Hydrogeological Regions Research Articles

Zmienność wydajności wybranych źródeł Polski i środkowej Europy w latach 2003–2014

Artykuł nie zawiera streszczenia w języku polskim.

Levels of major and trace elements, including rare earth elements, and ²³⁸U in Croatian tap waters.

Concentrations of 46 elements, including major, trace, and rare earth elements, and (238)U in Croatian tap waters were investigated. Selected sampling locations include tap waters from various hydrogeological regions, i.e., different types of aquifers, providing insight into the range of concentrations of studied elements and (238)U activity concentrations in Croatian tap waters. Obtained concentrations were compared with the Croatian maximum contaminant levels for trace elements in water intended for human consumption, as well as WHO and EPA drinking water standards. Concentrations in all analyzed tap waters were found in accordance with Croatian regulations, except tap water from Šibenik in which manganese in concentration above maximum permissible concentration (MPC) was measured. Furthermore, in tap water from Osijek, levels of arsenic exceeded the WHO guidelines and EPA regulations. In general, investigated tap waters were found to vary considerably in concentrations of studied elements, including (238)U activity concentrations. Causes of variability were further explored using statistical methods. Composition of studied tap waters was found to be predominately influenced by hydrogeological characteristics of the aquifer, at regional and local level, the existing redox conditions, and the household plumbing system. Rare earth element data, including abundances and fractionation patterns, complemented the characterization and facilitated the interpretation of factors affecting the composition of the analyzed tap waters.

Stream and shallow groundwater nutrient concentrations in an Ozark forested riparian zone of the central USA

Characterizing spatiotemporal variations in surface water (SW)–shallow groundwater (GW) nutrient concentrations is important to predict stream ecosystem responses to disturbance. Unfortunately, there is a lack of such information from mixed-deciduous semi-karst hydro-geological regions. Nitrate (NO3−), total phosphorous (P), potassium (K) and ammonium (NH4+) concentrations were monitored in a case study between an Ozark stream and riparian hardwood forest GW over the 2011 water year in the central USA. Average SW NO3−, P, K and NH4+ concentrations were 0.53, 0.13, 3.29 and 0.06 mg L−1, respectively. Nine meters from the streambank, average GW NO3− concentration was 0.01 mg L−1, while P, K and NH4+ concentrations were 0.03, 1.7 and 0.04 mg L−1, respectively. Hyperbolic dilution model results indicated that NO3− and K exhibited dilution behavior, while NH4+ had a concentration effect and P was hydrologically constant. Observed seasonal NO3− concentration patterns of winter maxima and summer minima in SW (1.164 and 0.133 mg L−1) and GW (0.019 and 0.011 mg L−1) were supported by previous studies yet exhibited distinct semi-karst characteristics. Results indicate that in addition to relatively low residence time, lower nutrient concentrations in GW (relative to SW) may suggest that shallow GW flow processes are important for vegetation removal and retention of nutrients from streams in semi-karst shallow groundwater systems of the central USA.

Detection of field significant long-term monotonic trends in spring yields

Trend analysis is a frequently used tool in hydrology and climatology for the identification of long-term changes. However, studies are usually only oriented on local trends. This paper rather focuses on the spatial application of trend analysis in groundwater data. For this purpose, a modification of the Mann-Kendall test was developed, based on the trend-free pre-whitening approach. This method was successfully tested on 157 series of yields from headwater springs collected in Czechia during the 1971–2007 period. The analysis was done separately for year, each season and each month. Field significant trends in spring yields were identified in hydrogeological regions. The results showed that the field significant trends are outnumbered when cross-correlation is not taken into account. In the case of annual series, 4 of 18 hydrogeological regions investigated showed a significant decreasing trend after corrections for cross-correlation, compared to 12 regions with field significant trend when not considering cross-correlation.

Spatiotemporal Surface-Groundwater Interaction Simulation in South Florida

South Florida ecosystem is dictated by a large wetland, karst hydrogeology and extended coastal boundary with the Atlantic Ocean. The risks related to the ecosystem include: disruption of groundwater flow as a result of frequent sinkhole formation; flooding in urban areas as a result of the shallow water table; saltwater intrusion from the ocean; and excessive nutrient load to surficial water bodies and subsequently eutrophication because of the intensive utilization of wetlands for nutrient removal. Attempts to understand eco-hydrological processes primarily focus on extensive monitoring and use of distributed hydrological models. However, the relatively flat nature of the region and also the extended coastal boundary with the ocean, makes watershed-based approaches less realistic. A regional spatiotemporal groundwater level modeling approach was attempted using a Dynamic Factor Analysis (DFA) method. The daily water levels of 13 monitoring well sites from major hydrogeologic regions and different land uses were used to conduct the DFA analysis, and six dynamic factors were identified using minimum Akaike Information Criterion (AIC). Further exploratory analysis to relate the dynamic factors with physically attributable explanatory variables has helped to identify five of the major factors that govern the groundwater dynamics in south Florida. Three of the factors were attributable to the Lake Kissimmee water level in the north, Caloosahatchee River water level in the west, and Hillsboro canal in the east. The other two factors identified were the regional averaged rainfall and soil moisture. The spatiotemporal simulation involved interpolation of the loadings of the dynamic factors using an inverse distance weighted method and convoluting with the dynamic factors. The result has shown a good fit with the maximum RMSE of 0.12 m. Retrieval of rainfall, soil moisture, and surface water level from satellite imagery makes spatiotemporal modeling of the groundwater level achievable.

