bluuebunny/crossref_metadata_2025 huggingface dataset:
Subpermafrost Groundwater Modelling in Ny-Ålesund, Svalbard
Authors: Booij M. , Leijnse A. , Haldorsen S. , Heim M. , Rueslåtten H.
Published: May 2018

Svalbard is a high arctic archipelago where the permafrost thickness is 150-450 m and almost continuous in ice-free areas. The model work was carried out in Ny-Ålesund, where the subpermafrost aquifers are recharged by water from the bottom of the Vestre Lovénbreen glacier. One main discharge spring is found at the entrance of an old coal mine. The computer code SUTRA has been used to simulate two-dimensional fluid movement and energy transport in the ground under steady state conditions. For the simulation, a cross section with unit thickness parallel to groundwater flow has been chosen. With the resulting output of SUTRA, contour maps of the pressure, hydraulic head, temperature and velocity have been made. Residence times for different situations have been determined to be15 years as a minimum. In general there is a good agreement between the physical reality and the simulation results.
Neural Networks in the Ice-Correction of Discharge Observations
Authors: Huttunen Markus , Vehviläinen Bertel , Ukkonen Esko
Published: May 2018

We have applied three models, a neural network, a conceptual model and a combination of these two a hybrid model, to model the backwater effect of ice in a river. The neural network is a black-box model. It is based mainly on observed data and it lacks the expert knowledge of the system. The conceptual model is based on a physical description of the system. The data is used in optimizing the free parameters of the description. In the hybrid model, the neural network is modified so that the physical description of the conceptual model can be coded into the structure of the network. In the beginning of fitting, the hybrid network already performs as well as the conceptual model. During fitting also the structure of the physical description is optimized, not only the parameters of the description. The three models are rather different in form but in the modeling results there are only slight differences. Mean error of the models in ice-correction is 13-15 m3/s at an observation station where the mean backwater effect of the ice is 100 m3/s. The aim of this work is to develop a model for real time estimation of corrected discharge, which is used in error correction of a discharge forecast model. For this purpose the error of the best model is acceptable.
A Model for Water Exchange Between the Baltic Sea and the Gulf of Riga
Authors: Otsmann Mikk , Astok Villu , Suursaar Ülo
Published: May 2018

A model for water exchange of a basin connected to the open sea by two channels has been worked out. The model is applied on the Gulf of Riga, where the water exchange processes versus strong landbased inflow of nutrients are the most important factors in formation of the trophic status of the Gulf.

The model's response both to stationary external conditions and nonstationary impulses (changes in the sea level, wind and riverine inflow) is analysed and possibilities for matter exchange calculations are discussed. It appeared that the water exchange depends strongly on the configuration and position of the straits. The water exchange in such a two-channel system is considerably different (and stronger) than in the case of a one-channel version. The main external force for the Gulf appeared to be the wind.
Wind-induced Precipitation Undercatch of the Hellmann Gauges
Authors: Yang Daqing , Elomaa Esko , Tuominen Asko , Aaltonen Ari , Goodison Barry , Gunther Thilo , Golubev Valentin , Sevruk Boris , Madsen Henning , Milkovic Janja
Published: May 2018

The Hellmann gauges have been widely used as the official precipitation measurement instruments in 30 countries. From 1986 to 1993, the accuracy and performance of the Hellmann gauges were evaluated during the WMO Solid Precipitation Measurement Intercomparison at 4 stations in Finland, Russia, Germany, and Croatia. The double fence intercomparison reference (DFIR) was the reference standard used at all the Intercomparison stations. The data for the Hellmann gauges were compiled from measurements made at the 4 WMO intercomparison sites. These data represent a variety of climates, terrains and exposures. The effects of meteorological factors, such as wind speed, type of precipitation and temperature, on gauge catch efficiency were investigated. For snow and mixed precipitation, wind speed was found to be the most important factor determining the gauge catch and air temperature had a secondary effect. The relations of gauge catch ratio versus wind speed and temperature on a daily time scale were derived and presented for snow and mixed precipitation. Independent tests of the relations have been conducted at the WMO intercomparison stations and reasonable agreement between the corrected precipitation and the DFIR observation has been obtained. These relations are therefore recommended to be used for test correction of gauge measured data. It is expected that implementation of these correction procedures to the current and archived records will significantly improve the accuracy and homogeneity of precipitation data.
Evaporation from Snow in the Central Sierra Nevada of California
Authors: Leydecker Al , Melack John M.
Published: May 2018

