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1.
Azizallah Izady Osman A.E. Abdalla Ata Joodavi Akbar Karimi Mingjie Chen Andrew Tompson 《水文研究》2017,31(19):3437-3451
This paper proposes an approach to estimate groundwater recharge using an optimization‐based water‐table fluctuation method combined with a groundwater balance model in an arid hardrock‐alluvium region, located at the Oman–United Arab Emirates border. We introduce an “effective hardrock thickness” term to identify the percentage of the considered hardrock thickness in which effective groundwater flow takes place. The proposed method is based upon a Thiessen polygon zoning approach. The method includes subpolygons to represent specific geologic units and to enhance the confidence of the estimated groundwater recharge. Two linear and 1 nonlinear submodels were developed to evaluate the model components for the calibration (October 1996 to September 2008) and validation (October 2008 to September 2013) periods. Long‐term annual groundwater recharge from rainfall and return flow over the model domain are estimated as 24.62 and 5.71 Mm3, respectively, while the effective groundwater flow circulation is found to occur in the upper 7% of the known hardrock thickness (42 m), confirming conclusions of previous field studies. Considering a total difference in groundwater levels between eastern and western points of the study area of the order of 220 m and a 12‐year monthly calibration period, a weighted root mean squared error in predicted groundwater elevation of 2.75 m is considered quite reasonable for the study area characterized by remarkable geological and hydrogeological diversity. The proposed approach provides an efficient and robust method to estimate groundwater recharge in regions with a complex geological setting in which interaction between fractured and porous media cannot be easily assessed. 相似文献
2.
万全井水位阶变异常幅度与水位观测值的关系 总被引：3，自引：2，他引：1
有研究结果表明,自流井水位发生阶变时,流量与之有同步变化,在此上建立了数学模型：ΔｈＳ０＋ΔＱτ。即含水层流入井孔水量的增量等于水位阶变量所点的体积与流量变化量在一定的时间内排出水管的水体积之和。并根据自流井水位与流量的关系式Ｑ＝Ｃ（２ｇｈ）＾１／２和万全井水位、流量资料,经过公式推导与计算,证明万全井水位阶变异常幅度与水位观测值大小成正比例关系。 相似文献
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Lake Fertõ/Neusiedler See is a steppe lake situated on the Hungarian-Austrian border with a surface area of 309 km2. It is an extremely shallow lake with regulated outflow. 54% of the whole lake and 85% of the Hungarian part (75 km2) is covered by reed. There are numerous reedless areas (inner ponds) of variable size within the reed belt, which is enmeshed with canals connecting the inner ponds with the open water areas. Fundamental differences were recorded in the water chemistry of the three water type areas, open water, canals and inner ponds. The degree of these differences is basically determined by the distance from the open water areas and the water level of the actual years. An extremely high, an average and an extremely low water level year was examined, in order to present the spatial and temporal differences in the water chemistry of the investigated water bodies. Differences due to the water level fluctuation between years in the three different water types are discussed on the basis of electrical conductivity, cation, and anion concentration changes of the water. Our results support the concept of high instability of Lake Fertõ and describe habitats with remarkable temporal and spatial variability. The high influence of water level on habitat conditions at different sites of the lake recommend a carefull water level regulation strategy. 相似文献
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In this work, we study groundwater system temporal scaling in relation to plant water use and near‐river‐stage fluctuations in riparian zones where phreatophytes exist. Using detrended fluctuation analysis (DFA), we investigate the influence of regular diurnal fluctuations due to phreatophyte water use on temporal scaling properties of groundwater level variations. We found that groundwater use by phreatophytes, at the field site on the Colorado River, USA, results in distinctive crossovers (slope changes when the plots are fitted with straight lines) in the logarithm plots of root‐mean‐square fluctuations of the detrended water level time series versus time scales of groundwater level dynamics. For groundwater levels monitored at wells close to the river, we identified one crossover at ～1 day in the scaling characteristics of groundwater level variations. When time scale exceeds 1 day, the scaling properties decrease from persistent to close to 1/f noise, where f is the frequency. For groundwater levels recorded at wells further away from the river, the slope of the straight line fit (i.e. scaling exponent) is smallest when the time scale is between 1 and 3 days. When the time scale is < 1 day, groundwater variations become persistent. When the time scale is between 1 and 3 days, the variations are close to white noise, but return to persistent when the time scale is > 3 days. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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为探讨华北地区飑线天气对深井水位干扰的特征和影响机制,以2017年9月21日发生在华北中部的一次飑线事件为例,使用时频分析和线性回归等方法系统地诊断了此次飑线对无极、辛集、永清和宁晋等四口千米级深井的水位扰动特征。结果表明：在宏观层面,飑线过境各深井时会引起气压快速涌升,在气压的激励下,深井水位出现了即时的脉冲状波动,该干扰的持续时间可长达127 min;此次飑线过程中周期性气压波动的主频段为15—25 cpd,在该频段内,各深井水位与气压扰动的形态高度负相关,相关系数均低于−0.95,气压系数主要集中在−4.9—−6.9 mm/hPa之间。
