共查询到20条相似文献，搜索用时 578 毫秒
1.
Kuroda Keisuke Hayashi Takeshi Do An Thuan Canh Vu Duc Nga Tran Thi Viet Funabiki Ayako Takizawa Satoshi 《Hydrogeology Journal》2017,25(3):727-742
Over-exploited groundwater is expected to remain the predominant source of domestic water in suburban areas of Hanoi, Vietnam. In order to evaluate the effect on groundwater recharge, of decreasing surface-water bodies and land-use change caused by urbanization, the relevant groundwater systems and recharge pathways must be characterized in detail. To this end, water levels and water quality were monitored for 3 years regarding groundwater and adjacent surface-water bodies, at two typical suburban sites in Hanoi. Stable isotope (δ18O, δD of water) analysis and hydrochemical analysis showed that the water from both aquifers and aquitards, including the groundwater obtained from both the monitoring wells and the neighboring household tubewells, was largely derived from evaporation-affected surface-water bodies (e.g., ponds, irrigated farmlands) rather than from rivers. The water-level monitoring results suggested distinct local-scale flow systems for both a Holocene unconfined aquifer (HUA) and Pleistocene confined aquifer (PCA). That is, in the case of the HUA, lateral recharge through the aquifer from neighboring ponds and/or irrigated farmlands appeared to be dominant, rather than recharge by vertical rainwater infiltration. In the case of the PCA, recharge by the above-lying HUA, through areas where the aquitard separating the two aquifers was relatively thin or nonexistent, was suggested. As the decrease in the local surface-water bodies will likely reduce the groundwater recharge, maintaining and enhancing this recharge (through preservation of the surface-water bodies) is considered as essential for the sustainable use of groundwater in the area.
相似文献2.
Jonathan Levy Gordon Chesters Daniel P. Gustafson Harry W. Read 《Hydrogeology Journal》1998,6(4):483-499
A field study from October 1989 through July 1992, conducted on a 4.1-km2 area in south-central Wisconsin, USA, examined the distributions of atrazine and its chlorinated metabolites in groundwater
and related those distributions to the groundwater flow system. MODFLOW and PATH3D were used to assess bedrock-aquifer susceptibility
to contamination. Estimated travel time from water table to bedrock surface ranges from <0.25 to >512 yr. Spatial distribution
of the estimates demonstrates that increased travel time to bedrock can result from the presence of shallow surface-water
bodies, greater depths to bedrock, and smaller hydraulic conductivities. Estimated travel times to local domestic wells are
inversely related to atrazine and desethylated atrazine concentrations observed in water from those wells.
The potential impact of long-term atrazine use on aquifer water quality was investigated using MT3D in two best-case scenarios.
Uncertainties associated with predicted atrazine concentrations at various depths and times were estimated. For shallow groundwater,
widespread violations of Wisconsin's current preventive action limit were predicted, but with large uncertainty stemming from
uncertain estimates of input parameter values. The simulations indicate, however, that moderate inputs at the water table
are very unlikely to produce violations of Wisconsin's standards deeper in the aquifer.
Received, October 1997 Revised, July 1998 Accepted, July 1998 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.
松嫩平原地下水流动模式的环境同位素标记 总被引：2，自引：0，他引：2
采用同位素水文学方法并结合传统水文地质方法,识别松嫩平原地下水流动模式。氢氧稳定同位素和地下水年龄分布表明该区地下水流动系统流动模式呈现出局部流、中间流和区域流系统。地下水中氚分布深度指示局部水流系统为现代水循环系统,以垂向运动为主要特征,循环深度一般小于50 m,山前区可达100m以下;区域流系统存在于深部承压含水层,以侧向水平径流为主要运动特征。松辽边界附近的环境同位素特征存在明显的差别,指示天然状态下可视为零通量边界。同位素示踪剂也反映出嫩江和地下水的相互作用关系,在齐齐哈尔以北,江水补给地下水;在齐齐哈尔以南,地下水向嫩江排泄。 相似文献
5.
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
6.
