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1.
Direct groundwater regulation (e.g. registration of abstraction points, permits and concessions) has been much advocated world-wide; however, few successful cases have been reported. The development of groundwater use in Minqin County, Gansu Province, China, is described, with analyses of the situation before and after the implementation of direct groundwater regulation measures in 2007. Based on a survey carried out in 2010, it is argued that the regulation measures, which were part of a broader water-policy reform, were successfully implemented due to their integration with pre-existing collective groundwater institutions. In addition to the regulation measures—the closure of wells and per capita water use restriction—all villages had to form water users’ associations (WUAs) which were assigned to implement the new regulations. These WUAs were found to have the same structure as the existing collective groundwater institutions. Through the water-policy reform, the function of the pre-existing groundwater institutions was transformed from managing “water exploitation” to managing “water conservation”.  相似文献   

2.
Seawater intrusion is one of the most serious environmental problems in many coastal regions all over the world. Mixing a small quantity of seawater with groundwater makes it unsuitable for use and can result in abandonment of aquifers. Therefore, seawater intrusion should be prevented or at least controlled to protect groundwater resources. This paper presents development and application of a simulation‐optimization model to control seawater intrusion in coastal aquifers using different management scenarios; abstraction of brackish water, recharge of freshwater, and combination of abstraction and recharge. The model is based on the integration of a genetic algorithm optimisation technique and a coupled transient density‐dependent finite element model. The objectives of the management scenarios include determination of the optimal depth, location and abstraction/recharge rates for the wells to minimize the total costs for construction and operation as well as salt concentrations in the aquifer. The developed model is applied to analyze the control of seawater intrusion in a hypothetical confined coastal aquifer. The efficiencies of the three management scenarios are examined and compared. The results show that combination of abstraction and recharge wells is significantly better than using abstraction wells or recharge wells alone as it gives the least cost and least salt concentration in the aquifer. The results from this study would be useful in designing the system of abstraction/recharge wells to control seawater intrusion in coastal aquifers and can be applied in areas where there is a risk of seawater intrusion. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

3.
This study approach seeks to characterize the hydraulic interactions between the Nile and the Quaternary aquifer via riverbank filtration (RBF) in Abu Tieg area, Assuit Governorate. The substantial removal/reduction of the most problematic substances during percolation of Nile water into abstraction wells was investigated using physico-chemical and biological indicators. Four sites with 11 municipal wells (20–750 m from the Nile) tapping the alluvial aquifer that is fed by the riverbank infiltrate were monitored. Bank-filtrated water was compared with those of the Nile and groundwater. Results showed that infiltrated Nile water ratio into the wells ranged from 39 to 80% reflecting the effect of distance from the Nile. Removal efficiency of total algal, total and faecal coliforms in bank-filtered water was 99.9%, while turbidity removal ranged from 93 to 98%. Fe, Mn and Zn in the bank-filtered water were relatively higher than those in the Nile, but were still under the allowable standards except those of Mn. LSI and WQI for the bank-filtered water indicated that the water was ranked as non-corrosive and of excellent quality. Comparison of physico-chemical and microbiological characteristics of the bank-filtered water with those of the Nile and groundwater showed the high efficiency of RBF as a treatment technology with minimal cost compared to conventional methods.  相似文献   

4.
地下水是西北内陆河流域干旱半干旱地区重要的供水水源、生态因子和环境因子。当前缺乏针对西北干旱半干旱地区特点的地下水水量和水位双控管理指标确定方法研究,无法为西北地区开展流域水资源管理生态保护提供技术支撑。本研究基于地下水可持续利用和生态保护的原则,提出了一套确定西北地区地下水水量-水位双控指标的技术方案。采用“以位定量”的思路,依据指标监测井代表的不同地下水功能区的地下水管理水位,确定水位指标区间值;将通过天然植被排泄的地下水量作为不可袭夺的排泄项,以数值模拟方法预报求解满足水位指标约束的地下水开采量,计算水量指标区间值。以民勤盆地为研究区开展示例研究,依据技术方案计算得到水位指标的下限阈值为埋深5.00～49.37 m,上限阈值为埋深0.00～5.00 m,水量指标上限为6 000×104 m3/a,下限为10 000×104 m3/a。采用2012—2016年区内实际开采量和监测水位变化趋势进行验证,当开采量在水量指标区间内运行时,水位也基本在水位指标区间内变化。该技术方法可以为西北地区开展双控管理提供一定的技术支撑。  相似文献   

