Transcript

Understanding how water flows in the catchment

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 focussed 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.

How to view this Map Journal

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Please note that the use of the terms 'Catchment' and 'Basin' are sometimes used interchangeably. In this Map Journal the term 'Catchment' has been used.

Main photo. Mangrove prop roots - provided by ©Queensland Government.

Map Journal for the Murray Catchment - water movement

This Map Journal describes the location, extent and values of the Murray Catchment. It demonstrates the key features which influence water flow, including geology, topography, rainfall and run-off, natural features, human modifications and land uses.

Knowing how water moves in the landscape is fundamental to sustainably managing the catchment and the services it provides.

Murray Catchment story

The Murray Catchment is in the Wet Tropics and part of the Wet Tropics World Heritage Area, and is around 1,115 km².

The area is managed by the Cassowary Coast Regional Council and the main township is Cardwell, which has a population of over 1,200 and is located on the coast.

The Tully and Herbert Catchments are located to the north, west and south of the Murray. Just off the coast to the east is Hinchinbrook Island, the largest island national park in Australia, and the catchment is adjacent to the world famous Great Barrier Reef.

The majority of the waterways in this catchment are short and steep due to the narrow topography. The Upper (North) Murray River joins the Murray River before flowing down the slopes into flatter agricultural land and into estuaries out into the Great Barrier Reef.

The other main rivers in the Murray Catchment are the Kennedy and Meunga creeks.

All these rivers form part of the broader Murray Catchment (click for animation).

Values of the catchment - environmental

The Murray Catchment provides significant environmental, economic and social values. It has high biodiversity and is home to some of Australia's most threatened species and ecological communities.

Cardwell is situated next to the Hinchinbrook Channel, a productive area for marine life, where dugong and sea turtles graze on seagrass.

The waters around Hinchinbrook Island are part of the Great Barrier Reef Marine Park and the island is protected within the Hinchinbrook Island National Park.

The Great Barrier Reef is one of the wonders of the natural world and is the world's largest coral reef ecosystem.

The broad leaf tea-tree (Melaleuca viridiflora) woodlands in high rainfall coastal north Queensland is an endangered ecological community (Regional Ecosystem 7.3.8). It is found in the catchment in several locations along the Bruce Highway.

Littoral Rainforest and Coastal Vine Thickets of Eastern Australia (Mixed Microphyll/Notophyll Vine Thicket on Beach Ridges) is a critically endangered ecological community in the Wet Tropics, and is located in small areas of the catchment along the coastal fringe.

The catchment is also home to important terrestrial values such as the mahogany glider (Petaurus gracilis) and the southern cassowary (Casuarius casuarius johnsonii).

Littoral rainforest and coastal vine thicket vegetation - provided by A. Ford, CSIRO

Values of the catchment - environmental and cultural

The Murray Catchment contains large areas of national parks and state forests, which include walking trails, 4WDing and camping. Rainforests in high elevations and waterfalls provide important recreational values for the community.

The Murray Catchment also falls within the Girringun Region Indigenous Protected Area (GIPA), which encompasses over 1.2 Million hectares of terrestrial, marine and coastal areas. The GIPA is comprised of mixed tenures and encompasses many layers of legislative and management responsibilities.

There are also several culturally important fish habitat areas - north in the Hull River and Tully River, then into the catchment at the Murray River, Dallachy, Wreck and Meunga Creek, and Hinchinbrook Island and Halifax.

Please note 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 protected areas.

Main photo. Murray Falls - provided by ©Queensland Government

Values of the catchment - economic and social

Other economic and social values of the area include agricultural and aquaculture production.

Due to the high natural values of the catchment, the land use is mainly conservation and natural environments. However, due to the highly productive flat alluvial plains, sugarcane, bananas, grazing on native pastures and other farming land uses are also present.

Fishing and aquaculture provide important economic and social values. The Hinchinbrook Channel provides sports fishing habitat, and there are many reefs close to shore which are easily accessible.

Natural features - geology and topography

The geology of the higher elevations of the Murray Catchment consist of steep granite formations, resistant to weathering that create high run-off ‘flashy’ areas with rapid flow.

The Upper Murray joins the Murray River near Warrami, where there is a constriction of hard impermeable rocks.

The remaining area is made up of permeable silts, sands and gravels and other materials deposited by rivers, called alluvium.

The geology of the lower coastal tidal flats, mangrove flats, supratidal flats, saltpans and grasslands consists of silt, mud and sand.

These different rock types combine to make up the geology of the Murray Catchment.

Natural features - rainfall

The Wet Tropics has the highest annual flow volume of any catchment within the Great Barrier Reef, with 33% of the flow from only 5% of the contributing land area.

The Murray Catchment is a high rainfall area, with between 1999 and 3201 mm per annum.

Natural features of the catchment - pre-clearing vegetation

Vegetation affects how water flows through the catchment, and this process is affected by land use and management practices. Native vegetation slows water, retaining it longer in the landscape and recharging groundwater aquifers, and reducing the erosion potential and the loss of soil from the catchment.

Historically, the vegetation* was melaleuca, eucalypt woodlands and forests, and rainforests and scrub.

