Applying and Assessing Participatory Approaches in an Environmental Flows Case Study.

Environmental flows (e-flows) management takes place within a complex social-ecological system, necessitating the involvement of diverse stakeholders and an appreciation of a range of perspectives and knowledge types. It is widely accepted that incorporating participatory methods into environmental flows decision-making will allow stakeholders to become meaningfully involved, improving potential solutions, and fostering social legitimacy. However, due to substantial structural barriers, implementing participatory approaches can be difficult for water managers. This paper assesses the effectiveness of an e-flows methodology that combines elements of structured decision-making and participatory modeling, whilst constrained by project resources. Three process-based objectives were identified by the group at the start of the process: improving transparency, knowledge exchange, and community ownership. We evaluated the success of the approach according to those objectives using semi-structured interviews and thematic analysis. In evaluating how well the participatory approach achieved the process objectives, we found that at least 80% of respondents expressed positive sentiment in every category (n = 15). We demonstrate that the values-based process objectives defined by the participant group are an effective tool for evaluating participatory success. This paper highlights that participatory approaches can be effective even in resource-constrained environments when the process is adapted to fit the decision-making context.

A multi-model approach to assessing the impacts of catchment characteristics on spatial water quality in the Great Barrier Reef catchments.

Water quality monitoring programs often collect large amounts of data with limited attention given to the assessment of the dominant drivers of spatial and temporal water quality variations at the catchment scale. This study uses a multi-model approach: a) to identify the influential catchment characteristics affecting spatial variability in water quality; and b) to predict spatial variability in water quality more reliably and robustly. Tropical catchments in the Great Barrier Reef (GBR) area, Australia, were used as a case study. We developed statistical models using 58 catchment characteristics to predict the spatial variability in water quality in 32 GBR catchments. An exhaustive search method coupled with multi-model inference approaches were used to identify important catchment characteristics and predict the spatial variation in water quality across catchments. Bootstrapping and cross-validation approaches were used to assess the uncertainty in identified important factors and robustness of multi-model structure, respectively. The results indicate that water quality variables were generally most influenced by the natural characteristics of catchments (e.g., soil type and annual rainfall), while anthropogenic characteristics (i.e., land use) also showed significant influence on dissolved nutrient species (e.g., NOX, NH4 and FRP). The multi-model structures developed in this work were able to predict average event-mean concentration well, with Nash-Sutcliffe coefficient ranging from 0.68 to 0.96. This work provides data-driven evidence for catchment managers, which can help them develop effective water quality management strategies.

Evaluating the Ecological Benefits of Management Actions to Complement Environmental Flows in River Systems.

Globally, many river systems are under stress due to overconsumption of water. Governments have responded with programmes to deliver environmental water to improve environmental outcomes. Although such programmes are essential, they may not be sufficient to achieve all desired environmental outcomes. The benefits of environmental water allocation may be improved using 'complementary measures', which are non-flow-based actions, such as infrastructure works, vegetation management and pest control. The value of complementary measures is recognised globally, but their ecological benefits are rarely well understood, either because there is limited experience with their application, or the importance of context- and location-specific factors make it difficult to generalise benefits. In this study, we developed an approach to evaluate complementary measures at different levels of detail as a mechanism to aid decision-making. For systems that require a rapid, high-level evaluation, we propose a score-based multi-criteria benefit assessment module. If more ecological detail is necessary, we outline a method based on conceptual models, expert elicitation and probability assessment. These results are used to populate a cumulative benefit assessment tool. The tool evaluates the benefits of proposed measures in the wider context by including variables such as flow, dependence on ongoing maintenance and additional ecological values. We illustrate our approach through application to the Murray-Darling Basin, Australia. As many water recovery programmes mature into their evaluation phases, there is an increasing need to evaluate the ecological benefits of including complementary measures in the toolkit available to policy makers.

A simulation-based approach to assess the power of trend detection in high- and low-frequency water quality records.

To provide more precise understanding of water quality changes, continuous sampling is being used more in surface water quality monitoring networks. However, it remains unclear how much improvement continuous monitoring provides over spot sampling, in identifying water quality changes over time. This study aims (1) to assess our ability to detect trends using water quality data of both high and low frequencies and (2) to assess the value of using high-frequency data as a surrogate to help detect trends in other constituents. Statistical regression models were used to identify temporal trends and then to assess the trend detection power of high-frequency (15 min) and low-frequency (monthly) data for turbidity and electrical conductivity (EC) data collected across Victoria, Australia. In addition, we developed surrogate models to simulate five sediment and nutrients constituents from runoff, turbidity and EC. A simulation-based statistical approach was then used to the compare the power to detect trends between the low- and high-frequency water quality records. Results show that high-frequency sampling shows clear benefits in trend detection power for turbidity, EC, as well as simulated sediment and nutrients, especially over short data periods. For detecting a 1% annual trend with 5 years of data, up to 97% and 94% improvements on the trend detection probability are offered by high-frequency data compared with monthly data, for turbidity and EC, respectively. Our results highlight the benefits of upgrading monitoring networks with wider application of high-frequency sampling.