Evaporation from snow was calculated with the mean-profile method using single-level meteorological data at eight locations representing a variety of alpine and sub-alpine terrain in the central Sierra Nevada, California. Four to six years of data were analyzed at most of the sites. Evaporation from snow was highest in mid-winter, when the vapor pressure gradient between the snow surface and the air was at its maximum, and declined throughout the snowmelt season. Near the end of snowmelt, condensation of water vapor on the snow surface often matched or exceeded evaporative loss. Annual evaporation from the snowpack varied from 12 to 156 mm. We estimate mean annual regional evaporation in the sub-alpine and alpine zones (excluding evaporation from tree-captured snow and during wind re-deposition) as 80 to 100 mm, approximately 7 per cent of the maximum accumulation during an average snow year. Evaporation during snowmelt contributed only minor amounts to the total seasonal loss, typically around 25 mm, or about 2% of the maximum average accumulation.
Mathematical Model of Hydrological Processes METQ98 and its Applications
Authors: Ziverts A. , Jauja I.
Published: May 2018

The mathematical model METQ98 for runoff simulation is described. The METQ98 is developed from the model METUL (Krams and Ziverts 1993). Input data for the model are daily mean values of air temperature, precipitation and vapour pressure deficit. The spatial variability of surface processes is represented by dividing the river basin into hydrological response units (HRUs) depending on the land cover. The analysis of the model parameters is based on hydrological and meteorological data of the Vienziemite Brook basin. Also the influence of drainage on the model parameters is analysed. The results of application of the model to the Daugava River basin are presented.
An Overview of a Nested Watershed Study in Arctic Alaska
Authors: Kane D.L. , Hinzman L.D. , McNamara J.P. , Zhang Z. , Benson C.S.
Published: May 2018

The hydrology of a nest of three watersheds has been studied since 1992 on the North Slope of Alaska, with some additional data collected at individual sites previously. Hydrologic studies of nested watersheds are rare in the circumpolar arctic. Presented here is a comparison of the variability of important runoff-related processes from the headwater foothills to the low gradient, wetland dominated coastal area. Watersheds studied include Imnavait Creek, Upper Kuparuk River and finally the entire Kuparuk River. Also, runoff data from the low gradient Putuligayuk River, measured earlier (1970-1986), is included. Generally, rainfall constitutes 53 to 67 % of the annual precipitation. Most runoff is generated from the foothills; runoff is normally only generated from the coastal plain during snowmelt. Surface storage is an important process on the coastal plain where vertical processes (precipitation and evapotranspiration) are dominant during the summer. Continuous permafrost produces high soil moisture levels except where there are relatively steep slopes with gravity-induced drainage. Snowmelt results in a nearly saturated active layer with summer moisture levels closely allied with summer precipitation. High runoff ratios prevail during snowmelt and rainfall, except for the summer rainfall-generated runoff of the low gradient Putuligayuk River.
Ash on Snow a Tool – A Tool to Prevent Flooding?
Authors: Lundberg Angela , Beyerl H
Published: May 2018

Years with late spring in combination with thick snow-pack constitute risk for flooding. To decrease that risk, the possibility of spreading albedo-lowering material (wood ash) on parts of a basin snow has been examined. By blackening the snow more solar radiation is absorbed and the snowmelt is enhanced. If sun-exposed parts of the basin are ash-treated (before normal runoff starts) the runoff will be distributed over a longer period of time and the risk of flooding will be reduced. Wood ash in different concentrations was spread on small snow plots and melt rates and albedo were measured. For snow covered with 0.03 kg ash m−2, the albedo was decreased from ≈ 0.60 for natural snow to ≈ 0.25, resulting in ≈ 90% more absorbed short-wave radiation. Melt on the ash treated surface, (daily average snow water equivalent), was 70% larger than melt on natural snow (12 and 7 mm d−1 respectively). A five times larger concentration (0.15 kg m−2) only increased the melt rate to 14 mm d−1. The temperature-index method was shown to be inadequate for modelling the melt rate for the ash treated snow. A radiation-index model, based on absorbed incoming short wave radiation, was shown to model the melt rate better than the temperature-index method.
Fuzzy Clustering Neural Network as Flood Forecasting Model
Authors: Chang Fi-John , Chen Yen-Chang , Liang Jin-Ming
Published: May 2018

Flood forecasting is always a challenge in Taiwan, which has a subtropical climate and high mountains. This paper develops a fuzzy clustering neural network (FCNN), and implements this novel structure and reasoning process for flood forecasting. The FCNN has a hybrid learning scheme; the unsupervised learning scheme employs fuzzy min-max clustering to extract information from the input data. The supervised learning scheme uses linear regression to determine the weights of FCNN. The network, which learns from examples, is a hydrological processes theory-free estimator. Most of the parameters, weights of the network, are adjusted automatically during the network training. Only one parameter needs to be justified during constructing the flood forecasting models. The one-hour-ahead floods of the Lanyoung River during tropical storms are forecasted by the constructed models. Our results show that the simple but reliable model is capable of real time flood forecasting.
Transect Scale Solute Transport Measured by Time Domain Reflectometry
Authors: Persson Magnus , Berndtsson Ronny
Published: May 2018

