bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acidification in 50 Norwegian Lakes
Authors: Økland Jan 
Published: May 2018

In 50 lakes in south-eastern Norway hydrogen-ion concentration (pH) and total hardness (°dH) were measured in surface water in the 1950's and then once again 10 years later. Significant acidification was observed. In the total material average pH dropped from 7.0 to 6.8. The lakes were grouped into a low-total-hardness (0-l°dH) and a high-total-hardness group (&gt;l°dH). [l°dH = 10 mg »CaO«/l]. In the low-total-hardness group average pH had dropped from 6.6 to 6.3 and the average H+ concentration increased with 4.33. 10−7 mol/1. In the high-total-hardness group significant acidification could hardly be traced. The data confirm previous observations that also lakes which in previous years had pH close to the neutral point have become acidified. Total hardness showed no significant change.
Acidification seems to occur most frequently in lakes with total hardness ⩽l°dH. Such lakes are present all over Norway and are dominant in many areas.
Diversion of the River Neva
Authors: Pedersen Flemming Bo , Møller Jacob Steen 
Published: May 2018

Diverging part of the river Neva discharge to the dry regions in the southern USSR has raised the question, to what extent such a river diversion will influence the hydrographic conditions in the Baltic Sea and the Danish Inland waters. In order to quantify the influence, the system has been divided into eight subareas, each of which is characterized by an equation for the mass, the volume and the dynamic balance (the mixing), respectively. The man-made change in the river runoff has been introduced in the equations, which have then been linearized and solved with respect to changes in the salinities, the discharges and the layer depths in the system.
As a quantitative example the hydrographic consequences of a 25% reduction in the river Neva discharge have been outlined. The most pronounced influence is on the salinities, which are increased by 0.2 to 0.4 ‰ allover in the system. Hence, if the river diversion had become executed in the beginning of this century a 30 to 40% higher salinity-variation would have been encountered in the Baltic Sea – compared to the actual variations during this century.
Extreme Rainfall Events in Lund 1979–1980
Authors: Niemczynowicz Janusz , Jonsson Olle 
Published: May 2018

All raingauge measurements give only one-point values. Since the practical applications of rain data always deal with areal measures, the knowledge of areal distribution of rain is very important for correct evaluation of the rain volumes. Two types of rainfall input data are generally used: design rainfall hyetographs and long historical rainfall records. The third type of input data has to be recognized: the observed single rainfall event, during which the consequences such as runoff, flooding or pollution loads have been observed and recorded. Good areal characterization of such single event is necessary if the results are to be generalized.
In the paper a set of extreme rainfall events observed in Lund during a period of two years is presented. Point and areal intensities are presented for ten extreme events. Storm centered Areal Reduction Factors (AFR-s) calculated for different durations are also presented. Size, shape and movement of the raincells is discussed in the context of the meteorological background observed.
A Numerical Model of Aquifer Tests in Multi-Layered Aquifer/Aquitard Systems
Authors: Mucha Igor , Kærgaard Henrik 
Published: May 2018

A numerical model is presented, capable of computing drawdowns anywhere in a multiaquifer/aquitard system, resulting from pumping from a single well, screened in arbitrarily chosen aquifer(s) in the system. The model is of radial, symmetric type, in the sense that inhomogeneities in horizontal directions cannot be taken into account. The model was created primarily to compute the effects of any kind of stratification in an aquifer system on the results of pumping tests.
The computing principles are described, and drawdowns in a hypothetical system are computed to be compared with standard aquifer test formulas in order to illustrate the behaviour of the system.
The model is finally used for interpretation of two earlier reported aquifer tests from localities in Denmark.
Runoff Chemistry at a Mini-Catchment Watered with “Unpolluted Precipitation”
Authors: Christophersen N. , Stuanes A.O. , Wright R.F. 
Published: May 2018

600 mm of artificial, “unpolluted” precipitation with a chemical composition of assumed preindustrial quality ([H+] = 9 μeql−1, [SO4] = 11 μeql−1) was sprayed on a “mini-catchment” (98 m2) over a period of 3½ weeks. The mini-catchment is a granitic bowl partially covered with shallow, acid soils. It is located in the Storgama area, Telemark county, southern Norway, an area which today receives acidic precipitation ([H+] = 54 μeql−1, [SO4] = 59 μeql−1).
The treatment resulted in lowered values for [H+], [Al] and [SO4] in runoff within a week. Excluding the spring snowmelt, [H+] ≈ 50 μeql−1 (pH = 4.3) under natural conditions, whereas during the experiment [H+] levelled off at 30 μeql−1 (pH = 4.5). Correlation analysis suggests that SO4 and organic anions are related to the runoff acidity. The level of total organic carbon in runoff was, however, elevated compared to undisturbed conditions. Under the present natural conditions S04 is the most important anion.
The amount of water-extractable sulfate in the soil is equivalent to about ½ of the present yearly input. The response in the sulfate output to a reduced input is difficult to predict because of processes which transform sulfur to and from various compounds in the soil and vegetation. Several years may be required before a new steady state is reached after a substantial decrease in input. Long-term experiments in which the catchment is shielded against natural precipitation are required to obtain more certain estimates of the response in runoff composition.
A New Technique for the Analysis of Extreme Rainfall with Application to Lagos Metropolis, Nigeria
Authors: Oyegoke E. S. , Sonuga J. O. 
Published: May 2018

