibara (Wakka Wakka) peoples*** and there are important cultural heritage sites across the catchments. First Nation groups worked together collectively to care for Country, they would meet, share and trade with neighbouring Nations in times of plenty. Butchulla and Kabi Kabi people used their traditional ecological knowledge developed over thousands of years of living closely with the environment to sustainably manage the Great Sandy Strait and surrounding catchment up until colonisation. Butchulla people continue to play a role in the management of the Great Sandy Strait and catchments.

Maryborough, Photo by Department of Environment and Science, Queensland Government.

The catchments include the towns of Gympie, Maryborough and parts of Hervey Bay, together with many townships such as Maleny, Kenilworth, Cooroy, Kandanga, Kilkivan, Brooweena, Tin Can Bay and Rainbow Beach.

Forestry, Amamoor, Photo by Department of Environment and Science, Queensland Government.

The catchments are dominated by conservation and natural uses, grazing (mostly on native pastures) and forestry. Large areas are protected by national park. K'gari is World Heritage-listed, and the Strait is within the Great Sandy Marine Park^ and Great Sandy Strait Ramsar site.

The Mary River is a Great Barrier Reef (GBR) catchment. Sediments from the Mary River can enter the GBR lagoon during large floods with flow-on effects to flora and fauna such as corals, seagrass, turtles and dugongs.^^ The GBR is also World Heritage-listed and a Commonwealth and State^^ marine park.

The catchments of the Great Barrier Reef - taken from Department of Environment and Heritage Protection (2016).^^^

National park signage, Photo by Tourism and Events Queensland.

The catchments are adjacent to the Burrum, Gregory, Burnett, Brisbane, Stanley and Noosa catchments. There are hydrological connections between these coastal catchments through surface flow and groundwater.

There is a drop-down legend for most maps and it can be accessed by clicking on 'LEGEND' at the top right of the map. On this map you can use the drop down legend for the land use.

There are also 'pop-ups' for most mapping features - simply click on the mapping of interest for more information.

Main image. Sand track through forest, K'gari, Photo by Department of Environment and Science, Queensland Government.

*based on area of Great Sandy Strait Ramsar site.

See links at the end of this map journal for further information on the following resources.

**The Mary River Catchment Coordinating Committee operates across the Mary River catchment area (Mary River Catchment Coordinating Committee undated).

***Cultural Heritage Portal (Department of Aboriginal and Torres Strait Islanders Partnerships 2020).

^Great Sandy Marine Park (Queensland Government 2019). Zoning is the primary tool used to manage different activities in the Great Sandy Marine Park (GSMP) and to separate potentially conflicting uses, while maintaining the park’s unique biodiversity. The GSMP has a zoning plan setting out the zones and other special management requirements in the marine park. These plans are developed and altered with input from First Nations peoples and user groups. There are four major zone types that apply to Queensland marine parks such as the GSMP:

  • General Use (light blue) – allows for a range of activities including trawling.
  • Habitat Protection (dark blue) – sensitive habitats with no trawling permitted.
  • Conservation Park (yellow) – limited fishing and crabbing.
  • Marine National Park (green) – high conservation value, 'look but no take' (Queensland Government 2019).

^^2013 Scientific Consensus Statement Land use impacts on Great Barrier Reef water quality and ecosystem condition (Brodie et al. 2013); Wetlands in the Great Barrier Reef Catchments Management Strategy 2016—21 (Department of Environment and Heritage Protection 2016); 2017 Scientific Consensus Statement Chapter Two: Sources of sediment, nutrients, pesticides and other pollutants to the Great Barrier Reef (Bartley et al. 2017).

^^^The GBRMP zoning 'defines the activities that can occur in which locations. The level of protection increases from the General Use (Light Blue) Zones up to the most restrictive, Preservation Zone. Each zone has different rules for the activities that are allowed, the activities that are prohibited and the activities that require a permit. Zones may also place restrictions on how some activities are conducted. There are eight different types of zones that apply to the entire GBRMP. The major zones are:

  • General Use (Light Blue)
  • Habitat Protection (Dark Blue)
  • Conservation Park (Yellow)
  • Marine National Park (Green).

