bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical approach to determine the salinized ground water flow path and hydrogeochemical features around the underground LPG cavern, Korea
Authors: Lee Jeongho , Kim Ji‐Hoon , Kim Hun‐Mi , Chang Ho‐Wan 
Published: July 2007

AbstractThe ground water flow path of the coastal area in the Yellow Sea, Korea, was interpreted using both the cross‐correlation analysis of hydraulic properties and the principal component analysis (PCA) of ground water chemistry. Data was obtained from observation wells in the underground liquefied petroleum gas (LPG) cavern constructed in the coastal area of Pyeongtaek. Cross‐correlation results showed that the operating pressure became more influenced on artificial factors for the variation of the groundwater level of the study area (45–66% of correlation coefficient) even though its affecting area was limited to the region with fractures or faults, and also showed that the delay time from the variation of operating pressure to the fluctuation of ground water level were relatively long periods (28–31 days). Three hydrogeochemical events (encrusted cement dissolution, host rock dissolution, and seawater intrusion), which were dominantly influenced on ground water quality, could be induced from the result of PCA. Quantitative evaluation for these events using the mixed equation with principal component scores suggest that the dissolution of encrusted cement materials was the predominant factor (39·0% of the total mixed proportion) to change the chemical composition of the seepage water during the ground water flow from the observation wells to the cavern. Integration of the statistical results also imply that ground water flow and hydrogeochemistry were predominantly affected by artificial factors such as cavern operation pressure and dissolution of encrusted cement materials, which were interdependent factors on the observation wells with high cross‐correlation coefficients and pH. Copyright © 2007 John Wiley & Sons, Ltd.
Modified hydrograph method for arid regions
Authors: Şen Zekai 
Published: July 2007

AbstractThere is a real need for more research on regionalization of flood estimation methods in arid zones. Such estimations are important because reliable long‐term storm rainfall and corresponding runoff measurements are commonly unavailable. This is the situation in many parts of the Kingdom of Saudi Arabia. Hence, it is necessary to develop a new approach, one that suits the conditions found in the Kingdom, which depend on available, but incomplete measurements and catchment morphological features.In this paper, a modified methodology based on the classical Snyder approach is proposed and it is referred to as the Saudi Geological Survey (SGS) approach in order to reflect works of this kind within the Survey. The basis of the methodology has two phases, namely, logical and empirical. The former phase is valid for any part of the world whether humid or arid, but the latter phase is location specific, which in the case of this paper, is the Arabian Peninsula. The application of the methodology is presented for Wadi Baysh, a major wadi in the south‐western part of the Kingdom. Furthermore, a synthetic unit hydrograph (UH) methodology based on a Gamma distribution function is also presented with applications to some of the Wadi Baysh sub‐basins. For this purpose, a dimensionless UH has been obtained, which is special for the area. Copyright © 2007 John Wiley & Sons, Ltd.
Impact of septic tank systems on local groundwater quality and water supply in the Pearl River Delta, China: case study
Authors: Lu Yintao , Tang Changyuan , Chen Jianyao , Sakura Yasuo 
Published: July 2007

AbstractLocated at southern coast of China, the Pearl River Delta (PRD) is facing serious water problems in both quantity and quality after its rapid urbanization in the last decade. Most remarkably, the local groundwater, that was used to be the source of drinking water before the urbanization was polluted due to poor management of the septic tanks. In order to study the effects of suburban development on local groundwater flow and water quality in the PRD region, Fengcun of Guangzhou has been chosen as the study area. In Fengcun, drinking water was groundwater before the 1990s, but now piped reservoir water is used by each family because the groundwater has been polluted. This study clarifies the source and process of the groundwater pollution from septic tanks using isotopic and geochemical characteristics, especially nitrate (NO3−) concentrations. Water samples were collected from the wells and ponds in Fengcun in March and July 2005 and in July 2006. Based on the pe–pH diagram, NO3− and ammonium of groundwater are from the effect of human activities, rather than from nitrification and ammonification of N2. NO3− pollution of groundwater is from point sources, and NO3− concentrations decrease from northeast to southwest. Groundwater is polluted rapidly by the leakage of septic tanks. NO3− concentrations of pollution sources were lower than 20 mg l−1 in March 2005, but had increased to about 120 mg l−1 in July 2006. This implies that groundwater protection should be strengthened in rural areas of the PRD. Copyright © 2007 John Wiley & Sons, Ltd.
Basin‐scale stream‐flow forecasting using the information of large‐scale atmospheric circulation phenomena
Authors: Maity Rajib , Nagesh Kumar D. 
Published: July 2007

