bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial Variability of Physical Parameters and Processes in Two Field Soils
Authors: Høgh Jensen K. , Refsgaard J. C. 
Published: May 2018

Natural field systems exhibit a large degree of soil heterogeneity which affects the movement of water and solutes and thus leads to highly varying observations of water content and solute concentration. To investigate this problem comprehensive field investigation programs were carried out at two field sites in Denmark representing two different soil types, a coarse sand and a sandy loam, respectively.
The field investigations included collection of soil samples for analysis of textural composition, retention, and hydraulic conductivity, measurements of water content and suction, and measurements of radioactive tracer concentration, all carried out at a number of positions within the two field sites.
Models for one-dimensional vertical unsaturated flow and solute transport were applied to the two field sites, and the simulation results were compared to field measurements of water content, suction and solute concentration. This paper describes results from model simulations in individual soil profiles, while the variability issues at field scale are described in the two accompanying papers. The modelling approach was based on numerical solutions to Richards' equation for water flow and the convection-dispersion equation (CDE) for solute transport. The model results from the coarse sand field site compared relatively well to measurements of water content, suction, and concentration except for the upper soil layer (∼ 10 cm depth) where the measured water contents appeared to be somewhat uncertain.
Due to the neglecting of hysteresis and macropore flow (by-pass) in the model the measured retention curves (drainage based) and the hydraulic conductivity functions at the sandy loam field site had to he modified empirically through the calibration procedure in order to match the measurements.
Analysing Hydrometeorological Time Series for Evidence of Climatic Change
Authors: Kite Geoff 
Published: May 2018

Considerable scientific attention has been focused on a measured increase in atmospheric CO2 and a suspected corresponding change in climate. Such a change in climate, if it occurred, might be expected to have a magnified effect on hydrologic time series and, indeed, projections have been made of major changes in water resources.
If the climatic changes are indeed magnified in hydrologic time series then, by detecting trends in such series, it should be possible to work backwards and identify the causative climatic change. This paper looks at two data sets: 1) long-term temperature, precipitation and streamflow data from sites across Canada and 2) long-term levels of large lakes in Africa and North America.
The study assumes that time series may be modelled by trend, periodic, autoregressive and random residual components. The trend component of a time series is generally associated with changes in the structure of the time series caused by cumulative natural or manmade phenomena. Periodicities in natural time series are usually due to astronomical cycles such as the earth's rotation around the sun. Autoregressive components reflect the tendency for an event to be dependent on the magnitude of the previous event(s), a memory effect.
The analyses of temperature, precipitation and streamflow data show some significant linear trends but no pattern is apparent. The analyses of longterm lake levels also identify linear trends but these are all explainable without invoking climate change due to greenhouse gases.
The Effect of Riverine Nitrate Loads on Winter Concentrations in the Great Belt, Denmark
Authors: Jürgensen Carsten , Tornbjerg Niels Henrik 
Published: May 2018

This paper presents a method that models the fraction of the NOx concentrations (nitrate and nitrite) in a marine recipient resulting from riverine runoff from land. The analysis is performed on the surface waters in the Great Belt, Denmark, during winter seasons. The method is based on simulation of two independent NOx fractions: First, the “background” fraction, which results from the oceanographic mixing in the Belt Sea between Kattegat water and Baltic Sea water, and second, the nutrient load from land. The calculation of the background fraction is based on the finding that the Kattegat water has high salinity and high NOx contents whereas the Baltic Sea water has low salinity and low NOx contents. By means of an empirical relation between salinity and NOx a specific salinity measurement in the mixing zone can be related to a “background” NOx concentration. Measurements in the Great Belt show to be higher than the calculated “background” concentrations, which indicates the presence of a second NOx fraction. The second fraction is defined as the difference between the calculated background concentration and the measured NOx concentration. The hypothesis of the present paper is that this second fraction is dominated by the river runoff. Cross correlation analysis between the time series of the river NOx load and the time series of surplus concentration in the Great Belt reveals a time lag between maximum river load and maximum surplus concentration during winter seasons of approx. 1 month. An empirical transfer function has been developed in order to connect the daily NOx river loads with the surplus concentration in the Great Belt. The development of the NOx-concentration in the Great Belt due to river run off is modelled for 8 specific winter periods of 3 months (December - February) between 1988/1989 and 1995/1996.
The model simulates concentrations on a weekly basis and quantifies the NOx-increase during each winter based on the river load data. The analysis indicates that the NOx concentration can be doubled during winters with high runoff, giving rise to an increase of approx. 60 μgN/1 at the end of February. In winters with minimal runoff no significant increase above the background level is found.
Nitrogen Concentrations Simulated with HBV-N: New Response Function and Calibration Strategy
Authors: Pettersson Anna , Arheimer Berit , Johansson Barbro 
Published: May 2018

