Search

The COVID-19 pandemic affected nearly all strata of life, including scientific activities. Implementation of nationwide lockdowns, closures of universities, and other measures significantly limiting social mobility precluded field and laboratory research from being pursued at a pre-pandemic pace. On the other hand, working from home could translate into higher productivity of researchers in terms of publication output, ultimately affecting the journals' metrics. This effect has been well evidenced in the biomedical field, but whether it also occurred in aquatic sciences has not been explored. Therefore, this study aimed to analyze and compare various metrics of journals classified in the Scopus evaluations in 2019 (encompassing 2016–2019, the pre-pandemic period) and 2022 (covering 2019–2022, the pandemic period) within three subjects: aquatic science, oceanography, and water science and technology. In general, the number of journals classified into the considered categories increased in 2022 by 12%, and the majority (78%) experienced an increase in the CiteScore metric. The total published articles and received citations also significantly increased in 2022 by 17.5% and 63.5%, respectively, and were even higher in the case of open access journals—69% and 145%, respectively. The overall share of cited articles in the considered period was higher by 5% than in the 2019 Scopus evaluation and by 7% in the case of open access periodicals. However, source normalized impact per paper (SNIP) and the SCImago journal rank (SJR) values decreased by 7% and 8%, respectively. The highest share of citations was generated by Water Research, Water, and the Journal of Hydrology, and the highest number of articles was published by Water, Frontiers in Marine Science, and Desalination and Water Treatment. Only five of the COVID-19-related papers published in journals with the highest CiteScore and total number of citations received more than 200 citations, but their contribution to citations received by the journals was not high. In summary, the present study's findings indicate the high potential of the field dedicated to water sciences to adapt in a period challenged by an infectious disease pandemic. However, they do not exclude the adverse effect that this period could have on the activities of individual scientists and research teams. [ABSTRACT FROM AUTHOR]

Constraints to knowledge generation and dissemination are particularly acute in developing countries. Access to relevant sources of information for effective planning is often poor, and dissemination from research activities is weak. Indigenous research from developing countries rarely enters the global knowledge base, a situation which tends to further isolate these countries from current dynamic international debate on development research. In turn, this reduces the demand for, and thus the potential role of, national research programmes in helping define national and broader international policies on sustainable development, and on effective measures to achieve livelihood and food security targets. oneFish (http://www.onefish.org) is a Web based knowledge management system that contributes towards addressing this problem. oneFish draws together a broad cross section of stakeholders within the fisheries and aquatic research community. The primary aim of oneFish is to raise the profile of fisheries and aquatic research and reinforce its impact on responsible fisheries development. oneFish represents a fundamental advance in devolved management information systems. It responds to long sought-after information, communication and networking needs of many organisations engaged in promoting more responsive fisheries as well as aquatic resources research and development. The design of oneFish has been demand-led in that it integrates many of the communication ideas and needs articulated by these organisations into one interactive system. oneFish allows users to contribute information in electronic form to specific subject areas, and to search for and retrieve information, files and other linkages from the whole oneFish domain. Institutions and special interest groups are able to use oneFish to develop discussion groups and create virtual offices. Subject-specialist topic editors assist in the administration of specialised topics by editing and adding information submitted to them. The software underlying oneFish has been developed by Support Unit for International Fisheries and Aquatic Research (SIFAR) and the United Nations Food and Agricultural Organization (FAO). Since early 2000, a series of prototypes have been undergoing intensive testing with the co-operation of a small group of fisheries specialists. Version 1.0 of oneFish was released to the public in February/March 2001. The need to improve communication, information flow and networking in the field of fisheries and aquatic research and development has been widely recognised for a considerable time, and has been highlighted in all recent major international policy instruments related to fisheries development. It is recognised that the problem is particularly acute in developing countries where access to information relevant to effective research planning is often poor, and where dissemination from research activities is weak. Indigenous developing country research rarely enters the global knowledge base, a situation which tends to isolate these groups further from current dynamic international debate on development research. This in turn reduces the potential for effective collaboration and co-operation. Prerequisites for fisheries research achieving useful impact on sustainable development are active participation in debate and congruence between the knowledge systems of 'North' and 'South'. This enables both sides to recognise, learn and benefit from each other's rich knowledge. The relatively recent advent of Internet technologies offers a new opportunity to overcome this problem. In fact, the Internet has been rapidly assimilated in the 'North' rather than the 'South'. This has led to growing concern about its potential for widening the information gap- the so-called 'digital divide'. The problem is made even more difficult by the fact that infrastructures and abilities required are often inaccessible to the vast majority of people in developing countries. [ABSTRACT FROM AUTHOR]

The American eel (Anguilla rostrata) occupies a vast range in the West Atlantic Ocean and inflowing waters. Despite its presumed panmictic status, management of this species is geographically fragmented. There have been widespread calls for internationally coordinated efforts towards a range-wide stock assessment, but such an objective faces obstacles of a high degree of heterogeneity in major life history characteristics and the near-absence of such data in the northern, western, and southern parts of the species' range. This paper reviews novel and underutilized methods and data sources that may aid progress to an eventual range-wide assessment. Methods for obtaining information on distribution and abundance include mining of extant data and field surveys by glass bottom boat, electrofishing boat, net enclosures, environmental DNA (eDNA) and ocean larval tows. Analytic resources and tools include environmental databases, fetch as a covariate of abundance, accounting for the net effects of small ponds, GIS-oriented habitat modeling, glass eel-oriented population modeling, estimation of age structure from length structure, use of life history parameter clines to fill gaps in assessment input values, and life cycle modeling. eDNA is a cost-effective technique that has the potential to clarify American eel distribution, and possibly relative abundance, over the very large areas where data for this species are sparse. Most other techniques reviewed in this paper have substantial costs, which may constrain their use in the southern part of the American eel range where resources of aquatic science are often limited. [ABSTRACT FROM AUTHOR]

Ichthyofauna in the littoral zone the southern extremity of Lake Baikal was investigated. Modern data were obtained on fish composition in waters most affected by anthropogenic factors, where the probability of resultant changes in the fish community is highest. Long-term fish sampling was carried out in the zone of discharge and spread of wastes from Baikal Pulp and Paper Mill (BPPM); in regions near urban settlements; and near shore-protection construction operations. The data were compared with material previously collected, and with fish communities sampled in distant (control) areas. Variations in the composition of community are shown: some species that used to be absent were recorded in these areas, and possible reasons for their appearance are discussed. No distinct changes in the littoral fish were found attributable to anthropogenic influences. Recommendations on ichthyologic monitoring are proposed. [ABSTRACT FROM AUTHOR]

The Fishery Committee for the Eastern Central Atlantic (CECAF) seeks to promote the sustainable utilization of the living marine resources across the Eastern Central Atlantic between Cape Spartel and the Congo river through informed development of fisheries management actions. Aquatic Sciences and Fisheries Abstracts (ASFA) is contributing to the CECAF-PESCAO project “Improved Regional Fisheries Governance in Western Africa”, by developing a comprehensive inventory of marine fisheries research covering both primary literature (available online on both commercial and free to use platforms) and grey literature available at institutions holdings and not always accessible online. This assessment of fisheries management research in the region will enable CECAF, ASFA and, critically, member countries the means to access relevant contextual and discernible science-based materials and publications. Cataloguing and subsequent bibliometric analysis of large amounts of information specific to regional fisheries management will encourage solid research-based fisheries management recommendations at the national level by highlighting areas of fisheries management to investigate. This paper presents the preliminary results of the research inventory and bibliometric analysis, comparing the amount and type of information available in primary and grey literature collections for the region and at individual country level. [ABSTRACT FROM AUTHOR]

