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The article reflects on a paper presented at the American Water Resources Association's (AWRA) 1974 conference related to groundwater hydrology. Topics discussed include the move of groundwater hydrology from qualitative to quantitative analysis, the advances in geophysics and geochemistry, and the inclusion of ground-water studies. Also provided is information about the application of research to several professionals including consulting engineers, city planners, and well drillers.

The article focuses on the special section of the "adose Zone Journal" dedicated to Martinus "Rien" van Genuchten, highlighting his groundbreaking contributions to soil science. Topics include advancements in HYDRUS software for simulating subsurface flow, new mechanistic models for root water uptake, and research on preferential flow and its impact on groundwater contamination.

The article provides highlights about the evaluation of evapotranspiration products for hydrologic applications, long-term trends in streamflow and ecosystem provided by Kiamichi river watershed in Oklahoma from the Journal of American Water Resources Association's (JAWRA) technical papers.

The article offers information on several technical papers in the February 2013 issue of the "Journal of the American Water Resources Association," including one by Sanford and Selnick regarding an estimate of evapotranspiration in the U.S., one by Wigington and colleagues regarding a hydrologic landscape classification approach, and one by Arbuckle on the effectiveness of the Local Water Protection in Iowa.

This paper presents the recent WWRP/WMO Forecast Demonstration Project INCA-CE (INtegrating now- CAsting for Central Europe) co-funded by the European Union. Twenty-four partners of national and regional hydro-meteorological services, national and regional crisis and disaster management centers, and authorities for road management world-wide have participated in INCA-CE for international cooperation on nowcasting development, interdisciplinary cooperation for nowcasting applications and transnational cooperation for nowcasting services. INCA-CE has implemented the nowcasting system INCA at the project partner countries, applied INCA nowcasting in civil protection, operational hydrology and road safety, and improved the INCA system based on the end user's requirements. The main difference to other similar projects is that end user's involvement and the improvements involve the whole end user value chain. The project has developed several ideas for end users on how to interpret nowcasting products (INCA-SWING) and on how to deal with the nowcasting products in their working practice (INCA-MCPEX and ISW). INCA-CE is also oriented strongly to transnational cooperation in nowcasting development and implementation, in easy access to a homogenized set of nowcasting products from those INCA providers to end users in the region, and in the transnational use of real-time products by end users in cases of high impact weather across borders. [ABSTRACT FROM AUTHOR]

Groundwater, as an important store of freshwater, plays a more critical role in sustaining the ecosystem and enhancing human adaptation to changing climate than surface water. In particular, it can store large volumes of water to naturally buffer the pressure of water shortage against seasonal changes in rainfall. However, groundwater itself is also vulnerable to climate change, showing a great change in hydrologic cycle. Therefore, effective groundwater management has a strategic importance for China's water security. At present, China is facing a groundwater crisis because of the dual effects of natural and anthropogenic factors. Many new ideas and solutions have been given in previous studies on groundwater utilization and management. This paper vividly captures these studies. The paper summarizes groundwater properties and the situation of groundwater development and utilization. The paper also reports challenges, strategies and policies in groundwater sustainability. [ABSTRACT FROM AUTHOR]

The article discusses the potential health effects of drinking water with low Total Dissolved Solids (TDS) levels. The World Health Organization (WHO) highlights cases in the Czech and Slovak populations where the use of Reverse Osmosis (RO) systems in home taps led to complaints of cardiovascular disorders and other symptoms, indicating a deficiency in magnesium and possibly calcium. The WHO recommends that TDS levels in drinking water should be between 600 and 1,000 mg/l, but there is limited data on the adverse health effects of excess or low TDS. Different countries have set their own TDS standards, and RO manufacturers have introduced TDS controllers and mineral infusion cartridges to address concerns related to TDS levels. The article also provides the acceptable and permissible characteristics of drinking water according to the Bureau of Indian Standards. [Extracted from the article]

Many developing countries are experiencing rapid expansion in mining with associated water impacts. In most cases mining expansion is outpacing the building of national capacity to ensure that sustainable water management practices are implemented. Since 2011, Australia's International Mining for Development Centre (IM4DC) has funded capacity building in such countries including a program of water projects. Five projects in particular (principally covering experiences from Peru, Colombia, Ghana, Zambia, Indonesia, Philippines and Mongolia) have provided insight into water capacity building priorities and opportunities. This paper reviews the challenges faced by water stakeholders, and proposes the associated capacity needs. The paper uses the evidence derived from the IM4DC projects to develop a set of specific capacity-building recommendations. Recommendations include: the incorporation of mine water management in engineering and environmental undergraduate courses; secondments of staff to suitable partner organisations; training to allow site staff to effectively monitor water including community impacts; leadership training to support a water stewardship culture; training of officials to support implementation of catchment management approaches; and the empowerment of communities to recognise and negotiate solutions to mine-related risks. New initiatives to fund the transfer of multi-disciplinary knowledge from nations with well-developed water management practices are called for. [ABSTRACT FROM AUTHOR]

This paper outlines the application and usefulness of a software platform that enables hydrologists to develop custom functionality in a new hydrological modelling tool, eWater Source, designed for water resources planning and management. The flexible architecture of the software allows incorporation of third-party components as plug-ins to add new capabilities that are not built in. Plug-ins can be developed to adapt the software to suit the needs of hydrologists with modest software development knowledge. This can result in an improvement in workflow and efficiencies. In addition, modellers can use plug-ins to integrate hydrological process and management models that may not be able to be built in the normal tool. The paper introduces the plug-ins functionality of the modelling tool, its design and applications with three example plug-ins to demonstrate. These are: (1) a data processing plug-in to upscale urban environment models; (2) a management rule plug-in to calculate loss allowances for the Pioneer Valley; and (3) a model plug-in to integrate into a river system model. For planning purposes, the use of plug-ins is thought to be critical for modelling management rules for various jurisdictions since these can vary significantly between jurisdictions and change over time. [ABSTRACT FROM AUTHOR]

