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1.
Recently, Ras Sudr (the delta of Wadi Sudr) area received a great amount of attention due to different development expansion activities directed towards this area. Although Quaternary aquifer is the most prospective aquifer in Ras Sudr area, it has not yet completely evaluated. The present work deals with the simulation of the Quaternary groundwater system using a three-dimensional groundwater flow model. MODFLOW code was applied for designing the model of the Ras Sudr area. This is to recognize the groundwater potential as well as exploitation plan of the most prospective aquifer in the area. The objectives were to determine the hydraulic parameters of the Quaternary aquifer, to estimate the recharge amount to the aquifer, and to determine the hydrochemistry of groundwater in the aquifer. During this work, available data has been collected and some field investigation has been carried out. Groundwater flow model has been simulated using pilot points’ method. SEAWAT has been also applied to simulate the variable-density flow and sea water intrusion from the west. It can be concluded that: (1) the direction of groundwater flow is from the east to the west, (2) the aquifer system attains a small range of log-transformed hydraulic conductivity. It ranges between 3.05 and 3.35 m/day, (3) groundwater would be exploited by about 6.4 × 106 m3/year, (4) the estimated recharge accounts for 3 × 106 m3/year, (5) an estimated subsurface flow from the east accounts for 2.7 × 106 m3/year, (6) the increase of total dissolved solids (TDS) most likely due to dilution of salts along the movement way of groundwater from recharge area to discharge area in addition to a contribution of sea water intrusion from the west. Moreover, it is worth to note that a part of TDS increase might be through up coning from underlying more saline Miocene sediments. It is recommended that: (1) any plan for increasing groundwater abstraction is unaffordable, (2) reliable estimates of groundwater abstraction should be done and (3) automatic well control system should be made.  相似文献   

2.
The Krishni–Yamuna interstream area is a micro-watershed in the Central Ganga Plain and a highly fertile track of Western Uttar Pradesh. The Sugarcane and wheat are the major crops of the area. Aquifers of Quaternary age form the major source of Irrigation and municipal water supplies. A detailed hydrogeological investigation was carried out in the study area with an objective to assess aquifer framework, groundwater quality and its resource potential. The hydrogeological cross section reveals occurrence of alternate layers of clay and sand. Aquifer broadly behaves as a single bodied aquifer down to the depth of 100 m bgl (metre below ground level) as the clay layers laterally pinch out. The depth to water in the area varies between 5 and 16.5 m bgl. The general groundwater flow direction is from NE to SW with few local variations. An attempt has been made to evaluate groundwater resources of the area. The water budget method focuses on the various components contributing to groundwater flow and groundwater storage changes. Changes in ground water storage can be attributed to rainfall recharge, irrigation return flow and ground water inflow to the basin minus baseflow (ground water discharge to streams or springs), evapotranspiration from ground water, pumping and ground water outflow from the basin. The recharge is obtained in the study area using Water table fluctuation and Tritium methods. The results of water balance study show that the total recharge in to the interstream region is of the order of 185.25 million m3 and discharge from the study area is of the order of 203.24 million m3, leaving a deficit balance of −17.99 million m3. Therefore, the present status of groundwater development in the present study area has acquired the declining trend. Thus, the hydrogeological analysis and water balance studies shows that the groundwater development has attained a critical state in the region.  相似文献   

