Search

This article discusses the governance aspects of managing river, lake, and aquifer basins, both at the transboundary and domestic levels. It highlights the importance of basin organizations in facilitating negotiation, data sharing, and decision-making among stakeholders. The article also explores the challenges faced by international basin organizations, such as power asymmetries and the inclusion of non-state actors. Additionally, it examines the scale implications of transboundary agreements and the participation of civil society in water management. The article concludes by emphasizing the need for improved institutions and cooperation in order to effectively manage water resources. [Extracted from the article]

The river health evaluation is typically complex non-linear system with characteristics of fuzziness and randomness. However, conventional gray clustering method has difficult to effectively describe fuzzy and random information simultaneously. For this purpose, the cloud model and fuzzy entropy theory are introduced to establish 2D gray cloud clustering-fuzzy entropy comprehensive evaluation model. Different with health level models, it reflects river health situation from aspects of health level and corresponding water body complexity simultaneously. The health level is obtained by gray cloud whitened weight function (first sub-system) and fuzzy entropy represents complexity and fuzziness of river health situation (second sub-system). Moreover, multi-level river health evaluation indicator system is constructed with dividing indicators into common and distinct sections according to differences on river characteristics. Meanwhile, indicator weights are determined by renewed combined weighting method based on minimum deviation principle. Finally, we conduct health evaluation work for rivers in the Taihu basin. The evaluation health levels and fuzzy entropy for river A–G are H3 (0.4888, relatively significant); H2 (0.5476, relatively fuzzy); H2 (0.7526, fuzzy); H2 (0.4731, relatively significant); H2 (05138, relatively fuzzy); H3 (0.5822, relatively fuzzy), and H2 (0.4064, relatively significant), respectively. Results are consistent with current river health situation and more intuitive than compared models. Furthermore, evaluation results with four different weighting methods are compared to further demonstrate rationality of the weighting method and evaluation model. Hence, the model proposed is demonstrated to provide new insight for solving river health assessment problem effectively. [ABSTRACT FROM AUTHOR]

Multivariate spatial patterns of 38 environmental variables (habitat metrics, metals, pyrethroids and sediment characteristics) and 14 benthic metrics were determined from over a decade of sampling in five California waterbodies. Canonical discriminant analyses produced very highly significant separations of the five watersheds based on environmental variables. The discriminant analyses based on benthic metrics also produced highly significant separations, although confidence ellipses were not quite as well separated as the environmental variables. Separation of creeks made ecological sense as Pleasant Grove Creek (PGC), which appeared to have greater habitat quality also had benthic metrics indicative of less stressed benthic communities, while the Santa Maria River watershed (SM) appeared to have lower habitat quality and more toxicants in the sediments also appeared to have benthic communities indicative of stress-tolerant taxa. The benthic community health of the other three creeks (Arcade Creek [ARC], Kirker Creek [KC] and Salinas Streams [SAL]) were considered intermediate in apparent stress between PGC and SM. Overall, benthic communities were somewhat more similar between creeks than were the environmental conditions. Benthic communities have greater overlap in characteristics than would be expected from environmental conditions, perhaps due to a greater resilience since they are generally dominated by tolerant benthic taxa. [ABSTRACT FROM AUTHOR]

Research at the interface between terrestrial, riverine, estuarine and marine environments is frequently constrained by significant disciplinary and geographical boundaries. This article outlines an international initiative, DANUBIUS-RI, which aims to address these problems by facilitating biogeochemical monitoring and interdisciplinary research on river-sea systems. The scope of the project spans the environmental, social and economic sciences and was accepted into the European Strategy Forum on Research Infrastructures roadmap in 2016. When operational, DANUBIUS-RI will offer researchers access to interdisciplinary expertise, facilities and European river-sea systems, providing a comprehensive platform for multidisciplinary research and training. [ABSTRACT FROM AUTHOR]

