This document provides an overview of environmental monitoring efforts in the Sundarbans region of Bangladesh. It discusses key drivers impacting the ecosystem like reduced river flow, shrimp farming, and sea level rise. Data is collected on rainfall, water levels, salinity, sediments, river flow, water quality, and land changes. Monitoring shows declining freshwater flow, increased salinity intrusion, sedimentation, and siltation. Modeling explores options to mitigate impacts through increased freshwater release and managing sea level rise. The Sundarbans is experiencing degradation due to reduced Sundari tree cover, fisheries decline, agricultural impacts, and increased arsenic in groundwater.

1. ENVIRONMENTAL MONITORING OF THE
SUNDARBANS: BANGLADESH PERSPECTIVE
Abu Saleh Khan
Deputy Executive Director
IWM, Bangladesh

3. Farakka
Barrage

4. N
North Central
• Area - 40,500 sq km North West North East
• Population - 30 million
Farakka
• 62% land cultivable
Barrage
South
North Central
• 10% Forest, Sundarbans Centra
• Only remaining habitats
for the Royal Bengal Tiger South West
South
Central
South West
Sundarbans
CAM
Bay of Bengal
Bay of Bengal

5. Driving forces on the ecosystem
REDUCED RIVER FLOW
Agriculture
Shrimp farming
- -
Manure
- -
- -
POLDERING
URBAN AREAS
FARMING
(Groundwater)
Development in the upstream catchment & freshwater flushing
Micro-topographic changes due to deposit of sediments carried by rivers or tidal currents
Industrial, maritime and agricultural pollution
MONGLA PORT
KNM
SUNDARBANS
Sea level rise due to global warming
Extreme wave attack due to cyclone and tidal surges

6. Declining Ganges Distributaries
Salinity
Top Dying of Sundarbans
Groundwater
Fisheries
Agriculture
Desertification
Channel Siltation

7. Mathabhanga offtake Chandana now
closed inland river
Arial Khan-Buriswar
J am una Rive r
Ga n
ges
Riv
er
System
r
Go
iv e
r ai
R
Ri
hna
ve
Ch
r
eg
an d
rM
Ku
na
ma
pe
Pa
rR
Up
R
i ver
d
iv e
m
Na b
a
a gan
r
Ri
ga R
ve
r
Gorai-Passur/Sibsa Gorai-Madhumati
System Baleswar System

8. J amuna Riv er
Industrial units suffered a
progressive damage due to Ga
ng e
sR
ive r Crop damage and
increased corrosion
r
Go
ive
ra
yield reduction
aR
iR
iv
g hn
Ch
er
an
Me
dn
Ku
pe r
m
aR
ar
Pa
R
Up
iver
dm
ive
Na b
a
a
r
g an
Ri
ga R
ve
r
River water turned
impotable
Industrial operation needed
to carry fresh water from a
long distance Increased water borne
diseases
Top-dying of Sundari trees Degradation of public health

9. Increased salinity and
associated sedimentation
has raised the river banks.
Raised river banks resulted
in permanent bowl-shaped
depressions inside the forest
Root Zone
Nuematophores are exposed
to extended period of
inundation resulting in top-
dying of trees

10. Static water table dropped down to 23 ft(7.01m), which caused
• High pumping cost
• Saline intrusion in shallow water table
• Effect on surface water treatment plant
• Now surfaced ARSENIC pollution in groundwater

11. Arsenic
59 out of 64 districts are affected

12. Fish catch reduced:
• Ganges by 88%
Hilsha fish totally absent
• other rivers by 90%
• Beels by 31%
Total loss of Tk. 4 Billion
Already some local species of fish: Sarputi, Nandai,
Aeer, Belemach are no more available

13. Salinity at Khulna
20
15
Salinity (ppt)
10
5
0
Febraury March April May
Date
Measured 2000 Measured 1999 1989 1990
1991 1992 1993 1994
1995 1996 1997 1998

14. Water supply to G K Project drastically reduced
Implementation of Mathabhanga, Baral Basin and
North Rajshahi Irrigation Project suspended

