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An enduring challenge for environmental governance is how to coordinate multiple actors to achieve more collaborative and holistic management of complex socio-ecological systems. Catchment partnerships are often thought able to achieve this, so here we ask: do such partnerships actually help navigate complexity, or merely add to it? We answer this question by analysing the experiences of four voluntary UK catchment partnerships. Our data combined a structured desk-based analysis of partnership documents, with semi-structured interviews with partnership coordinators, chairs and partner representatives. These data were analysed using a qualitative thematic approach informed by the literatures on catchment management and collaborative governance of complexity. We found that partnerships both add to and help navigate the complexity of holistic and inclusive environmental management. Maintaining partnerships entails costs for partners, and partnerships connect messily and multitudinously to other initiatives. However, the partnerships were all judged as worthwhile, and made progress towards goals for water quality, biodiversity and river restoration. They were especially valued for envisioning and initiating complex activities such as Natural Flood Management. Communication and networking by partnership coordinators and partners underpinned these achievements. Aspects of pre-existing governance systems both enabled and constrained the partnerships: in particular, statutory agencies responsible for policy delivery were always important partners, and delivering partnership plans often depended on public-sector grants. This draws attention to the pervasive effect of governmentality in collaborative governance. More attention to analysing—and supporting—such partnerships is worthwhile, complemented by reflection on the limits to environmental governance in the face of complexity. [ABSTRACT FROM AUTHOR]

Temporary storage areas (TSAs) represent a category of soft‐engineered nature‐based solutions that can provide dispersed, small‐scale storage throughout a catchment. TSAs store and attenuate surface runoff, providing new additional storage during flood events. The need for such additional catchment storage will become more urgent as the frequency and magnitude of extreme hydrological events increases due to climate change. Implementation of TSAs in headwater catchments is slowly gaining momentum, but practitioners still require further evidence on how such measures function during flood events. This review focuses on the role of relatively small‐scale (<10,000 m3) TSAs in headwater catchments for flood risk management. It also explores the potential wider benefits for implementing these as part of an integrated catchment management approach. TSA flood mitigation effectiveness is primarily determined by the TSA's available storage prior to the event. At the local scale, this can be represented by the relationship between TSA inputs, outputs and total storage. Factors influencing the local functioning and effectiveness of TSAs are discussed, with potential considerations for optimizing future TSA design and management. Hydrological models have suggested that TSAs could be used to effectively attenuate high magnitude events. However, future considerations should involve addressing the lack of empirical evidence showing TSA catchment scale effectiveness and how local TSA functioning might change in time. Small‐scale headwater TSAs offer a holistic and sustainable approach to catchment management that can deliver both local benefits to landowners and wider flood risk mitigation for society. This article is categorized under:Engineering Water > Sustainable Engineering of WaterScience of Water > Water ExtremesScience of Water > Hydrological Processes [ABSTRACT FROM AUTHOR]

This study evaluated historical land-cover states in order to identify potential land-use transition regimes leading to land degradation. Landsat satellite datasets were used to characterize land-cover states for 1986–2017 period. The multinomial probability distribution was used to establish sample size for training and accuracy assessment. Using a hybrid image classification approach, individual satellite images were initially clustered using the ISODATA technique, and spectral classes later transformed posteriori into respective thematic classes. Maximum Likelihood Function was subsequently used to assign pixels into classes with highest probability. Approximately 12% of mixed forest declined, while cropland increased by 30% between 1995–2008. [ABSTRACT FROM AUTHOR]

In this paper, nature‐based solutions (NBS) include: (1) natural flood management (NFM) interventions with a primary function of flood risk reduction but with additional multiple benefits for water quality improvements through the mitigation of diffuse pollution; and (2) ponds with a primary function of water quality improvement. This study assesses the ability of these NBS to trap pollutants in run‐off within two small (3.4 km2) agricultural catchments (Upper Thames, UK). The masses of sediment, phosphorus, and organic carbon trapped by 14 features (since construction 2–3 years previously) were quantified through sediment surveying and sampling. Streamflow and suspended sediment monitoring downstream of features enabled catchment yields to be calculated. The features trapped a total of 83 t sediment, 122 kg phosphorus, and 4.3 t organic carbon. Although the footprint of the features was <1% of the catchment area, they drained 44% of the total land area and captured the equivalent of 15% of the total suspended sediment yield, 10% of the total phosphorus yield, and 8% of the particulate organic carbon yield as monitored at the catchment outlet over the monitoring period. Results reveal that accumulation rates were influenced by hydrological connectivity, with greater accumulation in features constructed directly on streams (online ponds), and those offline features that filled from overbank flows. The low to moderate accumulation rates observed in offline features suggests that their floodwater storage potential is only likely to significantly reduce in the medium term, necessitating maintenance after ~10 years. Compared with topsoil in each contributing area, trapped sediment was enriched in phosphorus and carbon in the majority of features, having on average 50% higher phosphorus and 17% higher organic carbon concentrations than surrounding arable soils, highlighting its potential value for redistribution on farmland. Monitoring results demonstrate the potential of NBS, including NFM, to mitigate diffuse pollution in lowland catchments. [ABSTRACT FROM AUTHOR]

Natural Flood Management (NFM) and catchment-based solutions for flood risk management and environmental problems are wide-ranging and complex. Management of fluvial flood risk in the UK is undergoing a fundamental shift, with a change in emphasis from solely working with structural defences to considering catchment-based measures which attenuate flood runoff. At the heart of this change are NFM and nature-based solutions. One key type of intervention is the Runoff Attenuation Feature (RAF): a class of features that targets runoff flow pathways and creates new temporary flow storage (such as ponds and leaky barriers). However, there is currently a lack of evidence for the effectiveness of NFM and RAFs at larger catchment scales and for managing extreme flood events. Nevertheless, there is a strong evidence base to suggest that well-designed RAFs deliver a range of ecosystem services if installed in the correct location. This paper reviews and critiques the role of RAFs and NFM as an interventionist and holistic approach to lowering runoff rates. The link between RAF design types and their relationship to land use and scale is made. Recent novel innovations and attempts to scale up RAFs are discussed. The role of antecedent conditions, groundwater and the change in residence time of processes is highlighted. The uncertainty and complexity of proving NFM effectiveness underpin a view that new thinking in catchment flood management is needed. New research is required, and many questions are raised about RAFs and NFM. The direction of travel is that a positive and proactive NFM community can now embrace the problem. Proof that RAFs and NFM can address flood management is not likely to be resolved without a great deal of further research but confidence that RAFs do beneficial work is growing and an argument for greater amounts of runoff attenuation is made. [ABSTRACT FROM AUTHOR]

Freshwater catchments can experience nutrient deficits that result in reduced primary and secondary productivity. The most commonly limiting nutrients are nitrogen and phosphorus, either separately or together. This review considers the impact of increasing nutrient limitation in temperate basin stream and river systems, focusing on upland areas that currently or previously supported wild Atlantic salmon (Salmo salar) populations.Anthropogenic changes to land use and increases in river barriers have altered upland nutrient dynamics, with particular impacts on salmon and other migratory fish species which may be net importers of nutrients to upland streams. Declining salmon populations may further reduce nutrient sources, reducing ecosystem and fisheries productivity below desired levels.Experimental manipulations of nutrient levels have examined the impacts of this cultural oligotrophication. There is evidence that growth and biomass of juvenile salmon can be increased via appropriate additions of nutrients, offering potential as a conservation tool. However, further research is required to understand the long‐term effects of these additions on salmon populations and stream ecosystems, and to assess the vulnerability of downstream habitats to eutrophication as a result.Although purposeful nutrient addition with the aim of enhancing and conserving salmonid populations may be justified in some cases, it should be undertaken in an adaptive management framework. In addition, nutrient addition should be linked to nutrient retention and processing, and integrated into large‐scale habitat restoration and recovery efforts.Both the scientific and the management community should recognize that the ecological costs and benefits associated with adding nutrients to salmon streams may change in a non‐stationary world. [ABSTRACT FROM AUTHOR]