This paper addresses the difficult question of how to perform meaningful comparisons between neural network-based hydrological models and alternative modelling approaches. Standard, goodness-of-fit metric approaches are limited since they only assess numerical performance and not physical legitimacy of the means by which output is achieved. Consequently, the potential for general application or catchment transfer of such models is seldom understood. This paper presents a partial derivative, relative sensitivity analysis method as a consistent means by which the physical legitimacy of models can be evaluated. It is used to compare the behaviour and physical rationality of a generalised linear model and two neural network models for predicting median flood magnitude in rural catchments. The different models perform similarly in terms of goodness-of-fit statistics, but behave quite distinctly when the relative sensitivities of their inputs are evaluated. The neural solutions are seen to offer an encouraging degree of physical legitimacy in their behaviour, over that of a generalised linear modelling counterpart, particularly when overfitting is constrained. This indicates that neural models offer preferable solutions for transfer into ungauged catchments. Thus, the importance of understanding both model performance and physical legitimacy when comparing neural models with alternative modelling approaches is demonstrated. [ABSTRACT FROM AUTHOR]

The present paper focuses on demonstrating the capabilities of modern hydroinformatics tools in the field of environmental systems by integrating biotic and abiotic process modelling. Abiotic processes like hydrodynamic flow and transport phenomena are often formulated based on physical principles like conservation of mass, momentum and energy. These processes are adequately represented mathematically by second order partial differential equations that can be solved numerically in a variety of ways. However, in aquatic ecosystem modelling, biological/ecological processes play an important role and these processes are not always understood at the required level of detail to be captured in terms of conservation principles. In this paper two modelling approaches for biotic processes are explored for representing spatial pattern dynamics of aquatic ecosystems: (i) cellular automata (CA) and (ii) multi-agent systems (MAS) models, in combination with Delft 3D-WAQ for advanced flow and transport modelling. It is shown that CA are quite capable of capturing discrete growth phenomena like outcompeting plant species which are known to depend mainly on local effects. A MAS approach can combine nonlinearity, randomness and complexity of aquatic ecosystems, which can then be used to enhance the capabilities of available physics-based software systems like the DELFT3D software suite. [ABSTRACT FROM AUTHOR]

Hydroinformatics found its origin in the advancement of computational hydraulics in the early 1990s but has expanded considerably, both in scope and in application areas. It is now not only being applied in the fields of hydraulics and hydrology (often indicated by the colour blue), but also in environmental science and technology (green) as well as in knowledge systems and knowledge management (yellow). This paper focuses on urban (red) applications of hydroinformatics, taking urban flood and disaster management as an example. It is part of a sequence of papers, each focusing on a particular field (colour) of hydroinformatics, which together constitute a multi-coloured rainbow of application areas that hydroinformatics has expanded into over the past two decades or so. The combined papers on "Hydroinformatics in multi-colours" were presented as the opening keynote of the Workshop on Advances in Hydroinformatics held in Niagara Falls, in June 2007. In this paper-part red of the sequence-the role of urban hydroinformatics in assessing effects of climate change on urban flooding and health risk is addressed in relation to the UN Millennium Development Goals and illustrated on a case study of Dhaka, Bangladesh. [ABSTRACT FROM AUTHOR]

Formal uncertainty and sensitivity analysis techniques enable hydrologic modelers to quantify the range of likely outcomes, likelihood of each outcome and an assessment of key contributors to output uncertainty. Such information is an improvement over standard deterministic point estimates for making engineering decisions under uncertainty. This paper provides an overview of various uncertainty analysis techniques that permit mapping model input uncertainty into uncertainty in model predictions. These include Monte Carlo simulation, first-order second-moment analysis, point estimate method, logic tree analysis and first-order reliability method. Also presented is an overview of sensitivity analysis techniques that permit identification of those parameters that control the uncertainty in model predictions. These include stepwise regression, mutual information (entropy) analysis and classification tree analysis. Two case studies are presented to demonstrate the practical applicability of these techniques. The paper also discusses a systematic framework for carrying out uncertainty and sensitivity analyses. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANNs) are very effective statistical models for (1) extracting significant features or characteristics from complex data structures and/or for (2) learning nonlinear relationships involved in any input-output mapping. Another interesting aspect of ANN modeling is the fact that overall performance of these models is not greatly hampered by the presence of error-corrupted values in some input nodes. ANNs have gained interest in remote sensing applications as valuable inverse models that can retrieve physical characteristics of interest, such as precipitation, from remote sensing measurements collected from radars or satellites. The spatial coverage and high resolution of remote sensing measurements relative to ground-based measurements can improve the hydrological modeling of the water cycle at both local and global scales. This review paper intends to present recent advances in artificial neural network modeling of remote sensing applications in hydrology. This paper focuses on precipitation and snow water equivalent (SWE) retrievals from remote sensing data. [ABSTRACT FROM AUTHOR]

"Water conservation" means different things to different people and the principles of depletion and diversion are often confounded and misconstrued, particularly when the different perceptions of the value of water and units of analysis are involved. Many public policies and public and private investments have been implemented in the name of conserving water, particularly in irrigated agriculture. Unfortunately, many of these policies and investments cannot make additional water available to new users owing to the nature of closed basin hydrology. The assumption that farmers are low-efficiency irrigators is used to justify transfer of income and wealth to agricultural water users and others through direct investments and cost sharing programs. Instead, these programs serve to sustain and increase consumptive use of water in agriculture and disrupt the existing hydrologic balance. In arid climates, where deficit irrigation is practiced, conventional water conservation measures such as drip irrigation often result in increased depletion at the individual farm level and less water available for other users. This paper discusses water conservation misconceptions, particularly those related to irrigated agriculture in the arid southwestern United States. Deficit irrigation is a common practice throughout the southwest, the region is experiencing rapid population growth and naturally limited water supplies have been exacerbated by current drought conditions. In this paper, the water conservation impacts of drip irrigation, irrigation scheduling and canal lining are discussed in the context of the hydrological assumptions that are used to promote these technologies. The potential of drip irrigation, irrigation scheduling and canal lining to sustain and increase crop evapotranspiration in deficit irrigation environments is illustrated. Given hydrologic conditions, the authors conclude that accurate basin-wide accounting of water use, including equitable distribution based on existing legal entitlements would significantly contribute to water conservation efforts. [ABSTRACT FROM AUTHOR]

