Groundwater Resources of Rajasthan: Status, Issues and Strategies

Drylands of arid Rajasthan are well known for Drought and hot Desert having diversified hydro-geological conditions. Potential aquifer systems include unconsolidated (Quaternaries deposits), semi-consolidated (Tertiary Sandstone, Lathi Sandstone etc.) and fissured consolidated formations. Groundwater level is generally deep especially in western Rajasthan, where it reaches even 150m below land surface. Quality of groundwater is poor in many parts due to geogenic and anthropogenic reasons. Stage of groundwater development in the State is 139.88% with 185 blocks categorized as over-exploited. Groundwater related issues include deep and declining water levels, low groundwater recharge, over-exploitation, drying up of potential aquifer systems, high salinity, fluoride and nitrate concentration, industrial pollution, water logging and lack of appropriate water management. Management options include supply side and demand side measures i.e. water conservation, regulation, protection and especially structural measures for augmentation of resources by large scale artificial recharge of aquifers, for which financial provisions by the Government/incentives to individuals need to be introduced. Scope for artificial recharge of aquifers exists on account of availability of thick permeable geo-formations, deep & declining water levels, and availability of surplus monsoon water in northwest India, which otherwise goes waste flowing to the neighbouring country. Regulatory measures including notification of 35 block areas, mandatory provision for issuance of NOC for industries/ infrastructure/mining projects for controlled groundwater withdrawal. etc. are being taken up by Govt. organizations. State Water Policy is in place and rooftop rainwater harvesting is to be made mandatory for all buildings. State Ground Water Legislation and State Ground Water Authority need to be constituted and regulatory measures be enforced by Rajasthan Government in line with CGWA. There is need for integrated participatory approach of water management. Rajasthan being the most water deficit State in India, deserve to be given ?Special Status for Water Resources? for financial and other purposes by Government of India.

The Upper Nira River Basin (378.83 km2), in the Upland Deccan Traps is witnessing a transition from being a traditional rain fed, non-command entity to a predominantly surface irrigation command area. Understanding and accurately computing the change in groundwater storage is a vital component in groundwater estimation. The lava flows constitute 3 aquifers in the basin, UNR-1 , UNR-2 and UNR-3. The efficacy of the methodologies used for estimating the groundwater potential of the Upper Nira River Basin is evaluated. Groundwater assessment based on the GEC 2015 methodology has been undertaken to estimate a net available recharge of 4419 Ham in the aquifers and gross groundwater draft of 461.49 ham. The basin has been categorised as Safe due to low stage of exploitation (~11%). The people residing in the basin however face severe scarcity of groundwater during the summer season annually in spite of receiving copious rainfall (about 1500 mm) during the monsoon. The likely reasons for such a paradox are high surface runoff, low permeability, low storativity of aquifers, high base flow plus draft, etc. According to the new and simple aquifer-based methodology proposed in this paper the quantity of recharge (Q) for Aquifer UNR-1, Aquifer UNR-2 and Aquifer UNR-3 are 1146.70, 1691.02 and 16.97 km3 respectively. Thus, there is a difference in recharge to the tune of 1411 hams i.e. about 24% less recharge compared to the results obtained by the aquifer based methodology as per GEC (2015) guidelines. When the new recharge values are used in the GEC 2015 methodology a scenario close to reality emerges in the Nira River basin which proves the efficacy of the new methodology.

The Chhattisgarh state covers a total geographical area of about 135192 Sq. Km with subtropical climate, characterized by extreme summer and moderate winter having average rainfall of about 1300 mm. Physiographically, the area is characterized by three distinct landforms namely Bastar plateau in the South, the plain of Mahanadi river and its tributaries in the central part and the hills of Chhotanagpur plateau in the northern region. The major river basins in the state are Brahmani, Godavari, Ganga, Mahanadi and Narmada . The total catchment of these river basins is about 13559 kilometers. The Mahanadi Basin is the largest basin covering an area of about 76150 square kilometers out of 141589 square kilometers, nearly 4.3 percent of total geographical area of the country. Chhattisgarh has 2 percent population and 3.2 percent of total surface water resources of the country. The utilizable surface potential in the state if properly harnessed can irrigate about 4.3 million hectares area against the existing potential of 1.38 million hectare. Due to various anthropogenic activities, urbanization, industrialization etc, the quality and quantity of water have been adversely affected. The rivers Hasdeo, Indravati, Kharun, Apra etc. are polluted due to industrialization and urbanization in various parts of the Chhattisgarh. To check the pollution, proper management of solid/liquid waste of various industries is needed. Beside these, use of biofertilizers instead of chemical fertilizers, pesticides etc should be promoted. Effective water management strategies combined with watershed treatments like soil conservation, afforestation, desilting of rivers, rainwater harvesting etc are needed to maintain the health of the river basins of Chhattisgarh. The Jal Shakti Abhiyan started by the Government of India is a highly welcome move in this direction.

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.