Post-monsoon Groundwater Levels Research Articles

Exploring available water resources in Bahraich district of Uttar Pradesh: A comprehensive study

Present study was carried out during 2018–22 at Bahraich, Uttar Pradesh focusing on groundwater, runoff, and canal water suggesting that a sizable database is essential for effectively managing water resources. Groundwater quantity was estimated using water level fluctuation (WLF), runoff using GIS coupled with curve number and canal water volume using equivalent length factor methods. This study revealed that the contribution of groundwater was more than 52.5%, whereas runoff (45.61%) and canal water (1.89%). Higher amounts of total available water observed in Mihipurwa (305.3 million cubic meter, MCM), Mahsi (211.6 MCM), Chittaura (189.3 MCM) and Nawabganj (184.4 MCM) blocks due to denser vegetation cover and moderate to low curve number values, while Risia (96.5 MCM) had the lowest amounts of available water in juxtaposition with the other blocks due to high industrial draft, higher drop down in the depth of post-monsoon groundwater level and minimal canal water irrigation. The sandy soil predominant in Jarwal had the lowest annual runoff (117.54 mm) while Nawabganj had the highest (359.84 mm) followed by Balha and Huzoorpur due to having a higher elevation over the other blocks. The runoff ratio was found to be larger in Nawabganj (27.74%), followed by Balha (23.06%) and lowest in Mihipurwa (14.89%) followed by Chittaurah (14.91%). Kaisarganj (11.6 MCM) had the highest amount of canal water resources accessible, followed by Mahsi (6.8 MCM) and Huzoorpur (6.1 MCM), while Balha and Nawabganj had the lowest amounts of canal water resources at 0.1 MCM.

Monitoring the Impacts of Artificial Recharge Structures on Water Table at Ambedkar Nagar, Uttar Pradesh, India

To study the groundwater recharge through rainfall and artificial recharge structures in selected dry well in different locations of UP was experimented. The data was recorded (1998-2017) to execute the artificial recharge structure at the appropriate locations with best geological condition to enhance the recharge rate at least cost for control of declining groundwater level. Study reveals that the stochastic auto regressive lime series model is an effective tool for management of ground water resource at pre and post monsoon. The variation of pre and post monsoon ground water level is maximum as the physical soil characteristics including hydraulic conductivity may enhance the recharge rate at least cost.

Investigating the changing pattern of groundwater levels and rainfall in the peninsular region of Bhagalpur and Khagaria, Bihar

Abstract Groundwater is the primary source of water for domestic and irrigation purposes in the peninsular region of the Bhagalpur and Khagaria districts of Bihar. Though this region is bounded by perennial rivers on three sides, the groundwater level is decreasing gradually because of over exploitation and misuse. In this study, spatial and temporal analyses of rainfall and groundwater levels for pre- and post-monsoon seasons from 1996 to 2020 have been carried out using GIS tools, graphical plots, and statistical methods of pattern recognition. The spatial analysis of rainfall shows less rainfall in the western region of the study area, whereas it shows heavy rainfall in the region near the Vikramshila Bridge. The temporal analysis of rainfall shows decreasing trend in the whole study area and the rate of decrease was 25.05 mm/year during 1996–2020. The results of the pre-monsoon groundwater levels analysis show decreasing trend in the majority of wells, and the rate of decrease varies from 0.005 to 0.102 m/year. By contrast, the post-monsoon groundwater levels showed an increasing trend varying from 0.005 to 0.083 m/year at wells located near the River Ganga, except at Maheshkhunt. Thus, there is a need for proper groundwater management for a sustainable future.