15. Decrease in surface
water enhances
Desertification
Increased moisture deficiency
down to even wilting point and
added soil salinity result in
severe damage to soil fertility

16. About 1/4 th of the country
suffer water stress in dry season

17. “When only water is diverted at
upstream point with no sediment,
downstream reach undergo
severe morphological imbalances
and siltation occurs randomly”
Number of islands increased
in the Ganges river from
14 to 24 between 1973 and 1996

18. Heavy Siltation
Moderate Siltation
Slow Slitation

19. P W
Hydro-Morphological Aspect
14
13
Hardinge
W a t e r L e v e l ( m
Bridge 12
• Monthly discharge, Jan-May reduced by 25%
• Monthly discharge, Jul-Sep increased by 8%
11
10
GK • Min. WL dropped from 6.98m to 5.34m PWD
Intake 9 1960s
8
• Post-monsoon recession reduced from 4 to 2 months
7
6
Recent
5
0 30 60 90 120 150 180 210 240 270 300 330 360
Days (from 1 April)
Talbaria
Selaidha
L e v e l ( m , P W D )
15
13
Kushtia
Max. WL at Talbaria
11 Gorai Rail Bridge
9
Bed Level at Gorai Offtake
7
5
Min. WL at Talbaria
3
1964 1968 1972 1976 1980 1984 1988 1992 1996
18 Feb 1997 Year

20. • Rainfall: 5 locations
Data Collection under SBCP
• WL: 15 locations
• Salinity: 26 locations
• Sediment: 1400 nos. at 15
place
• River flow: 15 places, 1 – 3
rounds
• Water Quality: 10 parameters
at 16 pl
• Detailed Study: at 3 pilot
areas
• Land topography: at 3 pilot
area
• River Sections: at 178
locations
• Secondary: collected from
1991 onward

21. Data collection inside the Sundarban
Inundation of forestland Fall velocity measurement
Siltation on forestland River water level

22. Seasonal Fluctuation of Water Level
East West

23. Distribution of Rainfall in the Forest Area 2002
Mongla Supati Hironpoint Jhalia Notabaki
1200
1000
Rainfall in mm
800
600
400
200
0
May Jun Jul Aug Sep Oct Nov
Month

24. Seasonal Salinity variation During 2002
Salinity observation during 2002
30
25
20
15
10
5
0
4/1/02 5/3/02 4/5/02 3/7/02 1/9/02 31/10/02 30/12/02
Date
Supati Nalianala Hiron Point Notabaki

25. Salinity Distribution in
September 2001

26. Salinity Distribution in
March 2002

27. Salinity Distribution in
April 2002

28. Salinity Distribution in
May 2002
Non Sundari Area

29. Impact on Salinity Due to the Gorai Dredging

30. Monitoring of Water Quality Parameters
 Dissolved oxygen (DO)
 Biochemical oxygen demand (BOD)
 Chemical oxygen demand (COD)
 Ammonia as NH3-N
 Ammonium as NH4-N
 Nitrate as NO3-N
 Total phosphate as PO4-P
 Mercury (Hg)
 Chromium (Cr)
 Lead (Pb)
 Oil and grease

31. BOD Concentration observed during 2002
Monthly average of obseved BOD during 2002
25
20
BOD in mg/l
15
10
5
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Eastern Part Western Part
One sample with erroneous result has been excluded

32. Monthly Average of Observed DO value
Monthly average of observed DO (Random Sample)
during 2002
while profiling along channels during 2002
7.00
6.00
5.00
DO in mg/l
4.00
3.00
2.00
1.00
0.00
Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Total Sample: 1140 Minimum Allowable Limit: 5

33. Pb Concentrations: Eastern Sundarban
0.25
0.2 Harbaria
Harintana
Pb (mg/l)
0.15
Dudmukhi
Shwarankhola
0.1
Jafa
0.05 Mrigamari
0
Jan'02
Feb'02
Jun'02
Jul'02
Jan'03
Mar'01
Mar'02
Oct'02
Apr'01
Apr'02
Sep'02
Nov'01
May'02
Aug'02
Nov'02
Dec'02
Months

