2018 Post Flood Groundwater Scenario of Kerala: A Critical Analysis

Gujarat Alluvial plains are well known for prolific aquifer system but due to overexploitation of groundwater in North Gujarat districts, the ground water levels have shown a declining trend, which entails higher water lifting cost in addition to the increasing investment in deepening of wells. As natural recharge of groundwater is not commensurate with groundwater extraction, the groundwater levels have dipped more than 190 m below ground level at some places of North Gujarat. In such areas, it is felt that artificial recharge of groundwater has much scope in water conservation and augmentation. Central Ground Water Board (CGWB) has given a new dimension to the groundwater sustainability in North Gujarat through harvesting of the surplus runoff and storing the same in the sub-surface reservoir adopting artificial recharge techniques.The present paper deals with the various activities undertaken by the Central and State Governments to arrest the groundwater level from further decline and also maintain the quality of groundwater. Based on the Pilot studies in the UNDP assisted project during the years 1980-85 in the Gujarat State, CGWB has advocated for artificial recharge of groundwater by spreading channel and injection methods to counteract the impact of overexploitation in the North Gujarat. In the Central Sector Scheme (CSS) of Ministry of Water Resources (now Ministry of Jal Shakti, Department of Water Resources, River Development & Ganga Rejuvenation), Government of India, demonstrative artificial recharge structures have been constructed by the State Government in the Saraswati river bed at Madhu Pavdi check Dam in Sidhpur, Patan district, Due to non availability of surplus water in the North Gujarat Region, Government of Gujarat launched an ambitious inter basin water transfer program known as Sujalam Sufalam Yojana. In this Sujlam Suphalam Yojana one major unlined recharge canal named as Sujlam Suphalam spreding canal has been constructed with a length of 332 km from Mahi to Banas River which diverts of surplus flood waters of Kadana Reservoir and the Narmada to the water deficit areas. In the Lift Irrigation scheme, nine reservoirs of North Gujarat region are planned to be filled by laying pipelines utilising surplus flood water of Narmada.

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.

The high reliability of rural and urban settlements on groundwater in India and the individualistic nature of groundwater usage make groundwater management and governance extremely challenging. Groundwater resources development in India, even today, has progressively become synonymous with increasing the accessibility of the resource through more and more sources and meeting the growing demand through the infrastructure of distribution. Management of groundwater becomes selflimiting when the focus is on exploration for new sources, without understanding resource behaviour. On the other hand, experience has shown that bringing aquifers to the centre stage of groundwater management is important. The concept of aquifers changes the way in which communities begin to perceive groundwater and becomes the first step in developing socioecological resilience to groundwater-related vulnerability. Building resilience to groundwater-related vulnerability further includes developing a governance mechanism that strikes a balance between supply management and demand regulation through an understanding of the resource, i.e., the aquifer.Aquifer systems in India are highly diverse and complex because of the variation in their inherent properties such as storativity, transmissivity and groundwater quality. Aquifer vulnerability is a consequence of not only how the rampant exploitation and contamination of groundwater occur, but also how different aquifers react to these fluxes. Moreover, irrespective of the scales of groundwater accumulation and movement, micro-level analysis of aquifers becomes imperative because of the atomistic nature of groundwater access and use. A systematic hydrogeology-based approach that requires delineating aquifers, understanding the dynamics of groundwater and mapping the demand and dependence of community on the resource holds the key to decentralized groundwater governance in India. Such an approach can be undertaken through participatory monitoring, decision support and action.The inherently heterogeneous nature of aquifers and communities in western and central India demand a strategic application of mapping, characterizing and managing local aquifers through a participatory groundwater management protocol. This nuanced approach beginning with aquifers as both a resource and a system, ensures equitable, efficient and hence, the sustainable management and governance of aquifers in this region.