Flow–ecology relationships within river systems are an important area of ongoing investigation, because of potential applications such as understanding the ecological impact of flow alteration at modified sites. This study analyses relationships between flow characteristics and benthic macroinvertebrates from 18 streams of similar size and typology within Northern England, to develop quantitative flow–ecology relationships applicable at regional scale. High and low flow event frequencies displayed statistically significant relationships with the ecological metrics of LIFE Score, Shannon's Diversity and a velocity flow affinity trait score. Results suggest that flow event frequencies have a significant role in influencing ecology within the river network system. Hence, this indicates that future flow regime design in the region may be enhanced if this variable is considered. [ABSTRACT FROM AUTHOR]

Dam construction threatens global aquatic biodiversity by fragmenting stream networks and altering flow regimes. The negative effects of dams are exacerbated by increased drought periods and associated water withdrawals, especially in semi‐arid regions. Stream fishes are particularly threatened owing to their mobile nature and requirement for multiple habitats to complete their life cycles. An understanding of relationships with fragmentation and flow regimes, particularly as coarse‐scale (e.g. catchment) constraints on species distributions, is essential for stream fish conservation strategies.Prairie chub (Macrhybopsis australis) is a small‐bodied minnow (Cyprinidae) with poorly understood ecology endemic to the North American Great Plains. Suspected declines in abundance and extirpations have resulted in conservation interest for prairie chub at state and federal levels. Prairie chub is thought to share its reproductive strategy with pelagic‐broadcast spawning minnows (pelagophils). Freshwater pelagic‐broadcast spawning fishes have been disproportionately affected by fragmentation and streamflow alteration globally.Relationships of prairie chub occurrence with coarse‐scale fragmentation and streamflow metrics were examined in the upper Red River catchment. Occurrence probability was modelled using existing survey data, while accounting for variable detection. The modelled relationships were used to project the distribution of prairie chub in both a wet and dry climatic period.The probability of prairie chub occurrence was essentially zero at sites with higher densities of upstream dams, but increased sharply with increases in flow magnitude, downstream open mainstem, and flood duration. The projected distribution of prairie chub was broader than indicated by naïve occurrence, but similar in both climatic periods. The occurrence relationships are consistent with the hypotheses of pelagic broadcast spawning and represent coarse‐scale constraints that are useful for identifying areas of the stream network with higher potential for finer‐scale prairie chub conservation and recovery efforts. In addition to informing pelagophil conservation, the relationships are also applicable to pelagic‐broadcast spawning fishes in marine environments. [ABSTRACT FROM AUTHOR]

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Few conservation studies have examined fish communities in entire drainage basins, especially in developing regions such as Southeast Asia, one of the most diverse biomes globally. The aim of this study was to establish conservation projections for the whole of the Irrawaddy River system, based on fish diversity patterns, human impact, and environmental change.The Irrawaddy River is one of the five largest rivers in Southeast Asia. Although it has very high diversity of fish species and species endemism, our understanding of resident fish status remains poor.Based on 1,726 field survey and 1,056 database records, 470 fish species and their distribution patterns (i.e. alpha, beta, threatened species, and endemic species diversities) in sub‐basins of the Irrawaddy drainage were identified. Canonical correspondence analysis of diversity and environmental patterns indicated that climatic factors had the largest effect on diversity, compatible with the species–energy theory.Fish conservation priorities of sub‐basins were evaluated based on diversity patterns and human impact. The delta and Manipur basin regions were highlighted as areas of focus for future fish diversity conservation, and the importance of connectivity in the Irrawaddy main stem was demonstrated.The results of this study will be valuable for future management of the Irrawaddy basin and as a reference for other river basins when implementing protection strategies for fish diversity. This study also advocates the need for systematic investigations across entire drainage basins and further detailed studies on the ecological conditions of poorly studied river systems. [ABSTRACT FROM AUTHOR]

The Amazon River basin contains a vast diversity of lotic habitats and accompanying hydrological regimes. Further understanding the spatial distribution of flow regimes across the Amazon can be useful for recognizing riverine ecohydrological processes and informing river management and conservation, especially in areas with limited or inconsistent streamflow monitoring.This study compares four inductive approaches for classifying streamflow regimes across the Amazon using an unprecedented compilation of streamflow records from Bolivia, Brazil, Colombia, Ecuador, and Peru.Inductive classification schemes use attributes of streamflow data to categorize river reaches into similar classes, which then may be generalized to understand streamflow behaviour at the basin scale. In this study, classification was accomplished through hierarchical clustering of 67 flow metrics calculated using indicators of hydrologic alteration (IHA) and daily streamflow data from median annual hydrographs (MAHs) for 404 stations (representing >7,000 station‐years) across five Amazonian countries.Classification was performed using both flow magnitude‐inclusive and flow magnitude‐independent datasets. For flow magnitude‐independent methods, optimal solutions included six or seven primary hydrological classes for IHA and MAH datasets; for approaches that retained magnitude, variance was sufficiently large to prevent convergence to a specific number of classes.Across methods, class membership was strongly associated with the timing, frequency, and rate of change of flow, and spatially coherent clusters were associated with seasonal, elevational, and stream‐order gradients. These results highlight the diversity of flow regimes across the Amazon and provide a framework for studying relationships between hydrological regimes and ecological responses in the context of changing climate, land use, and human‐induced hydrological alteration.The methodology applied provides a data‐driven approach for classifying flow regimes based on observed data. When coupled with ecological knowledge and expertise, these classifications can be used to develop ecohydrologically informed and management‐relevant conservation practices. [ABSTRACT FROM AUTHOR]

Payment for Ecosystem Service (PES) schemes is increasingly being used to obtain and drive environmental improvements. This paper describes two PES schemes, designed by Severn Trent Water (STW) to manage metaldehyde; Farm to Tap, and Product Substitution. Data collected over three years of running the schemes indicate that they can reduce the mean metaldehyde concentration at the Water Treatment Works by up to 61%; however, in‐catchment concentrations are more variable. Participant usage and behavioural surveys identify that the majority of farmers will use multiple methods to manage their slug problem. Farmer initiatives developed where rewards are paid for metaldehyde reductions, regardless of the process(es) used (Farm to Tap), result in 12% more metaldehyde reduction than when product substitution is used alone. Going forward, catchment management is the long‐term, economic and sustainable option. Schemes like Farm to Tap and Product Substitution are crucial to achieve water quality improvements and wider environmental benefits. [ABSTRACT FROM AUTHOR]

Future climate change will likely impact the multiple freshwater ecosystem services (fES) provided by catchments through their landscapes and river systems. However, there is high spatio-temporal uncertainty on those impacts linked to climate change uncertainty and the natural and anthropogenic interdependencies of water management systems. This study identifies current and future spatial patterns of fES production in a highly managed water resource system in northern India to inform the design and assessment of plausible adaptation measures to enhance fES production in the catchment under uncertain climate change. A water resource systems modelling approach is used to evaluate fES across the full range of plausible future scenarios, to identify the (worst-case) climate change scenarios triggering the greatest impacts and assess the capacity of adaptation to enhance fES. Results indicate that the current and future states of the fES depend on the spatial patterns of climate change and the impacts of infrastructure management on river flows. Natural zones deliver more regulating and cultural services than anthropized areas, although they are more climate-sensitive. The implementation of a plausible adaptation strategy only manages to slightly enhance fES in the system with respect to no adaptation. These results demonstrate that water resource systems models are powerful tools to capture complex system dependencies and inform the design of robust catchment management measures. They also highlight that mitigation and more ambitious adaptation strategies are needed to offset climate change impacts in highly climate-sensitive catchments. [ABSTRACT FROM AUTHOR]