Contributions of groundwater conditions to soil and water salinization 总被引：23，自引：2，他引：21
Salinization is the process whereby the concentration of dissolved salts in water and soil is increased due to natural or
human-induced processes. Water is lost through one or any combination of four main mechanisms: evaporation, evapotranspiration,
hydrolysis, and leakage between aquifers. Salinity increases from catchment divides to the valley floors and in the direction
of groundwater flow. Salinization is explained by two main chemical models developed by the authors: weathering and deposition.
These models are in agreement with the weathering and depositional geological processes that have formed soils and overburden
in the catchments. Five soil-change processes in arid and semi-arid climates are associated with waterlogging and water. In
all represented cases, groundwater is the main geological agent for transmitting, accumulating, and discharging salt. At a
small catchment scale in South and Western Australia, water is lost through evapotranspiration and hydrolysis. Saline groundwater
flows along the beds of the streams and is accumulated in paleochannels, which act as a salt repository, and finally discharges
in lakes, where most of the saline groundwater is concentrated. In the hummocky terrains of the Northern Great Plains Region,
Canada and USA, the localized recharge and discharge scenarios cause salinization to occur mainly in depressions, in conjunction
with the formation of saline soils and seepages. On a regional scale within closed basins, this process can create playas
or saline lakes. In the continental aquifers of the rift basins of Sudan, salinity increases along the groundwater flow path
and forms a saline zone at the distal end. The saline zone in each rift forms a closed ridge, which coincides with the closed
trough of the groundwater-level map. The saline body or bodies were formed by evaporation coupled with alkaline-earth carbonate
precipitation and dissolution of capillary salts.
Received, May 1998 · Revised, July 1998 · Accepted, September 1998 相似文献
7.
Hans G. Machel 《Hydrogeology Journal》1999,7(1):94-107
This article provides a critical synopsis of the effects of groundwater flow on mineral diagenesis. Emphasis is placed on
those aspects and processes that change porosity and permeability in carbonate aquifers, because they are of particular importance
to human societies as sources of supplies of water for human consumption (drinking, irrigation) and of crude oil and natural
gas.
Diagenetic settings in carbonates as well as clastics are generally ill defined. This paper proposes a new comprehensive classification
of diagenetic settings into near-surface, shallow-, intermediate-, and deep-burial diagenetic settings; hydrocarbon-contaminated
plumes; and fractures. These settings are defined on the basis of mineralogy, petroleum, hydrogeochemistry, and hydrogeology.
This classification is applicable to all sedimentary basins.
Diagenesis is governed by various intrinsic and extrinsic factors that include thermodynamic and kinetic constraints, as well
as microstructural factors that may override the others. These factors govern diagenetic processes, such as dissolution, compaction,
recrystallization, replacement, and sulfate–hydrocarbon redox-reactions. Processes such as cementation, dissolution, and dolomitization
require significant flow of groundwater driven by an externally imposed hydraulic gradient. Other processes, such as stylolitization
and thermochemical sulfate reduction, commonly take place without significant groundwater flow in hydrologically nearly or
completely stagnant systems that are geochemically "closed."
Two major effects of groundwater flow on mineral diagenesis are enhancement and reduction of porosity and permeability, although
groundwater flow can also leave these rock properties essentially unchanged. In extreme cases, an aquifer or hydrocarbon reservoir
rock can have highly enhanced porosity and permeability due to extensive mineral dissolution, or it can be plugged up due
to extensive mineral precipitation.
Received, April 1998 · Revised, July 1998 · Accepted, September 1998 相似文献
8.
Marios Sophocleous 《Hydrogeology Journal》2002,10(1):52-67
The interactions between groundwater and surface water are complex. To understand these interactions in relation to climate,
landform, geology, and biotic factors, a sound hydrogeoecological framework is needed. All these aspects are synthesized and
exemplified in this overview. In addition, the mechanisms of interactions between groundwater and surface water (GW–SW) as
they affect recharge–discharge processes are comprehensively outlined, and the ecological significance and the human impacts
of such interactions are emphasized. Surface-water and groundwater ecosystems are viewed as linked components of a hydrologic
continuum leading to related sustainability issues. This overview concludes with a discussion of research needs and challenges
facing this evolving field. The biogeochemical processes within the upper few centimeters of sediments beneath nearly all
surface-water bodies (hyporheic zone) have a profound effect on the chemistry of the water interchange, and here is where most of the recent research has been
focusing. However, to advance conceptual and other modeling of GW–SW systems, a broader perspective of such interactions across
and between surface-water bodies is needed, including multidimensional analyses, interface hydraulic characterization and
spatial variability, site-to-region regionalization approaches, as well as cross-disciplinary collaborations.
