List of Titles

A legacy of climate and catchment change: the real challenge for wetland management

- Gell, Peter, Mills, Keely, Grundell, Rosie

Authors: Gell, Peter , Mills, Keely , Grundell, Rosie
Date: 2013
Type: Text , Journal article
Relation: Hydrobiologia Vol. 708, no. 1 (May 2013), p. 133-144
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Description: Wetland managers are faced with an array of challenges when restoring ecosystems at risk from changing climate and human impacts, especially as many of these processes have been operating over decadal-millennial timescales. Variations in the level and salinity of the large crater lakes of western Victoria, as revealed over millennia by the physical, chemical and biological evidence archived in sediments, attest to extended periods of positive rainfall balance and others of rainfall deficit. The recent declines in the depth of these lakes have been attributed to a 15% decline in effective rainfall since AD 1859. Whilst some sites reveal state shifts following past droughts, the response of most wetlands to millennial-scale climatic variations is muted. Regional wetland condition has changed comprehensively, however, since European settlement, on account of extensive catchment modifications. These modifications appear to have reduced the resilience of wetlands limiting their capacity to recover from the recent 'big dry'. These sedimentary archives reveal most modern wetlands to be outside their historical range of variability. This approach provides a longer-term context when assessing wetland condition and better establishes the restoration challenge posed by the impact of climate change and variability and human impacts.
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Development of hydraulic models for a complex and large scale water distribution system in regional Australia

- Mala-Jetmarova, Helena, Schwarz, S., Barton, Andrew, Le Roux, S, Smalley, P., Gerke, S.

Authors: Mala-Jetmarova, Helena , Schwarz, S. , Barton, Andrew , Le Roux, S , Smalley, P. , Gerke, S.
Date: 2011
Type: Text , Conference proceedings
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Description: Hydraulic simulation models have become a valuable tool to manage water distribution networks commencing from their initial design through their operation, assessment of the level of service to customers, system performance improvement, analysis of planning alternatives, to system optimisation. The development of hydraulic models can be a time consuming task with complex and large scale water distribution networks being particularly challenging. The Wimmera Mallee Pipeline (WMP) in Western Victoria, Australia is a recently constructed and unique regional scale water distribution system which consists of over 8,800 km of pressurised pipelines spreading across an area of approximately 20,000 km 2. Currently, the WMP provides water to 34 townships, rural farms and other water users across the Wimmera Mallee region with an annual design capacity of 31.6 mil. m 3. The WMP sources its water from multiple reservoirs in the Grampians mountain ranges in the south and the River Murray in the north. Grampians Wimmera Mallee Water (GWMWater) is the local water organisation responsible for managing the WMP. GWMWater is currently initiating the development of a water market to generate and support growth, and to ensure that water is available for the highest value social, economic or environmental use. The hydraulic models discussed in this paper will assure that informed decisions are made by GWMWater regarding the capacity to deliver water through the pipeline system, and therefore the extent of trade by customers. The philosophy for development of the WMP hydraulic models was to replicate the real system as credibly as possible into the level of required accuracy for decision making, yet enable simple model operation, maintenance and update. The network is modelled to the individual customer level in order to accommodate small diameter pipes. Modelling at this level simplifies the future model maintenance and updates, and also ensures the compatibility with other GWMWater's systems such as Geographic Information System (GIS) and the customer database. A major part of the model development consisted of data preparation. This was undertaken by using "as constructed" GIS asset data captured during the WMP construction and entered into a GIS database (ArcGIS by ESRI). Due to the scale of the system and associated amounts of data, it was essential to develop sophisticated data transformation and validation procedures to simplify the model build which thereby minimised manual data entry and potential sources of errors. This paper focuses on the methodologies and techniques used in data preparation for hydraulic models and development of hydraulic models. An example is also provided of how the models will be used as a decision support tool in water supply and allocation planning.