Airborne lidar bathymetry (ALB) is an effective advanced technology for mapping and measuring water depth in shallow water coastal zones as well as inland freshwater bodies such as rivers and lakes. The ability of light beams to detect and traverse shallow water columns has provided valuable information about unmapped and often poorly understood coastal and inland waterbodies. ALB surveys require specific best practices and quality management procedures to provide the highest-quality end product. Implementing quality assurance procedures before the survey commences and frequent quality control checks during and after the survey are essential steps. In this article, we summarize overall ALB development history, discuss specific ALB requirements, and provide examples that reflect our experiences of the Leica Chiroptera ALB system. Supplemental surveys,in situmeasurements, and developing in-house algorithms are all beneficial and have the means to increase confidence and versatility of lidar bathymetry. [ABSTRACT FROM PUBLISHER]

This paper examines the potential for multiple co-benefits to arise through re-establishing the connection between Aboriginal people and their lands. The research project was participatory in its design and implementation, and centred on three short but intensive visits to the Kendall River over a period of 4 years. Interviews with and observations of Kendall River people on country provided qualitative information concerning their wish to reconnect with country, not only to transmit key cultural knowledge through the generations, re-socialise their lands and manage them appropriately but also to help them manage the negative consequences of Wik aggregation in the troubled community of Aurukun. Participants reported that returning to and carrying out activities on country, and the family and country planning resulting from those trips, provided a way to counter feelings of disempowerment and despondency arising from living solely in Aurukun. This paper concludes by arguing that activities that re-engage Aboriginal people with country (if not actually returning to live on country) can serve to build cultural resilience in the face of multiple economic, environmental and social challenges, including those arising from life lived largely in communities such as Aurukun, thereby also likely benefiting their physical and psychosocial health and well-being. [ABSTRACT FROM AUTHOR]

Suspended solids are present in every river, but high quantities can worsen the ecological conditions of streams; therefore, effective monitoring and analysis of this hydrological variable are necessary. Frequency, seasonality, inter-correlation, extreme events, trends and lag analyses were carried out for peaks of suspended sediment concentration (SSC) and discharge (Q) data from Slovenian streams using officially monitored data from 1955 to 2006 that were made available by the Slovenian Environment Agency. In total more than 500 station-years of daily Q and SSC data were used. No uniform (positive or negative) trend was found in the SSC series; however, all the statistically significant trends were decreasing. No generalization is possible for the best fit distribution function. A seasonality analysis showed that most of the SSC peaks occurred in the summer (short-term intense convective precipitation produced by thunderstorms) and in the autumn (prolonged frontal precipitation). Correlations between Q and SSC values were generally relatively small (Pearson correlation coefficient values from 0.05 to 0.59), which means that the often applied Q–SSC curves should be used with caution when estimating annual suspended sediment loads. On average, flood peak Q occurred after the corresponding SSC peak (clockwise-positive hysteresis loops), but the average lag time was rather small (less than 1 day). Editor M.C. Acreman; Associate editor Y. Gyasi-Agyei [ABSTRACT FROM AUTHOR]

A new approach, the ‘Naturalness Status' (NS), is suggested to classify the hydrologic alteration of temporary rivers from natural conditions based on the Hydrological Status Tool (HS-Tool). The HS-Tool considers two metrics: the degree and the predictability of dry flow conditions for both natural flow and its alterations, at each water body in actual and natural conditions. The Soil and Water Assessment Tool (SWAT) model is simulating the river flow of Evrotas water bodies, Greece, under natural, actual and climate-impacted conditions. The majority of Evrotas water bodies (72%) experience good (low-impacted) NS for the examined period (1990–2010), despite their intermittent flow regime. Severe flow alteration is predicted for 57% of Evrotas water bodies (high-impacted NS), while selecting the KNMI-RACMO2 future climate projections scenario (2020–2060) as input into the SWAT model. Hydrologic extreme drought phenomena or anthropogenic pressures in water regime can be quantified by the NS. The method is intended to be used in basin decision-making analysis at fulfilling the Water Framework Directive goals. [ABSTRACT FROM PUBLISHER]