Electronic Publication 相似文献
9.
Gennaro A. Stefania Marco Rotiroti Letizia Fumagalli Fulvio Simonetto Pietro Capodaglio Chiara Zanotti Tullia Bonomi 《Hydrogeology Journal》2018,26(1):147-162
A groundwater flow model of the Alpine valley aquifer in the Aosta Plain (NW Italy) showed that well pumping can induce river streamflow depletions as a function of well location. Analysis of the water budget showed that ～80% of the water pumped during 2 years by a selected well in the downstream area comes from the baseflow of the main river discharge. Alluvial aquifers hosted in Alpine valleys fall within a particular hydrogeological context where groundwater/surface-water relationships change from upstream to downstream as well as seasonally. A transient groundwater model using MODFLOW2005 and the Streamflow-Routing (SFR2) Package is here presented, aimed at investigating water exchanges between the main regional river (Dora Baltea River, a left-hand tributary of the Po River), its tributaries and the underlying shallow aquifer, which is affected by seasonal oscillations. The three-dimensional distribution of the hydraulic conductivity of the aquifer was obtained by means of a specific coding system within the database TANGRAM. Both head and flux targets were used to perform the model calibration using PEST. Results showed that the fluctuations of the water table play an important role in groundwater/surface-water interconnections. In upstream areas, groundwater is recharged by water leaking through the riverbed and the well abstraction component of the water budget changes as a function of the hydraulic conditions of the aquifer. In downstream areas, groundwater is drained by the river and most of the water pumped by wells comes from the base flow component of the river discharge. 相似文献
10.
Groundwater/surface-water interactions on deeply weathered surfaces of low relief: evidence from Lakes Victoria and Kyoga, Uganda 总被引：1，自引：1，他引：0
Michael Owor Richard Taylor Christine Mukwaya Callist Tindimugaya 《Hydrogeology Journal》2011,19(7):1403-1420
Little is known of the interactions between groundwater and surface water on deeply weathered landscapes of low relief in the Great Lakes Region of Africa (GLRA). The role of groundwater in sustaining surface-water levels during periods of absent rainfall is disputed and groundwater is commonly excluded from estimations of surface-water balances. Triangulated piezometers installed beside lake gauging stations on Lake Victoria and Lake Kyoga in Uganda provide the first evidence of the dynamic interaction between groundwater and surface water in the GLRA. Stable isotope ratios (2H:1H, 18O:16O) support piezometric evidence that groundwater primarily discharges to lakes but show further that mixing of groundwater and lake water has occurred at one site on Lake Victoria (Jinja). Layered-aquifer heterogeneity, wherein fluvial-lacustrine sands overlie saprolite, gives rise to both rapid and slow groundwater fluxes to lakes which is evident from the recession of borehole hydrographs following recharge events. Darcy throughflow calculations suggest that direct contributions from groundwater to Lake Victoria comprise <1% of the total inflows to the lake. Groundwater/surface-water interactions are strongly influenced by changing drainage base (lake) levels that are controlled, in part, by regional climate variability and dam releases from Lake Victoria (Jinja). 相似文献
11.
Groundwater flow and solute transport at the Mourquong saline-water disposal basin, Murray Basin, southeastern Australia 总被引：5，自引：0，他引：5
Craig T. Simmons Kumar A. Narayan Juliette A. Woods Andrew L. Herczeg 《Hydrogeology Journal》2002,10(2):278-295
Saline groundwater and drainage effluent from irrigation are commonly stored in some 200 natural and artificial saline-water
disposal basins throughout the Murray-Darling Basin of Australia. Their impact on underlying aquifers and the River Murray,
one of Australia's major water supplies, is of serious concern. In one such scheme, saline groundwater is pumped into Lake
Mourquong, a natural groundwater discharge complex. The disposal basin is hydrodynamically restricted by low-permeability
lacustrine clays, but there are vulnerable areas in the southeast where the clay is apparently missing. The extent of vertical
and lateral leakage of basin brines and the processes controlling their migration are examined using (1) analyses of chloride
and stable isotopes of water (2H/1H and 18O/16O) to infer mixing between regional groundwater and lake water, and (2) the variable-density groundwater flow and solute-transport
code SUTRA. Hydrochemical results indicate that evaporated disposal water has moved at least 100 m in an easterly direction
and that there is negligible movement of brines in a southerly direction towards the River Murray. The model is used to consider
various management scenarios. Salt-load movement to the River Murray was highest in a "worst-case" scenario with irrigation
employed between the basin and the River Murray. Present-day operating conditions lead to little, if any, direct movement
of brine from the basin into the river.
