Cretaceous Aquifer Research Articles

Methane released from groundwater: the source of natural gas accumulations in northern West Siberia

The West Siberian Basin is the largest continental sedimentary basin on earth and contains about one third of the world's conventional reserves of natural gas. From gas compositional and isotope data this gas can be described as a mixture of thermogenic gas from lower Cretaceous rocks ( δ 13 C 1 ≈ −36‰, C 2+, ≈10 vol% ) and almost pure methane (98 vol%) with the relatively light stable carbon isotope signature of −51‰ ( δ 13C 1) on average. The proportion of the isotopically light methane increases from the lower Cretaceous to the top of the Cretaceous hydrocarbon system (top of the Pokur Formation), where the main reservoirs are situated. The composition and the huge volume of gas is difficult to explain with the established models of gas generation in sediments. The hydrogeology of the basin is determined by thick aquifer systems with an almost basin wide lateral continuity. The largest hydrodynamic system is the Cretaceous aquifer, in which 98% of the natural gas is trapped. The groundwater within the Cretaceous aquifer is saturated with the same isotopically light methane as that found in the reservoirs of the Pokur Formation. Based on petrophysieal data a detailed hydrogeological model of the Cretaceous aquifer beneath the largest gas accumulation, the Urengoy gas field, has been developed and the contribution of gas release from groundwater was compared with the volume of gas in the reservoirs. The potential methane release from groundwater has been evaluated as a result of. (1) cooling of sediments in Quaternary times, (2) the lateral gradient of the hydraulic pressure under the gas field and (3) the pressure and temperature decrease due to Cenozoic uplift. The role of Quaternary cooling is insignificant and, according to our calculations, the contribution of the effect by groundwater flow is small. The volume of isotopically light methane released from groundwater due to a Neogene uplift is very large and can explain the entire gas in place. The source of this gas must be located south of the gas field province.

Hydrochemistry and flow modelling of the Aveiro multilayer Cretaceous Aquifer

Detailed hydrogeochemical studies, including the analysis of major, minor and trace elements, and groundwater modelling of the Aveiro Cretaceous coastal aquifer are used to give a better understanding of groundwater flow conditions and the natural geochemical processes within the groundwater flow system. The results show evidence of an aquifer with a very slow chemical kinetics for water-rock interactions as a consequence of the dominant siliciclastic composition of the aquifer sediments. The geochemical evolution of the groundwater composition clearly reflects the silicate nature of the sediments, determined by the very slow dissolution-rate mechanisms of silicate murals. Feldspar dissolution and cation exchange with the aquifer clay minerals control the groundwater chemical composition. Flow modelling has been used to test the validity of the conceptual model of the aquifer and contributed to interpret the regional patterns of the flow system, confirming that the aquifer has limited natural recharge.

Groundwater monitoring to assess the influence of injection of liquid radioactive waste on the Tomsk public groundwater supply, Western Siberia, Russia

Abstract This paper considers the potential impact of the deep injection of liquid radioactive waste (LRW) on the continued operation of the Tomsk public groundwater supply. The close proximity of the LRW injection polygons to the wellfield creates a geoenvironmental conflict, due to the possibility of migration of radionuclides and other toxic components of LRW from the Cretaceous aquifer system used for LRW injection to the Palaeogene aquifer complex used for water supply. Although a significant argillaceous aquitard and a non-utilized buffer aquifer horizon lie between the aquifer systems, there are indications that such inter-aquifer migration may take place, either due to sandy windows in the aquitard or to inadequately sealed well annuli. A major groundwater monitoring network, based on the co-operative use of automated information systems and GIS technologies, has been established. In order to simulate contaminant migration scenarios, the use of variably scaled numerical hydrogeomigrational models is recommended. These would allow prognostic estimations and form a basis for administrative decision-making to minimize damage to the geological environment.