Hydrological catchments today are largely the product of human activity. They have been engineered. The negative impacts of some of this engineering such as deforestation and agriculture intensification need to be addressed but the solution is not simply a matter of doing the opposite, for example through afforestation or moving to less‐intensive farming. We propose a catchment systems engineering (CSE) approach that utilizes and expands on existing catchment‐based approaches, combining interventions that work with or mimic natural processes with traditional "hard" engineering to provide a practical route to improved catchment function. The approach is predicated on the need to take an holistic view of catchments and to make proactive interventions that provide and enhance multiple ecosystem services. CSE seeks to address problems that are international in scope, recognizing the need to understand better how hydrological processes have changed due to human activity and how those changes influence frequency, duration, and severity of environmental problems such as floods, droughts, and poor water quality. The emphasis is placed on how we can act to engineer catchment systems to a safer functionally appropriate level utilizing measures such as nature‐based solutions alongside traditional engineering structures. CSE is the means to provide multiple ecosystem services while recognizing trade‐offs between reducing flood and drought risk directly, improving water quality and creating healthy habitats for wildlife. By targeting local hydrological flow pathways in defined spatial and temporal windows (e.g., during rainfall events at key locations such as riparian zones), CSE can deliver holistic water resource management now. This article is categorized under:Engineering Water > Sustainable Engineering of WaterEngineering Water > Planning WaterScience of Water > Water ExtremesWater and Life > Conservation, Management, and Awareness [ABSTRACT FROM AUTHOR]

Understanding the natural low flow of a catchment is critical for effective water management policy in semi‐arid and arid lands. The Geba catchment in Ethiopia, forming the headwaters of Tekeze‐Atbara basin was known for its severe land degradation before the recent large scale Soil and Water conservation (SWC) programs. Such interventions can modify the hydrological processes by changing the partitioning of the incoming rainfall on the land surface. However, the literature lacks studies to quantify the hydrological impacts of these interventions in the semi‐arid catchments of the Nile basin. Statistical test and Indicators of Hydrological Alteration (IHA) were used to identify the trends of streamflow in two comparatives adjacent (one treated with intensive SWC intervention and control with fewer interventions) catchments. A distributed hydrological model was developed to understand the differences in hydrological processes of the two catchments. The statistical and IHA tools showed that the low flow in the treated catchment has significantly increased while considerably decreased in the control catchment. Comparative analysis confirmed that the low flow in the catchment with intensive SWC works was greater than that of the control by >30% while the direct runoff was lower by >120%. This implies a large proportion of the rainfall in the treated catchment is infiltrated and recharge aquifers which subsequently contribute to streamflow during the dry season. The proportion of soil storage was more than double compared to the control catchment. Moreover, hydrological response comparison from pre‐ and post‐intervention showed that a drastic reduction in direct runoff (>84%) has improved the low flow by >55%. This strongly suggests that the ongoing intensive SWC works have significantly improved the low flows while it contributed to the reduction of total streamflow in the catchment. [ABSTRACT FROM AUTHOR]

Sediment source fingerprinting apportions the sources of sediment produced by water erosion by linking sampled sediment mixtures and landscape source materials using diagnostic and conservative fingerprints. Using this approach, the nature and location of active sediment sources across the catchment can be elucidated, generating information which is a key prerequisite for the design and implementation of catchment management strategies. The science of sediment source fingerprinting continues to attract much research globally, but to date, there have been relatively few fingerprinting studies in China. Here, there remain major challenges for the fingerprinting approach arising from the uniqueness of Chinese landscapes, including for instance, the complex land use configuration with highly fragmented or mosaic patches and the highly dynamic land use conversion rates, generating a need to test the physical basis for the discriminatory power and environmental behavior of both traditional and novel tracers. Future research is needed to investigate the applicability of tracer properties in different physiographic settings and to evaluate the potential strategic utility of the approach for supporting the improved management of soil and water sustainability. Here, the strategic availability of independent observation data for different components of catchment sediment budgets and well-maintained research infrastructure for plots, micro-catchments and drainage basins provides immediate opportunity for testing the approach and refining procedures. Such detailed testing across scales would be invaluable for promoting sediment source fingerprinting as both a scientific and management tool for informing soil and water conservation practices in China. [ABSTRACT FROM AUTHOR]

• A strategic risk-screening approach to water quality has been applied in Scotland. • Screening identified dominant risk factors and higher-risk catchments. • Risks were highlighted for colour and linked to management of organic soils. • Bacteriological quality parameters were linked to agricultural land uses. • Risks are likely to be further modified by land use changes and climate change. Water resources provide multiple services, one of the most important the provision of drinking water, conventionally treated before public consumption as potable supplies. With increasing pressures from land use and climate change, there are advantages to be gained from considering raw water quality as a fundamental characteristic of the natural resource, and to anticipate emerging risks within the catchments rather than relying on treatment. This research proposes a large-scale, rapid risk screening of raw water quality based on catchment sensitivity to pressures as prerequisite to a more strategic inclusion of emerging risks in water resource and ecosystem management. Raw water quality observations from 154 surface water catchments in Scotland were investigated to determine the national baseline and to identify current pressures and underlying drivers. Patterns and spatial dependencies were investigated using principal component analysis, redundancy analysis, cluster analysis, and regression trees. These statistical approaches highlight the interaction between intrinsic catchment biophysical properties, land use and climate in characterising water quality risks and identify the focus for prioritising catchment interventions and risk-mitigation in the future. The emphasis on raw water quality will also support an ecosystem-based approach to increase catchment resilience, to ensure long-term supply of good quality drinking water while simultaneously creating wider benefits for society and the environment. [ABSTRACT FROM AUTHOR]

In many wetlands the timing and duration of inundation determine ecological characteristics and the provision of ecosystem services; however, wetland conservation decisions often rely on static maps of wetland boundaries that do not capture their dynamic hydrological variability and connectivity.The Amazon River basin contains some of the world's most extensive wetlands, many of which are floodplains where seasonal flood pulses result in a temporally varying inundation area and hydrological connectivity with river systems.This study classified Amazon wetlands according to the timing and duration (months per year) of inundation detected by remote sensing, and also investigated the contribution of precipitation regimes in affecting wetland distribution and hydrological dynamics.Permanently inundated wetlands account for the largest area and are mainly floodplains located in the lowlands of the catchment. Seasonally inundated wetlands varied greatly in the duration of inundation over the course of the year, ranging from 1 to 9 months. Distinct seasonal timing was detected among the large wetland complexes, reflecting rainfall regimes as well as time lags for drainage and drying. For example, inundation in the extensive Llanos de Moxos region of the southern Amazon was protracted and lasted well after the rainy season, compared with the Roraima region of the northern Amazon, where inundation was shorter and tracked the rainy season.The integration of inundation dynamics into wetland classification captures regional differences in timing and duration of inundation in the major wetlands of the basin that should be considered for conservation planning and other ecological applications. This information can aid regional wetland management and planning, especially with regards to minimizing the effects of dam and waterway construction that can directly affect the natural wetland dynamics. The use of global remotely sensed inundation data makes this approach easily transferable to other large tropical wetlands. [ABSTRACT FROM AUTHOR]

Abstract Catchment-scale water quality models have become important tools for water quality management, planning and reporting worldwide. In this review, we synthesise recent developments in water quality modelling, focusing on catchment-scale models of freshwater, non-urban systems and their ability to support catchment management. We explore 10 key attributes in selected existing water quality models. These attributes can be characterised as: model use (model purposes, representation of constituents, scenario analysis, and documentation), model development (process representation, spatial heterogeneities, temporal dynamics, and data requirements), and model performance (calibration, validation and uncertainty tools). We deliberate on 11 key challenges and/or emerging topics in catchment water quality modelling: large-scale applications, model integration, model usability and communication, preliminary data analysis, modelling management practices, technology advancement, incorporating soft data, model identifiability, uncertainty analysis, good modelling practices and capacity building, and differentiating the effects of climate impacts from those associated with land use and management practices. Highlights • The review focuses on the ability of models to support catchment management. • Key attributes of model use, development and performance were explored. • We discussed 11 challenges and emerging topics for future development. • Uncertainty can be reduced through using soft data and optimal monitoring design. • A major challenge is separating impacts of climate from land use and management. [ABSTRACT FROM AUTHOR]