3.
The Beijing-Tianjin-Hebei Plain (BTHP) is the political, economic and cultural center of China, where groundwater is the main source of water supply to support social and economic development. Continuous overdraft of the resources has caused a persistent decline of groundwater level and formed a huge cone of depression at a regional scale. This paper addresses current groundwater situation over the BTHP area. The paper also delineates the groundwater flow field, using groundwater level data, in order to provide an effective method for the restoration of groundwater level and associated water resources management. Based on the analysis of multiple factors, such as groundwater level, soil salinization, ground subsidence, groundwater recharge and storage, urban underground space security, formation of fractures, and seawater intrusion, the threshold for groundwater level restoration is defined, and some measures for groundwater over-exploitation management are accordingly proposed. The study shows that: (i) Since the 1980s to 2020, shallow groundwater level in the western part of the BTHP area has dropped by 25 m to 60 m, while the cumulative decline of deep groundwater in the central and eastern regions is in the range of 40–80 m; (ii) The water table of the shallow groundwater within the depression zone over the Western Piedmont Plain should be controlled in the range of 15–30 m below ground level (mbgl), while the depth of groundwater level in large and medium-sized urban areas should be controlled within 20–30 mbgl. The groundwater level in the resource preservation area should be controlled within 10–15 mbgl, and the groundwater level in the area with identified soil salinization in the central and eastern plain should be controlled within 3–10 mbgl. However, for the deep groundwater in the central and eastern plainwater, the main focus of the resources management is to control the land subsidence. The water level in the severe land subsidence area should be controlled within 45–60 mbgl, and in the general subsidence area should be controlled within 30–45 mbgl; (iii) Based on the water level recovery threshold and proposed groundwater overdraft management program, if the balance of abstraction and recharge is reached in 2025, the shallow groundwater abstraction needs to be gradually reduced by about 2×108 m3. Meanwhile, the ecological water replenishment of rivers through the South-to-North Water Transfer Project should be increased to 28.58×108 m3/a, and the deep groundwater abstraction needs to be gradually reduced by 2.24×108 m3. To reach the target of shallow groundwater level in 2040, surface water replacement is recommended with a rate of 25.77×108 m3/a and the ecological water replenishment of rivers in the South-to-North Water Diversion Project should reach 33.51×108 m3/a. For deep groundwater recovery, it is recommended to replace the deep freshwater extraction with the utilization of shallow salt water by 2.82×108 m3 , in addition to the amount of 7.86×108 m3 by water diversion. The results are of great significance to the remediation of groundwater over-exploitation, the regulation of water resources development and utilization, and ecological protection in Beijing-Tianjin-Hebei plain.  相似文献   

4.
Groundwater is a major source of water for agricultural and domestic requirements in western Uttar Pradesh. Due to increasing agricultural requirements the abstraction of groundwater has increased manifold in the last two-to-three decades. The quaternary alluvium hosts the aquifer in the region. The study area forms a part of Yamuna-Krishni interfluve. Although the area hosts potential aquifers these have been adversely affected by poor management. For effective groundwater management of a basin it is essential that a careful water balance study should be carried out. Keeping this in mind groundwater flow modelling was attempted to simulate the behaviour of the flow system and evaluate the water balance. The groundwater flow modelling was carried out. The horizontal flows, seepage losses from unlined canals, recharge from rainfall and irrigation return flows were applied using different boundary packages available in Visual MODFLOW, Pro 4.1. The river-aquifer interaction was simulated using the river boundary package. Hydraulic conductivity values were applied to specific zones and these ranged from 9.8 to 26.6m/day. Recharge due to rainfall and irrigation returns were assigned to respective zones. Pumping rates of 500m3/day, 1000m3/day, 1500m3/day, 2000m3/day and 2500m3/day were applied to appropriate areas of the model to simulate areas of stress. The zone budget shows a water balance deficit for the period June 2006 to June 2007. The total recharge to the study area is 160.21 million m3 (Mcum). The groundwater draft through pumping is of the order of 233.56 Mcum, thus leaving a deficit balance of −73.35 Mcum. The sensitivity of the model to input parameters was tested by varying the parameters of interest over a range of values, monitoring the response of the model and determining the root mean square error of the simulated groundwater heads to the measured heads. These analyses showed that the model is most sensitive to hydraulic conductivity and recharge parameters. Three scenarios were considered to predict aquifer responses under varied conditions of groundwater bstraction.  相似文献   