Implications of environmental trajectories for limits of acceptable change : A case study of the Riverland Ramsar site, South Australia

- Newall, Peter, Lloyd, Lance, Gell, Peter, Walker, Keith

Authors: Newall, Peter , Lloyd, Lance , Gell, Peter , Walker, Keith
Date: 2016
Type: Text , Journal article
Relation: Marine and Freshwater Research Vol. 67, no. 6 (2016), p. 738-747
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Description: The Riverland Ramsar site in south-eastern Australia has Limits of Acceptable Change (LAC) derived on the basis of hydrological regimes and vegetation requirements. This study evaluated LAC for the site against trajectories of environmental change including increasing river regulation and changing climate. The study identified a high likelihood of exceedances of the LAC from changed hydrologic regime and also from changing climate, with the combined influences increasing the likelihood of breaches. Regional climatic variations in the past call into question the concept of baseline conditions for this site and elsewhere, and suggest that management plans based on ecological variation around a point in time will be insufficient. Vulnerability assessment, adaptation enhancement, and regular reviews of site condition and regional significance are suggested components for future management of Ramsar sites. Journal compilation © CSIRO 2016.

Hydrological change in the Coorong Estuary, Australia, past and present : Evidence from fossil invertebrate and algal assemblages

- Reeves, Jessica, Haynes, Deborah, Garcia, Adriana, Gell, Peter

Authors: Reeves, Jessica , Haynes, Deborah , Garcia, Adriana , Gell, Peter
Date: 2015
Type: Text , Journal article
Relation: Estuaries and Coasts Vol. 38, no. 6 (2015), p. 2101-2116
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Description: Estuaries are defined by change; both on a diurnal basis, balancing tidal inflow with riverine outflow, and over hundreds or thousands of years through geomorphic evolution and sea level variability. However, contemporary management and protection underpinned by international agreements, such as the Ramsar Convention, presume that wetlands change within only limited ranges based on their contemporary conditions. Adaptive management strategies for cyclic or even directional change are more robust if underpinned by evidence from longer-term records, such as those obtained from palaeoecological records preserved in sediment cores. Such is the case for the Coorong lagoon in southern Australia; here analysisÂ of assemblage changes of key invertebrates and algae preserved in the sediments reveals the variability of natural conditions well before the instrumental record. During the mid-Holocene to late Holocene and up until the mid-twentieth century, assemblage changes in microfauna and flora indicate variable salinity and water clarity associated with both fresh continental and marine water inputs. By contrast, in the south lagoon, the proxies indicate periodically enhanced salinity. The most significant changes in ecology and sedimentation are apparent after the 1950s; hydrological modifications have changed the influence of both continental and tidal water, producing conditions that are unusual in the long-term history of the site. © 2014, Coastal and Estuarine Research Federation.

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Resilience in a aquatic ecosystems : Developing predictive models to explain the effects of anthropogenic stressors on Murray-Darling Basin billabongs

- Reid, Michael, Gell, Peter, Davidson, Thomas, Sayer, Carl, Tibby, John, Fluin, Jennie

Authors: Reid, Michael , Gell, Peter , Davidson, Thomas , Sayer, Carl , Tibby, John , Fluin, Jennie
Date: 2014
Type: Text , Conference paper
Relation: Symposium on Australia-China Wetland Network Research Partnership; Nanjing Institute of Geography and Limnology Chinese Academy of Sciences (NIGLAS) Nanjing, China; 23rd-28th December 2014 p. 61-67
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Description: Freshwater ecosystems are among the most threatened in the world (MEA 2005) and have been identified as one of the ten Australian ecosystems most vulnerable to tipping points. The floodplain lakes and wetlands (billabongs) of the Murray-Darling Basin (MDB) are hotspots of productivity and diversity and provide important breeding, feeding and refuge habitat for a range of floodplain river biota, as well as important ecosystem goods and services by way of flood mitigation, nutrient cycling and sediment trapping. Nonetheless, MDB billabongs are threatened by water resource and agricultural development and climate change. In recognition of these threats, water dependent ecosystems of the MDB are currently subject to expensive and controversial management measures involving water buy backs estimated to cost up to $30 billion and the subsequent delivery of environmental water. The need to understand the critical drivers of change and the internal system interactions that underlie ecosystem responses in floodplain river ecosystems has never been greater. This project will develop ecosystem response models that will not only identify the critical threatening drivers, but also provide the guidance necessary to rehabilitate these important ecosystems.

