Identifying Functional Flow Linkages Between Stream Alteration and Biological Stream Condition Indices Across California

Large state or regional environmental flow programs, such as the one based on the California Environmental Flows Framework, rely on broadly applicable relationships between flow and ecology to inform management decisions. California, despite having high flow and bioassessment data density, has not established relationships between specific elements of the annual hydrograph and biological stream condition. To address this, we spatially and temporally linked USGS gage stations and biological assessment sites in California to identify suitable paired sites for comparisons of streamflow alteration with biological condition at a statewide scale. Flows were assessed using a set of functional flow metrics that provide a comprehensive way to compare alteration and seasonal variation in streamflow across different locations. Biological response was evaluated using the California Stream Condition Index (CSCI) and Algal Stream Condition Index (ASCI), which quantify biological conditions by translating benthic invertebrate or algal resources and watershed-scale environmental data into an overall measure of stream health. These indices provide a consistent statewide standard for interpreting bioassessment data, and thus, a means of quantitatively comparing stream conditions throughout the state. The results indicate that indices of biological stream condition were most closely associated with flow alteration in seasonality and timing metrics, such as fall pulse timing, dry-season timing, and wet season timing. Magnitude metrics such as dry-season baseflow, wet season baseflow, and the fall pulse magnitude were also important in influencing biological stream conditions. Development of ecological flow needs in large-scale environmental programs should consider that alteration to any of the seasonal flow components (e.g., dry-season baseflow, fall pulse flow, wet-season baseflow, spring recession flow) may be important in restructuring biological communities.

Eco-Factors for International Company Environmental Management Systems

Environmental management systems (EMS) require the assessment of environmental aspects to ensure that organizations recognize their most relevant impacts on the environment. The ecological scarcity method (ESM) provides weighting factors for environmental flows (pollutants and resources), called eco-factors (EF), applicable in the assessment of environmental aspects. EF are based on a distance-to-target approach, displaying the ratio of the current state to the respective policy targets for environmental flows. The ESM has been developed for Switzerland; however, for site-specific application beyond Switzerland, national EF are desirable. This publication presents a systematic procedure for the derivation of EF in an international framework, based on the investigation of eight countries worldwide and comprehensive data research. As a novel feature, the grouping of EF into sets is introduced, according to the character of the underlying policy target: legally based, intended policy, or expert recommendation. Overall, 134 EF for six environmental issues were calculated and applied in a case study from Volkswagen AG. An in-depth analysis identifies the differences between national EF and between sets of EF and discusses the implications for EMS. From the findings, general conclusions for future development and the application of EF in an international context of company management are derived.

The challenge of setting ‘climate ready’ ecological targets for environmental flow planning

Implementing environmental flows has emerged as a major restoration tool for addressing the impacts of hydrologic alteration in large river systems. The ‘natural flow paradigm’ has been a central guiding principle for determining important ecohydrological relationships. Yet, climate change and associated changes in rainfall run off relationships, seasonality of flows, disruptions to food webs and species life cycle cues mean these existing relationships will, in many circumstances, become obsolete. Revised thinking around setting ecological objectives is required to ensure restoration targets are achievable, particularly in regions where water scarcity is predicted to increase. Through this lens ‘climate ready’ targets are those that are robust to changing water availability or incorporate future adaptation options. Future objective setting should be based around the inclusion of changing climate and water availability, and the associated species and ecosystem vulnerabilities, and expected outcomes under different policy and adaptation options. This paper uses south eastern Australia as a case study region to review the extent to which current water management plans include climate considerations and adaptation in objective setting. Results show untested climate adaptation inclusions, and a general lack of acknowledgement of changing hydrological and ecological conditions in existing management plans. In response this paper presents a process for setting objectives so they can be considered ‘climate ready’.

Environmental Flows Assessments in the face of uncertainty: supporting the adaptive management of environmental flows

Adaptive management has become the preferred approach for managing environmental flows globally, and successful implementation recognizes multiple dimensions of variability and complexity in socio-ecological systems. This paper outlines an environmental flow assessment methodology that explicitly addresses the uncertainty and change inherent in adaptively managing multiple values for management of environmental flows. While non-stationarity and uncertainty are well recognised in the climate literature, these have not been addressed within the structure of environmental flows methodologies. Here, we present an environmental flow assessment that is structured to explicitly consider future change and uncertainty in climate and socio-ecological values, by examining scenarios using ecological models. The environmental flow assessment methodology further supports adaptive management through the intentional integration of participatory approaches and the inclusion of diverse stakeholders. We present a case study to demonstrate the feasibility of this approach, highlighting how this methodology facilitates adaptive management. Rethinking our approach to environmental flows assessments is an important step in ensuring that environmental flows continue to work effectively as a management tool under climate change.

Robust Climate Change Adaptation for Environmental Flows in the Goulburn River, Australia

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.