bluuebunny/crossref_metadata_2025_split huggingface dataset:
WEATHERING AND HYDROGEOLOGY OF THE BRUMUNDDAL SANDSTONE, SOUTHERN NORWAY
Authors: ENGLUND J. O. , JØRGENSEN P. 
Published: May 2018

During the last decades several wells giving yields up to 100,000 1/h have been drilled in the reddish Brumunddal Sandstone, which covers an area of approximately 10 km2 near lake Mjøsa, Southern Norway.
Most of these wells have yields below 10,000 1/h, and those with higher yields are situated along prominent fracture zones. Textural data strongly support the assumption of an eolian origin for this sandstone, but water-deposited sediments are found within the formation.
Most of the grains are coated with a hematite pigment, which was probably epigenetically formed. Post-sedimentary but preglacial weathering processes have transformed plagioclase to montmorillonite. This has changed the porosity as well as the permeability and increased the cationic exchange capacity. A transformation of plagioclase is in agreement with the groundwater composition.
THE DEVELOPMENT OF A SNOW ROUTINE FOR THE HBV-2 MODEL
Authors: BERGSTRÖM STEN 
Published: May 2018

The development of a snow routine for the HBV-2 rainfall-runoff model is described. Experiences from field investigation that have contributed to the work are briefly discussed.
In the snow routine, snow accumulation and snowmelt are simulated using daily totals of precipitation and mean daily temperatures. The application of the model to a 2178 km2 forested basin in central Sweden is shown. A critical study of the interaction and effects of the parameters is carried out.
NORTHERN RESEARCH BASINS
Authors: FORSMAN ARNE 
Published: May 2018

Following recommendations of a preliminary meeting in Calgary, Canada, in February 1974 between representatives of the IHD Committees of Canada, USA and Sweden, and discussions at the Unesco House in Paris, France, in September 1974 between representatives of the IHD Committees of Canada, USA, Finland, Norway and Sweden, a Workshop Symposium on Northern Research Basins - Objectives and Measurements was organized at Edefors, Sweden, 7–11 April 1975.
The meeting was convened jointly by the Swedish IHD Committee and the Swedish Meteorological and Hydrological Institute and organized by the Swedish Meteorological and Hydrological Institute. It was held close to the Lapptrasket Research Basin.
Participation in the workshop was arranged through the National IHD Committees of the participating countries: Canada, USA, Norway, Finland, the Soviet Union and Sweden.
Nitrogen Movement and Leaching in Soil
Authors: Jensen H. E. 
Published: May 2018

Movement and leaching of residual nitrogen in soil has been studied in some details in a lysimeter experiment. Profile measurements of soil water and of nitrogen concentration in addition to measurements of amount and composition of the drainage water were carried out.
The leaching process could be described by an equation of Day. For a flow rate of approximately 1 cm/day, a dispersion coefficient of 11.5 cm2/day was obtained independent of the concentration level. Using this value, the equation satisfactorily predicted concentration of nitrogen and leached amount of nitrogen in the drainage water. The equation, although the assumptions inherent in the theory are not completely fulfilled, may therefore be used for predictive purposes under field conditions.
An excess of precipitation, approximately equal to field capacity, is predicted necessary for leaching 50 per cent of an amount of dissolved nitrogen initially localized at the surface of the soil. Consequently, under many soil/climate conditions, the composition of drainage water is influenced by agricultural practices from previous years, which makes difficult interpretation of the results. This has been illustrated by relating some available data on drainage water quality from field experiments to the concentration of nitrogen in the soil water, as predicted by the theory.
Reservoir Mechanism
Authors: Eliasson Jonas , Kjaran Snorri Pall 
Published: May 2018

The physical problem dealt with in this article is the unsteady groundwater flow in an isotropic, nonhomogenous aquifer of limited horizontal extent and arbitrary boundary shape.
The unsteady ground-water level is described by a differential equation which is solved by the Galerkin finite element method, combined with orthogonal eigenfunctions. Unlike many numerical procedures the physical properties of the aquifer are not lost. Boundary conditions are provided by nature in the form of watertight rocks, rivers, lakes or any kind of constant water level in hydraulic contact with the aquifer, or given boundary inflow or outflow.
Multivariate Distributions in Hydrology and River Regulation
Authors: Kartvelishvili N.A. , Gottschalk L.T. 
Published: May 2018