Trend Analysis of Groundwater Levels in Kalpathypuzha Sub-Basin of Bharathapuzha, Kerala in India

Groundwater is one of the most precious and significant sources of water in the world. The understanding of groundwater level variability and trend is crucial for water resources planning in a region. The present study was conducted in the Kalpathypuzha sub-basin of Bharathapuzha. The variability of ground water levels was analyzed using various descriptive statistics such as mean, standard deviation, coefficient of variation, skewness and kurtosis. The groundwater level trend was estimated using the Mann-Kendall test and Sen’s slope estimator. Twelve observation wells evenly distributed in the blocks of Kuzhalmannam, Palakkad, Malampuzha and Chittur blocks of Palakkad districts in Kerala were selected for the study. The results of variability analysis showed that, the highest mean monthly groundwater level of 139.1 m was found for the well 139 of Chittur block in September and the lowest mean monthly groundwater level of 61.5 m was found for the well 129 of Palakkad block in September. The highest mean annual groundwater level was 138.9 m in the year 2007 for the well 139 of Chittur block and the lowest was 62.1 m in the year 2016 for the well 129 of Palakkad block. The results of trend analysis showed a decreasing pre-monsoon groundwater level trend in three wells viz. well 129 of Palakkad block and wells 133 and 142 of Malampuzha block while decreasing post-monsoon groundwater level trend was observed in well 139 of Chittur block. There was no significant trend in the rest of the wells for both the pre-monsoon and post-monsoon periods.

Groundwater Potential Zone Delineation Using Multi-criteria Decision-making Approach: A Case Study

Over-exploitation of groundwater from coastal aquifers causes seawater intrusion and depletion of freshwater resources. As 40 percent of the world’s population live within 100 km of the coast. This will increase the demand for potable water in coastal aquifers. Hence, it is essential to evaluate the sources of fresh-groundwater potential and productivity in coastal aquifers. Nowadays, integrated studies based on geographic-information systems play a major role in groundwater-exploration studies. Thus, the current study was carried out with the objective to delineate groundwater potential in the Nambiyar river basin in Tamil Nadu's southeast coastal area, where groundwater is in a critical condition. In order to improve groundwater recharge, it is very important to identify possible recharge areas. A novel work of the integration of remote sensing, geographic information system (GIS) and multi-criteria decision-making approaches of analytical hierarchical-process methodologies (AHP) was used in the present study. A total of 11 thematic layers, such as slope, curvature, soil, roughness, topographic-wetness index, drainage density, land use/land cover, geology, geomorphology, lineament density and rainfall, were generated for delineating groundwater potential zones. All the thematic maps are weighted using AHP based on the attributes of the classes and the potential capacity of their water supply. The demarked region of groundwater potential was validated by comparing pre-monsoon and post-monsoon groundwater levels. The groundwater potential zone map was classified into five categories: very high, high, moderate, low and very low. Areas with very high and very low potentials are delineated only in very limited areas. 64% of the regions are covered under the moderate-potential zones. The low-and high-groundwater potential zones are delineated at 22% and 14%, respectively. KEYWORDS: GIS, Recharge areas, Groundwater potential, Nambiyar river basin, AHP

Exploration of groundwater potential zones mapping for hard rock region in the Jakham river basin using geospatial techniques and aquifer parameters

Geospatial techniques are useful to understand the groundwater resources assessment, development, and management. Groundwater mapping is essential to counter the excessive withdrawal of groundwater and fulfil the need of drinking, irrigation water in hard rock areas. Currently, the main problem is facing the groundwater level is decreasing due to less rainfall, climate changes and increasing demand, which is under in the hot zones. This results can be more useful for future challenges, sustainable development and demand to Jakham river basin. The main objective of this paper to demarcated the groundwater potential zones (GWPZ) using geospatial techniques for the hard rock region with the reference of aquifer parameters. In this paper, we have used to total eight thematic layers such as geomorphology, land use, soil, topographic elevation, slope, post-monsoon groundwater level (GWL), net recharge, and transmissivity, which are prepared from satellite data and field verification. All thematic layers were integrated for assigning the weights to demarcation of the groundwater potential zones in the RS and GIS environment. The selected thematic layers and features were assigned weightage and normalized by the analytic hierarchy process (AHP) technique. Finally, the thematic layers were systematically integrated using weighted overlay analysis within a GIS environment. We have classified into five GWPZ classes i.e. very high, high, moderate, low, and very low for basin area using GIS, and AHP methods. The study area result indicated that high and moderate zone, which is confined in the central part of the basin, covers 2.43 % and 43.88 % area, respectively. The low (49.21 %) and very low (4.25%) GW potential zone is under the confined aquifer in the high slope and rock outcrops formations near the basin boundary. The final GWPZ map was validated with groundwater level fluctuation data, which illustrates the accuracy of the adopted approach. This unique approach and conclusions of this work may also help to develop the framework and policies for swiftly analyzing groundwater recharge planning, development and locating the artificial recharge structures in the other semi-arid, arid and hard rock regions.

