Investigation of land subsidence due to groundwater withdraw in Rafsanjan plain using GIS software

Nowadays, the purpose of predicting land subsidence is to manage the optimum usage of groundwater, which is considered according to irregular use of groundwater. Digging deep and semi-deep wells and continuous drought, mainly in wasteland and semi-wasteland zone in recent years causes the land subsidence in Rafsanjan plain. The Rafsanjan basin is located in the nearly central part of Iran in the Kerman province, with a general elevation between 1,400–1,500 m above sea level. In this research, first, the deep and semi-deep wells were investigated and groundwater table data were colleted. Second, these informations were analyzed and corrected. These data were used to create great bank of information data, to manage and program the geographic information system (GIS) software. Then by investigation of an existing land subsidence data, which were collected by GPS in August 1998 and April 1999, by the GIS software, the results show that discharging of groundwater is the main factor of the land subsidence in Rafsanjan zone. Therefore, the critical land subsidence zone of the Rafsanjan plain was determined, and precaution and recommendations are presented.     

Simulation of land subsidence using finite element method: Rafsanjan plain case study

Land subsidence caused by the excessive use of groundwater resources has caused serious damage to Rafsanjan area. In this study, using finite element method, a 2D plain strain simulation of land subsidence has been conducted. A linear elastic constitutive law has been used for the simulation of the soil material skeleton. Actual water level during the analysis period has been modeled via specifying nodal water pressure at piezometer wells situation. The solution procedure consists of two parts. First, an initial static analysis is carried out in order to find initial steady-state solution for the pore pressure and stress distribution. Then, the above solution is used as initial condition for dynamic computation of consolidation equations during pumpage period. Tectonic effect has been considered as a rigid body motion. Numerical results showed that if the rate of pumpage remains constant in the future, settlement due to water withdrawal near Rafsanjan city will reach up to 110 cm by the year 2022.     

Potential impacts of climate change on groundwater levels on the Kerdi-Shirazi plain,Iran

It is important to predict how groundwater levels in an aquifer will respond to various climate change scenarios to effectively plan for how groundwater resources will be used in the future. Due to the overuse of groundwater resources and the multi-year drought in the Kerdi-Shirazi plain in Iran, some land subsidence and a drop in groundwater levels has taken place, and without active management, further degradation of the groundwater resource is possible under predicted future climate change scenarios in the country. To determine the potential impacts of climate change on groundwater levels in the region, the groundwater model GMS was coupled with the atmospheric circulation model HADCM3 using scenarios A1B, A2 and B1 for the period 2016–2030. The results of the climate modelling suggest that the Kerdi-Shirazi plain will experience an increase in minimum temperature and maximum temperature of, respectively, between 0.03 and 0.47, and 0.32–0.45 °C for this time period. The results of the groundwater modelling suggest that water levels on the Kerdi-Shirazi plain will continue to decline over the forecast period with decreases of 34.51, 36.57 and 33.58 m being predicted, respectively, for climate scenarios A1B, A2 and B1. Consequently, groundwater resources in the Kerdi-Shirazi plain will urgently need active management to minimize the effects of ongoing water level decline and to prevent saltwater intrusion and desertification in the region.     

Intervention scenarios to manage seawater intrusion in a coastal agricultural area in Oman

The Batinah coastal plain in northern Oman has experienced a severe deterioration of groundwater quality due to seawater intrusion as a result of excessive groundwater abstraction for agricultural irrigation. Upgrading all farms to fully automated irrigation technology based on soil moisture sensors may significantly reduce the water demand and lead to recovering groundwater levels. This study compares the effects of smart irrigation technology, recharge dams, and a combination of both on seawater intrusion in the coastal aquifer of the Batinah. A groundwater flow and transport model is used to simulate the effect of reduced pumping rates on seawater intrusion for various intervention scenarios over a simulation period of 30 years, and an economic analysis based on cost-benefit analysis is conducted to estimate the potential benefits. Results indicate that a combination of smart irrigation and recharge dams may prevent further deterioration of groundwater quality over the next 30 years. In conjunction with increased efficiency, this combination also generates the highest gross profit. This outcome shows that the problem of seawater intrusion needs to be tackled by a comprehensive, integrated intervention strategy.     