Other zones include Preservation (Pink), Scientific Research (Orange), Buffer (Olive Green) and Commonwealth Island Zones, which make up less than five per cent of the Marine Park.' (Great Barrier Reef Marine Park Authority 2018).

The Great Barrier Reef Coast Marine Park (GBR Coast MP) is a State marine park that runs the full length of the GBRMP. It provides protection for Queensland tidal lands and tidal waters. The GBR Coast MP complements the GBRMP through adopting similar zone objectives, and entry and use provisions (Queensland Government 2018).

First Nations peoples

The Great Sandy Strait has evidence of many thousands of years of Traditional Owner occupation and there are special places of significance for food, materials and spiritual values. These include fish traps, midden sites, stone scatters, knapping floors (tool shops), stone tool kits, ceremonial areas, spiritual areas, pathways and scar trees.

Stone flake, Photo by Butchulla Aboriginal Corporation.

Butchulla culture relies on the ability to access Country physically and spiritually. Country needs to be healthy for Butchulla people to be able to practice many cultural activities, and share knowledge with younger generations. Many important aspects of Butchulla culture are linked to water, for example creation stories, dreaming and connecting to country activities like fishing and hunting. Butchulla peoples health and wellbeing are intrinsically linked to health of country and our ability to practice and share culture.

K'gari, the Butchulla name for Fraser Island, is based on the island's creation story. Biral, the great God in the sky, made all the people. But after he made the people, Biral realised that the people had no lands! So Biral sent a messenger, Yindinjie, to solve the problem and create lands for the people. When Yindinjie arrived at what is now known as Hervey Bay, he had a helper—the beautiful white spirit, Princess K'gari.

K'gari helped Yindinjie to make the sea shores, the mountain ranges, the lakes and the rivers. Princess K'gari enjoyed her work and worked tirelessly to create all this natural beauty. One day Yindinjie was concerned, and said to her, 'K'gari, you better rest, otherwise you will be too tired to continue our work. There are some rocks over there in the sea. Why don't you go and lie down and have a sleep?'

So K'gari lay down on the rocks and had a long and deep sleep. When she awoke she said to Yindinjie, 'I think this is the most beautiful place we have ever created. Please, Yindinjie, may I stay here forever?'

Yindinjie was reluctant, telling K'gari that she was a spirit and belonged with him, but K'gari pleaded with him.

'Please, please, Yindinjie ... I could still look up into the sky and see what you are doing. I would love to stay here.'

Finally, Yindinjie agreed. 'You may stay here, but you cannot stay in spirit form. I will need to change you.' So, he changed her into a beautiful island.

To prevent her from becoming lonely, he made some beautiful trees and flowers, and some lakes that were specially mirrored so that she could see into the sky. He made creeks and laughing waters that would become her voice, and birds and animals and people to keep her company. He gave these people knowledge and lores, and told them what to do, and how to procreate, so that their children and ancestors would always be there to keep K'gari company.

K'gari is still here today, looking at one of the most beautiful places on earth.

Butchulla Laws/Lores underpin the sustainable management of Country and Butchulla way of life. Three Butchulla lores are described below:

    1. Minyang galangoor gu djaa, kalim baya-m—What is good for the land comes first. 

      Butchulla people only took what was necessary for food, to avoid over-harvesting of animals and plants they relied upon for survival. Even today, scarce resources are protected, in line with customary practices, including totem systems which forbid the taking of certain species

    2. Minyang waa nyinung, waa bunmalee dhama-n—If you have plenty you must share.

      Respect for the rights of others was and remains integral to the Butchulla way of life. Women and men guard their own knowledge and sacred sites, and different clans had different responsibilities for and rights over certain species or areas of Country.

