bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response of Soil Moisture Change to Hydrological Processes in a Continuous Permafrost Environment
Authors: Woo Ming-ko , Marsh Philip 
Published: May 2018

The moisture content of the active layer at three sites in a continuous permafrost area was measured using a twin-probe gamma density meter. The moisture storage status at these sites were related to various hydrological processes. Moisture was gained by meltwater and rainfall infiltration, but lost to evaporation in summer. Lateral inflow maintained a thick saturated zone at the fen (wetland) site. At the gravel site, there was a net moisture loss due to evaporation and lateral outflow.
Moisture changes in the active layer during the summer were examined in terms of the water balance at the three sites. This established quantitative relationships between the moisture regime and the major hydrological processes in the permafrost environment.
Modeling the Effects of Rainfall Variability on Groundwater Recharge in Semi-Arid Tanzania
Authors: Sandström Klas 
Published: May 2018

A conceptual model of the effects of rainfall variability on groundwater recharge was developed and applied to a small forested catchment in semi-arid Tanzania. The model simulated dual-domain recharge through the soil matrix and macropores, and was based on daily values of rainfall and potential evapotranspiration. Three different land-cover conditions (forested-nondegraded, deforested-nondegraded, and deforested-degraded) were included in the study in order to simulate the large-scale deforestation and land degradation process now occurring in Tanzania. In addition, the alternative land covers were also considered in combination with three different rainfall regimes.
The results indicate the importance of macropore flow, particularly during dry years. The lack of macropores under deforested-degraded conditions reduces the simulated groundwater recharge to such an extent that it is less than under forested conditions. Simulating a climate change scenario shows that a small change in rainfall (-15%) can cause a large change in recharge (-45%).
Preliminary Considerations for Runoff Modelling in GCMS
Authors: Verseghy Diana 
Published: May 2018

Modelling of runoff in GCMs is a two-stage process: first, a residual water amount resulting from precipitation, evapotranspiration, snowmelt, infiltration and soil moisture movement at each time step must be generated for each grid cell; then a runoff routing model must be applied to this water excess to produce streamflow. Incorporation of the latter into GCMs is as yet in the most initial stages, and will not be reliably achieved for some years to come. However, before this can be accomplished, the water excess that is to be routed must be generated in a physically realistic fashion.
Two land-surface models of widely varying complexity are presently available as options in the Canadian GCM (developed at Atmospheric Environment Service, Canada). The old scheme is based on a bucket approach for soil moisture and on the force-restore method for soil temperature; a more recently developed scheme (“CLASS” – Canadian Land Surface Scheme) incorporates physical modelling of the heat and moisture budgets of three soil layers, the snow cover and the vegetation canopy. Based on comparisons of year-long runs of both models, it is postulated that reliable modelling of the surface water excess cannot be achieved using a “bucket” model. It is also shown that sub-grid scale variability of the precipitation rate must be taken into account, and that the land surface model must allow for surface water retention between timesteps.
Areal Precipitation and Temperature in the Swedish Mountains
Authors: Johansson Barbro 
Published: May 2018

This paper presents an evaluation of three different methods for estimation of areal precipitation and temperature, with special emphasis on their applicability for runoff modelling in the Swedish mountains. All three methods estimate the areal values as a weighted mean of the observations at nearby meteorological stations. The weights are determined by:
1) a manual subjective selection of the most representative stations
3) inverse square distance weighting
4) optimal interpolation
The methods were tested in an area with complex topography and precipitation gradients. The evaluation included comparison of areal estimates, verification against point observations and the water balance equation, and sensitivity analyses with respect to method parameters and network changes.
The evaluation showed that for simple runoff modelling the subjective and optimal interpolation methods performed equally well, and considerably better than inverse-distance weighting. The evaluation also showed that none of the methods correctly described the spatial variation in precipitation and temperature in the investigated region. They are thus not directly applicable for non-routine modelling applications where the estimation of runoff is not the sole objective. All methods proved to be sensitive to the selection of parameter values, which pointed to possible improvements of the estimates. The optimal interpolation method seemed to be the least sensitive to changes in the meteorological network.
Snow Distribution at a High Arctic Site at Svalbard
Authors: Bruland Oddbjørn , Sand Knut , Killingtveit Ånund 
Published: May 2018