Electronic Publication 相似文献
12.
Geomorphic aspects of groundwater flow 总被引：3，自引：0，他引：3
Robert G. LaFleur 《Hydrogeology Journal》1999,7(1):78-93
The many roles that groundwater plays in landscape evolution are becoming more widely appreciated. In this overview, three
major categories of groundwater processes and resulting landforms are considered: (1) Dissolution creates various karst geometries,
mainly in carbonate rocks, in response to conditions of recharge, geologic setting, lithology, and groundwater circulation.
Denudation and cave formation rates can be estimated from kinetic and hydraulic parameters. (2) Groundwater weathering generates
regoliths of residual alteration products at weathering fronts, and subsequent exhumation exposes corestones, flared slopes,
balanced rocks, domed inselbergs, and etchplains of regional importance. Groundwater relocation of dissolved salts creates
duricrusts of various compositions, which become landforms. (3) Soil and rock erosion by groundwater processes include piping,
seepage erosion, and sapping, important agents in slope retreat and headward gully migration. Thresholds and limits are important
in many chemical and mechanical groundwater actions. A quantitative, morphometric approach to groundwater landforms and processes
is exemplified by selected studies in carbonate and clastic terrains of ancient and recent origins.
Received, May 1998 · Revised, September 1998 · Accepted, October 1998 相似文献
13.
Groundwater as a geologic agent: An overview of the causes, processes, and manifestations 总被引：29，自引：4，他引：25
József Tóth 《Hydrogeology Journal》1999,7(1):1-14
The objective of the present paper is to show that groundwater is a general geologic agent. This perception could not, and
did not, evolve until the system nature of basinal groundwater flow and its properties, geometries, and controlling factors
became recognized and understood through the 1960s and 1970s.
The two fundamental causes for groundwater's active role in nature are its ability to interact with the ambient environment
and the systematized spatial distribution of its flow. Interaction and flow occur simultaneously at all scales of space and
time, although at correspondingly varying rates and intensities. Thus, effects of groundwater flow are created from the land
surface to the greatest depths of the porous parts of the Earth's crust, and from a day's length through geologic times. Three
main types of interaction between groundwater and environment are identified in this paper, with several special processes
for each one, namely: (1) Chemical interaction, with processes of dissolution, hydration, hydrolysis, oxidation-reduction,
attack by acids, chemical precipitation, base exchange, sulfate reduction, concentration, and ultrafiltration or osmosis;
(2) Physical interaction, with processes of lubrication and pore-pressure modification; and (3) Kinetic interaction, with
the transport processes of water, aqueous and nonaqueous matter, and heat. Owing to the transporting ability and spatial patterns
of basinal flow, the effects of interaction are cumulative and distributed according to the geometries of the flow systems.
The number and diversity of natural phenomena that are generated by groundwater flow are almost unlimited, due to the fact
that the relatively few basic types are modified by some or all of the three components of the hydrogeologic environment:
topography, geology, and climate. The six basic groups into which manifestations of groundwater flow have been divided are:
(1) Hydrology and hydraulics; (2) Chemistry and mineralogy; (3) Vegetation; (4) Soil and rock mechanics; (5) Geomorphology;
and (6) Transport and accumulation. Based on such a diversity of effects and manifestations, it is concluded that groundwater
is a general geologic agent.
Received, December 1998 · Revised, January 1999 · Accepted, January 1999 相似文献
14.