Flow of Formation Waters, Aquifer Characteristics, and Their Relation to Hydrocarbon Accumulations, Northern Alberta Basin

Based on the wealth of data generated by the oil industry, the regional-scale characteristics of rocks, the flow of formation waters, and their relation to hydrocarbon accumulations were analyzed for the northern Alberta basin. The flow of formation waters in several aquifers and aquifer systems separated by intervening aquitards is at steady state and is driven by the present-day topography both on a regional and a local scale. The flow is generally from a recharge area in the southwest at the fold belt and Bovie Lake fault, to discharge in the northeast at the Great Slave Lake, the lowest point in the basin. The flow in Devonian aquifers is in open systems from recharge to discharge areas, whereas the flow in Carboniferous and Cretaceous aquifers is in semi-open systems, discharging into adjacent aquitards. Very high porosity and permeability in places in the Devonian Elk Point aquifer system are due to reefs, fracturing, dolomitization, and karst processes. Very high permeability probably leads to relatively high flow rates along the Presqu'ile barrier reef, resulting in local advective effects on the terrestrial heat transport to the surface. On a regional scale, all of the aquifers are underpressurized due to upstream propagation through high-permeability zones of low hydraulic heads at discharge elevations. The flow pattern is corroborated by salinity distributions, with comparatively lower salinity in each aquifer at recharge in the southwest and at discharge in the northeast caused by mixing with fresher meteoric water, and higher salinity between recharge and discharge areas. Salinity distributions show that the aquifers are not completely flushed of the original formation waters. Dissolution of salt and anhydrite from adjacent strata leads to high salinity in the Elk Point aquifer system and Beaverhill Lake aquifer. Hydrocarbons generated in the southwest in Devonian and Carboniferous strata, at maximum burial depth during the Laramide orogeny, migrated updip to the northeast driven by their own buoyancy and entrained by the flow of formation waters. Unless stratigraphically trapped by reefs and at the edge of semi-open aquifers, migration to the discharge areas led to loss of the volatile components and biodegradation into altered bitumens. The hydrostratigraphy and direction of the flow of formation waters in the northern part of the Alberta basin indicate that hydrocarbons generated in this region did not contribute to the formation of the giant Athabasca oil sand deposit located southeast of the study area.

Aquifer Response to Record Low Barometric Pressures in the Southeastern United States

AbstractA late‐winter cyclone classified as one of the most intense of the 20th century moved across the Southeastern states of Georgia and South Carolina and onto the Northeast during March 12–14, 1993. Record low barometric pressures were recorded in Augusta, Georgia (28.93 inches of mercury) and Columbia, South Carolina (28.63 inches of mercury) on March 13, 1993, and pressures returned to normal values (near 30 inches of mercury) within one day following these record lows. This relatively unusual event provided an opportunity to examine the attendant water‐level response in continuously monitored ground‐water wells in regional Atlantic Coastal Plain, Piedmont, and Blue Ridge aquifers in the Southeast. Water levels in all wells examined responded inversely to the short duration, extreme drop in barometric pressure. Barometric efficiencies (Δground‐water level/Δbarometric‐pressure level) calculated were dependent on depth to screened‐ or open‐interval midpoint (highest correlation coefficient, r2= 0.89) and, to a lesser extent, total thickness of confining material above the aquifer tapped (highest r2= 0.65). Wells in crystalline‐rock aquifers had a correlation with depth to open‐interval midpoint (r2= 0.89) similar to the sedimentary aquifers examined. The magnitude of barometric efficiency was also strongly related to a well's increased distance from aquifer outcrop areas in the Cretaceous aquifers in South Carolina (r2= 0.95) and the upper Brunswick aquifer in Georgia (r2= 0.90), because these aquifers are more deeply buried toward the coast. This relation between barometric efficiency, well depth, and extent of confinement suggests that barometric efficiency determinations can provide useful information to hydrologists concerned with examining an aquifer's degree of confinement and corresponding isolation from land surface, particularly when the aquifer is used as a source for public supply.

Recharge into Southern High Plains aquifer—possible mechanisms, unresolved questions

The High Plains aquifer in the Southern High Plains (Texas and New Mexico), consisting of Tertiary, Cretaceous, and Triassic formations, has traditionally been considered to be recharged by its uppermost water-bearing unit, the Tertiary Ogallala aquifer. This article provides hydrologic, chemical, and isotopic evidence that in the Southern High Plains: (1) Cretaceous rocks actually contain independent recharge sources; (2) Triassic rocks cannot currently be recharged by the Ogallala aquifer in significant quantities; and (3) in places, both Cretaceous and Triassic aquifers recharge the overlying Ogallala aquifer. On the basis of chemical and isotopic data, playa lakes seem to act as the predominant recharge source of the Ogallala aquifer, suggesting recharge rates greater than 30 mm/yr, as opposed to the much lower rates reported by others. The Cretaceous aquifers are being recharged by cross-formational flow from the Ogallala aquifer but also from overlying Quaternary sands and the underlying Triassic aquifer in eastern New Mexico. Current recharge into the Triassic aquifer may be insignificant.

