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1.
The glacially formed northeastern German lowlands are characterized by extensive floodplains, often interrupted by relatively steep moraine hills. The hydrological cycle of this area is governed by the tight interaction of surface water dynamics and the corresponding directly connected shallow groundwater aquifer. Runoff generation processes, as well as the extent and spatial distribution of the interaction between surface water and groundwater, are controlled by floodplain topography and by surface water dynamics. A modelling approach based on extensive experimental analyses is presented that describes the specific water balance of lowland areas, including the interactions of groundwater and surface water, as well as reflecting the important role of time‐variable shallow groundwater stages for runoff generation in floodplains. In the first part, experimental investigations of floodplain hydrological characteristics lead to a qualitative understanding of the water balance processes and to the development of a conceptual model of the water balance and groundwater dynamics of the study area. Thereby model requirements which allow for an adequate simulation of the floodplain hydrology, considering also interactions between groundwater and surface water have been characterized. Based on these analyses, the Integrated Modelling of Water Balance and Nutrient Dynamics (IWAN) approach has been developed. This consists of coupling the surface runoff generation and soil water routines of the deterministic, spatially distributed hydrological model WASIM‐ETH‐I with the three‐dimensional finite‐difference‐based numerical groundwater model MODFLOW and Processing MODFLOW. The model was applied successfully to a mesoscale subcatchment of the Havel River in northeast Germany. It was calibrated for two small catchments (1·4 and 25 km2), where the importance of the interaction processes between groundwater and surface waters and the sensitivity of several controlling parameters could be quantified. Validation results are satisfying for different years for the entire 198 km2 catchment. The model approach was further successfully tested for specific events. The experimental area is a typical example of a floodplain‐dominated landscape. It was demonstrated that the lateral flow processes and the interactions between groundwater and surface water have a major importance for the water balance and periodically superimposed on the vertical runoff generation. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
2.
Using new mass balance methods to estimate gross surface water and groundwater exchange with naturally occurring tracer 222Rn in data poor regions: a case study in northwest China 
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下载免费PDF全文 Given that the concentration of 222Rn in groundwater is much higher than that in surface water and that its radioactive half‐life (3.83 d) is short, 222Rn is an effective tracer of groundwater–surface water interactions. In this study, a new mass balance method is presented, which can be used to estimate specific groundwater–surface water interactions within a river reach. Three possible situations of interaction between groundwater and surface water are considered, and equations based on the mass conservation of 222Rn are formulated for judging specific groundwater–surface water interaction processes and for calculating water flux. A case study was conducted for the Nalenggele River, Northwest China, to demonstrate the usefulness of this method. Samples of river water and groundwater containing 222Rn were collected from the study area to estimate the interactions between groundwater and surface water. The amount of water exchanged during these interactions was estimated and the results show that transformations between groundwater and surface water are frequent along the stream. The 222Rn mass balance method is highly sensitive for studying such interactions, even in areas for which conventional hydrologic data are sparse. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
3.
Surface water and groundwater in the Heihe river basin of China are interconnected and the pattern of water resources exploitation has a direct effect on the interaction of groundwater and surface water, especially on a downstream oasis. A three‐dimensional groundwater flow simulation model with eight model layers was established to simulate the regional groundwater flow in the multilayered aquifer system and the interaction among the rivers, springs, and groundwater. The model was calibrated not only with historical water levels but also with the investigated baseflow and spring flux. The simulation results of the numerical model match reasonably well with the observed groundwater levels, baseflow to rivers, and spring flux. The numerical simulation also demonstrates that the hydraulic connection between the river and the aquifers has transferred from the coupling to decoupling at some reaches. It is suggested that there is a vital need to reduce groundwater withdrawal and to rationalize the use of both groundwater and surface water in order to maintain sustainable development in the study area. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
4.