The Department of Botany on the Potchefstroom Campus (formerly Potchefstroom University for Christian Higher Education) of the North-West University (NWU) had its centenary in 2020. In this paper we celebrate this milestone by giving an overview of the history of the Department at this campus, including its recent establishment and expansion on the NWU Mahikeng Campus (formerly the University of North-West). A brief overview is presented of the advances in teaching and research over the years, and the development and relevance of the important plant collections in the botanical garden, two herbaria and the national diatom collection. The main emphasis of this contribution is, however, a reflection on the advancement and significance of research conducted by various disciplines on plant and algae function, diversity and ecological restoration over the years. The different disciplines in Botany at NWU, from the oldest to the more recent, are Plant Taxonomy, Plant Ecophysiology, Terrestrial Plant Ecology, Aquatic Sciences, Urban and Settlement Ecology, Geoecology, and Proteomics. Different aspects contributing to changes occurring in the environment, such as pollution, land degradation, urbanisation, overexploitation of resources and the subsequent effect of these on plant diversity and function are especially addressed in our current research. The results of our research inter alia led to solutions for problems occurring in the landscape and contribute to the well-being of the people using the land and water by restoring important ecosystem services. [ABSTRACT FROM AUTHOR]

The Department of Botany on the Potchefstroom Campus (formerly Potchefstroom University for Christian Higher Education) of the North-West University (NWU) had its centenary in 2020. In this paper we celebrate this milestone by giving an overview of the history of the Department at this campus, including its recent establishment and expansion on the NWU Mahikeng Campus (formerly the University of North-West). A brief overview is presented of the advances in teaching and research over the years, and the development and relevance of the important plant collections in the botanical garden, two herbaria and the national diatom collection. The main emphasis of this contribution is, however, a reflection on the advancement and significance of research conducted by various disciplines on plant and algae function, diversity and ecological restoration over the years. The different disciplines in Botany at NWU, from the oldest to the more recent, are Plant Taxonomy, Plant Ecophysiology, Terrestrial Plant Ecology, Aquatic Sciences, Urban and Settlement Ecology, Geoecology, and Proteomics. Different aspects contributing to changes occurring in the environment, such as pollution, land degradation, urbanisation, overexploitation of resources and the subsequent effect of these on plant diversity and function are especially addressed in our current research. The results of our research inter alia led to solutions for problems occurring in the landscape and contribute to the well-being of the people using the land and water by restoring important ecosystem services. [ABSTRACT FROM AUTHOR]

The I Journal of the American Water Resources Association i (JAWRA) is currently in its sixth decade of publication. Volume 53 of JAWRA, published in the year 2017, featured a series of papers focused on the application of the Soil Water Assessment Tool (SWAT) model developments and applications. The impact of this paper was strong and recognized by the Boggess Award as the outstanding paper published in JAWRA in the year 2018. [Extracted from the article]

This paper examines the performance of a semi-distributed hydrology model ( i.e., Soil and Water Assessment Tool [ SWAT]) using Sequential Uncertainty FItting ( SUFI-2), generalized likelihood uncertainty estimation ( GLUE), parameter solution (ParaSol), and particle swarm optimization ( PSO). We applied SWAT to the Waccamaw watershed, a shallow aquifer dominated Coastal Plain watershed in the Southeastern United States (U.S.). The model was calibrated (2003-2005) and validated (2006-2007) at two U.S. Geological Survey gaging stations, using significant parameters related to surface hydrology, hydrogeology, hydraulics, and physical properties. SWAT performed best during intervals with wet and normal antecedent conditions with varying sensitivity to effluent channel shape and characteristics. In addition, the calibration of all algorithms depended mostly on Manning's n-value for the tributary channels as the surface friction resistance factor to generate runoff. SUFI-2 and PSO simulated the same relative probability distribution tails to those observed at an upstream outlet, while all methods (except ParaSol) exhibited longer tails at a downstream outlet. The ParaSol model exhibited large skewness suggesting a global search algorithm was less capable of characterizing parameter uncertainty. Our findings provide insights regarding parameter sensitivity and uncertainty as well as modeling diagnostic analysis that can improve hydrologic theory and prediction in complex watersheds. Editor's note: This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series. [ABSTRACT FROM AUTHOR]

The quandong or native peach (Santalum acuminatum R.Br.) has been recognised as an important and tasty food resource among Aboriginal Australians in arid and semi-arid areas of southern Australia. It is valued for its fruit that is consumed raw or dried, and for its kernel, which is eaten raw or ground into paste for medicinal and skin care purposes. This paper reports on a study of ground stone implements within the Murray Darling Basin that has identified quandong stones as a distinct type of implement made specifically for the efficient cracking of quandong nuts. Data are presented on 1,327 ground stone implements from collections in 12 different locations in the Murray-Darling Basin (MDB), an area almost completely devoid of stone sources. Given the paucity of stone, multi-purpose use of implements is widely documented. Although it was common to find pits present in mortars and other ground stone tools demonstrating multiple functions, including use as anvils, a class of single purpose stones with multiple pits and distinctive form was identified. Most of these were found in areas known for groves of quandong and four were analysed for use-wear and residues along with two other ground stone items from the MDB. The results support their identification as specialised anvil stones for cracking quandong nuts. [ABSTRACT FROM AUTHOR]

Citizen science aquatic monitoring programs often rely on opportunistic, incidental contributions, which can lead to spatial bias, the uneven geographical distribution of sample sites. It is less known how this spatial bias compares to professional monitoring activities, or how geospatial biases (e.g. terrain slope, population density, road density) influence aquatic citizen science and professional lake monitoring programs. This paper compares sample sites in Ontario's volunteer Lake Partner Program, against those identified by a stratified random sampling method currently used by the Province of Ontario, Ministry of Natural Resources and Forestry. Exploration of spatial bias within each sampling method was conducted using Kernel Density Estimation, a nonparametric approach to interpolating the spatial trend of a given variable. Results indicate that two distinct patterns of sampling clusters exist between the two datasets, suggesting a 'cottage effect' in which volunteers are more likely to sample accessible locations associated with recreation and summer home ownership. Although professional monitoring programs are not exempt from spatial bias, our research suggests that citizen science lake monitoring programs in Ontario are more influenced by natural and demographic biases related to the location, accessibility, size and general attractiveness of lakes. [ABSTRACT FROM AUTHOR]

A prerequisite for an international fisheries agreement (IFA) to be stable is that parties expect the benefits from joining the agreement to exceed the benefits from free riding on the agreement, and parties only comply with the agreement as long as this is true. The agreement, therefore, implicitly builds on an expectation of the ecological condition of the natural resource. Game theoretical models often assume that all parties have the same (often perfect) information about the resource and that the exploitation is an equilibrium use of the stock. As stated by experts in natural science, the fish ecology still has many open questions, for example how to predict population dynamics, migration patterns, food availability, etc. In some cases, parties disagree about the state, abundance, and migration of a stock, which can reduce the possibilities of reaching an agreement for exploitation of the stock. This paper develops a model and applies it to the North-East Atlantic mackerel fishery, in order to analyze an IFA under different ecological scenarios, and also combines the model with the economic theory of entry deterrence. The model is used empirically to determine whether the parties with original access to the resource have an advantage when forming an agreement with a new party in having the ability to fish the stock down to a smaller size and thereby prevent another party from entering into the fishery. With a basis in entry deterrence, combined with lack of information, the paper illustrates the obstacles that have made an agreement for the North-East Atlantic mackerel so difficult to achieve. [ABSTRACT FROM AUTHOR]