5.
Groundwater potential map is important for environmental assessment and water resources management. In this work, a groundwater recharge potential map was established for the watershed of Oued Djelfa Hadjia in Algeria, based on new multiparameters hybrid model. The model has hydroclimatic parameters, geological settings, slope factor, and stream network density factor as inputs. The groundwater recharge estimated by the model range from 0.71 to 14 mm. The model allows delineation of potential area of recharge. The total water abstraction in Djelfa city is about of 14 hm3; however, the calculated groundwater recharge is about 3 mm/year (min 0.71 mm and max 14 mm), which correspond to an average recharge volume of 3.9 hm3 which mean that the aquifer is under over exploitation.  相似文献   

6.
Modeling of groundwater flow for Mujib aquifer, Jordan   总被引：4，自引：0，他引：4  
Jordan is an arid country with very limited water resources. Groundwater is the main source for its water supply. Mujib aquifer is located in the central part of Jordan and is a major source of drinking water for Amman, Madaba and Karak cities. High abstraction rates from Mujib aquifer during the previous years lead to a major decline in water levels and deterioration in groundwater quality. Therefore, proper groundwater management of Mujib aquifer is necessary; and groundwater flow modeling is essential for proper management. For this purpose, Modflow was used to build a groundwater flow model to simulate the behavior of the flow system under different stresses. The model was calibrated for steady state condition by matching observed and simulated initial head counter lines. Drawdown data for the period 1985–1995 were used to calibrate the transient model by matching simulated drawdown with the observed one. Then, the transient model was validated by using drawdown data for the period 1996–2002. The results of the calibrated model showed that the horizontal hydraulic conductivity of the B2/A7 aquifer ranges between 0.001 and 40m/d. Calibrated specific yield ranges from 0.0001 to 0.15. The water balance for the steady state condition of Mujib aquifer indicated that the total annual direct recharge is 20.4 × 106m3, the total annual inflow is 13.0 × 106 m3, springs discharge is 15.3 × 106 m3, and total annual outflow is 18.7 × 106 m3. Different scenarios were considered to predict aquifer system response under different conditions. The results of the sensitivity analysis show that the model is highly sensitive to horizontal hydraulic conductivity and anisotropy and with lower level to the recharge rates. Also the model is sensitive to specific yield  相似文献   

7.
Dar-es-Salaam City gets water supply from surface water and groundwater. The groundwater is used to supplement surface water supply and has increasingly become a major source of water supply in the city. The study area comprises three major parts: the central coastal plain with quaternary fluvial–deltaic sediments, the deltaic Mio-Pliocene clay-bound sands and gravels in the northwest and southeast and the Lower Miocene fluviatile sandstones of Pugu Hills in the west of the study area. The main objective of this study was to quantify the integrated water balance. The major source of renewable groundwater in the aquifer is rainfall. Hence, the average recharge of 256.2 mm/year (for the year 2006) to the aquifer was estimated using the balance method of Thornthwaite and Mather, which is equal to 99.4 hm3/year for the whole alluvial aquifer. This value was balanced with total groundwater abstraction of 8.59 hm3/year, baseflow to rivers of 75.7 hm3/year and discharge into the sea (15.11 hm3/year).  相似文献   

8.
Water-table elevation measurements and aquifer parameter estimates are rare in alpine settings because few wells exist in these environments. Alpine groundwater systems may be a primary source of recharge to regional groundwater flow systems. Handcart Gulch is an alpine watershed in Colorado, USA comprised of highly fractured Proterozoic metamorphic and igneous rocks with wells completed to various depths. Primary study objectives include determining hydrologic properties of shallow bedrock and surficial materials, developing a watershed water budget, and testing the consistency of measured hydrologic properties and water budget by constructing a simple model incorporating groundwater and surface water for water year 2005. Water enters the study area as precipitation and exits as discharge in the trunk stream or potential recharge for the deeper aquifer. Surficial infiltration rates ranged from 0.1–6.2×10?5 m/s. Discharge was estimated at 1.28×10?3 km3. Numerical modeling analysis of single-well aquifer tests predicted lower specific storage in crystalline bedrock than in ferricrete and colluvial material (6.7×10?5–2.0×10?3 l/m). Hydraulic conductivity in crystalline bedrock was significantly lower than in colluvial and alluvial material (4.3×10?9–2.0×10?4 m/s). Water budget results suggest that during normal precipitation and temperatures water is available to recharge the deeper groundwater flow system.  相似文献   

