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1.
The sea level rise has its own-bearing on the coastal recession and hydro-environmental degradation of the River Nile Delta.
Attempts are made here to use remote sensing to detect the coastal recession in some selected parts and delineating the chemistry
of groundwater aquifers and surface water, which lie along south-mid-northern and coastal zone of the Nile Delta. Eight water
samples from groundwater monitoring wells and 13 water samples from surface water were collected and analyzed for various
hydrochemical parameters. The groundwater samples are classified into five hydrochemical facies on Hill-Piper trilinear diagram
based on the dominance of different cations and anions: facies 1: Ca–Mg–Na–HCO3–Cl–SO4 type I; facies 2: Na–Cl–HCO3 type II; facies 3: Na–Ca–Mg–Cl type III, facies 4: Ca–Na–Mg–Cl–HCO3 type IV and facies 5: Na–Mg–Cl type V. The hydrochemical facies showed that the majority of samples were enriched in sodium,
bicarbonate and chloride types and, which reflected that the sea water and tidal channel play a major role in controlling
the groundwater chemical composition in the Quaternary shallow aquifers, with a severe degradation going north of Nile Delta.
Also, the relationship between the dissolved chloride (Cl, mmol/l), as a variable, and other major ion combinations (in mmol/l)
were considered as another criterion for chemical classification system. The low and medium chloride groundwater occurs in
southern and mid Nile Delta (Classes A and B), whereas the high and very high chloride (classes D and C) almost covers the
northern parts of the Nile Delta indicating the severe effect of sea water intrusion. Other facets of hydro-environmental
degradation are reflected through monitoring the soil degradation process within the last two decades in the northern part
of Nile Delta. Land degradation was assessed by adopting new approach through the integration of GLASOD/FAO approach and Remote
Sensing/GIS techniques. The main types of human induced soil degradation observed in the studied area are salinity, alkalinity
(sodicity), compaction and water logging. On the other hand, water erosion because of sea rise is assessed. Multi-dates satellite
data from Landsat TM and ETM+ images dated 1983 and 2003 were used to detect the changes of shoreline during the last two
decades. The obtained results showed that, the eroded areas were determined as 568.20 acre; meanwhile the accreted areas were
detected as 494.61 acre during the 20-year period. 相似文献
2.
The total amount of groundwater resources in the middle and upper Odra River basin is 5200×103 m3/d, or about 7.7% of the disposable groundwater resources of Poland. The average modulus of groundwater resources is about
1.4 L/s/km2. Of the 180 'Major Groundwater Basins' (MGWB) in Poland, 43 are partly or totally located within the study area. The MGWB
in southwestern Poland have an average modulus of groundwater resources about 2.28 L/s/km2 and thus have abundant water resources in comparison to MGWB from other parts of the country.
Several types of mineral waters occur in the middle and upper Odra River basin. These waters are concentrated especially in
the Sudety Mountains. Carbon-dioxide waters, with yields of 414 m3/h, are the most widespread of Sudetic mineral waters.
The fresh waters of the crystalline basement have a low mineralization, commonly less than 100 mg/L; they are a HCO3–Ca–Mg or SO4–Ca–Mg type of water. Various hydrochemical compositions characterize the groundwater in sedimentary rocks. The shallow aquifers
are under risk of atmospheric pollution and anthropogenic effects. To prevent the degradation of groundwater resources in
the middle and upper Odra River basin, Critical Protection Areas have been designated within the MGWB.
Received, January 1995 Revised, May 1996, August 1997 Accepted, August 1997 相似文献
3.