Assessing regional‐scale spatio‐temporal patterns of groundwater–surface water interactions using a coupled SWAT‐MODFLOW model 下载免费PDF全文
下载免费PDF全文 Ryan T. Bailey Tyler C. Wible Mazdak Arabi Rosemary M. Records Jeffrey Ditty 《水文研究》2016,30(23):4420-4433
Interaction between groundwater and surface water in watersheds has significant impacts on water management and water rights, nutrient loading from aquifers to streams, and in‐stream flow requirements for aquatic species. Of particular importance are the spatial patterns of these interactions. This study explores the spatio‐temporal patterns of groundwater discharge to a river system in a semi‐arid region, with methods applied to the Sprague River Watershed (4100 km2) within the Upper Klamath Basin in Oregon, USA. Patterns of groundwater–surface water interaction are explored throughout the watershed during the 1970–2003 time period using a coupled SWAT‐MODFLOW model tested against streamflow, groundwater level and field‐estimated reach‐specific groundwater discharge rates. Daily time steps and coupling are used, with groundwater discharge rates calculated for each model computational point along the stream. Model results also are averaged by month and by year to determine seasonal and decadal trends in groundwater discharge rates. Results show high spatial variability in groundwater discharge, with several locations showing no groundwater/surface water interaction. Average annual groundwater discharge is 20.5 m3/s, with maximum and minimum rates occurring in September–October and March–April, respectively. Annual average rates increase by approximately 0.02 m3/s per year over the 34‐year period, negligible compared with the average annual rate, although 70% of the stream network experiences an increase in groundwater discharge rate between 1970 and 2003. Results can assist with water management, identifying potential locations of heavy nutrient mass loading from the aquifer to streams and ecological assessment and planning focused on locations of high groundwater discharge. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
Improved simulation of river water and groundwater exchange in an alluvial plain using the SWAT model 总被引：1，自引：0，他引：1 下载免费PDF全文
下载免费PDF全文 X. Sun L. Bernard‐Jannin C. Garneau M. Volk J. G. Arnold R. Srinivasan S. Sauvage J. M. Sánchez‐Pérez 《水文研究》2016,30(2):187-202
Hydrological interaction between surface and subsurface water systems has a significant impact on water quality, ecosystems and biogeochemistry cycling of both systems. Distributed models have been developed to simulate this function, but they require detailed spatial inputs and extensive computation time. The soil and water assessment tool (SWAT) model is a semi‐distributed model that has been successfully applied around the world. However, it has not been able to simulate the two‐way exchanges between surface water and groundwater. In this study, the SWAT‐landscape unit (LU) model – based on a catena method that routes flow across three LUs (the divide, the hillslope and the valley) – was modified and applied in the floodplain of the Garonne River. The modified model was called SWAT‐LUD. Darcy's equation was applied to simulate groundwater flow. The algorithm for surface water‐level simulation during flooding periods was modified, and the influence of flooding on groundwater levels was added to the model. Chloride was chosen as a conservative tracer to test simulated water exchanges. The simulated water exchange quantity from SWAT‐LUD was compared with the output of a two‐dimensional distributed model, surface–subsurface water exchange model. The results showed that simulated groundwater levels in the LU adjoining the river matched the observed data very well. Additionally, SWAT‐LUD model was able to reflect the actual water exchange between the river and the aquifer. It showed that river water discharge has a significant influence on the surface–groundwater exchanges. The main water flow direction in the river/groundwater interface was from groundwater to river; water that flowed in this direction accounted for 65% of the total exchanged water volume. The water mixing occurs mainly during high hydraulic periods. Flooded water was important for the surface–subsurface water exchange process; it accounted for 69% of total water that flowed from the river to the aquifer. The new module also provides the option of simulating pollution transfer occurring at the river/groundwater interface at the catchment scale. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
6.