• Multiple buffer zone and catchment management options exist to conserve the study freshwater ecosystem. • The co-developed and designed management options support to address the complex challenges. • Co-developing management options should take short-term economic benefits and long-term environmental goals into account. • Putting adaptive learning in place support to adapt the management options with the changing socio-ecological context. • Capacitating local level practitioners through on job trainings and knowledge co-production is crucial. Freshwater ecosystems are important for directly ensuring a range of benefits and services that sustain local livelihoods and help mitigate climate change. However, freshwater ecosystems are threatened by anthropogenic and natural pressures affecting their ability to sustainably provide these services. Managing freshwater ecosystems is mainly challenged by the complexity of the drivers of their degradation and by the difficulty of balancing the need for short-term socioeconomic development and protecting and restoring ecosystems to support long-term, sustainable development. Addressing such challenges requires an integrated and systematic approach, catchment-wide management and meaningful engagement and collaboration among stakeholders. The present study was conducted in Lake Ziway, Rift Valley Lakes Basin, Ethiopia. The overarching objective was to conserve the freshwater ecosystem through co-planning and designing management options for the buffer zone and entire catchment. The study engaged local communities through multiple approaches including inception and validation workshops, reconnaissance surveys, key informant interviews and focus group discussions. It also employed quantitative data collection methods to characterize the freshwater ecosystem and entire catchment. The participatory approach employed in this study identified multiple management options including tree-based forest and landscape restoration measures, integrated soil and water conservation, and multiple buffer zone restoration measures. The identified and validated management options are aimed at improving the functionality of the freshwater ecosystem in the face of increased need of economic development and climate change. Furthermore, the study provided key recommendations to support the processes of policy development and the effective implementation of suggested and validated management options. [ABSTRACT FROM AUTHOR]

A bstract Knowledge of temporal variations in river hydraulic characteristics (i.e., width, depth, velocity) across stream networks is a key element for catchment management because hydraulics influence physical habitats and biodiversity, water temperature, nutrient fluxes, sediment transport and associated ecosystem services. Reach scale at-a-station hydraulic geometry describes the variation of mean water depth and width with discharge within a stream reach. The ability to understand and predict the form of these hydraulic geometry relationships across river networks therefore represents a powerful tool for river managers. Although variations of these relationships between rivers have been widely documented, they are still largely unexplained. This study provides an analysis of a unique data set of hydraulic geometry collected in 492 stream reaches in France. Relationships between the hydraulic geometry parameters and many variables describing catchment- and reach-scale characteristics of reaches were analyzed using stepwise linear regression and discriminant analysis. Results show that width-discharge relationships across reaches are well predicted by longitudinal and lateral descriptors of reaches: the ratio of median to bankfull width, the median Froude number, the width to depth ratio, the active channel relative to the catchment area and the fluvial pattern (braided or not). Fluvial pattern, reach averaged active channel width and bankfull width can be accurately estimated using aerial imagery, making application of our models over river networks possible. Fewer relationships significantly explained depth-discharge relationships, despite a weak influence of reach Froude number, flow resistance (i.e., relative grain size, relative bedform submergence) and width to depth ratio. Unavailable descriptors of channel resistance would probably improve these models (e.g., describing bank stability, spill and form resistance). Despite the uncertainties of hydraulic geometry relationships, this study shows that predictions of hydraulic geometry exponents across river networks are possible, offering a large range of potential applications. H ighlights • We analyzed hydraulic geometry measured at two discharges in 492 reaches. • We predicted at-a-station hydraulic changes from aerial images, GIS and field data. • Width-discharge relationships strongly depend on longitudinal and lateral morphology. • Depth-discharge relationships are not well explained and influenced by roughness. • Our models may contribute to large scale hydrologic, habitat and sediment modeling. [ABSTRACT FROM AUTHOR]

Highlights • Dominant sediment sources contrasted between intensive agricultural catchments. • Greater field contributions when connectivity occurred on low groundcover soils. • Channel sediments were dominant sources in two catchments. • Sediment connectivity fluctuations could explain source changes over time. • Targeted sediment policies should be prioritised in intensifying catchments. Abstract Management strategies to reduce soil loss and sediment delivery from agricultural land requires an empirical understanding of sediment sources. Sediment fingerprinting is a technique to apportion sources to a downstream sediment sample which, when applied at high spatial and temporal resolutions, can offer insights into catchment sediment dynamics. However, developing an over-arching tool can be hindered due to indeterminate interactions such as, for example, landuse, soil and geological conditions and multiple sediment source pressures. To address this, a multi-proxy sediment fingerprinting approach was used in three catchment observatories in Ireland, characterised and referred to by their predominant soil drainage and land use characteristics: poorly-drained grassland, well-drained arable and moderately-drained arable. Potential sediment source groups: channels, field topsoils, and roads, were sampled. Target sediment samples were collected from six sites within each catchment over approximately two-years from May 2012 to May 2014. Geochemical, mineral magnetic and radionuclide tracers were measured in source and target sediment samples and, following justified tracer selection, source proportions were estimated using an uncertainty inclusive un-mixing model. Overall, the poorly-, well- and moderately-drained catchments exported 828, 421 and 619 tonnes, respectively (36, 19 and 33 t km−2 yr-1). Estimated source contributions from channel, field topsoil and road groups were overall, 67%, 27% and 4% in the poorly-drained grassland, 53%, 24% and 24% in the well-drained arable and 9%, 82% and 8% in the moderately-drained arable catchment outlets. Sub-catchment source estimates were generally consistent with the catchment outlet over space and time. Short-term activation of previously unidentified transport pathways were detected, for example, field sources transported by the road network in the well-drained catchment. In catchments with high hydrological surface connectivity (moderate and poor soil drainage), exposed soils were most sensitive to soil erosion and sediment delivery. Where groundcover is maintained on these soils, sediment connectivity was diminished and flow energy is transferred to the stream network where channel bank erosion increased. In the well-drained arable catchment, sub-surface flow pathways dominated and consequently channel sources, broadly representative of subsoil characteristics, were the largest sediment source. Sediment connectivity contrasted in the studied agricultural catchments according to source availability, and erosion, transport and delivery processes. Effective sediment management strategies in intensive and intensifying agricultural catchments must consider sediment loss risk resulting from catchment specific sediment connectivity and emphasise mitigation strategies accordingly. [ABSTRACT FROM AUTHOR]

Abstract: Despite being designated the first UNESCO Biosphere Reserve in Malaysia, the Chini Lake Basin experiences continuing management challenges attributable to existing sectoral management practices and differences in demands of multiple stakeholders. Accordingly, a socio‐economic survey and stakeholder consultative process were undertaken, involving relevant stakeholders in the lake basin. The consultative process involved: (a) identification and prioritization of relevant stakeholders; (b) assessment of their socio‐economic activities and perceptions; (c) organization of focus group discussions between basin stakeholders; and (d) development of management recommendations in collaboration with stakeholders. The results of this study indicated the local community's way of living has changed from traditional occupations to a wage economy. Overlapping functions and lack of communication were among the major identified challenges facing by Chini Lake. Multiple strategies were proposed to promote environmental protection and good governance of Chini Lake, including formation of special area plans and strengthening institutional arrangements to sustainably manage the Chini Lake catchment. An effective authority also is necessary to improve communication and coordination of programmes by the various basin agencies and communities. [ABSTRACT FROM AUTHOR]

