Introduction

Chemical quality of surface and groundwater of an area is influenced by the climate, hydrological conditions, soil characteristics and geological formation. Irrespective of their source, all natural waters contain some chemical constituents and their quality changes progressively as they traverse over the land surface or infiltrate downward due to various hydro-geochemical processes. Anthropogenic factors also contribute substantially towards quality change of both surface water and ground water. In the present study an attempt has been made to understand the aquifer vulnerability to pollution, at the regional scale (Goa State), which takes into account the intrinsic hydraulic and hydrogeological parameters and environmental impacts. It is noticed that a variety of activities, such as agricultural, industrial and urban land uses, are carried out in the area, thus exposing the aquifers to a wide range of contaminants. Groundwater quality data of Goa state for the pre-monsoon seasons of 2014 and 2018 were obtained from CGWB (Bengaluru) and analysed statistically. A regional scale approach was developed which is known as ABHESHT (Aquifer type, Boundary conditions, Hydraulic Head representing static water level, Environmental impact, Solute concentration, Head variation (Water Table Fluctuation) during pre-monsoon and post-monsoon seasons and Transmissivity). The method has been applied to Goa State, west coast of India and compared with the observed groundwater quality parameters. It is found that the model has successfully delineated the wells which are prone to pollution. Using GALDIT model, seawater intrusion impact was also assessed. The study revealed that the groundwater of Goa State did not show any significant pollution indicator, however, seasonal variations in water quality parameters were observed. It is also found that the North Goa coast as well as the other tourist spots spread over the entire state show signs of pollution at various locations (Anjuna. Baga, Mapusa. Concona etc). This calls for immediate attention from the concerned authorities.

Rajasthan is the largest state of India covering an area of 3,42,239 sq.km and represents 10.5% of the country?s geographical area. On the other hand it has only 1.15% of total surface water and 2.6% of dynamic groundwater resources of the country?s resources due to arid climatic conditions. Surface water availability is restricted to command areas of canal system; hence groundwater is the only dependable source in major part of the state. Groundwater quality deterioration with depth coupled with low and erratic rainfall has generated constraints as regards availability and development potential of groundwater resources. Over exploitation of groundwater has caused mining of groundwater, which has set in declining trend in water level and threatening depletion of limited available fresh groundwater resources at an alarming rate. Management of groundwater resources in this context is an extremely complex proposition. The highly uneven distribution of groundwater and its utilization make it impossible to have single management strategy for Rajasthan as a whole. Any strategy for scientific management of groundwater resources should involve a combination of supply side and demand side measures depending on the regional setting and local geology and also on use of saline water. There are saline water tracts in various parts of the state. Recently conservation of water through crop diversification and use of saline water in several parts of the state has gained momentum.

As per the assessment of the dynamic ground water resource in Gujarat the utilsable ground water resources have been assessed as 24905 MCM, after providing for natural discharge (March 2021). The annual ground water draft is 13296 MCM. The Stage of ground water development works out to be about 53%. However, this is not uniform across the state. The stage of development is exceedingly high in North Gujarat and Kachchh regions. Highly intensive development of ground water in these areas has resulted in over - exploitation leading to the decline of ground water levels, deterioration in the ground water quality and sea water intrusion in the coastal areas. The paper presents existing scenario of various supply and demand side interventions implemented in the state with their impact. Recommendations for various interventions necessary for sustainable ground water management have been made with particular emphasis on use of scientific inputs from the supply as well as demand side interventions to the community participation in planning, implementing and monitoring.

In general, Chhattisgarh state is underlain by hard rocks with limited groundwater potentials. But decline of rainfall in most parts of the state is limiting surface water resources too. Agriculture is mostly rainfed, paddy being the main crop in the state. Groundwater is the main source of irrigation and a major source of drinking water. Cavernous limestones/dolomites form the most potential aquifers yielding up to 50 lps as in Bastar, Baloda Bazar and Bilaspur districts. Proposal for construction of energized irrigation dug/bore wells under PMKSY-HKKP-GW scheme in 109 blocks (stage of extraction within 60%) of 7 aspirational districts will enhance ground water irrigation of 7467 ha land. The stage of extraction has already escalated from 5.11% (1990) to 44.43% (2017) which will be escalated further with ongoing and future development programs. The State should undertake conservation of groundwater through regulation, protection and augmentation of the water resources by implementing rainwater harvesting and artificial recharge, along with adoption of rainfed agriculture, drip or sprinkler irrigation, pricing policy for commercial ground water extraction, exploration and planned development of yet unknown aquifers through exploratory drilling aided by remote sensing, geophysics . Based on declining groundwater level trends areas totalling 16,410 sq. km have been demarcated for rainwater harvesting and artificial recharge creating sub-surface ground water storage potential of 1030.11 MCM and an additional irrigation potential of 148430 ha. Further, groundwater pollution from geogenic and anthropogenic sources like high fluoride, arsenic, uranium, sulphate, nitrate as in Rajnandgaon, Durg, Bilaspur, Raipur and Kwardha districts is also a potential threat to the utilisable resources.This paper attempts at a holistic overview of sustainable development and management of ground water resources of the state considering the huge hydrogeological, geophysical and chemical database in the state.

Surface water resources in Rajasthan are scarce and scanty owing to hot arid climatic conditions. Major parts of western Rajasthan are devoid of any major drainage system and are reeled under spells of chronic droughts. Average annual rainfall in the state is of the tune of 540mm, decreases westward and is even less than 150mm in the western most parts of Jaisalmer district. Annual Potential evapo-transpiration is also as high as 2060mm in parts of Jaisalmer district. There are 15 river basins in the state. There are also numerous natural as well as artificial freshwater lakes including Pushkar, Rajsamand, Nakki, Ana Sagar, Kayalana, Ramgarh, Foy Sagar etc. mainly in the southern and eastern parts of the state. Salt lakes include Sambhar, Kuchaman, Pachpadra, Didwana, Phalodi, Lunkaransar etc. Indira Gandhi Nahar (IGNP), Bhakara and Gang canals have been constructed to bring Himalayan water to the desert areas of western Rajasthan in addition to other major commands of Chambal, Mahi and Narmada canals etc. In Rajasthan, irrigation projects completed include 22 Major projects, 77 Medium projects, 660 Minor projects and 3139 Tanks have been transferred to Panchyat Raj Department. Usable water is of the magnitude of 16.05 BCM and the Gross Storage Capacity created is of the order of 14.547 BCM. The Live Storage Capacity created is about 11.99 BCM. Out of the total allocated share of 17.88 BCM under interstate water agreement, average annual water availability remains 12.66 BCM due to various climatic, political, institutional or hydrological reasons. In addition to various Central Government Schemes, Watershed schemes and Mukhyamantri Jal Swavlamban Abhiyan are also implemented in the state.