5.
Globally, aquifers are suffering from large abstractions resulting in groundwater level declines. These declines can be caused by excessive abstraction for drinking water, irrigation purposes or industrial use. Basaltic aquifers also face these conflicts. A large flood basalt area (1.1?×?105 km2) can be found in the Northwest of the USA. This Columbia River Basalt Group (CRBG) consists of a thick series of basalt flows of Miocene age. The two major hydrogeological units (Wanapum and Grand Ronde formations) are widely used for water abstraction. The mean decline over recent decades has been 0.6 m year?1. At present day, abstraction wells are drying up, and base flow of rivers is reduced. At the eastern part of CRBG, the Moscow sub-basin on the Idaho/Washington State border can be found. Although a thick poorly permeable clay layer exists on top of the basalt aquifer, groundwater level dynamics suggest that groundwater recharge occurs at certain locations. A set of wells and springs has been monitored bi-weekly for 9 months for δ18O and δ2H. Large isotopic fluctuations and d-excess values close to the meteoric water line in some wells are indicating that recharge occurs at the granite/basalt interface through lateral flow paths in and below the clay. A soil moisture routing (SMR) model showed that most recharge occurs on the granitic mountains. The basaltic aquifer receives recharge from these sedimentary zones around the granite/basalt interface. The identification of these types of areas is of major importance for future managed-aquifer recharge solutions to solve problems of groundwater depletion.  相似文献   

6.
Riverbank filtration (RBF) is an efficient and low-cost natural alternative technology for water supply application in which surface water contaminants are removed or degraded as the infiltrating water moves from the river to the pumping wells. In this study, a full-scale RBF site consisting of three vertical wells installed 50 m from Nile bank was investigated. The RBF systems are particularly well suited for providing better water quality than withdrawal directly from the Nile River to produce drinking water for New Aswan city. The study is carried out by taking samples over 1 year from riverbank filtrates wells, Nile River (as induced surface water), and some production wells were collected and analyzed. Physicochemical and microbiological measurements such as turbidity, dissolved oxygen, total suspended solids, total organic carbon, total dissolved solids, electrical conductivity, pH, Fe, Mn, NH3, NO2, NO3, PO4, Ca, Mg, Na, K, HCO3, SO4, Cl, total bacteria, and total coliform were carried out. The results of bank filtrate were compared with those of the natural groundwater and previous reported Nile water. Chemical and bacterial quality parameters of RBF are under the allowable limits for drinking water. Moreover, bank filtration is simultaneously improved the ambient groundwater and cleaned Nile water in the studied area. Result of this full-scale RBF plant showed the effectiveness of riverbank filtration as a proven treatment technique in Nile Valley with a fraction of cost comparing to conventional surface treatment plants.  相似文献   

7.
Extracted groundwater, 90% of which is used for irrigated agriculture, is central to the socio-economic development of India. A lack of regulation or implementation of regulations, alongside unrecorded extraction, often leads to over exploitation of large-scale common-pool resources like groundwater. Inevitably, management of groundwater extraction (draft) for irrigation is critical for sustainability of aquifers and the society at large. However, existing assessments of groundwater draft, which are mostly available at large spatial scales, are inadequate for managing groundwater resources that are primarily exploited by stakeholders at much finer scales. This study presents an estimate, projection and analysis of fine-scale groundwater draft in the Seonath-Kharun interfluve of central India. Using field surveys of instantaneous discharge from irrigation wells and boreholes, annual groundwater draft for irrigation in this area is estimated to be 212 × 106 m3, most of which (89%) is withdrawn during non-monsoon season. However, the density of wells/boreholes, and consequent extraction of groundwater, is controlled by the existing hydrogeological conditions. Based on trends in the number of abstraction structures (1982–2011), groundwater draft for the year 2020 is projected to be approximately 307 × 106 m3; hence, groundwater draft for irrigation in the study area is predicted to increase by ～44% within a span of 8 years. Central to the work presented here is the approach for estimation and prediction of groundwater draft at finer scales, which can be extended to critical groundwater zones of the country.  相似文献   