River basins are extremely complex hierarchical and directional systems that are affected by a multitude of interacting stressors. This complexity hampers effective management and conservation planning to be effectively implemented, especially under climate change. The objective of this work is to provide a wide scale approach to basin management by interpreting the effect of isolated and interacting factors in several biotic elements (fish, macroinvertebrates, phytobenthos and macrophytes). For that, a case study in the Sorraia basin (Central Portugal), a Mediterranean system mainly facing water scarcity and diffuse pollution problems, was chosen. To develop the proposed framework, a combination of process-based modelling to simulate hydrological and nutrient enrichment stressors and empirical modelling to relate these stressors - along with land use and natural background - with biotic indicators, was applied. Biotic indicators based on ecological quality ratios from WFD biomonitoring data were used as response variables. Temperature, river slope, % of agriculture in the upstream catchment and total N were the variables more frequently ranked as the most relevant. Both the two significant interactions found between single hydrological and nutrient enrichment stressors indicated antagonistic effects. This study demonstrates the potentialities of coupling process-based modelling with empirical modelling within a single framework, allowing relationships among different ecosystem states to be hierarchized, interpreted and predicted at multiple spatial and temporal scales. It also demonstrates how isolated and interacting stressors can have a different impact on biotic quality. When performing conservation or management plans, the stressor hierarchy should be considered as a way of prioritizing actions in a cost-effective perspective. [ABSTRACT FROM AUTHOR]

Future water scarcities in the face of an increasing population, climate change and the unsustainable use of aquifers will present major challenges to global food production. The ability of water footprints (WFs) to inform water resource management at catchment-scale was investigated on the Steenkoppies Aquifer, South Africa. Yields based on cropping areas were multiplied with season-specific WFs for each crop to determine blue and green water consumption by agriculture. Precipitation and evapotranspiration of natural vegetation and other uses of blue water were included with the agricultural WFs to compare water availability and consumption in a catchment sustainability assessment. This information was used to derive a water balance and develop a catchment WF framework that gave important insights into the hydrology of the aquifer through a simplified method. This method, which requires the monitoring of only a few key variables, including rainfall, agricultural production, WFs of natural vegetation and other blue water flows, can be applied to inform the sustainability of catchment scale water use (as opposed to more complex hydrological studies). Results indicate that current irrigation on the Steenkoppies Aquifer is unsustainable. This is confirmed by declining groundwater levels, and suggests that there should be no further expansion of irrigated agriculture on the Steenkoppies Aquifer. Discrepancies between in- and outflows of water in the catchment indicated that further development of the WF approach is required to improve understanding of the geohydrology of the aquifer and to set and meet sustainability targets for the aquifer. It is envisaged that this ‘working’ framework can be applied to other water-stressed aquifers around the world. [ABSTRACT FROM AUTHOR]

A distributed hydrological model (WaSiM-ETH) was applied to a mesoscale catchment to investigate natural flood management as a nonstructural approach to tackle flood risks from climate change. Peak flows were modelled using climate projections (UKCP09) combined with afforestation-based land-use change options. A significant increase in peak flows was modelled from climate change. Afforestation could reduce some of the increased flow, with greatest benefit from coniferous afforestation, especially replacing lowland farmland. Nevertheless, large-scale woodland expansion was required to maintain peak flows similar to present and beneficial effects were significantly reduced for larger “winter-type” extreme floods. Afforestation was also modelled to increase low-flow risks. Land-use scenarios showed catchment-scale trade-offs across multiple objectives meant “optimal” flood risk solutions were unlikely, especially for afforestation replacing lowland farmland. Hence, combined structural/nonstructural measures may be required in such situations, with integrated catchment management to synergize multiple objectives. [ABSTRACT FROM AUTHOR]

Protection of surface water quality is a key driver in catchment management, particularly for areas undergoing land use change. Changing land use can result in the input of a range of pollutants to surface waters, resulting in water quality impairment, leading to eutrophication and the appearance of algae blooms. This study investigated a mixed land use coastal catchment by undertaking extensive field sampling and data analysis for pollutant source characterisation. The objective was to contribute to a greater understanding of pollutant inputs to surface water resources and for effective catchment management. Based on data analysis results, a diversity of pollutant sources was noted, including both natural areas and areas subject to anthropogenic activities such as agriculture and urban developments, with agricultural areas being comparatively more significant in exporting nutrients. Additionally, pollutant inputs into estuarine and freshwater areas were found to have specific characteristics influenced by land use. The pollutant inputs from these sources were found to be significantly affected by seasonal factors, with the dominant pollutant sources differing between the wet and dry seasons. This underlines the importance of taking seasonal factors into account in the development of effective catchment management strategies. Based on the study outcomes, a critical point monitoring program was developed with a focus on preventing algae blooms. This will allow the development of a decentralised catchment management strategy where resource-efficient monitoring of critical pollutant parameters at key locations can be undertaken for minimising the risk from algae blooms, rather than implementing a whole of catchment and resource-demanding large-scale monitoring program. [ABSTRACT FROM AUTHOR]

Internationally, a wide set of measures are being considered to reduce flood risk: natural flood management ( NFM) is one of them. NFM includes a broad range of measures that alter, restore or use landscape features to manage flood risk. By working with catchment-wide hydrological and morphological processes, NFM aims to manage the sources and pathways of floodwaters. NFM can nevertheless conflict with other land uses, in particular agricultural food production. Our research aimed to explore farmers' perceptions of NFM and identify the criteria influencing decision making in implementation. Using findings from a workshop, qualitative interviews and a national survey carried out in Scotland, this paper identifies six key criteria that farmers consider when implementing NFM: economics, availability of advice and support, public perception, joined-up policy, catchment planning and traditions. While a number of these criteria are consistent with the agri-environment literature and other flood management studies, our study makes some novel findings regarding farmer perceptions and how NFM affects the farm business. We conclude that NFM installation could be encouraged through one-to-one advice from a trusted facilitator and long-term financial incentives that compliment other farm payments. This should be combined with a catchment approach to flooding, which highlights shared responsibility for reducing flood risk. [ABSTRACT FROM AUTHOR]

Floodplain meadows support a high level of botanical diversity because the nutrient inputs from flood sediments are balanced by nutrient offtake via an annual hay harvest, leading to nutrient neutrality. This prevents a build-up of nitrogen (N) and phosphorus (P) and depletes excess nutrients, which mitigates eutrophication in catchment areas and prevents reductions of biodiversity through competitive exclusion. A replicated field trial was undertaken in floodplain meadows in central England, with the aim of comparing the nutrient offtake potential throughout the growing season with a single or a double-cut system, and determining when haymaking should occur to maximise nutrient offtake and nutritional value of the hay. Additionally, farmer perspectives were gathered to investigate the practicality of implementing a second hay cut. The results revealed that a single summer hay cut may be sufficient to balance nutrient inputs. However, a double-cut, where a second harvest replaces autumn grazing, has the potential to actively lower N and P levels, removing 8.69 g m−2 N and 0.80 g m−2 P. Maximising time between cuts in a double-cut system provides the greatest opportunity for nutrient removal. Temperature is a key driver of plant growth. The relationship between accumulated thermal time and calendar date in central England has advanced by around two weeks between 1961–1990 and 1991–2020. Delayed hay cutting under agri-environment scheme restrictions may be increasingly detrimental to botanical diversity with advancing seasons, due to lower nutrient removal under a single-cut system, and increased competitive exclusion. Taking a first cut at the mid-summer peak in offtake potential, currently 20–30 June in central England, and a second cut in the autumn offers an opportunity to deplete excess nutrients. Whilst farmers identify practical and financial concerns that may make a second cut prohibitive in some cases, this could be overcome by, e.g., demonstrating the higher-than-expected nutritional value of hay from a second cut. [Display omitted] • Haymaking on floodplain meadows facilitates removal of excess nutrients. • A double hay cut can contribute to nutrient neutrality targets. • The time of year that hay is cut determines the nutrient content potential. • Mean thermal time has advanced by two weeks since 1961–1990 in central England. • Floodplain meadow hay can add value to a nature-friendly farming enterprise. [ABSTRACT FROM AUTHOR]