AbstractIt is well recognized that the time series of hydrologic variables, such as rainfall and streamflow are significantly influenced by various large‐scale atmospheric circulation patterns. The influence of El Niño‐southern oscillation (ENSO) on hydrologic variables, through hydroclimatic teleconnection, is recognized throughout the world. Indian summer monsoon rainfall (ISMR) has been proved to be significantly influenced by ENSO. Recently, it was established that the relationship between ISMR and ENSO is modulated by the influence of atmospheric circulation patterns over the Indian Ocean region. The influences of Indian Ocean dipole (IOD) mode and equatorial Indian Ocean oscillation (EQUINOO) on ISMR have been established in recent research. Thus, for the Indian subcontinent, hydrologic time series are significantly influenced by ENSO along with EQUINOO. Though the influence of these large‐scale atmospheric circulations on large‐scale rainfall patterns was investigated, their influence on basin‐scale stream‐flow is yet to be investigated. In this paper, information of ENSO from the tropical Pacific Ocean and EQUINOO from the tropical Indian Ocean is used in terms of their corresponding indices for stream‐flow forecasting of the Mahanadi River in the state of Orissa, India. To model the complex non‐linear relationship between basin‐scale stream‐flow and such large‐scale atmospheric circulation information, artificial neural network (ANN) methodology has been opted for the present study. Efficient optimization of ANN architecture is obtained by using an evolutionary optimizer based on a genetic algorithm. This study proves that use of such large‐scale atmospheric circulation information potentially improves the performance of monthly basin‐scale stream‐flow prediction which, in turn, helps in better management of water resources. Copyright © 2007 John Wiley & Sons, Ltd.
Missing role of groundwater in water and nutrient cycles in the shallow eutrophic lake Kasumigaura, Japan
Authors: Nakayama Tadanobu , Watanabe Masataka 
Published: July 2007

AbstractA process‐based model was developed, NICE‐LAKE (NIES (National Institute for Environmental Studies) Integrated Catchment‐based Ecohydrology), which includes interactions between surface water, canopy, unsaturated water, aquifer, lake and rivers, and used it to model the shallow eutrophic Lake Kasumigaura in Japan. By estimating the spatial distribution of the hydrological cycle, the model shows that groundwater withdrawal greatly affects groundwater distribution and seepage and indirectly influences lake water level. The simulated seepage agrees excellently with the budget‐derived value calculated from the observed groundwater level, lake level and isotope analyses. The model showed that groundwater seepage and groundwater concentrations are important contributors to the eutrophication of Lake Kasumigaura, an important contribution not recognized in previous studies of the lake. Groundwater entering the lake from the north side is contaminated with high concentrations of nitrate and ammonia from intensive pig and cattle raising and cultivated fields. The simulation showed that this high nitrogen load plays an important role in the eutrophication of the lake (the nitrogen load in inflowing groundwater is 30% of river inflow and 4 times that from wastewater treatment plants) in spite of government policies to prevent overland flow of nutrients into the lake. Our results show that NICE‐LAKE is a powerful tool for forecasting how the water quality of the lake will be affected by the (illegal) disposal of animal excreta in the surrounding open fields. Copyright © 2007 John Wiley & Sons, Ltd.
Quantifying nitrogen cycling beneath a meander of a low gradient, N‐impacted, agricultural stream using tracers and numerical modelling
Authors: Van der Hoven Stephen J. , Fromm Nicholas J. , Peterson Eric W. 
Published: July 2007