Two quasi steady-state solute transport experiments were carried out in a loamy sand under field conditions. The flux was 40 mm/d in experiment 1 and 18.7 mm/d in experiment 2. Both water content (θ) and resident concentration (Cr) measurements were taken using 64 time domain reflectometry probes at depths ranging from 0.05 to 0.90 m. The Cr measurement was calibrated in situ for each probe location in the field. The convective dispersive equation (CDE) and convective lognormal transfer function (CLT) models were fitted to the breakthrough curves (BTCs). The results indicated fingered flow, which has been shown to exist in previous studies of this soil. The finger width was larger in experiment 1 leading to smaller horizontal heterogeneity and a relatively smaller solute transport velocity. The location of the fingers was consistent between the two experiments resulting in a high correlation between the velocity and mass balance fields. Mass balance calculations showed that the solute mass integrated over depth one day after the solute application was larger than the mass balance for the entire experiment (integrated over time). The probable reason being that solutes were transported out of the measurement volume by horizontal flow across the Ap/E horizon boundary. The investigation of the transport parameters revealed that both the CDE and CLT models could be successfully used to predict most individual BTCs. Horizontally averaged global CDE and CLT models were also fitted to the data. Global solute transport was better modeled with the CDE model in experiment 1, while in experiment 2, the CLT model was better. This study clearly shows the applicability of using TDR with the in situ calibration technique in field experiments with varying water content.
Relating Air Temperatures to the Depletion of Snow Covered Area in a Himalayan Basin
Authors: Singh Pratap , Bengtsson Lars , Berndtsson Ronny
Published: May 2018

A procedure for evaluating depletion of snow covered area (SCA) using mean air temperature has been outlined and tested. Because depletion of snow is a cumulative effect of climatic conditions in and around snow cover area, the cumulative mean temperature (CTM) at a nearby station should represent depletion of SCA. The study was carried out for Satluj basin (22,305 km2) located in the western Himalayan region. Melting starts around beginning of March, therefore, reference date for computing CTM was considered March 1. Data of three ablation seasons (1987-1989) were used to establish relationship between SCA and CTM. It was found that depletion of SCA is exponentially correlated with CTM (R2 > 0.98). An exponential reduction of SCA can be explained on the basis of snow distribution in the mountainous basins. This method has a potential for estimating missing data and extending time series on daily, weekly or monthly basis. Once the depletion trend is established in the basin in the first part of melt season, SCA can be simulated with good accuracy using CTM data for the rest period of melt season. Such applications can reduce the number of satellite images required for obtaining SCA information. A forecast of SCA can also be made using forecasted air temperatures. Impact of climate change on depletion of SCA over the melt period indicated that for the considered range of temperature increase (1-3°C), melting area of snow increased linearly with increase in temperature. An increase in temperature by 2°C enhanced the melting area of snow over the melt season by 5.1%.
Optical Properties of Dissolved Organic Matter in Finnish and Estonian Lakes
Authors: Sipelgas L. , Arst H. , Kallio K. , Erm A. , Oja P. , Soomere T.
Published: May 2018

The main objective of the present study is to test various methods for describing the absorption spectra of coloured dissolved organic matter (CDOM) and to determine the numerical values of some optical parameters of CDOM in lakes with diverse water quality. First, the parameters of an exponential model in different spectral intervals were determined. In addition, the suitability of some other models for the approximation of CDOM spectra was estimated. Specific absorption coefficients of CDOM were calculated from the absorption coefficients and dissolved organic carbon (DOC) concentrations. The experimental initial data were differences between spectral attenuation coefficients of filtered and distilled water. Two datasets were used: 1) for 13 Estonian and 7 Finnish lakes (altogether 404 spectra between 350 and 700 nm) measured by the Estonian Marine Institute (EMI); 2) for 10 Finnish lakes (73 spectra) measured by the Finnish Environment Institute (FEI).

The spectra of CDOM absorption coefficients (aCDOM) were calculated from experimental data taking into account the correction due to scattering properties of colloids in the filtered water. The total content of CDOM in natural waters of Estonian and Finnish lakes was expressed by means of aCDOM at the wavelength of 380 nm. It varied significantly, from 0.71 to 19.5 m−1, the mean value (of all the investigated lakes) being around 6.6 m−1. Slopes of the exponential approximation varied widely, from 0.006 to 0.03 nm−1. Averaged over all lakes values of slope for the interval 380-500 nm obtained from the EMI dataset are close to those obtained from the FEI dataset: from 0.014 nm−1 (without correction) to 0.016-0.017 nm-1 (with different types of correction). These results are in good correspondence with most published data.

Attempts to describe the spectra in the region of 350-700 nm by means of hyperexponential functions (∽ exp(-αλη)) show that: (1) η < 1 (in the case of traditional exponential approximation η = 1); (2) a promising idea is to seek the best fit only for wavelengths λ > λ1, where λ1 will be chosen taking into account the real shape of aCDOM spectra.