Patterns in groundwater chemistry resulting from groundwater flow 总被引:18,自引:7,他引:11
Pieter J. Stuyfzand 《Hydrogeology Journal》1999,7(1):15-27
Groundwater flow influences hydrochemical patterns because flow reduces mixing by diffusion, carries the chemical imprints
of biological and anthropogenic changes in the recharge area, and leaches the aquifer system. Global patterns are mainly dictated
by differences in the flux of meteoric water passing through the subsoil. Within individual hydrosomes (water bodies with
a specific origin), the following prograde evolution lines (facies sequence) normally develop in the direction of groundwater
flow: from strong to no fluctuations in water quality, from polluted to unpolluted, from acidic to basic, from oxic to anoxic–methanogenic,
from no to significant base exchange, and from fresh to brackish. This is demonstrated for fresh coastal-dune groundwater
in the Netherlands. In this hydrosome, the leaching of calcium carbonate as much as 15 m and of adsorbed marine cations (Na+, K+, and Mg2+) as much as 2500 m in the flow direction is shown to correspond with about 5000 yr of flushing since the beach barrier with
dunes developed. Recharge focus areas in the dunes are evidenced by groundwater displaying a lower prograde quality evolution
than the surrounding dune groundwater. Artificially recharged Rhine River water in the dunes provides distinct hydrochemical
patterns, which display groundwater flow, mixing, and groundwater ages.
Received, May 1998 · Revised, August 1998 · Accepted, October 1998 相似文献
4.
A proposed new diagram for geochemical classification of natural waters and interpretation of chemical data 总被引:14,自引:1,他引:13
D. K. Chadha 《Hydrogeology Journal》1999,7(5):431-439
A new hydrochemical diagram is proposed for classification of natural waters and identification of hydrochemical processes.
The proposed diagram differs from the Piper and expanded Durov diagrams in that the two equilateral triangles are omitted,
and the shape of the main study field is different. In addition, the proposed diagram can be constructed on most spreadsheet
software packages. The proposed diagram is constructed by plotting the difference in milliequivalent percentage between alkaline
earths and alkali metals, expressed as percentage reacting values, on the X axis; and the difference in milliequivalent percentage
between weak acidic anions and strong acidic anions, also expressed as percentage reacting values, on the Y axis. The milliequivalent
percentage differences from the X and Y co-ordinates are extended further into the main study sub-fields of the proposed diagram,
which defines the overall character of water. Examples of hydrochemical analyses of groundwater are given from Karnataka,
India, for each of the three types of diagrams, illustrating the applicability of the proposed diagram in four case histories
having different hydrogeochemical aspects. A comparison indicates that the proposed new diagram satisfies the basic requirement
for a suitable classification of natural waters, and it also can be effectively used for studies of hydrochemical processes.
Received, April 1998 / Revised, February 1999 / Accepted, April 1999 相似文献
5.
The hydrochemical characteristics and quality of groundwater in Lokoja basement area have been evaluated based on different indices for assessing groundwater for drinking and irrigation purposes. Twenty groundwater samples were collected and analyzed for physicochemical parameters, major ions and heavy metals. The results revealed that the groundwater is slightly alkaline, with little variations in chemical composition. For example, electrical conductivity (EC) ranges from 242μS/cm to 1835μS/cm. The abundance of the major ions is in the order of Ca2+ >Na+>Mg2+>K+> Fe2+/3+ = HCO3 >Cl? >NO3 >SO4 >PO4. Based on the hydrochemical data, four hydrochemical facies were identified namely, Ca-Mg-HCO3, Na-K-HCO3, Na-K-Cl-SO4 and Ca-Mg-Cl-SO4 and these facies depict groundwater recharge zone, transition flow zone, deep flow zone and mixed water zone respectively. Groundwater from the area is unsuitable for drinking and domestic purposes as some of the ions and heavy metals of health concerns are well above the stipulated guideline values. Irrigation water quality indicators (salinity, Na % and Mg %), reveal that the groundwater is unsuitable for irrigation purposes. Interpreted statistical analysis reveals that the groundwater chemical compositions are controlled predominantly by weathering of litho units of the basement rocks and by drainage from domestic wastes. 相似文献
6.