The effective management of sediment losses in large river systems is essential for maintaining the water resources and ecosystem services they provide. However, budgetary, and logistical constraints often mean that the understanding of catchment sediment dynamics necessary to deliver targeted management is unavailable. This study trials the collection of accessible recently deposited overbank sediment and the measurement of its colour using an office document scanner to identify the evolution of sediment sources rapidly and inexpensively in two large river catchments in the UK. The River Wye catchment has experienced significant clean-up costs associated with post-flood fine sediment deposits in both rural and urban areas. In the River South Tyne, fine sand is fouling potable water extraction and fine silts degrade salmonid spawning habitats. In both catchments, samples of recently deposited overbank sediment were collected, fractionated to either <25 μm or 63-250 μm, and treated with hydrogen peroxide to remove organic matter before colour measurement. In the River Wye catchment, an increased contribution from sources over the geological units present in a downstream direction was identified and was attributed to an increasing proportion of arable land. Numerous tributaries draining different geologies allowed for overbank sediment to characterise material on this basis. In the River South Tyne catchment, a downstream change in sediment source was initially found. The River East Allen was identified as a representative and practical tributary sub-catchment for further investigation. The collection of samples of channel bank material and topsoils therein allowed channel banks to be identified as the dominant sediment source with an increasing but small contribution from topsoils in a downstream direction. In both study catchments, the colour of overbank sediments could quickly and inexpensively inform the improved targeting of catchment management measures. • Overbank sediment colour showed its source evolution along two large rivers. • Hydrogen peroxide mitigated organic matter enrichment related uncertainties. • In the River Wye contributions were associated with an increasing arable land use. • In the River South Tyne river bank erosion dominated throughout its length. • Targets for management were rapidly and inexpensively determined. [ABSTRACT FROM AUTHOR]

Estimates of the amount of topsoil in river sediments can help constrain sediment budgets on decadal time scales. The tracers 137Cs and 210Pb(ex) are used to determine the proportion of topsoil in river sediments in two Himalayan catchments, a relatively simple but effective method that could be used in many catchments in this complex mountain range for management purposes. Different results are reached, apparently depending upon antecedent conditions, with a large component of topsoil in river sediments likely to be the result of rainfall that erodes hillslopes by sheet and rill processes, does not mobilize or mix with other sources of sediment such as from landslides, and does not generate high river flows to transport the topsoil downstream. These results show that sampling of tracers in sedimentary archives is essential to provide time series of topsoil input to Himalayan rivers to account for high temporal variability. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The ability of existing protected areas (PAs) to conserve freshwater species and ecosystems has been little investigated. In this study the freshwater conservation potential of PAs was evaluated based on their geospatial attributes and spatial relationship to threats., Specifically, the following questions were addressed: (a) to what extent, if any, do PA drainage network location and size affect the potential of PAs to conserve freshwater species and habitats within them?; (b) how are the factors that limit or promote conservation potential distributed in relation to PAs across a region?; and (c) what are the broader implications for how PAs can be designed and managed to contribute to freshwater conservation around the world?, Eight factors that affect freshwater conservation potential for 297 PAs within the Tennessee and Cumberland River Basins (US) were analysed. Four of these attributes (connectivity, impervious surface area, agricultural land cover, and upstream storage) showed enough variation across PAs such that the effect of PA size, drainage network position, and their interaction on those attributes, was able to be modelled., The results support the hypothesis that PA drainage network location and size affect freshwater conservation potential of PAs. Both have a statistically significant effect on each of the four conservation potential attributes, either as a main effect, or through an interaction, although the direction of these relationships is not always intuitive. Of the factors that limit or promote conservation potential, PAs appear to be most often affected by land conversion to agriculture and a loss of connectivity., This study underscores the importance of PA managers understanding key internal and external threats so that they can take mitigating or minimizing action, and the need to define PA locations and boundaries within a larger basin context., Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Water resource management is complex, and should ideally be a co-operative, stakeholder-driven problem-solving process. Bayesian networks (BNs) are one participatory tool being increasingly used to facilitate this process. The upper Mgeni catchment in the province of KwaZulu-Natal, South Africa, is a key water resource area with looming water quality problems. The high number of stakeholders involved in a catchment management forum provided an environment for testing the development of a BN showing relationships between water quality problems and stakeholders in this area. Through engagement with stakeholders at quarterly meetings during 2011, and collation and analysis of water quality time-series, qualitative and quantitative data were successfully translated into a BN for water quality improvement in the study area. The model demonstrated that certain water quality variables (for example, compliance of wastewater treatment works; increase in housing developments) were more likely to be the cause of problems than others (such as discharges from farm dams or accidental spills). The value of involving stakeholders in a co-operative process is highlighted, and it is argued that the robustness of such a model would be enhanced further if applied within a formal participatory approach using conditional probability values endorsed by all stakeholders. [ABSTRACT FROM AUTHOR]

ABSTRACT The precious coral Corallium rubrum is one of the most vulnerable resources in the Mediterranean Sea because of the high levels of human-related and natural mortality rates. The aim of the present study was to document the diversity and connectivity patterns among Sardinian Corallium rubrum populations focusing, in particular, on deep populations (>80 m depth) where the commercial exploitation is concentrated., Microsatellite markers revealed high levels of inbreeding, heterozygote deficits, and significant genetic differentiation between and within areas at different depths, with an associated 'isolation by distance' pattern., These results indicated that for precious coral populations in Sardinia the 'deep reef refugia hypothesis', that envisages the capacity for deep corals to act as seed banks for the shallower impaired (over-harvested) populations, is not supported., The highest genetic diversity recorded in Sardinia for all areas and depths with respect to other Mediterranean areas indicates that the strict local management has been effective, since harvesting has not yet led to a substantial erosion of the genetic pool., Possible causes for the high levels of observed diversity in Sardinia are discussed in relation to hydrological conditions, its geographical position and its proximity to some putative glacial refugia., Thus, given the occurrence in Sardinia of highly diverse and differentiated deep-water populations of C. rubrum whose genetic diversity are important for the long-term resilience of the species, the results of the present study strongly support the close monitoring of harvesting, along with the maintenance or even strengthening of the current management and conservation measures (no-take protected areas) already in place in the area., Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The application of models to predict concentrations of faecal indicator organisms (FIOs) in environmental systems plays an important role for guiding decision-making associated with the management of microbial water quality. In recent years there has been an increasing demand by policy-makers for models to help inform FIO dynamics in order to prioritise efforts for environmental and human-health protection. However, given the limited evidence-base on which FIO models are built relative to other agricultural pollutants (e.g. nutrients) it is imperative that the end-user expectations of FIO models are appropriately managed. In response, this commentary highlights four over-arching questions associated with: (i) model purpose; (ii) modelling approach; (iii) data availability; and (iv) model application, that must be considered as part of good practice prior to the deployment of any modelling approach to predict FIO behaviour in catchment systems. A series of short and longer-term research priorities are proposed in response to these questions in order to promote better model deployment in the field of catchment microbial dynamics. [ABSTRACT FROM AUTHOR]

Drained peatland catchments are reported to produce more colored, dissolved organic carbon (DOC)-rich water, presenting problems for potable water treatment. The blocking of peatland drainage ditches to restore the water table is increasingly being considered as a strategy to address this deterioration in water quality. However, the effect of ditch blocking on the potential of DOC to form trihalomethanes (THMs) has not been assessed. In this study, the effect of peat rewetting on pore water DOC concentration and characteristics (including THM formation potential [THMFP]) was assessed over 12 months using peat cores collected from two drained peatland sites. The data show little evidence of differences in DOC concentration or characteristics between the different treatments. The absence of any difference in the THMFP of pore water between treatments suggests that, in the short term at least, ditch blocking may not have an effect on the THMFP of waters draining peatland catchments. [ABSTRACT FROM AUTHOR]