34. Pb Concentrations: Western Sundarban
Nalianala Arpangasia Bal Malancha Dingimari Kaikhali Kobadak
0.25
0.2
0.15
Pb (mg/l)
0.1
0.05
0
Jul'02
Jun'02
Aug'02
Jan'02
Feb'02
Sep'02
M ay'02
M ar'01
M ar'02
Nov'01
Apr'01
Apr'02
Oct'02
Dec'01
Months

35. Erosion/Sedimentation of rivers inside
the Sundarban

36. Patakata Khal, Chainage 0.81km
4
0
-4
Level, m
-8
-12
-16
-20
0 50 100 150 200 250
Width of the River, m
Surveyed in 2000 Surveyed in 1995
Erosion of river bank

37. Bhola River , Chainage 39.31km
2
Level, m
-1
-4
-7
0 100 200 300 400
Width of the River, m
Surveyed in 2000 Surveyed in 1995
Siltation on river bed

38. Selagang River, Chainage 40.67km
2
-3
Level, m
-8
-13
-18
-23
-28
0 200 400 600 800 1000
Width of the River, m
Surveyed in 2000 Surveyed in 1995
Erosion of river bed and bank

39. FLOODING IN THE SUNDARBAN

40. Inundation in Jangra Pilot
Area at high and low tide

41. Inundation in Jangra Pilot
Area at high and low tide

42. Inundation in Jangra Pilot
Area at high and low tide

43. SALINITY VARIATION WITH
UPSTREAM FRESH WATER FLOW
AND SEA LEVEL RISE

44. Existing dry period
salinity

45. Op1: Minimum 100 m3/s
in Gorai River

46. OP2: Minimum 200
m3/s in Gorai River

47. Op3: Minimum 200
m3/s in Gorai & 50 m3/s
in Kobadak, Hari,
Harihar & Betna

48. Op4: 50 cm Sea level rise

49. Long profile of maximum salinity concentration along Pussur-Rupsa
river system for different option scenarios
Maximum Salinity in March '02 for different Options
(River: Rupsa-Pussur)
30
25
Hiron Point
Mongla
20
Salinity(ppt)
15
Khulna
10
Bardia SUNDARBAN
5
0
0 20 40 60 80 100 120 140 160 180 200
Distance from Bardia (km )
BASE op-1 op-2 op-3
Op1: minimum 100 m3/s in Gorai
Op2: minimum 200 m3/s in Gorai
Op3: 50 m3/s in Kobadak, Hari, Harihar and Betna in addition to Op2

50. Mongla (Pussur-16.84 km)
7
6
5
Salinity (kg/m 3)
4
3
2
08-Feb-02 10-Feb-02 12-Feb-02 14-Feb-02 16-Feb-02 18-Feb-02 20-Feb-02 22-Feb-02
Tim e
Base Option-1 Option-2 Option-3
Op1: minimum 100 m3/s in Gorai
Op2: minimum 200 m3/s in Gorai
Op3: 50 m3/s in Kobadak, Hari, Harihar and Betna in addition to Op2

51. NOTABAKI (JAMUNA_35.57)
24
23
22
21
Salinity (kg/m )
3
20
19
18
17
16
15
23-Feb-02 25-Feb-02 27-Feb-02 1-M ar-02 3-M ar-02 5-M ar-02 7-M ar-02 9-M ar-02 11-M ar-02 13-M ar-02 15-M ar-02
Time
Base op-4 op-5
Increase in salinity at Notabaki due to sea level rise (Op4: 50 cm SLR &
Op5: 20 cm SLR)

52. Result of Hydrodynamic Model Showing the impact of Re-opening of Khorma Khal
Bhola River , Chainage 39.31km
Cross-section of Bhola River in 1995 and 2000
2
Level, m
-1
-4
-7
0 100 200 300 400
Width of the River, m
Surveyed in 2000 Surveyed in 1995
Proposed Bed Level Under Option Scenario
4
2 BASE BED-PROFILE
Note: Before drawing any 0
Level(m/pwd)
conclusion, this result obtained -2
from 1-D hydrodynamic model -4 OPTION BED-PROFILE
-6
should be verified with that of a
-8
sediment transport model (under
-10
development at present) 0 10 20 30 40
Chainage(km)
50 60 70 80
BASE OPTION-1