Identifying Flow Intervals by Pore Geometry and Petrophysics: Middle Trinity Aquifer (Lower Cretaceous Limestone)

A core from the Lower Cretaceous middle Trinity aquifer of southern Kendall County, Texas, was analyzed to compare its petrographic and petrophysical properties to its hydraulic flow characteristics. The analyses helped determine flow intervals in the core. Flow intervals are defined as vertical zones having similar geologic (depositional and diagenetic) history, petrophysical properties, and hydraulic conductivity characteristics. The information gathered from the study of a single core may be integrated with similar data from other cores or well logs to define 'flow units.' Methodology involved visual and image analysis examination of thin sections and epoxy pore casts of samples to evaluate pore geometry (pore size, pore throat size, pore interconnectivity, and pore throat size heterogeneity). Samples were thus grouped into pore-type families. Representative samples from each pore-type family were tested for air and brine permeability, porosity, and mercury injection capillary pressure. Pore throat size distributions obtained from the capillary pressure analyses were compared to the data derived from the pore casts and thin sections. Pore geometry evaluated correlated well with mercury capillary pressure data for the most permeable zone of the core. Geologically, this flow interval consists of a porous, medium-grained peloid grainstone that is characterized by large pores connectedmore » by large pore throats. Wherever present, such pore throat to pore body size ratios enhance flow through the rock. Correlation between pore geometry and capillary pressure data deteriorate in packstones with increasing micrite mud content and wackestones with increasing dolomitization. These lower correlations are due to decreasing pore throat size and increasing pore throat size heterogeneity in these rocks.« less

Predicting the Distribution of Upper Cretaceous Aquifers Using Sea-Level Analysis and Regional Paleogeography, Alabama Coastal Plain

In the inner coastal plain of Alabama, Upper Cretaceous (i.e., Santonian-Maastrichtian) stratigraphic units containing key aquifers dip south at 7m/km; the aquifers consist mainly of porous and permeable barrier-island facies (including upper-shoreface and tidal-pass sands), barrier-related sand facies (including tidal deltas and lagoonal and marine tempestite beds), and shallow-marine sand facies (including offshore bars and conglomerate sandy turbidite tongues). Confining aquitard and aquiclude facies include lagoonal silty clays, shallow-marine glauconitic clays, clayey marls, and marine chalky marls. The gross geometry, thickness, and lateral and vertical distribution of aquifer sands in both the shallow-subsurface and outcrop (i.e., recharge) area is predictable based on regional paleogeographic reconstructions and the regional Late Cretaceous relative sea-level curve. At a local scale, facies maps and shallow-subsurface correlations provide essential data for aquifer exploration and recharge-area protection. For example, in the Eutaw Formation, barrier-island and barrier-related facies developed along a curved east-west striking shoreline; aquifers include shoreline facies, tempestite beds, and turbidite sands. In the younger, northwest-striking Blufftown-Cusseta and Ripley-Providence systems, aquifers are barrier-island and barrier-related (especially tidal-delta) facies.

Aspectos qualitativos da infiltração da vinhaça de cana no aqüífero Bauru

A área estudada está localizada no município de Novo Horizonte, situado no centro-oeste do Estado de São Paulo. Na região ocorrem sedimentos cretáceos do Grupo Bauru que constituem um aqüífero livre, poroso e explorado para fins de abastecimento doméstico e industrial. Sobre este aqüífero, cuja extensão no Estado· de São Paulo é de 104.000 km² , a atividade canavieira tem apresentado um grande crescimento, fazendo com que um grande volume de vinhaça se infiltre no solo e cause uma considerável poluição hídrica, já considerada crítica em certas áreas. Este trabalho enfoca a problemática da infiltração da vinhaça numa área-piloto do aqüífero Bauru. Os resultados obtidos nesta pesquisa caracterizam claramente os impactos que a infiltração da vinhaça causa à água subterrânea, tornando-a inadequada para o consumo humano. Os seguintes parâmetros excederam os padrões de potabilidade: o nitrogênio amoniacal foi encontrado com valores entre >;0,005 e 9,8 mg/l; o magnésio, entre 12,0 e 210,0 mg/l; o alumínio, entre >;0,02 e 23,0 mg/l; o ferro, entre >;0,005 e 60,0 mg/l; o manganês, entre 5,0 e 60,0 mg/l; e o cloreto, entre 4,0 e 640,0 mg/l.