A GIS-index integration approach to groundwater suitability zoning for irrigation purposes

In recent decades, the high population growth has increased the demand for agricultural lands and products. Groundwater offers reliability and flexibility in access to water for irrigation purposes, especially in arid and semi-arid areas, such as Amol-Babol Plain, Iran. However, the quality and quantity of groundwater may not be suitable for irrigation purposes in all areas due to urbanizations, and intensive agricultural and industrial activities. Groundwater suitability zoning for irrigation purposes could be useful to improve water resources and land use planning, mostly in areas with water scarcity. Therefore, a GIS-based indices method is proposed to assess suitable zones for agricultural activities, integrating the irrigation water quality (IWQ) index and hydrogeological factors. IWQ index was utilized to assess groundwater quality based on salinity hazard, infiltration hazard, specific ions, and trace elements hazards, and miscellaneous effects such as pH, bicarbonate, and nitrate. The potential of the aquifer for irrigation water abstraction was investigated using hydrogeological surveys such as slope angle of the plain, hydraulic conductivity, and aquifer thickness. The groundwater suitability index classified most of the study area (more than 90 %) as “excellent” or “good” suitability zones for irrigation purposes. A limited area of around 5.6 % of the total area has moderate suitability for irrigation purposes due to the Caspian Seawater intrusion and the presence of fossil saline water. The proposed methodology provides useful information in order to allow irrigation management to prevent water and soil deterioration.     

Hydrogeologic assessment of escalating groundwater exploitation in the Indus Basin, Pakistan

Groundwater development has contributed significantly to food security and reduction in poverty in Pakistan. Due to rapid population growth there has been a dramatic increase in the intensity of groundwater exploitation leading to declining water tables and deteriorating groundwater quality. In such prevailing conditions, the hydrogeological appraisal of escalating groundwater exploitation has become of paramount importance. Keeping this in view, a surface water–groundwater quantity and quality model was developed to assess future groundwater trends in the Rechna Doab (RD), a sub-catchment of the Indus River Basin. Scenario analysis shows that if dry conditions persist, there will be an overall decline in groundwater levels of around 10 m for the whole of RD during the next 25 years. The lower parts of RD with limited surface water supplies will undergo the highest decline in groundwater levels (10 to 20 m), which will make groundwater pumping very expensive for farmers. There is a high risk of groundwater salinization due to vertical upconing and lateral movement of highly saline groundwater into the fresh shallow aquifers in the upper parts of RD. If groundwater pumping is allowed to increase at the current rate, there will be an overall decline in groundwater salinity for the lower and middle parts of RD because of enhanced river leakage.     

A study of the interrelation between surface water and groundwater using isotopes and chlorofluorocarbons in Sanjiang plain,Northeast China

Surface water and groundwater are the main water resources used for drinking and production. Assessments of the relationship between surface water and groundwater provide information for water resource management in Sanjiang plain, Northeast China. The surface water (river, lake, and wetland) and groundwater were sampled and analyzed for stable isotopic (δD, δ ¹⁸O) composition, tritium, and chlorofluorocarbons concentrations. The local meteoric water line is δD = 7.3δ ¹⁸O–6.7. The tritium (T) and chlorofluorocarbon (CFC) contents in groundwater were analyzed to determine the groundwater ages. Most groundwater were modern water with the ages <50 years. The groundwaters in mountain area and near rivers were younger than in the central plain. The oxygen isotope (δ ¹⁸O) was used to quantify the relationship between surface water and groundwater. The Songhua, Heilongjiang, and Wusuli rivers were gaining rivers, but the shallow groundwater recharged from rivers at the confluence area of rivers. At the confluence of Songhua and Heilongjiang rivers, 88 % of the shallow groundwater recharged from Songhua river. The combination of stable isotopes, tritium, and CFCs was an effectively method to study the groundwater ages and interrelation between surface water and groundwater. Practically, the farmlands near the river and under foot of the mountain could be cultivated, but the farmlands in the central plain should be controlled.     