The mean value of the specific absorption coefficient (a*CDOM) at the wavelength 380 nm obtained in this study (0.44 L mg−1 m−1) is close to the values published in the literature, if we assume that a*CDOM (380) is calculated using the data of dissolved organic matter (DOM). The optically non-active fraction of DOM in our study was high and therefore a*CDOM (380) was considerably higher (1.01 L mg−1 m−1) than a*CDOM (380).

The results of the present work could be used in the modeling of underwater light field as well as in the interpretation of radiation measurements and optical remote sensing results.
Reliability of Model Predictions Outside Calibration Conditions
Authors: Seibert Jan
Published: May 2018

Predictions of probabilities and magnitudes of extreme events are essential for water management. One approach for flood estimation is the use of conceptual runoff models. This approach, however, can be questioned for the same reason as the approach of extreme-value statistics: the model has to be used for conditions far beyond those used for model development and calibration. In this study the HBV model, a conceptual runoff model, was applied to four different catchments and differential split-sample testing (calibration on years with lower runoff peaks and testing it on years with higher peaks) was used to evaluate model performance for the situation when the model has to be used to simulate runoff during conditions different from those observed during calibration. To assess the value of improved calibration different goodness-of-fit measures were used, which allowed to explicitly consider the ability of the model to simulate groundwater-levels and peak flows. The results indicated that applying a model to conditions different from those during the calibration period might not give accurate results and that improved calibration procedures might not automatically provide more accurate flood estimations.
Hydraulic Modelling of Suspended Sediment Deposition in an Inundated Floodplain of the Nemunas Delta
Authors: Vaikasas Saulius , Rimkus Alfonsas
Published: May 2018

Floods of meadows in the delta of the river Nemunas contribute to the deposition and retention of sediments and nutrient that would otherwise deposit in the Curonian Lagoon. In grassland area of the Nemunas delta the formation of alluvial soil occurs according to the flood dynamic rules: water discharging into the valley leaves suspended sediments on the soil surface. By mathematical modelling it was established that about 35% of suspended sediments inflow deposited there. Due to sand particles deposited during the study period (1950-1991), the natural river bank levee rose by 0.3 m. Fine clay and silt particles deposited uniformly within the entire model area and formed a 4-6 mm thick layer there. It contained about 50-60 t/ha of silt deposits. The valley soils were naturally fertilized with 250 t of potassium, 950 t of phosphorus, 38,000 t of calcium, and even 147,000 t of organic matter saturated with nitrogen. Certain amount of heavy metals also deposited there.

The deposition process has not yet been adequately investigated under the conditions of flow bed covered by grass. It was established that grass cover intensified the sediment deposition in the floodplain. Considering calculation results and measurement data, the process of suspended sediment deposition was analysed and new formulas were derived. It was established that in order to increase sedimentation in the valley, it would be necessary to increase water discharge overflowing from river bed into the delta valley.
Nutrient Losses and N & P Balances in Small Agricultural Watersheds in Estonia
Authors: lital Arvo , Loigu Enn , Vagstad Nils
Published: May 2018

The paper deals with nutrient runoff monitoring results and calculated nutrient budgets on catchment level in small agricultural watersheds in Estonia. A special programme for monitoring of nutrient losses was initiated and a network of monitoring stations, equipped with data-loggers and suitable devices for continuous flow measurement and flow-proportional automatic water sampling were established in Estonia in the mid-1990s. The research methodology is harmonized with the Nordic countries as well as with the other Baltic countries. The results indicate that nutrients losses are relatively low (generally below 11 kg N/ha and 0.9 kg P/ha). It can be partly explained by drastic changes in the Estonian agricultural practice in the 1990s but also by differences in runoff regime.

Nutrient balances were calculated for two catchments, based on the data collected from the farms, some special studies and water quality monitoring results in two watersheds in 1995 (1999) - 2001. The nutrient balances for the catchments turned positive after being negative both for nitrogen and phosphorus in the mid-1990s.
Mesoscale Circulations and Surface Energy Balance During Snowmelt in a Regional Climate Model
Authors: Mac Kay Murray D. , Szeto Kit , Verseghy Diana , Chan Ed , Bussières Normand
Published: May 2018

The Canadian Regional Climate Model has recently been coupled with an advanced, second generation land surface model - the Canadian Land Surface Scheme. In addition, high resolution land cover and soils data sets have been assembled on a 1 km horizontal resolution grid over North America. These data sets, along with the coupled model, provide a powerful tool for the examination of regional climate processes in complex, heterogeneous terrain. In a first application of the new modelling system, simulations of progressively higher horizontal resolution are performed over the Mackenzie Basin for the spring of 1995 in order to determine if turbulent fluxes associated with a heterogeneous land surface can generate mesoscale atmospheric circulations of relevance to the surface energy budget during the critical snow melt period.