Modified features - vegetation and land use

The main land use in the Murray Catchment is conservation and natural environments (64%). Other major land uses include sugar cane cropping in the north and grazing on native vegetation. Other major land uses include a range of forestry and horticulture (including bananas and mangoes), and small areas of residential development.

These different land use types combine to make up the land use of the Murray Catchment.

Modified features - vegetation clearing

Farming and residential development have resulted in some clearing, however large areas of remnant and regrowth vegetation remain in some areas.

Explore the Swipe Map using either of the options below.*

•Interactive Swipe App where you can zoom into areas and use the swipe bar (ESRI version)

•Interactive Swipe App where you can use the swipe bar. Use the white slide bar at the bottom of the map for a comparison (HTML version)

These developments and activities change the shape of the landscape and can modify water flow patterns.

* Depending on your internet browser, you may experience issues with one or the other. Please note this application takes time to load

Modified features - infrastructure

Buildings and important infrastructure such as roads, railways and creek crossings create impermeable surfaces and barriers that redirect water through single points or culverts, leading to channeling of water. This increases the rate of flow and the potential for erosion.

Modified features - dams and irrigation channels

Numerous channels, and some detention and retention basins, have been constructed in the alluvial areas in the Murray Catchment to manage drainage of the excess water from high rainfall, flood events and high groundwater tables. This is a highly modified floodplain system with a complex network of levees and drains that link off-stream lagoons and surface water features to manage the excess water.

This infrastructure has significantly altered water flows in terms of frequency, duration and volume. This, in turn, has impacted on the amount of sediments and nutrients entering the system.

Water flow

Water flows across the landscape into streams and eventually into the Murray River (click here to see the animation*). The remaining water either sinks into the ground where it supports a variety of terrestrial and groundwater dependent ecosystems or is used for other purposes.

The main rivers and creeks of the catchment start in the upper reaches on steeper slopes of harder granites and volcanics. They then flow towards the coast on a gradually deepening layer of alluvium. The north area of the catchment has wider alluvium floodplains. Whereas, south of Cardwell, the creeks are short and sharp, and flow from a steep range into the Hinchinbrook Channel.

The Tully Catchment influences the hydrology of the Murray Catchment, as some of the smaller tributaries drain into the Murray River from the Tully River. There is also hydrological connections with the Herbert Catchment through the Seymour River.

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How does the water flow in the catchment?

For general descriptive purposes, there are five broad areas;

A. Upper Murray River and surrounds (from headwaters to Warrami)

B. Middle Murray River and surrounds (from Warrami to Murrigal)

C. Lower Murray River and surrounds (from Murrigal to coast)

D. Meunga Creek and surrounds (including Cardwell)

E. Short run-off creeks south of Cardwell

A. Upper Murray River and surrounds (from headwaters to Warrami)

The upper parts of the Murray catchment at high elevation are incised, fast flowing and flashy creek systems on granites with limited alluvium. Waterfalls are a notable feature (e.g. Murray Falls). As elevation drops, alluvial development increases and there is more water recharge.

Where the Upper (North) Murray River joins the Murray (main) there is a constriction of hard impermeable rocks. Approaching Warrami, a gradually deepening layer of alluvium occurs.

At Warrami the major land uses are sugar cane cropping, grazing on native pastures, plantation and production forestry, horticulture (including bananas) and rural residential.

Upper Murray - photo provided by Jacqui Richards, Terrain NRM

B. Middle Murray River and surrounds (from Warrami to Murrigal)

The middle Murray flows north through an alluvial floodplain consisting of deep sandy clays. The alluvium contains aquifers that vary widely in terms of volume and transmissivity. Aquifers occur where there are paleochannels (underground rivers). Where clayish (fine grained) alluvium occurs, groundwater is hard to extract because the alluvium exhibits poor transmissivity. This also results in a more saturated landscape.

Constructed drains and channels support mixed cropping (sugar cane, fruit tree and watermelon plantations) on the western side of the Murray River. As the river flows east, the main land uses are sugar cane cropping, grazing on native pastures, plantation and production forestry, horticulture (including bananas) and rural residential.

The channel is well defined but breaks its banks in times of high flows. The floodplain is intersected by multiple road crossings, including the Bruce Highway, which has multiple culverts.

Agriculture in the middle Murray - provided by Jacqui Richards, Terrain NRM

C. Lower Murray River and surrounds (from Murrigal to coast)

The lower Murray River receives water from the surrounding alluvial aquifers and flows permanently.

East of the highway the alluvium consists of heavy dark clays with low transmissivity. The river is a braided, meandering, and slow flowing channel through this area except in times of flood.

Towards the coast there are many wetlands, including coastal and sub-coastal non-floodplain grass, sedge and herb swamps, tree swamps (palm) and floodplain tree swamps (melaleuca and eucalypt).

The Murray River then flows over extensive deposits of sand, which contain perched and window wetlands. At the mouth of the Murray River there is a large area of coastal rainforests and mangroves, this is part of Edmund Kennedy, Girramay National Park. It supports a vast diversity of flora and the highest diversity of fish in the Wet Tropics.

