The historical shoreline changes from 1980 to 2020 along the Manamelkudi coast is studied using toposheet, satellite time-series Landsat data, and observed data. An attempt is made to recognise possible factors which are responsible for shoreline changes and spit growth at south Manamelkudi coast (Palk Strait), Eastern part of Pudukkottai district, Tamilnadu. During 1980–2020, the regions showed distinct spatio-temporal variability, which is discussed in relation to spit evolution and shoreline changes. The study also generated a long-term (1980-2020) shoreline change statistics (EPR, LRR, SCE and NSM, WLR) using the Digital Shoreline Analysis System (DSAS) at every 150 m interval for the Manamelkudi coast covering 42 km, identified the erosion and accretion and divide the shoreline into different classes of erosion and accretion. Identified lengths of shoreline with high erosion, low erosion, stable, low accretion and high accretion are, respectively, based on LRR. The results indicate that spit evolution is predominant along the Manamelkudi coast, with the highest percentage of erosion and accretion.

The study of sedimentary characteristics and paleontology is very useful in assessing the past environment of a study area. The Karankadu estuary study area is considered to be one of the most ecologically diverse in the Ramanathapuram district of southern India. The sedimentological and recent foraminiferal assemblages were studied using a drill core from the estuary. Foraminifera analyses, grain size analyses, heavy mineral analyses and XRD maps were prepared for the present study. A total of 30 species were identified from the following suborders: Rotalina, Lagenina, Mollusca, Miliolina, and Textularina. Grain size analysis identified the substrate as mostly silty clay. Heavy mineral analysis identified 90% of light minerals and 10% of heavy minerals. In XRD analysis, quartz and feldspar appeared as major minerals and garnet, zircon, hypersthene, magnetite and ilmenite as minor minerals. The present study shows that the environment is more diverse due to its quiet character and less responsive to hazardous events such as floods and waves.

Drought is one of the recurring features of Indian agriculture, especially in the rain fed areas. It affects not only the national food security but also causes miseries to human life and live stock. The study area, i.e., Ramanathapuram district of Tamilnadu, India (Latitude 9°40′and Longitude 78°70′) has been affected consecutively for the last three years from 2015 to 2018 by drought, due to the failure of rainfall of northeast and southwest monsoons. So, the economic status of the area has declined due to the drought and the people from this district have migrated to other districts to improve their socio-economic status. This district has seven taluks, eleven blocks and four hundred villages. Major physiography units of the district are vast coastal plain, adjacent alluvial plain and a small area of buried pediments. The predominant geological formations are recent alluvium, and laterite followed by mio-pliocene Cuddalore Sandstone, upper cretaceous calcareous sandstone and proterozoic basement rocks. The total thickness of sedimentary rocks may be upto 3000 metre. The shallow aquifer in the district is severely affected by sea water intrusion and the inland salinity of marine sedimentary formations. Since the shallow aquifer is saline, paddy cultivation practices are generally being done through rain fed lake irrigation. According to the Central Ground Water Board report, the deeper groundwater aquifer in this district would give a continuous supply of freshwater. In order to develop agriculture activities and avoid drought management, the following steps are to be undertaken immediately. 1. River linking scheme of westerly debouching, i.e., Western Ghat Rivers in the Arabian Sea with the ephemeral rivers of the study area such as Vaigai, Gundar and Kottakkarai Rivers to improve the recharge of groundwater and prevent sea water intrusion. 2. Delineation of the depth of deeper fresh water in Tertiary and Cretaceous aquifer by sub-surface mapping study through 2D resistivity imaging depth profile study and borehole data. 3. Augmentation of engineering structures in the coastal area will prevent sea water intrusion in the shallow aquifer. 4. To improve the socio-economic status of the farmer and for drought management, a crop insurance scheme should be implemented for farmers. 5. Providing long term loans with subsidy facilities should be implemented for the construction of bore holes to improve crop production by getting fresh water from a deeper aquifer. 6. The study area is located nearer to the sea, so the large scale desalination plant system should be implemented by government organisation to get fresh water for improving agriculture practices.

The purpose of this study is to evaluate the quality of groundwater for drinking and irrigation in the Avudaiyarkoil block of the Pudukottai district, which is a drought-prone region. Samples were collected from 20 wells on January 2021 and analysed for the water quality parameters, such as pH, EC, TDS, Ca2+, Mg2+, Na+, K+, Cl-, HCO3, SO4, NO3 and F-. The analysis revealed that SO4 is the dominant ion followed by Cl-, HCO3-, Na+, Ca2+, Mg2+, K+, NO3- and F- with respect to the mean value 292>234>208.4>125>100>24.75>18>16.15>0.2. The analytical results were compared with WHO and BIS guideline values to know the groundwater potability and TH, TA, SAR, Na%, RSC, PI, MgC and KI were calculated using the analytical results to identify the suitability of groundwater for irrigation purposes.