Many groundwater systems consist of multi-scale aquifer units. The exchange processes and rates between these aquifer units are complex. In order to manage such complex systems, a subdivision into different catchments, sub-catchments or groundwater bodies as manageable units is required. The sustainable management of water resources requires a comprehensive view of water-quality and water-quantity aspects not only for water supply issues, but generally also for flood protection and riverine ecosystem functions. Such transformations require an improved understanding of recharge and exchange processes between different aquifer units as well as aquifer-surface water interaction-processes at different spatiotemporal scales. The main objective of this study is to illustrate concepts by defining the geometry and scales of different aquifer units within a sedimentary basin. The Laufen Basin in the Jura Mountains represents a sub-catchment of the River Birs (Switzerland). Its structure is characterized by a pronounced local relief and a series of aquifer units which are typical for many complex groundwater systems in front of mountain chains such as the alpine foreland and the Jura Mountains of Central Europe. A combination of different concepts is required to understand multi-scale flow systems and to describe the various hydrogeological processes. Three concepts are proposed for the Laufen Basin, including: (1) a regional flow-system analysis, based on the concept of hierarchical groundwater flow systems; (2) the river-corridor concept for understanding aquifer-surface water interaction processes; and (3) the calculation of the dynamic vulnerability index and the aquifer base gradient approach for karst flow and fractured flow systems. 相似文献
15.
《China Geology》2021,4(3):509-526
The fresh groundwater in the Loess Plateau serves as a major source of water required for the production and livelihood of local residents and is greatly significant for regional economic and social development and ecological protection. This paper analyzes the hydrogeological conditions and groundwater characteristics in the Loess Plateau, expatiates on the types and distribution characteristics of the fresh groundwater in the plateau, and analyzes the influencing factors and mechanisms in the formation of the fresh groundwater in the plateau as a priority. Based on this, it summarizes the impacts of human activities and climatic change on the regional fresh groundwater. The groundwater in Loess Plateau features uneven temporal-spatial distribution, with the distribution space of the fresh groundwater closely relating to precipitation. The groundwater shows a distinct zoning pattern of hydrochemical types. It is fresh water in shallow parts and is salt water in deep parts overall, while the fresh water of exploration value is distributed only in a small range. The storage space and migration pathways of fresh groundwater in the loess area feature dual voids, vertical multilayers, variable structure, poor renewability, complex recharge processes, and distinct spatial differences. In general, the total dissolved solids (TDS) of the same type of groundwater tends to gradually increase from recharge areas to discharge areas. Conditions favorable for the formation of fresh groundwater in loess tablelands include the low content of soluble salts in strata, weak evaporation, and special hydrodynamic conditions. Owing to climate change and human activities, the resource quantity of regional fresh water tends to decrease overall, and the groundwater dynamic field and the recharge-discharge relationships between groundwater and surface water have changed in local areas. Human activities have a small impact on the water quality but slightly affect the water quantity of the groundwater in loess.© 2021 China Geology Editorial Office. 相似文献
16.
Hydrogeological processes in seasonally frozen northern latitudes: understanding, gaps and challenges 总被引：2，自引：1，他引：1
A. M. Ireson G. van der Kamp G. Ferguson U. Nachshon H. S. Wheater 《Hydrogeology Journal》2013,21(1):53-66
The groundwater regime in seasonally frozen regions of the world exhibits distinct behavior. This paper presents an overview of flow and associated heat and solute transport processes in the subsurface, from the soil/vadose zone, through groundwater recharge to groundwater discharge processes in these areas. Theoretical developments, field studies and model development are considered. An illustrative conceptual model of the system is presented. From a groundwater perspective, the dominant effect is the extent of hydraulic isolation between the water above and that below the near-surface frozen zone. The spatial and temporal occurrences of this isolation are seasonally variable and may also be modified under a future changing climate. A good qualitative conceptual understanding of the system has been developed over numerous decades of study. A major gap is the inability to effectively monitor processes in the field, particularly unfrozen water content during freezing conditions. Modeling of field-scale behavior represents a major challenge, even while physically based models continue to improve. It is suggested that progress can be made by combining well-designed field experiments with modeling studies. A major motivation for improving quantification of these processes derives from the need to better predict the impacts of a future changing climate. 相似文献
17.