This paper focuses on the use of the principle of maximum entropy as an alternative technique for the parameter estimation of the Extreme Value Type – 1 (EV1) distribution or Gumbel distribution often used for the analysis and forecast of extreme events. A case study is made of storm rainfall analysis for Lagos metropolis using the available rainfall data for Ikeja, Oshodi and Lagos Mainland as obtained from Akanbi (1982).
For comparison purposes, the parameters of the EV1 distribution is also obtained using the Maximum Likelihood Method. The later being one of the most reliable techniques and perhaps the most widely used for parameter estimation of the EV1 distribution. This exercise has made it possible to demonstrate in some ways the superiority of the maximum entropy method over existing methods used for statistical simulation of extreme events.
A Study of Soilwater and Groundwater Flow of Hillslopes – Using a Mathematical Model
Authors: Johansson B. 
Published: May 2018

The soil and groundwater flow of a hillslope adjacent to a stream has been studied using a physically based mathematical model. Values of soil parameters have been taken from investigations of Swedish till soils. Model simulations have been made in order to calculate groundwater outflow during and after a rainfall event, and to study the response to infiltration of soil and groundwater flow in different parts of the slope. The effects of soil layering and slope configuration have also been studied.
The simulated peak of groundwater outflow, occurring just after cessation of infiltration, is of the same order of magnitude as a typical streamflow peak in a small Swedish watershed. The increase of groundwater outflow during and after a rainfall event is, according to model simulation, caused by infiltration close to the stream. Hence, the soil properties of this part of the slope are of great importance to runoff generation.
Hydrological Maps Development of a System for Calculation and Presentation
Authors: Johansson B. , Jutman T. 
Published: May 2018

Increasing attention is paid to problems concerning water resources planning. It is essential that the hydrological information required is available to the planner in a form that facilitates combination with other types of information.
This paper describes the development of a system for calculation and presentation of regional and comprehensive hydrological information. Main components of the system are the interpolation routines, a water balance model adapted to the space and time scale and a data base for supporting information. Examples of presentations are given.
Modelling of Unsaturated Flow in Heterogeneous Soils
Authors: Høgh Jensen K. 
Published: May 2018

Water flow and solute transport in the upper soil layers are processes which are of importance in many hydrological and agricultural applications. These processes are occurring in a medium which has a complex composition, since the soil is a product of both the geological formation history and various man-induced activities like agricultural development. In addition, the upper soil is subject to cyclic variations in water content in response to the variable exposure of rainfall and outer evapotranspiration demand.
The paper describes simulations of the field conditions at different points within two research fields where comprehensive field investigations have been carried out. The simulations are based on solutions to the partial differential flow equation, subject to the measured climatic conditions and the hydraulic properties in the individual soil columns. The simulations of water content and capillary pressure are compared with measurements.
Transformation of Input to a Stochastic Model using a Distributed Deterministic Model
Authors: Snorrason Á. , Einarsson K. 
Published: May 2018

In recent years, hydrologists have attempted, with encouraging results, to synthesize the accomplishments of time series analysis and deterministic systems methods into the more general framework of stochastic dynamic systems. The purpose of this paper is to attempt an improvement of a stochastic time series model by the use of inputs generated by a distributed, deterministic model.
The analysis is based on a simplified transfer function-noise model, where the system output is modeled as a linear combination of present and past inputs as well as past outputs.
The systems chosen for the analysis are two partially glaciated basins in Iceland.
The results were in general promising and showed that a careful selection of input series could overcome to a great extent the non-linearities as well as the non-stationarities in the relationship between discharge and meteorological variables. The results also showed that transformation of the meteorological series using distributed, deterministic techniques gave superiour results, compared with the standard degree-day approach.
Snow Distribution on Forest Clearcuts in the Swedish Mountains
Authors: Zakrisson Kurt-Åke 
Published: May 2018

