Agricultural groundwater management in the Upper Bhima Basin, India: current status and future scenarios

The basaltic aquifers of the Upper Bhima River basin in southern India are heavily utilized for small-scale agriculture but face increasing demand-related pressures along with uncertainty associated with climate change impacts. To evaluate likely groundwater resource impacts over the coming decades, a regional groundwater flow model for the basin was developed. Model predictions associated with different climate change and abstraction scenarios indicate that the continuation of current rates of abstraction would lead to significant groundwater overdraft, with groundwater elevations predicted to fall by -6 m over the next three decades. Groundwater elevations can however be stabilized, but would require 20-30% of the mean surface water discharge from the basin to be recharged to groundwater, along with reductions in pumping (5-10%) brought about by improved water efficiency practices and/or shifts towards lower-water use crops. Modest reductions in pumping alone cannot stabilize groundwater levels; targeted conjunctive use and improved water use efficiency are also needed

Integrating cost and benefit considerations with supply- and demand-based strategies for basin-scale groundwater management in South-West India

Efforts to reverse groundwater depletion in hard-rock regions by enhancing aquifer recharge with valuable surface water present complex challenges and trade-offs related to upstream-downstream interactions and equity. Here, groundwater modelling is used in combination with economic valuation techniques to assess the effectiveness of alternative supply and demand measures under different climate change scenarios in an upper sub-basin of the Krishna River basin in India. It is found that aquifer recharge provides benefits for the sub-basin that are not apparent at the basin scale.Water recharged or crops selected in upper catchments should aim to generate economic benefits that outweigh losses faced downstream

Reckoning Groundwater Quality and Hydrogeochemical Processes for Drinking and Irrigation Purposes under the Influence of Anthropogenic Activities, North India

The present study was carried out near an industrial area with a high-density urban population and large-scale agricultural activities. These anthropogenic activities lead to groundwater pollution and depletion of the water table. This study attempted to classify pollution sources and hydrochemical facies that help to ensure the suitability of water for agriculture and drinking. Irrigation suitability indexes, water quality index (WQI), principal component analysis (PCA), and hierarchical cluster analysis (HCA) were applied to twenty-six groundwater samples that were analysed during May 2018 for major cations and anion concentrations. The results revealed that the mechanism of groundwater chemistry has been controlled by the evaporation process with the dominance of hydrochemical facies viz., Ca-Mg-HCO3, Na-K-Cl-SO4, Ca-Mg-Cl, and Na-K-HCO3. The mean dominant concentration for cations is in the order of Ca2+ > Na+ > Mg2+ > K+ while anions are HCO3− > SO4− > Cl− > NO3− > CO32− > F−. Irrigation suitability indexes indicated that groundwater in the study area is high in saline and low to medium alkali hazards due to industrial activities. The PCA and HCA also recognized that most of the variations are elucidated by anthropogenic processes, predominantly due to excessive population, industrial emissions, and agricultural activities. Further, the WQI of the study area suggested that 15% of the samples were unsuitable, 69% poor, and the remaining 16% only suitable for drinking purposes. The present article helps to understand the suitability and hydrochemical processes of groundwater for irrigation and drinking, which will help policymakers in water supply planning and management

Persistence of heavy metals and human health risk assessment in the South Indian industrial area

The present study provided a comprehensive evaluation of heavy metal contamination from soil to groundwater and the associated risk to human health in an industrial area situated in Telangana state, South India. Soils at three depth levels (0, 20, and 80 cm) and groundwater samples at 32 locations have been collected in the area. The samples have been analyzed for trace metals (Mn, B, Zn, Cr, Pb, Ni, Hg, Cd, and As) to understand the heavy metal contamination. Furthermore, geo-accumulation (Igeo) of heavy metals, contamination factor, pollution index, and human health risks due to prolonged exposure to contaminated water are estimated. The results indicated that soils are moderately contaminated at 18.5, 25.9, 7.4, 14.8, and 7.1% of locations by B, Zn, Cr, Pb, Ni, and Cd, respectively, as per Igeo at 80-cm depth. However, the contamination factor indicated that 14.8% of the locations were contaminated by Mn and Zn and 7.4, 70.3, 66.6, 74, and 3.7% by B, Cr, Pb, Ni, and Cd, respectively. However, groundwater is only contaminated when levels are less than 3 m below ground level. The results also indicated higher carcinogenetic health risks if groundwater is used for a longer time. HIGHLIGHTS Heavy metal pollution load and associated health risks are assessed for the study area.; Soils are moderately contaminated at 18.5, 25.9, 7.4, 14.8, and 7.1% of locations by B, Zn, Cr, Pb, Ni, and Cd, respectively.; Higher carcinogenetic health risks for infants, children, and teens are identified at 28.5, 21.4, and 7.1% of locations.; Groundwater is contaminated when the water table is shallow (<3 m bgl).