AbstractIn watersheds impacted by nitrate from agricultural fertilizers, nitrification and denitrification may be decoupled as denitrification in the hyporheic zone is not limited to naturally produced nitrate. While most hyporheic research focuses on the 1–2 m of sediment beneath the stream bed, there are a limited number of studies that quantify nitrogen (N) cycling at larger hyporheic scales (10s of metres to kms). We conducted an investigation to quantify N cycling through a single meander of a low gradient, meandering stream, draining an agricultural watershed. Chemistry (major ions and N species) and hydrologic data were collected from the stream and groundwater beneath the meander. Evidence indicates that nearly all the shallow groundwater flowing beneath the meander originates as stream water on the upgradient side of the meander, and returns to the stream on the downgradient side. We quantified the flux of water beneath the meander using a numerical model. The flux of N into and out of the meander was quantified by multiplying the concentration of the important N species (nitrate, ammonium, dissolved organic nitrogen (DON)) by the modelled water fluxes. The flux of N into the meander is dominated by nitrate, and the flux of N out of the meander is dominated by ammonium and DON. While stream nitrate varied seasonally, ammonium and DON beneath the meander were relatively constant throughout the year. When stream nitrate concentrations are high (>2 mg litre−1), flow beneath the meander is a net sink for N as more N from nitrate in stream water is consumed than is produced as ammonium and DON. When stream nitrate concentrations are low (<2 mg litre−1), the flux of N entering is less than exiting the meander. On an annual basis, the meander hyporheic flow serves as a net sink for N. Copyright © 2007 John Wiley & Sons, Ltd.
Comparing a 1D hydraulic model with a 2D hydraulic model for the simulation of extreme glacial outburst floods
Authors: Alho Petteri , Aaltonen Juha 
Published: July 2007

AbstractGlacial outburst floods (jökulhlaups) destroy a significant amount of infrastructure in proglacial areas. Nevertheless, few studies have simulated extreme jökulhlaup inundation using hydraulic modelling. In this study, we demonstrate the capability of one‐dimensional jökulhlaup simulation (HEC‐RAS modelling software) and compare simulation results with those from a two‐dimensional finite element model (TELEMAC‐2D modelling software) to determine the potential and limitations of one‐dimensional modelling for jökulhlaup simulations. In both models, a pre‐defined hydrograph was used as an upstream boundary condition for the jökulhlaup, which was simulated on the Möðrudalur floodplain, northeast Iceland. An unsteady flow simulation of the rising stage of the flood (5 h 15 min) was undertaken with both models to produce maps of flood inundation and flow depth. The study shows that simulations had a 200 m horizontal difference in inundated area at the peak discharge stage. Additional differences were also detected in the rising stage of the hydrograph. The most significant differences between the models was found at the time when the front of the jökulhlaup inundated a new area through a sinuous gorge, or when inundation took place through a complex flow route (maximum difference ∼1800 m). This study demonstrates that one‐dimensional modelling of jökulhlaup propagation provides results broadly comparable to data derived from more complex simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Storm runoff and sediment losses from forest clearcutting and stand re‐establishment with best management practices in East Texas, USA
Authors: McBroom Matthew W. , Beasley R. Scott , Chang Mingteh , Ice George G. 
Published: July 2007

AbstractNine small (2·5 ha) and four large (70–135 ha) watersheds were instrumented in 1999 to evaluate the effects of intensive silvicultural practices with best management practices (BMPs) on runoff and stream water quality in the Western Gulf Coastal Plain of East Texas, USA. Two treatments were implemented in 2002: a conventional treatment with clearcutting and herbicide site preparation, and an intensive treatment that added subsoiling, fertilization and a release herbicide application. Watershed effects were compared with results from a previously conducted study on the same watersheds in 1981, in which two combinations of harvesting and mechanical site preparation without BMPs were evaluated. Due to the reduction in evapotranspirational demand, total storm runoff increased on all six treated small watersheds following harvest by 0·94 to 13·73 cm in 2003. Runoff increases were not statistically significant on the treated large watersheds. Total first‐year sediment loss was significantly greater on two of the conventional and one of the intensive small watersheds. The greatest first‐year increase was 540·1 kg ha−1, only one‐fifth of that observed on these watersheds from shearing and windrowing without BMPs in 1981. First‐year sediment loss was significantly greater on the intensive large watershed following harvest, but not on the conventional large watershed. These data suggest that BMPs are very effective in reducing potential water quality impacts from intensive silvicultural practices. Copyright © 2007 John Wiley & Sons, Ltd.
The influence of elevation error on the morphometrics of channel networks extracted from DEMs and the implications for hydrological modelling
Authors: Lindsay John B. , Evans Martin G. 
Published: July 2007