Achieving basic water security, both harnessing the productive potential of water and limiting its destructive impact, has always been a societal priority. To capture this duality, water security is defined here as the availability of an acceptable quantity and quality of water for health, livelihoods, ecosystems and production, coupled with an acceptable level of water-related risks to people, environments and economies. This paper looks broadly at those countries that have achieved water security, the paths they chose and the costs they paid, and those countries that have not achieved water security and how this constrains economies and societies. It defines three typologies: countries that have harnessed hydrology, those hampered by hydrology and those that are hostage to hydrology. It finds that countries remaining hostage to hydrology are typically among the world's poorest. They face "difficult" hydrologies often characterized by high inter- and intra-annual rainfall and runoff variability, where the level of institutional and infrastructure investment needed is very high and the ability to invest is low. This paper seeks to capture the dynamics of achieving water security in a hypothetical water and growth "S-curve", which illustrates how a minimum platform of investments in water institutions and infrastructure can produce a tipping point beyond which water makes an increasingly positive contribution to growth and how that tipping point will vary in different circumstances. As there are inevitable trade-offs, achieving water security is never without social and environmental costs; in some countries these are significant, often unforeseen and even unacceptable. This brief analysis suggests that the only historically demonstrated path to achieving water security at the national level has been through investment in an evolving balance of complementary institutions and infrastructure, but that lessons exist for following this basic path in more sustainable and balanced ways. Insights are provided for balancing and sequencing investments, adapting to changing values and priorities, and pushing down the social and environmental costs. The paper concludes that most water-insecure countries today face far greater challenges than those that achieved water security in the last century and are wealthy countries today. They face more difficult hydrologies and a greater understanding of and therefore greater responsibility for, the social and environment trade-offs inherent in water management. As the costs of poor countries not achieving water security, in terms of human suffering, sustained poverty, constrained growth and social unrest, would be very high, achieving water security is a challenge that must be recognized and must be met. [ABSTRACT FROM AUTHOR]

This paper describes an application of SVM over the Bird Creek catchment and addresses some important issues in developing and applying SVM in flood forecasting. It has been found that, like artificial neural network models, SVM also suffers from over-fitting and under-fitting problems and the over-fitting is more damaging than under-fitting. This paper illustrates that an optimum selection among a large number of various input combinations and parameters is a real challenge for any modellers in using SVMs. A comparison with some benchmarking models has been made, i.e. Transfer Function, Trend and Naive models, It demonstrates that SVM is able to surpass all of them in the test data series, at the expense of a huge amount of time and effort. Unlike previous published results, this paper shows that linear and nonlinear kernel functions (i.e. RBF) can yield superior performances against each other under different circumstances in the same catchment. The study also shows an interesting result in the SVM response to different rainfall inputs, where lighter rainfalls would generate very different responses to heavier ones, which is a very useful way to reveal the behaviour of a SVM model. [ABSTRACT FROM AUTHOR]

The paper questions the argument of the hydro-hegemony framework that counter-hegemonic mechanisms used by non-hegemons in transboundary rivers lead to a more equitable order of water and benefit-sharing, using the case of the Grand Ethiopian Renaissance Dam (GERD). It agrees with hydro-hegemony scholars that the GERD is a 'game changer' that challenges Egypt's hegemonic position, and an important step in the transition towards a new order in the Nile Basin. However, it scrutinises how Ethiopia and Egypt manage this transition through their policies to implement or contest the dam, and the conditions under which the GERD could lead to a more equitable order in the basin, and create incentives for cooperation beyond the project. It argues that Ethiopia's planning and implementation of the project, and Egypt's inconsistent response to it, have increased uncertainties about the benefits of the project to downstream countries, and even to Ethiopia, and fuelled the historical mistrust between the two countries. It suggests steps to build trust and translate the recent Declaration of Principles between the three Eastern Nile riparians into a benefit-sharing deal. [ABSTRACT FROM AUTHOR]

In the present paper we propose a new model of monthly river flow rate as a simple nonlinear function of air temperature and rainfall. Response surface methodology is used to analyze the observed monthly flow rates from 1950 to 1990 for Great Morava River, as the largest domestic river in Serbia. Obtained results indicate significant linear and quadratic effect of both individual factors, while two-factor interactions show significantly smaller influence, indicating occurrence of maximum flow rate for low temperature and high rainfall regime. Statistical reliability of the proposed model is verified by internal and external validation, the latter of which included comparison of predicted and observed values from 1991 to 2012. It is shown that predicted flow rates exhibit a similar statistical pattern as observed ones, with a satisfying value of Nash-Sutcliffe coefficient (NSE = 0.73), although the derived model cannot capture well the highest flow rates. Obtained results further indicate the sequence of residuals represents random time series, which is confirmed by appropriate test statistics and surrogate data testing. The advantage of using the derived model for hydrological simulations in river basins instead of existing ones lies in its explicit mathematical form, making it suitable for quick and reliable estimation and prediction of monthly flow rates. [ABSTRACT FROM AUTHOR]

Water research projects are often interdisciplinary and participatory in nature. Scientists and managers involved strive to create learning that advances science in various fields while providing benefits for society. They also face challenges of monitoring and evaluation (M&E) for accountability and measurement of impacts, required by funding agencies. In this paper we tested selected M&E processes and methods for their potential to increase capacity in a cross-cultural inter-disciplinary research setting of an urban water research project. A total of eight different qualitative and quantitative evaluation methods were assessed using two processes: self-evaluation by researchers, testing five methods; and the external evaluations by stakeholders, testing three methods. Both processes were found useful. Of the five self-evaluation methods tested, the Logical Frameworks method was deemed a good planning tool but not one contributing to learning. The qualitative (Factors of Success and Obstacles/Enablers) and the Best Case/Worst Case Scenarios quantitative method were effective learning methods. Tracking Change was found suitable for measuring learning. We recommended that a combination of methods be used in order to capture the full dynamic of projects in various stages. Explicit timelines for indicators and measures of project success are recommended for managing expectations of both researchers and funding agencies. [ABSTRACT FROM AUTHOR]

Applying feed-forward neural networks has been limited due to the use of conventional gradientbased slow learning algorithms in training and iterative determination of network parameters. This paper demonstrates a method that partly overcomes these problems by using an extreme learning machine (ELM) which predicts the hydrological time-series very quickly. ELMs, also called singlehidden layer feed-forward neural networks (SLFNs), are able to well generalize the performance for extremely complex problems. ELM randomly chooses a single hidden layer and analytically determines the weights to predict the output. The ELM method was applied to predict hydrological flow series for the Tryggevælde Catchment, Denmark and for the Mississippi River at Vicksburg, USA. The results confirmed that ELM's performance was similar or better in terms of root mean square error (RMSE) and normalized root mean square error (NRMSE) compared to ANN and other previously published techniques, namely evolutionary computation based support vector machine (EC-SVM), standard chaotic approach and inverse approach. [ABSTRACT FROM AUTHOR]