The legal literature concerning the interplay between innovation and law is split between two streams: law and economics (broadly defined) and law and technology. They seem to exist in parallel and largely nonintersecting inter-disciplinary silos. This paper attempts to reconcile these two streams and identify synergies. Even the definition of innovation needs to be recast in order to integrate both streams: it is best seen as a combination of three elements, namely (i) an invention, (ii) which is diffused and adopted and (iii) which has a positive social impact. One of the main shortcomings of law and technology lies in how it sees innovation as an essentially technological phenomenon, and one that is largely exogenous to the regulatory process. Law and economics literature pays closer attention to regulation for innovation (or innovativeness): it identifies market failures, such as market power, and externalities flowing from the public good nature of information. Yet law and economics literature assumes that innovation is good for welfare, without more. Law and technology can usefully help to make up for that flaw; it takes a more critical view of innovation and is rather concerned with the regulation of innovation. The vexed issue of disconnect -- the difficulty for law to keep up with the pace of innovation -- shows how these two streams can be combined. Within regulatory disconnect, one can distinguish a horizontal dimension (time) and a vertical dimension (level of generality). Much law and technology literature advocates early and technology-specific intervention to deal with emerging innovations. Law and economics literature would point in the other direction on both dimensions, but beyond that, it also offers insights into institutional models that allow a balancing of the concerns arising from each stream of literature, using independent and accountable regulatory authorities. [ABSTRACT FROM AUTHOR]

Efforts at the restoration of river ecosystems are needed not only in local habitats but are also important in terrestrial regions. Large-scale assessment of human activities can be useful in integrated watershed management. In this study, we modified the Ecological Risk Index (ERI) by considering the spatial distribution of human activities in China's Haihe River Basin (HRB). The stressor factors of human activities included population, impervious surface, cattle, agricultural land use, industry, fertilizers, pesticides, water conservation facilities, and roads. A total of 423 assessment units in the HRB were created by combining watershed and administrative boundaries to analyze the spatial distribution of human activities. Two index options, the ERI (including all stressors) and the ERI-D (excluding reservoirs and sluices), were examined for different management objectives. All the stressors and both ecological risk indices (ERI and ERI-D) were ranked in four levels: low, moderate, high, and very high. Our study demonstrated that the ERI and ERI-D can provide an overview of the spatial pattern of human stressors related to river ecosystems across a large geographic region. The approach developed in this study is useful for prioritizing management actions in targeted areas. [ABSTRACT FROM AUTHOR]

We review the severe water-management problems of the Nile Basin, where physical water scarcity is associated with high demographic growth, leading to a sharply rising demand for competing water uses such as hydropower and large-scale irrigation. Rapid economic growth is perceived as the means to emerge from the poverty trap that afflicts livelihoods in the Upper Basin and vital wetland ecosystem services such as fish biomass, freshwater biodiversity, groundwater recharge, flow regulation and local climate moderation are threatened by the water-development schemes and pollution that follow from this policy. Their cumulative impacts remain unaddressed. The High Aswan Dam's impacts on freshwater biodiversity are incompletely understood; a significant number of species may have become threatened as a result of its construction. Today the reservoir water quality is high, it is thought to support 47 fish species, its local human activities are restricted by central government regulations and recent estimates indicate that eutrophication threats are unlikely. Sediment and nutrient inputs coming into it from upstream will, however, continue to decrease in the near future as a result of newly built and planned dams in the upper basin. The dams will also reduce discharge and cause further loss of connectivity between the river and its floodplain, exacerbated by the possible completion of the Jonglei Canal bypassing the Sudd swamps. These impacts will affect the Nile's vulnerable aquatic biodiversity and regulatory services that are likely to affect local climate conditions. Under the current geopolitical scenario, management decisions that could favour participatory and sustainable options are over-ruled by high-level political trade-offs between the numerous riparian states. The financing of major hydropower developments by vested interests creates a scenario that is unlikely to favour sustainable resource management and conflict resolution. [ABSTRACT FROM PUBLISHER]