    3. Wangou nyin gamindu biralunbar, nyin wumga-n—Do not touch or take anything that does not belong to you.

      Butchulla people have a long history of welcoming and managing visitors on Country. Each Walai Walai Djau (winter season) when there was an abundance of certain fish (tailor, mullet) in the Great Sandy Strait waters, neighbouring Nations would come and share in times of plenty. They sought permission from Elders to cross the Great Sandy Strait and enter onto K’gari on the western side of the island. Throughout the seasons numbers would swell to a couple of thousand people. All visitors were expected to abide by Butchulla lore, whilst on Butchulla Country.

    Main image. Butchulla Community Ranger, Photo by Butchulla Aboriginal Corporation.

    Values of the Strait and surrounding catchments—economic and social

    A range of different land use types combine to make up the land use of the surrounding catchments. Land use is dominated by conservation and natural areas in the east, including Defence land, and grazing (mostly on native pastures) in the west. There are also large areas of forestry, together with other farming, residential areas and other minor land uses.

    Upper Mary catchment, Photo by Tourism and Events Queensland.

    The Mary catchment has large areas of fertile soils that support peri-urban living associated with grazing or other farming. Farming in the Mary River and mainland catchments includes grazing, cropping (sugar), horticulture (fruits, berries, nuts, vegetables, turf) and animal production (dairy, aquaculture, horse studs, piggeries and poultry).

    Imbil State Forest, Photo by Department of Environment and Science, Queensland Government.

    Forestry is also important to the Mary and mainland catchments, with large areas of plantation and native forests.

    Linear infrastructure such as roads and tracks, railways and pipelines are an important component of the economy.

    The Mary Rattler tourist train, Photo by Tourism and Events Queensland.

    Tourism is important to the local economy. Many international and national tourists visitor the area, particularly for camping and four wheel driving on K'gari, whale watching on Hervey Bay, and boating and fishing in the Strait. Seasonal employment also brings large numbers of international backpackers to the region.

    Tourism, Photo by Tourism and Events Queensland.

    The intertidal and subtidal systems of the Strait and its tributaries support commercial and recreational fisheries including reef fishes, estuarine fish such as barramundi and grunter, and crustaceans such as prawns and mud crabs. These sheltered waters are particularly popular for fishing.

    Wongari (dingo) with fish, Photo by Jenna Tapply, Queensland Government.

    The coastal waters along the eastern shore of K'gari support fisheries such as tailor, mullet, mackerel and reef fishes, and K'gari's north-western shore (Hervey Bay) supports a wide range of fisheries species.

    Butchulla (and other Nations) also have an economic value of the Great Sandy Strait and surrounding catchments.

    Whale exhibition, Urangan boat harbour, Hervey Bay, Photo by Tourism and Events Queensland

    Main image. Farming, Photo by Tourism and Events Queensland.

    Values of the Strait and surrounding catchments—natural features

    Scarlet percher dragonfly, Lake Boomanjin, Photo by Jenna Tapply, Queensland Government.

    The Strait and surrounding catchments support many important plants and vegetation communities, and provide habitat a wide range of fauna. Many of these species and communities are of conservation significance.

    High values of the systems have been recognised through the presence of:

    • several large national parks, with the largest being Great Sandy National Park, and other areas protected by the state,*
    • the K’gari World Heritage area (WHA),
    • the Great Sandy Strait Ramsar site,
    • the Great Sandy Marine Park,**
    • nature refuges,*
    • the Directory of Important Wetlands of Australia (DIWA),
    • declared fish habitat areas (FHAs),
    • the Hervey Bay—Tin Can Bay Dugong Protection Area,
    • the Great Sandy Biosphere Reserve,*** and
    • K’gari forests within the Queen's Commonwealth Canopy (QCC) project.^

    Large duck orchid, Photo by Jenna Tapply, Queensland Government.

    Main image. Humpback whale with calf, Photo by Gary Cranitch ©Queensland Museum.

    *Protected areas of Queensland are those set aside for the conservation of natural and cultural values or for production of resources, including timber and quarry material. The mapped nature refuges are areas gazetted through a voluntary conservation agreement between the state government and private land owners.