In the Arctic regions snow cover has a major influence on the environment both in a hydrological and ecological context. Due to strong winds and open terrain the snow is heavily redistributed and the snow depth is quite variable. This has a significant influence on the duration of the melting season, on the possibilities of greenhouse gas exchange, the plant growing season and therefore the arctic terrestrial fauna. The aim of this study is to describe the snow depth variability by detailed measurement of snow distribution in a 3 km2 site near to Ny-Ålesund at 79° north of Svalbard and to link this to topography and climate at the location. The measurements were carried out in a grid of 100 m by 100 m cells using the SIR-2 Georadar from Geophysical Survey System Inc. (GSSI).
Differential GPS was used to create a detailed Digital Elevation Model (DEM) and the snow depth data were correlated to topographic data. The average snowdepth in the area was about 70 cm with a standard deviation of 40 cm. Statistical distribution and spatial correlation for the snow depths were found. The method was found acceptable for snow distribution mapping. The main observation was the major accumulation in the west facing slopes due to easterly winds that are dominant in this area.
Interannual and Seasonal Temperature and Salinity Variations in the Gulf of Riga and Corresponding Saline Water Inflow From the Baltic Proper
Authors: Raudsepp Urmas 
Published: May 2018

Salinity and temperature data from the Gulf of Riga, a semi-enclosed sub-basin of the Baltic Sea, were analyzed with a focus on interannual and seasonal variability. The data were compiled from measurements taken from 1973 to 1995, a period which includes the stagnation period in the Baltic Sea. Interannual and seasonal variations in the net inflow of saline water from the Baltic Proper were estimated from volume and salt conservation equations for the period 1973-90.
The basic decreasing trend, superimposed interannual variations in salinity, and interannual and seasonal temperature variations in the Gulf of Riga coincided with corresponding changes above the halocline in the Baltic Proper. Seasonal salinity variations were notable in the Gulf of Riga as compared to the Baltic Proper, where variations were negligible. Estimated annual mean inflow varied between 2,000 and 5,000 m3/s (average 3,200 m3/s), with a notable increasing trend. A simultaneous increasing trend was extracted from annual mean river flow data. Short-term fluctuations (over 4-6 years) of annual mean inflow ran opposite to the fluctuations of the magnitude of river flow. The average salinity in the Gulf of Riga increased during strong inflow and weak river flow and decreased when inflow was weak and river flow was strong. Variations in the inflow of water salinity had a minor effect on salinity variations in the Gulf of Riga. Seasonal inflow was strongest in spring and autumn and weak in winter.
Comparison of Modeled Water Input and Measured Discharge Prior to a Release Event: Unteraargletscher, Bernese Alps, Switzerland
Authors: Schuler Thomas , Fischer Urs H. , Sterr Regina , Hock Regine , Gudmundsson G. Hilmar 
Published: May 2018

A distributed temperature index melt model including potential clear-sky solar radiation was applied to Unteraargletscher, Bernese Alps, Switzerland, to quantify water input to the glacial hydrological system during the ablation season 1999. Model parameters were determined by calibrating calculated melt with ablation measurements. Discharge was measured in the proglacial stream for 18 days until the station was destroyed by an outburst flood.
Comparison of modeled melt and measured discharge reveals that routing processes of water through the glacier vary with time as the water is transferred through a dynamic drainage system. Furthermore, an imbalance of water input and output suggests that water was stored in or beneath the glacier during this period. The culminating outburst flood presumably released this en– or subglacially stored water and may be related to a change in the configuration of the glacial drainage system as inferred from measurements of subglacial water pressure.
The Correlation Between Extreme Wind and Flood Events in Unregulated River Basins
Authors: Harstveit Knut , Jenssen Lars 
Published: May 2018