Mouth of the Murray River - provided by Jacqui Richards, Terrain NRM

D. Meunga Creek and surrounds (including Cardwell)

The major geologies were formed by a thin layer of lava flowing over granite, which stretched into a steep ridge along the coast from just south of Ellerbeck through to Macknade. There is a limited alluvial plain consisting of sandy clays.

The headwaters of Kennedy and Meunga creeks are located in steep slopes on a thin layer of lava over granite. Meunga Creek is an incised channel in volcanics, and well defined once it reaches alluvium. Limited groundwater is available in the alluvial aquifers.

Cardwell's water supply is from the headwaters of Meunga Creek. The main land uses are plantation and production forestry, rural residential, perennial horticulture, sugar cane cropping and grazing on native pastures.

The lowland areas have sandy substrates with good transmissivity allowing water to seep through.

E. Short run-off creeks south of Cardwell

The major geologies were formed by a thin layer of lava flowing over granite. There is a limited alluvial plain consisting of sandy clays along coast.
Water flows quickly off the hard geologies into the alluvium and drainage channels (north of Damper Creek) during the wet season. In the dry season there is little to no flow, but there are near permanent waterholes.

There is limited aquifer formation which restricts groundwater availability, but towards Rungoo, the alluvium deepens and acid sulfate soils are present.

The predominant land use includes grazing on native pastures, production and plantation forestry and aquaculture, as well as Port Hinchinbrook.

There are significant estuarine wetland developments all along the coastline.

Conclusion

The Murray Catchment shows how natural and modified features within the landscape impact on how water flows. These issues need to be managed to ensure that the significant natural (and social) values of the catchment are protected, and to minimise impacts on the multitude of values within the catchment and downstream in the Great Barrier Reef, while providing for residential, farming and other important land uses of the catchment.

Knowing how the catchment functions is also important for future planning, including climate resilience. With this knowledge, we can make better decisions about how we manage this vital area.

Main photo. The Upper Murray around Murray Falls - photo provided by Queensland Government.

Acknowledgements

Developed by the Queensland Wetlands Program in the Department of Environment and Science in partnership with:
Terrain NRM

Girringun Aboriginal Corporation

Cassowary Coast Regional Council

This resource should be cited as: Walking the Landscape – Murray Catchment Map Journal v1.0 (2016), presentation, Department of Environment and Science, Queensland.

Images provided by: Andrew Ford from CSIRO, Terrain NRM, and Queensland Government.

The Queensland Wetlands Program supports projects and activities that result in long-term benefits to the sustainable management, wise use and protection of wetlands in Queensland. The tools developed by the Program help wetlands landholders, managers and decision makers in government and industry.

Contact wetlands♲des.qld.gov.au or visit wetlandinfo.des.qld.gov.au

Disclaimer

This Map Journal has been prepared with all due diligence and care, based on the best available information at the time of publication. The department holds no responsibility for any errors or omissions within the document. Any decisions made by other parties based on this document are solely the responsibility of those parties. Information contained in this education module is from a number of sources and, as such, does not necessarily represent government or departmental policy.

Data sources, links and extra information

Acknowledgements

Developed by the Queensland Wetlands Program in the Department of Environment and Science in partnership with:

Terrain NRM

Girringun Aboriginal Corporation

Cassowary Coast Regional Council

This resource should be cited as: Walking the Landscape – Murray Catchment Map Journal v1.0 (2016), presentation, Department of Environment and Science, Queensland.

Images provided by: Andrew Ford from CSIRO, Terrain NRM, and Queensland Government.

The Queensland Wetlands Program supports projects and activities that result in long-term benefits to the sustainable management, wise use and protection of wetlands in Queensland. The tools developed by the Program help wetlands landholders, managers and decision makers in government and industry.

Contact wetlands♲des.qld.gov.au or visit wetlandinfo.des.qld.gov.au

Disclaimer

This Map Journal has been prepared with all due diligence and care, based on the best available information at the time of publication. The department holds no responsibility for any errors or omissions within the document. Any decisions made by other parties based on this document are solely the responsibility of those parties. Information contained in this education module is from a number of sources and, as such, does not necessarily represent government or departmental policy.

The Queensland Wetlands Program supports projects and activities that result in long-term benefits to the sustainable management, wise use and protection of wetlands in Queensland. The tools developed by the Program help wetlands landholders, managers and decision makers in government and industry.

Contact wetlands♲des.qld.gov.au or visit wetlandinfo.des.qld.gov.au

Data sources, links and information

Software Used

ArcGIS for Desktop | ArcGIS Online | Story Map Journal

Some of the information used to put together this Map Journal can be viewed on the QLD Globe.

The Queensland Globe is an interactive online tool that can be opened inside the Google Earth™ application. Queensland Globe allows you to view and explore Queensland spatial data and imagery. You can also download a cadastral SmartMap or purchase and download a current titles search.

More information about the layers used can be found here:

Source Data Table

Other References

Girringun Indigenous Protected Area Management Plan (2016) [webpage] Accessed 19 August 2016

Cassowary Coast Regional Council - flood mapping, studies and excavation maps

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Last updated: 25 August 2021