    **Great Sandy Marine Park (Department of Environment and Science 2019).

    ***Biosphere map provided by Burnett Mary Regional Group.

    ^The QCC is a unique network of forest conservation initiatives, which involves all 53 countries of the Commonwealth. It 'presents a rare opportunity to unite the whole Commonwealth family and save one of the world’s most important natural habitats – forests. By creating a pan-Commonwealth network of forest conservation projects, the QCC will mark Her Majesty The Queen’s service to the Commonwealth while conserving indigenous forests for future generations.' (©The Queen's Commonwealth Canopy, undated).

    Values of the Strait and surrounding catchment—wetlands

    The Strait and surrounding catchments support extensive freshwater and intertidal and subtidal (estuarine and marine) wetland systems.

    Patterned fens north of Wathumba Creek, K'gari, Photo by Gary Cranitch ©Queensland Museum.

    Freshwater systems include:

    • large palustrine wetlands (swamps), particularly in the undulating landscape of the Susan and mainland coastal catchments, and on K'gari,
    • extensive riverine wetlands, particularly across the Mary catchment,
    • lacustrine wetlands (lakes), with several relatively large lakes on K'gari, and
    • large areas of ‘contains wetlands’.*

    Intertidal and subtidal systems include:

    • intertidal wetlands such as trees (casuarinas and some melaleucas), grasses, herbs, sedges, mangroves, saltmarshes, salt pan, seagrasses, rocky shores, coffee rock, boulders, gravel, sand and mud, and
    • subtidal wetlands such as seagrasses, algae, corals, other invertebrates, rocky shores, coffee rock, boulders, gravel, sand and mud.

    Intertidal wetland, River Heads, Photo by Maria Zann.

    Freshwater systems support diverse fish, frog, bird, butterfly and plant communities. K'gari is the largest sand island in the world and the sand system supports extensive wetlands and groundwater dependent ecosystems (GDEs), including patterned fens, perched and window lakes (lacustrine wetlands), wallum heath and other palustrine wetlands and tannin-stained creeks.

    These GDEs require access to groundwater on a permanent or intermittent basis to meet all or some of their water requirements so as to maintain their communities of plants and animals, ecological processes and ecosystem services**. Ecosystem dependency on groundwater may vary temporally (over time) and spatially (depending on its location in the landscape).

    Lowland wetlands support waterbird (including shorebird) roosting, feeding and breeding areas and are important for both abundance and species diversity. Many of these waterbirds are migratory and protected under the Ramsar Convention and other international treaties (e.g. JAMBA, CAMBA, ROKAMBA), together with state and commonwealth legislation.

    Butchulla people use wetlands to gather food, and also understand that it is important habitat for young and juvenile fish.

    Lake Baroon, Photo by Tourism and Events Queensland.

    Lowland freshwater and intertidal and subtidal systems are well connected and provided important habitat for a range of migratory fishes, which need to move for breeding, food and other resources. These systems provide one of the most intact habitat mosaics in the sub-tropics. There are barriers to fish passage in some areas, particularly on the mainland and in developed areas.*** ^ Major impoundments include the Mary and Tinana barrages, which also define the upper tidal limit of those waterways, Teddington Weir, and Six Mile Creek (Lake McDonald),  Borumba and Baroon Pocket dams.

    Piped road crossing on tributary to the Mary River, Photo by Mary Chang.

    Teddington Weir, Photo by Department of Environment and Science, Queensland Government.

    The Strait itself is one of few sand passage estuaries in Australia. It supports extensive and diverse intertidal and subtidal systems, which provide valuable habitat for water mice, dugongs, Australian humpback dolphins, turtles, sea snakes, fishes, sharks, rays, crustaceans, many species of migratory shorebirds, whales as seasonal visitors, and other important species.

    Wetland type conceptual model - provided by Queensland Government.

    Red-capped plover, K'gari, Photo by Jenna Tapply, Queensland Government.

    Main image. Lake McKenzie, K'gari, Photo by Tourism and Events Queensland.

    *Areas mapped as ’contains wetlands’ typically include many small wetlands, which are too small to map individually.