Hydrogeology and hydrochemistry of Cretaceous aquifers, Southern High Plains, U.S.A.

Cretaceous rocks in the Southern High Plains, traditionally considered to be part of the High Plains aquifer and to be recharged by the overlying Ogallala aquifer, actually contain three aquifers with different recharge sources. Two separate subcrop areas of Cretaceous rocks underlie the Ogallala Formation. These subcrops are composed of sandstones, limestones, and shales having a total thickness of as much as 76 m. Three aquifers, the Trinity sandstone, the Edwards limestone, and the Duck Creek-Kiamichi sandstones and limestones, were identified within the Cretaceous section. Wherever the Ogallala aquifer is thin or missing, Cretaceous aquifers are the main water supply. Major recharge sources are (1) percolation through thick surficial alluvial deposits and sand dunes in New Mexico and northwestern Texas and (2) leakage from the underlying Dockum aquifer in eastern New Mexico. Recharge from the overlying Ogallala aquifer is restricted to small parts of the study area. Elsewhere, differences in hydraulic heads and similarities in chemical and isotopic composition suggest cross-formational flow from Cretaceous aquifers into the overlying Ogallala Formation or into the underlying Dockum Group.

Influence of lithology and fluid flow on the temperature distribution in a sedimentary basin: A case study from the Cold Lake area, Alberta, Canada

A detailed study of the groundwater and terrestrial heat flow was carried out over an area of 23,700 km 2 west of Cold Lake, Alberta, which is part of the western Canada sedimentary basin. The information for the study was provided from data from 3100 wells drilled in the area. The screening and processing of thousands of stratigraphic picks, drillstem test data, bottom hole temperatures and formation water chemistry data was performed mainly using a specially designed software package. As a result, every stratigraphic unit is characterized by appropriate hydraulic and thermal parameters. A sequence of aquifers, aquitards and aquicludes was differentiated. The groundwater flow in the Paleozoic aquifers is regional in nature and mainly horizontal. The flow in the Cretaceous aquifers is of intermediate type, mainly downward oriented. In general, the permeability of the Cretaceous and Paleozoic strata has such low values that the fluid velocity is less than 1 cm/yr. The convective heat transport in the hydrostratigraphic sequence is negligible with respect to the conductive heat transfer, as shown by the Peclet number of the fluid and heat flow in porous media. The flow of the terrestrial heat flux from the Precambrian basement of the sedimentary basin to the atmosphere is controlled by the variability in the thermal properties of the formations in the basin. The geothermal gradients were computed by hydrostratigraphic unit using a linear regression fit to the temperature data. As expected, they show higher values for the less conductive layers, and lower values for the more conductive ones. The weighted average, or the integral geothermal gradient of the whole sedimentary column, was computed by considering the difference between the temperature measured at the Precambrian basement and the annual average temperature at the surface. The areal distribution of the integral geothermal gradient (with an average of 22.0 mK/m) shows a strong correlation with the lithology. The areal temperature distribution for each hydrostratigraphic unit was analyzed by mapping the deviation of the measured value from the computed geothermal gradient. The lateral heat flow from warmer to colder areas is one order of magnitude smaller than the vertical heat flow. In the more homogeneous units, the lateral heat flow presents a trend that seems to reflect the geometry and lithology.

Ground‐Water Flow in the Coastal Plain Aquifers of South Carolina

ABSTRACTThe characteristics of the Coastal Plain aquifers of South Carolina are being studied as a part of the Regional Aquifer System Analysis program of the United States Geological Survey. Potentiometric maps were constructed for the Middendorf aquifer of Cretaceous age and for the Floridan aquifer system and its sand facies equivalent, Tertiary sand aquifer, prior to development. Also constructed was a potentiometric decline map for the period prior to development to November 1982 for the Middendorf aquifer. These maps are used to describe the ground‐water flow system.The Coastal Plain aquifers are recharged primarily by precipitation in their outcrop areas. Ground water flows from these areas of recharge, through the aquifers, and discharges to upper Coastal Plain rivers, overlying aquifers as upward leakage, and wells.Ground‐water flow in the Floridan aquifer system and the Tertiary sand aquifer prior to development is generally perpendicular to the coast. Predevelopment flow in the Cretaceous aquifers, however, turns northeastward as it approaches the coast, almost paralleling the coast. The change in flow direction is caused by less effective intervening confining units, the aquifers being closer to the land surface, and the rivers at lower altitudes farther upstream in the vicinity of the North Carolina/South Carolina State line.Water‐level declines in the Cretaceous aquifers have occurred throughout much of the eastern part of the Coastal Plain of South Carolina due to pumpage in the Myrtle Beach and Florence areas. Large areally extensive water‐level declines have also occurred in the Floridan aquifer system in South Carolina due to pumpage in the Savannah, Georgia area.