Yaguang Zhu Yuanzheng Zhai Qingqing Du Yanguo Teng Jinsheng Wang Guang Yang 《水文研究》2019,33(6):945-961
Riverbank filtration (RBF) has been widely used throughout the world as an effective means to regulate surface water and groundwater resources and pretreat raw water for municipal water supply. The quality of the water from a riverside well field and the mixing ratios of surface water and groundwater is primarily impacted by the hydrodynamic processes in the RBF system. The RBF system is largely controlled by the water exploiting system in addition to the natural hydrologic condition of the river–aquifer system. As one of the most important design parameters of the riverside well field, the drawdown of groundwater level greatly determines the water head differences between the river water and groundwater as well as the field flow net, which subsequently impacts the mixing of river water and groundwater and water quality significantly. This study aimed to improve the understanding of the mixing process between the surface water and groundwater and estimate the impact of the RBF on the mixing ratio of surface water–groundwater and water quality quantitatively. A set of field pumping tests with various groundwater level drawdowns were carried out independently and successively at a riverside field with a single pumping well near the Songhua River in Northeast China in August 2017. During these tests, the water levels and hydrochemical parameters of the Songhua River, the adjacent aquifer, and the pumping well were monitored. The dynamic mixing process of the river water and groundwater and water quality under various drawdown conditions were analysed systematically using analytical methods. The results obtained from Dupuit method and the Mirror Image method in conjunction with the Hydrochemical Tracing method showed that the pumping water directly from the river water reached 60% ± 10% after a steady flow net was established. The larger the proportion of the pumping water captured from the river, the better quality of the pumping water was, because the quality of the river water (only limited to some water quality parameters monitored which were minority) was better than that of the groundwater. The results also showed that total Fe, TDS, total hardness, CODMn, and K+ were relatively sensitive to the changes of groundwater drawdown, and their concentrations decreased with an increase in the groundwater drawdown. It can be concluded that both the mixing ratio of the surface water and the groundwater and the water quality of the riverside well field can be regulated through adjusting the designed drawdown of the groundwater level, which is helpful for the design and the optimization of the riverside well water intake engineering. 相似文献
7.
Coastal wetlands are characterized by strong, dynamic interactions between surface water and groundwater. This paper presents a coupled model that simulates interacting surface water and groundwater flow and solute transport processes in these wetlands. The coupled model is based on two existing (sub) models for surface water and groundwater, respectively: ELCIRC (a three‐dimensional (3‐D) finite‐volume/finite‐difference model for simulating shallow water flow and solute transport in rivers, estuaries and coastal seas) and SUTRA (a 3‐D finite‐element/finite‐difference model for simulating variably saturated, variable‐density fluid flow and solute transport in porous media). Both submodels, using compatible unstructured meshes, are coupled spatially at the common interface between the surface water and groundwater bodies. The surface water level and solute concentrations computed by the ELCIRC model are used to determine the boundary conditions of the SUTRA‐based groundwater model at the interface. In turn, the groundwater model provides water and solute fluxes as inputs for the continuity equations of surface water flow and solute transport to account for the mass exchange across the interface. Additionally, flux from the seepage face was routed instantaneously to the nearest surface water cell according to the local sediment surface slope. With an external coupling approach, these two submodels run in parallel using time steps of different sizes. The time step (Δtg) for the groundwater model is set to be larger than that (Δts) used by the surface water model for computational efficiency: Δtg = M × Δts where M is an integer greater than 1. Data exchange takes place between the two submodels through a common database at synchronized times (e.g. end of each Δtg). The coupled model was validated against two previously reported experiments on surface water and groundwater interactions in coastal lagoons. The results suggest that the model represents well the interacting surface water and groundwater flow and solute transport processes in the lagoons. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
8.