It is assumed that the river runoff process can be approximated by a Markov process. The process is thus described by M distribution functions:
Fn (qt, t ; qt-1; t-1;…;qt-n, t-n), t ≡ 1, 2, …, M where M is the number of time intervals within the year, n - the order of the Markov process and qt, in general, is a vector representing runoff at several sites in a river or neighbouring rivers.
Fundamental hypothesis of relations between multivariate distributions and corresponding marginal distributions is given.
A finite difference scheme for multisite and multilag generation of river runoff is derived. The derivation is based on the multivariate normal distribution.
Different methods for determination of the order of the finite difference scheme are discussed as well as the influence of model order and method of parameter estimation on properties of the model.
Drawdowns at the Free Water Table During Pumping Tests in Artesian and Semiartesian Aquifers
Authors: Kærgaard Henrik 
Published: May 2018

In an earlier paper I have shown an example of how long term drawdowns can be used for the computation of long term storage in artesian and semiartesian areas. In most cases the long term storage is more or less equivalent to the specific yield at the water table; the storage mechanisms of consolidation playing a minor role in long term situations. The specific yield in artesian areas is a very important parameter in the prediction of long term effects of ground water withdrawal. Especially the stream depletion will often mainly be governed by draw-downs in upper nonpumped aquifers near the water table, and these drawdowns depend to a great extent on the specific yield at the water table.
A determination of long term storage will often necessitate long term draw-down data, however, under certain circumstances a determination can be made on the basis of a pumping test of limited duration (3-5 weeks) provided drawdown observations at the water table can be made. In this paper some formulas dealing with water table drawdowns in different geohydrologic systems are reviewed, and two cases in which these formulas have been used in practice are presented.
On the Heat Exchange Between Rivers and Atmosphere
Authors: Stang Ole 
Published: May 2018

In order to be able to predict water temperatures in rivers which are to be harnessed for hydro power, it is essential to take into account the heat exchange with the atmosphere. It is often sufficient to predict average temperatures and temperature changes for periods of some days. A simple model for the heat exchange between flowing water and atmosphere has been developed for this purpose. The model offers a semi-empirical relationship between air temperature and water temperature.
In this paper the model is applied to the Orkla river in Central Norway, and it is demonstrated how analyses of diurnal variations of water and air temperatures make it possible to predict the downstream decay of temperature changes originating from man-made releases. As a result an average heat exchange coefficient is calculated for Orkla for the summer of 1980. This calculation indicates that the cooling/heating rate in the flowing water in Orkla is considerably greater than the one for lakes under the same meteorological conditions.
A Modified Sediment Transport Model for Natural Streams
Authors: Thomsen Thorkild 
Published: May 2018

In an earlier investigation of the behaviour of tracer particles for determination of bed load transport in an alluvial stream (Thomsen 1980), specific records were taken of the particle velocities in the upper bed layer. These data aroused the interest for more detailed investigations.
The result of the measured surface particle velocities with radioactive tracers, performed in five locatities with different hydraulic conditions in natural alluvial rivers, has been used for determination of the relation UG/Uf'vs. √θ'/θ0.
The obtained results have been inserted in the parameters of Engelund and Fredsøe's sediment transport model (1976) and compared with experimental data (Guy et al. 1966).
Some reservations and methods for possible improvements of the sediment transport model are finally discussed.
A Distributed Groundwater/Surface Water Model for the Suså-Catchment
Authors: Refsgaard Jens Chr , Hansen Eggert 
Published: May 2018

A distributed physically based model of the entire land phase of the hydrological cycle has been developed for the Suså-area, covering about 1,000 km2 of Zealand, Denmark. The model is described in part I of the paper, also presented in this volume. The model's ability to simulate the streamflow depletion caused by a groundwater abstraction from a confined aquifer, overlaid by Quaternary drift deposits, has been tested on historical streamflow data from the catchment of Køge Å. This catchment has been heavily influenced by a major groundwater abstraction started in 1964.
The physical mechanisms of streamflow depletion are discussed, and the effects of a groundwater abstraction on the recharge to the confined aquifer and on the streamflow are illustrated. General conclusions regarding streamflow depletion due to groundwater abstraction are made.
Representativeness of Chemical Analysis of Groundwater
Authors: Aastrup Mats , Axelsson Carl-Lennart 
Published: May 2018

This paper raises the question of the representativeness of a single chemical analysis of groundwater. This is undertaken with the knowledge of the variations in chemical constituents obtained in the groundwater chemistry programme of the Groundwater network of SGU.
The variations in time and space are described for an area of 30 km2. The main geological feature of the area is a glaciofluvial esker. The esker is surrounded by littoral sand and till. The measurements show that the pH varies in a similar way in the three types of aquifers, but the variations in alkalinity, calcium content and conductivity are much greater within the till aquifer than in the aquifers consisting of glaciofluvial and littoral material.
An example is also given of the significance of depth and hydrogeological location within a small till aquifer on the level of concentration of some chemical substances in groundwater.
Simulation of Water Resources Development Projects in the Nam Kam Basin, Thailand
Authors: Nielsen M. Dyhr , Storm Børge 
Published: May 2018