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AbstractThis study analyses the statistical and dynamic properties of time series of mean annual groundwater levels for the years 1961–2000, with the purpose of preparing reference statistics for the study period. Data came from 62 measurement stations of the groundwater observation network of the Institute of Meteorology and Water Management—the National Research Institute IMGW-PIB—located across the Wielkopolska Lowland (western Poland). Station-grouping criteria were as follows: the availability of a 40-year measurement series, spatial location, as well as separation of the aquifer from the surface. For estimating the time series structure of groundwater levels, the following stationarity tests were conducted: the augmented Dickey-Fuller (ADF) test and the Kwiatkowski-Phillips-Schmidt-Shin (KPSS) test, with positive results in 44% of the stations, the majority comprising a group that represents confined aquifers. Their non-stationarity was attributed to the presence of a long-term stochastic trend. In the majority of cases the groundwater-level frequency distributions were within the group of platykurtic distributions, right asymmetrical. In the period studied, 62% of the series showed a downward tendency of groundwater levels, including 45% for which the trend was statistically significant; a rising trend was only statistically significant in half of the series. The masking effect of anthropogenic factors was indicated as a fundamental element interfering with the statistical properties of the groundwater observation series in the period 1961–2000 in the Wielkopolska Lowland. This information can be of use for the management and protection of water resources and in prognostic studies on modifying aquiferous systems with recorded water deficits.
Editor D. Koutsoyiannis; Associate editor T. Ouarda 相似文献
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Relative little is known about the interaction between climate change and groundwater. Analysis of aquifer response to climatic variability could improve the knowledge related to groundwater resource variations and therefore provides guidance on water resource management. In this work, seasonal and annual variations of groundwater levels in Kumamoto plain (Japan) and their possible interactions with climatic indices and El Niño Southern Oscillation (ENSO) were analyzed statistically. Results show the following: (1) The water level in the recharge area mainly fluctuates at 1‐ and 2‐year periods, whereas the significant periodicity for water level oscillation in the coastal aquifer is 0.5 year. (2) The aquifer water levels are possibly influenced by variability in precipitation, air temperature, barometric pressure, humidity variances and ENSO. Relative high correlations and large proportions of similarities in wavelet power patterns were found between these variables and water levels. (3) Aquifer response to climatic variances was evaluated using cross wavelet transform and wavelet coherence. In recharging aquifers, the ENSO‐induced annual variations in precipitation, air temperature, humidity and barometric pressure affect aquifer water levels. The precipitation, air temperature and humidity respond to ENSO with a 4‐, 6‐ and 8‐month time lag, respectively, whereas the ENSO imparts weak influence on the barometric pressure. Significant biennial variation of water levels during 1991–1995 is caused primarily by precipitation and humidity variations. In the coastal aquifer, the 0.5‐year variability in ENSO is transferred by precipitation, barometric pressure and humidity to aquifer water levels, and the precipitation/humidity influence is more significant comparing with the barometric pressure. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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本文基于测深反演结果, 通过数值模拟定性分析了地下水位和降雨对周至地电台地电阻率观测的影响; 同时利用褶积算法定量分析了降雨对该台NS向和NE向地电阻率观测的短期影响和长趋势影响.结果表明, 周至地电台地电阻率年变主要由地表薄层介质电阻率季节变化引起, 受地下水位变化影响不明显. 降雨对NS向和NE向地电阻率观测值的影响在短期内与观测结果一致, 表现为增加; 但长期趋势则与观测结果呈负相关关系.根据数值模拟分析认为, 这种变化与降雨及其渗透深度有关.分析结果与实际观测结果一致, 为正确认识周至地电台地电阻率观测与异常判定提供合理的理论依据. 相似文献
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昆仑山8.1级地震在四川省地震地下水观测网中引起了大多数深井水位记录的大幅度波动,数字化水位仪LN-3和大多数浮子式机械水位仪SW40-1均记录到水震波,同一口井两种不同仪器水震波的记录结果有差异,相邻井的记录不同,同震阶变结果表明除北部受张应力外主要受压应力,地震还引起了红旗水库水体冒泡,起大旋涡,库水东西对流的现象。 相似文献