Emissions of nitrous oxide (N2O) from aquatic systems such as rivers and estuaries are enhanced as a result of human activities on land resulting in enhanced nitrogen availability in aquatic systems. These human activities include agricultural activities such as fertilizer use, as well as industrial activities resulting in nitrogen (N) losses to the environment. In this article, we analyze past and future trends in global emissions of N2O from rivers and estuaries. We calculate aquatic N2O emissions from trends in the export of nitrogen to coastal waters by world-wide rivers. These trends in riverine N exports are from the Global NEWS models, which are global, regionally explicit models developed in the NEWS (Nutrient Export from WaterShed) framework. The NEWS models calculate nutrient exports from land to coastal waters, taking into account different human activities on the land, as well as biological N2 fixation and different ways in which nitrogen is retained in watersheds, including the effect of dams. We present global total emissions of N2O for the years 1970, 2000, and for four scenarios for 2050, as well as regional patterns. [ABSTRACT FROM AUTHOR]

Coupled hillslope and channel processes in headwater streams (HWS) lead to rapid changes in channel dimensions. Changes in channel size and shape caused by a debris flow event along the length of a headwater stream in the Ashio Mountains, Japan, were captured with the aid of repeat high-definition surveys using terrestrial laser scanning (TLS) techniques. The HWS was classified into three distinct reaches below the debris flow initiation zone. A large knickpoint separated an upper bedrock reach from a colluvial reach along the midsection of the drainage. The colluvial reach transitioned to a lower bedrock reach that terminated at the master stream. Cross-sectional and morphometric analyses revealed no statistically significant changes in channel size or shape along the upper bedrock reach. Debris flow erosion generated significant differences in channel size and shape along a colluvial reach. Sediment bulking associated with erosion along the colluvial reach led to increases in channel size along the lower bedrock reach, but no statistical differences in channel shape. Morphometric analyses from the TLS point cloud revealed that debris flow erosion produced a distinct nonlinear change in channel dimensions in the downstream direction within the HWS. Variations in channel substrate along the length of HWS contributed directly to this nonlinear response. The episodic nature and nonlinearity of erosion associated with the current debris flow event highlights the importance of debris flows in general in understanding the transport of sediment, coarse to fine particulate organic material, and large woody debris, which are critical to the long-term management of riverine environments. TLS sampling methods show promise as one component of a multianalytical approach needed to continuously monitor and manage the dynamics of HWS. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) sources in Louisiana Rivers and coastal environments were characterized using principal components analysis (PCA). Distinctive clustering revealed petrogenic, pyrogenic, and biogenic/diagenetic origins of the PAHs. PCA included data from analysis of 478 samples selected from a pool of 3,540 samples for which the sum of 34 alkylated and non-alkylated PAHs and petroleum biomarker compounds, determined by gas chromatography/mass spectrometry, exceeded 1 μ gg-1. Additionally, 21 reference PAHs profiles of known origin and multiple analyses of South Louisiana crude oil during a 3-year period were included in the PCA analysis. PCA clusters differentiated petrogenic PAHs derived from fresh to extremely weathered oil spills. Multiple sources of PAHs were discernable from petrogenic, pyrogenic, or diagenetic sources. This study demonstrated the utility of PCA tools in environmental forensics and source fingerprinting analysis to identify prime suspects of PAHs pollution in the environment. [ABSTRACT FROM AUTHOR]