    See links at the end of this map journals for further information on the following literature.

    **Australian Groundwater-Dependent Ecosystems Toolbox Part 1: Assessment Framework (Richardson et. al. 2011).

    ***Enhanced Management of Ramsar Site Wetlands within the Great Sandy Strait Catchments (Department of National Parks, Sports and Racing, 2016).

    ^Great Sandy Strait Biopassage Remediation Project – Final Report (Berghuis 2012).

    Great Sandy Ramsar site

    The Convention on Wetlands of International Importance (more commonly referred to as the Ramsar Convention) was adopted in 1971 in the Iranian city of Ramsar. The Convention aims to halt the worldwide loss of wetlands and to conserve remaining wetlands through wise use and management. The Ramsar Convention encourages the designation of sites containing representative, rare or unique wetlands, or wetlands that are important for conserving biological diversity.

    Queensland has five Ramsar sites: Currawinya Lakes, Shoalwater and Corio Bays Area, Great Sandy Strait, Moreton Bay and Bowling Green Bay. The Great Sandy Strait was listed as Ramsar site in 1999, and covers approximately 930 square kilometres.

    The Great Sandy Strait is particularly significant for its well-connected hydrology and its extensive near natural mosaic of freshwater, marine and estuarine habitats. At the interface of tropical and sub-tropical influences, it constitutes one of the most expansive, diverse and well-connected coastal wetland complexes along the entire east coast of Australia, including:

    • mangroves and saltmarshes,
    • seagrass meadows,
    • rare wetland types with large examples of patterned fens and freshwater peat wetlands,
    • fringing coral reefs, and
    • unusual coffee rock ecosystems including rocky shores and subtidal reefal gardens with soft corals and sponges.

    The Great Sandy Strait Ramsar site provides habitat for numerous wetland-dependent species including:

    • waterbirds including seasonally more than 20,000 birds with more than 260 bird species and more than 30 migratory species,
    • marine mammals including several whale and dolphin species,
    • marine reptiles including several turtle and sea snake species and the estuarine crocodile, and
    • fish, shark and invertebrate species at critical stages of their life cycles.

    Main image. Finger coral, Photo by Maria Zann.

    Great Sandy Biosphere

    The Great Sandy Biosphere* was designated by the United Nations Educational, Scientific and Cultural Organisation’s (UNESCO) Man and the Biosphere Program in 2009.**

    Boating, Photo by Tourism and Events Queensland.

    There are more than 680 biosphere reserves around the world. The Great Sandy is one of nine reserves in Australia, and one of two reserves in Queensland together with the adjacent Noosa Biosphere.***

    'Biosphere Reserves are sites that:

    • demonstrate innovative approaches to conservation and sustainable development
    • share their experience and ideas regionally, nationally and internationally within a world network of biosphere reserves, and
    • go beyond confined protected areas to where sustainable economic development is made possible through partnerships with its community.'***

    The Great Sandy Biosphere covers 1,416,000 hectares, including 542,000 hectares of marine ecosystems and 874,000 hectares of diverse landscape.

    The biosphere includes the:

    • ancient sand dunes
    • habitat for many many species of rare, threatened or endangered fauna and flora
    • rainforests growing on sand
    • perched lakes
    • World Heritage-listed Fraser Island
    • Great Sandy Strait Ramsar site
    • Great Sandy Marine Park, and
    • southern boundary of the GBR.**

    Main image. Tin Can Inlet looking towards Cooloola Cove (left) and Tin Can Bay (right), Photo by Gary Cranitch ©Queensland Museum.

    See links at the end of this map journal for further information on the following references.

    **Great Sandy Biosphere (Great Sandy Biosphere undated).

    **Noosa Biosphere (Noosa Biosphere Reserve Foundation 2019).

    Physical features—geology and topography

    Several different rock types combine to make up the geology of the surrounding catchments.

    Mapleton Falls, upper Mary catchment, Photo by Tourism and Events Queensland.

