Linking water-resource models to ecosystem-response models to guide water-resource planning - an example from the Murray - Darling Basin, Australia

2011 ◽  
Vol 62 (3) ◽  
pp. 279 ◽  
Author(s):  
Rebecca E. Lester ◽  
Ian T. Webster ◽  
Peter G. Fairweather ◽  
William J. Young

Objectively assessing ecological benefits of competing watering strategies is difficult. We present a framework of coupled models to compare scenarios, using the Coorong, the estuary for the Murray–Darling River system in South Australia, as a case study. The framework links outputs from recent modelling of the effects of climate change on water availability across the Murray–Darling Basin to a hydrodynamic model for the Coorong, and then an ecosystem-response model. The approach has significant advantages, including the following: (1) evaluating management actions is straightforward because of relatively tight coupling between impacts on hydrology and ecology; (2) scenarios of 111 years reveal the impacts of realistic climatic and flow variability on Coorong ecology; and (3) ecological impact is represented in the model by a series of ecosystem states, integrating across many organisms, not just iconic species. We applied the approach to four flow scenarios, comparing conditions without development, current water-use levels, and two predicted future climate scenarios. Simulation produced a range of hydrodynamic conditions and consequent distributions of ecosystem states, allowing managers to compare scenarios. This approach could be used with many climates and/or management actions for optimisation of flow delivery to environmental assets.

2020 ◽  
Vol 71 (8) ◽  
pp. 1040
Author(s):  
Mat Gilfedder ◽  
Geoff Podger ◽  
David W. Rassam ◽  
Dan Pagendam ◽  
Catherine J. Robinson

The application of river-system models to inform water-resource planning and management is a growing global phenomenon. This requires models to be applied so that they are useful to water decision makers charged with setting targets that provide adequate water flows to sustain landholders and communities. This article examines why and how the innovative application of river-system models can facilitate interactions between water science and water management in Australia's Murray–Darling Basin (the Basin). A trajectory river-modelling method was applied to run multiple short historical climate sequences through a river-system model to provide historical probabilities. These can allow better assessment of the risks and impacts associated with stream flow and water availability. This method allows known historical variability to be presented, and produces relevant results for a 10–15-year water-sharing plan lifetime. The benefits were demonstrated in the Basin's Lachlan Catchment where modelled river-flow results demonstrated the increased variability between shorter 15-year sequences than for a single 114-year run. This approach highlighted the benefits of expressing modelling results as historical probabilities to inform short-term and strategic water-planning efforts.


2014 ◽  
Vol 65 (12) ◽  
pp. 1072 ◽  
Author(s):  
Mat Gilfedder ◽  
Geoff Podger ◽  
David W. Rassam ◽  
Dan Pagendam ◽  
Catherine J. Robinson

The application of river-system models to inform water-resource planning and management is a growing global phenomenon. This requires models to be applied so that they are useful to water decision makers charged with setting targets that provide adequate water flows to sustain landholders and communities. This article examines why and how the innovative application of river-system models can facilitate interactions between water science and water management in Australia’s Murray–Darling Basin (the Basin). A trajectory river-modelling method was applied to run multiple short historical climate sequences through a river-system model to provide historical probabilities. These can allow better assessment of the risks and impacts associated with stream flow and water availability. This method allows known historical variability to be presented, and produces relevant results for a 10–15-year water-sharing plan lifetime. The benefits were demonstrated in the Basin’s Lachlan Catchment where modelled river-flow results demonstrated the increased variability between shorter 15-year sequences than for a single 114-year run. This approach highlighted the benefits of expressing modelling results as historical probabilities to inform short-term and strategic water-planning efforts.


Author(s):  
G. M. Podger ◽  
S. M. Cuddy ◽  
L. Peeters ◽  
T. Smith ◽  
R. H. Bark ◽  
...  

Abstract. Water jurisdictions in Australia are required to prepare and implement water resource plans. In developing these plans the common goal is realising the best possible use of the water resources – maximising outcomes while minimising negative impacts. This requires managing the risks associated with assessing and balancing cultural, industrial, agricultural, social and environmental demands for water within a competitive and resource-limited environment. Recognising this, conformance to international risk management principles (ISO 31000:2009) have been embedded within the Murray-Darling Basin Plan. Yet, to date, there has been little strategic investment by water jurisdictions in bridging the gap between principle and practice. The ISO 31000 principles and the risk management framework that embodies them align well with an adaptive management paradigm within which to conduct water resource planning. They also provide an integrative framework for the development of workflows that link risk analysis with risk evaluation and mitigation (adaptation) scenarios, providing a transparent, repeatable and robust platform. This study, through a demonstration use case and a series of workflows, demonstrates to policy makers how these principles can be used to support the development of the next generation of water sharing plans in 2019. The workflows consider the uncertainty associated with climate and flow inputs, and model parameters on irrigation and hydropower production, meeting environmental flow objectives and recreational use of the water resource. The results provide insights to the risks associated with meeting a range of different objectives.


