Instream Water Availability in the Sundarbans Mangrove Ecosystem of Bangladesh
Location
Logan Country Club
Start Date
3-28-2017 2:00 PM
End Date
3-28-2017 2:05 PM
Description
Instream water flow is crucial for the sustenance of an ecosystem. This study attempts to quantify the seasonal variability of instream flows of Sundarbans of Bangladesh which is the part of world’s largest Mangrove ecosystem. It is located at the interface of the Bay of Bengal and is grown on swamps of fresh and saline water. Unfortunately freshwater is depleting at an alarming rate due to diversions of upstream flows in the Ganges River together with low rainfall during dry season and irrigation and industrial water uses. The complimentary relationship method was used to calculate ET using meteorological data from 11 weather stations. Evapotranspiration and off-stream water use (irrigation, industrial and domestic) were used to calculate instream water flow. Flow duration curves (FDC) were used to assess the change of incoming upstream flow. Two treaties were in place to receive upstream water flow to Bangladesh through the Farakka Barrage. Flow data of the recent treaty period (1997-2015) for five major discharge stations were used as flows into the study area. Also 1 km resolution MODIS data of annual maximum green vegetation fraction (MGVF) cover were used to assess the spatial extent of Sundarbans’ mangrove region which is dependent on Ganges Flow. A large variation of around 83% is observed for instream water flow between wet and dry seasons. The flow analysis on Gorai river (1997-2015),the only major spill channel of the Ganges towards Sundarbans, shows 51% and 32% decrease in low and high flow threshold values, respectively from the pre-barrage period (before 1975). Dense vegetation fraction cover (>60%) is decreasing but not statistically significant. These background analyses will help to develop a comprehensive water management plan that can minimize environmental degradation and support ecosystem services of Sundarbans.
Instream Water Availability in the Sundarbans Mangrove Ecosystem of Bangladesh
Logan Country Club
Instream water flow is crucial for the sustenance of an ecosystem. This study attempts to quantify the seasonal variability of instream flows of Sundarbans of Bangladesh which is the part of world’s largest Mangrove ecosystem. It is located at the interface of the Bay of Bengal and is grown on swamps of fresh and saline water. Unfortunately freshwater is depleting at an alarming rate due to diversions of upstream flows in the Ganges River together with low rainfall during dry season and irrigation and industrial water uses. The complimentary relationship method was used to calculate ET using meteorological data from 11 weather stations. Evapotranspiration and off-stream water use (irrigation, industrial and domestic) were used to calculate instream water flow. Flow duration curves (FDC) were used to assess the change of incoming upstream flow. Two treaties were in place to receive upstream water flow to Bangladesh through the Farakka Barrage. Flow data of the recent treaty period (1997-2015) for five major discharge stations were used as flows into the study area. Also 1 km resolution MODIS data of annual maximum green vegetation fraction (MGVF) cover were used to assess the spatial extent of Sundarbans’ mangrove region which is dependent on Ganges Flow. A large variation of around 83% is observed for instream water flow between wet and dry seasons. The flow analysis on Gorai river (1997-2015),the only major spill channel of the Ganges towards Sundarbans, shows 51% and 32% decrease in low and high flow threshold values, respectively from the pre-barrage period (before 1975). Dense vegetation fraction cover (>60%) is decreasing but not statistically significant. These background analyses will help to develop a comprehensive water management plan that can minimize environmental degradation and support ecosystem services of Sundarbans.