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An investigation was carried out to understand the role of water level fluctuation on major‐ion chemistry of groundwater in the Palar and Cheyyar river basins, southern India. As groundwater is the only major source of water for agricultural and drinking purposes in this area, it is important to know the effect of geological formations and agricultural activities on groundwater chemistry. Groundwater samples were collected once a month from 43 wells (641 samples in total), from January 1998 to June 1999, and analysed for major ions. The results indicate that the major‐ion chemistry of the groundwater varies with respect to space. Groundwater occurring near the River Palar has a high concentration of major ions except calcium, due to the absence of any recharge from the river, whereas lower concentrations of major ions were observed in the central part of the study area due to the recharge of fresh water from a number of surface reservoirs. The major‐ion chemistry of the study region is controlled by both mineral dissolution and anthropogenic activities. The relative contributions of mineral dissolution and anthropogenic contamination are estimated by a stoichiometric approach, which suggests that mineral dissolution is the dominant process in both the formations. The relation between water level fluctuations and major‐ion chemistry indicates that major‐ion chemistry is also greatly influenced by the water level fluctuations in different geological formations. Thus, the major‐ion chemistry of groundwater in this region is greatly influenced by mineral dissolution, anthropogenic activities and water level fluctuations in different geological formations. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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Using lake Stechlin in northeastern Germany as an example of a small groundwater‐feed lake without surface inflows and outflows, we estimated the temporal scales and the variability ranges of the net groundwater contribution to the lake water budget. High‐resolution water level measurements by a bottom‐mounted pressure logger provided the background for the estimation of the total lake water budget. This method has demonstrated reliability for estimation of lake level variations during periods ranging from subdiurnal to perennial. The typical amplitudes of the synoptic‐to‐perennial variability characterizing the groundwater climate of lake Stechlin are estimated by comparing the two subsequent years 2006 and 2007; one of these years shows an extremely high, and the other an extremely low, annual precipitation–evaporation balance. The net groundwater flow, estimated as the difference between the total water budget and the precipitation–evaporation balance at the surface, revealed synoptic effects of lake water exfiltration into the groundwater aquifer following strong precipitation events. Perennial variations between wet and dry years superimposed seasonal oscillations. The probable origin of the latter is seasonality in the groundwater level on the watershed, although the exact amplitudes are subject to further quantification on account of seasonality in the evaporation estimation error. The results emphasize the non‐stationary behaviour of groundwater flow on timescales shorter than climatic ones. The analysis yielded a net quantitative relationship between groundwater flow and water balance at the lake surface: The water level changes in the lake due to evaporation and precipitation are damped to 60% because of the lake–groundwater exchange by means of intermittent infiltration and exfiltration events. Assuming the remaining 40% of the surface water budget may potentially result in perennial water level variability, we estimated an effect of the precipitation decrease on the lake water budget as predicted by the regional climate scenarios for the next century. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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R. P. Kane 《Pure and Applied Geophysics》1988,127(1):143-154
The long-term variation of total ozone is studied for 1957 up to date for different latitude zones. The 3-year running averages show that, apart from a small portion showing parallelism with sunspot cycles, the trends in different latitude zones are dissimilar. In particular, where northern latitudes show a rising trend, the southern latitudes show an opposite (decreasing) trend. In the north-temperate group, Europe, North America and Asia show dissimilar trends. The longer data series (1932 ownards) for Arosa shows, besides a solar-cycle-dependent component, a steady level during 1932–1953 and a down-trend thereafter up to date. Very localised but long-lasting circulation patterns, different in different geographical regions, are indicated. 相似文献
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对岫岩２号井水位自１９８７年末在正常年变中出现急剧下降至１９９１年５月降至最低点后转急剧上升的动态进行分析。通过收集区域地质,矿山排水等有关资料进行定性解释,然后用地下水动力学法计算矿坑排水影响半径。结果表明,岫岩２号井水位之所以产生急剧下降又转回升的动态是由于矿山排水影响所致,并非地震前兆。 相似文献
16.