Seven family-level metrics were determined from benthic macroinvertebrate samples collected monthly across four different landuse sites in the Cazenovia Creek watershed in western New York. We evaluated which metrics were most appropriate for, and effective in, discerning differences among the sites. Dramatic and consistent seasonal differences in metric scores were observed across all sites. All metric scores indicated markedly better biological health during winter months than during summer months. The biological impairment designation was highest in the summer at the suburban and agricultural sites. Coefficients of variation were considerably greater at the lower stream order sites. The metrics that were most appropriate and effective in assessing benthic assemblage health in this study were: richness, percent model affinity, family-level biotic index, and Ephemeroptera-Plecoptera-Trichoptera index. These indices correlated with a low amount of redundancy in a Pearson matrix, had significant discriminatory power in assessing biological impairments across sites, and had low variation within sites and seasons. This suggests these metrics should be selected for bioassessments in similar Great Lakes watersheds. [ABSTRACT FROM AUTHOR]

The relative influence of water regime and other environmental factors on the organization of benthic macroinvertebrates was studied over three years in a small intermittent river basin (River Pula) in Sardinia. The intermittent nature of the led to high spatial and temporal variability of abiotic characteristics. Twenty-eight invertebrate taxa accounted for 90% of the sampled individuals; and of there four (Chironominae, Caenis luctuosa, Diamesinae) Protonemura ichnusae) accounted for more than 50% of the total density. Canonical correspondence analysis showed that 34.6% of the biological variance was accounted for by abiotic factors and that different environmental features, including sediment structure and stream order, had a larger influence on benthic macroinvertebrate distribution and abundance than the intermittent water regime, even though local drought events completely disrupted the macroinvertebrate community. [ABSTRACT FROM AUTHOR]

The flow over a drop structure placed in a rectangular channel was investigated tnrough an experimental program. It was noted that the downstream depth of flow was crucial to the formulation of the problem. Two procedures were developed for the estimation of the downstream depth. The first procedure was physically based with an empirical component for the estimation of the depth of the pool formed at the base of the drop. The second was a purely empirical procedure, which resulted in an equation for the direct estimation of the downstream depth. The parameters of the equation were determined by least-squares techniques. Both' procedures resulted in reasonably accurate estimates of the downstream depth. The energy loss at the drop was then calculated and compared with the results of previous studies. The investigations were repeated with a single step placed at the base of the drop. It was observed that the step significantly increased the energy loss at the drop. [ABSTRACT FROM AUTHOR]

Rapid changes in the lower Salt River, a tributary to the Knysna estuary, southern Cape, is documented through the use of an air photo time series. The evidence plotted for the flood plain and estuary, over the period 1936-1998, demonstrates rapid changes in the channel course, the loss of an extensive Phragmites australis bed and siltation of the estuary. Land use changes in two western catchments particularly impacted on the hydrology. The validity of local oral evidence is confirmed. The floods in 1996 exacerbated siltation by impacting on a development in the upper Simola catchment. Sedimentation in the estuary was greater than previously recorded. The presence of coversand on interfluves and valley heads renders the entire catchment, an area of landscape sensitivity, susceptible to rapid change. [ABSTRACT FROM AUTHOR]

Studies the initiation and expansion of gullies in the Buasono area of Lesotho. Factors that affect gully initiation and development; Rate of extension which increases with the increasing amount and intensity of rainfall.

The Mfolozi Estuary situated in northern KwaZulu-Natal, South Africa is a shallow, micro-tidal estuary with average depths of less than 1.5 m during mean flow conditions. During low flow conditions, a combination of sedimentation processes, including longshore drift, tidal and aeolian transport, leads to a rapid reduction in the width, and a northerly migration of the estuary mouth. The result is a reduction in the tidal prism affecting the estuary, and tidal ranges at the mouth drop sharply and conditions in the estuary become lagoonal. On the other hand, seasonal high fluvial flows and major floods cause breaching of the sand barrier, creating a new mouth inlet with major changes in estuarine dynamics and morphology. The short term observed transitional changes between estuarine and lagoonal conditions are outlined in relation to long term historical evidence of spatial and temporal variation in the Mfolozi system so as to qualify the dominant forcing processes controlling the morphodynamics. [ABSTRACT FROM AUTHOR]