The aim of this investigation is to improve the method for calculating design wind speed used for wave run up at water reservoirs. It is focused on the relation between extreme flood and wind events, and between wind speed and duration.
Water flow data from fourteen Norwegian river basins and wind data from neighbouring airfields are correlated. Some positive correlation is found for areas situated at the coastal side of the mountains where a further analysis is carried out. Extreme value analysis of the wind and flood series provides estimates of T-year events for each of the two variables. The best-fitted equation linking the square of the maximum 10-minute wind speeds to the daily mean water flow is established. It is observed that the expected wind speed during the 1000-year daily flood event has approximately one year return period. The risk for higher wind speed is high, so the effect of adding 1 and 1.65 standard deviations of the maximum wind speed is assessed, increasing the expected return period to 5 and 20 years respectively.
Continuous records of 10-minute wind speed are used to establish transfer coefficients from the extreme 10-minute value to durations of 20 minutes to 6 hours.
A comparison between the ERA40 and the SMHI gridded meteorological databases as applied to Baltic Sea modelling
Authors: Omstedt A. , Chen Y. , Wesslander K. 
Published: May 2018

Two gridded meteorological data sets for the Baltic Sea region, both having 1°×1° horizontal resolution, were compared and analysed for use in Baltic Sea modelling. The SMHI 1°×1° data set covers surface parameters with a three-hour time resolution over the 1970–2004 period. The ERA40 data cover analysed and modelled parameters for several atmospheric layers with a six-hour time resolution over the 1957–2002 period. Meteorological variables considered in this analysis were air temperature, wind speed, total cloud cover, relative humidity and precipitation. In considering Baltic Sea modelling, we examined maximum ice extent, water temperature, salinity and net precipitation calculations.
The two data sets are largely similar and can both be used in Baltic Sea modelling. However, their horizontal resolution is too coarse for resolving marine conditions over the Baltic Sea. This implies, for example, that the ERA40 original surface winds are too low for some Baltic Sea regions. The ERA40 precipitation values are also too low compared with those of the SMHI and other available data.
Institutional arrangements for integrated river basin management
Authors: Jaspers Frank G. W. 
Published: May 2018

This paper considers the institutional arrangements that are needed and that being developed to enable communities to depart from sectoral and isolated water management in order to reach a higher level of integration. Key aspects are described that should be properly handled to manage river basins as a whole and in an integrated way.
The justification for various countries to opt for systems of integrated river basin management is explored. Triggers for change are identified: the need for integrated water management on hydrological boundaries; the added value of functional decentralisation enabling decision making at the lowest appropriate level; stakeholder participation in decision making and water resources planning; and cost recovery and water pricing.
Ongoing developments in processes of change are identified and described. A comparative assessment is carried out between the situation in Zimbabwe, South Africa, Tanzania, Turkey, Indonesia, France and The Netherlands. A common denominator of institutional arrangements is determined, from which developing countries in particular could benefit with regard to the introduction and establishment of systems of integrated river basin management. Sample competencies for effective functioning of river basin and sub-basin organisations are identified and described. Platforms of stakeholders with clear rules for representation and for participation in decision making in water resources planning are identified as crucial tools and described. In order to apply effective water pricing and to charge for pollution, a comprehensive system of water rights and discharge permits is considered necessary. The capacity to implement these necessary institutional arrangements is very variable, especially in developing countries, and hence the stage of implementation may differ substantially. Further, it is very important to have initial access to funds to kick-start the process of implementation. It has been found that systems of cost recovery can only be successfully introduced when acceptable service levels are established and when an enabling institutional environment is in place. Investments are needed and not all countries can afford that.
Above all, a major requirement for implementation of any institutional development is the presence of sufficient human and institutional capacity at the right time and at the right place.
Remaining challenges for bi-national agreements on shared water: The Umbeluzi case
Authors: Juizo Dinis , Lidén Rikard , Vaz Álvaro Carmo 
Published: May 2018

