Infrastructure Engineering - Research Publications

Permanent URI for this collection

Search Results

Now showing 1 - 4 of 4
  • Item
    No Preview Available
    The time of emergence of climate-induced hydrologic change in Australian rivers
    John, A ; Nathan, R ; Horne, A ; Fowler, K ; Stewardson, M ; Peel, M ; Webb, JA (ELSEVIER, 2023-04)
  • Item
    Thumbnail Image
    Robust Climate Change Adaptation for Environmental Flows in the Goulburn River, Australia
    John, A ; Horne, A ; Nathan, R ; Fowler, K ; Webb, JA ; Stewardson, M (FRONTIERS MEDIA SA, 2021-12-06)
    Climate change presents severe risks for the implementation and success of environmental flows worldwide. Current environmental flow assessments tend to assume climate stationarity, so there is an urgent need for robust environmental flow programs that allow adaptation to changing flow regimes due to climate change. Designing and implementing robust environmental flow programs means ensuring environmental objectives are achieved under a range of uncertain, but plausible climate futures. We apply stress testing concepts previously adopted in water supply management to environmental flows at a catchment scale. We do this by exploring vulnerabilities in different river management metrics for current environmental flow arrangements in the Goulburn River, Australia, under non-stationary climatic conditions. Given the limitations of current environmental flows in supporting ecological outcomes under climate change, we tested three different adaptation options individually and in combination. Stress testing adaptation results showed that increasing environmental entitlements yielded the largest benefits in drier climate futures, whereas relaxing river capacity constraints (allowing more targeted delivery of environmental water) offered more benefits for current and wetter climates. Combining both these options led to greater than additive improvements in allocation reliability and reductions in environmental water shortfalls, and these improvements were achieved across a wider range of climatic conditions than possible with either of the individual options. However, adaptation may present additional risks to some ecological outcomes for wetter climates. Ultimately, there was a degree of plausible climate change beyond which none of the adaptation options considered were effective at improving ecological outcomes. This study demonstrates an important step for environmental flow assessments: evaluating the feasibility of environmental outcomes under climate change, and the intervention options that prove most robust under an uncertain future.
  • Item
    Thumbnail Image
    Climate change and freshwater ecology: Hydrological and ecological methods of comparable complexity are needed to predict risk
    John, A ; Horne, A ; Nathan, R ; Stewardson, M ; Webb, JA ; Wang, J ; Poff, NL (WILEY, 2021-03)
    Abstract Many freshwater ecosystems are in decline because of anthropogenic disturbance including climate change, yet our understanding of ecological vulnerability to future conditions including climatic variation is limited. Understanding climate risks to freshwater ecosystems requires combining hydrological and ecological knowledge. While there have been significant advances in ecohydrological approaches when applied within the large array of methods available for undertaking impact assessments, the ecological and hydrological elements are often not well‐integrated. This results in a mismatch in their ability to accommodate the inherent uncertainty in both impacts and responses. We examine published literature that assesses climate change impacts on freshwater ecosystems using both hydrological and ecological models to better understand method choices. We identify four fundamentally distinct modeling approaches used to assess climate change risk. We discuss which approaches are less useful for predicting ecological impacts under climate change, and highlight approaches of comparable complexity that can maximize the utility of dynamic, process‐based modeling while capturing the effects of climate uncertainty and variability. Using an illustrative case study of riparian vegetation health under climate change, we show how the four alternate modeling approaches feature different degrees of information in their outcomes and inferences about future risk. Most current studies that examine climate change risks to freshwater ecosystems use simplified methods or inadequately combine key elements. However, unless the interactions between changing hydrologic variability and ecological responses are explicitly captured in scale‐sensitive modeling methods, the risks of climate change to freshwater ecosystems will likely be substantially misrepresented, with negative consequences for effective management responses. Capturing these interactions requires combining ecological and hydrological methods of comparable complexity. This article is categorized under: Climate, Ecology, and Conservation > Modeling Species and Community Interactions
  • Item
    Thumbnail Image
    How to incorporate climate change into modelling environmental water outcomes: a review
    John, A ; Nathan, R ; Horne, A ; Stewardson, M ; Webb, JA (IWA Publishing, 2020-06-01)
    Environmental water represents a key resource in managing freshwater ecosystems against pervasive threats. The impacts of climate change add further pressures to environmental water management, yet anticipating these impacts through modelling approaches remains challenging due to the complexities of the climate, hydrological and ecological systems. In this paper, we review the challenges posed by each of these three areas. Large uncertainties in predicting climatic changes and non-stationarities in hydrological and ecological responses make anticipating impacts difficult. In addition, a legacy of relying on modelling approaches informed by historic dependencies in environmental water science may confound the prediction of ecological responses when extrapolating under novel conditions. We also discuss applying ecohydrological methods to support decision-making and review applications of bottom-up climate impact assessments (specifically eco-engineering decision scaling) to freshwater ecosystems. These approaches offer a promising way of incorporating climatic uncertainty and balancing competing environmental objectives, but some practical challenges remain in their adoption for modelling environmental water outcomes under climate change.