8.
Assessment of possible sources that control the groundwater quality was carried out in the Cauvery deltaic region, India, since domestic and agricultural water requirements are largely met by groundwater abstraction. Major ion and bromide contents are high in groundwater in the coastal wells. Spatial and vertical distributions of ions reveal that the shallow wells and wells in coastal parts have high chloride, nitrate, ammonium and phosphate. Groundwater quality assessment was carried out using the prescribed limits of World Health Organization and Bureau of Indian Standards which indicates that 55 % of samples are not fit for drinking. Integrated suitability map for drinking was created based on the concept that if the water sample exceeds any one of the standards by World Health Organization or Bureau of Indian Standards, the well is not fit for drinking. Groundwater quality for agricultural activities was assessed using electrical conductivity, sodium adsorption ratio, residual sodium carbonate, United States salinity laboratory diagram and Food and Agricultural Organization methods. According to Food and Agricultural Organization, 84 % of samples are classified as low sodium water and are suitable for all crops and soils. It was found that the water quality in this area is affected by improper disposal of waste, sewage/drainage canals near the wells, irrigation return flow, application of agrochemicals and saline water intrusion in the coastal region. Further, integrated suitability map produced in this study will be useful for future groundwater development and planning in this area. The suitability map needs to be updated periodically for proper management plan to preserve the groundwater resource in this region.  相似文献   

9.
《Applied Geochemistry》2006,21(1):83-97
Groundwater in the Gwelup groundwater management area in Perth, Western Australia has been enriched in As due to the exposure of pyritic sediments caused by reduced rainfall, increased groundwater abstraction for irrigation and water supply, and prolonged dewatering carried out during urban construction activities. Groundwater near the watertable in a 25–60 m thick unconfined sandy aquifer has become acidic and has affected shallow wells used for garden irrigation. Arsenic concentrations up to 7000 μg/L were measured in shallow groundwater, triggering concerns about possible health effects if residents were to use water from household wells as a drinking water source. Deep production wells used for public water supply are not affected by acidity, but trends of progressively increasing concentrations of Fe, SO4 and Ca over a 30-a period indicate that pyrite oxidation products extend to the base of the unconfined aquifer. Falling Eh values are triggering the release of As from the reduction of Fe(III) oxyhydroxide minerals near the base of the unconfined aquifer, increasing the risk that groundwater used as a drinking water source will also become contaminated with high concentrations of As.  相似文献   

10.
Overexploitation of groundwater resources in Sana’a Basin, Yemen, is causing severe water shortages associated water quality degradation. Groundwater abstraction is five times higher than natural recharge and the water-level decline is about 4–8 m/year. About 90 % of the groundwater resource is used for agricultural activities. The situation is further aggravated by the absence of a proper water-management approach for the Basin. Water scarcity in the Wadi As-Ssirr catchment, the study area, is the most severe and this area has the highest well density (average 6.8 wells/km2) compared with other wadi catchments. A local scheme of groundwater abstraction redistribution is proposed, involving the retirement of a substantial number of wells. The scheme encourages participation of the local community via collective actions to reduce the groundwater overexploitation, and ultimately leads to a locally acceptable, manageable groundwater abstraction pattern. The proposed method suggests using 587 wells rather than 1,359, thus reducing the well density to 2.9 wells/km2. Three scenarios are suggested, involving different reductions to the well yields and/or the number of pumping hours for both dry and wet seasons. The third scenario is selected as a first trial for the communities to action; the resulting predicted reduction, by 2,371,999 m3, is about 6 % of the estimated annual demand. Initially, the groundwater abstraction volume should not be changed significantly until there are protective measures in place, such as improved irrigation efficiency, with the aim of increasing the income of farmers and reducing water use.  相似文献   