Groundwater discharge flux into rivers (riverine groundwater discharge or RGD) is essential information for the conservation and management of aquatic ecosystems and resources. One way to estimate area-integrated groundwater discharge into surface water bodies is to measure the concentration of a groundwater tracer within the water body. We assessed groundwater discharge using 222Rn, a tracer common in many surface water studies, through field measurements, surface water 222Rn mass balance model, and groundwater flow simulation, for the seldom studied but ubiquitous setting of a flooding river corridor. The investigation was conducted at the dam-regulated Lower Colorado River (LCR) in Austin, Texas, USA. We found that 222Rn in both the river water and groundwater in the river bank changed synchronously over a 12-hour flood cycle. A 222Rn mass balance model allowed for estimation of groundwater discharge into a 500-m long reach of the LCR over the flood. The groundwater discharge ranged between negative values (indicating recharge) to 1570 m3/h; groundwater discharge from groundwater flow simulations corroborated these estimates. However, for the dynamic groundwater discharge estimated by the 222Rn box model, assuming whether the groundwater 222Rn endmember was constant or dynamic led to notably different results. The resultant groundwater discharge estimates are also highly sensitive to river 222Rn values. We thus recommend that when using this approach to accurately characterize dynamic groundwater discharge, the 222Rn in near-stream groundwater should be monitored at the same frequency as river 222Rn. If this is not possible, the 222Rn method can still provide reasonable but approximate groundwater discharge given background information on surface water-groundwater exchange time scales. 相似文献
9.
Coupled groundwater flow and heat transport simulation for estimating transient aquifer–stream exchange at the lowland River Spree (Germany) 下载免费PDF全文
下载免费PDF全文 Subsurface flow and heat transport near Freienbrink, NE Germany, was simulated in order to study groundwater–surface water exchange between a floodplains aquifer and a section of the lowland River Spree and an adjacent oxbow. Groundwater exfiltration was the dominant process, and only fast surface water level rises resulted in temporary infiltration into the aquifer. The main groundwater flow paths are identified based on a 3D groundwater flow model. To estimate mass fluxes across the aquifer–surface water interfaces, a 2D flow and heat transport modelling approach along a transect of 12 piezometers was performed. Results of steady‐state and transient water level simulations show an overall high accuracy with a Spearman coefficient ρ = 0.9996 and root mean square error (RMSE) = 0.008 m. Based on small groundwater flow velocities of about 10?7 to 10?6 ms?1, mean groundwater exfiltration rates of 233 l m?2 d?1 are calculated. Short periods of surface water infiltration into the aquifer do not exceed 10 days, and the infiltration rates are in the same range. The heat transport was modelled with slightly less accuracy (ρ = 0.8359 and RMSE = 0.34 °C). In contrast to the predominant groundwater exfiltration, surface water temperatures determine the calculated temperatures in the upper aquifer below both surface water bodies down to 10 m during the whole simulation period. These findings emphasize prevailing of heat conduction over advection in the upper aquifer zones, which seems to be typical for lowland streams with sandy aquifer materials and low hydraulic gradients. Moreover, this study shows the potential of coupled numerical flow and heat transport modelling to understand groundwater–surface water exchange processes in detail. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
10.
Combination of CFCs and stable isotopes to characterize the mechanism of groundwater–surface water interactions in a headwater basin of the North China Plain 下载免费PDF全文
下载免费PDF全文 Shiqin Wang Ruiqiang Yuan Changyuan Tang Xianfang Song Matthew Currell Zhenglun Yang Zhuping Sheng 《水文研究》2018,32(11):1571-1587
Mountainous areas are characterized by steep slopes and rocky landforms, with hydrological conditions varying rapidly from upstream to downstream, creating variable interactions between groundwater and surface water. In this study, mechanisms of groundwater–surface water interactions within a headwater catchment of the North China Plain were assessed along the stream length and during different seasons, using hydrochemical and stable isotope data, and groundwater residence times estimated using chlorofluorocarbons. These tracers indicate that the river is gaining, due to groundwater discharge in the headwater catchment both in the dry and rainy seasons. Residence time estimation of groundwater using chlorofluorocarbons data reveals that groundwater flow in the shallow sedimentary aquifer is dominated by the binary mixing of water approximating a piston flow model along 2 flow paths: old water, carried by a regional flow system along the direction of river flow, along with young water, which enters the river through local flow systems from hilly areas adjacent to the river valley (particularly during the rainy season). The larger mixing ratio of young water from lateral groundwater recharge and return flow of irrigation during the rainy season result in higher ion concentrations in groundwater than in the dry season. The binary mixing model showed that the ratio of young water versus total groundwater ranged from 0.88 to 0.22 and 1.0 to 0.74 in the upper and lower reaches, respectively. In the middle reach, meandering stream morphology allows some loss of river water back into the aquifer, leading to increasing estimates of the ratio of young water (from 0.22 to 1). This is also explained by declining groundwater levels near the river, due to groundwater extraction for agricultural irrigation. The switch from a greater predominance of regional flow in the dry season, to more localized groundwater flow paths in the wet season is an important groundwater–surface water interactions mechanism, with important catchment management implications. 相似文献
11.
