Assessment of Shoreline Changes in the Period 1969-2010 in Watamuarea, Kenya

Abstract

Watamu coastlineis a major attraction site for tourist and also a source of income for the local people. However, the shoreline has been changing due to erosion. This study sought to find the trend of shoreline changes, and the factors attributed to the changes. Aerial photographs of 1969 and 1989 and a recent satellite image of 2010 wereused to digitize the shoreline.The Digital Shoreline Analysis System (DSAS) in ArcGIS environment was used to create transects and statistical analyses for the shoreline.Several GPS points were taken in October 2013 and 2014 during ground truthing following the High Water Mark (HWM). The 9.8 km long Watamu shoreline was divided in-to 245 transects with 40 meter spacing in order to calculate the change rates. The rates of shoreline change were calculated using the End Point Rate (EPR), Net Shoreline Movement (NSM), and Weighted Linear Regression (WLR) statistic in DSAS.