Assessment of natural arsenic in groundwater in Cordoba Province, Argentina

Groundwater in the central part of Argentina contains arsenic concentrations that, in most cases, exceed the value suggested by international regulations. In this region, Quaternary loessical sediments with a very high volcanic glass fraction lixiviate arsenic and fluoride after weathering. The objectives of this study are to analyze the spatial distribution of arsenic in different hydrogeological regions, to define the naturally expected concentration in an aquifer by means of hydrogeochemistry studies, and to identify emergent health evidences related to cancer mortality in the study area. The correlation between arsenic and fluoride concentrations in groundwater is analyzed at each county in the Cordoba Province. Two dimensionless geoindicators are proposed to identify risk zones and to rapidly visualize the groundwater quality related to the presence of arsenic and fluoride. A surface-mapping system is used to identify the spatial variability of concentrations and for suggesting geoindicators. The results show that the Chaco-Pampean plain hydrogeologic region is the most affected area, with arsenic and fluoride concentrations in groundwater being generally higher than the values suggested by the World Health Organization (WHO) for drinking water. Mortality related to kidney, lung, liver, and skin cancer in this area could be associated to the ingestion of arsenic-contaminated water. Generated maps provide a base for the assessment of the risk associated to the natural occurrence of arsenic and fluoride in the region.

Vulnerability and risk evaluation of agricultural nitrogen pollution for Hungary's main aquifer using DRASTIC and GLEAMS models

In recent years, the significant improvement in point source depuration technologies has highlighted problems regarding, in particular, phosphorus and nitrogen pollution of surface and groundwater caused by agricultural non-point (diffuse) sources (NPS). Therefore, there is an urgent need to determine the relationship between agriculture and chemical and ecological water quality. This is a worldwide problem, but it is particularly relevant in countries, such as Hungary, that have recently become members of the European Community. The Italian Foreign Ministry has financed the PECO (Eastern Europe Countries Project) projects, amongst which is the project that led to the present paper, aimed at agricultural sustainability in Hungary, from the point of view of NPS. Specifically, the aim of the present work has been to study nitrates in Hungary's main aquifer. This study compares a model showing aquifer intrinsic vulnerability to pollution (using the DRASTIC parameter method; Aller et al. [Aller, L., Truman, B., Leher, J.H., Petty, R.J., 1986. DRASTIC: A Standardized System for Evaluating Ground Water Pollution Potential Using Hydrogeologic Settings. US NTIS, Springfield, VA.]) with a field-scale model (GLEAMS; Knisel [Knisel, W.G. (Ed.), 1993. GLEAMS—Groudwater Leaching Effects of Agricultural Management Systems, Version 3.10. University of Georgia, Coastal Plain Experimental Station, Tifton, GA.]) developed to evaluate the effects of agricultural management systems within and through the plant root zone. Specifically, GLEAMS calculates nitrate nitrogen lost by runoff, sediment and leachate. Groundwater monitoring probes were constructed for the project to measure: (i) nitrate content in monitored wells; (ii) tritium ( 3H) hydrogen radioisotope, as a tool to estimate the recharge conditions of the shallow groundwater; (iii) nitrogen isotope ratio δ 15N, since nitrogen of organic and inorganic origin can easily be distinguished. The results obtained are satisfactory, above all regarding the DRASTIC evaluation method, which is shown to satisfactorily explain both low and high aquifer vulnerability, and furthermore proves to be a good tool for zoning hydrogeological regions in terms of natural system susceptibility to pollution. The GLEAMS model, however, proves not to be immediately usable for predictions, above all due to the difficulty in finding sufficient data for the input parameters. It remains a good tool, but only after an accurate validation, for decision support systems, in the specific case to integrate intrinsic vulnerability, from DRASTIC (or similar methods), with land use nitrate loads from GLEAMS, or similar methods. The PECO project has proved a positive experience to highlight the fundamental points of a decision support system, aimed to mitigate the nitrate risk for groundwater coming from Hungarian agricultural areas.