A newly Integrated Hydrological Modelling System (IHMS) has been developed to study the impact of changes in climate, land use and water management on groundwater and seawater intrusion (SWI) into coastal areas. The system represents the combination of three models, which can, if required, be run separately. It has been designed to assess the combined impact of climate, land use and groundwater abstraction changes on river, drainage and groundwater flows, groundwater levels and, where appropriate, SWI. The approach is interdisciplinary and reflects an integrated water management approach. The system comprises three packages: the Distributed Catchment Scale Model (DiCaSM), MODFLOW (96 and 2000) and SWI models. In addition to estimating all water balance components, DiCaSM, produces the recharge data that are used as input to the groundwater flow model of the US Geological Survey, MODFLOW. The latter subsequently generates the head distribution and groundwater flows that are used as input to the SWI model, SWI. Thus, any changes in land use, rainfall, water management, abstraction, etc. at the surface are first handled by DiCaSM, then by MODFLOW and finally by the SWI. The three models operate at different spatial and temporal scales and a facility (interface utilities between models) to aggregate/disaggregate input/output data to meet a desired spatial and temporal scale was developed allowing smooth and easy communication between the three models. As MODFLOW and SWI are published and in the public domain, this article focuses on DiCaSM, the newly developed unsaturated zone DiCaSM and equally important the interfacing utilities between the three models. DiCaSM simulates a number of hydrological processes: rainfall interception, evapotranspiration, surface runoff, infiltration, soil water movement in the root zone, plant water uptake, crop growth, stream flow and groundwater recharge. Input requirements include distributed data sets of rainfall, land use, soil types and digital terrain; climate data input can be either distributed or non‐distributed. The model produces distributed and time series output of all water balance components including potential evapotranspiration, actual evapotranspiration, rainfall interception, infiltration, plant water uptake, transpiration, soil water content, soil moisture (SM) deficit, groundwater recharge rate, stream flow and surface runoff. This article focuses on details of the hydrological processes and the various equations used in DiCaSM, as well as the nature of the interface to the MODFLOW and SWI models. Furthermore, the results of preliminary tests of DiCaSM are reported; these include tests related to the ability of the model to predict the SM content of surface and subsurface soil layers, as well as groundwater levels. The latter demonstrates how the groundwater recharge calculated from DiCaSM can be used as input into the groundwater model MODFLOW using aggregation and disaggregation algorithms (built into the interface utility). SWI has also been run successfully with hypothetical examples and was able to reproduce the results of some of the original examples of Bakker and Schaars ( 2005 ). In the subsequent articles, the results of applications to different catchments will be reported. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
12.