9.
The dynamics of artificial recharge of winter surface flows coupled with increased summer groundwater use for irrigation in the Sokh aquifer (Central Asia) have been investigated. Water release patterns from the giant Toktogul reservoir have changed, as priority is now given to hydropower generation in winter in Kyrgyzstan. Winter flows have increased and summer releases have declined, but the Syr Darya River cannot pass these larger winter flows and the excess is diverted to a natural depression, creating a 40?×?109m3 lake. A water balance study of all 18 aquifers feeding the Fergana Valley indicated the feasibility of winter groundwater recharge in storage created by summer abstraction. This modeling study examines the dynamics of the process in one aquifer over a 5-year period, with four scenarios: the current situation; increased groundwater abstraction of around 625 million (M) m3/year; groundwater abstraction with an artificial recharge of 144 Mm3/year, equivalent to the volume available in low flow years in the Sokh River; and with a larger artificial recharge of 268 Mm3/year, corresponding to high flow availability. Summer surface irrigation diversions can be reduced by up to 350 Mm3 and water table levels can be lowered.  相似文献   

10.
The Kali-Hindon inter-stream region extends over an area of 395 km2 within the Ganga-Yamuna interfluve. It is a fertile tract for sugarcane cultivation. Groundwater is a primary resource for irrigation and industrial purposes. In recent years, over-exploitation has resulted in an adverse impact on the groundwater regime. In this study, an attempt has been made to calculate a water balance for the Kali-Hindon inter-stream region. Various inflows and outflows to and from the aquifer have been calculated. The recharge due to rainfall and other recharge parameters such as horizontal inflow, irrigation return flow and canal seepage were also evaluated. Groundwater withdrawals, evaporation from the water table, discharge from the aquifer to rivers and horizontal subsurface outflows were also estimated. The results show that total recharge into the system is 148.72 million cubic metres (Mcum), whereas the total discharge is 161.06 Mcum, leaving a deficit balance of −12.34 Mcum. Similarly, the groundwater balance was evaluated for the successive four years. The result shows that the groundwater balance is highly sensitive to variation in rainfall followed by draft through pumpage. The depths to water level are shallow in the canal-irrigated northern part of the basin and deeper in the southern part. The pre-monsoon and post-monsoon water levels range from 4.6 to 17.7 m below ground level (bgl) and from 3.5 to 16.5 m bgl respectively. It is concluded that the groundwater may be pumped in the canal-irrigated northern part, while withdrawals may be restricted to the southern portion of the basin, where intense abstraction has led to rapidly falling water table levels.  相似文献   

11.
The Nubia Sandstone aquifer system is one of the most extensive groundwater systems in North Africa, covering an area of about 2,000,000 km2, including parts of Egypt, Libya, Sudan, and Chad. In the Western Desert of Egypt, the Nubian formation has a thermal gradient of 1.1–5°C 100 m–1 with the exception of the East Oweinat area, located in the southern part of the Western Desert. This is the only part of this huge system where ground-water occurs under unconfmed conditions in an area where the Nubian sandstone crops out and is underlain by shallow basement rocks; in this area groundwater has no thermal characteristics. The aquifer system in the East Oweinat area attains a relatively high hydraulic conductivity. The direction of groundwater flow is generally northeastwards but is distorted at faults and fracture zones. Chemical analyses of groundwater in the area indicate a low salt content and suitability for irrigation purposes. As the estimated recharge to the area is low compared with the foreseen irrigation water requirement, the development of groundwater in the East Oweinat should be based on groundwater mining. Although the evaluation of the groundwater resources in East Oweinat has indicated that groundwater can be extracted at a rate of 4.7×106 m3 d–1, the long-term economics of extraction that can sustain large-scale development projects has to be assessed.  相似文献   