AbstractStream network morphometrics have been used frequently in environmental applications and are embedded in several hydrological models. This is because channel network geometry partly controls the runoff response of a basin. Network indices are often measured from channels that are mapped from digital elevation models (DEMs) using automated procedures. Simulations were used in this paper to study the influence of elevation error on the reliability of estimates of several common morphometrics, including stream order, the bifurcation, length, area and slope ratios, stream magnitude, network diameter, the flood magnitude and timing parameters of the geomorphological instantaneous unit hydrograph (GIUH) and the network width function. DEMs of three UK basins, ranging from high to low relief, were used for the analyses. The findings showed that moderate elevation error (RMSE of 1·8 m) can result in significant uncertainty in DEM‐mapped network morphometrics and that this uncertainty can be expressed in complex ways. For example, estimates of the bifurcation, length and area ratios and the flood magnitude and timing parameters of the GIUH each displayed multimodal frequency distributions, i.e. two or more estimated values were highly likely. Furthermore, these preferential estimates were wide ranging relative to the ranges typically observed for these indices. The wide‐ranging estimates of the two GIUH parameters represented significant uncertainty in the shape of the unit hydrograph. Stream magnitude, network diameter and the network width function were found to be highly sensitive to elevation error because of the difficulty in mapping low‐magnitude links. Uncertainties in the width function were found to increase with distance from outlet, implying that hydrological models that use network width contain greater uncertainty in the shape of the falling limb of the hydrograph. In light of these findings, care should be exercised when interpreting the results of analyses based on DEM‐mapped stream networks. Copyright © 2007 John Wiley & Sons, Ltd.
Quantifying the impact of soil water repellency on overland flow generation and erosion: a new approach using rainfall simulation and wetting agent on in situ soil
Authors: Leighton‐Boyce G. , Doerr S. H. , Shakesby R. A. , Walsh R. P. D. 
Published: July 2007

AbstractThe conventional view of soil water repellency is that it promotes overland flow and soil erosion, but this is not always borne out by observations. This study aimed to isolate the effects of repellency on long‐unburnt and recently burnt terrain on infiltration, overland flow and erosion at the small plot scale (0·36 m2). Rainfall simulations (30 min; intensity 100 mm h−1), using untreated water, and water treated with surfactants to eliminate repellency, were conducted on in situ repellent soils in fire‐prone Eucalyptus globulus plantations, north‐central Portugal at (i) a long‐unburnt site with and without litter, and (ii) a recently burnt site. On long‐unburnt terrain, the mean overland flow coefficient (33%) was 16 times higher and mean slopewash was 23 times higher under repellent compared with wettable conditions. On recently burnt terrain, no overland flow was recorded under wettable conditions, while under repellent conditions the mean coefficient was 70%. The water storage capacity of the litter layer under 10‐year‐old eucalyptus stands for dry antecedent conditions was at least 3 mm water depth per cm litter depth, implying at least a delay to the onset of overland flow. Severe repellency (36% ethanol) was found to persist through a 30‐min storm (100 mm h−1) when a litter layer was present. A continuous wetting front was observed in the upper ∼1 cm of exposed soil, indicating a breakdown in repellency at the time of observation. Below ∼1 cm, repellent, dry soil conditions generally persisted through the simulated storm event. A major implication is that prediction of hydrological impacts of repellency must also take into account the infiltration characteristics of any litter layer and any non‐repellent soils, if present. Copyright © 2007 John Wiley & Sons, Ltd.
The nature of wetting on urban soil samples: wetting kinetics and evaporation assessed from sessile drop shape
Authors: Diehl Doerte , Schaumann Gabriele E. 
Published: July 2007