对内蒙古杭锦旗气田区浅层地下水运用Piper三线图、Gibbs图、氯碱指数图等方法进行水化学特征及其形成作用分析研究,结果表明:杭锦旗气田区浅层地下水具有较高的矿化度,偏碱性,硬度较大,枯水期TDS浓度和总硬度高于丰水期;研究区浅层地下水化学组分在小范围内具有一定的空间变异性,地下水阳离子以Na+、Ca2+为主,阴离子以HCO3-为主,水化学类型主要有HCO3 Ca型、HCO3 Na型和SO4·Cl Na型;研究区浅层地下水化学组分来源于碳酸盐矿物、硅铝酸盐矿物和蒸发岩的风化溶解,且丰水期和枯水期水化学组分有微弱变化,地下水化学特征的形成以岩石风化溶解作用为主。 相似文献
7.
衡水地区多年超采深层地下水,形成了以衡水市区为中心的区域地下水降落漏斗,改变了初始的水动力场和水化学场。运用聚类分析、Piper三线图、Gibbs图、氯碱指数、离子相关关系方法分析了该地区历史时期和现阶段深层地下水的水文地球化学特征及其演化规律,探讨了水化学组分的来源及形成机制。结果表明:该地区深层地下水水化学演化受到了较大的人类活动影响,根据Q型聚类分析将研究区划分为补给、径流、排泄3个水化学分区。20世纪70年代到现阶段,随降落漏斗产生发展,研究区形成了新的局部补径排关系,加强了地下水对围岩的溶滤作用,导致研究区水化学场发生了变化,径流区地下水水化学类型由Cl·HCO3-Na、HCO3·Cl-Na和SO4·Cl-Na转化为SO4·Cl-Na和Cl·SO4-Na,排泄区地下水水化学类型由Cl·HCO3-Na和Cl-Na转化为Cl-Na。Gibbs图和离子关系显示,研究区现阶段深层地下水在降落漏斗影响下,水化学组分主要受岩石风化、阳离子交替吸附和脱碳酸作用控制。 相似文献
8.
Usama Abu Risha Sayed Mosaad El Sayed El Abd Abdel Mohsen Hasanein 《Arabian Journal of Geosciences》2017,10(21):461
The groundwater extracted from the unconfined Quaternary aquifer is the main source of water supply in El-Tur area. The area is bounded from the east by the elevated basement complex of Southern Sinai and from the west by El-Qabaliyat Ridge. The wadis dissecting these highlands form effective watersheds of the Quaternary aquifer. These wadis form areas of focused recharge. Recharge also occurs directly via the Quaternary sediments covering El-Qaa Plain. Subsurface lateral groundwater flow from the fractured basement contributes significant recharge to the aquifer as well. The aquifer sediment facies affect the type and quality of groundwater. In the eastern part where the aquifer is composed mainly of gravel and coarse sand with fragments of weathered basement, the Na-Cl-SO4 water dominates. In the west where the facies change is rapid and complex, many water types arise. The base exchange index (BEX) is positive in this part reflecting the role of clay minerals in changing the water types via cation exchange. In the east where clays are insignificant in the aquifer, the BEX is negative. In the western part next to El-Qabaliyat Ridge, the wells discharging from the calcareous sand zone have low groundwater salinities compared to the wells discharging from the alluvium. In general, the groundwater salinity increases in the direction of groundwater flow from the northeast to the southwest which reflects the dissolution of aquifer sediments. The concentration relationships between the major ions on one hand and chloride on the other reflect the dissolution of calcium carbonates, precipitation of K- and Mg-bearing minerals, and cation exchange of Ca for Na on clay minerals. The hydrochemical models support these reactions. In addition, they show that the effect of evaporation on the recharge water in the western catchment is about four times its effect on the eastern recharge water which reflects the rapid recharge through the wadis draining the fractured basement. Moreover, the contribution from the eastern catchment in sample No. 23 is more than four-folds the contribution from the western recharge area. The stable isotopes (2H and 18O) show that the Quaternary aquifer is recharging from recent rainfall. However, upward leakage of Paleogene groundwater (depleted in 18O) also occurs. The groundwater level map shows strong overpumping impact especially in the areas close to El-Tur city. 相似文献
9.