The paper is focused on the problem of choosing observation localities at the margin of forests for snow surveys. A systematic study was made of differences in snow depth and water equivalents of snow accumulation near the boundaries between forests and open land. The field data were collected during the winter seasons 1983-84 and 1984-85.
The study involves sounding snow depths and calculating water equivalents of the snow cover from profiles crossing distinct boundaries between forests and clearcuts. The snow accumulation was found to be relatively large in a zone up to 40 m just outside the forest boundary. The accumulation up to 15 m just inside the forest boundary was relatively small as compared to the forest in general.
A slight excess of snow in the forest compared to the clearcuts, established at the beginning of the snow accumulation season, gradually turns into a small deficit in April. During most of the melting season the amount of snow in the forest is considerably bigger than in the clearcuts.
Proposed Swedish Spillway Design Guidelines Compared with Historical Flood Marks at Lake Siljan
Authors: Harlin Joakim 
Published: May 2018

A comparison between the proposed Swedish spillway design floods and historic flood marks made at lake Siljan in central Sweden, is shown. Frequency analysis is performed incorporating pregauge information on water levels together with a sensitivity analysis of modelling assumptions.
A water level of 0.42 to 0.75 metres above the highest historic flood mark (166.10 m.a.sl., 1659) was obtained when routing the design spring flood through lake Siljan. The design autumn flood lifted the lake to 1.56 to 1.52 metres below the highest flood mark. Return period for the design spring and autumn flood was estimated to about 1,000 years. The uncertainty in frequency analysis proved to have larger impact than modelling assumptions on estimating the risk of the design flood.
Equilibrium Speciation Models for Hg, Cd, and Pb in the Gulf of Bothnia and its Catchment Area
Authors: Gunneriusson Lars , Sjöberg Staffan 
Published: May 2018

Equilibrium speciation models were established for Hg (II), Cd (II) and Pb (II) in bog-, river- and sea water having a composition corresponding to that of the Gulf of Bothnia (6 ‰ salinity). The calculations were performed using the computer program SOLGASWATER. The models were based on available thermodynamic data at 25°C and included the inorganic ligands OH−, Cl−, Br−, HPO42− and CO2 (aq). Furthermore, complex formation with organic substances originating from a bog water was considered, Mg (II) and Ca (II) were also included as competing cations. All water types were assumed to be oxic and in equilibrium with atmospheric carbon dioxide, 10−3.5 atm (32 Pa).
The calculations showed that the speciation of Hg (II) and Pb (II) in bog and river waters is dominated by complexation with the organic substance, except for lead (II), where the Pb2+ -ion dominates at pH⩽5. In the Gulf of Bothnia, the chloro complexes HgCl2 and HgCl3− becomes prevailing as the salinity increases. Besides Pb2+, the species PbCl+ and PbCO3 become important upon increasing the salinity and pH. The dominating fraction of Cd (II) is Cd2+ in bog water, in river water and in waters of salinity lower than 4.5 ‰.
With increasing salinity CdCl+ and CdCl2predominate.
Spatial Variability of Physical Parameters and Processes in Two Field Soils
Authors: Høgh Jensen K. , Refsgaard J. C. 
Published: May 2018

A numerical analysis of solute transport in two spatially heterogeneous fields is carried out assuming that the fields are composed of ensembles of one-dimensional non-interacting soil columns, each column representing a possible soil profile in statistical terms. The basis for the analysis is the flow simulation described in Part II (Jensen and Refsgaard, this issue), which serves as input to a transport model based on the convection-dispersion equation.
The simulations of the average and variation in solute concentration in planes perpendicular to the flow direction are compared to measurements obtained from tracer experiments carried out at the two fields. Due to the limited amount of measurement data, it is difficult to draw conclusive evidence of the simulations, but reliable simulations are obtained of the mean behaviour within the two fields.
The concept of equivalent soil properties is also tested for the transport problem in heterogeneous soils. Based on effective parameters for the retention and hydraulic conductivity functions it is possible to predict the mean transport in the two experimental fields.
Non-Parametric Statistics on Extreme Rainfall
Authors: Arnbjerg-Nielsen K. , Harremoës P. , Spliid H. 
Published: May 2018

This article focuses on rain as input data to problems related to urban storm drainage. The rain data originate from a monitoring program consisting of 56 gauges in Denmark. The gauges have observation periods ranging from 2 to 14 years. The gauges sample rain in a quantity of 0.2 mm with a resolution in time of 1 minute.
Two variables have been investigated: peak intensity and depth. Design values for return periods in the range from 0.1 to 2 years have been estimated for each gauge separately by means of the bootstrap resampling method. The estimation includes expected value, standard deviation and confidence intervals of the design value.
For large return periods the uncertainty of the estimates prevents a distinction by gauge between different statistical populations. However, for small return periods a test shows significant variation between gauges, i.e. the uncertainty of the estimates may not be assumed to be due to sampling variability only.
Photogrammetric Analysis of a Slush Torrent in the Kärkevagge, Northern Sweden
Authors: Scherer Dieter , Groebke Lukas , Parlow Eberhard 
Published: May 2018