Ping Guo Hai Xiao Feng Gao Zijuan Li Huan Hu Qianheng Zhang Zhenyao Xia Mingyi Li Yueshu Yang 《水文研究》2021,35(7):e14282
Periodic submersion and exposure due to the operation of the Three Gorges Reservoir (TGR) alter the soil properties and plant characteristics at different elevations within the water level fluctuation zone (WLFZ), possibly influencing the soil detachment capacity (Dc), but the vertical heterogeneity of this effect is uncertain. Soil samples were taken from 6 elevation segments (5 m per segment) along a slope profile in the WLFZ of the TGR to clarify the vertical heterogeneity of Dc. Scouring experiments were conducted at 5 slope gradients (17.6%, 26.8%, 36.4%, 46.6%, and 57.7%) and 5 flow rates (10, 15, 20, 25, and 30 L min−1) to determine Dc. The results indicate that the soil properties and biomass parameters of the WLFZ exhibit strongly vertical heterogeneity. Dc fluctuates with increasing elevation, with maximum and minimum average values at elevations of 145–150 m and 165–170 m, respectively. Linear equations accurately describe the relationships between Dc and hydrodynamic parameters, for which the shear stress (τ), stream power (ω), and unit energy of water-carrying section (E) perform much better than the unit stream power (U). Furthermore, a clear improvement is achieved when using a general index of flow intensity to estimate Dc. Furthermore, Dc is significantly and negatively correlated with the mean weight diameter (MWD, p < 0.05) and organic matter content (p < 0.01) but not significantly correlated with other soil properties (p > 0.05). The rill erodibility at elevations of 145–150 m and 170–175 m is greater than that at other elevations. The critical hydraulic parameters were highest in the 165–170 m segments. Both the rill erodibility and the critical parameters fluctuate vertically along the sloping surface. This research highlights the vertical heterogeneity of Dc and is helpful for better understanding the mechanisms responsible for soil detachment in the WLFZ of the TGR. 相似文献
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Groundwater in coastal areas is commonly disturbed by tidal fluctuations. A two‐dimensional analytical solution is derived to describe the groundwater fluctuation in a leaky confined aquifer system near open tidal water under the assumption that the groundwater head in the confined aquifer fluctuates in response to sea tide whereas that of the overlying unconfined aquifer remains constant. The analytical solution presented here is an extension of the solution by Sun for two‐dimensional groundwater flow in a confined aquifer and the solution by Jiao and Tang for one‐dimensional groundwater flow in a leaky confined aquifer. The analytical solution is compared with a two‐dimensional finite difference solution. On the basis of the analytical solution, the groundwater head distribution in a leaky confined aquifer in response to tidal boundaries is examined and the influence of leakage on groundwater fluctuation is discussed. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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Abstract The changes in the isotopic composition of, and the groundwater level in, the Choshui River alluvial fan near the ruptured Chelungpu Fault during and following the 1999 ( M w = 7.5) Chi-Chi earthquake in Taiwan are reported. Three aspects of the hydrological changes are noticed. First, following the Chi-Chi earthquake, the lower aquifers beneath the Choshui River fan showed a significant shift in isotopic composition towards that of the surface water in the Choshui River, suggesting enhanced exchanges of water between the river and the groundwater. Second, in some wells, water levels and isotopic compositions in different aquifers converged to the same respective values during the Chi-Chi earthquake, suggesting coseismic exchanges of water between the different aquifers, which implies enhanced permeability due perhaps to the fracturing and breaching of aquitards between the aquifers. Third, the pattern of the coseismic water-level response is distinctly different from that of the shift in the isotopic composition, suggesting that they were produced by different mechanisms. 相似文献
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Groundwater is the most important and valuable natural resources especially in coastal urban environment where surface water is insufficient to satisfy the water requirement. Puri city is located on the east coast of India where groundwater is the only source available to meet city water supply. As the city is situated on the sandy aquifer, quality of groundwater is deteriorating because of anthropogenic activities, lack of sewerage system, etc. The objective of the study was to assess the groundwater fluctuation during post‐monsoon and summer with respect to hydrogeological conditions, topography, and groundwater consumption pattern of the city. For this assessment and analysis, Geographic Information System (GIS) was used to visualize topography of the area through digital elevation model (DEM) and distribution of groundwater contours spatially and temporally. The probable areas prone to contamination were identified based on aquifer property and depths to water table below ground. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献