11.
Groundwater accounts for about half of the water use for irrigation in India.The fluctuation pattern of the groundwater level is examined by observing rainfall replenishment and monitoring wells.The southern part of Rajasthan has experienced abrupt changes in rainfall and has been highly dependent on groundwater over decades.This study presents the impact of over-dependence on groundwater usage for irrigation and other purposes,spatially and temporally.Hence,the objective of this study is to examine the groundwater level trend by using statistical analysis and geospatial technique.Rainfall factor was also studied in groundwater level fluctuation during 2009-2019.To analyze the influence of each well during recharge or withdrawal of groundwater,thiessien polygonswere generated from them.In the Jakham River basin,75 wells have been identified for water level trend study using the Mann-Kendall statistical test.The statistics of trend analysis show that 15%wells are experiencing water level decline in pre-monsoon,while very low percentage of wells have such trend during post-monsoon season.The average rate of water level decline is 0.245 m/a in pre-monsoon and 0.05 m/a in post-monsoon.The aquifer recharge potential is also decreasing by year.it is expected that such type of studies will help the policy makers to adopt advanced management practices to ensure sustainable groundwater resource management.  相似文献   

12.
The groundwater reserves in Kharga Oases have been studied for the long-term socioeconomic development in the area. The Nubian Sandstone, which consists of a thick sequence of coarse clastic sediments of sandstone, sandy clay interbedded with shale, and clay beds, forms a complex aquifer system. The Nubian Aquifer has been providing water to artesian wells and springs in the Kharga Oases for several thousand years. Groundwater in the Kharga Oases is withdrawn from springs and shallow and deep artesian wells Nearly all the wells originally flowed, but with the exploitation of ground-water from deep wells for irrigation beginning about 1959. the natural flows declined as more and more closely spaced deep wells were drilled By 1975 many deep wells had ceased to flow The water demand in the area has been met by pumping both shallow and deep wells The total annual extraction from deep wells has fluctuated over the year, however, the annual withdrawal from deep wells has exceeded extraction from shallow wells About 17 billion m3 of water was withdrawn from the combination of shallow and deep wells during the period 1960–1980 The Nubian complex aquifer in the Kharga Oases has a very large groundwater potential that could be exploited and beneficially used for a long-term agricultural development in the area, provided proper well spacing and management are implemented Other major environmental considerations for which precise hydrogeologic data are needed include
  1. Determination of the long-term yield available from properly constructed and producing artesian wells that will support a planned migration of population from the overcrowded Nile delta and flood plain areas
  2. Development of an effective management program and adequate staff to maintain groundwater production over an extended period of years
  3. The impact on climate caused by extensive irrigation in the oases of the Western Desert of Egypt
  4. Protection against water logging of soils from irrigation practices
  5. Protection against salinization of soils from irrigation practices
  6. Development of effective surface and subsurface drainage practices
  7. The impact of farming and pest control practices on the shallow groundwater of the oases
  8. Determination of the long-term development of the artesian water on the quality of the water from the aquiter systems in the Western Desert
This paper addresses items 1, 2 and 8.  相似文献   

13.
The continuous and large-scale abstraction of groundwater has created a groundwater depletion problem in several parts of the Punjab state including Bist Doab, the interfluve region of Beas and Satluj rivers. In the present study, a few important parameters, viz. water level, stable isotope, EC, temperature, groundwater age, that can be used to fingerprint the over-exploitation of groundwater have been examined. It has been observed that with the increase in over-exploitation, the yield of shallow aquifer is progressively getting reduced and as a result forcing the farmers to sink their wells to deeper depths. With abstraction of deeper aquifer, the storage of old groundwater at the deeper aquifer is declining and getting replaced by induced accelerated inflow of young water from the recharge zone and the overlying shallow aquifer. The signatures of the modern water have been observed in the data analyzed for isotopic, hydro-chemical facies, electrical conductivity and temperature of water from deeper aquifer. The study has identified the usefulness of these parameters for identifying groundwater over-exploitation in the region. Depleting water resource may stagnate the economic progress of the region. The paper provides suitable water resource management strategies to be adopted to improve the sustainability of water resources and economic growth in the region.  相似文献   