The Nam Kam basin is located in north east Thailand, discharging into the Mekong river. At present, a hydropower project has been constructed in the basin, and Nong Han, a natural lake, is regulated for fish-production purposes. In addition, four potential reservoir sites for irrigation projects have been identified.
The water availability resulting from various combinations of project developments has been analyzed by a simulation model.
Rainfall-runoff-models were calibrated on typical subcatchments. Based on 30 years of rainfall data, a long time series of natural inflow to the various project sites was simulated. Water level variations in the reservoirs were simulated based on inflows, reservoir losses and releases. A plant-soilwater model was developed for simulation of irrigation requirements of rice paddy and upland crops.
For various cropping alternatives, the total irrigation water availability for the basin was determined under the assumption that shortages may occur in one out of five years. The simulations formed the basis for a water master plan of the basin.
For the Lower Nam Kam Project, a detailed simulation of the operation of a 14,000 ha pump irrigation project was carried out. Based on 30 years of simulated data for inflow and irrigation requirements, pumping needs and power consumption of 4 irrigation pump stations and a feeder pump station at Mekong was determined. The results formed part of the basis for the feasibility study of the project.
Oxygen Depletion in the Kattegat
Authors: Jacobsen T.S. , Ottesen Hansen N.-E. 
Published: May 2018

A mathematical model driven by meteorological forcing and sea level differences has been established in order to describe the water exchange and vertical mixing in the Kattegat and Samsø Belt.
The model has been run with a time-step of 1 day for the period April - October from 1961 to 1981. The mixing has been represented by equations from the theory of turbulence with the normally used coefficients, i.e. no calibration has been necessary. Results from earlier investigations have been used to describe the flows in the Belts and the Sound.
The vertical exchange between the upper, brackish and the lower, saline water is strongly dependent on the meteorology. A small meteorological activity results in small exchange flows which implies that the oxygen supply to the lower layer becomes smaller and unfavourable biological conditions may occur. A simple calculation has been carried out on the assumption that the chemical and biological oxygen demand is a first order process with a time scale for the oxygen decay, which is halfed for each 10° increase of temperature. Thus the model describes the effect of the meteorological activity on the oxygen concentration, all other parameters kept constant.
Spring Characteristics and Hydrological Models of Catchments
Authors: Englund Jens-Olaf 
Published: May 2018

The Åstdalen catchment (373 km2) represents largely a natural ecosystem, typical for the higher central and southern parts of the Scandinavian Peninsula. It is underlain by fractured sedimentary rocks with a thin cover of unconsolidated Quaternary deposits.
The runoff process in Åstdalen is mainly determined by: Large accumulation of precipitation as snow, large areas covered by peatlands, and a high waterstorage capacity in the bedrocks. Groundwater discharge occurs in river beds, in springs and as flow towards the soil surface, especially toward peatland areas.
The discharges of the main river Åsta and of investigated springs rise rapidly following snowmelt and rainstorms during the two water-years of study, 1 October 1980 to 30 September 1982. This shows that the catchment has a high infiltration capacity, and that water moves rapidly downslope in the saturated zone, following macropores in soils, peatlands and bedrock fractures. Groundwater, especially shallow groundwater, plays an important role of streamflow peak generation, even during snowmelt. About 60-70 % of the river discharges during the melting periods in 1981 and 1982 were baseflow.
There is a net gain of protons, ammonium, potassium, nitrate and chloride to the catchment from the atmosphere during the year, and a net loss of calcium, magnesium sodium and sulfate. Constituents showing a net loss have an internal geologic and/or organic source in addition to the atmosphere.
The concentration of most substances in river Åsta and in the investigated springs are lowered during peak flows. The concentration of protons is on the other hand typically increased during snowmelt. This indicates that fresh rain and/or snowmelt water dominates such flow periods and not older prestorm water.
About 56 % of the protons needed to supply the weathering-derived ions to river Åsta come from precipitation.
Mixing Effects of Carbonate Dissolving Waters on Chemical and 13C/12C Compositions
Authors: Staniaszek P. , Halas S. 
Published: May 2018