Analysis of temporal and spatial variations in groundwater nitrate and development of its pollution plume: a case study in Karaj aquifer

Considering the importance of groundwater resources in water-supply demands in arid and semiarid areas such as Iran, it is essential to investigate the risk of groundwater pollution. Nitrate is one of the main pollutants that penetrate into the groundwater from various sources such as chemical fertilizers, pesticides, and domestic and industrial sewage. Unfortunately currently, nitrate contamination of the aquifers is a serious problem in Iran. The Karaj aquifer is not exempted, and the nitrate pollution zone, with concentrations far beyond the permitted limit (50 mg/L), expands fast. In this paper, the long-term groundwater-quality data (from 2000 to 2013) collected from Alborz Province Water and Wastewater Company were analyzed using ArcGIS10 and statistical software, and the spatial and temporal patterns of nitrate pollution in drinking-water wells in the Karaj plain and effective parameters (such as depth to groundwater level, hydraulic gradient, land use, precipitation, and urban, agricultural and industrial wastewater) were investigated. The authors also investigated the status of nitrate concentration variation using the concepts of geostatistics, based on determinations from 62 to 194 surveyed wells with a suitable distribution across the plain. With respect to the relationship between quality parameters, hydrogeological status of the aquifer and land usage, causes of the increase in the concentration of nitrate in the water and its trend were investigated as well. Results revealed that the nitrate levels in the northern portion of the study area were the highest with maximum concentrations of 181.7 mg/L from 2000 to 2013. Based on nitrate concentration distribution maps, the levels of nitrate increased from 2006 onwards to 26–100 mg/L. Unfortunately from 2008 to 2012, a pollution zone with a nitrate water concentration of 101–150 mg/L has been observed and even a concentration of 180 mg/L has been determined. In 2000, the entire aquifer area has been drinkable but with the increase in nitrate concentration, the area with undrinkable water has expanded to 21% in 2003, 24% in 2005, 33% in 2007, 39% in 2009, 43% in 2011 and 44% in 2013. The results of this study could provide valuable information with on the status of nitrate water concentrations in the Karaj plain which demands proper strategies and qualitative approaches in the future.     

Aquifer system incremental linear property and its application on groundwater management

Generally, an aquifer system coupled into a groundwater management model was regarded as a linear system. However, in terms of systems analysis, the aquifer system can be proven to be an incremental linear system rather than a linear system. For example, a confined aquifer system can be decomposed into two parts, one of which is a linear time invariability sub-system and another is a zero-input response. This system does not meet the additivity property of linear system, but satisfies the incremental linear system characteristics. In order to better understand, a case study of water resources management of Huaibei city within semiarid region, north Anhui province of China, is cited. Taking into account the water demand for satisfying the urban development in the next 15 years, three planning target years of water resources are preset as the present (2005), the short term (2010) and the long term (2020), respectively, and four hydrological years (e.g., wet year, mean year, dry year, and extremely dry year) are also defined by the rainfall data of many years. A groundwater management model based on linear programming is established. This model can deal with 12 possible scenarios (3 target years × 4 hydrological years), optimize the strategies of water resources development, integrate various kinds of water sources (e.g., groundwater, surface–water and additional water) and meet the water demand for the urban development of Huaibei city. In accordance with the groundwater management model solutions, the problem of groundwater drawdown funnels (groundwater overextraction funnels) which formed within the Huaibei downtown area for many years and led to some environmental and social issues will be solved over the whole planning period. More importantly, through statistically analyzing the model solutions, the relationships between the groundwater pumping (input signals) and groundwater level recovery (output signals) show up the characteristics of the incremental linear system.     

