DEVELOPMENT OF A GIS BASED MODEL TO EXPLORE SAFE WATER OPTIONS IN SOUTHERN COASTAL REGION

Abstract

Safe water scarcity is one of the most leading crises in coastal Bangladesh. Salinity intrusion in both surface and groundwater is alarmingly augmenting and creating acute drinking water and safe water paucity. This study was conducted to examine the existing condition of safe water availability in Mongla Upazila (3rd level administrative zone) of southern coastal area of Bangladesh based on both quantitative and qualitative approaches. Spatio-temporal variation of both ground and surface water quality parameters (EC, TDS, Cl-) was determined by the Inverse Distance Weighted (IDW) method of Deterministic model. IDW was proved to be effective to determine spatial variation of these parameters in Mongla. From the spatial distribution of EC, TDS and Cl-, it was revealed that areas within the acceptable limits were very negligible and temporal variation depicted that areas with higher concentration of these parameters increased substantially within the last 10 years. For depicting the availability of safe water at each union (4th level administrative zone) of Mongla Upazila, ranking based comparative analysis was carried out. Unions were ranked based on both quantitative and qualitative factors. This study considered water quality parameters as quantitative factors; and no. of households covered by tube well/tap water, no. of functioning PSFs, no. of RWHS, no. of functioning RO, presences of community based adaptation options and NGO activities were the selected six qualitative factors. From the spatial distribution, each water quality parameters were classified into five classes and given a rank on a scale of 1 to 5, where 1 meant very low and 5 meant very high availability of safe water. Based on water quality parameters, only Suniltala union showed moderate status and others showed low safe water availability. On the other hand, unions were provided rankings for six qualitative factors, which were found from the insights of FGDs and KIIs. Burirdanga union and Paurashava showed high availability of safe water which was mostly because ii of their geographic location (near the Mongla port); and socio-economic conditions and good connectivity with nearby developed regions. Chila and Sundarban, being located in the southern part of Mongla showed low availability of safe water and others showed moderate safe water availability. To resolve the acuteness of fresh water scarcity, community based sustainable options should be introduced by maintaining the integration between local government, NGOs and other relevant stakeholders. A total of 150 households were randomly surveyed from Mongla Upazila. After analyzing their responses, a community-based model was designed to provide safe drinking water for 50 households, which could be implemented in any place. After conducting in-depth field visit, FGDs, KIIs and questionnaire survey it seemed that usage of Rainwater Harvesting System (RWHS) and Reserve Pond (RP) could be good solutions for combating water salinity problems in the study area. RWHS and RP are very convenient and economical to install and maintain that will supply safe drinking water in a sustainable way.