The water resources in the coastal zone of the Ganges delta are largely shaped by tidal dynamics and trans-boundary flow/upstream flows, in addition to changes in natural, socio-economic and institutional systems. Agriculture-aquaculture systems in the coastal zone are largely dependent on the availability of fresh water, which is in turn governed by a number of external drivers. These dependencies are likely to be more pronounced in future. Yet existing knowledge of the anticipated effects of these external drivers on water availability, water management of polders and the health of the coastal zones is limited.
The Ganges project on ‘Assessment of the impact of anticipated external drivers of change on water resources in the coastal zone’ (G4) is working to identify the important external drivers that influence water resources, and assess the impact of these drivers on anticipated changes in drainage congestion, salinity intrusion, water availability and risk of inundation from cyclone-induced storm surges. Detailed, participatory analysis on salinity, water availability, storage capacity of drainage and irrigation channels in the polders, storm surge and drainage congestion have been carried out in three polders.
The project has found that the quantity of freshwater is likely to decrease due to changes in a number of external drivers, including increased water salinity due to inadequate planning and management of transboundary water resources. In some areas, the effects on polders may be more influenced by changes in transboundary flows than by climate change. Contrary to the commonly held perception that soil and water is saline during the dry season in the Barisal area of Bangladesh, the project has demonstrated that there is plenty of fresh water throughout the dry season and that investment in irrigation hast the potential to allow for increases in cropping intensity from one to three crops per year. The study also found that drainage is the main water management problem in the polder at present, and will likely continue to be so in the future.
The project is disseminating its findings through the distribution of present and future salinity zoning and water availability GIS maps to the Planning Commission of Bangladesh, water resources planning organizations, professionals in implementing agencies, communities and researchers.
This project will conclude in December 2014.
View all G4 outputs on CG Space.
Institute of Water Modelling, International Water Management Institute, Institute of Water and Flood Management, Bangladesh Water Development Board
Zahir-ul Haque Khan, email@example.com