In Southern Africa, joint management of international waters is necessary for regional development and stability. The 1997 UN international convention on “watercourses for Non-navigational uses” and the 2000 revised SADC (South African Development Community) “Protocol on Shared Watercourses” form part of the platform towards minimising tension over utilisation of water resources in the region. Mozambique shares nine of 15 international rivers in SADC, hence its continued efforts towards reaching agreements with the riparian countries. However, effective implementation of these agreements remains a challenge.
This study focuses on the implementation of future agreements in Umbeluzi River which has only two co-riparian sovereign states – Mozambique and Swaziland. In this case, it was found that several factors affect the effective implementation of the desired equitable sharing principle. The most prominent are hydrological data uncertainty, lack of adequate modelling tools and insufficient institutional capacity. Factors like large climatic variability in the region further worsen the situation. The overall implementation of agreements is also dependent on stakeholders' willingness to cooperate, which in turn is linked to their sense of fairness on decisions imposed by officials. However, correct regulation and enforcement can narrow the gap between technical ingenuity and the actual system behaviour.
Occurrence and removal of Giardia and Cryptosporidium at the Goreangab reclamation plant
Authors: Menge J.G. , Haarhoff J. , König E. , Mertens R. , van der Merwe B. 
Published: May 2018

This paper deals with the occurrence of Giardia and Cryptosporidium in the water sources available for the Goreangab Reclamation Plant (GRP) and the subsequent removal during treatment at the reclamation plant. Giardia is detected more often than Cryptosporidium. 60% of the time it is detected in the samples from the dam and in 55% of the samples from the maturation pond effluent.
During the investigation, Giardia was detected in the final water 5% of the time and Cryptosporidium 2% of the time. The maximum Giardia cysts detected in a sample was 30, the 99% percentile was 20 and the 97% percentile 10 cysts. A maximum of 20 Cryptosporidium oocysts was detected in a sample. The 99% percentile counted 6.2 oocysts and the 97% percentile 0 oocysts.
From the data presented it is clear that the polluted dam water has the same risk level of Giardia and Cryptosporidium pollution as treated wastewater effluent. This emphasises the fact that the sources should be monitored continuously for these parasites. The sporadic high counts of Giardia and Cryptosporidium in the raw water sources indicate that a multiple-barrier approach must be followed to ensure the safe operation of even conventional treatment plants using polluted source water.
No correlation could be found between cyst and oocyst removal and other water quality parameters.
The advocating of a final water turbidity of 0.1 NTU and the use of particle counters can only be supported by these findings, as it is possible to achieve a turbidity of less than 0.1 NTU at the sand filter outlet, even in a developing country like Namibia. The challenge lies with the maintenance of equipment and vigilance of the operators.
Pre-treatment with dissolved air flotation considering an integrated process design
Authors: Dahlquist J. , Kulesza M. 
Published: May 2018

The raw water from Lake Zegrzynski is difficult to treat and requires a high chemical dosing rate of coagulant for the reduction of organic matter in order to comply with EU standards. The high degree of reduction calls for an efficient coagulant, but also an optimal chemistry such as correct dosing amount and an optimal flocculation-pH. The paper describes different removal efficiencies of organic matter, particularly with respect to pH in flocculation.
During the warm season, the raw water can also suffer from large amounts of plankton that are difficult to remove to a satisfactory degree. In a two-step chemical treatment concept, with Dissolved Air Flotation (DAF) and the pulsator process, the plankton content in the final outlet water is reduced to very low levels. It follows that eventual peaks of plankton in the raw water cannot be detected in the final outlet water.
Ozone is added for removal of taste and odour originating from the presence of plankton. In the pre-treatment step prior to the ozonation, a great deal of the organic matter is removed, which reduces the necessary ozone dosage.
The Municipal Water Company of Warsaw City has decided to consider an additional pre-treatment step to the existing water treatment plant at Wieliszew. For that purpose, and bearing in mind an integrated process design, the company has performed pilot-scale experiments with DAF installed prior to a process line identical with the existing full-scale plant. The experimental flow is about 10 m3/h.
Arsenic treatment technology for groundwaters
Authors: Selvin N. , Upton J. , Sims J. , Barnes J. 
Published: May 2018