A century of groundwater accumulation in Pakistan and northwest India

The groundwater systems of northwest India and central Pakistan are among the most heavily exploited in the world. However, recent, and well-documented, groundwater depletion has not been historically contextualized. Here, using a long-term observation-well dataset, we present a regional analysis of post-monsoon groundwater levels from 1900 to 2010. We show that human activity in the early twentieth century increased groundwater availability before large-scale exploitation began in the late twentieth century. Net groundwater accumulation in the twentieth century, calculated in areas with sufficient data, was at least 420 km3 at ~3.6 cm yr–1. The development of the region’s vast irrigation canal network, which increased groundwater recharge, played a defining role in twentieth-century groundwater accumulation. Between 1970 and 2000, groundwater levels stabilized because of the contrasting effects of above-average rainfall and the onset of tubewell development for irrigation. Due to a combination of low rainfall and increased tubewell development, approximately 70 km3 of groundwater was lost at ~2.8 cm yr–1 in the first decade of the twenty-first century. Our results demonstrate how human and climatic drivers have combined to drive historical groundwater trends.

Decadal Groundwater Level Changes in Pratapgarh District of Southern Rajasthan, India

The higher dependency on the groundwater has increased extremely over time due to over-utilization of the aquifers. Thus, it is urgent to assess the degree of exploitation and analyze the groundwater level trend in the area of interest. This study has been taken to examine the pre and post -monsoon groundwater level fluctuations using statistical methods for 76 observation wells in Pratapgarh district of Rajasthan for the last 11 years (2009-2019). Results revealed that the groundwater level has fallen general to significantly in maximum number of blocks during 2009-2019. It was found that the resulting groundwater levels are linearly affected by the amount of rainfall occurred. The groundwater level fluctuations data considerably interprets the groundwater recharge. The average annual decline in groundwater level was detected with strong decline (0.204 m/yr) during post-monsoon season at Chhoti Sadriblock. The average rate of rise and decline during pre and post monsoon groundwater level for the Pratapgarh district was 0.110 m/yr and 0.081m/yr, respectively. In spite of being a predominantly hard rock area, the district shows limited variation in depth to groundwater level. The alterations in water level in different seasons may be attributed to the recharge by rainfall in post-monsoon season.

Investigating Groundwater Condition and Seawater Intrusion Status in Coastal Aquifer Systems of Eastern India

Providing sustainable water supply for domestic needs and irrigated agriculture is one of the most significant challenges for the current century. This challenge is more daunting in coastal regions. Groundwater plays a pivotal role in addressing this challenge and hence, it is under growing stress in several parts of the world. To address this challenge, a proper understanding of groundwater characteristics in an area is essential. In this study, spatio-temporal analyses of pre-monsoon and post-monsoon groundwater levels of two coastal aquifer systems (upper leaky confined and underlying confined) were carried out in Purba Medinipur District, West Bengal, India. Trend analysis of seasonal groundwater levels of the two aquifers systems was also performed using Mann-Kendall test, Linear Regression test, and Innovative Trend test. Finally, the status of seawater intrusion in the two aquifers was evaluated using available groundwater-quality data of Chloride (Cl−) and Total Dissolved Solids (TDS). Considerable spatial and temporal variability was found in the seasonal groundwater levels of the two aquifers. Further, decreasing trends were spotted in the pre-monsoon and post-monsoon groundwater-level time series of the leaky confined and confined aquifers, except pre-monsoon groundwater levels in Contai-I and Deshpran blocks, and the post-monsoon groundwater level in Ramnagar-I block for the leaky confined aquifer. The leaky confined aquifer in Contai-I, Contai-III, and Deshpran blocks and the confined aquifer in Nandigram-I and Nandigram-II blocks are vulnerable to seawater intrusion. There is an urgent need for the real-time monitoring of groundwater levels and groundwater quality in both the aquifer systems, which can ensure efficient management of coastal groundwater reserves.