Constructed wetlands are sustainable technologies for the treatment of wastewater. These biological systems have been widely studied throughout the world for more than 30 years; however, most studies have focused on the effects of design and engineering on pollutant removal from wastewater. Undoubtedly, agro-technical aspects have been given too little consideration by research. This paper reports the main results of a set of experiments carried out on two pilot horizontal subsurface flow systems in Sicily (Italy). Festuca, Lolium and Pennisetum spp. in combination and three emergent macrophytes–Arundo donax L., Cyperus alternifolius L. and Typha latifolia L.–alone, were assessed. The aim of the study was to demonstrate that, under predetermined hydraulic and design conditions, the choice of plant species and the management of the vegetation can significantly affect the pollutant removal performance of constructed wetlands. In addition, wastewater (after treatment) can also be used for agricultural purposes leading to increased sustainability in agricultural systems. Arundo and Typha-planted units performed better than Cyperus-planted units in terms of chemical, physical and microbiological contaminant removal. All the species adapted extremely well to wetland conditions. Polyculture systems were found to be more efficient than monocultures in the removal of dissolved organic compounds. The reuse of treated wastewater for the irrigation of open fields and horticultural crops led to significant savings in the use of freshwater and fertilizers. The results of physical-energy characterization of A. donax above-ground plant residues and pellets highlighted the fact that a constructed wetland could also be a potential source of bioenergy. [ABSTRACT FROM AUTHOR]

Sediment flushing can tackle reservoirs siltation and improve sediment flux through dammed rivers. However, the increase of the sediment loading below the dam can trigger a suite of undesired ecological effects in the downstream river reaches. To limit these drawbacks, sediment flushing can be controlled, by jointly regulating the sediment concentration of the evacuated water and the streamflow in the downstream channel. In this paper, we report on ten controlled sediment flushing operations (CSFOs), carried out between 2006 and 2012 in the central Italian Alps, at four hydropower reservoirs. These CSFOs displayed specific common traits: (i) Limits were set by the local environmental authorities concerning the allowable suspended sediment concentration. (ii) Reservoirs were fully drawn-down, earth-moving equipment was used to dislodge sediment, and the downstream water discharge was increased, compared to baseflow, by operating upstream intakes. (iii) Abiotic and biotic measurements in selected downstream reaches (before, during, and after the CSFOs) represented an integral part of the operations. In contrast, significant differences characterize the hydropower facilities (elevation and storage of reservoirs, in particular) as well as the basic CSFOs parameters (i.e., season, duration, mass and grain-size of the evacuated sediment, suspended sediment concentration). The macroinvertebrate assemblages resulted noticeably impacted by the CSFOs. In the short term, a significant density drop was observed, slightly influenced by the extent of the perturbation. In contrast, the latter appeared to control the assemblages contraction in terms of richness, according to the different sensitivity to sediment stress of the different taxa. The time employed to recover pre-CSFO standard ranged from few months to just under one year, and the related patterns would seem mostly correlated to the flushing season and to further site specificities. The density of trout populations was impacted as well, thus suggesting the adoption of mitigating strategies as removal by electrofishing before, and repopulation after the CSFO. [ABSTRACT FROM AUTHOR]

Freely-available satellite data streams and the ability to process these data on cloud-computing platforms such as Google Earth Engine have made frequent, large-scale landcover mapping at high resolution a real possibility. In this paper we apply these technologies, along with machine learning, to the mapping of peatlands–a landcover class that is critical for preserving biodiversity, helping to address climate change impacts, and providing ecosystem services, e.g., carbon storage–in the Boreal Forest Natural Region of Alberta, Canada. We outline a data-driven, scientific framework that: compiles large amounts of Earth observation data sets (radar, optical, and LiDAR); examines the extracted variables for suitability in peatland modelling; optimizes model parameterization; and finally, predicts peatland occurrence across a large boreal area (397, 958 km2) of Alberta at 10 m spatial resolution (equalling 3.9 billion pixels across Alberta). The resulting peatland occurrence model shows an accuracy of 87% and a kappa statistic of 0.57 when compared to our validation data set. Differentiating peatlands from mineral wetlands achieved an accuracy of 69% and kappa statistic of 0.37. This data-driven approach is applicable at large geopolitical scales (e.g., provincial, national) for wetland and landcover inventories that support long-term, responsible resource management. [ABSTRACT FROM AUTHOR]

The fragile ecological environment near mines provide advantageous conditions for the development of landslides. Mine landslide susceptibility mapping is of great importance for mine geo-environment control and restoration planning. In this paper, a total of 493 landslides in Shangli County, China were collected through historical landslide inventory. 16 spectral, geomorphic and hydrological predictive factors, mainly derived from Landsat 8 imagery and Global Digital Elevation Model (ASTER GDEM), were prepared initially for landslide susceptibility assessment. Predictive capability of these factors was evaluated by using the value of variance inflation factor and information gain ratio. Three models, namely artificial neural network (ANN), support vector machine (SVM) and information value model (IVM), were applied to assess the mine landslide sensitivity. The receiver operating characteristic curve (ROC) and rank probability score were used to validate and compare the comprehensive predictive capabilities of three models involving uncertainty. Results showed that ANN model achieved higher prediction capability, proving its advantage of solve nonlinear and complex problems. Comparing the estimated landslide susceptibility map with the ground-truth one, the high-prone area tends to be located in the middle area with multiple fault distributions and the steeply sloped hill. [ABSTRACT FROM AUTHOR]

This paper introduces this special issue of Aquatic Sciences. It outlines a multi-scale, hierarchical framework for developing process-based understanding of catchment to reach hydromorphology that can aid design and delivery of sustainable river management solutions. The framework was developed within the REFORM (REstoring rivers FOR effective catchment Management) project, funded by the European Union's FP7 Programme. Specific aspects of this 'REFORM framework' and some applications are presented in other papers in this special issue. The REFORM framework is founded on previous hierarchical frameworks, sixteen examples of which are reviewed. However, the REFORM framework has some particular properties that reflect the European context for which it was developed. The framework delineates regional landscapes into nested spatial units at catchment, landscape unit, segment, reach, geomorphic unit and finer scales. Reaches, regardless of their 'naturalness', are assigned to a river type based on valley confinement, planform and bed material. Indicators are quantified at each spatial scale to feed three groups of assessments. First, contemporary indicators at reach and geomorphic unit scales investigate present processes, forms and human pressures within each reach. These feed assessments of present reach hydromorphological function/alteration, including whether the reach is functioning appropriately for its type; riparian corridor function and alteration; and hydromorphological adjustment. Second, indicators at catchment to segment scales investigate water and sediment production and delivery to reaches and how these are affected by human pressures now and in the past. These are used to construct an inventory of changes over space and time. Third, historical reach and geomorphic unit scale indicators are used to construct the trajectory of reach-scale changes. Contemporary reach-scale assessments, space-time inventory, and trajectory of changes are then combined to establish how river reaches of different type, subject to different human pressures, and located in different environmental contexts behave in response to changes at all considered spatial scales. These support forecasts of the likely responses of reaches to future scenarios (e.g., changes in climate, land cover, channel interventions). [ABSTRACT FROM AUTHOR]