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Cladoceran-inferred ecological and hydrological changes of two floodplain wetlands in two large river systems, the Murray (Australia) and Yangtze Rivers (China)

- Kattel, Giri, Dong, Xuhui, Yang, Xiangdong

Authors: Kattel, Giri , Dong, Xuhui , Yang, Xiangdong
Date: 2014
Type: Text , Conference paper
Relation: Symposium on Australia-China Wetland Network Research Partnership; Nanjing Institute of Geography and Limnology Chinese Academy of Sciences (NIGLAS) Nanjing, China; 23rd-28th December 2014 p. 42-49
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Description: The landscapes of two of the world’s large river basins, the Murray and Yangtze Rivers of Australia and China, have been intensively developed for the provision of food and water resources. Long term archives of change, reveal that man-made infrastructures in the river and catchment modifications for agricultural and industrial developments have reduced the resilience of wetlands ecosystem structure and functions in recent decades. The river regulations imposed during the 20th centuries in the Murray and Yangtze Rivers have transformed hydrology and ecology of the river and associated wetlands. High resolution, subfossil cladoceran assemblages retrieved from Kings Billabong and Zhangdu Lake of the Murray and Yangtze Rivers, have strongly responded to human disturbances in the past. Ratios of littoral to planktonic (L:P) assemblages of subfossil cladocerans and the number of ephippial remains in Kings Billabong indicated the shift in hydrology and ecology of Kings Billabong, and ecological stress as a result of changes in naturally occurring dry-wet cycles following river regulation (1927 AD). Similarly, the subfossil cladoceran assemblages and their ephippia in Zhangdu Lake also reflected the impacts of the construction of the Three Gorges Dam (1954) in the Yangtze River on hydrology and ecology of the wetland.

Palaeoecological evidence for sustained change in a shallow Murray River (Australia) floodplain lake: regime shift or press response?

- Kattel, Giri, Gell, Peter, Zawadzki, Atun, Barry, Linda

Authors: Kattel, Giri , Gell, Peter , Zawadzki, Atun , Barry, Linda
Date: 2017
Type: Text , Journal article
Relation: Hydrobiologia Vol. 787, no. 1 (2017), p. 269-290
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Description: Paleolimnological techniques can reveal long-term perturbations and associated stable state transitions of lake ecosystems. However, such transitions are difficult to predict since changes to lake ecosystems can be abrupt or gradual. This study examined whether there were past transitions in the ecological regime of Kings Billabong, a shallow River Murray wetland in southeast Australia. A 94-cm-long core, covering c. 90 years of age, was analysed at 1 cm resolution for subfossil cladocerans, diatoms and other proxies. Prior to river regulation (c. 1930), the littoral to planktonic ratios of cladocerans and diatoms, and bulk sediment delta C-13 values were high, while the period from c. 1930 to c. 1970 experienced considerable changes to the wetland ecosystem. The abrupt nature of changes of planktonic cladocerans and diatoms, particularly after the onset of river regulation (1930s), was triggered by inundation, high rates of sedimentation and shifts in bulk sediment delta N-15 values. However, the transition of a once littoral-dominated community, to one favouring an increasingly turbid, plankton-dominated trophic condition following river regulation was relatively slow and lasted for decades. The progression to a new regime was likely delayed by the partial recovery of submerged plant communities and related internal dynamics.

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