Ricardo Oyarzún Sandro Zambra Hugo Maturana Jorge Oyarzún Evelyn Aguirre Nicole Kretschmer 《水文科学杂志》2013,58(12):2193-2204
ABSTRACTThis paper analyses the composition of surface water and shallow groundwater in the Grande River basin, North-Central Chile, using this information to characterize water interactions. Chemical and isotopic data for surface water and groundwater (7 and 6 sampling locations, respectively) were obtained from three sampling campaigns performed in March–April (autumn), August–September (late winter) and December (early summer) 2012. Precipitation samples were also collected. Data was processed using spatial distribution charts, Piper and Stiff diagrams, and multivariate analysis. In general, the results for each method converge on a high degree of connectivity between surface water and shallow groundwater in the study area. Furthermore, approximately a 10% of groundwater contribution to the surface flow discharge was estimated for a particular reach. This multi-method approach was useful for the characterization of surface water–groundwater interactions in the Grande River basin, and may become a suitable and replicable scheme for studies in arid and semi-arid basins facing similar water management challenges.
Editor D. Koutsoyiannis; Associate editor B. Dewals 相似文献
13.
Impact of water transfer on interaction between surface water and groundwater in the lowland area of North China Plain 总被引：1，自引：0，他引：1 下载免费PDF全文
下载免费PDF全文 The contradiction between the freshwater shortage and the large demand of freshwater by irrigation was the key point in cultivated lowland area of North China Plain. Water transfer project brings fresh water from water resource‐rich area to water shortage area, which can in turn change the hydrological cycle in this region. Major ions and stable isotopes were used to study the temporal variations of interaction between surface water and groundwater in a hydrological year after a water transfer event in November 2014. Irrigation canal received transferred Yellow River, with 2.9% loss by evaporation during water transfer process. The effect of transferred water on shallow groundwater decreased with increasing distance from the irrigation canal. Pit pond without water transfer receives groundwater discharge. During dry season after water transfer event, shallow groundwater near the irrigation canal was recharged by lateral seepage and deep percolation of irrigation, whereas shallow groundwater far from irrigation canal was recharged by deep percolation of deep groundwater irrigation. Canal water lost by evaporation was 2.7–17.4%. Influence of water transfer gradually disappeared until March as the water usage of agricultural irrigation increased. In the dry season, groundwater discharged to irrigation canal and pond; 2.2–31.6% canal water and 11.3–20.0% pond water were lost by evaporation. In the rainy season (June to September), surface water was fed mainly by precipitation and surface run‐off, whereas groundwater was recharged by infiltration of precipitation. The two‐end member mix model showed that the mixing ratio of precipitation in pond and irrigation canal were 73–83.4% (except one pond with 28.1%) and 77.3–99.9%, respectively. Transferred water and precipitation were the important recharge sources for shallow groundwater, which decreased groundwater salinity in cultivated lowland area of North China Plain. With the temporary and spatial limitation of water transfer effects, increased water transfer amounts and frequency may be an effective way of mitigating regional water shortage. In addition, reducing the evaporation of surface water is also an important way to increase the utilization of transfer water. 相似文献
14.
Vertical surface water–groundwater exchange processes within a headwater floodplain induced by experimental floods 下载免费PDF全文
下载免费PDF全文 Restoring hydrologic connectivity between channels and floodplains is common practice in stream and river restoration. Floodplain hydrology and hydrogeology impact stream hydraulics, ecology, biogeochemical processing, and pollutant removal, yet rigorous field evaluations of surface water–groundwater exchange within floodplains during overbank floods are rare. We conducted five sets of experimental floods to mimic floodplain reconnection by pumping stream water onto an existing floodplain swale. Floods were conducted throughout the year to capture seasonal variation and each involved two replicate floods on successive days to test the effect of varying antecedent moisture. Water levels and specific conductance were measured in surface water, soil, and groundwater within the floodplain, along with surface flow into and out of the floodplain. Vegetation density varied seasonally and controlled the volume of surface water storage on the floodplain. By contrast, antecedent moisture conditions controlled storage of water in floodplain soils, with drier antecedent moisture conditions leading to increased subsurface storage and slower flood wave propagation across the floodplain surface. The site experienced spatial heterogeneity in vertical connectivity between surface water and groundwater across the floodplain surface, where propagation of hydrostatic pressure, preferential flow, and bulk Darcy flow were all mechanisms that may have occurred during the five floods. Vertical connectivity also increased with time, suggesting higher frequency of floodplain inundation may increase surface water–groundwater exchange across the floodplain surface. Understanding the variability of floodplain impacts on water quality noted in the literature likely requires better accounting for seasonal variations in floodplain vegetation and antecedent moisture as well as heterogeneous exchange flow mechanisms. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
15.