Summary Most often drought analysis methodologies are based on point-wise time series record assessments with very specific local conclusions, but their areal, regional and in general spatial properties are examined to a lesser extent. This paper will provide general description of droughts in addition to the regional methodological approaches with rather simple but innovative manner. The study area is thought as composed of a set of sub-areas each with different dry (wet) period probabilities. In general, heterogeneous region has different probability of dry(wet) spell occurrence at each sub-area. In fact, whenever the probability at each sub-area is not equal to any other sub-area, it corresponds to heterogeneous region. The areal cover probability (ACP) of the region is derived by considering the point-wise probabilities on the assumptions that the occurrences of dry (wet) spells are mutually exclusive, independent with heterogeneous probability patterns. Additionally extreme value probabilities of areal drought coverage are derived for heterogeneous sub-area probabilities. All of the heterogeneous drought probability expressions reduce down to homogeneous case provided that sub-areal probabilities are equal to each other. The methodology presented in this paper paves ways for more realistic drought phenomenon spatial probability of occurrences when the sub-areal dry spell probabilities are dependent on each other but heterogeneous. [ABSTRACT FROM AUTHOR]

Modeling has become the most commonly used method in fisheries science, with numerous types of models and approaches available today. The large variety of models and the overwhelming amount of scientific literature published yearly can make it difficult to effectively access and use the output of fisheries modeling publications. In particular, the underlying topic of an article cannot always be detected using keyword searches. As a consequence, identifying the developments and trends within fisheries modeling research can be challenging and time-consuming. This paper utilizes a machine learning algorithm to uncover hidden topics and subtopics from peer-reviewed fisheries modeling publications and identifies temporal trends using 22,236 full-text articles extracted from 13 top-tier fisheries journals from 1990 to 2016. Two modeling topics were discovered: estimation models (a topic that contains the idea of catch, effort, and abundance estimation) and stock assessment models (a topic on the assessment of the current state of a fishery and future projections of fish stock responses and management effects). The underlying modeling subtopics show a change in the research focus of modeling publications over the last 26 years. [ABSTRACT FROM AUTHOR]

Large-amplitude, horizontally-propagating internal wave trains are commonly observed in the coastal ocean, fjords and straits. They are long nonlinear waves and hence can be modelled by equations of the Korteweg-de Vries type. However, typically they propagate through regions of variable background hydrology and currents, and over variable bottom topography. Hence a variable-coefficient Korteweg-de Vries equation is needed to model these waves. Although this equation is now well-known and heavily used, a term representing non-conservative effects, arising from dissipative or forcing terms in the underlying basic state, has usually been omitted. In particular this term arises when the hydrology varies in the horizontal direction. Our purpose in this paper is to examine the possible significance of this term. This is achieved through analysis and numerical simulations, using both a two-layer fluid model and a re-examination of previous studies of some specific ocean cases. [ABSTRACT FROM AUTHOR]

Finding effective solutions to manage marine resources is high on political and conservation agendas worldwide. This is made more urgent by the rate of increase in the human population and concomitant resource pressures in coastal areas. This paper links empirical socio-economic data about perceptions of marine resource health to the breaking of marine management rules, using fisheries as a case study. The relationship between perceived rule-breaking (non-compliance with regulations controlling fishing) and perceived health of inshore marine environments was investigated through face-to-face interviews with 299 heads of households in three Tanzanian coastal communities in November and December 2011. Awareness of rules controlling fishing activity was high among all respondents. Fishers were able to describe more specific rules controlling fishing practices than non-fishers (t = 3.5, df = 297, p<0.01). Perceived breaking of fishing regulations was reported by nearly half of all respondents, saying “some” (32% of responses) or “most” (15% of responses) people break fishing rules. Ordinal regression modelling revealed a significant linkage (z = −3.44, p<0.001) in the relationship between respondents' perceptions of deteriorating marine health and their perception of increased rule-breaking. In this paper, inferences from an empirical study are used to identify and argue the potential for using perceptions of ecosystem health and level of rule-breaking as a means to guide management measures. When considering different management options (e.g. Marine Protected Areas), policy makers are advised to take account of and utilise likely egoistic or altruistic decision-making factors used by fishers to determine their marine activities. [ABSTRACT FROM AUTHOR]

The MERRA-2 atmospheric reanalysis product provides global, 1-hourly estimates of land surface conditions for 1980–present at ;50-km resolution. MERRA-2 uses observations-based precipitation to force the land (unlike its predecessor, MERRA). This paper evaluates MERRA-2 and MERRA land hydrology estimates, along with those of the land-only MERRA-Land and ERA-Interim/Land products, which also use observations-based precipitation. Overall, MERRA-2 land hydrology estimates are better than those of MERRA-Land and MERRA. A comparison against GRACE satellite observations of terrestrial water storage demonstrates clear improvements in MERRA-2 over MERRA in South America and Africa but also reflects known errors in the observations used to correct the MERRA-2 precipitation. Validation against in situ measurements from 220–320 stations in North America, Europe, and Australia shows that MERRA-2 and MERRA-Land have the highest surface and root zone soil moisture skill, slightly higher than that of ERA-Interim/Land and higher than that of MERRA (significantly for surface soil moisture). Snow amounts from MERRA-2 have lower bias and correlate better against reference data from the Canadian Meteorological Centre than do those of MERRA-Land and MERRA, with MERRA-2 skill roughly matching that of ERA-Interim/Land. Validation with MODIS satellite observations shows that MERRA-2 has a lower snow cover probability of detection and probability of false detection than MERRA, owing partly to MERRA-2's lower midwinter, midlatitude snow amounts and partly to MERRA-2's revised snow depletion curve parameter compared to MERRA. Finally, seasonal anomaly R values against naturalized stream flow measurements in the United States are, on balance, highest for MERRA-2 and ERA-Interim/Land, somewhat lower for MERRA-Land, and lower still for MERRA (significantly in four basins). [ABSTRACT FROM AUTHOR]

This opinion paper summarizes the results of an online survey on the role of experimental work in the hydrological sciences. The 20 survey questions covered various topics, such as advancements, needs, potentials and challenges in the hydrological sciences, and also touched on the issue of data sharing and data publication. A total of 336 hydrologists with both modelling and experimental backgrounds participated. [ABSTRACT FROM AUTHOR]

Marine science and numerical modeling (MASNUM) is widely used in forecasting ocean wave movement, through simulating the variation tendency of the ocean wave. Although efforts have been devoted to improve the performance of MASNUM from various aspects by existing work, there is still large space unexplored for further performance improvement. In this paper, we aim at improving the performance of propagation solver and data access during the simulation, in addition to the efficiency of output I/O and load balance. Our optimizations include several effective techniques such as the algorithm redesign, load distribution optimization, parallel I/O and data access optimization. The experimental results demonstrate that our approach achieves higher performance compared to the state-of-the-art work, about 3.5x speedup without degrading the prediction accuracy. In addition, the parameter sensitivity analysis shows our optimizations are effective under various topography resolutions and output frequencies. [ABSTRACT FROM AUTHOR]