12.
Operation of a wellfield tapping a deep-seated aquifer system depends upon the recharge from outside the aquifer system under the condition of exploitation. This kind of replenishment, however, is not learned until the wellfield is in operation and a quarry-pumping test is often needed in the investigation of the wellfield. A deep-seated confined aquifer consisting of Ordovician carbonates occurs in the Chezhoushan Syncline crossing the border of Tianjin and Hebei in northern China. The Ordovician aquifer is believed to receive recharge through leakage from the overlying Quaternary aquifer only in the northeastern part of the syncline. The Ninghebei wellfield is planned to produce 100,000 m3/day of groundwater from the Ordovician aquifer for water supply. A three-dimensional transient numerical model was established based on a hydrogeologic survey, especially a quarry-pumping test conducted in 2003. The model was calibrated with the water-level data of the quarry-pumping test and used to predict the future water-level changes that might result from the three proposed exploitation scenarios. A 20 year predictive simulation results indicate that hydraulic heads decline rapidly in the early months, decline slowly in the following years and reach a steady state in the late period with a maximum drawdown of 52.09 m under the maximum total withdrawal rate of 120,000 m3/day from the Ordovician aquifer, and that the infer-aquifer recharge through leakage from the Quaternary aquifer can balance the withdrawal rate.  相似文献   

13.
The groundwater of major karst systems and submarine springs in the coastal limestone aquifer of Syria has been investigated using chemical and isotopic techniques. The δ18O values of groundwater range from ?6.8 to ?5.05‰, while those for submarine springs vary from ?6.34 to +1.08‰ (eastern Mediterranean seawater samples have a mean of +1.7‰). Groundwater originates from the direct infiltration of atmospheric water. Stable isotopes show that the elevation of the recharge zones feeding the Banyas area (400–600 m a.s.l.) is higher than that feeding the Amrit area (100–300 m a.s.l.). The 18Oextracted (18O content of the seawater contribution) for the major submarine springs suggests a mean recharge area elevation of 600–700 m a.s.l., and lower than 400 m a.s.l. for the spring close to Amrit. Based on the measured velocity and the percentage of fresh water at the submarine springs outlet, the estimated discharge rate is 350 million m3/year. The tritium concentrations in groundwater (1.6–5.9 TU) are low and very close to the current rainfall values (2.9–5.6 TU). Adopting a model with exponential time distribution, the mean turnover time of groundwater in the Al-sen spring was evaluated to be 60 years. A value of about 3.7 billion m3 was obtained for the maximum groundwater reservoir size.  相似文献   

14.
Groundwater degradation from irrigated agriculture is of concern in semi-arid northern China. Data-scarcity often means the causes and extent of problems are not fully understood. An irrigated area in Inner Mongolia was studied, where abstraction from an unconfined Quaternary aquifer has increased threefold over 20 years to 20 million m3/year; groundwater levels are falling at up to 0.5 m/year; and groundwater is increasingly mineralised (TDS increase from 400 to 700–1,900 mg/L), with nitrate concentrations up to 137 mg/L N. Residence-time (chlorofluorocarbons), stable-isotope and hydrogeochemical indicators helped develop a conceptual model of groundwater system evolution, demonstrating a direct relationship between modern water proportion and the degree of groundwater mineralisation, indicating that irrigation-water recycling is reducing groundwater quality. The investigations suggest that before irrigation development, active recharge to the aquifer from wadis significantly exceeded groundwater inflow from nearby mountains, previously held to be the main groundwater input. Away from active wadis, groundwater is older with a probable pre-Holocene component. Proof-of-concept groundwater modelling supports geochemical evidence, indicating the importance of wadi recharge and irrigation return flows. Engineering works protecting the irrigated area from flooding have reduced good quality recharge; active recharge is now dominated by irrigation returns, which are degrading the aquifer.  相似文献   