Owing to the increase in urban populations, there has also been an increased incidence of critical events, especially those related to floods and landslides. Since the implementation of the National Civil Defense System in Brazil, a focus on disaster management is no longer the answer when assisting those affected; instead, the answer has become managing disaster risk, in addition to the response, including prevention and minimizing the effects of the critical event. This paper highlights the actions for modernization and expansion of the hydro-logical monitoring network, in particular the alert network, the completion of an atlas of vulnerability to floods and the deployment of Situation Rooms in the states, with a view to strengthening the role of these bodies in disaster risk management, and enabling greater responsiveness to these events and the use of the information gathered as a water resources management tool, allowing for better use of public resources. [ABSTRACT FROM AUTHOR]

This article demonstrates how the availability of seawater desalination is important, not just as an additional source of water supply on a national scale, but as a potential 'game changer' in transboundary hydro-political interactions. The advent of desalination can change the nature of relations from a zero-sum game based on resource capture to a mutually beneficial business-like relationship typical in international commodity trade. It also allows for flexibility in policy approaches, and challenges the advantages and disadvantages hitherto thought of as inherent in upstream-downstream relations. This has wide ramifications for possible cooperation and conflict over international shared water resources. This study analyses the possible implications of desalination on hydro-politics, and then presents a case study of the hydro-political relations between Israel and Jordan in order to demonstrate how different aspects of transboundary political interactions are already being affected by the development of desalination. It demonstrates the ways in which the option of desalination allows states to pursue both unilateral and collaborative policies that were not practical in the period prior to desalination. The paper concludes by emphasizing the need for a revised analytical paradigm for analysis of hydro-politics in light of the development of desalination. [ABSTRACT FROM AUTHOR]

The relation of hydroinformatics to modern science is considered in relation to the origins and nature of modern science itself and to the technology that has assured the predominance of the European peoples over the peoples of most of the rest of the world for some 250 years. The current increasingly rapid reversal of this predominance is introduced with special reference to Asia in general and China in particular. This reversal is seen as a consequence of a transmutation in societies generally from modern conditions to postmodern conditions. The relation between knowledge providers and knowledge consumers is then introduced and related to the advent of the Internet and further to the World Wide Web, and further again to mobile devices. It is explained that the numerical predominance of China in access to the Web and to mobile telephony has proceeded alongside Chinese government initiatives that have supported this social development. The present contribution follows upon one with the same main title that was directed specifically to the Islamic world and another directed more generally to North-East Asia. Since this paper is directed almost exclusively towards China, it traces some developments currently occurring in China that exemplify its theses. [ABSTRACT FROM AUTHOR]

With the increasing complexity of hydrologic problems, data collection and data analysis are often carried out in distributed heterogeneous systems. Therefore it is critical for users to determine the origin of data and its trustworthiness. Provenance describes the information life cycle of data products. It has been recognised as one of the most promising methods to improve data transparency. However, due to the complexity of the information life cycle involved, it is a challenge to query the provenance information which may be generated by distributed systems, with different vocabularies and conventions, and may involve knowledge of multiple domains. In this paper, we present a semantic knowledge management framework that tracks and integrates provenance information across distributed heterogeneous systems. It is underpinned by the Integrated Knowledge model that describes the domain knowledge and the provenance information involved in the information life cycle of a particular data product. We evaluate the proposed framework in the context of two real-world water information systems. [ABSTRACT FROM AUTHOR]

Global climate change and local development make water supply one of the most vulnerable sectors in Australia. The Australian government has therefore commissioned a series of projects to evaluate water availability and the sustainable use of water resources in Australia. This paper discusses a river system modelling platform that has been used in some of these nationally significant projects. The platform consists of three components: provenance, modelling engine and reporting database. The core component is the modelling engine, an agent-based hydrological simulation system called the Integrated River System Modelling Framework (IRSMF). All configuration information and inputs to IRSMF are recorded in the provenance component so that modelling processes can be reproduced and results audited. The reporting database is used to store key statistics and raw output time series data for selected key parameters. This river system modelling platform has for the first time modelled a river system at the basin level in Australia. It provides practitioners with a unique understanding of the characteristics and emergent behaviours of river systems at the basin level. Although the platform is purpose-built for the Murray-Darling Basin, it would be easy to apply it to other basins by using different river models to model agent behaviours. [ABSTRACT FROM AUTHOR]

Simulation models of watershed hydrology (also referred to as "rainfall-runoff models") are calibrated to the best available streamflow data, which are typically published discharge time series at the outlet of the watershed. Even after calibration, the model generally cannot replicate the published discharges because of simplifications of the physical system embedded in the model structure and uncertainties of the input data and of the estimated model parameters, which, although optimized for the given calibration data, remain uncertain. The input data errors are caused by uncertainties in the forcing data, such as precipitation and other climatological data, and in the published discharges used for calibration. In the numerical algorithms used for calibration, the published discharges are often assumed to be without error, but they are themselves uncertain, typically having been computed using ratings, which are models fitted to uncertain discharge measurements. In this study, uncertainty of published daily discharge data and how the discharge uncertainty is transmitted to the parameter values of the Hydrological Simulation Program-FORTRAN (HSPF) rainfall-runoff model and to the simulated discharge at both calibration and prediction locations were investigated for the Lake Michigan diversion in northeastern Illinois and northwestern Indiana. The HSPF model used in this study is used by the U.S. Army Corps of Engineers as part of quantifying the diversion of water from Lake Michigan by the State of Illinois. In this study, the model is calibrated jointly at two watersheds in the study area; the resulting model is considered the base model in this study. Seven other gaged watersheds in the study area are used for testing predictive simulations. A Bayesian rating curve estimation (BaRatin) approach, the BaRatin stage-period-discharge (SPD) method, was used to estimate the uncertainty of the published discharge from the calibration watersheds. To characterize the effect of the discharge uncertainty on parameter values, the HSPF model parameters were recalibrated to 17 nonrandomly selected pairs of discharge series from the BaRatin SPD analysis. To provide an indicator of the effect of parameter uncertainty to compare to the effect of discharge uncertainty, 1,000 parameter sets also were randomly generated from the estimated parameter covariance matrix of the base model. The recalibrated and random parameter sets were then used in HSPF simulations of discharge at the two calibration watersheds and at the seven prediction watersheds. Selected discharge summary statistics--the period-of-study (POS, water years 1997 to 2015) mean discharge, selected flow-duration curve (FDC) quantiles, and water year mean discharges--are used to characterize the variability between simulated and published discharge. A normalized variability index (VN) is used as a measure of the uncertainty of flow statistics arising from the uncertainty of the sources considered in this study. When this index is at least 1, the variability of the simulations is large enough to explain the median error between simulated and published values, although offsetting errors from other sources are also likely. When the index is appreciably less than 1, the variability of the simulations is clearly insufficient to explain the median error between simulated and published values. At the two calibration watersheds and for results of the two simulation sets considered together, the VN values ranged from 0.2 to 0.8 for POS mean discharge, from 0.3 to 0.6 in the median for a set of FDC quantiles, and from 0.1 to 0.2 in the median for water year mean discharges. These values indicate that substantial uncertainty remains unexplained. Even though two watersheds were used in calibration, that calibration was highly constrained because it was applied to the watersheds simultaneously and was subject to parameter regularization that constrained the adjustment of the parameters from their initial values. These constraints were applied to avoid overfitting to the calibration watersheds and thus to increase the likelihood that the resulting parameters would give accurate results at watersheds not used in the calibration, but they created a parameter transfer error in the calibration watershed results shown by the balancing of errors between the two watersheds. Additional remaining error sources include model structural error and meteorological forcing error to the degree that the calibration was unable to adjust the parameters to account for these errors. At the prediction watersheds, the corresponding VN values were almost always substantially lower than those values at the calibration watersheds. This result is expected because the prediction watersheds have additional uncertainty, including parameter transfer error. The work described in this report provides preliminary estimates of a limited range of sources of error in predicted discharge uncertainty. Future work would be beneficial to obtain a better statistical characterization of the effect of the uncertainty of calibration discharge series and to address additional sources of uncertainty, such as from precipitation input data used in calibration and prediction and from structural (model) errors. [ABSTRACT FROM AUTHOR]