Geochemistry of Groundwater in Cretaceous Sediments of the Southeastern Coastal Plain of Eastern Mississippi and Western Alabama

Geochemical samples of waters along two hydrologic flow paths in four Upper Cretaceous aquifers of northeastern Mississippi and western Alabama indicate similar geochemical evolution of their respective waters. The waters of the Coker, Gordo, and Eutaw‐McShan aquifers, noncalcareous sands, increase downgradient in dissolved solids and pH, and are dominated by sodium and bicarbonate ions, which generally result from a calcite dissolution‐cation exchange process. Increases in dissolved iron from oxidation reduction reactions followed by decreases in total inorganic carbon from siderite precipitation occur along the flow paths. As the total inorganic carbon increases, carbon 13 (δ13C) generally is enriched in the moving waters, indicating the addition of a predominantly heavy source of carbon, most likely dissolving calcite. In the Coker aquifer δ13C values in the waters become more negative downgradient, resulting from lignite oxidation, followed by δ13C values becoming more positive, resulting from dissolving calcite and perhaps some mixing with brines. In northeastern Mississippi the Ripley aquifer, a calcareous sand, initially contains calcium‐bicarbonate dominated water that evolves to a sodium‐ bicarbonate dominated water downgradient, primarily from the calcite dissolution‐cation exchange process. Feldspar hydrolysis to kaolinite dominates aluminosilicate reactions in the upgradient parts of the aquifers. Authigenesis of smectite clay may be occurring in the deeper, downgradient parts of the aquifers.

Nitrate, Chloride and Dissolved Solids, Ogallala Aquifer, West Texasa

ABSTRACTThe distribution of nitrate, chloride and dissolved solids from ground water from the Ogallala aquifer in a 27‐county area of west Texas illustrates widespread areas of poor water quality. Elements studied increased in concentration from northwest to southeast across the Southern High Plains. Northeast of a line from about Clovis, New Mexico to Lubbock, Texas, nitrate tends to be <45 mg/l, chloride is <20 mg/l, and dissolved solids are <400 mg/l. However, southwest of this line nitrate may exceed 60 mg/l and in some areas exceeds 170 mg/l. Chloride commonly exceeds 500 mg/l and may be >2000 mg/l, and dissolved solids usually exceed 1000 mg/l and may be >8000 mg/l. Regional distribution may be the result of long‐term migration of Ogallala ground water but the present water quality and distribution, as well as time, distance, stratigraphy and permeability, suggest contamination of Ogallala ground water by vertical rather than lateral migration. Most of the high nitrate values (>45 mg/l) occur in areas having sandy soils which have been intensively cultivated, thus leaching of nitrogen‐based fertilizers is suspect. However, the high chloride and dissolved solids, which exist in essentially the same geographic area, probably represent vertical to local lateral seepage of saline water from large alkali lake basins and local vertical migration from saline Cretaceous aquifers.

Problèmes hydrologiques et hydrochimiques du karst du Liban central

SUMMARY The wealth of karst in central Lebanon has permitted the study of the perched aquifer (of the high cenomanien plateau of Kesrouane) in comparison to the Barred limestone aquifer (of the low and middle mountains) and the cretaceous aquifer of the littoral area that contributes of the alimentation of powerful submarine springs. The study of the « ablation cycle » leads to the valuation of the dissolved contents of the meteoric waters, the streaming, percolated, infiltred waters, as well as of the subterranean rivers and the karstic springs. The chimical analyse of rain waters, as soon as they arrive on a karstic reception basin and stream on a distance of 100 meters, gives important results.