In western India, the states Goa, Gujarat, Maharashtra and Rajasthan having area of 0.11%, 5.97%, 9.36% and 10.41% of India respectively have 0.24%, 6.83%, 13.48% and 4.52% of the total population of the country. The area, except Goa which records high precipitation, receives moderate rainfall. Arid conditions prevail in north Gujarat and major part of Rajasthan. The utilization pattern of ground water is uneven across the region resulting in ground water stressed conditions and over exploitation in some parts, particularly the arid regions and sub-optimal ground water utilization in others. Water level varies widely being very shallow in the southern part and deep to alarmingly deep in the northern part, having deepest water level of the country in Bikaner district of Rajasthan. Water quality is of concern in the major parts. In considerable areas, some chemical constituents exceed the permissible limit for drinking water, and large patches with brackish to saline water are encountered in Rajasthan and Gujarat. Sporadic occurrences of Fluoride and Nitrate in ground water exceeding the permissible limit for drinking water are spread almost throughout the region which necessitates cautious use of ground water in these areas for drinking purposes. The stage of ground water development is 37%, 68% and 54% in Goa, Gujarat and Maharashtra respectively. In Rajasthan, the stage of ground water development is 140% and 164 out of 248 ground water assessment units are overexploited and 23 ground water assessment units in Gujarat are over exploited. This requires immediate judicious intervention without which some areas will not be able to meet even the drinking water needs. Groundwater withdrawal requires to be strictly regulated so that it does not exceed the annual recharge and also that it does not disturb the hydro-chemical balance. Alarming declines in groundwater levels warrant immediate attention for taking-up of recharge schemes to arrest further decline and augment the groundwater resources. In areas of scanty recharge, ground water should be allowed only for drinking water purposes. In other areas, along with water conservation and ground water augmentation measures, demand side management using micro irrigation techniques and change of cropping pattern etc should be religiously adopted.

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.

Palghar, Thane, Raigad, Ratnagiri, Sindhudurg and Greater Mumbai districts of Maharashtra form the Konkan Coastal belt of Maharashtra. In the coastal areas the immediate effect of high groundwater development is often sea water intrusion. Although there were sporadic studies by earlier workers (Umrikar et al., 2007, Gupta et al. 2010) into some reported isolated cases of seawater intrusion in the coastal areas, this has been a maiden attempt to decipher the extent of seawater intrusion in the entire coastal tract of Maharashtra.The area is underlain by Dharwarian meta-sediments (Lower Precambrian age), Deccan Trap lava flows (Upper Cretaceous to Lower Eocene age), Laterites (Pleistocene age) and Coastal alluvial deposits (Recent to Sub-Recent age). Groundwater occurs under phreatic condition in the Coastal and riverine alluvium, laterites and weathered/fractured rocks. The area has been covered by systematic hydrogeological surveys, reappraisal Surveys and groundwater monitoring by CGWB. in these formations depth to water levels range from 0.6 m bgl to 8.07 m bgl. Groundwater is mildly alkaline with pH range of 6.9 to 9.0. Electrical conductivity ranges from 61 to 29370 ?S/cm at 25?C. Only two Samples from Dapoli in Raigad district show EC values higher than 3000 ?S/cm at 25?C. In general, water quality is good and suitable for domestic use and irrigation. In order to confirm the sea water intrusion, ionic ratios like Na:Cl, and Cl:CO3 + HCO3, were computed. From the analysis it is found that about 2 to 10 km wide coastal belt and the inland tidal backwaters are affected by salinity intrusion. It is revealed that about 55% of the analysed samples have indicated salinity ingress. The extent of sea water intrusion is more in the southern part progressively diminishing towards northern area. The maximum effect is observed in Sindhudurg district followed by Ratnagiri, Raigad, Palghar and Greater Mumbai.Over-exploitation of groundwater in pockets and diminishing seaward freshwater flow in the rivers are the major reasons for sea water ingression. Regulation of groundwater development in the coastal area and areas adjacent to estuaries, maintaining adequate stream flow, stopping of riverbed sand mining, construction of tidal regulators at suitable places and creation of fresh water barrier through rainwater harvesting and groundwater recharge are essential to control further sea water intrusion in the area.