We have found that shallow, diurnally forced mesoscale circulations associated with surface flux heterogeneity developed regularly throughout the snow melt period in the higher resolution experiments. In one case, a localized downdraft associated with a low level isothermal layer was found to enhance turbulent heat exchange with the underlying snow. The net importance of this process to the overall energy balance of the snowpack did increase with resolution, but remained relatively small for the resolutions considered here.
Modelling of seasonal effects of soil processes on N leaching in northern latitudes
Authors: Rankinen K. , Granlund K. , Bärlund I.
Published: May 2018

Concentrations of inorganic nitrogen (N) in non-polluted and undisturbed northern rivers are often lower during summer than during the dormant season. The great difference between summer and winter N concentrations probably reflects higher soil water N contents in the dormant season compared with the growing season, when inorganic N is usually retained effectively. Microbial activity in soil is observed even in sub-zero temperatures and it is generally assumed that in the northern latitudes some N mineralization occurs during winter. The dynamic, semi-distributed INCA (Integrated Nitrogen in Catchments) model was applied to the Simojoki river basin in the boreal zone in northern Finland. With this model process rates and loads of N can be simulated in different land use modes. The INCA model was not able to simulate the high inorganic N concentrations in the river water in winter unless N processes in sub-zero temperatures were included. The aim of this study was to compare the simulated N mineralization in two different land use modes: boreal forests on mineral soil and agricultural fields. Net N mineralization occurring during the season when soil is mainly frozen (November–April) accounted for 43% of the annual N mineralization. This work indicates the importance of over-winter N processes in northern areas, which should be taken into account when modelling nutrient leaching.
A modified Xinanjiang model and its application in northern China
Authors: Hu Caihong , Guo Shenglian , Xiong Lihua , Peng Dingzhi
Published: May 2018

The Xinanjiang model has been widely used in the humid regions in southern China as a basic tool for rainfall–runoff simulation, flood forecasting and water resources planning and management. However, its performance in the arid and semi-arid regions of northern China is usually not so good as in the humid regions. A modified Xinanjiang model, in which runoff generation in the watershed is based on both infiltration excess and saturation excess runoff mechanisms, is presented and discussed. Three different watersheds are selected for assessing and comparing the performance of the Xinanjiang model, the modified Xinanjiang model, the VIC model and the TOPMODEL in rainfall–runoff simulation. It is found that the modified Xinanjiang model performs better than the Xinanjiang model, and the models considering the Horton and Dunne runoff generation mechanisms are slightly better than those models considering the single runoff generation mechanism in semi-arid areas. It is suggested that the infiltration excess runoff mechanism should be included in rainfall–runoff models in arid and semi-arid regions.
Derivation of a root zone soil moisture algorithm and its application to validate model data
Authors: Lindau Ralf , Simmer Clemens
Published: May 2018

A retrieval algorithm for soil moisture within the uppermost metre of soil is presented. As calibration data, longtime soil moisture measurements from the former Soviet Union are used. The retrieval works in two steps. First, the distribution of longtime mean soil moisture is derived by using precipitation, soil texture, vegetation density and terrain slope. In a second step, the temporal variability at each location is deduced by using microwave radiation measurements available from satellite together with precipitation and air temperature data. This soil moisture algorithm is applied in Northern and Central Europe to validate a climate simulation from the regional model REMO.
Evaluation of the heat balance components over the Baltic Sea using four gridded meteorological databases and direct observations
Authors: Rutgersson A. , Omstedt A. , Chen Y.
Published: May 2018

In this paper, which reports on part of the BALTEX project, various components of the heat balance over the Baltic Sea are calculated using a number of gridded meteorological databases. It is the heat exchange between the Baltic Sea surface and the atmosphere that is of interest. The databases have different origins, comprising synoptic data, data re-analysed with a 3D assimilation system, an ocean model forced with gridded synoptic data, ship data and satellite data. We compared the databases and found that the greatest variation between them is in the long- and short-wave radiation values. However, considerable upward long-wave radiation is followed by considerable downward short-wave radiation, so the total radiation component is partly compensated for in the total budget. The variation in the total heat transport in the databases therefore appears smaller (1.5±3 W m−2) as the average and one standard deviation. The turbulent heat fluxes estimated from satellite data have very low values; this can largely be explained by the method of calculating air temperature, which also produces an unrealistic stratification over the Baltic Sea. The ERA40 data was compared with measured values: there, we found a certain land influence even in the centre of the Baltic proper. The indicated turbulent heat fluxes were too large, mainly in the fall and winter, and the sensible heat flux was too large in a downward direction in spring and summer.
Regional trend detection of Turkish river flows
Authors: Topaloğlu Fatih
Published: May 2018