Prediction and forecast of pre-monsoon and post-monsoon groundwater level: using deep learning and statistical modelling

Prediction and forecast of pre-monsoon and post-monsoon groundwater level: using deep learning and statistical modelling

Long-term sustainability of groundwater resources in the central Ganga Alluvial Plain, India: Study from Gomti River Basin

Groundwater is the major primary source of drinking and irrigation water for nearly 500 million inhabitants in both rural and urban areas of the Ganga Alluvial Plain (GAP) in India. Indiscriminate pumping of groundwater primarily from the shallow parts of the alluvial aquifer system is leading to rapid decline in water tables. It is expected that in coming years, the stress on groundwater will only increase due to steadily rising urbanization and additional demands for water and land, as well as by impending weather anomalies and shifts in availability of water during seasons when demands for irrigation and ecological needs are high. In the present study, Inverse Distance Weighted (IDW) interpolation method is used using pre- and post-monsoon groundwater levels from 764 observatory wells and peizometers to assess the trends of declining groundwater in the Gomti River Basin (GRB) during 2005 to 2015. Groundwater potential zone maps were composed using water depths data and Cartosat-1 satellite images delineating the area under rising and falling groundwater tables. The loss of shallow groundwater was clearly visible during the 2005–2015 periods. The decline is attributed to intensive irrigation from groundwater as well as peri-urban growth around the state capital. This study can apprise the planners and local administrators of the effects of irrigation and urbanization on the groundwater regime in the fast growing regions of the basin.

Assessment of groundwater depletion–induced land subsidence and characterisation of damaging cracks on houses: a case study in Mohali-Chandigarh area, India

The present study identified groundwater depletion–induced land subsidence by spaceborne differential interferometric SAR (DInSAR) technique and assessed the damaging impacts of land subsidence by characterising the cracks on houses in Mohali-Chandigarh area of India. First, we identified groundwater depletion hot spots using pre-monsoon and post-monsoon groundwater-level (GWL) data of Central Ground Water Board (CGWB), India, for the period of 2005–2018. Both conventional and advanced DInSAR techniques were used to identify temporally consistent subsiding areas and measure precise rates of subsidence in and around groundwater depletion hot spots. We studied the damaging impacts of land surface deformation by characterising the damaging cracks on houses in affected areas. Groundwater depletion and resulting aquifer-system compaction increase effective stress on confining clay layer which leads to stress build-up at the soil-structure interface and causes damaging cracks on houses. A variety of damaging cracks on houses were observed at the affected areas such as Sohana, Landran, Kharar and Kurali localities. We attempted to characterise the damaging cracks on the basis of shape, size, orientation, surface morphology and texture of the cracks; sense of ground movement; and nature of stress build-up at the interface. We identified tensional cracks, compressional cracks and shear cracks with diverse orientations and separation widths. Finally, a comparative assessment of groundwater depletion, land subsidence and damaging impacts on houses has been made. Using DInSAR technique, we identified land subsidence in and around the groundwater depletion areas in Sohana and Landran (both in Mohali City area), Kharar and Kurali (in Mohali district outside Mohali City area) and Sectors 27–28 in Chandigarh with radar line-of-sight subsidence rates of ~6–7.5 cm/year, ~5.5–6.5 cm/year, and ~ 4 cm/year respectively. We observed that the houses in and around Landran appears to be worst affected followed by Kharar, Sohana and Kurali. From this study, it appears that the type of construction of the houses, e.g. prevalence of masonry and reinforced masonry structures, is primarily responsible for the worst damaging impacts of the houses in Landran and Kurali areas besides the magnitude of land subsidence.