广西北海市地下水系统水化学特征的分析 总被引:5,自引:2,他引:3
对广西北海市近20年的地下水水质监测资料和2002-2003年野外实地取样的测试资料进行分析,并采用Piper图和Q型群分析进行水化学分类,结果表明该地区北部地下水以Ca·Na-HCO3型为主,水化学特征显示地下水化学成分受降雨入渗和溶滤的影响,而南部地下水以Na-Cl或Na·Ca-Cl型为主。北海市天然条件下地下水的矿化度低,pH值低,呈偏酸性。低矿化度的雨水、可溶盐含量极低的含水介质、迅速的水循环以及长期的淋滤作用,导致了北海地区地下水低矿化度的特点。 相似文献
10.
Groundwater in alluvial aquifers of the Wakatipu and Wanaka basins, Central Otago, New Zealand, has a composition expressed
in equivalent units of Ca2+≫Mg2+≅Na+>K+ for cations, and HCO3
–≫SO4
2->NO3
–≅Cl– for anions. Ca2+ and HCO3
– occur on a 1 : 1 equivalent basis and account for >80% of the ions in solution. However, some groundwater has increased proportions
of Na+ and SO4
2-, reflecting a different source for this water.
The rock material of the alluvial aquifers of both basins is derived from the erosion and weathering of metamorphic Otago
Schist (grey and green schists). Calcite is an accessory mineral in both the grey and green schists at <5% of the rock. Geological
mapping of both basins indicates that dissolution of calcite from the schist is the only likely mechanism for producing groundwater
with such a constant composition dominated by Ca2+ and HCO3
– on a 1 : 1 equivalent basis. Groundwater with higher proportions of Na+ and SO4
2- occurs near areas where the schist crops out at the surface, and this groundwater represents deeper and possibly older water
derived from basement fluids. Anomalously high K+ in the Wakatipu basin and high NO3
– concentrations in the Wanaka basin cannot be accounted for by interaction with basement lithologies, and these concentrations
probably represent the influence of anthropogenic sources on groundwater composition.
Received, June 1996 Revised, March 1997, July 1997 Accepted, July 1997 相似文献
11.
Hydrochemical evolution and water quality along the groundwater flow path in the Sandıklı plain, Afyon, Turkey 总被引:1,自引:0,他引:1
M. Afşin 《Environmental Geology》1997,31(3-4):221-230
An unconfined aquifer system suggests an open system in the study area. Hydrochemical evolution is related to the flow path
of groundwater. The groundwaters are divided into two hydrochemical facies in the study area, 1) Ca–Mg–HCO3 and 2) Ca–Mg–SO4HCO3. Facies 1 has shallow (young) waters which dominate in recharge areas during rapid flow conditions, whereas facies 2 may
show shallow and mixed waters which dominate intermediate or discharge areas during low flow conditions. Ionic concentrations,
TDS, EC and water quality are related to groundwater residence time and groundwater types. The groundwaters in the plain are
chemically potable and suitable for both domestic and agricultural purposes.
Received: 20 May 1996 · Accepted: 30 July 1996 相似文献
12.
鄂尔多斯白垩系地下水盆地地下水水化学类型的分布规律 总被引:10,自引:0,他引:10
在对鄂尔多斯白垩系地下水盆地1 125件地下水化学样品进行分析的基础上,总结出研究区不同循环深度地下水化学类型的分布规律。总体上,盆地北区大致以安边—四十里梁—东胜梁地表分水岭为界,东侧地区的浅层、中层和深层地下水化学类型均以HCO3型水为主,地下水水平分带不典型;而分水岭以西的摩林河-盐海子地下水系统和都思兔河—盐池地下水系统中,包括浅层、中层和深层在内的各层地下水表现为沿地下水流向,向盆地北、西侧边界,水化学类型具有明显的水平分带规律。而盆地南区地下水分层径流明显,水化学类型复杂,总体上存在一个以定边—环县—合水—华池—吴旗—定边为中心的北部由北向南、东部由东向西、南部由西南向东北的水平分带。 相似文献
13.