Measurements of groundwater–surface water exchange at three wetland stream sites were related to patterns in benthic productivity as part of the US Geological Survey's Northern Temperate Lakes–Water, Energy and Biogeochemical Budgets (NTL–WEBB) project. The three sites included one high groundwater discharge (HGD) site, one weak groundwater discharge (WGD) site, and one groundwater recharge (GR) site. Large upward vertical gradients at the HGD site were associated with smallest variation in head below the stream and fewest gradient reversals between the stream and the groundwater beneath the stream, and the stream and the adjacent streambank. The WGD site had the highest number of gradient reversals reflecting the average condition being closest to zero vertical gradient. The duration of groundwater discharge events was related to the amount of discharge, where the HGD site had the longest strong-gradient durations for both horizontal and vertical groundwater flow. Strong groundwater discharge also controlled transient temperature and chemical hyporheic conditions by limiting the infiltration of surface water. Groundwater–surface water interactions were related to highly significant patterns in benthic invertebrate abundance, taxonomic richness, and periphyton respiration. The HGD site abundance was 35% greater than in the WGD site and 53% greater than the GR site; richness and periphyton respiration were also significantly greater (p≤0.001, 31 and 44%, respectively) in the HGD site than in the GR site. The WGD site had greater abundance (27%), richness (19%) and periphyton respiration (39%) than the GR site. This work suggests groundwater–surface water interactions can strongly influence benthic productivity, thus emphasizing the importance of quantitative hydrology for management of wetland-stream ecosystems in the northern temperate regions. 相似文献
16.
Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 km3/year during 1998–2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 km3/year during 1998–2002. It is the sum of the net abstraction of 250 km3/year of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/year of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on groundwater table observations, and with estimates of total water storage variations from the GRACE satellites mission. Due to the difficulty in estimating area-averaged seasonal groundwater storage variations from point observations of groundwater levels, it is uncertain whether WaterGAP underestimates actual variations or not. We conclude that WaterGAP possibly overestimates water withdrawals in the High Plains aquifer where impact of human water use on water storage is readily discernible based on WaterGAP calculations and groundwater observations. No final conclusion can be drawn regarding the possibility of monitoring water withdrawals in the High Plains aquifer using GRACE. For the less intensively irrigated Mississippi basin, observed and modeled seasonal groundwater storage reveals a discernible impact of water withdrawals in the basin, but this is not the case for total water storage such that water withdrawals at the scale of the whole Mississippi basin cannot be monitored by GRACE. 相似文献
17.
针对2008年汶川MS 8.0地震后江苏地区的地震观测井水位上升现象,选取了苏18井和井周边地表水进行了水化学和物理分析,研究了井水位异常与地表水和大气降水的补给关系,讨论了井水补给来源及其与高邮-宝应MS 4.9地震的关系。离子含量和氢氧同位素结果表明,苏18井水主要为大气降水成因,存在一定的水岩作用。应用氯离子分析降水对地下水的补给,其结果显示大气降水在井水补给源中占了重要份额,井水位的突然上升与同期降水量增加有一定关系。水库水与苏18井水之间存在水力联系,大气降水增多致使水库水位升高,对该井水位变化有一定的影响。综合分析认为,大气降水的增多致使水库蓄水增加,水库水通过侧向渗透补给造成了2011年苏18井的水位显著升高。苏18井异常不是由构造活动引起的,作为高邮-宝应MS 4.9地震的前兆依据不充分。水化学和物理结合的方法为今后判别地下水位异常干扰提供了依据。 相似文献
18.