System analysis to estimate subsurface flow: from global level to the State of Minnesota

Stream runoff data globally and in the state of Minnesota were used to estimate subsurface water flow. This system approach is based, in principal, on unity of groundwater and surface water systems, and it is in stark contrast to the traditional deterministic approach based on modeling. In coordination with methodology of system analysis, two levels of study were used to estimate subsurface flow. First, the global stream runoff data were assessed to estimate the temporal–spatial variability of surface water runoff. Factor analysis was used to study the temporal–spatial variability of global runoff for the period from 1918 to 1967. Results of these analysis demonstrate that the variability of global runoff could be represented by seven major components (factor scores) that could be grouped into seven distinct independent grouping from the total of 18 continental slopes on the Earth. Computed variance value in this analysis is 76% and supports such analysis. The global stream runoff for this period is stationary, and is more closely connected with the stream flow of Asia to the Pacific Ocean as well as with the stream runoff of North America towards the Arctic and Pacific Oceans. The second level examines the distribution of river runoff (annual and for February) for various landscapes and the hydrogeological conditions in the State of Minnesota (218,000 km2). The annual and minimal monthly rate of stream runoff for 115 gauging stations with a period of observation of 47 years (1935–1981) were used to characterize the spatio-temporal distribution of stream runoff in Minnesota. Results of this analysis demonstrate that the annual stream runoff rate changes from 6.3, towards 3.95, and then to 2.09 l s–1 km–2 (the difference is significant based on Student's criteria). These values in Minnesota correspond to ecological provinces from a mixed forest province towards the broadleaf forest and to prairie province, respectively. The distribution of minimal monthly stream runoff rate (February runoff) is controlled by hydrogeological systems in Minnesota. The difference between the two hydrogeological regions, Precambrian crystalline basement and Paleozoic artesian basin of 0.83 and 2.09 l/s/km2, is statistically significant. Within these regions, the monthly minimal runoff (0.5 and 1.68, and 0.87 and 3.11 l s–1 km–2 for February, respectively) is also distinctly different for delineated subregions, depending on whether or not the Quaternary cover is present. The spatio-temporal structure that emerges could thus be used to generate river runoff and subsurface flow maps at any scale – from the global level to local detail. Such analysis was carried out in Minnesota with the detailed mapping of the subsurface flow for the Twin Cities Metropolitan area.

A regional model of low flow for southern Taiwan

AbstractThe primary purpose of this study is to develop regional models of the lower part of flow duration curves (LPFDCs) to synthesize low‐flow characteristics at ungauged sites in southern Taiwan. Because of the close relationship between low streamflow regimes and hydrogeological features, the model development first involved delimiting homogeneous hydrogeological regions by using two‐step cluster analysis. Each homogeneous region was then discriminated by an equation developed on the basis of its hydrogeological features, which was then used to determine which of three sets of regional LPFDC models would be appropriate for a particular ungauged site. Each of the three sets of regional LPFDC models were developed using both conventional multivariate statistical regression and fuzzy regression. Thirty‐four stream‐gauged watersheds located in southern Taiwan provide the data set. The study results reveal that the regional LPFDC models developed in this study could be applied reasonably at ungauged sites. Copyright © 2002 John Wiley & Sons, Ltd.

Formation of subsurface waters of oil and gas-bearing basins, according to isotopic data

The author examines certain aspects of the origin and formation of subsurface waters of oil- and gas-bearing basins. An investigation of the isotopic composition of the hydrogen of the waters revealed that the waters of these basins are of the sedimentation type, diluted with meteoric waters during periods in which ancient infiltration regimes were operative. Within the limits of the oil- and gas-bearing basins they are subdivided into a number of hydrogeological regions corresponding to large tectonic elements, and they are without mutual hydrodynamic links. Regional displacements of water masses within such basins are not observed.

Improving hydrogeological services in the pits of the Borovich refractories combine

The introduction of hydrogeological forecasting techniques allows a timely evaluation to be made of mine-working conditions during extraction, and permits rational measures to be worked out to deal with underground water and ensure stable mining conditions. Hydrogeological analysis of mine exploitation areas allows improved efficiency in the production activities of mining concerns. A basic principle in improving the efficiency of hydrogeological studies of refractory clay deposits during the industrial exploitation stage is that the deposits and individual working areas should be divided up into appropriate hydrogeological regions.

PRINCIPAL TYPES OF HYDROGEOLOGIC STRUCTURES IN THE U.S.S.R.

Different parts of the U. S. S. R. are characterized by highly diverse hydrogeologic conditions which permit the distinction of a great number of hydrogeologic regions. The two principal types are artesian basins and hydrogeologic massifs. Artesian basins include platform and intermontane depressions. Hydrogeologic massifs, where fissure-vein ground waters prevail, are found in the crystalline shield areas. The basins and massifs are subdivided into groups depending on conditions of mineralization, temperature, and other specific features of the ground water. Thus, artesian basins are subdivided into those with fresh water, with salt water and brine, thermal waters, and those of permafrost ice. Hydrogeologic massifs include groups with cold carbonate and radon waters, with thermal sulfur-carbonate waters, with cold and thermal methane waters, and with hydrogen-sulfide waters. The distribution of artesian basins and hydrogeologic massifs, and their subgroups, in the U. S. S. R. is given M. Russell