GIS based spatial decision support system for artificial recharge site selection for Dhaka city, Bangladesh

Dhaka is one of the most challenging megacities in regard to its water resources management. The population of Dhaka city is presently about 12 million and the growth trend indicates that by the year 2010 it would be about 15.5 million. This increase of population would create water supply demand of additional 42% of the present production, which has to be met either from the surface water sources or by groundwater sources. In the city, 411 tubewells are in operation now to supply water, which is about 82% of the total supply of Dhaka water Supply Authority. Due to huge extraction of groundwater, the groundwater level is decreasing rapidly (about 2-3 m/yr). Again, the tremendously polluted surface water sources are not suitable for water supply. In order to alleviate pressure on groundwater resources and to meet the water supply deficit, it is now urgently required to identify alternative sources of water and to investigate the environmental, social and economic feasibility. To facilitate work for the the decision makers, a decision support is therefore necessary, which will consider the geographic information of the water resources within the city. A brief pre-feasibility review of technical aspects clearly indicates that there is high potential for artificial recharge project implementation in Dhaka city. Extreme rainfall events during monsoon, large amounts of treated water, possibilities of imported water make the clear need for further analysis of artificial recharge project planning and management evident. This presentation will focus on the development of a GIS based spatial decision support system focusing on site selection for an artificial groundwater recharge project, considering all relevant surface (e.g. land use, slope, soil map) and underground (e.g., aquifer thickness, hydraulic conductivity, depth to groundwater, etc.) characteristics. In addition to site selection, the spatial decision support will consider also other water resources planning options (e.g. source of water, spatial variation of rain distribution etc.). The implimentation of this specific Decision Support System (DSS) into the water resources planning and management process is promising a new and innovative approach into water management of urban areas.
Prestation: GIS based spatial decision support system for artificial recharge site selection for Dhaka city.pdf1.7 MB