14.
The deeper groundwater (depending on definition) of the Bengal basin (Ganges-Brahmaputra delta) has long been considered as an alternate, safe drinking-water source in areas with As-enrichment in near-surface groundwater. The present study provides the first collective discussion on extent and controls of elevated As in deeper groundwater of a regional study area in the western part of the Bengal basin. Deeper groundwater is defined here as non-brackish, potable (Cl− ? 250 mg/L) groundwater available at the maximum accessed depth (∼80-300 m). The extent of elevated As in deeper groundwater in the study area seems to be largely controlled by the aquifer-aquitard framework. Arsenic-enriched deeper groundwater is mostly encountered north of 22.75°N latitude, where an unconfined to semi-confined aquifer consisting of Holocene- to early Neogene-age gray sand dominates the hydrostratigraphy to 300 m depth below land surface. Aquifer sediments are not abnormally enriched in As at any depth, but sediment and water chemistry are conducive to As mobilization in both shallow and deeper parts of the aquifer(s). The biogeochemical triggers are influenced by complex redox disequilibria. Results of numerical modeling and profiles of environmental tracers at a local-scale study site suggest that deeper groundwater abstraction can draw As-enriched water to 150 m depth within a few decades, synchronous with the advent of wide-scale irrigational pumping in West Bengal (India).  相似文献   

15.
Groundwater resources in semi-arid areas and especially in the Mediterranean face a growing demand for irrigated agriculture and, to a lesser extent, for domestic uses. Consequently, groundwater reserves are affected and water-table drops are widely observed. This leads to strong constraints on groundwater access for farmers, while managers worry about the future evolution of the water resources. A common problem for building proper groundwater management plans is the difficulty in assessing individual groundwater withdrawals at regional scale. Predicting future trends of these groundwater withdrawals is even more challenging. The basic question is how to assess the water budget variables and their evolution when they are deeply linked to human activities, themselves driven by countless factors (access to natural resources, public policies, market, etc.). This study provides some possible answers by focusing on the assessment of groundwater withdrawals for irrigated agriculture at three sites in North Africa (Morocco, Tunisia and Algeria). Efforts were made to understand the different features that influence irrigation practices, and an adaptive user-oriented methodology was used to monitor groundwater withdrawals. For each site, different key factors affecting the regional groundwater abstraction and its past evolution were identified by involving farmers’ knowledge. Factors such as farmer access to land and groundwater or development of public infrastructures (electrical distribution network) are crucial to decode the results of well inventories and assess the regional groundwater abstraction and its future trend. This leads one to look with caution at the number of wells cited in the literature, which could be oversimplified.  相似文献   

16.
Groundwater pumped from the semi-confined Complex Terminal (CT) aquifer is an important production factor in irrigated oases agriculture in southern Tunisia. A rise in the groundwater salinity has been observed as a consequence of increasing abstraction from the aquifer during the last few decades. All sources of contamination were investigated using hydrochemical data available from the 1990s. Water samples were taken from wells tapping both the CT and the shallow aquifers and analyzed with regard to chemistry tracers. Hydrochemical and water quality data obtained through a sampling period (December 2010) and analysis program indicate that nitrate pollution can be a serious problem affecting groundwater due to the use of nitrogen (N) fertilizers–pesticides in agriculture. The concentration of nitrate in an groundwater-irrigated area in Gafsa oases basin was studied, where abstraction from an unconfined CT aquifer has increased threefold over 25 years to 34 million m3/year; groundwater levels are falling at up to 0.7 m/year; and groundwater is increasingly mineralised (TDS increase from 500 to 4,000 mg/L), with nitrate concentrations ranging from 16 to 320 mg/L.  相似文献   