Slushflows have been investigated in various regions of the Earth for more than forty years. Most of the observed events occurred in mountainous drainage basins at high latitudes, so relatively few observations and measurements are presented in the scientific literature. This particularly holds for slush torrents which are major slushflow events reaching supercritical flow velocities. Thus, information on dynamical features of slush torrents are rather limited, and most results are based on qualitative observations.
On June 3,1995, during a field campaign in the Kärkevagge, a drainage basin in Swedish Lapland, a slush torrent could be observed and documented by a time series of photographs and by video recordings. Quantitative results from a photogrammetric analysis of the photographs show that the first wave front of that slush torrent reached peak velocities of more than 40 ms−1. A second wave front was able to reach even higher velocities due to the fact that the first wave had almost completely removed all snow from the transport path. Consequently, the viscosity of the flow was significantly reduced. To the author's best knowledge, these results are the first quantitative measurements of a slush torrent during its movement.
Estimating Soil Moisture in Small Watersheds, Using a Water Balance Approach
Authors: Rim Chang-Soo , Gay L.W. 
Published: May 2018

Soil moisture content was estimated daily by a energy balance and water budget (EBWB) analysis of two small subwatersheds in the Walnut Gulch Experimental Watershed near Tombstone, Arizona. One watershed was 8.1 ha and covered with grass, and the other was 48.6 ha and covered with shrubs. The four-week experiment took place in July and August, during the summer rainy season that dominates the precipitation pattern of southern Arizona.
Mean daily soil moisture (SM, mm) was estimated by a water balance at each watershed, using precipitation (P), runoff (RO) and evapotranspiration (ET). Daily ET estimates were derived from an energy balance on each watershed, using measured net radiation (Qn), soil heat flux (Qg) and sensible heat flux (Qh) to solve for latent energy (QLE, and hence ET) as a residual term. Next, independent estimates of watershed SM were obtained from Time Domain Reflectometry (TDR). The results of simple correlation analyses between the methods showed that the simple correlation coefficients for Lucky Hills and Kendall are 0.764 and 0.791 respectively. The agreement of the two sets of soil moisture measurements confirms that simple water and energy balance measurements can yield appropriate estimates of soil moisture in small watersheds.
International waters: identifying basins at risk
Authors: Wolf Aaron T. , Yoffe Shira B. , Giordano Mark 
Published: May 2018

Despite the growing literature on water and conflict in international river basins, little empirical work has been done to bolster common conclusions which are so widely reported. In order to address this gap, we set out to assess all reported events of either conflict or cooperation between nations over water resources during the last 50 years and to use these events to inform the identification of basins at greatest risk of political stress in the near future (5-10 years). The study is divided into three components:Compilation and assessment of relevant biophysical, socio-economic and geopolitical data in a global Geographic Information System (GIS), and use of these factors to determine history-based indicators for future tensions along international waterways.Using these indicators, identification of basins at risk for the coming decade.Identification and assessment of the potential for mitigating factors and new technologies resulting in a future different than that predicted by history-based indicators.
In general, we find that most of the parameters regularly identified as indicators of water conflict are actually only weakly linked to disputes, but that institutional capacity within a basin, whether defined as water management bodies or treaties, or generally positive international relations are as important, if not more so, than the physical aspects of a system. It turns out then that very rapid changes, either on the institutional side or in the physical system, which outpace the institutional capacity to absorb that change, are at the root of most water conflict, as reflected in two sets of indicators: 1) “internationalized” basins, i.e. basins which include the management structures of newly independent states, and 2) basins which include unilateral development projects and the absence of cooperative regimes. By taking our parameters of rapid change as indicators-internationalized basins and major planned projects in hostile and/or institution-less basins-we are able to identify the basins with settings which suggest the potential for political stresses in the coming five to ten years. These basins include: the Ganges-Brahmaputra, Han, Incomati, Kunene, Kura-Araks, Lake Chad, La Plata, Lempa, Limpopo, Mekong, Ob (Ertis), Okavango, Orange, Salween, Senegal, Tumen and Zambezi.
We then identify “red flags,” or markers related to these indicators, which might be monitored in the future. Finally, recognizing that history-based indicators may lose validity over time in a rapidly changing world, we ask, “what about the future, which may look nothing like the past,” and focus on four topics: new technologies for negotiation and management; globalization, privatization and the WTO; the geopolitics of desalination; and the changing sources of water and the changing nature of conflict.