Adaptive Management of Environmental Flows.

Adaptive management enables managers to work with complexity and uncertainty, and to respond to changing biophysical and social conditions. Amid considerable uncertainty over the benefits of environmental flows, governments are embracing adaptive management as a means to inform decision making. This Special Issue of Environmental Management presents examples of adaptive management of environmental flows and addresses claims that there are few examples of its successful implementation. It arose from a session at the 11th International Symposium on Ecohydraulics held in Australia, and is consequently dominated by papers from Australia. We classified the papers according to the involvement of researchers, managers and the local community in adaptive management. Five papers report on approaches developed by researchers, and one paper on a community-led program; these case studies currently have little impact on decision making. Six papers provide examples involving water managers and researchers, and two papers provide examples involving water managers and the local community. There are no papers where researchers, managers and local communities all contribute equally to adaptive management. Successful adaptive management of environmental flows occurs more often than is perceived. The final paper explores why successes are rarely reported, suggesting a lack of emphasis on reflection on management practices. One major challenge is to increase the documentation of successful adaptive management, so that benefits of learning extend beyond the project where it takes place. Finally, moving towards greater involvement of all stakeholders is critical if we are to realize the benefits of adaptive management for improving outcomes from environmental flows.

Make the Most of the Data You've Got: Bayesian Models and a Surrogate Species Approach to Assessing Benefits of Upstream Migration Flows for the Endangered Australian Grayling.

Environmental water managers must make best use of allocations, and adaptive management is one means of improving effectiveness of environmental water delivery. Adaptive management relies on generation of new knowledge from monitoring and evaluation, but it is often difficult to make clear inferences from available monitoring data. Alternative approaches to assessment of flow benefits may offer an improved pathway to adaptive management. We developed Bayesian statistical models to inform adaptive management of the threatened Australian grayling (Prototroctes maraena) in the coastal Thomson River, South-East Victoria Australia. The models assessed the importance of flows in spring and early summer (migration flows) for upstream dispersal and colonization of juveniles of this diadromous species. However, Australian grayling young-of-year were recorded in low numbers, and models provided no indication of the benefit of migration flows. To overcome this limitation, we applied the same models to young-of-year of a surrogate species (tupong-Pseudaphritis urvilli)-a more common diadromous species expected to respond to flow similarly to Australian grayling-and found strong positive responses to migration flows. Our results suggest two complementary approaches to supporting adaptive management of Australian grayling. First, refine monitoring approaches to allow direct measurement of effects of migration flows, a process currently under way. Second, while waiting for improved data, further investigate the use of tupong as a surrogate species. More generally, alternative approaches to assessment can improve knowledge to inform adaptive management, and this can occur while monitoring is being revised to directly target environmental responses of interest.

River Bank Erosion and the Influence of Environmental Flow Management.

Environmental flows aim to influence river hydrology to provide appropriate physical conditions for ecological functioning within the restrictions of flow regulation. The hydrologic characteristics of flow events, however, may also lead to unintended morphologic effects in rivers, such as increases in riverbank erosion beyond natural rates. This may negatively impact habitat for biota, riparian infrastructure, and land use. Strategic environmental flow delivery linked to monitoring and adaptive management can help mitigate risks. We monitor riverbank condition (erosion and deposition) relative to environmental flows on the Goulburn River, Victoria, Australia. We describe the process of adaptive management aimed at reducing potential impacts of flow management on bank condition. Field measurements (erosion pins) quantify the hydrogeomorphic response of banks to the delivery of planned and natural flow events. Managed flows provide opportunities for monitoring riverbank response to flows, which in turn informs planning. The results demonstrate that environmental flows have little influence on bank erosion and visual perceptions in the absence of monitoring are an unreliable guide. This monitoring project represents a mutually beneficial, science-practice partnership demonstrating that a traditional 'know then do' approach can be foreshortened by close collaboration between researchers and managers. To do so requires transparent, often informal lines of communication. The benefits for researchers-a more strategic and targeted approach to monitoring activities; and benefits for the practitioners-reduced time between actions and understanding response; mean that a learn by doing approach is likely to have better outcomes for researchers, stakeholders, the public, and the environment.

Informing Environmental Water Management Decisions: Using Conditional Probability Networks to Address the Information Needs of Planning and Implementation Cycles.

One important aspect of adaptive management is the clear and transparent documentation of hypotheses, together with the use of predictive models (complete with any assumptions) to test those hypotheses. Documentation of such models can improve the ability to learn from management decisions and supports dialog between stakeholders. A key challenge is how best to represent the existing scientific knowledge to support decision-making. Such challenges are currently emerging in the field of environmental water management in Australia, where managers are required to prioritize the delivery of environmental water on an annual basis, using a transparent and evidence-based decision framework. We argue that the development of models of ecological responses to environmental water use needs to support both the planning and implementation cycles of adaptive management. Here we demonstrate an approach based on the use of Conditional Probability Networks to translate existing ecological knowledge into quantitative models that include temporal dynamics to support adaptive environmental flow management. It equally extends to other applications where knowledge is incomplete, but decisions must still be made.