The fishery for mobulid rays, also known as devil rays, has been practiced in the Bohol Sea for over a century yet very little is known about its history and characteristics. This study provides the first detailed description of the mobulid ray fishery in the Bohol Sea, Philippines. It describes the history and evolution of the fishery from the 19th century to 2013. It characterizes the fishery based on the species targeted, gears used, the organization, catch distribution, processing, monetary value, and the market of its by-products. This paper also analyses the changes that occurred through time, the management of the fishery and the drivers of the fishery. A multi-disciplinary approach was employed by combining ethno-historical research methods and catch landing monitoring in four primary sites within the Bohol Sea. This fishery began as an artisanal fishery using sail and row boats equipped with harpoons and gaff hooks practiced in at least four coastal villages in Bohol, Camiguin and Limasawa. The fishing fleet has decreased since the beginning of the 20th century however, with the motorization of the fishery and shift to the use of gillnets, the extent of the fishing grounds and market of the products have expanded. Four species of mobulid rays are caught in the Bohol Sea: Manta birostris, Mobula japanica, Mobula thurstoni and Mobula tarapacana. A fifth species, targeted by a fishing community off Dinagat as an off-shoot of the Bohol fishery is most likely the Manta alfredi. Currently, the fishery for mobulids is centered in Bohol Province where it has been practiced longest. The monetary value of mobulids in this region has increased and the dependence of fishing communities for their livelihood is significant. The unique characteristics of this fishery and the socio-cultural context within which it operates merits a thorough investigation in order to design the appropriate management strategy. [ABSTRACT FROM AUTHOR]

Aquatic research historically has focused on separate aquatic ecosystems (i.e., freshwater, estuarine, and marine). We argue that this separation into subdisciplines is artificial and may even be counterproductive. Instead, scientists should consider the physical linkages between different aquatic ecosystems and the many similarities in properties and processes among those ecosystems (conceptual linkages). The 4 papers in this J-NABS cluster demonstrate the value of integrating information from different aquatic ecosystems. For example, the papers illustrate that transformation and transportation of nutrients and energy physically and conceptually link all aquatic ecosystems and are facilitated by the characteristics of the medium that defines them all-- water. To promote the exchange of information within aquatic science, more interecosystem studies should be published in journals and books so that scientists will see parallels and linkages among freshwater, estuarine, and marine systems. Over the longer term, such studies would benefit from the funding and teaching of aquatic science as an integrated whole. [ABSTRACT FROM AUTHOR]

On the occasion of the 35th year from the publication of the first issue of the Proceedings of the Italian Association of Limnology and Oceanography (AIOL) we present here the results of a meta-analysis of all of the material included in the AIOL Proceedings, with the aim of analysing the last 30 years history of aquatic science in Italy as mirrored by the science presented by the AIOL members. The results of this meta-analysis were presented in September 2006 in Paris, on the occasion of the 100th anniversary of the 'Institut oceanographique, fondation Albert Ier, prince de Monaco'. We have screened the 17 volumes of the Proceedings and classified the articles into papers dealing with: (i) Biology and Ecology; (ii) Chemistry; (iii) Physics, and (iv) Geology, which represent the most relevant 'disciplines' of the AIOL. The articles were also classified as 'oceanographic' or 'limnological' papers, including all marine and freshwater aspects, respectively. Articles were finally classified on the basis of the environment where the studies were carried out: the water column or the benthic environment. The results of this analysis highlight the presence of wide fluctuations in the number of publications produced by the AIOL scientific community during more then three decades of the activity of the association in Italy. We also show that these fluctuations were associated with variable fluctuations in the availability of funding for aquatic research. The overall picture of the scientific outputs of the AIOL members as revealed by the analysis of the papers published on the AIOL Proceedings indicates that the Association had a fruitful activity during the last part of the past century, but experienced a major flaw during the first years of this century. Only in the last few years such activity restarted, thus giving rise to a possible new deal in the development of aquatic science in Italy. [ABSTRACT FROM AUTHOR]

Many investigations have been carried out in order to develop models which allow the linking of complex physical processes involved in urban flooding. The modelling of the interactions between overland flows on streets and flooding flows from rivers and sewer networks is one of the main objectives of recent and current research programs in hydraulics and urban hydrology. This paper outlines the original one-dimensional linking of heavy rainfall-runoff in urban areas and flooding flows from rivers and sewer networks under the RIVES project framework (Estimation of Scenario and Risks of Urban Floods). The first part of the paper highlights the capacity of Canoe software to simulate the street flows. In the second part, we show the original method of connection which enables the modelling of interactions between processes in urban flooding. Comparisons between simulated results and the results of Despotovic et al. or Gomez & Mur show a good agreement for the calibrated one-dimensional connection model. The connection operates likes a manhole with the orifice/weir coefficients used as calibration parameters. The influence of flooding flows from river was taken into account as a variable water depth boundary condition. [ABSTRACT FROM AUTHOR]

This paper draws on approaches in ecology, biology and policy analysis to examine the tensions between dams and fisheries in the Lower Mekong Basin. We review the exceptional importance of Mekong fisheries in terms of total catch, economic value and their role in rural livelihoods. The ecological conditions necessary to sustain the fish production are also analysed. The paper then considers the implications of dam development in the Mekong Basin, drawing on recent research to review predicted changes in hydrology and the resulting impacts on fishery resources. We then consider why, given the importance of fisheries, these potential impacts are not being addressed in regional policy processes. [ABSTRACT FROM AUTHOR]

A review of the literature published in 2007 on topics relating to lake and reservoir management is presented. This review, which covers more than 300 papers from more than 40 journals, focuses on topics directly related to the management of lakes and reservoirs. The journals with the most papers are Hydrobiologia, Journal of Great Lakes Research, Limnology and Oceanography, Water Research, and Water Resources Research. The review is divided into the following sections: Climate, Ecology, Eutrophication, Limnology, Mercury, Methods and Analytical Techniques, Modeling, Monitoring, Nutrients, Organic Matter, Planning and Management, Restoration and Treatment, Sediment, and Water Quality. [ABSTRACT FROM AUTHOR]

Abstract: Within hydrology performance criteria such as the Nash–Sutcliffe efficiency have been used to condition the parameter space of a model. Their use is motivated by the fact that the stochastic error series between a model output and corresponding observations is the result of the composite effect of multiple error sources which cannot be described, even in form, a priori. This paper formalises the use of such performance criteria within a Bayesian framework, such as Generalised Likelihood Uncertainty Estimation (GLUE), by introducing the concept of Informal Likelihoods. Informal Likelihoods are used to characterise desirable features in the relationship between the model output and corresponding observed data. A number of common performance criteria are considered as Informal Likelihoods. Analytical results and a simulation indicate all of the performance criteria considered as Informal Likelihoods in this paper have one or more properties which may be considered undesirable, but may perform no less well in conditioning model parameters than formal likelihoods for which the assumptions are only mildly incorrect. [Copyright &y& Elsevier]

This review of stream trout research literature for the 1987–2006 period covered >1300 papers dealing with 22 relevant topics, when compared with <400 papers on 18 topics in the previous one (1967–1986). The percentage of experimental approaches here quantified for both research reviews was 18% in the 1967–1976 period, increased to 21% in 1977–1986, to 39% in 1987–1996, and up to 43% in 1997–2006. Particular journals in the recent two decadal period published high percentages of experimental papers ( The Journal of Animal Ecology and Canadian Journal of Fisheries and Aquatic Sciences; 62.9% and 62.4%, respectively), others, intermediate percentages ( Nordic Journal of Fisheries Research, Transactions of the American Fisheries Society, North American Journal of Fisheries Management and Ecology of Freshwater Fish: 44.1%, 42.4%, 40.5%, and 35.6%, respectively); the remainder covered ≤33%. Research papers on stream ‘trouts’ published over the last two decades were classified into 22 subject areas for nine major journals separately and combined for 55 other journals. Subject areas dealing with the biology and ecology of trout redds, egg development, alevin emergence and onto fry and parr were the most heavily reported in nine major journals, as well as in all other journals combined. Habitat characteristics and cover use by trout were the next. Atlantic salmon and brown trout were the species with highest publication coverage in nearly all subject areas, with low coverage for all salvelinid (charr) species except brook charr. Research on Atlantic salmon in the UK used experimental approaches in nearly 60% of publications and in mid to high 30% for those on Atlantic salmon and brown trout in Scandinavian countries. Consideration is given to future research needs for stream trouts. [ABSTRACT FROM AUTHOR]