HBV-N is a conceptual process-based model for simulation of transformation and transport of nitrogen on the catchment scale. This paper presents further development with focus on the response function and calibration procedures. Evaluation of the model routines was made in 12 test basins in southern Sweden (without or with only few lakes). Previous versions of HBV-N included a HBV version with a single reservoir in the response function. The presented results show that both nitrogen concentrations and water discharge simulations improved when a second reservoir was introduced. The two-reservoir model was found to be more well-posed for description of residence-times and flow paths. On average, this resulted in an increase in explained variance (R2) for nitrogen concentrations by 0.3.
Multiple-responee split-sample calibration was found to further improve the model performance and reliability. In previous applications HBV-N has been applied by using single-response calibration. However, simultaneous calibration of water discharge and nitrogen improved the R2 for nitrogen concentrations by about 0.1 (range 0.02-0.25), but did not affect the simulation of water discharge. This new calibration strategy forces the hydrological parameters to a new optimum, and reduces the level of uncertainty for both hydrochemical and hydrological modelling.
Seasonal Water Balance of an Alpine Catchment as Evaluated by Different Methods for Spatially Distributed Snowmelt Modelling
Authors: Zappa M. , Pos F. , Strasser U. , Warmerdam P. , Gurtz J. 
Published: May 2018

The application of three temperature-index based models and of one energy balance based snowmelt model was investigated. The snow models were integrated in the spatially distributed hydrological model PREVAH. In this study the hydrological simulations of the alpine catchment of the Dischmabach in Switzerland in the period 1982-2000 have been analyzed. The PREVAH model was driven by hourly interpolated meteorological data.
All snowmelt approaches allowed a good simulation of the discharge regime and of the seasonal course of the snowpack. The highest model efficiency was obtained by a radiation based temperature-index approach. A simplified energy balance approach combined with the positive degree-day method showed a very similar performance to the classical positive degree-day approach. The energy balance approach ESCIMO showed a high performance variability from year to year.
The dependency of the seasonal water balance with respect to altitude is also discussed in this report. The quality of the spatially distributed reproduction of periods with positive and negative water balance (snow accumulation and snowmelt) is crucial for the correct simulation of the runoff hydrograph. The analysis shows that runoff maximum in the Dischmabach catchment is caused by a superposition of the main snowmelt season in the areas between 2,100-2,800 m a.s.l. and the period with maximum rainfall.
Lithuanian karst region rivers' water ecology: hydrochemical and hydrobiological evaluation
Authors: Tumas Rimvydas 
Published: May 2018

The Lithuanian karst region covers about 1000 km3 in the northern part of the country. This is the most vulnerable area from a pollution point of view. The structure of the total dissolved solids (TDS) shows that the flow of rivers in the karst region is from hydraulically interconnected aquifers. For the last decade (1991–2000) TDS has varied considerably, from 529 to 732 mg/l. The predominant sources of nitrogen and phosphorus within the headwaters of the monitored rivers were diffuse and agricultural in nature. Downstream from the towns nitrogen and especially phosphorus showed both diffuse and point source signals. Contributions of point sources to the stream pollution by nutrients prevail.
The time series of monthly dissolved oxygen (O2) in the main karst region river – the Musa – shows the existence of multiplicative seasonality. The trend cycle (1991–1999) shows low levels of dissolved oxygen in 1991–1993, with a similar fluctuation in 1994, 1995 and 1996 (due to point pollution from the town of Siauliai) and a gradually improving situation since 1997. The general multiplicative trend of dissolved oxygen in the lower reaches of the Musa river (near the border with Latvia) is decreasing (within the accuracy limits).
The abundance and species of zoo benthos are suitable criteria (biotic index – BI) for evaluation of a river's biological water quality. Zoo benthos demonstrates tolerances that vary among species, the oxygen regime and the pollution with nitrogen. The best living conditions for invertebrates are in the riverhead of the karst region rivers – BI=5.62–6.74 (1991–1999), where pollution with nutrients is caused mostly by agricultural activity. Rare and asynchronous data of biological water quality shows up tendencies that invertebrates prefer less contaminated reaches of rivers.
Chlorination by-products (CBPs) in drinking water and adverse pregnancy outcomes in Italy
Authors: Aggazzotti Gabriella , Righi Elena , Fantuzzi Guglielmina , Biasotti Barbara , Ravera Gianbattista , Kanitz Stefano , Barbone Fabio , Sansebastiano Giuliano , Battaglia Mario Alberto , Leoni Valerio , Fabiani Leila , Triassi Maria , Sciacca Salvatore ,   Collaborative Group for the Study of Chlorinated Drinking Waters and Pregnancy
Published: May 2018

