Coastal vulnerability assessment of the predicted sea level rise in the coastal zone of Krishna–Godavari delta region, Andhra Pradesh, east coast of India

Abstract

The Krishna-Godavari coastal region in east coast of India has a 525.15-kmlong coastline with low-lying tidal mudflats, beaches, mangrove swamp, creek and tidal channels. Recently, the increasing frequency of tropical cyclones in the Bay of Bengal, i.e., Phylin and Hudhud in Andhra Pradesh coast, and the devastating impact of the 2004 tsunami in India increased the significance in assessing the vulnerability of the coastal lands to inundation and flooding, notably in the context of climate change-induced sea level rise. This study aims to estimate a coastal vulnerability index (CVI) for the coastal subregion of Krishna-Godavari delta and to use the calculated index to evaluate the vulnerability of 14 coastal talukas of the Krishna-Godavari delta region. This CVI is calculated by using four geological and three physical parameters characterizing the vulnerability of the study coastal region, including regional slope, coastal elevation, geomorphology, significant wave height, mean tidal range and relative sea level using different conventional and remotely sensed data. Using a composite coastal vulnerability index based on the relative risk rating of those parameters, each of the 14 coastal talukas was classified according to their vulnerability. The CVI results depict that coasts are least and most vulnerable to inundation, flooding and erosion of coastal lands where geological parameters are more efficient to CVI. The paper alerts to decision makers and planners to mitigate the natural disaster and manage the coastal zone and is a primary step toward prioritizing coastal lands for climate change adaptation strategies in the view of increased storminess and projected sea level rise.

A Systematic Review of Coastal Vulnerability Assessment Studies along Andhra Pradesh, India: A Critical Evaluation of Data Gathering, Risk Levels and Mitigation Strategies

“…The geomorphology of the CAP is very diverse and economically important due to several features such as the Krishna-Godavari river delta, which plays a huge role in agriculture activities; developed/urbanized coastal areas along Visakhapatnam and Machilipatnam port; and ecologically sensitive places like mangroves and mudflats. Pramanik et al (2016) [75] described the region as sensitive to muddy and soft sand and categorised the entire coast into two risk rates (higher and lower). Rao et al (2010) [73] used IRS P6 AWiFS (The Advanced Wide Field Sensor) data to map geomorphology and its risk rankings, showing that the Krishna-Godavari deltaic regions are highly vulnerable due to the presence of mud flats, mangroves and the beach ridge complex.…”

“…Basheer Ahammed et al (2016) [76] extracted coastal slope data from GEBCO (General Bathymetric Chart of Oceans) to identify that the lower southern part of CAP has steeper slopes, which leads to higher vulnerability as well as other risks. The available literature revealed different forms of data for coastal slope and its vulnerability mapping: Rani et al (2018) [67] used ASTER DEM (Advanced Spaceborne Thermal Emission and Reflection Radiometer Digital Elevation Model) data, while SRTM DEM was used by Pramanik et al (2016) [75] (both SRTM and ASTER DEM have a resolution of 30m for the Indian region). These studies further noted that CAP steep slopes are at high risk due to shoreline erosion and inundation due to storms.…”

How to Define Priorities in Coastal Vulnerability Assessment

“…Coastal regions worldwide provide important ecosystem services, such as fishing, aquaculture, tourism and high biological and ecological productivity. During the 20th century, increasing populations, urbanization and development activities have started altering littoral processes and thus the provisions of these services [1]. Although coastal zones represent a small part of the urbanized land, they are exposed to the continuous action of several factors, both natural and man-induced, operating on different time scales.…”

“…Some of the most relevant natural factors are: wave height and direction, wind, tide, sediment transport, sediment supply from rivers to sea, soil subsidence, relative sea level change, rainfall, frequency and intensity of extreme climate events, including storms. As well, among the main factors induced by man we can group: maritime constructions and coastal defence such as ports and barriers, which interfere with the dynamics of sediments [2]; construction of housing, industrial, recreational infrastructures; interventions in river basin management and regulation of watercourses to provide water resources for drinking, irrigation and industrial use, which induce alteration of vegetation and forest drainage [1].…”

Impacts of predicted sea level rise on land use/land cover categories of the adjacent coastal areas of Mumbai megacity, India

“…However, the assessment of climate change and its impact were examined on various aspects from different parts of India (NIO Report 2010, INCCA Report 2 2010, Solomon et al 2007). Shoreline change and coastal vulnerability in the context of sea level rise and anthropogenic activities are the major concern along the eastern coast of India (Pramanik et al 2015a, b). The coastal inundation and vulnerability due to Tsunami events were studied in the eastern part of India (Jaya Kumar et al 2005).…”