    The Mary and Susan catchments are dominated by hard geologies, mostly arenites, granitoids, mafites and felsites and ferricrete. Water rapidly runs off the older, harder and steeper arenite and granite. Some of the hard geologies are fractured (mafites and delsites) or weathered (ferricrete) and can allow for some local groundwater infiltration. There are areas of more porous geologies, such as alluvium, colluvium and basalt. These areas allow for water infiltration where not developed.

    K'gari is almost totally comprised of sand, with older Pleistocene (less than approx. 700,000 years ago) sand in the west and younger Holocene (less than approx. 10,000 years ago) sand in the east.* Water infiltrates through the sand, and relatively small areas of alluvium, supporting large groundwater systems and a wide range of GDEs such as perched lakes, palustrine wetlands (swamps), heaths and patterned fens. Felsite headlands on the east coast, are hard but fractures can allow for some local groundwater infiltration.

    Freshwater lake in the sand dunes, K'gari, Photo by Department of Environment and Science, Queensland Government.

    The mainland catchments are dominated by ferricrete and sedimentary rock. The ferricrete is formed by precipitation of iron and aluminium oxide nodules during water surface fluctuates within the geology during a long period of seasonal heavy rain (i.e. the Tertiary period, which includes the Cenozoic and Quaternary periods, approximately 66 million years ago to present day). These geologies are semi-permeable and can allow for some local groundwater infiltration. The sedimentary rock (Duckinwilla Group) is hard but geologically old (from the late Triassic to middle Jurassic, approximately 160 to 240 million years old) and can be deeply weathered with some local groundwater infiltration.

    Aquifers of the Maryborough Basin.**

    The lower parts of the mainland catchments are mostly porous, including alluvium, colluvium and sand. These areas allow for water infiltration where not developed. The southern sand dunes are part of the Cooloola sand mass, which extends to the Noosa River. The lower parts of the catchments are flat and prone to flooding, particularly where developed.

    Crab Creek, mainland catchments, Photo by Department of Environment and Science, Queensland Government.

    To the east of the Mary River are the sedimentary layers of the Maryborough Basin, which include the Elliott, Burrum Coal Measures, Grahams Creek, Duckinwilla and Maryborough formations. Most of these geologies are permeable to water (allow for aquifers), however the Maryborough Formation is hard (aquitards).

    Structural folding and deformation of the Maryborough Basin.**

    The Maryborough Basin has been folded and faulted (see red dashed lines in image above) and these different layers have been tilted and exposed to the surface in different areas across the basin.

    The Maryborough Basin under the sea.**

    Approximately one third of the Maryborough Basin is above sea level, with most of the basin underlying the Strait, western Hervey Bay and K'gari. The porous layers within the Maryborough Basin are likely to discharge groundwater into the sea (wonky holes***), and the large sand masses and other unconsolidated geologies also allow for extensive groundwater infiltration, storage and discharge. That is, the system surrounding the Strait has substantial groundwater influence from a range of porous geologies.

    Sandy beach sunrise, K'gari, Photo by Department of Environment and Science, Queensland Government.

    The Strait itself is dominated by unconsolidated sediments, mostly sand but also finer muds and coarser gravels derived from duricrusts. There are also areas of consolidated sediment, such as the low energy rocky shores of Round, Woody and Little Woody islands and the mainland, and rock bars in some of the coastal streams, and substrates of intermediate consolidation, such as coffee rock reefs and ledges.

    The Strait is mostly shallow (less than 10 metres) however there are several deeper areas. The deeper waters in the northern Strait are adjoining the tidal delta and Hervey Bay, in association with the Mary River paleochannel (i.e. the Mary River when sea levels were much lower). In the south, water flows through the broader Wide Bay Harbour and meets channels from Kauri Creek and the Tin Can Inlet. There is a deep hole in the Wide Bay Bar between the Inskip Peninsula and K'gari, which is where sand periodically falls into the sea.

    Video provided by Robbi Bishop-Taylor, Geoscience Australia, taken from Google Earth Engine. See links at the end of this map journal for further information.

    Conceptual models for several of the catchment's geology types are provided below.