Groundwater processes and sedimentary uranium deposits 总被引:8,自引:0,他引:8
Hydrologic processes are fundamental in the emplacement of all three major categories of sedimentary uranium deposits: syngenetic,
syndiagenetic, and epigenetic. In each case, the basic sedimentary uranium-enrichment cycle involves: (1) leaching or erosion
of uranium from a low-grade provenance; (2) transport of uranium by surface or groundwater flow; and (3) concentration of
uranium by mechanical, geochemical, or physiochemical processes. Although surface flow was responsible for lower Precambrian
uranium deposits, groundwater was the primary agent in upper Precambrian and Phanerozoic sedimentary uranium emplacement.
Meteoric or more deeply derived groundwater flow transported uranium in solution through transmissive facies, generally sands
and gravels, until it was precipitated under reducing conditions. Syndiagenetic uranium deposits are typically concentrated
in reducing lacustrine and swamp environments, whereas epigenetic deposits accumulated along mineralization fronts or tabular
boundaries.
The role of groundwater is particularly well illustrated in the bedload fluvial systems of the South Texas uranium province.
Upward migration of deep, reducing brines conditioned the host rock before oxidizing meteoric flow concentrated uranium and
other secondary minerals. Interactions between uranium-transporting groundwater and the transmissive aquifer facies are also
reflected in the uranium mineralization fronts in the lower Tertiary basins of Wyoming. Similar relationships are observed
in the tabular uranium deposits of the Colorado Plateau.
Received, May 1998 · Revised, July 1998 · Accepted, September 1998 相似文献
14.
Assessment of change in major ion chemistry of groundwater, manifested by hydrochemical facies, is a necessity for sustainable use of the groundwater resources. In this perspective, this article estimates spatial and temporal hydrochemical facies variation in the study area using an integrated approach. The geochemical, isotopic and sedimentary data from the North West Delhi has been used to achieve the objective of the study. It is seen that the spatial groundwater facies variation in the study area correlates with the change in geomorphologic units. Distinct hydrochemical facies for younger and older alluvial plains has been observed. It is seen that geomorphic features such as palaeochannels also influence the groundwater quality of the study area. Further, the temporal hydrochemical facies variations indicate that with time, anthropogenic factors have also impacted the evolution of facies in the study area . 相似文献
15.
Hydrochemical system analysis of public supply well fields, to reveal water-quality patterns and define groundwater bodies: The Netherlands 总被引:1,自引:1,他引:0
Hydrochemical system analysis (HCSA) is used to better understand the individual state of and spatial patterns in groundwater quality, by addressing the spatial distribution of groundwater bodies with specific origins (hydrosomes) and characteristic hydrochemical zones within each hydrosome (facies). The origin is determined by environmental tracers or geomorphological and potentiometric maps, the facies by combining age, redox and alkalinity indices. The HCSA method is applied to all 206 active public supply well fields (PSWFs) in The Netherlands, resulting in the distinction of nine hydrosomes and eleven facies parameters—age (young, intermediate, old), redox ((sub)oxic, anoxic, deep anoxic, mixed) and alkalinity (very low, low, intermediate and high). The resulting classification of PSWFs provides a means to (1) predict their vulnerability; (2) optimize groundwater-quality monitoring programs; and (3) better delineate groundwater bodies, by considering groundwater origin and flow. The HCSA translates complex hydrochemical patterns into easily interpretable maps by showing PSWFs, groundwater bodies and hydrochemical facies. Such maps facilitate communication between researchers, water resources managers and policy makers and can help to solve complex groundwater resources management problems at different scales, ranging from a single well(field) or region to the national or European scale. 相似文献
16.
17.
Understanding factors influencing groundwater chemistry in regional groundwater basins is important to prevent groundwater pollution especially in arid areas where rainfall is low and water resources are limited. The present study assesses such factors in the regional, geologically diverse, groundwater basin of Wadi Umairy in Oman. The basin is composed of five different lithostratigraphic units with different hydraulic properties. Water samples (41) have been collected from the different units and analyzed for the major ions. Factor analysis and conventional hydrochemical methods were used to define the factors that have significant impact on the aquifer's hydrochemistry. It was found that evaporation and mineral weathering/dissolution are the main factors defining the groundwater chemistry along the flow path from recharge to discharge zones, whereas anthropogenic activities and alkalinity are found to be of lesser effect, and the latter prevails when the rocks are predominantly monomineralic. It was concluded that in regional groundwater basins, recharge/discharge relations together with the flow scale control the hydrochemistry irrespective of lithological variation in the basin. 相似文献
18.