The new United Kingdom drinking water standard of 10 μg/l arsenic will become a statutory obligation in 2003. To comply with the new standard, Severn Trent Water will require a new treatment process to be installed at 17 groundwater sites. The Company embarked on a development programme in 1995, with pilot studies commencing in 1996. Investigations have covered a range of potential treatment technologies including coagulation, ion exchange, reverse osmosis and adsorption. Adsorption with granular ferric media was found to be the best available technology for treating groundwater in Severn Trent.
The paper details the development work undertaken, which has focused on the evaluation of aluminium and ferric based granular medias. This has enabled the design and construction of the first arsenic adsorption plant in the UK, with an output of 20 Ml/d.
OTTER mathematical process simulation of potable water treatment
Authors: Head R. , Shepherd D. , Butt G. , Buck G. 
Published: May 2018

Process modelling has been used for many years in the chemical engineering field and more recently has become well established for as a tool for analysing and optimising the performance of wastewater treatment works. In the clean water area, models are routinely used for simulating distribution networks. In contrast, however, the use of modelling tools on potable water treatment works is relatively new and has yet to become well established. A range of tools have been suggested, including artificial neural networks, computational fluid dynamics and process simulation.
WRc have developed a dynamic simulation package for predicting the performance of water treatment works, via models of individual processes. The software has a range of uses, including process and works optimisation, operational decision support, as a design aid and for training engineers and operators. The models are dynamic so that they predict the response of the treatment works to changes in flow, raw water quality and process operating conditions.
The software has been used in a wide variety of applications, including optimising process plant operation to minimise cost and to investigate the reasons why a treatment works failed to meet its design criteria at the maximum design throughput.
Disinfection effects on E. coli using TiO2/UV and solar light system
Authors: Cho I.-H. , Moon I.-Y. , Chung M.-H. , Lee H.-K. , Zoh K.-D. 
Published: May 2018

First, a continuous flow TiO2/UV reactor was designed and developed in order to examine E. coli disinfection effect using UV light. The optimum conditions for disinfection such as flow rate, light intensity, TiO2 concentration, initial E. coli concentration were examined. The results are as follow (i) The use of the quartz device and TiO2 (anatase) resulted in killing of E. coil within minutes. (ii) Photocatalytic disinfection with UV light in the presence of TiO2 more effectively killed E. coli than UV or TiO2 adsorption only. (iii) As flow rate increased, the survival ratio of E. coli decreased, but over 3 L/min of flow rate, the efficiency was limited. (iv) E. coli survival ratio decreased linearly with increasing UV light intensity. (v) The dosage of TiO2 affected the E. coli disinfection efficiency, and above 0.1 wt% TiO2 concentration, the disinfection was less effective because TiO2 particles may result in screening off the light. (ri) The disinfection reaction follows first-order kinetics.
Secondly, outdoor experiments with natural sunlight instead of artificial UV light in TiO2 reactors were also conducted to investigate alternative energy source applicability on E. coli disinfection. It is found that the presence of clouds in the sky markedly increased the time required for killing E. coli and the bacteria cells also disappeared with a first-order kinetics. On the basis of these experimental observations, the disinfection of E. coli using TiO2 under solar light irradiation can be a feasible application of the advanced oxidation process.