    Fractured rocks - conceptual diagram by Queensland Government

    Exclusion zones - conceptual diagram by Queensland Government

    Alluvia - conceptual diagram by Queensland Government

    Alluvia - lower catchment - conceptual diagram by Queensland Government

    Beach ridges - conceptual diagram by Queensland Government

    Sand ridges - conceptual model by Queensland Government

    Main image. Gheerulla, Mapleton National Park, upper Mary River, Photo by Tourism and Events Queensland.

    See links at the end of this map journal for further information on the following references.

    *High resolution remapping of the coastal dune fields of south east Queensland, Australia: a morphometric approach (Patton et. al. 2019)

    **Regional Hydrogeological Characterisation of the Maryborough Basin, Queensland (Marshall et. al. 2015)

    Further Reading:

    1:250,000 Geological Series—Explanatory Notes. Fraser Island, Queensland (Grimes 1992)

    Geomorphology of the Inskip Peninsula, Queensland, Australia (Kohler and Shulmeister, 2019)

    ***Submarine groundwater discharge into the near-shore zone of the Great Barrier Reef, Australia (Stieglitz 2005)
    **A wonky hole is a type of submarine groundwater discharge (SGD). In the broader Great Barrier Reef region, four different types of SGD have been identified as listed below (Stieglitz 2005). This catchment story refers to wonky holes as type 3 and 4 SGDs.

    1. recirculation of seawater through animal burrows in mangrove
    2. forests
    3. freshwater SGD from unconfined aquifers as a narrow coastal fringe of freshwater along Wet Tropics beaches
    4. SGD from coastal dune systems in form of localised freshwater springs in the intertidal zone
    5. inner-shelf SGD from confined submarine aquifer systems comprised of riverine paleochannels incised into the shelf' (Stieglitz 2005).

    Physical features—rainfall

    The Wide Bay region usually experiences annual wet and dry seasons, with most of the rainfall typically between December and March*.

    Flooding, Photo by Penny Flaherty.

    Rainfall is important for some streams and waterbodies associated with the K'gari and Cooloola sand masses where there is more permanent groundwater flow. In other cases, such as the patterned fens, these are dependent on local rainfall to maintain soil moisture.

    In areas dominated by surface flow, such as the Mary River and mainland catchments, the hydrological seasonality associated with these wet and dry season flow conditions are important to the ecological character, function and associated values of aquatic ecosystems.

    Average annual rainfall** ranges from 751 to 2,001 millimetres per year. Rainfall is higher in the east and lower in the west due to orographic precipitation. As moist air moves over higher elevations, such as the large sand masses of K'gari and Cooloola, it rises and cools, forming orographic clouds mostly upwind of the mountain ridge. On the lee side of the sand masses (i.e. the north-west), rainfall is lower and the area is in a rain shadow. Very heavy precipitation typically occurs upwind of a prominent elevated features, such as a mountain range or sand mass, that is oriented across a prevailing wind from a warm ocean, as is the case on K'gari and the Cooloola sand mass.***

    Orographic precipitation conceptual model - provided by courtesy of Encyclopaedia Britannica, Inc., copyright 2012; used with permission.

    Main image. Obi Obi Creek, upper Mary catchment, Photo by Tourism and Events Queensland.

    *Climate Data Online (Bureau of Meteorology 2019) - see links at the end of this map journal for further information.

    **This dataset depicts the 50-year mean annual rainfall isohyets (contours) over Queensland for the period 1920 to 1969. The dataset was produced from the mean annual rainfall of as many locations as possible including private collections. Incomplete datasets were `made whole` by calculating values for missing periods through correlation with adjacent rainfall stations.

    ***Orographic Precipitation (Encyclopaedia Britannica 2019) - see links at the end of this map journal for further information.

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Last updated: 23 July 2020

This page should be cited as:

Department of Environment and Science, Queensland (2020) Great Sandy Strait catchment story – Overview, WetlandInfo website, accessed 24 September 2020. Available at:

Queensland Government
WetlandInfo   —   Department of Environment and Science