The potential for dams to impact lowland meandering river floodplain geomorphology.

The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an "environmental sediment regime" to operate alongside environmental flows.

Environmental flows can reduce the encroachment of terrestrial vegetation into river channels: a systematic literature review.

Encroachment of riparian vegetation into regulated river channels exerts control over fluvial processes, channel morphology, and aquatic ecology. Reducing encroachment of terrestrial vegetation is an oft-cited objective of environmental flow recommendations, but there has been no systematic assessment of the evidence for and against the widely-accepted cause-and-effect mechanisms involved. We systematically reviewed the literature to test whether environmental flows can reduce the encroachment of terrestrial vegetation into river channels. We quantified the level of support for five explicit cause-effect hypotheses drawn from a conceptual model of the effects of flow on vegetation. We found that greater inundation, variously expressed as changes in the area, depth, duration, frequency, seasonality, and volume of surface water, generally reduces riparian vegetation abundance in channels, but most studies did not investigate the specific mechanisms causing these changes. Those that did show that increased inundation results in increased mortality, but also increased germination. The evidence was insufficient to determine whether increased inundation decreases reproduction. Our results contribute to hydro-ecological understanding by using the published literature to test for general cause-effect relationships between flow regime and terrestrial vegetation encroachment. Reviews of this nature provide robust support for flow management, and are more defensible than expert judgement-based approaches. Overall, we predict that restoration of more natural flow regimes will reduce encroachment of terrestrial vegetation into regulated river channels, partly through increased mortality. Conversely, infrequent deliveries of environmental flows may actually increase germination and subsequent encroachment.

Pulse disturbances to the colonization of hard-substrates and in situ determination of copper using diffusive gradients in thin-films (DGT): quantifying dose and response in the field.

Studies conducted in Port Philip Bay, Victoria, Australia are described that examined the effect of experimentally elevated copper concentrations on the recruitment of epifauna to settlement plates. Simultaneous measurement of the copper concentration using diffusive gradients in thin films (DGT) allowed direct comparisons to be made between the labile copper concentration measured at the settlement surface, and the biological effects observed. Copper concentrations created by the field dosing technique were between 20-30 micrograms l-1 for the first 2 d, but then dropped considerably for the following 4 d (3 micrograms l-1), and were indistinguishable from background for the final 7 d. The first 2 d of a copper pulse reduced the recruitment of barnacles, ascidians, serpulid worms, an encrusting bryozoan, and didemnid ascidians. The impacts occurred despite the copper pulse being much less than published LC50 values for similar species. The impacts were no longer obvious by day 7 or 14, having been obscured by either high mortality of early settlers, or large settlement events that took place after day 2. Thus the greatest impact of the pollution event occurred during the period of highest toxicant concentration. The value of this study lies in the correlation of toxicity effects with bio-available metal concentrations under realistic (natural, in situ) conditions.

Quantification of copper doses to settlement plates in the field using diffusive gradients in thin films.

Difficulty in estimating toxicant exposure has impeded the development of field-based experiments that examine the effects of toxicants in natural situations. In this study, diffusive gradients in thin films (DGT) were used to measure doses of copper delivered to settlement plates in the field over 30 days. Measurements were made at 4 sites near Melbourne, Australia, inside and outside of two enclosed marinas, and at two times designed to coincide with periods of warmest and coolest water. Dose was initially high, but dropped off sharply over the 30-day exposure period. Dose was affected by site, with more than an order of magnitude difference in the average dose between some sites. Hydrological factors were probably mainly responsible for the differences in dose observed. Dose varied with time of year, but the effect was site specific and was probably mediated by several factors. Measurements were affected by the presence of diffusive boundary layers and fouling, and procedures designed to eliminate the effects of diffusive boundary layers and fouling were highly sensitive to analytical errors and outlying data points. Despite this, the technique was able to show that field doses were comparable to those used in laboratory tests, and that acutely toxic conditions can be generated in natural situations.

Measurement of environmental trace-metal levels with transplanted mussels and diffusive gradients in thin films (DGT): a comparison of techniques.

Transplanted mussels and diffusive gradients in thin films (DGT) were used to assess levels of cadmium, copper, lead and zinc at four sites situated inside and outside of two enclosed marinas, near Melbourne, Australia. Mussels accumulated all metals except cadmium. Over one year, there were large temporal differences in tissue metal levels in mussels, but differences between sites were only apparent for copper and lead. DGT showed temporal differences of the same kind as those seen in the mussels, but appeared to have more power to discriminate between sites. DGT found higher copper levels inside marinas than outside, and high levels of zinc were found inside one marina. Levels of copper and zinc were high enough to be of environmental concern for one site. The effect of fouling on DGT measurements will have to be quantified, or avoided by the use of multiple short-term exposures, if the technique is to become a widespread in situ monitoring tool.