Genesis of boron in waters of Cretaceous aquifers in western part of Caucasian piedmont

Genesis of boron in waters of Cretaceous aquifers in western part of Caucasian piedmont

Techniques for Quality‐of‐Water Interpretations from Calibrated Geophysical Logs, Atlantic Coastal Areaa

ABSTRACTIn the fall and winter of 1967–68, a 2,587‐foot test well was drilled at Moore's Bridges Filter Plant, Norfolk, Virginia. The well penetrated rocks of post‐Miocene, late and middle Miocene, late Eocene, Cenomanian, Cenomanian and Albian, Albian and Aptian, and Aptian and Neocomian age.Empirical data must be established in the Tidewater area for the successful calculation of ground‐water quality from calibrated geophysical logs. Chemical analyses of water samples from seven separate zones at depths between 850 feet to 2,500 feet below sea level indicate that the water type changes from a predominantly sodium bicarbonate water above 1,700 feet to a sodium chloride water in the deeper zones. The sodium bicarbonate type water in shallow aquifers must be corrected for divalent cation effects when using the self potential method or for the bicarbonate effect when using the resistivity method of interpretation.Using calibrated geophysical logs, an approximation of the dissolved‐solids and chloride content may be calculated using the formula Rw= Ro/Ff and the appropriate figures in the text. A field formation factor (Ff) of 4.2 is proposed for the Cretaceous aquifers in the Atlantic Coastal area. A K value of 84 should be used to check the validity of the magnitude of the self potential curve for the fresh‐ and brackish‐water aquifers in the Cretaceous. If the amount of dissolved solids is known for the Cretaceous waters, the chloride content may be approximated by the formula Cl = 0.5 (dissolved solids–300), provided the dissolved solids are less than 3,500 mg/l (milligrams per liter), and by the formula Cl = 0.6 (dissolved solids–400), if the dissolved solids are greater than 3,500 mg/l. In the Tidewater area, if the saturated resistivity (Ro) reading on the electric log is less than 25 ohmmeters the total solids and chloride content of the water are probably in excess of Public Health standards for potable water. An empirical method of calculating the quality of water from electric logs is presented.

Water history of Cretaceous aquifers, East Texas Basin

Circumstantial evidence of the history of water in five Cretaceous aquifers is supplied by water analyses comparisons and a study of the ratios of the major ions, Ca 2+, Mg 2+, Na +, Cl −, SO 2− 4 and HCO − 3. Water from each aquifer has distinctive characteristics, but there are interconnections between aquifers, especially near the Mexic-Talco fault zone and at an unconformity that extends across the Sabine uplift. Some piercement salt domes modify formation waters, but most salt domes have little or no noticeable effect. Apparently clay sheaths protect the salt columns from solution. Town water supplies on the north Texas shelf are affected by invasion of hot brine from the Tyler Basin, moving from east to west through the Woodbine Sandstone. This hydrodynamic flow in part accounts for the existence of the giant east Texas field to the west of the Sabine uplift, while similar updip truncated sandstones on the east side of the Sabine uplift are generally barren of oil, even though they occupy the same stratigraphic position as the Woodbine. Ion ratio comparisons show that water in the older, more deeply buried aquifers have been modified more (compared with presentday sea water) than that in younger, less deeply buried aquifers. Although this is generally true, there are explainable exceptions, where surface water has had opportunity to invade certain aquifers. Ion ratio maps show the effect of time and rock compositions upon the relative kind and amount of dissolved solids in the water, due to reactions with minerals and organic material in the rocks.

REVIEW OF ARTIFICIAL GROUNDWATER RECHARGE IN THE COASTAL PLAIN OF ISRAEL

SUMMARY The Coastal Plain aquifer of Israel, of Plio-Pleistocene Age, stretches from Binyamina in the North to the Gaza Strip in the South-a distance of about 112 km and has an average width of about 15 Km. The allowed withdrawal is estimated at about 200 MCM/year. As a result of an average yearly withdrawal of 426 MCM/year during the last 10 years the water levels dropped to a dangerously low position (-2)-(-4) m below sea level at distances of 3–5 Km from the coast, causing sea water intrusion which, in Tel Aviv and Emek Hefer, endangered water supply wells. As a counter-measure, artificial groundwater recharge through wells was practiced in Emek Hefer since 1959. Recharge was practiced in 7 wells at a rate of 6 MCM/year, the water coming from adjacent Cretaceous limestone aquifers. In Tel Aviv a fresh water barrier was established in 1964 by injecting Lake Kinereth water into 17 wells during winter at a rate of 6 MCM/winter. In the rest of the Coastal Plain water was injected to the aquifer through abo...

Nature et origine des eaux de Barbotan, Dax et Cauterets (Aquitaine)

Abstract Due to numerous data from petroleum exploration in Aquitaine, new hypotheses are advanced concerning certain thermal springs: Barbotan seems to issue from an aquifer in sands below molassic deposits; Dax flows from an upper Cretaceous aquifer; the Cauterets waters are iodine-rich as are the granites from which they flow.