The regional water allocation planning is one of those complex decision problems where holistic approach to water supply management considering different criteria would be valuable. However, multi-criteria decision making with diverse indicators measured on different scales and uncertainty levels is difficult to solve. Objective of this paper is to develop scenarios for the future imbalances in water supply and demand for a water stressed Mediterranean area of Northern Spain (Tarragona) and to test the applicability and suitability of an outranking method ELECTRE-III-H for evaluating sectoral water allocation policies. This study is focused on the use of alternative water supply scenarios to fulfil the demand of water from three major sectors: domestic, industrial and agricultural. A detail scenario planning for regional water demand and supply has been discussed. For each future scenario of climate change, the goal is to obtain a ranking of a set of possible actions with regards to different types of indicators (costs, water stress and environmental impact). The analytical method used is based on outranking models for decision aid with hierarchical structures of criteria and ranking alternatives using partial preorders based on pairwise preference relations. We compare several adaptation measures including alternative water sources (reclaimed water and desalination); inter basin water transfer and sectoral demand management coming from industry, agriculture and domestic sectors and tested the sustainability of management actions for different climate change scenarios. Results have shown use of alternative water resources as the most reliable alternative with medium reclaimed water reuse in industry and agriculture and low to medium use of desalination water in domestic and industrial sectors as the best alternative. The proposed method has several advantages such as the management of heterogeneous scales of measurement without requiring any artificial transformation and the management of uncertainty by means of comparisons at a qualitative level in terms of the decision maker preferences. [ABSTRACT FROM AUTHOR]

Urban stormwater management is complex with diverse institutional responsibilities, imperfect regulation, and limited, often unclear accountabilities. Improving practices in that context requires strong leadership, long-term commitment, and lasting interorganizational relationships founded on trust. We summarize events that steered Melbourne’s waterway management authority to support a catchment-scale experiment markedly different from management applications or research approaches it had previously attempted. We highlight challenges, lessons learned, and subsequent institutional changes to stormwater management. Project challenges included: substantial investment in a small area from an organization with dispersed regional responsibilities, gaining intra- and interorganizational commitment, ongoing catchment development that counteracted management efforts, requirement for ongoing investment under short-term funding and political cycles, and absence of short-term measurable responses in stream health. These challenges led to design innovations, new catchment planning approaches, new best practice objectives, and new government policies that collectively changed approaches to stormwater management in our region. Critical to the initiation and success of this project, and probably to other similar projects, was building institutional commitment through long-term relationships between researchers and practitioners, and risk sharing made possible by co-investment. [ABSTRACT FROM AUTHOR]

The present study compares different legal texts on the quality of drinking water, the protection of surface waters and the establishment of drinking water protection areas in the European Union and selected countries in Latin America: Argentina, Brazil and Chile. In the context of a case study, carried out for the Argentine drinking water reservoir Paso de las Piedras, current management practice, its deficits in terms of catchment management practice and possible improvements are discussed based on the concept of water protection zones. The comparison of drinking water standards reveals that the regulations in the investigated Latin American countries comply with the standards of the Wold Health Organisation, while some differences are detected compared to the standards defined by the European Union (e.g., use of bulk parameters; individual standards). While within the European Union the definition and establishment of drinking water protection zones is a standard procedure, it is not explicitly suggested by national Latin American Laws. However, establishment of protection zones for drinking water reservoirs is feasible in accordance with water and environmental laws. The case study reveals that enforcement of the respective laws mostly fails. Protection zones are not implemented. Based on the findings, and according to European and German regulations on water protection zones, measures are suggested how to improve the raw water quality in the reservoir. Recommendations are provided for Latin American countries in general. [ABSTRACT FROM AUTHOR]

The promise of integrated research for addressing complex problems of sustainability such as catchment management has been widely recognised. However, the mechanisms for achieving integration in research have been the subject of few empirical studies. A major challenge of doing integrated research is how to combine and effectively manage diverse disciplinary perspectives and other knowledge/s in the generation of new knowledge for practice and policy change. We examined this challenge within a large catchment management research project in Australia's Murray Darling Basin and asked, ‘What supports or enables integration in research?’ Addressing this question requires an attention to integration as a dynamic process of knowledge production. We propose a model of this dynamic process which is characterised by a changing demand for integration in five different phases: (1) establishing the imperative for integration; (2) coordinating different disciplinary and other knowledge commitments; (3) consolidating arrangements for integration; (4) prioritising outputs from integration; and, (5) representing outputs of integration. For researchers and research managers this model can help identify the mechanisms required to support effective integration within research projects. We identify these mechanisms as sites and devices for integration that must be both planned (as part of the original integrated research design) and emergent (iteratively created and supported) in research projects. [ABSTRACT FROM AUTHOR]

Unpaved roads may induce adverse effects on downstream water resources by increasing suspended sediment concentration ( SSC). This study documents the localized impacts on stream SSC of six unpaved road-stream crossings in the rural Guabiroba River Catchment, in southern Brazil. Results demonstrated that SSC values downstream of road-stream crossings was between 3.5 and 10 times higher than upstream SSC at all third- and fourth-order stream locations. However, downstream values were statistically undistinguishable from those collected upstream of road-stream crossings at fifth-order sampling sites. These findings suggest that localized road effects on stream SSCs are scale-dependent in that these are important for low-order headwater streams yet undetectable for their higher order counterparts. Findings point to the importance of low-order stream crossings in increasing SSC and the need to further explore the role of unpaved roads as agents of water quality degradation in agriculturally active rural settings. [ABSTRACT FROM AUTHOR]

The Merguellil catchment (central Tunisia) is a typical Mediterranean semi-arid basin, which suffers from regular water shortage aggravated by current droughts. Over recent decades, the continuous construction of small and large dams and soil and water conservation works (i.e. contour ridges) have taken place within this watershed. However, little is known about the effect of these water-harvesting systems on the water balance components of arid or semi-arid basins. In this paper, we present the results of a study, which evaluates the impact of the contour ridges on water balance components and erosion at basin scale by using the soil and water assessment tool model ( SWAT). Large dams were modelled as reservoirs, small dams as ponds and contour ridges as potholes that fill with water and increase the percolation into the aquifer. The model predicts that contour ridges produce annually a reduction of 32 and 21% in surface run-off and river discharge, respectively, and an increase in aquifer recharge of 50%. At the same time, retention of a large proportion of entrained sediment (26%) was modelled. [ABSTRACT FROM AUTHOR]

Summary Annual total suspended solid (TSS) loads in the Mae Sa Catchment in northern Thailand, determined with an automated, turbidity-based monitoring approach, were approximately 62,000, 33,000, and 14,000 Mg during the three years of observation. These loads were equivalent to basin yields of 839 (603–1170), 445 (217–462), and 192 (108–222) Mg km −2 for the 74.16-km 2 catchment during 2006, 2007, and 2008, respectively. The yearly uncertainty ranges indicate our loads may be underestimated by 38–43% or overestimated by 28–33%. In determining the annual loads, discharge ( Q ) and turbidity ( T ) values were compared against 333 hand-sampled total suspended solid concentrations (TSS) measured during 18 runoff events and other flow conditions across the three-year period. Annual rainfall varied from 1632 to 1934 mm; and catchment runoff coefficients (annual runoff/annual rainfall) ranged from 0.25 to 0.41. Measured TSS ranged from 8 to 15,900 mg l −1 ; the low value was associated with dry-season base flow; the latter, a wet-season storm. Storm size and location played an important role in producing clockwise, anticlockwise, and complex hysteresis in the Q -TSS relationship. Turbidity alone was a good estimator for turbidity ranges of roughly 10–2800 NTU (or concentrations approximately 25–4000 mg l −1 ). However, owing to hysteresis and high sediment concentrations that surpass the detection limits of the turbidity sensor during many annual storms, TSS was estimated best using a complex multiple regression equation based on high/low ranges of turbidity and Q as independent variables. Turbidity was not a good predictor of TSS fractions >2000 μm. Hysteresis in the monthly Q -TSS relationship was generally clockwise over the course of the monsoon season, but infrequent large dry-season storms disrupted the pattern in some years. The large decrease in annual loads during the study was believed to be related to depletion of fine sediment delivered to the stream by several landslides occurring the year prior to the study. The study indicated the importance of monitoring Q and turbidity at fine resolutions (e.g., sub-hourly) to capture the TSS dynamics and to make accurate load estimations in this flashy headwater stream where hysteresis in the Q -TSS signature varied at several time scales. [ABSTRACT FROM AUTHOR]

