Impact of Upstream Interventions on the Morphology of the Ganges-Gorai River

1. 1
WELCOME

2. Gorai River
Impact of Upstream Interventions
on the Morphology of the
Ganges-Gorai
2
M Shahriar Sonet
ID-34
DHSM-2016

3. Ganges is the 2nd longest
river in the GBM basin
Sources of Ganges
Information on
Ganges & Gorai
River
Sources of Gorai
Discharge
Ganges Gorai
7,000 cumec
3
Gorai (Gorai-Madhumati: 261miles)
is one of the longest river in
Bangladesh

4. RIVER MAP
Figure 1: The Ganges & Gorai Rivers on map,
source: The Ganges water diversion: environmental effects and implications, Maminul Haque
Figure 2: Ganges river basin
source: Encyclopedia, Britannica

5. Flow volume
Natural & Human Interventions
&
their Impacts on the Ganges
1 2 3 4 Figure
Reference : The basics you can find anywhere 5 Steps To Successful Storytelling Published on April 5, 2014 Featured in: Marketing & Advertising

6. Changes in the Ganges River
&
its impact on the Gorai River
Erosion/acceleration
(ha)
Bangladesh India Total Change
(1980-1999)
Erosion 18,250 13,350 31,600
Acceleration 5,600 8,500 14,100
Net erosion 12,650 4,850 17,500

7. Continue..
Figure 4: Mean daily discharges of the
Gorai River at different periods
source: http://a-a-r-s.org/aars/proceeding/ACRS1999/Papers/WR99-8.htm

8. Changes in the planform of the Ganges River around
the Gorai off-take
Figure 5: Landsat TM images of dry season showing the
planform of the Ganges river around the Gorai off-take
source: The Ganges water diversion: environmental effects and implications

9. Changes in the Hydraulic regime of the Ganges
Post-Farakka period
When there was no treaty, i.e. during 1988-1996,
water levels in dry period were lower than when a
treaty was in effect i.e. , during 1975 to 1987
the morphological changes are noticed where the
river banks are composed of highly erodible
materials, i.e., at the downstream reach of the Gorai
in the immediate upstream of Borida.
Morphological change

10. Future of the Gorai River and Disaster
management perception
Aspects Period Effects
Planform 1975-1985
1986-1998
+
-
Severe upstream bank erosion along the right bank 1987-1992 +
Existence of water-sharing treaty 1975-1987(except
1976)
+
Absence of water-sharing treaty 1988-1996 -
Different aspects that have influenced the Gorai River flow
(1975-1996) in addition to the Farakka Barrage
*‘+/-‘representsanuncertainsituations
**Existingwater-sharingtreatywillexpirein2026

11. Different aspects that will influence the Gorai River flow
(2003-2030) in addition to the Farakka Barrage
Aspects Period Effects
Planform 2003-2010
2011-2030
-
+/-*
Severe upstream bank erosion along the
right bank
2003-2030 +/-
Existence of water-sharing treaty** 2003-2026 +
Existence /Absence of water-sharing
treaty**
2026-2030 +/-
* ‘+/-‘represents an uncertain situations
** Existing water-sharing treaty will expire in 2026

12. When a large scale human
interventions occurs it can modify the
system as rapidly as natural hazard.
This is what is probably happening to
Gorai River.
—Maminul Haque Sarker

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