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Soil, one of the non-renewable resources on this planet, is being depleted at an alarming rate due to various anthropogenic activities. The effect of soil erosion could range from on-site ecosystem fragmentation to off-site reservoir storage capacity loss. Though soil erosion is caused by various agents such as wind, water, etc., water erosion is the major type. Heavy rainfall during the monsoons and the relatively thin cover of soil over the bedrock aggravates the damage potential of this form of erosion in the state of Kerala, India. Water-induced soil erosion in the Bharathapuzha river basin in Kerala, which is blessed with cultivable land resources and intensive agricultural activities, has been undertaken for quite long and has started impacting agricultural activities, drinking water supply, and reservoir storage capacity in the basin. In this background, this study was taken up to assess the effects of climate and land use–land cover dynamics on soil erosion in the Bharathapuzha river basin over the last three decades. Soil erosion from the river basin was estimated by the Revised Universal Soil Loss Equation (RUSLE), and these estimates were verified with the observed sediment load in the Bharathapuzha river at the Kumbidi river gauging station. The storage capacity loss of some of the reservoirs located in the river basin, estimated by the Integrated Bathymetric Survey (IBS), was compared with the likely storage capacity loss of these reservoirs estimated based on soil erosion from the catchment areas upstream. Soil loss from the river basin for a future period was predicted using projections of future climate under two Representative Concentration Pathways (RCP 4.5 and RCP 8.5) from four regional climate data experiments and future land use–land cover. Annual soil loss estimation maps for 2020 and 2035 under RCP4.5 and RCP8.5 reveal the urgent necessity to plan and implement soil conservation measures in the erosion hotspots, especially in the Malampuzha, Anamala, and Attapady sub-basins. [ABSTRACT FROM AUTHOR]

This study quantifies the erosion of the Chennai coast in India and predicts how the shoreline will recede in the future. Previous studies in this region have reported erosion rates varying anywhere from 2 to 8 m/y. Such a high level of inconsistency in reported rates has hindered effective and sustainable coastal management. The research reported in this paper addresses this issue, using mapping data from 1904, 1974, 1996, and 2002 to estimate, by linear regression, the shoreline recession. The 10 km stretch of coast N of the fishing port at Chennai is repeatedly threatened during the NE monsoon, and as the process continues, the existence of a vital road link (the east-coast highway) is challenged by the fury of the waves. It is estimated that 260 ha of land has been lost between 1893 and 1955 and that 30 ha was destroyed by the sea between 1980 and 1989. Overall loss between 1893 and 1989 has been estimated in the order of 350 ha. The cost of land alone lost to the sea is in the order of US$40 million. The N Chennai coast has thus become volatile and is in need of immediate relief measures for the upkeep of the coastal region. Predictions for the next 250 years were then undertaken using a variety of techniques ranging from a process-based numerical model (Soft Cliff And Platform Erosion) to geometric approaches (including historical-trend analysis, the modified Bruun model, and Sunamura's shore platform model. The mean historic rate of erosion in the Chennai region is 1.11 m/y (60.15 m/y), significantly less than previously reported, though still very high. Subsequent predictions were used to identify a series of significant economic, ecological, and social features at risk, and to estimate when they will be lost to erosion if left unprotected. [ABSTRACT FROM AUTHOR]