17.
A 'first pass' groundwater management policy has been developed for use by non-governmental organisations (NGOs) in Afghanistan, designed to prevent derogation of existing traditional water sources, aquifer over-abstraction and chemical deterioration of soil and groundwater quality. Key elements include (1) continuing promotion of groundwater as a drinking water source, (2) a presumption against use of motorised pumps to abstract groundwater for irrigation unless other options (surface water, qanats) are not available, (3) the use of groundwater for irrigation as a temporary alternative to surface water (i.e. a strategy for drought survival) rather than as a long-term development policy, (4) limiting groundwater abstraction to a long-term average of 1 l s–1 km–2, (5) siting irrigation wells at least 500 m from other groundwater sources and (6) analysing irrigation groundwater for electrical conductivity, sodium absorption ratio, boron and residual sodium carbonate alkalinity. Analyses of these parameters indicate that groundwater from some areas is of dubious suitability for irrigation. In some villages and towns, groundwater contains elevated nitrate and faecal bacteria concentrations, probably derived from latrines, sewage or animal wastes. Electronic Publication  相似文献   

18.
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   

19.

Within the Ararat Valley (Armenia), a continuously growing water demand (for irrigation and fish farming) and a simultaneous decline in groundwater recharge (due to climate change) result in increasing stress on the local groundwater resources. This detrimental development is reflected by groundwater-level drops and an associated reduction of the area with artesian conditions in the valley centre. This situation calls for increasing efforts aimed at more sustainable water resources management. The aim of this baseline study was the collection of data that allows for study on the origin and age distribution of the Ararat Valley groundwater based on environmental tracers, namely stable (δ2H, δ18O) and radioactive (35S, 3H) isotopes, as well as physical-chemical indicators. The results show that the Ararat Valley receives modern recharge, despite its (semi-)arid climate. While subannual groundwater residence times could be disproved (35S), the detected 3H pattern suggests groundwater ages of several decades, with the oldest waters being recharged around 60 years ago. The differing groundwater ages are reflected by varying scatter of stable isotope and hydrochemical signatures. The presence of young groundwater (i.e., younger that the 1970s), some containing nitrate, indicates groundwater vulnerability and underscores the importance of increased efforts to achieve sustainable management of this natural resource. Since stable isotope signatures indicate the recharge areas to be located in the mountains surrounding the valley, these efforts must not be limited to the central part of the valley where most of the abstraction wells are located.

  相似文献   

20.
This paper presents an overview of the evolution of the Nile deep‐sea turbidite system during the last 200 kyr, over a series of glacial to interglacial cycles. Six individual deep‐sea fans were identified from an extensive field data set. Each fan comprises a canyon, channel system and terminal lobes. Two of these fan systems were possibly active at the same time, at least during some periods. Large‐scale slope failures destroyed channel segments and caused the formation of new submarine fan systems. These slope failures thus played an important role in the overall evolution of the turbidite system. During the last glacial maximum (ca 25 to 14·8 ka) the central and eastern parts of the Nile deep‐sea turbidite system were relatively inactive. This inactivity corresponds to a lowstand in sea‐level, and a period of arid climate and relatively low sediment discharge from the Nile fluvial system. Rapid accumulation of fluvial flood‐derived deposits occurred across the shallower part of the submarine delta during sea‐level rise between ca 14·8 and 5 ka. The most recent deep‐sea channel–lobe system was very active during this period of rising sea‐level, which is also associated with a wetter continental climate and increased sediment and water discharge from the Nile. Increased sediment deposition in shallower water areas led to occasional large‐scale slope failure. The Nile deep‐sea turbidite system was largely inactive after ca 5 ka. This widespread inactivity is due to retreat of the coastline away from the continental shelf break, and to a more arid continental climate and reduced discharge of sediment from the Nile. The Nile deep‐sea turbidite system may be more active during periods of rising and high sea‐level associated with wetter climates, than during lowstands, and may rapidly become largely inactive during highstands in sea‐level coupled with arid periods. These acute responses to climate change have produced sedimentary/stratigraphic features that diverge from traditional sequence models in their nature and timing. This large‐scale sedimentary system responded to monsoon‐driven climate change and sea‐level change in a system‐wide and contemporaneous manner.  相似文献   

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