This paper presents an algorithm for generating stationary stochastic hydrologic time series at multiple sites. The ideas in this paper constitute a radical departure from commonly accepted methodologies. The approach relies on the recent advances in statistical science for simulating random variables with arbitrary marginal distributions and a given covariance structure, and on an algorithm for re-ordering the generated sub-sets of each synthetic year of data such that the annual auto-correlation of desired lag is maintained, along with the autocorrelations between the end of the preceding year and the beginning of the current year. The main features of the proposed algorithm are simplicity and ease of implementation. A numerical test is presented containing the generation of 1000 years of weekly stochastic series for four sites based on the 84 years of historical natural weekly flows from Southern Alberta in Canada. [ABSTRACT FROM AUTHOR]

Summary: This is the first of three related papers that summarizes streamflow characteristics of a set of 1221 global rivers. The rivers are well distributed world-wide, are un-impacted by upstream reservoirs or diversions for the period of data collection and have at least 10 years of continuous monthly and annual streamflow data. The following key features of annual flows are examined: mean, variability and skewness, distribution type (Gamma or Lognormal), flow percentiles and dependence. High and low frequency persistence is examined through the Empirical Mode Decomposition technique. Low flow run length, magnitude and severity are also explored, where severity is based on Extended Deficit Analysis. It has been observed elsewhere that there are large differences in hydrologic characteristics between Australia and southern Africa in contrast to the rest of the world. This issue is tested further in this paper. The range of analyses and results presented herein also form a suite of empirical evidence that future unified theories of hydrology at the catchment scale must be able to adequately describe. [Copyright &y& Elsevier]

Abstract: Extreme hydrological events are often triggered by exceptional co-variations of the relevant hydrometeorological processes and in particular by exceptional co-oscillations at various temporal scales. Wavelet and cross wavelet spectral analysis offers promising time-scale resolved analysis methods to detect and analyze such exceptional co-oscillations. This paper presents the state-of-the-art methods of wavelet spectral analysis, discusses related subtleties, potential pitfalls and recently developed solutions to overcome them and shows how wavelet spectral analysis, if combined to a rigorous significance test, can lead to reliable new insights into hydrometeorological processes for real-world applications. The presented methods are applied to detect potentially flood triggering situations in a high Alpine catchment for which a recent re-estimation of design floods encountered significant problems simulating the observed high flows. For this case study, wavelet spectral analysis of precipitation, temperature and discharge offers a powerful tool to help detecting potentially flood producing meteorological situations and to distinguish between different types of floods with respect to the prevailing critical hydrometeorological conditions. This opens very new perspectives for the analysis of model performances focusing on the occurrence and non-occurrence of different types of high flow events. Based on the obtained results, the paper summarizes important recommendations for future applications of wavelet spectral analysis in hydrology. [Copyright &y& Elsevier]

Summary: This paper deals with a non-standard application of frequency analysis of extremes of hydrologic variables in which some years of record are incomplete. If F(y) is the cumulative distribution function (cdf) of the extreme variable in a complete year (or ‘block’), the cdf of the variable in an incomplete year is taken as F(y) p , where 0< p <1 is the proportion of observations existing for that year. In this model, which can also take into account whether the missing observations occurred in the wet or dry season, the extreme values in different years no longer have the same parent distribution, so that where parameters of F(y) are estimated by maximum likelihood (ML), the usual large-sample characteristics of ML estimators (consistency, asymptotic Normality) may be modified. The paper examines the consistency, bias and approach to Normality of ML estimates of Gumbel parameters for position and scale, and of the Gumbel extreme event y 100 with 100-year return period. In the non-standard model F(y) p , consistency of ML estimates of Gumbel position and scale parameters is considerably modified, but the consistency of the estimated y 100 much less so. Estimates of y 100 are negatively biased, but the bias is similar to that found in the standard (no missing data) case. The results are relevant where hydrologic records are short and incomplete, such that all existing data must be fully utilized. [Copyright &y& Elsevier]

Summary: Stochastic generation of hydrological time series is a useful tool for the design and management of water resources systems. One of the shortcomings of many available models for stochastic generation of daily rainfall data is that they are unable to preserve satisfactorily key statistical properties simultaneously at daily, monthly and annual time scales. In this paper, a method for coupling two different time scales of stochastic hydrological time series models is introduced. The key feature of the method is to first generate two resembling time series, one preserving key statistical properties at a finer time scale and the other at a coarser time scale. Adjustment is then made to the finer time scale series so that this series becomes consistent with the coarser time scale series. Because the initial two time series resemble each other, the adjustment is kept small. In the paper, the technique for generating two resembling time series is described. The implementation of the method for coupling daily and monthly rainfall series is demonstrated. Test results of the method using rainfall data from a number of sites around Australia showed that the coupling method was able to generate daily rainfall time series that preserved satisfactorily some key statistical properties at daily, monthly and even annual time scales. [Copyright &y& Elsevier]

This paper describes the application of remotely sensed precipitation to the monitoring of floods in a region that regularly experiences extreme precipitation and flood events, often associated with cyclonic systems. Precipitation data, which are derived from spaceborne radar aboard the National Aeronautics and Space Administration's Tropical Rainfall Measuring Mission and from National Oceanic and Atmospheric Administration's infrared-based products, are used to monitor areas experiencing extreme precipitation events that are defined as exceedance of a daily mean areal average value of 50 mm over a catchment. The remotely sensed precipitation data are also ingested into a hydrologic model that is parameterized using spatially distributed elevation, soil, and land cover data sets that are available globally from remote sensing and in situ sources. The resulting stream- flow is classified as an extreme flood event when flow anomalies exceed 1.5 standard deviations above the short-term mean. In an application in the Limpopo basin, it is demonstrated that the use of satellite-derived precipitation allows for the identification of extreme precipitation and flood events, both in terms of relative intensity and spatial extent. The system is used by water authorities in Mozambique to proactively initiate independent flood hazard verification before generating flood warnings. The system also serves as a supplementary information source when in situ gauging systems are disrupted. This paper concludes that remotely sensed precipitation and derived products greatly enhance the ability of water managers in the Limpopo basin to monitor extreme flood events and provide at-risk communities with early warning information. [ABSTRACT FROM AUTHOR]

Abstract: A 27-month study of the water properties across the continental shelf off Perth, Western Australia (the “Hillarys Transect”), has provided the first systematic interdisciplinary climatology of the physical, chemical, optical and biological cycles across the shelf. This paper describes the main features of the seasonal and cross-shelf variability of the physical oceanography and chemistry, while companion papers discuss some of the links between the biology and physics of the region. The oceanography is dominated by the seasonally varying Leeuwin Current flowing southwards along the shelf break and outer shelf, and the northwards inshore Capes Current which is driven by the net southerly wind stress between about October and March (the austral summer). As a result of the poleward boundary current, there is no large-scale upwelling comparable with the Humboldt and Benguela Current systems. Water temperature and salinity in the shallow coastal waters are largely influenced by air–sea heat flux processes, while advection plays a more important role along the outer shelf; as a consequence, seasonal variations in the inshore temperature and salinity are much larger than those offshore. Cross-shelf exchange of water and plankton is effected by (1) large-scale meandering of the Leeuwin Current, (2) horizontal mixing as tongues of Leeuwin Current water penetrate across the shelf, (3) cascading of high-density coastal water offshore along the seabed and (4) sporadic summer upwelling onto the outer shelf (including the wake effect north of Rottnest Island). Nutrient and chlorophyll concentrations are low in comparison with other typical west coast situations. While there is some indication of a seasonal cycle, the relatively short sampling period and high patchiness have precluded definitive patterns being described and longer-term sampling may be required to resolve this. The effects of smaller-scale temperature and chlorophyll variability on satellite remote sensing measurements (both “within pixel” and “between pixel”) in these coastal waters have been quantified using the underway (horizontal) and profile (vertical) data from the surveys. The project has demonstrated the great potential of using remote sensing information for regular monitoring of the Western Australian continental shelf waters provided that adequate in situ validation measurements are also undertaken. [Copyright &y& Elsevier]