This paper applies a procedure that identifies trends in hydrologic variables. The procedure utilizes the regional Mann–Kendall non-parametric test with and without both serial and cross-correlation to detect trends. The research investigates 15 streamflow variables including annual minimum, mean, maximum and monthly streamflows for a network of 75 streamflow gauging stations in seven geographical regions of Turkey. A considerable difference was obtained in the assessment of results with and without consideration of serial and cross correlation which might be due to a higher number of serial and cross-correlations among the sites in the geographical regions. Therefore, a quite different interpretation of these trend analyses would have been achieved if the temporal and spatial correlation of the streamflow series within the regions had been ignored. The application of the regional trend detection technique with both considerations has also resulted in the identification of significant decreasing trends in the Marmara, Aegean, Mediterranean and Central Anatolia regions. However, almost no evidence of significant change was observed with a general downward direction in the rest of the country. Besides, there are differences in the geographical regions of significant trends in the fifteen streamflow variables considered which implies that impacts on streamflows are not spatially uniform.
Evaluation of microbial source tracking methods using mixed fecal sources in aqueous test samples
Authors: Griffith John F. , Weisberg Stephen B. , McGee Charles D.
Published: May 2018

Microbiological source tracking (MST) methods are increasingly being used to identify fecal contamination sources in surface waters, but these methods have been subjected to limited comparative testing. In this study, 22 researchers employing 12 different methods were provided sets of identically prepared blind water samples. Each sample contained one to three of five possible fecal sources (human, dog, cattle, seagull or sewage). Researchers were also provided with portions of the fecal material used to inoculate the blind water samples for use as library material. No MST method that was tested predicted the source material in the blind samples perfectly. Host-specific PCR performed best at differentiating between human and non-human sources, but primers are not yet available for differentiating between all of the non-human sources. Virus and F+ coliphage methods reliably identified sewage, but were unable to identify fecal contamination from individual humans. Library-based isolate methods correctly identified the dominant source in most samples, but also had frequent false positives in which fecal sources not in the samples were incorrectly identified as being present. Among the library-based methods, genotypic methods generally performed better than phenotypic methods.
A systematic review of the health outcomes related to household water quality in developing countries
Authors: Gundry Stephen , Wright Jim , Conroy Ronan
Published: May 2018

In developing countries, the microbial contamination of household drinking water is implicated in the prevalence of various diseases. This systematic review is concerned with two health outcomes, general diarrhoea and cholera, and their relationship with water quality at point-of-use. Observational studies investigating this relationship are reviewed, as well as studies of home water treatment and storage interventions. For cholera, a clear relationship was found with contaminated water. Home water treatment and storage interventions were also found to reduce cholera. For general diarrhoea, no clear relationship was found with point-of-use water quality, although interventions did significantly reduce diarrhoeal incidence. Reasons for these apparently contradictory results concerning general diarrhoea are discussed and suggestions for further research offered. The policy implications of the findings are also discussed.
Diarrhoeal diseases in Nepal vis-à-vis water supply and sanitation status
Authors: Pokhrel Damodar , Viraraghavan Thiruvenkatachari
Published: May 2018

Diarrhoeal diseases are still a major challenge in Nepal because of inadequate safe water supply, poor sanitation and living conditions. However, several other factors such as the literacy rate, socio-economic status, and social, religious or personal perception of the cause of disease may influence the rate of morbidity and mortality of diarrhoeal diseases. A yearly minimum death of 30,000 and morbidity of 3.3 episodes per child was estimated due to diarrhoea. An environmental health education programme, along with water supply and sanitation intervention, is an effective mitigation measure to reduce diarrhoeal diseases in Nepal.
Development of a toolbox to assess microbial contamination risks in small water systems
Authors: Butterfield Phillip W. , Camper Anne K.
Published: May 2018

Individual and small water systems account for the majority of waterborne disease outbreaks recorded in the United States each year. To address this problem a project was undertaken to develop a comprehensive self-assessment toolbox that could be used by small water system personnel to determine where their system has the greatest potential risks from microbial contamination. The toolbox components consist of: (1) a survey that asks specific questions; (2) a ranking tool that computes numerical scores for water system components based on survey answers; (3) comments and results from the ranking tool; (4) a guidance document to help the user understand why certain conditions may represent a risk; and (5) instructions for using the toolbox. A unique feature of the ranking tool is the ability to input expert opinion in the form of scores for each answer and weighting factors. Weighting factors are derived using ranked, pairwise comparisons, and then used to determine numerical scores for system components. Toolbox administrators are allowed to modify weighting factors used by the ranking tool application, thus allowing input of expert opinion.
Aspects of health-related microbiology of the Subin, an urban river in Kumasi, Ghana
Authors: Obiri-Danso K. , Weobong C. A.A. , Jones K.
Published: May 2018