Published data for temperate forests across the world are analyzed to investigate the potential for generalized quantitative expressions of catchment sediment yield impact in the years immediately following logging. Such generalizations would be useful in a variety of forestry and engineering tasks and would aid the spread of knowledge amongst both relevant professionals and new students. Data were assembled for paired catchment studies (51 catchments including 16 controls) that enabled the postlogging sediment yield impact to be compared with both the prelogging period and an undisturbed control catchment, using a specially defined relative response factor. Three categories of impact were derived: low-moderate, high, and very high, defined by specific ranges in the maximum value of the relative response factor. The maximum increase in specific sediment yield (in t km−2 yr−1) following logging is 1 order of magnitude above the control sediment yield at both the annual and storm event scales, at least under normal circumstances of Best Management Practice. There is no apparent relationship between sediment yield and the proportion of catchment logged, at least at the general scale. A cumulative probability distribution for the year in which the maximum postlogging sediment yield occurs, shows the majority of cases falling in the first 2 years. These generalizations refer to the broad response to logging as a function of ground disturbance, for example, by logging technique, roads, and burning. Although limited to order of magnitude quantification, they provide a basis for first estimates and for a general appreciation of an impact problem. [ABSTRACT FROM AUTHOR]

As an integrated result of many driving factors, significant declines in streamflow were observed in many rivers of the Loess Plateau (NW China). This can aggravate the inherent severe water shortages and threatens the regional development. Therefore, it is urgent to develop adaptive measures to regulate the water yield to ensure water security. A key step for successful implementation of such measures is to separate the response of water yield to the main driving factors of land management and climate change. In this study, the variation of annual streamflow, precipitation, potential evapotranspiration, and climatic water balance in a small catchment in the Loess Plateau (near Pingliang, Gansu province) was examined for over five decades, although the relative contribution of changes in land management and climate on the streamflow reduction were estimated. A statistically significant decreasing trend of -1.14 mm y-1 in annual streamflow was detected. Furthermore, an abrupt streamflow reduction because of construction of terraces and check-dams was identified around 1980. Remarkably, 74% of the total reduction in mean annual streamflow can be attributed to the soil conservation measures. Based on a literature review across the Loess Plateau, we found that the impact of changes in land management and climate on annual streamflow diminished with increasing catchment size. This means that there is a dependency on catchment size for the hydrological response to environmental change. This indicates that at least at the local scale well-considered land management may help ensure the water security at the Loess Plateau. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The protection of catchment areas for drinking water quality has become an increasingly disputed issue in Australia and internationally. This is particularly the case in regard to the growing demand for nature based and rural recreation. Currently the policy for the protection of drinking water in Western Australia is to enforce a 2 km exclusion zone with a much larger surrounding area with limited and prescribed access to recreators. The debate between recreators and water management agencies has been lively, culminating in a recent state government enquiry. This paper describes the second phase of a three phase study to develop a methodology for defensible policy formulation which accounts for the points of view of all stakeholders. We examine general community, active recreators and professionals' views on the current policy of catchment protection and five proposed alternatives using a social judgement theory approach. Key attitudinal determinants of the preferences for policies were identified. Overall the recreators did not support the current policy despite strong support from both the general community and the professional group. Nevertheless, it was evident that there was some support by the community for policies that would enable a slight relaxation of current recreational exclusion. It was also evident that there was a significant proportion of the general community who were dissatisfied with current recreational opportunities and that, in future, it may be less easy to police exclusion zones even if current policy is maintained. The potential for future integration of recreational and water source protection is discussed as well as the benefits of community research in understanding policy preferences in this regard. [Copyright &y& Elsevier]

To explore the value of high-frequency monitoring to characterise and explain riverine nutrient concentration dynamics, total phosphorus (TP), reactive phosphorus (RP), ammonium (NH-N) and nitrate (NO-N) concentrations were measured hourly over a 2-year period in the Duck River, in north-western Tasmania, Australia, draining a 369-km mixed land use catchment area. River discharge was observed at the same location and frequency, spanning a wide range of hydrological conditions. Nutrient concentrations changed rapidly and were higher than previously observed. Maximum nutrient concentrations were 2,577 μg L TP, 1,572 μg L RP, 972 μg L NH-N and 1,983 μg L NO-N, respectively. Different nutrient response patterns were evident at seasonal, individual event and diurnal time scales-patterns that had gone largely undetected in previous less frequent water quality sampling. Interpretation of these patterns in terms of nutrient source availability, mobilisation and delivery to the stream allowed the development of a conceptual model of catchment nutrient dynamics. Functional stages of nutrient release were identified for the Duck River catchment and were supported by a cluster analysis which confirmed the similarities and differences in nutrient responses caused by the sequence of hydrologic events: (1) a build-up of nutrients during periods with low hydrologic activity, (2) flushing of readily available nutrient sources at the onset of the high flow period, followed by (3) a switch from transport to supply limitation, (4) the accessibility of new nutrient sources with increasing catchment wetness and hydrologic connectivity and (5) high nutrient spikes occurring when new sources become available that are easily mobilised with quickly re-established hydrologic connectivity. Diurnal variations that could be influenced by riverine processes and/or localised point sources were also identified as part of stage (1) and during late recession of some of the winter high flow events. Illustrated by examples from the Duck River study, we demonstrate that the use of high-frequency monitoring to identify and characterise functional stages of catchment nutrient release is a constructive approach for informing and supporting catchment management and future nutrient monitoring strategies. [ABSTRACT FROM AUTHOR]

Abstract: Models and related analytical methods are critical tools for use in modern watershed management. A modeling approach for quantifying the source apportionment of dissolved nitrogen (DN) and associated tools for examining the sensitivity and uncertainty of the model estimates were assessed for the Sha He River (SHR) watershed in China. The Regional Nutrient Management model (ReNuMa) was used to infer the primary sources of DN in the SHR watershed. This model is based on the Generalized Watershed Loading Functions (GWLF) and the Net Anthropogenic Nutrient Input (NANI) framework, modified to improve the characterization of subsurface hydrology and septic system loads. Hydrochemical processes of the SHR watershed, including streamflow, DN load fluxes, and corresponding DN concentration responses, were simulated following calibrations against observations of streamflow and DN fluxes. Uncertainty analyses were conducted with a Monte Carlo analysis to vary model parameters for assessing the associated variations in model outputs. The model performed accurately at the watershed scale and provided estimates of monthly streamflows and nutrient loads as well as DN source apportionments. The simulations identified the dominant contribution of agricultural land use and significant monthly variations. These results provide valuable support for science-based watershed management decisions and indicate the utility of ReNuMa for such applications. [Copyright &y& Elsevier]

Abstract: Several attempts have been made to explain the formation of collaborative watershed partnerships—that is, multi-actor groups which work together to resolve environmental problems at a watershed scale. But to what extent do these explanations ‘travel’ from their original home – namely the USA – to other jurisdictions, where similar claims are being made about the rise of collaborative environmental governance? To that end, this article critically evaluates how well one leading theory, namely the political contracting framework (PCF), explains their emergence in the rather different institutional context of the United Kingdom. Drawing on a survey of collaborative watershed practices, it argues that they are functionally equivalent to partnerships. Furthermore, when suitably amended, the PCF explains many important aspects of their emergence. The same critical factors are associated with their development, but these should now be assessed across the entire ‘life-cycle’ of partnerships. The implications of these findings are identified and explored, the underlying aim being to inform a much more comparative theoretical approach to understanding what appear to be important changes in collaborative environmental governance practices. [Copyright &y& Elsevier]