Stormwater reduction measures, or green infrastructure, were implemented in the parking area at Gary City Hall, Gary, Indiana, with the intention of reducing stormwater discharge to the sewers. A study area, including a centrally located rain garden and the surrounding paved surfaces and green space, was instrumented during both a preconstruction and a postconstruction period to (1) develop water budgets to improve understanding of the rain garden hydrology and (2) determine the quantity of stormwater runoff that was diverted and retained by the green infrastructure instead of reaching the combined storm and sanitary sewer. The study was focused on warm-season precipitation and was monitored during spring, summer, and fall of 2016, 2017 and 2018. Before construction of the rain garden in the parking lot of Gary City Hall in 2017, nearly all precipitation was conveyed away from the parking lot by underground drains, discharged to the sewer, and treated as sanitary waste at the Gary Sanitary District's treatment plant or discharged directly to local waterways if stormflow exceeded capabilities of the sewage treatment plant. A goal of the Great Lakes Restoration Initiative is the reduction of sewer overflows to local waterways to improve the quality of water entering the Great Lakes. Cities such as Gary benefit financially and environmentally by reducing discharges of stormwater runoff to the sewer system, eliminating the need for treatment. Before implementation of green infrastructure at Gary City Hall, approximately 25 percent of precipitation (approximately 10,200 cubic feet) discharged as stormwater to the sewers through the parking lot drain. After implementation, 2 percent of precipitation discharged to the sewers. For the spring, summer, and fall seasons of 2017 and 2018, 21-24 percent (about 10,700-19,700 cubic feet) of precipitation was captured by the newly installed rain garden. Stormwater discharged to the rain garden infiltrated the sandy soil and was later evaporated from the soil surface, was transpired by plants, or recharged the underlying groundwater aquifer. The percent reduction in stormwater discharged to the storm sewer after the construction of the rain garden was 80.3 percent, equating to approximately 21,400 and 39,300 gallons of stormwater in 2017 and 2018, respectively. [ABSTRACT FROM AUTHOR]

The U.S. Geological Survey, in cooperation with the city of Harrisonville, Missouri, assessed flooding of Muddy Creek resulting from varying precipitation magnitudes and durations, antecedent runoff conditions, and channel modifications (cleaned culverts and added detention storage). The precipitation scenarios were used to develop a library of flood-inundation maps that included a 3.8-mile reach of Muddy Creek and tributaries within and adjacent to the city. Hydrologic and hydraulic models of the upper Muddy Creek study basin were used to assess streamflow magnitudes associated with simulated precipitation amounts and the resulting flood-inundation conditions. The U.S. Army Corps of Engineers Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS; version 4.4.1) was used to simulate the amount of streamflow produced from a range of precipitation events. The Hydrologic Engineering Center-River Analysis System (HEC-RAS; version 5.0.7) was then used to route streamflows and map resulting areas of flood inundation. The hydrologic and hydraulic models were calibrated to the September 28, 2019; May 27, 2021; and June 25, 2021, runoff events representing a range of antecedent runoff conditions and hydrologic responses. The calibrated HEC-HMS model was used to simulate streamflows from design rainfall events of 30-minute to 24-hour durations and ranging from a 100-to 0.1-percent annual exceedance probability. Flood-inundation maps were produced for reference stages of 1.0 foot (ft), or near bankfull, to 4.0 ft, or a stage exceeding the 0.1-percent annual exceedance probability interval precipitation, using the HEC-RAS model. The results of each precipitation duration-frequency value were represented by a 0.5-ft increment inundation map based on the generated peak streamflow from that rainfall event and the corresponding stage at the Muddy Creek reference location. Seven scenarios were developed with the HEC-HMS hydrologic model with resulting streamflows routed in a HEC-RAS hydraulic model, and these scenarios varied by antecedent runoff condition and potential channel modifications. The same precipitation scenarios were used in each of the seven antecedent runoff and channel conditions, and the simulation results were assigned to a flood-inundation map condition based on the generated peak flow and corresponding stage at the Muddy Creek reference location. [ABSTRACT FROM AUTHOR]