The aim of this study was to assess the influence of urban waste, sewage and other human centred activities on the microbiological quality of the river Subin, which flows through the metropolis of Kumasi, Ghana, and serves as drinking water for communities downstream. Three sites, Racecourse, Asafo and Asago, on the Subin were monitored over a year for total coliforms, faecal coliforms, enterococci and biochemical oxygen demand. Bacterial indicator numbers (geometric mean 100 ml−1) varied from 1.61 × 109 to 4.06 × 1013 for total coliforms, 9.75 × 108 to 8.98 × 1012 for faecal coliforms and 1.01 × 102 to 6.57 × 106 for enterococci. There was a consistent increase in bacterial loading as the river flows from the source (Racecourse) through Kumasi. Bacterial numbers were significantly (p≤0.05) higher during the rainy season compared with the dry (harmattan) season. The biochemical oxygen demand ranged from 8 mg l−1 at the source of the river to 419 mg l−1 at Asago; none of the sites achieved internationally accepted standards for water quality. The River Subin becomes grossly polluted as it flows through Kumasi and at Asago, a rural community downstream of Kumasi that abstracts water from the river for drinking, this probably contributes to the observed high levels of diarrhoeal disease.
Microbiological assessment of ambient waters and proposed water sources for restoration of a Florida wetland
Authors: Betancourt W. Q. , Rose J. B.
Published: May 2018

This study evaluated the microbial quality of reclaimed and storm water as proposed sources for restoration of a Florida wetland. Bacterial indicators, bacteriophages and waterborne pathogenic microorganisms (Cryptosporidium, Giardia and infectious enteric viruses) were analysed during a 1-year period in order to determine potential public health risks associated with exposure to the proposed water sources for restoration. Ambient waters within the wetland (four active water wells and four major lakes) were included in the study in order to determine the microbial water quality before restoration. Storm water and lakes had the highest level of microbial contamination. Much lower levels of microbial indicators and waterborne pathogens were found in reclaimed water and groundwater. Pathogen occurrence in groundwater was intermittent. Owing to the small percentage of source waters (3.3%) migrating to the water wells, ambient concentration of microbial constituents in surface and groundwater could dominate microbial risk. The results of this study indicate that, in the light of the uncertainties involved in computing average Cryptosporidium concentrations, additional characterization of the current ambient water quality should be ongoing prior to restoration.
Seasonal virus removal by alternative onsite wastewater treatment systems
Authors: Axler Richard P. , Henneck Jerald R. , McCarthy Barbara J. , Hicks Randall E. , Olson Matthew R.
Published: May 2018

Viral contamination of public waters is a leading health concern around the world, including in Minnesota where cold climate, abundant onsite systems on poor or thin soils, and abundant surface water resources present a significant risk of wastewater pathogens reaching sensitive water sources. Three alternative onsite treatment systems, a sand filter, peat filter and subsurface-flow constructed wetland (CW) at a field research site were evaluated for seasonal virus removal by seeding each with MS2 bacteriophage. The sand and peat filters and CW removed 2.7, 7.0, and 1.4 log10 of MS2, respectively, during summer and 1.8 and 6.9 log for the sand and peat filter during winter (CW not seeded). Somatic coliphage reductions for the sand filter, peat filter and CW were 2.9, 3.5, 1.0 log10 in summer, and 1.5, 2.8, 0.7 log10 during winter, respectively over a 3 year period. During this period, fecal coliform log10 reductions were 2.9, 4.6, 2.0 in summer for the sand and peat filters and CW, and 2.0, 4.6, 1.6 in winter. The peat filter was the most effective system for removing MS2, somatic coliphage and fecal coliforms during both winter and summer but all systems removed >90% of viruses throughout the year.
Better intervention strategies are needed to reduce the risk of waterborne outbreaks
Authors: Geldreich Edwin E.
Published: May 2018

Field investigation of 27 medium to small water systems in Ontario Province has revealed a pattern of deviations in operations that is similar to those reported in the United States over the past 25 years. In this recent Ontario survey of water utilities, the key findings were: (1) a need for full cost pricing of public water supply to consumers; (2) better understanding of water treatment train performance; and (3) a need for management driven accountability to search beyond regulatory minimum requirements for safe water quality. Much of the deteriorating state of operations was a reflection of limited financial base to support an effective management programme. In the survey, small utilities were found to suffer the most from below cost operations which forced the application of a patchwork approach to water treatment and system repairs. Furthermore, small system water plant operators had rare opportunities to take part in workshops on technical issues. These utilities need to partner with the public on water supply issues for financial support to cover daily operations, infrastructure decay and emergency repairs. Ignoring system problems or applying patchwork remedies will eventually lead to unsafe water quality if the current state of affairs is not recognized as a dangerous public health risk.
Bottled water versus tap water: understanding consumers' preferences
Authors: Doria Miguel F.
Published: May 2018

The consumption of bottled water has been increasing consistently over the last decade, even in countries where tap water quality is considered excellent. This paper discusses some of the reasons why people decide for an option that is often more expensive and less comfortable than tap water. Consumer surveys usually stress two main factors: dissatisfaction with tap water organoleptics (especially taste) and health/risk concerns. However, many other factors are involved, including demographic variables and the perceived quality of the water source. Trust in tap water companies also seems to influence public behaviour. A clearer picture of bottled water consumption can be achieved when different aspects are considered.
Drinking water consumption patterns in Sweden
Authors: Westrell Therese , Andersson Yvonne , Stenström Thor Axel
Published: May 2018