15.
The Nyamandhlovu aquifer is the main water resource in the semi-arid Umguza district in Matebeleland North Province in Zimbabwe. The rapid increase in water demand in the city of Bulawayo has prompted the need to quantify the available groundwater resources for sustainable utilization. Groundwater recharge estimation methods and results were compared: chloride mass balance method (19–62 mm/year); water-table fluctuation method (2–50 mm/year); Darcian flownet computations (16–28 mm/year); 14C age dating (22–25 mm/year); and groundwater modeling (11–26 mm/year). The flownet computational and modeling methods provided better estimates for aerial recharge than the other methods. Based on groundwater modeling, a final estimate for recharge (from precipitation) on the order of 15–20 mm/year is believed to be realistic, assuming that part of the recharge water transpires from the water table by deep-rooted vegetation. This recharge estimate (2.7–3.6% of the annual precipitation of 555 mm/year) compares well with the results of other researchers. The advantages/disadvantages of each recharge method in terms of ease of application, accuracy, and costs are discussed. The groundwater model was also used to quantify the total recharge of the Nyamandhlovu aquifer system (20?×?106–25?×?106 m3/year). Groundwater abstractions exceeding 17?×?106 m3/year could cause ecological damage, affecting, for instance, the deep-rooted vegetation in the area.  相似文献   

16.
A transient finite difference groundwater flow model has been calibrated for the Nasia sub-catchment of the White Volta Basin. This model has been validated through a stochastic parameter randomization process and used to evaluate the impacts of groundwater abstraction scenarios on resource sustainability in the basin. A total of 1500 equally likely model realizations of the same terrain based on 1500 equally likely combinations of the data of the key aquifer input parameters were calibrated and used for the scenario analysis. This was done to evaluate model non-uniqueness arising from uncertainties in the key aquifer parameters especially hydraulic conductivity and recharge by comparing the realizations and statistically determining the degree to which they differ from each other. Parameter standard deviations, computed from the calibrated data of the key parameters of hydraulic conductivity and recharge, were used as a yardstick for evaluating model non-uniqueness. All model realizations suggest horizontal hydraulic conductivity estimates in the range of 0.03–78.4 m/day, although over 70 % of the area has values in the range of 0.03–14 m/day. Low standard deviations of the horizontal hydraulic conductivity estimates from the 1500 solutions suggest that this range adequately reflects the properties of the material in the terrain. Lateral groundwater inflows and outflows appear to constitute significant components of the groundwater budgets in the terrain, although estimated direct vertical recharge from precipitation amounts to about 7 % of annual precipitation. High potential for groundwater development has been suggested in the simulations, corroborating earlier estimates of groundwater recharge. Simulation of groundwater abstraction scenarios suggests that the domain can sustain abstraction rates of up to 200 % of the current estimated abstraction rates of 12,960 m3/day under the current recharge rates. Decreasing groundwater recharge by 10 % over a 20-year period will not significantly alter the results of this abstraction scenario. However, increasing abstraction rates by 300 % over the period with decreasing recharge by 10 % will lead to drastic drawdowns in the hydraulic head over the entire terrain by up to 6 m and could cause reversals of flow in most parts of the terrain.  相似文献   

17.
Groundwater recharge was investigated in the most extensive sand and gravel aquifer (area of approximately 200 km2) in the Republic of Ireland as part of a wider study seeking to derive recharge estimates using aquifer vulnerability mapping. The proportion of effective rainfall (total rainfall minus actual evapotranspiration) that leads to recharge is known as the recharge coefficient. The recharge investigation involved a variety of approaches, including soil moisture budgeting, well hydrograph analysis, numerical modelling and a catchment water balance. The adoption of multiple techniques provided insights on recharge and also on aquifer properties. Comparison of two soil moisture budgeting approaches (FAO Penman-Monteith with Penman-Grindley) showed how variations in the effective rainfall values from these methods influence groundwater levels simulated in a numerical groundwater model. The catchment water balance estimated the recharge coefficient to be between 81 and 85%, which is considered a reasonable range for this aquifer, where overland flow is rarely observed. The well hydrograph analysis, using a previous estimate of specific yield (0.13), gave recharge coefficients in the range of 40–80%, considered low for this aquifer: a revised specific yield of 0.19 resulted in a more reasonable range of recharge coefficients of between 70 and 100%.  相似文献   