Abstract: Historical and modern scientific contexts are provided for the 2006 Binghamton Geomorphology Symposium on the Human Role in Changing Fluvial Systems. The 2006 symposium provides a synthesis of research concerned with human impacts on fluvial systems — including hydrologic and geomorphic changes to watersheds — while also commemorating the 50th anniversary of the 1955 Man''s Role in Changing the Face of the Earth Symposium [Thomas, Jr., W. L. (Ed.), 1956a. Man''s Role in Changing the Face of the Earth. Univ. Chicago Press, Chicago. 1193 pp]. This paper examines the 1955 symposium from the perspective of human impacts on rivers, reviews current inquiry on anthropogenic interactions in fluvial systems, and anticipates future directions in this field. Although the 1955 symposium did not have an explicit geomorphic focus, it set the stage for many subsequent anthropogeomorphic studies. The 1955 conference provided guidance to geomorphologists by recommending and practicing interdisciplinary scholarship, through the use of diverse methodologies applied at extensive temporal and geographical scales, and through its insistence on an integrated understanding of human interactions with nature. Since 1956, research on human impacts to fluvial systems has been influenced by fundamental changes in why the research is done, what is studied, how river studies are conducted, and who does the research. Rationales for river research are now driven to a greater degree by institutional needs, environmental regulations, and aquatic restoration. New techniques include a host of dating, spatial imaging, and ground measurement methods that can be coupled with analytical functions and digital models. These new methods have led to a greater understanding of channel change, variations across multiple temporal and spatial scales, and integrated watershed perspectives; all changes that are reflected by the papers in this volume. These new methods also bring a set of technical demands for the training of geomorphologists. The 2006 Binghamton Geomorphology Symposium complements the 1956 symposium by providing a more specific and updated view of river systems coupled with human interactions. The symposium focuses on linkages between human land use, structures, and channel modification with geomorphology, hydrology, and ecology. The emergence of sustainability as a central policy guideline in environmental management should generate greater interest in geomorphic perspectives, especially as they pertain to human activities. The lack of theories of anthropogeomorphic change, however, presents a challenge for the next generation of geomorphologists in this rapidly growing subfield. [Copyright &y& Elsevier]

Abstract: 234Th is an extremely useful radiotracer of particle dynamics in aquatic systems. Its utility, however, has yet to be realized by many within the aquatic science community. The reasons for this may in part be due to a lack of knowledge of how this nuclide has been used in the past as well as how and where 234Th might be profitably applied in future research. The purpose of this paper, then, is to examine the variety of 234Th applications that have been used to understand natural aquatic processes in four major areas: vertical transport, particle cycling, horizontal transport, and sediment dynamics. We provide a general overview of the possible applications of 234Th in the hopes of provoking an increased interest in the inherent potential and future application of 234Th in these systems. We end this paper with a discussion of future research avenues in the context of three specific regimes: (i) the upper 1000 m of the open ocean, (ii) coastal sediment/water processes and (iii) large freshwater lakes. [Copyright &y& Elsevier]

Abstract: Over the past few decades, the radioisotope pair of 238U/ 234Th has been widely and increasingly used to describe particle dynamics and particle export fluxes in a variety of aquatic systems. The present paper is one of five review articles dedicated to 234Th. It is focused on the models associated with 234Th whereas the companion papers (same issue) are focused on present and future methodologies and techniques (Rutgers van der Loeff et al.), C/ 234Th ratios (Buesseler et al.), 234Th speciation (Santschi et al.) and present and future applications of 234Th [Waples, J.T., Benitez-Nelson, C.R., Savoye, N., Rutgers van der Loeff, M., Baskaran, M., Gustafsson, Ö., this issue. An Introduction to the application and future use of 234Th in aquatic systems. Marine Chemistry, FATE special issue]. In this paper, we review current 234Th scavenging models and discuss the relative importance of the non-steady state and physical terms associated with the most commonly used model to estimate 234Th flux. Based on this discussion we recommend that for future work the use of models should be accompanied by a discussion of the effect that model and data uncertainty have on the model results. We also suggest that future field work incorporate repeat occupations of sample sites on time scales of 1–4 weeks in order to evaluate steady state versus non-steady state estimates of 234Th export, especially during high flux events (>ca. 800 dpm m−2 d−1). Finally, knowledge of the physical oceanography of the study area is essential, particularly in ocean margins and in areas of established upwelling (e.g., Equatorial Pacific). These suggestions will greatly enhance the application of 234Th as a tracer of particle dynamics and flux in more complicated regimes. [Copyright &y& Elsevier]

This paper focuses on the role of sensitivity analysis in studies of water transport in the environmental and geophysical sciences. Sensitivity analysis is useful in model development to determine how changes in parameter input will affect a model's response. It is also used in data assimilation to incorporate observations into a model. The adjoint method allows an efficient calculation of a model's sensitivity when the number of parameters exceeds the number of observations. In this paper we present studies demonstrating the use of the adjoint method for modelling water transport in both the Earth's crust and mantle. [ABSTRACT FROM AUTHOR]

In this paper hydrographic observations made over a fringing coral reef at the northern end of the Gulf of Aqaba near Eilat, Israel, are discussed. These data show exchange flows driven by the onshore–offshore temperature gradients that develop because shallow regions near shore experience larger temperature changes than do deeper regions offshore when subjected to the same rate of heating or cooling. Under heating conditions, the resulting vertically sheared exchange flow is offshore at the surface and onshore at depth, whereas when cooling dominates, the pattern is reversed. For summer conditions, heating and cooling are both important and a diurnally reversing exchange flow is observed. During winter conditions, heating occupies a relatively small fraction of the day, and only the cooling flow is observed. When scaled by ΔV, the observed profiles of the cross-shore during cooling velocity collapse onto a single curve. The value of ΔV depends on the convective velocity scale uf and the bottom slope β through the inertial scaling, ΔV ∼ β-1/3uf first proposed by Phillips in the 1960s as a model of buoyancy-driven flow in the Red Sea. However, it is found that turbulent stresses associated with the longshore tidal flows and unsteadiness due to the periodic nature of the buoyancy forcing can act to weaken the sheared exchange flow. Nonetheless, the measured exchange flow transport agrees well with previous field and laboratory work. The paper is concluded by noting that the “thermal siphon” observed on the Eilat reef may be a relatively generic feature of the nearshore physical oceanography of reefs and coastal oceans in general. [ABSTRACT FROM AUTHOR]