Groundwater resources assessment for irrigable agricultural lands in the Wadi Araba area, southern Jordan

The main target of this research paper was to the hydrogeological assessment of the groundwater resources to irrigate 600 ha of irrigable agricultural lands, distributed along the Dead Sea–Aqaba Highway in Umm, Methla, Wadi Musa, Qa’ Saideen and Rahma, southern Jordan. Therefore, a comprehensive groundwater study was commenced by drilling eight new wells which can be used to supply irrigable areas with the existing groundwater that would be enriched by the yield of three proposed recharge dams on Wadi Musa, Wadi Abu-Burqa, and Wadi Rahma. The evaluation of the pumping test data of the drilled was carried out using the standard methods of pumping test interpretation. This was based on the available water table measurements at well locations and knowledge of water flow in the general. The sustainable yield of each well was calculated based on the pumping test parameters. The obtained results indicate that pumping out of Beer Mathkor wells should not exceed 1,100 m³/day in the case of continuous pumping and 8,700 m³/day in the case of intermittent pumping. Since the water table did not significantly change with small changes in pumping (it took eightfolds of magnitude increase in pumping from approximately 1,100 to 8,700 m³/day to show a significant drop in the water table equivalent to about 5.5 MCM per year from the aquifer.     

Spatial variation assessment of groundwater quality using multivariate statistical analysis(Case Study: Fasa Plain,Iran)

Groundwater is considered as one of the most important sources for water supply in Iran. The Fasa Plain in Fars Province, Southern Iran is one of the major areas of wheat production using groundwater for irrigation. A large population also uses local groundwater for drinking purposes. Therefore, in this study, this plain was selected to assess the spatial variability of groundwater quality and also to identify main parameters affecting the water quality using multivariate statistical techniques such as Cluster Analysis (CA), Discriminant Analysis (DA), and Principal Component Analysis (PCA). Water quality data was monitored at 22 different wells, for five years (2009-2014) with 10 water quality parameters. By using cluster analysis, the sampling wells were grouped into two clusters with distinct water qualities at different locations. The Lasso Discriminant Analysis (LDA) technique was used to assess the spatial variability of water quality. Based on the results, all of the variables except sodium absorption ratio (SAR) are effective in the LDA model with all variables affording 92.80% correct assignation to discriminate between the clusters from the primary 10 variables. Principal component (PC) analysis and factor analysis reduced the complex data matrix into two main components, accounting for more than 95.93% of the total variance. The first PC contained the parameters of TH, Ca²⁺, and Mg²⁺. Therefore, the first dominant factor was hardness. In the second PC, Cl^-, SAR, and Na⁺ were the dominant parameters, which may indicate salinity. The originally acquired factors illustrate natural (existence of geological formations) and anthropogenic (improper disposal of domestic and agricultural wastes) factors which affect the groundwater quality.     

河北省平原区农田粮食增产与灌溉节水对地下水开采量的影响

河北平原是中国粮食和蔬菜的主要产区之一,也是以地下水作为主要供给水源的地区。近50年来粮食持续大幅增产,驱动区内地下水开采量不断增大。在这一过程中,农田灌溉节水有效地缓解了粮食增产对地下水开采量增加的速率,拓展了在有限的可利用地下水资源条件下粮食增产的发展空间。在1977年之前,每增产10000t小麦和玉米,多年平均地下水实际开采量增加0.14×108m3,1978年以来,每增产10000t小麦和玉米,多年平均实际开采量只增加0.04×108m3。因此,大力发展抗旱节水作物,合理调控农业种植结构,是缓解河北平原农田区地下水超采状况的重要途径。     

A semi-distributed groundwater recharge model for estimating water-table and water-balance variables

A semi-distributed groundwater recharge model is presented, which estimates water-table fluctuation and water-balance variables. The model is expressed by the water-balance concept linking atmospheric and hydrogeological parameters to different water uses (industrial, agricultural, domestic, etc). It was calibrated and validated using 5 years of data collected in the Dogo Plain in Japan. A 3-year dataset, from 2000 to 2002, was used in the calibration, while a 2-year dataset, from 2003 to 2004, was used for the validation. Calibration of the model was achieved by the shuffled complex evolution automatic optimization of model parameters to match simulated results with measured water-table depth. Square roots of relative error (R²) are 0.88 and 0.90 for calibration and validation processes, respectively. Monthly evolution of water storage change was then estimated and the water-table drawdown in different pumping scenarios was simulated. Finally, the groundwater-pumping amount planned by the government for future sustainable groundwater utilization was evaluated. The government-planned groundwater-pumping amount is feasible in most regions while the midstream region should be paid more attention. This study offers a scientific basis to control and prevent depletion of groundwater resources.     