Groundwater Modeling of Huzur Tehsil, M.P Using GIS Techniques

Huzur Tehsil, district Bhopal city in the Madhya Pradesh state of India has faced the problem of groundwater availability in recent times believed largely due to rapid urbanization coupled with the presence of increasing Population and the urban sprawl increase the number of bores well in earth, which is the reason to the declination of groundwater level. That means water is very important for the sustained use of natural resources and is vital for the existence of mankind. Groundwater used for a variety of purposes, including irrigation, drinking, and manufacturing. For assessing the groundwater Level suitability zones through GIS techniques, this study was undertaken in the Huzur Tehsil, Bhopal district, Madhya Pradesh. Artificial recharge is expected to become increasingly necessary in the future as the growing population requires more water and thus, more storage is required to conserve water for use in times of shortage. Geospatial techniques employing Geographical information systems (GIS) are increasingly being used in the field of hydrology and water resources development. This is the greatest advantage of using GIS techniques for Groundwater level (bore well) investigations and monitoring is its ability to generate information in water level behavioral conditions, which is provided very critical for successful analysis, prediction, and validation. In the present study, the Kriging technique was used to interpolate the groundwater levels. Interpolation of pre and postmonsoon groundwater levels was carried out for the year 1996-2017. Finally, we generated the fluctuation maps were showing the fluctuation in the pre-post monsoon period between the years, 1996-2000, 2001-2005, -2010 and 2011-2017 and Long term trend fluctuation maps were generated showing, and finally, Feature Projected Groundwater Level map are generated 2018-2051 period, and showing the Groundwater Level trend (1996-2051) since. For visualization groundwater level depth (mbgl) and Fluctuation, in the pre and post-monsoon period, showing the 3D Surface modeling using Matlab tools. DOI: https://doi.org/10.23953/cloud.ijarsg.455

Identification of risk zone area of declining piezometric level in the urbanized regions around the City of Kolkata based on ground investigation and GIS techniques

The falling piezometric level of groundwater is one of the major concerns, because of its immense importance especially in areas where treated surface water is not easily accessible. An attempt is made to identify the areas of maximum depletion of groundwater in KMC area by studying the post monsoon groundwater level data for the years 1991–2010. The Arc GIS software is used for the representation of the secondary data and also for the easy comparison of data. The study is done to find the groundwater trough in the region by predicting the groundwater level for post monsoon 2018 and validating the result with the data collected from the field. The result thus obtained is analysed with the help of the said software using the IDW (Inverse Distance weightage) technique. Thus, it is seen that GIS forms an excellent platform for the analysis of groundwater data and is very helpful in the present study. A comparative analysis has been made and it is seen that at maximum places in KMC region the water level is receding-places like Narendrapur, Chitpur, Sinthi, Ballygunge, Park Street, Jadavpur all show a receding trend, few places being exception like Mukundapur, Kalikapur where there has been a slight rise in the groundwater level, over the years. With the advancement in the surface water supply by the Kolkata Municipal Corporation and with the decrease in population density, there is no respite in the groundwater level recession in the city. Blessed with river Hooghly alongside, the potable water issue is solved to a greater extent but still the southern Kolkata shows dependence on groundwater. Due to the falling groundwater level the chances of land subsidence is seem to be high in the city.

Trend analysis of river flow and groundwater level for Shipra river basin in India

The declining baseflow and drying up of river during the lean period are important issues in major rivers systems in India. In recent times, more focus has been given to formulate an action plan for river rejuvenation. The present study aims at the assessment of declining flow regime in Shipra river in the Madhya Pradesh state of India. Long-term daily runoff data recorded at the Ujjain gauge discharge site on Shipra river was analyzed to identify trends in dependable flows using a non-parametric Mann–Kendall test. The declining trend for dependable river flow at various probability levels was observed at Ujjain during the beginning of monsoon (month of July) and at the end of monsoon (months of September and October). However, a rising trend was observed during the mid-monsoon season (month of August). The trend analysis of pre-monsoon and post-monsoon groundwater level data indicated falling groundwater level trend in the entire Shipra basin. Significant declining trends in groundwater levels were observed in the middle reach area of the basin where important cities like Indore and Ujjain are located. Wigley and Jones’s index was used to judge the rising or declining flow regime of Shipra river. Average annual rainfall, as well as river runoff, has decreased substantially during the last two decades. The trend analysis of flow and groundwater level data of the Shipra river basin and information derived using Wigley and Jones index will be useful to formulate strategies for the river rejuvenation planning.