Seasonal variations in chemistry and 13C/12C ratios of total inorganic carbon of carbonate dissolving waters are considered in the frame-work of a simplified approach dealing explicitly with major ionic species. The unidirectional evolution models of Deines et al. (1974) are supplemented by taking mixing effects into consideration (Wigley and Plummer 1976). These effects, caused mainly by the redistribution of carbon-bearing species in the mixture, are to a great extent nonlinear and unsymmetric with respect to the fraction of the second solution in a binary mixture. The theoretical considerations are supported by observations of many samples taken during a period from January to May 1977 in SW Lublin Upland.
The parameters PCO2 and δ13C of a reservoir lose their primary meaning in the case of mixing of waters but investigation of their changes may help in studying some conditions in the soil. During the period of observation (except March) the estimated values of PCO2 of a reservoir tended to he in a narrow range of values from 10−1.3 to 10−1.4 atm. In March those values were higher due to the large inflow of CO2-rich waters into the aquifer. The estimated δ13C values of a reservoir CO2 spread from –17 to –27 permil during January to March. In April and May those values focused in a narrow range from –22 to –26 permil. This tendency indicates that waters inflowing in March and April transported isotopically lighter CO2.
Both HCO3− content and δ13C of total carbon versus pH allowed to search inflows of infiltrating water into particular areas of the aquifer. It has been shown that δ13C investigations are necessary to notice the admixing of waters in certain cases.
On the Correction of Liquid Precipitation
Authors: Allerup P. , Madsen H. 
Published: May 2018

The paper discusses a bi-linear statistical model for correcting aerodynamic errors, earlier presented by Allerup and Madsen, 1980. Further data from Finland, USA and Australia testing the model will be presented. A simplification of the bi-linear model in order to cover different gauge types and varying measuring levels will be demonstrated. The simplification will extend the applicability of the correction model when implemented into automatic correction systems.
The paper will discuss the problems of fit by the simplified model and attention will be given to physical interpretation of the mathematical structure in the model.
Besides aerodynamic errors, wetting losses influence the correction values. It will be demonstrated how these effects cause too large corrections for small amounts of precipitation and too small corrections for large amounts.
Modelling of Unsaturated Flow in Heterogeneous Soils
Authors: Høgh Jensen K. , Butts M. B. 
Published: May 2018

Modelling of soil moisture conditions in spatially variable fields is treated using stochastic methods. Spatial variability of moisture content in a vegetation covered field is partly caused by field variability in soil physical parameters. In the present study a physically based model is coupled with a statistical description of retention properties and saturated hydraulic conductivity respectively to simulate moisture conditions in heterogeneous soils.
Results are compared with measurements obtained from two 0.5 ha field sites.
Simulations based on the variation in retention properties are shown to account for much of the observed variation in soil moisture conditions with some deficiencies evident close to the soil surface. Variations in saturated hydraulic conductivity alone give an incomplete description of observed variability in soil moisture conditions.
Operational Spring Time Forecasting Difficulties and Improvements
Authors: Vehviläinen Bertel 
Published: May 2018

A modified version of HBV-3 model has been used since 1981 for operational spring-time forecasting in Finland. This model is ready now for eleven river basins ranging from 500 to 30,000 km2. From the experience with these models in forecasting we have learned to know the common difficulties and errors in real-time forecasting and some methods to improve forecasting results.
The main difficulties with forecasting during spring time in Finnish conditions have been: unstable parameters in snowmelt models, heavy unforecasted rainfall, evaluation of areal water equivalent of snow and ice-dams in rivers.
The methods to overcome these difficulties are: the development of more physically based snowmelt models, new methods to determine initial value of areal water equivalent of snow, the use of statistical error models with hydrological model, the automatization of observation and transport of hydrological and meteorological data and the improvement of areal precipitation calculations.
Estimation of Catchment Rainfall Uncertainty and its Influence on Runoff Prediction
Authors: Storm B. , Jensen K. Høgh , Refsgaard J. C. 
Published: May 2018

Interpolation of spatially varying point precipitation depths introduces uncertainties in the estimated mean areal precipitation (MAP). This paper describes a geostatistical approach – the Kriging method – to calculate the daily MAP on real-time basis. The procedure provides a linear unbiased estimate with minimum estimation variance. The structural analysis of the random precipitation field is automatized by relating the time-varying semivariogram model to the sample variance. This is illustrated on data from a Danish IHD catchment.
The conceptual rainfall-runoff model NAM incorporated into a Kalman-filter algortithm is applied to investigate the effects of uncertainties in MAP on the runoff predictions. Measurement and processing errors are not included in the investigation.
Assessing the Effect of Longitudinal Density Gradient on Estuarine Hydrodynamics
Authors: Aiyesimoju Kolawole O. 
Published: May 2018

If the impact of longitudinal density gradient on the hydrodynamics of estuaries is negligible, then in water quality simulations, the hydrodynamics can be decoupled from the mass transport which would lead to substantial savings in computational time and storage requirements. It is thus important to be able to assess this impact beforehand.
The impact of longitudinal density gradients is evaluated analytically in the context of a one-dimensional wide rectangular channel taking into account the influence of bed slope, bottom friction, type of boundary condition and transient effects. The analysis predicts actual errors that would arise in numerical computations from near exactly in the best cases to within a factor of 6 in the worst cases. It should thus be useful for at least an order of magnitude prediction of the errors that would arise from the neglect of the effect of longitudinal density gradient on estuarine hydrodynamics.