18.
To explore the causes of the ecological environment deterioration of lakes in the Inner Mongolia Plateau, this study took a typical inland lake Daihai as an example, and investigated the groundwater recharge in the process of lake shrinkage and eutrophication. Using the radon isotope (222Rn) as the main means of investigation, the 222Rn mass balance equation was established to evaluate the groundwater recharge in Daihai. The spatial variability of 222Rn activity in lake water and groundwater, the contribution of groundwater recharge to lake water balance and its effect on nitrogen and phosphorus pollution in lake water were discussed. The analysis showed that, mainly controlled by the fault structure, the activity of 222Rn in groundwater north and south of Daihai is higher than that in the east and west, and the difference in lithology and hydraulic gradient may also be the influencing factors of this phenomenon. The 222Rn activity of the middle and southeast of the underlying lake is greater, indicating that the 222Rn flux of groundwater inflow is higher, and the runoff intensity is greater, which is the main groundwater recharge area for the lake. The estimated groundwater recharge in 2021 was 3 017×104 m3, which was 57% of the total recharge to the lake, or 1.6 times and 8.1 times that of precipitation and surface runoff. The TN and TP contents in Daihai have been rising continuously, and the average TN and TP concentrations in the lake water in 2021 were 4.21 mg·L?1 and 0.12 mg·L?1, respectively. The TN and TP contents entering the lake with groundwater recharge were 6.8 times and 8.7 times above those of runoff, accounting for 87% and 90% of the total input, respectively. The calculation results showed that groundwater is not only the main source of recharge for Daihai, but also the main source of exogenous nutrients. In recent years, the pressurized exploitation of groundwater in the basin is beneficial in increasing the groundwater recharge to the lake, reducing the water balance difference of the lake, and slowing down the shrinking degree of the lake surface. However, under the action of high evaporation, nitrogen and phosphorus brought by groundwater recharge would become more concentrated in the lake, leading to a continuous increase in the content of nutrients and degree of eutrophication. Therefore, the impact of changes in regional groundwater quantity and quality on Daihai is an important issue that needs further assessment.  相似文献   

19.
Groundwater flow fields in aquifers are often determined by water level data measured in monitoring wells. The flow field can be further refined by mass balance simulations, especially when groundwater level data is limited. The mass balance simulation is based on the principle of mass conservation and relies on water quality data in the same aquifer. The approach is applied to the Luohe aquifer in the Binchang area, China. The water-rock interactions and the hydrogeochemical evolution were studied along four typical flow paths. The study indicates that groundwater in the Luohe formation flows from the southern border to the interior of the Ordos Basin. The southern border, approximately 1,400 km2, is a recharge zone, where the Luohe formation outcrops. The total dissolved solids of the groundwater in the southern boarder are less than 1 g/l, and the hydrochemistry type is HCO3–Na. This new finding refines the flow field of the water-bearing formation, and an additional 1,400 km2 is included in the water resource planning of the area.  相似文献   

20.
Groundwater recharge by natural replenishment for the unconsolidated alluvial aquifer in Wadi Al-Yammaniyah is estimated on a daily basis instead of the conventional monthly basis The study reveals that during the two-year period (1978 and 1979), the estimated recharge in the area is about 40% of the total average annual rainfall of 155 mm Subsurface underflow estimated at 36×10−6 m3/yr from the Wadi Al-Yammaniyah aquifer occurs in the vicinity of Wadi Ash-Shamiyah A comparison of the recharge and extracted volumes of water from the aquifer indicates that there is a net increase of 10 million m3 and 38 million m3 of water in the storage for 1978 and 1979, respectively  相似文献   

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