A groundwater flow model for overexploited basaltic aquifer and Bazada formation in India

Recent changes in land use practices, such as increase in orange orchards in central India, has put undue pressure on the groundwater resources. Excess withdrawal from the aquifers has resulted in groundwater table decline. The stage of groundwater development in some watersheds has reached 155.85 %, converting these into overexploited watersheds. In the present research paper, a groundwater flow model has been developed to evaluate the groundwater system in a basaltic terrain with Bazada formation. A conceptual model has been developed and calibrated for steady and transient states and the sensitivity analysis was carried out. Future predictions, for current scenario where present practices are continued and for scenario with 20 % reduction in groundwater draft have been made, to select the best strategy for mitigating the problem. The modeling results show that the decline in groundwater level in basaltic and Bazada unconfined aquifers will result into drying up (water level more than 15 m bgl) of 243 km² area by 2020. To restore the groundwater level, it is simulated that the groundwater draft rate must be reduced by 20 % for next 10 years. It may be achieved by adopting groundwater management strategies, particularly for irrigation sector.     

300年以来太行山前平原地下水补给演化特征与趋势

从近300a来太行山平原典型区地下水入渗补给演化特征、机制和未来50a区域水循环中水分通量演化趋势3个方面，阐明了山前平原地下水补给能力的周期可变性和该区现状资源型缺水的客观性。在此基础上，提出了进一步开展百年尺度水循环演化趋势基础研究的建议。     

Impact of spate irrigation of flood waters on agricultural drought and groundwater recharge: case of Sidi Bouzid plain,Central Tunisia

In Sidi Bouzid plain, rainfall alone is insufficient to satisfy crop water requirements. Within this framework, and in order to improve water resources in the region, the Tunisian State adopted non-conventional water mobilization techniques, among which artificial spate irrigation. The objective of the study is to evaluate the impact of spate irrigation of flood water on the mitigation of agricultural drought and the enhancement of groundwater recharge. Annual and monthly rainfall data as well as flood water volumes were monitored. The study focused on the groundwater drawdown monitoring. Results showed a high flood water contribution to crop water requirements that exceeded rainfall. This water prevented drought in the spate perimeters. The groundwater drawdown was found to fluctuate over time, with an average decreasing rate of 0.4 to 0.5 m/year. Groundwater recharge was found to be highly correlated with flood water contribution through spate irrigation (R ² = 84 %). Out of the spate zone, a high decrease in the groundwater level was noted. The lowest rate of 1 m/year was that of the farthest piezometer from the spate perimeters. This is influenced by the excessive pumping out of the spate zone. In 1980, groundwater flew from the west to the east. In 2015, the flow movement from the east to the center of the plain did not change due to the presence of the spate perimeters. Nevertheless, excessive pumping around sabkhas changed the flow directions at the outlet zone. A variation in groundwater salinity was observed in both space and time. In 1975, salinity was very low. The outlet zone was the most affected where the drawdown reached several meters, causing saltwater intrusion from the surrounding sabkhas.     