《水文科学杂志》2013,58(2)
Abstract Abstract Land development often results in adverse environmental impact for surface and subsurface water systems. For areas close to the coast, land changes may also result in seawater intrusion into coastal aquifers. Due to this, it is important to evaluate potential adverse effects in advance of any land development. For evaluation purposes a combined groundwater recharge model is proposed with a quasi three-dimensional unconfined groundwater flow equation. The catchment water balance for a planned new campus area of Kyushu University in southern Japan, was selected as a case study to test the model approach. Since most of the study area is covered with forest, the proposed groundwater recharge model considers rainfall interception by forest canopy. The results show that simulated groundwater and surface runoff agree well with observations. It is also shown that actual evapotranspiration, including rainfall interception by forest canopy, is well represented in the proposed simulation model. Several hydrological components such as direct surface runoff rate, groundwater spring flow rate to a ground depression, trans-basin groundwater flow etc., were also investigated. 相似文献
19.
In humid upland catchments wetlands are often a prominent feature in the vicinity of streams and have potential implications for runoff generation and nutrient export. Wetland surfaces are often characterized by distinct micro-topography (hollows and hummocks). The effects of such micro-topography on surface–subsurface exchange and runoff generation for a 10 by 20 m synthetic section of a riparian wetland were investigated in a virtual modeling experiment. A reference model with a planar surface was run for comparison. The geostatistically simulated structure of the micro-topography replicates the topography of a peat-forming riparian wetland in a small mountainous catchment in South-East Germany (Lehstenbach). Flow was modeled with the fully-integrated surface–subsurface code HydroGeoSphere. Simulation results showed that the specific structure of the wetland surface resulted in distinct shifts between surface and subsurface flow dominance. Surface depressions filled and started to drain via connected channel networks in a threshold controlled process, when groundwater levels intersected the land surface. These networks expanded and shrunk in a spill and fill mechanism when the shallow water table fluctuated around the mean surface elevation under variable rainfall inputs. The micro-topography efficiently buffered rainfall inputs and produced a hydrograph that was characterized by subsurface flow during most of the year and only temporarily shifted to surface flow dominance (> 80% of total discharge) during intense rainstorms. In contrast the hydrograph in the planar reference model was much “flashier” and more controlled by surface runoff. A non-linear, hysteretic relationship between groundwater level and discharge observed at the study site was reproduced with the micro-topography model. Hysteresis was also observed in the relationship between surface water storage and discharge, but over a relatively narrow range of surface water storage values. Therefore it was concluded that surface water storage was a better predictor for the occurrence of surface runoff than groundwater levels. 相似文献
20.
Over the past century, groundwater levels in California's San Joaquin Valley have dropped by more than 30 m in some areas mostly due to excessive groundwater extraction used to irrigate agricultural lands and sustain a growing population. Between 2012 and 2015, California experienced the worst drought in its recorded history, depleting surface water supplies and further exacerbating groundwater depletion in the region. Due to a lack of groundwater regulation, exact quantities of extracted groundwater in California are unknown and hard to quantify. Recent adoption of the Sustainable Groundwater Management Act has intensified efforts to identify sustainable groundwater use. However, understanding sustainable use in a highly productive agricultural system with an extremely complex surface water allocation system, variable groundwater use, and spatially extensive and diverse irrigation practices is no easy task. Using an integrated hydrologic model coupled with a land surface model, we evaluated how water management activities, specifically a suite of irrigation and groundwater pumping scenarios, impact surface water–groundwater fluxes and storage components and how those activities and the relationships between them change during drought. Results showed that groundwater pumping volume had the most significant impact on long-term water storage changes. A comparison with total water storage anomaly (TWSA) estimates from NASA's Gravity Recover and Climate Experiment (GRACE) provided some insight regarding which combinations of pumping and irrigation matched the GRACE TWSA estimates, lending credibility to these scenarios. In addition, the majority of long-term water storage changes during the recent drought occurred in groundwater storage in the deeper subsurface. 相似文献