Understanding water exchange between groundwater and streams, or groundwater/surface-water relationships, is of primary importance for solving conflicts related to water use and for restoring water ecosystems. To this end, a combination of classic geochemical tools and isotopic tools were tested on the Bassée study site, located in the alluvial plain of the River Seine, to see whether they are relevant for tracing multiple and complex groundwater/surface-water relationships. The Ca/Sr ratio associated with Sr isotopes shows contrasted values and suggests that infiltration of surface water to groundwater increases when approaching the Seine. Furthermore, stable isotopes of the water molecule indicate that water from gravel-pit lakes may infiltrate into groundwater. Tritium and CFC tools confirmed surface-water influence on the Alluvial and Chalk aquifers. This geochemical approach, tested on the Bassée site, clearly demonstrates the need of using various geochemical tools for describing groundwater/surface-water relationships, and can be conclusively addressed to other case studies for helping decision makers in their management of natural water resources. 相似文献
18.
The hydrologic and water-quality characteristics of a small tropical riverine wetland at Ulakwo, near Owerri, Imo State,
Nigeria, were evaluated by analysis of stream hydrographs, the groundwater flow system, and geochemical analyses. This research
is an initial step toward providing information needed to develop a programme of sustainable development of the ecosystem.
The wetland is underlain by a layer of organic debris and hydromorphic soils, which in turn are underlain by an unconfined
alluvial sand aquifer about 80 m thick. Horizontal and upward vertical hydraulic head gradients of about 0.002 and 0.001,
respectively, and the results of a flow-net analysis suggest that considerable amounts of groundwater flow into the wetland.
Low concentrations of Fe, NO3, PO4, and SO4 in the wetland water column are probably due to short-term removal of these nutrients from the surface-water by adsorption
on the surficial wetland organic matter and bottom sediments. The groundwater flow system is important in the maintenance
of the wetland, which probably plays an important role in the flow stabilisation and improvement of the water quality of the
river.
Electronic Publication 相似文献
19.
Surface water bodies interact with underlying aquifer systems, creating a complex flow system and flow paths. In general, a surface water body may be classified as gaining, losing, or flow through on the basis of its interaction with the surrounding aquifer. In the Nile Valley, the quaternary aquifer system is in a direct hydraulic interaction with the River Nile, canals, and drains. In this study, a regional numerical model was developed and used to evaluate the interaction between surface water bodies and the quaternary aquifer system in the Nile Valley. The solution is considered for a quasi three-dimensional, steady-state groundwater flow. The model used simulates the interaction between surface water bodies and groundwater for saturated and unsaturated flow conditions. In addition, a hydrodynamic model was used to simulate different extreme (high and low) scenarios for Nile surface water levels along the distance between Old Aswan Dam and Delta Barrages. Model calibration shows close results, and the model was used to simulate surface water levels. Results indicate that the Nile River acts as a drain for the quaternary aquifer (gaining water from the aquifer), although in the reaches upstream of the main barrages, the Nile loses the water, recharging the aquifer. All other main canals are recharging the aquifer system. The seepage rate depends mainly on the difference in piezometric head between the aquifer system and surface water bodies, as well as the hydraulic conductance of the base layer sediments of the surface water body. The model was used to evaluate the regional water balance for the Nile Valley and to estimate the surface water bodies' gains and losses. 相似文献
20.
Stream-aquifer interactions in the Maules Creek catchment, Namoi Valley, New South Wales, Australia 总被引：1，自引：1，他引：0
The interaction between surface-water streams and groundwater in the Maules Creek catchment of northern New South Wales, Australia has been investigated using a wide range of techniques. Zones of groundwater discharge were mapped by measuring the temperature and fluid electrical-conductivity distribution in bores and surface water. Zones where surface water appears to be recharging the aquifer were investigated by measuring the vertical head gradient between the stream and adjacent bores and by estimates of the decreasing surface flow. Geological heterogeneity appears to be the most significant factor in controlling exchange. Lithological information was assembled using geophysical logging of existing bores, supplemented by the results of electrical resistivity imaging. A preliminary water balance was assembled from the available State records of groundwater abstraction for irrigation, rainfall, evapotranspiration and flow gauging in Maules Creek and the adjacent Namoi River. The analysis has demonstrated the complexity of these coupled systems and gives an indication of the most efficient techniques to be deployed in the field to investigate these complex but important systems. 相似文献