江苏苏锡常地区地下水开采出现的问题及对策研究

近年来,江苏苏锡常地区地表水由于遭受严重污染,致使地下水开采量逐年增加;又由于缺乏正确认识和科学管理,造成该地区地下水资源长期超采,从而引发了地面沉降、地裂缝等环境地质问题和地质灾害。本文从可持续发展观点出发,为使地下水资源合理开采和保护同步发展,有针对性地探讨了该地区地下水资源合理开发和保护对策。     

Assessment of groundwater quality and its suitability for domestic and agricultural uses in Low-Isser plain,Boumedres, Algeria

The assessment of the suitability of groundwater for drinking and irrigation uses was carried out in the alluvial plain of Low-Isser in the north of Algeria. The plain covers an area of 533 km² and lies in a Mediterranean sub-humid climate. Groundwater is the main source for domestic uses and agricultural activities in this area. Groundwater samples were collected from 15 wells during dry and wet seasons in 2015, and they were analyzed for major cations and anions and compared with drinking and irrigation specification standards. The comparison of chemical concentration with WHO drinking water standards of 2006 shows that more than 30% of groundwater samples are unsuitable for drinking, and the majority of groundwater samples fell on the hard and very hard categories. Suitability of groundwater for drinking was also evaluated based on the water quality index (WQI). It shows more than 80% of samples have good or permissible water quality for dry and wet seasons. In terms of the irrigation usage, generally, groundwater in the study area is suitable for different uses in both seasons according to SAR, %Na, RSBC, and PI. However, water rock exchange processes and groundwater flow have been responsible for the dominated water type Ca–Mg–Cl.     

贵阳市岩溶地下水水质变化特征浅析

为了解长时间尺度岩溶地下水的水质变化特征,本文以贵阳市中心城区为例,选取1984年和2014年48组原位取样点的丰季水质数据,并结合地下水赋存环境和城市发展特征进行对比分析。结果显示:研究区地下水水质较好,整体有恶化的趋势;1984年仅有9处地下水水质超标,多数超标点为原生背景成因,2014年有14处水质超标,多数超标点为人类活动引起;地下水化学类型在30年间变化较大,近一半取样点地下水由HCO3型变成HCO3·SO4型水,研究区地下水硫酸盐化明显;新老城区地下水水质逐步好转,城乡结合部地带则是地下水污染的高发区,农业区因人类活动强度较低,地下水水质变化相对平缓。建议在岩溶城市的地下水资源开发和地下水环境保护工作中,应综合考虑不同区域的岩溶水文地质条件和人类活动特征,有的放矢的开展评价监测管理。针对工作区地下水硫酸盐化现象开展研究,并对城乡结合部开展综合整治,加强对农业区地下水环境的综合保护,以遏制区内地下水污染趋势,预防地下水污染事件的发生。      

Regional groundwater flow model for Abu Dhabi Emirate: scenario-based investigation

Despite the continuous increase in water supply from desalination plants in the Emirate of Abu Dhabi, groundwater remains the major source of fresh water satisfying domestic and agricultural demands. Groundwater has always been considered as a strategic water source towards groundwater security in the Emirate. Understanding the groundwater flow system, including identification of recharge and discharge areas, is a crucial step towards proper management of this precious source. One main tool to achieve such goal is a groundwater model development. As such, the main aim of this paper is to develop a regional groundwater flow model for the surficial aquifer in Abu Dhabi Emirate using MODFLOW. Up to our knowledge, this is the first regional numerical groundwater flow model for Abu Dhabi Emirate. After steady state and transient model calibration, several future scenarios of recharge and pumping are simulated. Results indicate that groundwater pumping remains several times higher than aquifer recharge from rainfall, which provides between 2 and 5% of total aquifer recharge. The largest contribution of recharge is due to subsurface inflow from the eastern Oman Mountains. While rainfall induced groundwater level fluctuation is absent in the western coastal region, it reaches a maximum of 0.5 m in the eastern part of the Emirate. In contrast, over the past decades, groundwater levels have declined annually by 0.5 m on average with local extremes spanning from 93 m of decline to 60 m of increase. Results also indicate that a further decrease in groundwater levels is expected in most of Emirate. At other few locations, upwelling of groundwater is expected due to a combination of reduced pumping and increased infiltration of water from nonconventional sources. Beyond results presented here, this regional groundwater model is expected to provide an effective tool to water resources managers in Abu Dhabi. It will help to accurately estimate sustainable extraction rates, assess groundwater availability, and identify pathways and velocity of groundwater flow as crucial information for identifying the best locations for artificial recharge.