Hydrologic and geophysical components interact to produce streambed scour. This study investigates methods for improving the utility of estimates of hydrologic flow in streams and rivers used when evaluating potential pier scour over the design-life of highway bridges in Virginia. Recent studies of streambed composition identify potential bridge design cost savings when attributes of cohesive soil and weathered rock unique to certain streambeds are considered within the bridge planning design. To achieve potential cost savings, however, attributes and effects of scour forces caused by water movement across the streambed surface must be accurately described and estimated. This study explores the potential for improving estimates of the hydrologic component, namely hydrologic flow, afforded by empirically based deterministic, probabilistic, and statistical modeling of flows using streamgage data from 10 selected sites in Virginia. Methods are described and tools are provided that may assist with estimating hydrological components of flow duration and potential cumulative stream power for bridge designs in specific settings, and calculation of comprehensive projections of anticipated individual bridge pier scour rates. Examples of hydrologic properties needed to determine the rates of streambed scour are described for sites spanning a range of basin sizes and locations in Virginia. Deterministic, probabilistic, and statistical modeling methods are demonstrated for estimating hydrological components of streambed scour over a bridge design lifespan. Eight tools provide examples of streamflow analysis using daily and instantaneous streamflow data collected at 10 study sites in Virginia. Tool 1 provides a generalized system dynamics model of streamflow and sediment motion that may be used to estimate hydrologic flow over time. Tool 2 illustrates at-a-station hydraulic geometry using methods pioneered by Leopold and others. Tool 3 provides a system dynamics model developed to test the use of Monte-Carlo sampling of instantaneous streamflow measurements to augment and increase precision of site-specific period-of-record daily-flow values useful for driving stream-power and streambed scour estimates. Tool 4 integrates deterministic modeling, maximum likelihood logistic regression, and Monte-Carlo sampling to identify probable hydrologic flows. Tool 5 provides instantaneous flow hydrologic envelope profiles, using measured instantaneous flow data integrated with measured daily-flow value data. Tool 6 provides precise estimates of hydrologic flow over entire data time-series suitable for driving scour simulation models. Tool 7 provides a threshold of flow and probability of time-underload interactive calculator that allows selection of a desired bridge design lifespan, ranging from 1 to 250 years, and identification of a flow interval of interest. Tool 8 provides a flow-random sampling interactive tool, developed to facilitate easy access to large datasets of randomly sampled flow data measurements from unique locations for purposes of computing and testing future models of bridge pier scour. [ABSTRACT FROM AUTHOR]

Hydrologic extremes, whether periods of drought or flooding, are occurring more frequently with greater severity and can have substantial economic impacts. Along with flooding, the timing and volume of streamflow also is changing across the United States. The focus of this report is to characterize a unique trend in mean annual streamflow occurring in eastern North and South Dakota, hereafter referred to as the eastern Dakotas, that is not being observed anywhere else in the conterminous United States. Streamflow records for 1,853 U.S. Geological Survey streamgages obtained from the U.S. Geological Survey National Water Information System database with a continuous record of mean annual streamflow during water years 1960-2019 were included in this study. Using a Kendall tau statistical test (p-value less than or equal to 0.10), 573 streamgages had a statistically significant upward trend in mean annual streamflow and are primarily located in the Midwest and northeastern United States. Of the streamgages, 182 had a statistically significant downward trend and are located primarily in the western and southeastern States. Several sites had increases in streamflow between 100 and 500 percent. Most of the streamgages with the highest increases in mean annual streamflow are along the same rivers in the eastern Dakotas, regardless of basin size. A comparison of mean annual streamflow of the last decade (2010-19) to the first decade (1960-69) of the study period shows that the largest increases in annual streamflow volumes in the United States also are in the eastern Dakotas. Among all 1,853 streamgages in the United States, the Sheyenne River near Warwick, North Dakota (U.S. Geological Survey station 05056000), has the greatest percent change, with an increase of 486 percent. Several factors may be contributing to increasing trends in streamflow in the eastern Dakotas and may include, in part, precipitation changes owing to climatic variation within the region, geologic makeup of the subsurface, and land-use changes. A better understanding of these research areas will help producers, resource managers, and infrastructure engineers to make more informed environmental and economic decisions. [ABSTRACT FROM AUTHOR]

Frequent and prolonged military training maneuvers are an intensive type of land use that may disturb land cover, compact soils, and have lasting effects on adjacent stream hydrology and ecosystems. To better understand the potential effect of military training on hydrologic and environmental processes, the U.S. Geological Survey in cooperation with the U.S. Army established hydrologic and water-quality datacollection networks at the U.S. Army Garrison Fort Carson (AGFC) in 1978 and at the Piñon Canyon Maneuver Site (PCMS) in 1982. The purpose of this report is to present precipitation, streamflow, suspended-sediment, and water-quality data collected by the U.S. Geological Survey at the AGFC and PCMS for water years (WYs) 2016-18 and to evaluate those data in relation to long-term data from the AGFC and PCMS. In WYs 2016-18, the U.S. Geological Survey monitored 26 sites on the AGFC and 17 sites on the PCMS for precipitation amount, streamflow, suspended sediment, and (or) water quality. [ABSTRACT FROM AUTHOR]

The article focuses on the hydrologic and geochemical characterization of the Petaluma River watershed in Sonoma County, California. The study examines the availability of groundwater as a supplemental water source and the development of a groundwater sustainability plan. Major findings include the limited extent of water-bearing units in the watershed; the influence of surface-water hydrology on groundwater quality and supply; and the identification of groundwater recharge sources.

The article focuses on the development of the Yucaipa Valley Integrated Hydrologic Model (YIHM) using the Groundwater and Surface-water FLOW model (GSFLOW) to simulate the hydrologic system in the Yucaipa Valley watershed California, U.S. Topics covered include model discretization; land-surface characteristics; soils; topography and stream network; and also discusses about the climate inputs for the model.

The integrated water resources management (IWRM) paradigm has emerged as the main guiding framework for water resources development and management. Since the IWRM approach started to gain prominence with the 1992 Rio de Janeiro Summit and the Dublin Conference, developing and developed countries worldwide have adopted and transposed the tools and principles embodied in this holistic approach into their national policies as well as their regulatory and institutional frameworks. The scientific community has performed extensive studies within the IWRM field. In fact, there is a growing literature analysing multi-dimensional functions to pursue an IWRM approach in water resources management. The main objective of this study is to perform a literature review of the scientific knowledge in the IWRM field published between the years 2000 and 2011. A total of 353 papers published in scientific journals were carefully reviewed and extracted from the ISI Web of Science database. The main results show that: (a) the dominant research topics in IWRManalysis focus on its institutional framework, on equitable water allocation (sustainable management of water resources), and on IWRM implementation and stakeholder participation; and (b) the leading countries in scientific research into IWRM are Germany, the USA and South Africa. [ABSTRACT FROM AUTHOR]