Estimates on drinking water consumption are necessary in risk assessments on microbial hazards in drinking water. Large differences in consumption habits between countries have been reported. In order to establish estimates for the Swedish population, water consumption data from a waterborne outbreak investigation (157 people), a small water consumption study (75 people) and a large study on health and environmental factors (10,957 people) were analysed. A lognormal distribution for the daily direct/cold water intake in litres with μ=−0.299 and σ=0.570 was fitted to the quantitative data, representing the general population. The average daily consumption of tap water as plain drinking water and as heated tap water, e.g. in coffee and tea, was 0.86±0.48 l and 0.94±0.69 l, respectively. Women consumed more cold tap water than did men, while men appeared to have a higher consumption of heated tap water. Cold tap water intake was highest in the oldest age group, (≥70 years). The consumption of bottled water was very low (mean 0.06 l/d) when compared to other countries.
Research needs in drinking water: a basis in regulations in the United States
Authors: Jacangelo Joseph G. , Askenaizer Daniel J. , Schwab Kellogg
Published: May 2018

Regulations are one of the primary drivers for research on contaminants in drinking water in the United States. Since the original Safe Drinking Water Act (SDWA), enacted in 1974, the United States Environmental Protection Agency (USEPA) has developed a series of drinking water regulations. These regulations are focused on protecting public health. When evaluating available information on whether or not to regulate a constituent in drinking water, USEPA considers available information on health effects and occurrence of the constituent. The authors provide their view of the research needed for these contaminants. For inorganics, more data are needed on perchlorate. For organics, greater treatment and health effects information is warranted for N-nitrosodimethylamine (NDMA), methyl tertiary butyl ether (MTBE) and pharmaceuticals and personal care products. Finally, more research is needed on analytical methods for noroviruses and other emerging pathogens.
The challenge of public participation
Authors: Mostert Erik
Published: May 2018

Public Participation (PP) has gained widespread recognition as a key water management principle. Despite this, the practical application of PP remains problematic. This article presents the current state of developments in PP theory and practice. It discusses the benefits of PP and gives many suggestions for making PP more effective. It pays special attention to the place of PP in democratic theory, to the cultural context of PP, and to its application in international river basins. This article concludes that PP should not be regarded simply as an accessory in aiding water management. Effective PP is, in fact, an entirely different mode of governance.
The introduction of water resources management programs in Western Asia
Authors: Jurdi Mey , Abdulrazzak Mohamed J. , Basma Shiraz
Published: May 2018

This paper emphasizes the importance of developing and implementing integrated water resource management programs in the Western Asia region. As such, the status of water resources management programs is assessed in reference to the integrative components of water policies and strategies, water legislation and enforcement, water institution framework, and water resource assessment and capacity building. Besides, recommendations relative to the hereby indicated integrative components are proposed where applicable. Development and implementation of an integrated water resources management program is essential for the region to overcome existing programs that are mainly oriented towards demand management and exploitation of groundwater reserves. Such programs would be directed to satisfy national freshwater needs for development and to promote water as an integrated component of social and economic goals as well as ecosystem management.
Water resources management of the Yellow River and sustainable water development in China
Authors: Shucheng Wang
Published: May 2018

China is a country frequently hit by floods and droughts. Managing water resources and minimizing the losses caused by water disasters has always been among the most important issues faced by the Chinese government in governing the state. In recent years, to tackle the water problems in China and to meet the requirement of sustainable economic and social development, we have actively pursued sustainable water development. Thinking about water management has thus been greatly modified and remarkable achievements have been made accordingly.

The Yellow River, known as the Mother River of China, is the cradle of Chinese civilization, whose problems can represent that of most Chinese rivers. Citing the Yellow River management in recent years as an example, this paper elaborates the strategy of sustainable water development in China.
Can development of water resources reduce poverty?
Authors: Rijsberman Frank
Published: May 2018

The United Nations Millennium Declaration and resolutions at the 2002 World Summit on Sustainable Development give high priority to poverty reduction in international development agenda for the next decade and a half. It is now widely recognized that water resources development and management play a fundamental role in sustainable growth and poverty reduction. However, investments in water resources development, which were considered a high priority by governments and aid agencies for decades, have fallen drastically. The key question addressed in this paper is: Can water resources development reduce poverty? It examines the impacts of past investments on water resources development and management, (especially on irrigation), on poverty reduction. It is shown that past investments in irrigation development have made a significant contribution to alleviating poverty. In recent years investments made by private farmers in groundwater irrigation may have had a larger impact on livelihoods for poor people than the public investments in large-scale surface water irrigation systems. It is argued that there is not a single silver bullet to reduce poverty though water resources development or management. The best chance for lasting and sustainable impact on poverty is likely to be achieved through a combination of sustainable water resources development, combined with the development of appropriate pro-poor institutions and technologies.