Chlorination by-products (CBPs) in drinking water have been associated with an increased risk of adverse pregnancy outcomes, including small for gestational age at term (term-SGA) and preterm delivery. Epidemiological evidence is weakened by a generally inaccurate exposure assessment, often at an ecological level.
A case control study with incident cases was performed in nine Italian towns between October 1999 and September 2000. A total of 1,194 subjects were enrolled: 343 preterm births (26th–37th not completed week of pregnancy), 239 term-SGA (from 37th completed week, and weight less than the lowest 10th percentile) and 612 controls. Exposure was assessed both by applying a questionnaire on mothers' personal habits during pregnancy and by water sampling directly at mothers' homes.
Levels of trihalomethanes (THMs) were low (median: 1.10 µg l−1), while chlorite and chlorate concentrations were relatively high (median: 216.5 µg l−1 for chlorites and 76.5 µg l−1 for chlorates). Preterm birth showed no association with CBPs, while term-SGA, when chlorite levels ≥200 µg l−1 combined with low and high levels of inhalation exposure are considered, suggested a dose-response relationship (adjusted-Odds Ratios (ORs): 1.52, 95%CI: 0.91–2.54 and 1.70, 95%CI: 0.97–3.0, respectively). A weak association with high exposure levels of either THMs (≥30 µg l−1), or chlorite or chlorate (≥200 µg l−1) was also found (adjusted-OR: 1.38, 95%CI: 0.92–2.07). Chlorine dioxide treatment is widespread in Italy; therefore, chlorite levels should be regularly and carefully monitored and their potential effects on pregnancy further evaluated and better understood.
Mapping global water projects: improving access to donor investment information on the web
Authors: Jorgensona J. Lisa 
Published: May 2018

This paper discusses a series of discusses how web sites now report international water project information, and maps the combined donor investment in more than 6000 water projects, active since 1995.
The maps show donor investment:
• has addressed water scarcity,
• has improved access to improvised water resources,
• correlates with growth in GDP,
• appears to show a correlation with growth in net private capital flow,
• does NOT appear to correlate with growth in GNI.
Evaluation indicates problems in the combined water project portfolios for major donor organizations:
•difficulties in grouping projects over differing Sector classifications, food security, or agriculture/irrigation is the most difficult.
• inability to map donor projects at the country or river basin level because 60% of the donor projects include no location data (town, province, watershed) in the title or abstracts available on the web sites.
• no means to identify donor projects with utilization of water resources from training or technical assistance.
• no information of the source of water (river, aquifer, rainwater catchment).
• an identifiable quantity of water (withdrawal amounts, or increased water efficiency) is not provided.
• differentiation between large scale verses small scale projects.
Recommendation: Major donors need to look at how the web harvests and combines their information, and look at ways to agree on a standard template for project titles to include more essential information. The Japanese (JICA) and the Asian Development Bank provide good models.
The French model of water supply management challenged by users' empowerment
Authors: Pflieger Géraldine 
Published: May 2018

Since the early 1990s, in France, the increase in water prices and the denunciation of public–private partnerships have encouraged the state, water companies and local authorities to enhance management transparency and develop their relationships with consumer groups. The opening to user representatives is challenging the French model of water supply management. These transformations are resulting in tensions between different representations of users as consumers or citizens. Between consumer and citizen, which representation is actually emerging and how is the user's status affected?
At the national level, the state and consumer groups tend to develop a pro-consumerist policy involving reflection on price levels, the efficiency of utilities and consumer information. On the other hand, companies are trying to highlight the representation of the citizen concerned about the environment and water quality. At the local level, user status varies with context. The user can be perceived either as a simple consumer or as a citizen–consumer hybrid. The examples of Grenoble and Ardèche show that consumption issues can be open to debate about public choices, investment strategies or drinking water quality. This opening up of debate depends on local authorities' competence and communication strategies, consumer groups' agendas and specific local issues (e.g. resource scarcity, corruption).
The application of new technologies in the water treatment process of a modern waterworks
Authors: Hoyer O. , Clasen J. 
Published: May 2018