Exploring temporal dynamics of spatially-distributed groundwater levels by integrating time series modeling with geographic information system

This study developed a novel framework for integrating time series modeling with geographic information system (GIS). For the first time, procedures of four statistical tests, i.e., t-test of stationarity, cumulative deviation test of homogeneity, autocorrelation technique of persistence, and variance-corrected Mann–Kendall test of trend, are implemented in GIS platform to enable use of raster dataset. Application of developed framework is demonstrated by exploring time series characteristics of pre- and post-monsoon groundwater levels in an Indian arid region. Raster dataset of 22-year (1996–2017) groundwater levels are generated using four best-fit geostatistical models, according to mean absolute error, root mean square error, correlation coefficient and modified index of agreement. Increasing groundwater level trends in central and southern parts are attributed to abrupt change-points in annual rainfall that enhanced groundwater recharge. The developed framework can be adopted in other parts of the world to explore groundwater-level dynamics in spatially-distributed manner.

Groundwater recharge estimation studies in a khondalitic terrain of India

Agriculture is the main occupation in the Kandivalasa river sub-basin (KRSB) covered with khondalitic terrain of Eastern Ghats of India. The farmers are mainly depending on groundwater for irrigation in non-monsoon period in the study area; as such it is important to know how much rainfall recharge is occurring to the groundwater table. The groundwater recharge is assessed in the KRSB by collecting the pre- and post-monsoon groundwater levels at 42 observation wells and rainfall data covering the entire basin during the years 2013–2016. The groundwater recharge has been calculated using both water table fluctuation method and rainfall infiltration method. The study revealed in the basin that the per cent of rainfall converting to the groundwater recharge is 11.12, 13.18, 9.51 and 12.80% for the years 2013, 2014, 2015 and 2016, respectively. The study has also revealed that the heavy rainfall events with prolonged time lead to the rise in the groundwater levels, thereby increasing the groundwater recharge. It is also observed that the deeper the pre-monsoon groundwater level, the more the recharge in the basin.

Spatio-temporal analysis of groundwater levels and projection of future trend of Agra city, Uttar Pradesh, India

Access to water resources is one of the major challenges being faced worldwide. Water scarcity, particularly groundwater resource, is the major ubiquitous concern for the country. Almost half of the country is reeling under severe ground water crisis due to anthropogenic and natural reasons (basalt rock surface). Agra region situated in the western part of Uttar Pradesh state of India has a semi-arid climate. The study area, which has a history of water scarcity since medieval ages, has seen a spurt of acute water shortage in recent times owing to the expansion of a very dense built-up area and excessive haulage accompanied by decline in rainfall. A study was under taken for identifying the trends in pre- and post-monsoon groundwater levels for Agra city, Uttar Pradesh. Pre-monsoon and post-monsoon groundwater depth data of 16 observation wells for the 2007–2016 period were collected and analyzed using ARC GIS 10.2 software. The rainfall trend during the study period was also studied to understand its role in groundwater fluctuation level. Statistical tests like Mann-Kendall, Sen’s slope estimator, and linear regression model were applied to understand the trend and rate of change in groundwater level. The land use/land cover map of the study area was integrated with groundwater map to have a primary understanding of the spatial trend of groundwater scenario of the study area. The result obtained is quite alarming for the city’s groundwater scenario. Results showed that the groundwater levels had significantly declined during 2007–2016. Average rates of water level decline were 0.228 and 0.267 m/year during pre- and post-monsoon seasons, respectively. There was a rapid decline in water level between 2008 and 2009 and between 2013 and 2014. The average rate of decline of pre- and post-monsoon groundwater level in the city during this period is 0.32 and 0.30 m/year, respectively. Significant decrease in groundwater level is found in 84.21% of wells for pre- and post-monsoon as obtained through Mann-Kendall analysis at 95% confidence level. During pre-monsoon season, the rate of decline according to Sen’s slope estimator varied between 0.74 and 2.05 m/year. Almost similar picture of decline is portrayed through linear regression slope wherein the computed rate of decline varied between 0.75 and 2.05 m/year. During post-monsoon, the rate of decline according to Sen’s slope varied between 0.13 and 1.94 m/year. Similar trend statistic is obtained through linear regression method where the declining rate is between 0.14 and 1.91 m/year. Comparison of the three statistical tests indicates similar nature of declining trend. The result of this research raises concern about the future of groundwater resources in Agra city. The findings of this study will assist planners and decision-makers in developing better land use and water resource management.