This paper presents the first basin-wide assessment of the potential impact of climate change on the hydrology and production of the Ganges system, undertaken as part of the World Bank's Ganges Strategic Basin Assessment. A series of modeling efforts -- downscaling of climate projections, water balance calculations, hydrological simulation and economic optimization -- inform the assessment. We find that projections of precipitation across the basin, obtained from 16 Intergovernmental Panel on Climate Change-recognized General Circulation Models are highly variable, and lead to considerable differences in predictions of mean flows in the main stem of the Ganges and its tributaries. Despite uncertainties in predicted future flows, they are not, however, outside the range of natural variability in this basin, except perhaps at the tributary or sub-catchment levels. We also find that the hydropower potential associated with a set of 23 large dams in Nepal remains high across climate models, largely because annual flow in the tributary rivers greatly exceeds the storage capacities of these projects even in dry scenarios. The additional storage and smoothing of flows provided by these infrastructures translates into enhanced water availability in the dry season, but the relative value of this water for the purposes of irrigation in the Gangetic plain, and for low flow augmentation to Bangladesh under climate change, is unclear. [ABSTRACT FROM AUTHOR]

This paper presents the geologic and hydrogeologic features of the Ojo de Agua zone in the southern basin of Guatemala City where a battery of water wells produces around 72% of the groundwater extracted from the aquifers of the central valley. The exploited outflow at Ojo de Agua represents 20% of the total production of Guatemala City. Therefore, Ojo de Agua is of essential importance for the water supply of the city making it is necessary to be exploit in a sustainable manner. This research is necessary to determine a conceptual hydrologic model and to establish new sites for water wells. The geology is conformed by lava flows, pyroclasts and sediments of variable permeability. An upper aquifer and lower aquifer have been established. The upper aquifer is conformed by pyroclasts and lake and fluvial sediments, with primary permeability and unconfined type. The aquifer has transmisivity values of 50 to 750 m²/day for the pyroclastic materials, and 150 to 2000 m²/day for the sediment materials. The storage coefficient is 0,09 and 0.20 respectively. The lower aquifer is confined and has secondary permeability; transmisivity varies from 1600 to 9500 m²day and the volcanic rocks have a storage coefficient of 0,014. The static levels of the water wells of Ojo de Agua have been fell down an average of 9 m in a period of over 20 years; the maximum drop registered is 13,2 m. The actual groundwater level depth is 12 to 14 m below ground level. Surging springs were reported in the area before the groundwater exploitation. The outflow of the main water wells varies from 134 to 232 1/s, for a total of 1675 1/s. The direction of groundwater flow is mainly north-south, controlled by a fault system with the same orientation that has developed horst and graben structures nearby. [ABSTRACT FROM AUTHOR]

The increasing demand for uncertainty assessment in stream-flow forecasts has drawn the hydrological community's interest toward ensemble forecasting techniques. The widespread deterministic hydrological forecasting point of view focuses to a great extent on the search for a hydrological model that would come as close as possible to "perfection" (i.e. the aim is to implement a model that produces a point forecast that is as close as possible as the observed outcome). On the other hand, ensemble forecasting departs from the deterministic point of view by avoiding the assumption that the "perfect" model exists and instead focuses on issuing a type of forecast that accounts explicitly for the uncertainty inherent to the forecasting process as a whole. In this paper, one-day-ahead hydrological ensemble forecasts obtained by stacked neural networks are presented and analysed. To do so, three simple performance assessment criteria are presented. Those criteria were originally developed in the meteorological and statistical communities to accommodate the need for a quality assessment methodology that is coherent with the probabilistic nature of ensemble weather forecasts. It will be shown that, even though the ensemble forecasts suffer from underdispersion, they outperform point forecasts. [ABSTRACT FROM AUTHOR]

After a brief review of the mutation from modern to postmodern conditions of society, that is, from societies of knowers to societies of consumers of knowledge, the position of the knowledge provider in hydroinformatics is introduced. The provider's changing role in a society with an ever-increasing emphasis on communication is introduced. The sociotechnical forces that have driven numerical modelling, first from second to third generation, then to the fourth generation, and now into a fifth generation, are explicated. These forces are exemplified by an increasingly active stakeholder participation in projects, joint policy formulation and on-line management. The applications to the increasingly problematic developments in the so-called 'Third World' are then considered. The overall consequences for the future of numerical modelling practice are then explored. The role of open-source software developments interacting with proprietorial software, together with the development and introduction of service-oriented architectures are explained. The concept of the knowledge supply chain is then advanced to introduce the concept of the extended halo of the global knowledge provider. This paper concludes with an analysis of appropriate and less appropriate business models. [ABSTRACT FROM AUTHOR]

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In this paper we present an object-oriented concept for numerical simulation of multi-field problems for coupled hydrosystem analysis. Individual (flow) processes modelled by a particular partial differential equation, i.e. overland flow by the shallow water equation, variably saturated flow by the Richards equation and saturated flow by the groundwater flow equation, are identified with their corresponding hydrologic compartments such as land surface, vadose zone and aquifers, respectively. The object-oriented framework of the compartment approach allows an uncomplicated coupling of these existing flow models. After a brief outline of the underlying mathematical models we focus on the numerical modelling and coupling of overland flow, variably saturated and groundwater flows via exchange flux terms. As each process object is associated with its own spatial discretisation mesh, temporal time-stepping scheme and appropriate numerical solution procedure. Flow processes in hydrosystems are coupled via their compartment (or process domain) boundaries without giving up the computational necessities and optimisations for the numerical solution of each individual process. However, the coupling requires a bridging of different temporal and spatial scales, which is solved here by the integration of fluxes (spatially and temporally). In closing we present three application examples: a benchmark test for overland flow on an infiltrating surface and two case studies - at the Borden site in Canada and the Beerze-Reusel drainage basin in the Netherlands. [ABSTRACT FROM AUTHOR]

