Estimation of impact of sea level rise on land and water resources when data is sparse - case of Colombo. Environment and ecology research

Abstract

This paper highlights investigation and the impacts on the changes in groundwater table caused by sea level rise due to climate change in Wellington New Zealand and translates it to possible impacts in Colombo Sri Lanka.

Similarly the possible loss of land due to elevated sea level rise has been investigated. In the past 100 years sea level raised on average by 0.2m in Wellington region and it is predicted that by the 2090 sea level will increase by 0.8 m and by 2115 almost 1m. Therefore an investigation has been carried out by developing a three-dimensional hydrodynamic numerical model. Numerical model was developed using comprehensive groundwater modelling package FEFLOW 6.1. Once the model was developed and calibrated, four scenarios were investigated. Scenario 1 assumed the increase of 0.5 m of the mean seawater level (MSL). Scenario 2, Scenario 3 and Scenario 4 assumed an increase of 1.0 m, 1.5 m and 2.0 m MSL respectively. The changes were compared in nine observation bores and the results are presented. Thereafter taking into consideration the variability of rainfall these estimations have been translated for Colombo. The loss of land is also analysed for those four cases. The loss of the land due to sea level rise was estimated by using ArcGIS (ESRI, 2012). The affected area by the sea level is defined by the corresponding contour, 0.5 m, 1.0 m, 1.5 m and 2.0 m, and the coastline which corresponds to 0 m contour and the sea level at present day. Again these results have been translated to Colombo and presented.