Hydro-meteorological and agricultural trends in water-scarce Karha Basin, western India: current and future scenario

The scientific understanding of hydro-meteorological and agricultural changes in the water-scarce region is crucial to formulate a plan for sustainable management of water resources and cropping pattern under the scenario of climate change. The present investigation, therefore, has attempted to detect the trends in the monsoon rainfall, runoff, dam storage, post-monsoon groundwater (PMGW) levels, and agricultural data in the Karha Basin, located in the rain shadow zone of the Western Ghat. Additionally, trends in projected monsoon rainfall and average annual temperature were also analyzed. The study indicates no significant increase in monsoon rainfall over the basin during past (1981–2013) and future (2015–2050). The noteworthy decline in monsoon runoff has mainly resulted due to the effective implementation of surface water harvesting in the basin, which has a significant positive change in PMGW table in the basin. The study also provides evidence of the shift in agricultural pattern, where the rainfed crops are getting replaced by the high water-requiring/cash crops. It may increase the future agricultural water demand and pressurize the limited water resources in the basin. On the other hand, significant increase in near-term future (up to 2050) temperature can augment the water demand along with the adverse impacts on the agricultural productivity. The Karha Basin is already suffering from water deficiency. The man-induced increase in agricultural water demand and the adverse climatic changes in the Karha Basin are very likely to aggravate the future drought conditions and further add to an already difficult water management challenge in the basin.

Evaluating the impact of artificial groundwater recharge structures using geo-spatial techniques in the hard-rock terrain of Rajasthan, India

Groundwater levels in hard-rock areas in India have shown very large declines in the recent past. The situation is becoming more critical due to a paucity of rainfall, limited surface water resources and an increasing pattern of groundwater extraction in these areas. Consequently, the Ground Water Department with the aid of World Bank has implemented the water structuring programme to mitigate groundwater scarcity and to develop a viable solution for sustainable development in the region. The present study has been undertaken to assess the impact of artificial groundwater recharge structures in the hard-rock area of Rajasthan, India. In this study groundwater level data (pre-monsoon and post-monsoon) of 85 dug-wells are used, spread over an area of 413.59 km2. The weathered and fractured gneissic basement rocks act as major aquifer in the area. Spatial maps for pre- and post-monsoon groundwater levels were prepared using the kriging interpolation technique with best fitted semi-variogram models (Spherical, Exponential and Gaussian). The groundwater recharge is calculated spatially using the water level fluctuation method. The entire study period (2004–2011) is divided into pre- (2004–2008) and post-intervention (2009–2011) periods. Based on the identical nature of total monsoon rainfall, two combinations of average (2007 and 2009) and more than average (2006 and 2010) rainfall years are selected from the pre- and post-intervention periods for further comparisons. All of the water harvesting structures are grouped into the following categories: as anicuts (masonry overflow structure); percolation tanks; subsurface barriers; and renovation of earthen ponds/nadis. A buffer of 100 m around the intervention site is taken for assessing the influence of these structures on groundwater recharge. The relationship between the monsoon rainfall and groundwater recharge is fitted by power and exponential functions for the periods of 2004–2008 and 2008–2011 with R 2 values of 0.95 and 0.98, respectively. The average groundwater recharge is found to be 18% of total monsoon rainfall prior to intervention and it became 28% during the post-intervention period. About 70.9% (293.43 km2) of the area during average rainfall and more than 95% (396.26 km2) of the area during above-average rainfalls show an increase in groundwater recharge after construction of water harvesting structures. The groundwater recharge pattern indicates a positive impact within the vicinity of intervention sites during both average and above-average rainfall. The anicuts are found to be the most effective recharge structures during periods of above-average rainfall, while subsurface barriers are responded well during average rainfall periods. In the hard-rock terrain, water harvesting structures produce significant increases in groundwater recharge. The geo-spatial techniques that are used are effective for evaluating the response of different artificial groundwater recharge techniques.