Analysis of groundwater chemistry can yield important insights about subsurface conditions, and provide an alternative and complementary method for characterizing basin hydrogeology, especially in areas where hydraulic data are limited. More specifically, hydrochemical facies have been used for decades to help understand basin flow and transport, and a set of facies were developed for the Roswell Artesian Basin (RAB) in a semi-arid part of New Mexico, USA. The RAB is an important agricultural water source, and is an excellent example of a rechargeable artesian system. However, substantial uncertainties about the RAB hydrogeology and groundwater chemistry exist. The RAB was a great opportunity to explore hydrochemcial facies definition. A set of facies, derived from fingerprint diagrams (graphical approach), existed as a basis for testing and for comparison to principal components, factor analysis, and cluster analyses (statistical approaches). Geochemical data from over 300 RAB wells in the central basin were examined. The statistical testing of fingerprint-diagram-based facies was useful in terms of quantitatively evaluating differences between facies, and for understanding potential controls on basin groundwater chemistry. This study suggests the presence of three hydrochemical facies in the shallower part of the RAB (mostly unconfined conditions) and three in the deeper artesian system of the RAB. These facies reflect significant spatial differences in chemistry in the basin that are associated with specific stratigraphic intervals as well as structural features. Substantial chemical variability across faults and within fault blocks was also observed. 相似文献
19.
Application of remote-sensing data to groundwater exploration: A case study of the Cross River State, southeastern Nigeria 总被引:12,自引:2,他引:10
The Cross River State, Nigeria, is underlain by the Precambrian-age crystalline basement complex and by rocks of Cretaceous
to Tertiary age. The exploration for groundwater in this area requires a systematic technique in order to obtain optimum results,
but the non-availability of funds and facilities has made it extremely difficult to carry out site investigations prior to
the drilling of water wells. Therefore, the failure rate is as high as 80%. In order to delineate areas that are expected
to be suitable for future groundwater development, black and white radar imagery and aerial photographs were used to define
some hydrological and hydrogeological features in parts of the study area. Lineament and drainage patterns were analysed using
length density and frequency. Lineament-length density ranges from 0.04–1.52; lineament frequency is 0.11–5.09; drainage-length
density is 0.17–0.94, and the drainage frequency is 0.16–1.53. These range of values reflect the differences in the probability
of groundwater potentials. Results were then used to delineate areas of high, medium, and low groundwater potential. Study
results also indicate that correlations exist between lineament and drainage patterns, lithology, water temperature, water
conductivity, well yield, transmissivity, longitudinal conductance, and the occurrence of groundwater.
Received, August 1994 · Revised, March 1996, June 1996 · Accepted, October 1996 相似文献
20.
Tunisian Chott’s region is one of the most productive artesian basins in Tunisia. It is located in the southwestern part of
the country, and its groundwater resources are developed for water supply and irrigation. The chemical composition of the
water is strongly influenced by the interaction with the basinal sediments and by hydrologic characteristics such as the flow
pattern and time of residence. The system is composed of an upper unconfined “Plio-Quaternary” aquifer with a varying thickness
of 20–200 m, an intermediate confined/unconfined “Complex Terminal” aquifer about 100 m in thickness and a deeper “Continental
Intercalaire” aquifer about 150 m in thickness separated by thick clay and marl layers. The dissolution of evaporites and
carbonates explains part of the contained Na+, Ca2+, Mg2+, K+, SO42− and Cl-, but other processes, such carbonate precipitation, also contributes to the water composition. The stable isotope composition
of waters establishes that the deep groundwater (depleted as compared to present corresponding local rainfall) is ancient
water recharged probably during the late Pleistocene and the early Holocene periods. The relatively recent water in the Plio-Quaternary
aquifer is composed of mixed waters resulting presumably from upward leakage from the deeper groundwater. 相似文献