2021 ◽  
pp. 1-12
Author(s):  
Matthias Moros ◽  
Patrick De Deckker ◽  
Kerstin Perner ◽  
Ulysses S. Ninnemann ◽  
Lukas Wacker ◽  
...  

Abstract Northern and southern hemispheric influences—particularly changes in Southern Hemisphere westerly winds (SSW) and Southern Ocean ventilation—triggered the stepwise atmospheric CO2 increase that accompanied the last deglaciation. One approach for gaining potential insights into past changes in SWW/CO2 upwelling is to reconstruct the positions of the northern oceanic fronts associated with the Antarctic Circumpolar Current. Using two deep-sea cores located ~600 km apart off the southern coast of Australia, we detail oceanic changes from ~23 to 6 ka using foraminifer faunal and biomarker alkenone records. Our results indicate a tight coupling between hydrographic and related frontal displacements offshore South Australia (and by analogy, possibly the entire Southern Ocean) and Northern Hemisphere (NH) climate that may help confirm previous hypotheses that the westerlies play a critical role in modulating CO2 uptake and release from the Southern Ocean on millennial and potentially even centennial timescales. The intensity and extent of the northward displacements of the Subtropical Front following well-known NH cold events seem to decrease with progressing NH ice sheet deglaciation and parallel a weakening NH temperature response and amplitude of Intertropical Convergence Zone shifts. In addition, an exceptional poleward shift of Southern Hemisphere fronts occurs during the NH Heinrich Stadial 1. This event was likely facilitated by the NH ice maximum and acted as a coup-de-grâce for glacial ocean stratification and its high CO2 capacitance. Thus, through its influence on the global atmosphere and on ocean mixing, “excessive” NH glaciation could have triggered its own demise by facilitating the destratification of the glacial ocean CO2 state.


2013 ◽  
Vol 64 (10) ◽  
pp. 932 ◽  
Author(s):  
L. B. Bucater ◽  
J. P. Livore ◽  
C. J. Noell ◽  
Q. Ye

Estuaries are transition zones that link freshwater and marine ecosystems and are often used as nursery areas by fish. The Murray–Darling Basin, which is heavily affected by flow regulation and water extraction, is the largest river system in Australia and terminates at the Murray Mouth estuary. Protracted drought conditions resulted in extremely low flows to the Murray Mouth that affected water condition, fish abundance, community structure and fish use of the estuary (e.g. nursery areas). The aims of the present study were to examine temporal changes in larval fish assemblages in this estuary. The assemblages were dominated by two gobiid species, Arenigobius bifrenatus and Tasmanogobius lasti. There was a noticeable absence or low abundance of freshwater, diadramous and large-bodied marine species that use this estuary for reproductive functions. Monthly differences in larval fish assemblages, between August–September and October–November, were attributed to increases in the abundances of A. bifrenatus in October and November and oscillation in T. lasti during the entire sampling period. The outcomes of the present study suggested that larval fish assemblages in drought conditions are limited to small-bodied species tolerant of high salinities and that freshwater flows are needed for the estuary to function as a nursery for other species.


2016 ◽  
Vol 20 (5) ◽  
pp. 1869-1884 ◽  
Author(s):  
Claire L. Walsh ◽  
Stephen Blenkinsop ◽  
Hayley J. Fowler ◽  
Aidan Burton ◽  
Richard J. Dawson ◽  
...  

Abstract. Globally, water resources management faces significant challenges from changing climate and growing populations. At local scales, the information provided by climate models is insufficient to support the water sector in making future adaptation decisions. Furthermore, projections of change in local water resources are wrought with uncertainties surrounding natural variability, future greenhouse gas emissions, model structure, population growth, and water consumption habits. To analyse the magnitude of these uncertainties, and their implications for local-scale water resource planning, we present a top-down approach for testing climate change adaptation options using probabilistic climate scenarios and demand projections. An integrated modelling framework is developed which implements a new, gridded spatial weather generator, coupled with a rainfall-runoff model and water resource management simulation model. We use this to provide projections of the number of days and associated uncertainty that will require implementation of demand saving measures such as hose pipe bans and drought orders. Results, which are demonstrated for the Thames Basin, UK, indicate existing water supplies are sensitive to a changing climate and an increasing population, and that the frequency of severe demand saving measures are projected to increase. Considering both climate projections and population growth, the median number of drought order occurrences may increase 5-fold by the 2050s. The effectiveness of a range of demand management and supply options have been tested and shown to provide significant benefits in terms of reducing the number of demand saving days. A decrease in per capita demand of 3.75 % reduces the median frequency of drought order measures by 50 % by the 2020s. We found that increased supply arising from various adaptation options may compensate for increasingly variable flows; however, without reductions in overall demand for water resources such options will be insufficient on their own to adapt to uncertainties in the projected changes in climate and population. For example, a 30 % reduction in overall demand by 2050 has a greater impact on reducing the frequency of drought orders than any of the individual or combinations of supply options; hence, a portfolio of measures is required.


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