The new plant for the treatment of water from the Wahnbach-reservoir went into operation at Siegburg, Germany in 2001. It will have a capacity of 3,600 to 4,800 m3/h and is intended for drinking water supply of the Bonn region. The relatively simple water treatment process achieves its high performance and safety from the sophisticated process layout and control developed from 40 years of research and experience at the Wahnbach Reservoir Association.
According to temporal needs permanganate and/or powdered activated carbon can be applied for pretreatment. Flocculation is either possible with Al3+- or Fe3+-salt solutions introduced by optimized flash-mixing and destabilization. Immediately afterwards at the inlet into the 12 aggregation and filtration trains it is possible to inactivate motile planktonic organisms by means of cavitation fields generated by ultrasound at 40 kHz. In the following aggregation step flocs are generated tailored to optimum retention in the double media filters which are regenerated via high speed build-up backwashing. Release of plankton and microorganisms accumulated in the filter bed by motile plankton is inhibited by the ultrasound treatment.
A continuously high filtrate quality is achieved by stacked filter-runs of the 12 filters adapted to the water quality with backwashes graded at equal time intervals after identical filter-run times, a filter to waste period after backwash first filtrate separation and permanent turbidity monitoring at the individual filtrate outlets.
Disinfection is achieved with 3 closed UV-systems equipped, performance tested and certified according to the DVGW technical standard W 294 and is followed by conventional. de-acidification with addition of lime water. The paper will describe and explain the process concept which has been worked out and validated by WTV within the framework of several research projects.
Monitoring for Cryptosporidium risk: do particle counters help?
Authors: Morse A. , Wilson R. , Hull A. , Simms J. 
Published: May 2018

Turbidity measurements are used extensively for monitoring water quality, and as a warning for process failure which may carry a risk of Cryptosporidium breakthrough. However, turbidity is most sensitive to particles in the submicrometre size range, whereas Cryptosporidium is 4-6 μm in diameter. The question therefore remains - do particle counters help in monitoring for the risk of Cryptosporidium breakthrough?
A full year study was undertaken at a direct river abstraction works. The project aimed to establish whether particle counts can be used to predict an increased risk of Cryptosporidium breakthrough. Although protozoan (oo)cysts were often present in low numbers in the raw water, none was detected in the final water. Particle counts and turbidity measurements were carried out on three RGFs and the raw and clarified water. Online Cryptosporidium and Giardia samples were also taken daily from the three RGFs being monitored for particles, and bacteriological analyses were carried out on the same sample points. Other plant parameters and environmental factors were also monitored.
Particle counts from RGFs varied significantly. The main factors influencing the filtered water particle count appeared to be raw water turbidity and algal counts, and the particulate loading rate to the filters.
Co-operation of private water management sector with municipalities
Authors: Kyncl M. 
Published: May 2018

After 1990 a gradual privatisation of the water and sewerage sector began in the Czech Republic as well as in other Central and Eastern European countries. State assets of public water pipelines and sewerage were transferred to towns and municipalities and joint stock companies were established. Two types of companies appeared Ð operational and ownership companies.
The first type is the operational company that operates the infrastructure assets of public water pipelines and sewerage. These assets stay in the ownership of municipalities. A long term operational contract is agreed that solves the relationship between the owners and operators.
The second type is the ownership company that directly owns the infrastructure assets of public water pipelines. Towns and municipalities in this case became shareholders of those companies. At the end of nineties, big international companies bought shares of both operational and ownership companies. Municipalities have to, by law, ensure the operation of public water pipelines. However, by the sale of shares they have lost a possibility to participate in decision making.
A question about future co-operation between towns and municipalities and ownership companies appears. An example of the North Moravian Water and Sewerage Works Company was used to describe a possible way of co-operation between a private company and the municipalities on whose territory the company operates. Contracts between the ownership company and particular municipalities were agreed. This solution turned out to be complicated, so the municipalities affiliated and established Water Management Association. The objective of the Association is to promote common interests of the municipalities in relation to the water company. A contract was agreed between the Water Management Association and the company about co-operation in the area of water tariff setting and public waterworks' development.
“Jan-Lagrand” water treatment works: UF/RO from technological novelty to full size application
Authors: de Bruijn F. , Kamp C. , Eddy D. , Kools J.E. 
Published: May 2018

In Heemskerk the world's largest dual membrane municipal water treatment works ( WTW) “Jan-Lagrand” (55 Ml/d or 2,250 m3/h or approximately 15 MGD) was commissioned at the end of 1999. At Heemskerk WTW, pretreated surface water is subsequently treated by ultrafiltration (UF) and reverse osmosis (RO). The RO permeate is directly blended into drinking water without chemical disinfection.
Before Heemskerk the dual membrane concept had not been considered on this scale, and during project preparation numerous developments and innovations needed to be flexibly accommodated into the ongoing design. Conceptual system development, pilot research and design and engineering were successfully conducted “in parallel”.
This paper deals with the innovations that were materialized in Heemskerk, e.g. UF-membrane pretreatment, on line membrane integrity testing (UF and RO) for disinfection approval, and a dual floor building concept for membrane installations. This paper explains how these innovations could be accommodated into an ongoing design, while innovative testing was still proceeding.