53. Result of Hydrodynamic Model Showing the impact of Re-opening of the
Khorma Khal
COMPERISON OF DISCHARGE AT CHAINAGE 23 KM
COMPARISON OF WATER LEVEL
150
3.5
Change in Flow Volume 3
Change in Water Level
100
2.5
WATER LEVEL (m.PWD)
50
2
DISCHARGE (M 3/S)
base Q23km
1.5
0
Option Q23km
1
-50
0.5
-100 0
-0.5
16/9/01 17/9/01 18/9/01 19/9/01 20/9/01 21/9/01 22/9/01 23/9/01 24/9/01 25/9/01 26/9/01
-150
0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00
16/9/01 17/9/01 18/9/01 19/9/01 20/9/01 21/9/01 22/9/01 23/9/01 24/9/01 25/9/01 26/9/01
0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 TIME
TIME
COMPARISON OF VELOCITY
Base Option 1.5
Change in Flow Velocity
1
Note: Before drawing any 0.5
conclusion, this result
Velocity(m/s)
0
obtained from 1-D
-0.5
hydrodynamic model should
-1
be verified with that of a
-1.5
sediment transport model) 16/9/01 0:00 18/9/01 0:00 20/9/01 0:00
Time
22/9/01 0:00 24/9/01 0:00 26/9/01 0:0

54. [meter] Water Quality Modelling
495000.0
490000.0
485000.0
480000.0
475000.0
470000.0
465000.0
460000.0
455000.0
450000.0
445000.0
DO mg/l
440000.0
435000.0
430000.0
425000.0
420000.0
415000.0
410000.0
405000.0
400000.0
380000.0 400000.0 420000.0 440000.0 460000.0 480000.0 500000.0 520000.0
[meter]
Modelled DO level on 17-8-2001 03:00 (Monsoon) in the Forest area

55. [meter] Water Quality Modelling
495000.0
490000.0
485000.0
480000.0
475000.0
470000.0
465000.0
460000.0
455000.0
450000.0
445000.0
DO mg/l
440000.0
435000.0
430000.0
425000.0
420000.0
415000.0
410000.0
405000.0
400000.0
380000.0 400000.0 420000.0 440000.0 460000.0 480000.0 500000.0 520000.0
[meter]
Modelled DO level on 09-12-2001 19:00 (Post-monsoon) for the Forest area

56. [meter] Water Quality Modelling
495000.0
490000.0
485000.0
480000.0
475000.0
470000.0
465000.0
460000.0
455000.0
450000.0
445000.0
DO mg/l
440000.0
435000.0
430000.0
425000.0
420000.0
415000.0
410000.0
405000.0
400000.0
380000.0 400000.0 420000.0 440000.0 460000.0 480000.0 500000.0 520000.0
[meter]
Modelled DO level on 28-6-2001 01:00 (Dry) for the Forest area

57. SWIMS
Sundarban Water Information Management
System

60. Achievement at a glance
Comprehensive data collection on water level, salinity,
sediment, discharge and water quality
Introduction of hydrological data collection on the forestland
Improvement of Hydrodynamic and AD Model
Introduction of non-point load assessment and Development of
Water Quality Model (indicative)
Application of HD & AD model for development of different
option scenarios
Development of SWIMS database and incorporation of
available data and maps prepared

61. Unfinished Tasks of SBCP
• Inundation/siltation study on forest land at more areas
• Improvement of HD model incorporating additional channels/creeks and
updated x-sections
• Improvement of Salinity & WQ model to simulate scenarios with more
confidence
• Development of Cohesive Sediment Transport Model to study sedimentation
process
• Establishment of Bench Mark at Southern Boundary Stations
• Exploring possibility of increasing flow in the western river system- Ganges
Barrage Option

62. Thank You