AbstractThe understanding of soil water repellency in its complexity requires knowledge of the mechanisms leading to changes in surface characteristics. Wetting kinetics may serve as means to investigate the origin of soil water repellency, but have been scarcely investigated yet. We observe the wetting kinetics of soil samples from two locations via the time‐dependent shape of sessile drop (TISED) at three temperatures.We show that drop penetration may be exceeded by evaporation for high water drop penetration time (WDPT). The time‐dependent change of drop shape and apparent contact angle is explained by surface hydrophilisation including the change from Cassie‐Baxter into Wenzel's state. We identify principal differences in the nature of water repellency between the two investigated locations: Only the samples from the former sewage field, Buch, lose most initial differences in wettability upon air drying and storage. Wetting of these samples requires an activation energy of 65–94 kJ mol−1, indicating chemical reactions as rate‐limiting step. In contrast, wetting of the samples from the inner city park, Tiergarten, requires an activation energy of 42 kJ mol−1for the repellent and 8–20 kJ mol−1for the wettable samples, which suggests physico‐chemical and physical processes as rate‐limiting steps.Our study shows for the first time that the process of soil wetting can be monitored by TISED assessment, and that assessment of the temperature dependence of the wetting kinetics allows distinguishing between different natures of wetting and soil water repellency. It therefore represents a novel approach to investigate wetting processes. Combination of such approaches with spectroscopic investigations will help to deepen our understanding on possible causes of water repellency. They further help to understand the great variety of suggested causes of repellency and indicate locational material‐specific effects rather than one general cause for water repellency. Copyright © 2007 John Wiley & Sons, Ltd.
Influence of biofilms on the water repellency of urban soil samples
Authors: Schaumann Gabriele E. , Braun Burga , Kirchner Dörte , Rotard Wolfgang , Szewzyk Ulrich , Grohmann Elisabeth 
Published: July 2007

AbstractWater repellency is an important phenomenon in soil systems and is influenced by physical, chemical and biological factors. Studies on the influence of bacteria or surface‐attached bacteria (biofilms) on soil water repellency are rare.In this study, we investigated the influence of hydrophilic and hydrophobic bacteria on soil wettability. Three different soil bacteria, Variovorax paradoxus, Bacillus sphaericus and an α‐Proteobacterium, were investigated in different states (vegetative cells and spores in the case of Bacillus sphaericus). The bacteria, isolated from urban soils in the Berlin Tiergarten Park and from a sewage field (in Berlin‐Buch), were grown in a bioreactor on sterilized soil samples and in batch cultures on four different synthetic materials with hydrophobic and hydrophilic surfaces, to form biofilms. Surface hydrophobicity of the overgrown material was determined by the water contact angle, and cell surface characteristics of bacteria were measured using the zeta potential and a hexadecane‐two‐phase‐system.The α‐Proteobacterium and Variovorax paradoxus were classified as hydrophobic, and Bacillus sphaericus was classified as hydrophilic. Contact angles of the overgrown synthetic materials showed a significant influence of the respective material, but differences between the bacteria were not significant. The differences between the materials may be due to effects of the material on biofilm growth or EPS properties. EPS form biofilm matrices and are mainly responsible for aggregate cohesion. The bacterial EPS of the hydrophobic α‐Proteobacterium were more hydrophilic than the cell walls, while those of Bacillus sphaericus were less hydrophilic. In contrast to the artificial materials, differences in contact angle for the inoculated soil sample showed significant differences between the bacterial strains. The α‐Proteobacterium was able to hydrophobize the soil sample, while Bacillus sphaericus showed significant hydrophilization. The results clearly demonstrate the effect of bacterial biofilms on soil wettability. Copyright © 2007 John Wiley & Sons, Ltd.