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.

A CASE STUDY ON STABILISER FIN-HULL INTERACTION USING CFD AND MODEL EXPERIMENTS

A case study was conducted to investigate and quantify stabiliser fin-hull interaction using a combination of Computational Fluid Dynamics and physical model experiments. The fin-hull interaction was studied by comparing the lift and drag of a stabiliser fin in a free stream condition and when attached to a hull. The findings of this case study showed that using free stream fin characteristics to predict performance of a stabiliser fin fitted to the hull resulted in an over-prediction of drag by up to 46% and under-prediction of lift by up to 75% for the speeds and angle of attack analysed. These discrepancies are for this case study only and in practice will vary for different hull forms, fin types, fin location and angles of attack. However, the research highlights the limitations of using free stream fin characteristics to predict the performance of a fin fitted to a hull.

Using Graph Networks to Quantify the Cumulative Importance of Riparian Wetlands within a Watershed

Wetlands provide many valuable ecosystem functions including nutrient cycling and retention, sediment capture, flood reduction, carbon storage, and habitat for water-dependent plant and wildlife species. The alteration of landscapes and the deterioration of upstream wetlands have been determined to be detrimental to downstream stream and watershed health. The position of the wetland in the landscape and its quality and size can significantly change the influence it has on stream condition. This research tests the efficacy of graphed networks created from the terrestrial-wetland-stream landscape to quantify the cumulative benefits of riparian wetlands within a watershed. We tested a combination of network parameters such as node degree, betweenness centrality, and the integral index of connectivity. Graphed networks are created by nodes that are connected by edges. Nodes were defined as stream reaches that extend out to the riparian landscape and edges as the stream confluences that connect them. Nodes were weighted by their capacity to perform ecosystem functions and the opportunity for such functions. We found that the network-based approach can quantify the impact of riparian wetland loss revealing that some riparian losses within the watershed were inherently worse than others at reducing connectivity and cumulative wetland function within the watershed. Incorporating these network metrics into wetland assessments can quantify the cumulative influence of geographic position, wetland function and size on overall wetland benefits within the watershed. This new approach can be applied to watershed planning efforts to assist managers with identifying wetlands for protection, enhancement, and re-establishment.

Importance of environmental flows in the Wimmera catchment, Southeast Australia

In this paper the environment, climate, vegetation, indigenous and European settlement history, stream flow patterns, water quality and water resources development in western Victoria, Australia are studied. The last part of the paper focuses on the MacKenzie River, a tributary of the Wimmera River located on the northern slopes of the Grampians Ranges in western Victoria, Australia. Water release along the MacKenzie River was regulated to improve water quality, stream condition and river health especially in the downstream reaches. The upstream section tends to receive water most days of the year due to releases to secure the requirements of water supply for the city of Horsham and its recreational and conservation values, which is diverted into Mt Zero Channel. Below this the middle and downstream sections receive a more intermittent supply. Annually, a total of 10,000 dam3 of water is released from Wartook Reservoir into the MacKenzie River. Of this volume, only about 4,000 dam3 was released explicitly for environmental purposes. The remaining 6,000 dam3 was released to meet consumptive demands and to transfer water to downstream reservoirs. The empirical data and models showed the lower reaches of the river to be in poor condition under low flows, but this condition improved under flows of 35 dam3 per day, as indicated. The results are presented to tailor discharge and duration of the river flows by amalgamation of consumptive and environmental flows to improve the condition of the stream, thereby supplementing the flows dedicated to environmental outcomes. Ultimately the findings can be used by management to configure consumptive flows that would enhance the ecological condition of the MacKenzie River.

Formulation of a multi-scale watershed ecological model using a statistical approach

The purpose of this special report is to provide a statistical stepwise process for formulation of ecological models for application at multiple scales using a stream condition index (SCI). Given the global variability of aquatic ecosystems, this guidance is for broad application and may require modification to suit specific watersheds or stream reaches. However, the general statistical treatise provided herein applies across physiographies and at multiple scales. The Duck River Watershed Assessment in Tennessee was used, in part, to develop and test this multiscale, statistical approach; thus, it is considered a case example and referenced throughout this report. The findings of this study can be utilized to (1) prioritize water-sheds for restoration, enhancement, and conservation; (2) plan and conduct site-specific, intensive ecosystem studies; and (3) assess ecosystem outcomes (that is, ecological lift) applicable to future with and without restoration actions including alternative, feasibility, and cost-benefit analyses and adaptive management.

Marketing to Gamers

Video game streaming has introduced to consumers a new method of creating branded content. Popular streaming platforms receive millions of broadcasters and viewers every month, and the current chapter examines the influence of this type of user-generated content on consumers' attitudes and behaviors. The goal of this study is to understand how video game streams function as a marketing tool. To investigate this, a quantitative survey was designed and measured participants' video gaming habits and their perceptions of credibility, usefulness of content, group identification, and purchase intention. Heavier gaming habits were found to be positively related to perceived credibility in a user-generated stream condition. Group identification and stream familiarity were found to be positively related to perceived credibility. These findings hold implications for using video game streams as a marketing tool as heavier gamers were found to perceive user-generated streams as a credible source of information.

A multi-component indicator of stream condition for waterway managers: balancing scientific rigour with the need for utility

Measuring the environmental condition of waterways is of interest to river managers,governments and the community. In the State of Victoria, Australia and elsewhere,there is concern that environmental values of streams are declining and that informationabout the environment, needs to be considered when river management decisions arebeing made.This thesis explores the use of environmental indicators as a tool to assist managementof rivers. The promise of indicators is that they can turn large amounts ofenvironmental data into simple, timely results and thereby provide an effective means ofincorporating this information into river management decisions. It is also suggested thatindicators will be useful for measuring the outcomes of management intervention andprovide feedback on the effectiveness of strategies.Can environmental indicators live up to this promise? This thesis examines thisquestion by reviewing indicator systems that have been developed by others and thenexploring, in detail, the Index of Stream Condition (ISC) that is intended as a tool toassist the management of rivers in Victoria. I argue that environmental indicators havea role at the level of regional waterway management authorities but only if they areclosely aligned with managers' needs. Without consideration of non-technical issues,indicators are unlikely to be used, so it is important to establish a balance betweenpragmatic constraints and the need for scientific rigour. A procedure to achieve thisbalance is described in this thesis and was applied to the development of the ISC.Selection of indicators and the choice of indicator frameworks are explored and thevalue judgements behind the interpretation of indicator scores are examined.It is also important to consider the accuracy and sensitivity of indicators. Possibleobjectives for the use of indicators include benchmarking, detecting change andproviding information to trigger management intervention. Case studies are used toexplore the performance of indicators in practical applications in streams in Victoria inrelation to these objectives. Extensive use is made of non-traditional statisticalprocedures, including bootstrapping, and results are presented that show the likelyvariance of indicator scores and the relationship between indicator objectives andrequired sampling effort.