An adaptive approach to monitor the Shoreline changes in ICZM framework: A case study of Chennai coast

Shoreline change study was carried out for 25 km long stretch of Chennai coast. Landsat TM (1990), Landsat ETM+ (2000), CARTOSAT-1 (2006), Resourcesat-1 (2008) and Resourcesat-2 (2012, 2013) satellite images were used as input dataset. Field survey was also carried out using Arc-Pad GPS instrument for 2011. Three methods i.e. End Point Rate, Linear regression Rate and Weighted Linear Regression were employed to calculate shoreline change rate for 1990-2013. While, EPR method is used to calculate the short-term analysis for 1990-1998 and 1999-2006. Study area was divided into four distinct zones. Totally 412 transects were generated with 50 m spacing and the length of each transects was 200 m. From the long term analysis, the high erosion was noticed on the northern side of the Thiruvottiyur region with a rate of more than 5 m/yr. Royapuram fishing harbour is noticed with an erosion rate of 4m/yr during the period of (1990-2012). 2 to 4 m/yr accretion was seen all along the marina beach. Whereas, south of marina beach, the places like Foreshore estate, Elliot beach and Thiruvanmiyur regions shows low erosion rate. From the analysis it clearly shows that the northern portion of the Chennai port is eroding and the southern portion of the port is accreting. Combined use of satellite imagery and statistical methods proves to be a reliable method for shoreline change analysis. Of all the statistical methods, WLR statistical method is found to be more reliable as it takes uncertainties and quality of datasets into account to calculate the rates of shoreline change.