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Sanz D. Valiente N. Dountcheva I. Mu&#;oz-Mart&#;n A. Cassiraga E. G&#;mez-Alday J. J. 《Hydrogeology Journal》2022,30(3):975-988
Hydrogeology Journal - Pétrola Lake in southeast Spain is one of the most representative examples of hypersaline wetlands in southern Europe. The rich ecosystem and environmental importance of... 相似文献
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A non-parametric automatic blending methodology to estimate rainfall fields from rain gauge and radar data 总被引：1，自引：0，他引：1
Carlos A. Velasco-Forero Daniel Sempere-Torres Eduardo F. Cassiraga J. Jaime Gómez-Hernández 《Advances in water resources》2009
Quantitative estimation of rainfall fields has been a crucial objective from early studies of the hydrological applications of weather radar. Previous studies have suggested that flow estimations are improved when radar and rain gauge data are combined to estimate input rainfall fields. This paper reports new research carried out in this field. Classical approaches for the selection and fitting of a theoretical correlogram (or semivariogram) model (needed to apply geostatistical estimators) are avoided in this study. Instead, a non-parametric technique based on FFT is used to obtain two-dimensional positive-definite correlograms directly from radar observations, dealing with both the natural anisotropy and the temporal variation of the spatial structure of the rainfall in the estimated fields. Because these correlation maps can be automatically obtained at each time step of a given rainfall event, this technique might easily be used in operational (real-time) applications. This paper describes the development of the non-parametric estimator exploiting the advantages of FFT for the automatic computation of correlograms and provides examples of its application on a case study using six rainfall events. This methodology is applied to three different alternatives to incorporate the radar information (as a secondary variable), and a comparison of performances is provided. In particular, their ability to reproduce in estimated rainfall fields (i) the rain gauge observations (in a cross-validation analysis) and (ii) the spatial patterns of radar fields are analyzed. Results seem to indicate that the methodology of kriging with external drift [KED], in combination with the technique of automatically computing 2-D spatial correlograms, provides merged rainfall fields with good agreement with rain gauges and with the most accurate approach to the spatial tendencies observed in the radar rainfall fields, when compared with other alternatives analyzed. 相似文献
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David Sanz Santiago Casta?o Eduardo Cassiraga Andr��s Sahuquillo Juan Jos�� G��mez-Alday Salvador Pe?a Alfonso Calera 《Hydrogeology Journal》2011,19(2):475-487
The Mancha Oriental System (MOS, 7,260?km2) is one of the largest aquifers within Spain, and is encompassed by the Jucar River Basin. Over the past 30?years, socioeconomic development within the region has been largely due to intensive use of groundwater resources for irrigating crops (1,000?km2). Groundwater pumping (406 million m3/year) has provoked a steady drop in the groundwater level and a reduction of MOS discharge to the Jucar River. The study aims to characterize the river?Caquifer relationship, to determine the influence that groundwater abstraction has on the river discharge. This research has advanced a three-dimensional large-scale numerical groundwater-flow model (MODFLOW 2000) in order to spatially and temporally evaluate, quantify and predict the river?Caquifer interactions that are influenced by groundwater abstraction in MOS. It is demonstrated that although groundwater abstraction increased considerably from the early 1980s to 2000, the depletion of water stored in the aquifer was lower than might be expected. This is mainly due to aquifer recharge from the Jucar River, induced by groundwater abstraction. The area of disconnection between the river and the water table (i.e. where groundwater head is lower than the riverbed) is found to have spread 20?km downstream from its position before pumping started. 相似文献
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Iordanka Dountcheva David Sanz Eduardo Cassiraga Vassil Galabov Juan José Gómez-Alday 《水文研究》2020,34(25):5134-5145
The objective of this study was to analyse periodicities and the long-term variability of monthly Júcar River–Mancha Oriental Aquifer interactions (RAI) and regionally measured precipitation (PP) with special focus on the correlations between these local hydrological variables and the large climatic patterns governing the Iberian Peninsula, represented by their teleconnection indices – the North Atlantic Oscillation index (NAOi) and the Western Mediterranean Oscillation index (WeMOi). To that end, wavelet analysis has been applied since it not only provides insight into the time-series dynamics but also permits statistical interpretation and correlation analysis. As a result, several periodicities have been detected: intermittent semi-annual periodicity in PP and the NAOi and annual periodicity in the RAI, NAOi and WeMOi time series. Long cycles (approximately 14 years) are also observed in the PP and WeMOi time series. The cross-wavelet spectra show a correlation between the RAI and the rest of the variables on the semi-annual and the annual scales, while wavelet coherence detects common behaviour with longer cycles – 5–6 years between the NAOi and the RAI and cycles of both 1–5 years and 7–10 years between PP and the RAI. Furthermore, results show that the periodicities in the teleconnection indices and precipitation propagate into the RAI with certain lead times: 3 months between the RAI and PP and 6 months between the RAI and the NAOi. The results indicate that the detected periodicities and the coherence between the studied variables could have applications in strategic planning on a river basin scale, taking into account the propagation times and the frequency scale. This methodological approach can be applied into strategic water resource planning independently of the geographical location of the hydrogeological system, the basin size and the climate region. 相似文献
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Nitrate concentrations in multi-aquifer systems are heavily affected by the presence of wellbores (active or abandoned) that
are screened in several aquifers. The spatial variability of hydraulic conductivity in the confining layers has also an important
impact on the concentrations. A synthetic three-dimensional flow and transport exercise was carried in a multi-aquifer system
consisting of two aquifers separated by an aquitard in which 100 vertical wellbores had been drilled. To model the wellbores
and the flow and transport connection between aquifers that they may induce, we assign a high vertical hydraulic conductivity
and a low effective porosity to the cell blocks including the wells. With these parameters, a solute will travel quickly from
one aquifer to the other without being stored in the well itself. The wellbores will act as preferential pathways, and the
solute will move quickly between aquifers according to the hydrodynamic conditions. Not considering these preferential pathways
could induce erroneous interpretations of the solute distribution in an aquifer. We also noted that when there are vertical
wellbores that connect aquifers in a multi-aquifer system, low conductivity in the aquitard enhances the flow of solute through
the wellbores. Time-varying pumping rates induce important fluctuations in nitrate concentrations; therefore, any estimate
of the water quality of the aquifer will depend on the moment when the data has been recorded. Consequently, concentration
maps obtained by interpolation of point samples are seldom a good indicator of the chemical status of groundwater bodies;
alternatively, we recommend complementing the usual interpolated maps with numerical models to gain a true understanding of
the spatial distribution of the solute concentration. 相似文献
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