Catchment water quality models have many parameters, several output variables and a complex structure leading to multiple minima in the objective function. General uncertainty/optimization methods based on random sampling (e.g. GLUE) or local methods (e.g. PEST) are often not applicable for theoretical or practical reasons. This paper presents ‘ParaSol’, a method that performs optimization and uncertainty analysis for complex models such as distributed water quality models. Optimization is done by adapting the Shuffled Complex Evolution algorithm (SCE-UA) to account for multi-objective problems and for large numbers of parameters. The simulations performed by the SCE-UA are used further for uncertainty analysis and thereby focus the uncertainty analysis on solutions near the optimum/optima. Two methods have been developed that select ‘good’ results out of these simulations based on an objective threshold. The first method is based on x2 statistics to delineate the confidence regions around the optimum/optima and the second method uses Bayesian statistics to define high probability regions. The ParaSol method was applied to a simple bucket model and to a Soil and Water Assessment Tool (SWAT) model of Honey Creek, OH, USA. The bucket model case showed the success of the method in finding the minimum and the applicability of the statistics under importance sampling. Both cases showed that the confidence regions are very small when the x2 statistics are used and even smaller when using the Bayesian statistics. By comparing the ParaSol uncertainty results to those derived from 500,000 Monte Carlo simulations it was shown that the SCE-UA sampling used for ParaSol was more effective and efficient, as none of the Monte Carlo samples were close to the minimum or even within the confidence region defined by ParaSol. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the exact form of Fisher information matrix for a four-parameter kappa distribution (K4D) is determined. The K4D is so general that includes a variety of distributions as special cases. The necessary condition for the existence of Fisher information matrix is for , . [Copyright &y& Elsevier]

This paper introduces an application of machine learning, on real data. It deals with Ensemble Modeling, a simple averaging method for obtaining more reliable approximations using symbolic regression. Considerations on the contribution of bias and variance to the total error, and ensemble methods to reduce errors due to variance, have been tackled together with a specific application of ensemble modeling to hydrological forecasts. This work provides empirical evidence that genetic programming can greatly benefit from this approach in forecasting and simulating physical phenomena. Further considerations have been taken into account, such as the influence of Genetic Programming parameter settings on the model's performance. [ABSTRACT FROM AUTHOR]

Gamma distributions are some of the most popular models for hydrological processes. In this paper, a very flexible family which contains the gamma distribution as a particular case is introduced. Evidence of flexibility is shown by examining the shape of its probability density function (pdf). A treatment of the mathematical properties is provided by deriving expressions for the n th moment. Estimation and simulation issues are also considered. Finally, a detailed application to drought data from the State of Nebraska is illustrated. [Copyright &y& Elsevier]

This paper implements the inverse approach for forecasting hydrological time series in an efficient way using a micro-GA (mGA) search engine. The inverse approach is based on chaos theory and it involves: (1) calibrating the delay time ((), embedding dimension (m) and number of nearest neighbors (k) simultaneously using a single definite criterion, namely optimum prediction accuracy, (2) verifying that the optimal parameters have wider applicability outside the scope of calibration, and (3) demonstrating that chaotic behaviour is present when optimal parameters are used in conjunction with existing system characterization tools. The first stage is conducted efficiently by coupling the Nonlinear Prediction (NLP) method with mGA using a lookup facility to eliminate costly duplicate NLP evaluations. The mGA-NLP algorithm is applied to a theoretical chaotic time series (Mackey–Glass) and a real hydrological time series (Mississippi river flow at Vicksburg) to examine its efficiency. Results show that: (1) mGA is capable of producing comparable or superior triplets using only up to 5% of the computational effort of all possible points in the search space, (2) the lookup facility is very cost-effective because only about 50% of the triplets generated by mGA are distinct, (3) mGA seems to produce more robust solutions in the sense that the record length required to achieve a stable optimum triplet is much shorter, and (4) the prediction accuracy is not sensitive to the parameter k. It is sufficient to use k = 10 in future studies. In this way, the 3D search space could be reduced to a much smaller 2D search space of m and τ. Keywords chaotic time series; inverse approach; micro genetic algorithm; nonlinear prediction [ABSTRACT FROM AUTHOR]

Abstract: When selecting or developing a model to use for research it is important that the model structure and complexity meet the objectives of the research while avoiding problems from overparameterisation. In this paper a procedure is outlined for the selection or development of a model to be used to assist in locating and designing tree belt plantations on hillslopes. Sensitivity analysis and field data interpretation are used to define the important hillslope properties and processes occurring at a field site in southern New South Wales. These are combined with the research objectives to identify the model requirements for further study on tree belt plantations. A brief review of potentially suitable models available reveals that no single model meets all of the requirements. It is concluded that field data should be used to develop a simple cascading bucket model for hillslope hydrology using a top-down approach. [Copyright &y& Elsevier]

This paper seeks to exploit a recent data set obtained off the coast of New Jersey, USA in the summer of 1996. The two major objectives are to gain insight into mechanisms controlling the vertical structure, particularly the temperature and density, and into the subtidal frequency dynamics. The setting was strongly affected by three conditions: stratification was high, the bottom slope was comparable to the isopycnal slope, and buoyancy forcing from an upshelf freshwater source was, on average, of the same strength as wind forcing. Bottom mixed layer (bml) and surface mixed layer (sml) thicknesses increased offshore, opposite the sense predicted by standard formulations for stratified conditions. Maps of sml and bml thickness were coherent with maps of bml density, not with maps of vertical stratification. It appears that horizontal buoyancy flux from the Hudson coastal current sustains the stratified interior even very near shore. Well resolved vertical profiles at a mooring in 19 m water depth showed that above 1 m height off the bottom the Richardson number was very large, rendering vertical stress and eddy coefficients very small. In contrast at a deeper site offshore beyond the reach of freshwater intrusion a thick bml was present and vertical stresses and eddy coefficients were at expected levels. Moored instruments there revealed temporal variations in bml thickness which correlated with the strength and direction of the interior alongshelf current, but with the opposite sense found on the California shelf: thicker during upwelling and thinner during downwelling. The difference is well explained by the action of interior density changes at the bml edge produced by displacement of interior isopycnals. This action is significant when the ratio of isopycnal slope to bottom slope is of order one, as here. The subtidal dynamics featured high levels of bottom friction, despite the thin bml thicknesses nearshore. The large values of drag coefficient found are consistent with the large effective roughness heights induced by the orbital wave motion in this shallow water regime on an open coast. Bottom stress was comparable to wind stress both in mean values and in variations. No bottom stress reduction was evident, despite the sloping bottom and stratified interior. Volume transport in the bml rarely balanced the surface Ekman transport based on the alongshelf wind and rarely was consistent with bottom Ekman transport based on bottom stress. This implies that the flow field was seldom in a state of alongshelf invariance ("two-dimensional flow"). Despite the very shallow water depths, thermal wind balance was satisfied for the vertical shear of the alongshelf current. [ABSTRACT FROM AUTHOR]