Abstract: A numerical model previously developed to systematically examine groundwater flow in vertical section near shallow surface water bodies such as lakes, wetlands and ponds is further developed to include simulation of the distribution patterns of hydrogeochemical and stable isotopic tracers in relation to the surface water body and the geometry of distribution patterns of the tracers in the groundwater release zone of the lake. Many different possible flow regimes are identified, however, in this paper attention is focused on flow-through water bodies, as these are the flow regimes observed in field validation. Two shallow lakes on the Swan Coastal Plain of south-west Western Australia are the subject of field studies where hydrogeochemical and stable isotopes are used to validate the flow-through groundwater flow regime predicted by the modelling confirming the validity of the approach. The flow regime transition diagrams introduced in earlier papers are extended to include consideration of the hydrogeochemical and stable isotopic indices ClL/Cl+ and (1000+δ L)/(1000+δ +). These ratios are introduced as an additional two of nine non-dimensional ratios that are necessary to analyse the problem. The ratios represent the chloride and isotopic composition (ClL and δ L), respectively, in the groundwater release zones of the lakes, relative to these parameters in the groundwater capture zone (Cl+ and δ +) for the lake. Field data from the case studies plotted on appropriately configured transition diagrams demonstrates the overall validity of the modelling approach and its underlying assumptions. It is concluded that isotopic and hydrogeochemical data are invaluable in interpreting the interaction between lakes or wetlands and regional aquifers as it is very difficult to make physical or hydraulic measurements in the field that allow an understanding of lake–aquifer interaction. The tools and concepts developed that are summarized in the presented transition diagrams are invaluable starting points for the consideration and analysis of other case-specific examples of groundwater–surface water interaction and will improve the scientific basis of decision-making concerning lake and wetland management and groundwater interaction by water resource and environmental managers. [Copyright &y& Elsevier]

Abstract: Conceptual hydrological modelling has under-utilised classical parameter analysis techniques (for both optimisation and uncertainty assessment) due to the prohibitively complicated nonsmooth geometry of typical parameter distributions. In the companion paper, a numerically robust model implementation framework was developed, based on stable time stepping schemes and careful threshold smoothing to eliminate the roughness of parameter surfaces. Here, this framework is exploited to enable parameter estimation using powerful and well-established techniques including: (i) Newton-type optimisation and (ii) principal-component-type (Hessian-based) uncertainty analysis. A case study using a representative rainfall-runoff-snow model illustrates the advantages of these previously unavailable methods, contrasting them with slower and less informative current approaches designed for nonsmooth functions. In addition to boosting the computational efficiency, the methods advocated in the paper yield more insight into improved model formulation and parameterisation (e.g., reducing model nonlinearity, detecting ill-conditioning and handling parameter multi-optimality). The impact of extreme model nonlinearity on model and parameter stability is also discussed, focusing on model identification aspects. [Copyright &y& Elsevier]

Abstract: The Model Parameter Estimation Experiment (MOPEX) is an international project aimed at developing enhanced techniques for the a priori estimation of parameters in hydrologic models and in land surface parameterization schemes of atmospheric models. The MOPEX science strategy involves three major steps: data preparation, a priori parameter estimation methodology development, and demonstration of parameter transferability. A comprehensive MOPEX database has been developed that contains historical hydrometeorological data and land surface characteristics data for many hydrologic basins in the United States (US) and in other countries. This database is being continuously expanded to include more basins in all parts of the world. A number of international MOPEX workshops have been convened to bring together interested hydrologists and land surface modelers from all over world to exchange knowledge and experience in developing a priori parameter estimation techniques. This paper describes the results from the second and third MOPEX workshops. The specific objective of these workshops is to examine the state of a priori parameter estimation techniques and how they can be potentially improved with observations from well-monitored hydrologic basins. Participants of the second and third MOPEX workshops were provided with data from 12 basins in the southeastern US and were asked to carry out a series of numerical experiments using a priori parameters as well as calibrated parameters developed for their respective hydrologic models. Different modeling groups carried out all the required experiments independently using eight different models, and the results from these models have been assembled for analysis in this paper. This paper presents an overview of the MOPEX experiment and its design. The main experimental results are analyzed. A key finding is that existing a priori parameter estimation procedures are problematic and need improvement. Significant improvement of these procedures may be achieved through model calibration of well-monitored hydrologic basins. This paper concludes with a discussion of the lessons learned, and points out further work and future strategy. [Copyright &y& Elsevier]

Abstract: This paper presents a new approach where a numerical quadrature scheme is applied to compute special functions described by integrals, appearing in many groundwater hydrology and pollution problems. The basic idea is to apply a smoothing procedure to the singular integrand and a non-linear coordinate transformation in the quadrature domain. Techniques for lowering the degree of singularity of integrand functions have been successfully applied in physics and computational mechanics, and the self-adaptive co-ordinate transformation used in this work is a well-established procedure in general boundary element integrals quadrature. The main advantage of this joint technique is that it can be directly used to other related functions without further approximations and the user can choose freely the degree of accuracy. Tables included in this paper show the improvement of several orders of magnitude when both techniques are applied simultaneously. [Copyright &y& Elsevier]

Abstract: Grass swales and filter strips are among the simplest and most cost-effective form of stormwater control measures. Despite this, relatively few controlled studies have been undertaken to assess their performance, and very few models are available to predict their efficiency. This paper focuses on field performance of grass filters in removal of total suspended solids (TSS) from overland flow, and verification of TRAVA, a model of sediment behaviour in grass filters (published earlier in Deletic, A., 2001. Modelling of water and sediment transport over grassed areas. Journal of Hydrology 248, 168–182; Deletic, A., 2005. Sediment behaviour in runoff over grassed surfaces. Journal of Hydrology 301, 108–122). Limited nutrient removal data were collected, at one of the field sites. The paper presents results from controlled field tests undertaken on a grass filter strip in Aberdeen, Scotland, and a grass swale in Brisbane, Australia. In both studies TSS concentrations were recorded along the grass, for artificial inflow of water and sediment of different flow rates and sediment concentrations. In the Aberdeen study the emphasis was on performance in relation to different sediment particle sizes, while for the Brisbane swale, treatment performance for total nitrogen (TN), and total phosphorus (TP) were also recorded. Both experimental programmes had an unsteady input of pollutants. The Aberdeen strip reduced sediment inflow concentrations by 61–86%, whilst the Brisbane swale removed an average of 69, 46, and 56% of the total loads of TSS, TP and TN, respectively. TRAVA was used to model both the strip and swale. For the Aberdeen strip, the differences between the measured and modelled sediment loading rates were within ±25% of measured. Modelled concentrations in outflow from the Brisbane swale were within ±17% of measured. The predicted mass of total sediment removed during experiments was within ±50% of measured for the Aberdeen strip and ±11% for the Brisbane swale. TRAVA is therefore shown to be a reliable tool for prediction of the performance of grass filters used for stormwater treatment. [Copyright &y& Elsevier]

The aim of this paper is to compare two views of flood management and thus add to the present thinking of living with floods as opposed to the traditional approach of flood control. The traditional pathway has widely been adopted in developed countries and aims to control floodwaters by means of dams and dikes. The alternative pathway tends towards a policy whereby society lives with the floods by being prepared and having the right damage reduction measures in place. In this paper two pathways are tentatively compared for the Lower Incomati Basin, Mozambique. In the design cultural theory is considered, as is how the design of each path may look according to different management perspectives. The Lower Incomati Basin provides an interesting case study as it is in a relatively undeveloped state. Hence, it is an ideal area for conducting research into the application of alternative flood management strategies. The preliminary results suggest that both pathways are feasible. However, considering recent hydrological extremes such as the 2000 floods, the resilient pathway may ultimately be a more appealing flood management strategy. [ABSTRACT FROM AUTHOR]