Reckoning Groundwater Quality and Hydrogeochemical Processes for Drinking and Irrigation Purposes under the Influence of Anthropogenic Activities, North India

The present study was carried out near an industrial area with a high-density urban population and large-scale agricultural activities. These anthropogenic activities lead to groundwater pollution and depletion of the water table. This study attempted to classify pollution sources and hydrochemical facies that help to ensure the suitability of water for agriculture and drinking. Irrigation suitability indexes, water quality index (WQI), principal component analysis (PCA), and hierarchical cluster analysis (HCA) were applied to twenty-six groundwater samples that were analysed during May 2018 for major cations and anion concentrations. The results revealed that the mechanism of groundwater chemistry has been controlled by the evaporation process with the dominance of hydrochemical facies viz., Ca-Mg-HCO3, Na-K-Cl-SO4, Ca-Mg-Cl, and Na-K-HCO3. The mean dominant concentration for cations is in the order of Ca2+ > Na+ > Mg2+ > K+ while anions are HCO3− > SO4− > Cl− > NO3− > CO32− > F−. Irrigation suitability indexes indicated that groundwater in the study area is high in saline and low to medium alkali hazards due to industrial activities. The PCA and HCA also recognized that most of the variations are elucidated by anthropogenic processes, predominantly due to excessive population, industrial emissions, and agricultural activities. Further, the WQI of the study area suggested that 15% of the samples were unsuitable, 69% poor, and the remaining 16% only suitable for drinking purposes. The present article helps to understand the suitability and hydrochemical processes of groundwater for irrigation and drinking, which will help policymakers in water supply planning and management

Use of geophysical and hydrochemical tools to investigate seawater intrusion in coastal alluvial aquifer, Andhra Pradesh, India

India has a very long coastline and 25 % of the country’s population live in the coastal zone. Urban centers are located along the coast and three out of four metro cities are located on the coast. The high population density along the banks of major rives and coast Increasing population and demand for water putting the coastal aquifers under stress and causing sea water inrush and salinity upcoming in the coastal aquifers. Apart from sea water contamination, urban waste releases and agriculture inputs threatening the coastal groundwater aquifer systems. Generally coastal areas receive more pollutant loads from different sources including geogenic and anthropogenic sources. Central Godavari delta is located adjacent to the Bay of Bengal Coast, Andhra Pradesh, India and is drained by Pikaleru, Kunavaram and Vasalatippa drains. The area is occupied by recent Quaternary alluvium and gone through a series of marine transgression and regression. The entire study area comes under Godavari central canal command area, water is available throughout year except first week of June and last week of April in the canals. Water requirements for irrigation met from surface water in the delta. There is no groundwater pumping for agriculture as wells as for domestic purpose due to brackish nature of the groundwater at shallow depths. The groundwater depths varying from 0.8 to 3.4 m dug wells and in bore wells located near the coast 4.5–13.3 m. The established groundwater flow direction is to be towards Bay of Bengal from Amalapuram. Geophysical and hydrochemical tools were applied to identify the source of the salinity and to assess the saline water intrusion in the Godavari delta. Electrical Resistivity Tomography (ERT) surveys were carried out at several locations in the deltaic region to delineate the aquifer geometry and to identify saline water aquifer zones. The results inferred from ERT indicate 12–15 m thick loamy sands were existed from surface to subsurface and it is followed by 18–25 m thick clay layers. The thickness of clay is being increased toward Sea from inland. The low resistivity values in the delta are attributed to existence of the thick marine clays in the subsurface and relative high resistivities are attributed to existence of fresh water. The resistivity values similar to saline water 0.86) and SO4 -2/Cl- (0.05) indicated marine palaeo salinity, dilution of marine clays and dissolution of evaporites. The high SO4 -2/Cl in the post monsoon is attributed to dilution groundwater salinity due to rainfall infiltration and irrigation return flows in the delta. The low Na+2/Cl- ratios in upstream of the delta are due to sand exposures and isolated fresh water lances in the perched aquifers

Groundwater Evaporation Ponds: A Viable Option for the Management of Shallow Saline Waterlogged Areas

The province of Punjab is the main food basket of India. In recent years, many regions of Punjab are facing acute waterlogging problems and increased secondary salinity, which have negative impacts on food security of the nation. In particular, these problems are more pronounced in the Muktsar district of Punjab. The observed groundwater levels trend between 2005 and 2011 implies that groundwater levels are coming towards the land surface at the rate of 0.5 m/year in Lambi and Malout blocks. In this study, a groundwater flow model was constructed using MODFLOW to understand the groundwater table dynamics and to test the groundwater evaporation ponds to draw down the groundwater levels in the waterlogging areas of Muktsar district. The predicted flow model results indicate that groundwater levels could be depleted at the rate of 0.3 m/year between 2012 and 2018 after the construction of Groundwater Evaporation Ponds (GEP). In addition, the constructed ponds can be used for aquaculture that generates additional income. The proposed GEP method may be a promising tool and suitable for the reduction of waterlogging in any region if there is no proper surface drainage, and also for enhancement of agricultural production that improves the social and economic status of the farming community

Novel conjunctive groundwater-surface water management for controlling floods and droughts [Abstract only]

Well-targeted programs of conjunctive use of groundwater and surface water can help overcome the problem of both floods and droughts, or in other terms meet the water demands for domestic as well as irrigation needs during the dry season. Addressing this, a novel form of conjunctive use management has been developed that involves strategically recharging floodwater in upstream areas to boost small-scale groundwater irrigation and to protect floodaffected areas downstream. For this, choice of site is a crucial component to implement the approach. A method was devised using GIS tools using readily available data from secondary sources to arrive at a suitability index to rank prospects across the entire Ganges basin. This basin was chosen because it has a well-known history of devastating flooding events and water shortage in dry months and is one of the largest and most heavily populated river basins in the world. Numerical modelling is being applied to an area characterized as having high prospects to help to understand the interactions between the groundwater and surface water and the impact of floods on groundwater system. One of the main components to be identified from the model is the peak flows to be captured successfully for recharge. This utilisation of high flows by diverting from the rivers to storage structures introduced within the model will help to identify the potential to manage and reduce the flood impact. This model can help to decide on the size and placement of the structures to store water for maximum recharge and subsequently in watershed management. The relationship between floodwater storage and recharge, and the optimisation of these two processes can also be brought out. Opportunities for conjunctive use of water identified by mapping and the understanding gained from modelling is to be piloted out in one of these sites to establish technical and institutional feasibility with the view to promoting larger-scale implementation

Reviving the Ganges water machine: potential and challenges to meet increasing water demand in the Ganges River Basin

Although the Ganges River Basin (GRB) has abundant water resources, the seasonal monsoon causes a mismatch in water supply and demand, which creates severe water-related challenges for the people living in the basin, the rapidly growing economy and the environment. Addressing these increasing challenges will depend on how people manage the basin’s groundwater resources, on which the reliance will increase further due to limited prospects for additional surface storage development. This report assesses the potential of the Ganges Water Machine (GWM), a concept proposed 40 years ago, to meet the increasing water demand through groundwater, and mitigate the impacts of floods and droughts. The GWM provides additional subsurface storage (SSS) through the accelerated use of groundwater prior to the onset of the monsoon season, and subsequent recharging of this SSS through monsoon surface runoff. It was identified that there is potential to enhance SSS through managed aquifer recharge during the monsoon season, and to use solar energy for groundwater pumping, which is financially more viable than using diesel as practiced in many areas at present. The report further explores the limitations associated with water quality issues for pumping and recharge in the GRB, and discusses other related challenges, including availability of land for recharge structures and people’s willingness to increase the cropping intensity beyond the present level