Potentials of sibsa river

1. 7th International Conference on Civil Engineering for Sustainable Development
(ICCESD-2024), 7~9 February 2024, KUET, Khulna, Bangladesh
POTENTIALS OF SIBSA RIVER FOR DEVELOPMENT OF A NEW
PORT IN TERMS OF NAVIGABILITY
Presented By
Rezwanur Rashid- Assistant Engineer,Mongla Port Authority
Co-Authors
Motiur Rahman - Executive Engineer, Mongla Port Authority & Ph.D Student, KUET
Prof. Dr. Md. Shahjahan Ali – Department of Civil Engineering, KUET
Department of Civil Engineering
Khulna University of Engineering & Technology

2. INTRODUCTION
 The Pussur-Sibsa system is a
multichannel system within the
southwest GBD.
 It flows partly through the Sundarbans
and consists partly of a heavily
modified delta plain.
 Approximately 30 km from its mouth
the river diverges into the Sibsa River
(west branch) and Pussur River (east
branch).
Mongla Port
Akram
point
30km

3. INTRODUCTION
 The Mongla Port (MP) is situated on the
east bank of Pussur river, at around 80 km
upstream from Akram point.
 The Pussur river's depths were adequate
for an average of 8.5m draft ships at the
time of Mongla Port’s establishment.
However, after 1980, the depths were
drastically reduced.
Mongla Port
Akram
point
80 km
 Several dredging efforts had been made to restore the
navigability of the Pussur River since 1979. But none of
the dredging attempts could maintain an effective passable
channel because of the high siltation rates

4. INTRODUCTION
• Akram Point is the confluence
point of Pussur and Sibsa river.
• The cross-section at this location
on the Sibsa river shows that the
depth of the river is 34m CD
whereas in the Pussur river depth is
24m CD.
• Sibsa river is tidally very active
compared to the Pussur river in
terms cross-sectional area, depth
and tidal volume.
Akram point

5. INTRODUCTION
• Government of Bangladesh has established another sea port
on Ramnabad channel named Payra Port which is around 70
km east of Pussur-Sibsa estuary.
70km
Payra port
Pussur-Sibsa Estuary
Bay of Bengal
• The Port has an almost 75 Km long outer channel which is
too shallow for arrival of ships and a designed canal needs
to be dredged and maintained to a particular level that is
safe for passage.

6. INTRODUCTION
This presentation will demonstrate the suitability of Sibsa
river for development of new port in terms of Hydrodynamics
and Morphology of the river.

7. STUDY AREA
The study area focused on
 Pussur-Sibsa River system
Starting at Khulna on north
and Bay of Bengal on south.
 The Sundarban also falls
within the study area.
 Two types of tidal river system
were considered:
1. primary (Pussur and Sibsa)
2. connecting channels (tidal
channels linking primary
rivers)
 Mildly focus on hydrography
and dredging of Payra port.

8. METHODOLOGY
Analysis of hydrographic profiles of both primary
river.
Study of several reports to assess annual
maintenance dredging quantity.
Approximate cost analysis of dredging.

9. RIVER GEOMETRY
GBM Delta
Gorai River
Pussur-Sibsa
85%
Modhumoti-
Baleshwar
15%
(through
Nabaganga &
Rupsa)
175 km

10. RIVER GEOMETRY
Connecting Rivers Between Pussur and Sibsa
Solmari (Batiaghata)
Jhapjhapia (Pankhali)
Chunkuri (Dacope)

11. RIVER GEOMETRY
900
3000
2000
4500
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
1 2
Width
Width Comparison
Possur
Sibsa
Pussur
Sibsa
Dacope Akram Point
(m)
70
km

12. HYDRODYNAMICS
In comparison to Pussur River, Sibsa has
 More tidal activity
 Higher tidal volume
 Deeper bed level
 Faster tide propagation
 Faster approach speed of tide

13. HYDRODYNAMICS
-2
-1
0
1
2
3
4
5
5:00 7:00 9:00 11:00 13:00 15:00 17:00 19:00 21:00 23:00 1:00 3:00 5:00 7:00 9:00 11:00 13:00 15:00 17:00 19:00
Time
Water
Level
Nalianala
Mongla
Hiron Point
30 min
2 hr
1.5 hr
Propogartion of tide through Sibsa river is faster than Pussur and also the approaching
speed of tide through Sibsa river is faster than Pussur River. The parallel point of
Mongla in Sibsa river is Naliana, where tide reaches about 30 minute earlier than
Pussur

14. HYDRODYNAMICS
River Dry Season Discharge Monsoon Season Discharge
Spring Neap Spring Neap
Flood
(mill.m3)
Ebb
(mill.m3)
Flood
(mill.m3)
Ebb
(mill.m3)
Flood
(mill.m3)
Ebb
(mill.m3)
Flood
(mill.m3)
Ebb
(mill.m3)
Sibsa 186 196 100 109 305 258 306 215
Pussur 137 144.5 83 85 167.5 110 157 72
COMPARISON OF FLOW
• Average flow throughout the year:
 Sibsa river is 209.38 mill.m3
 Pussur river is 119.5 mill.m3
• Sibsa channel has 75% more flow than Pussur channel throughout the
year

15. MORPHOLOGY AND NAVIGABILITY
BED LEVEL
 Sibsa River about 20m-35m below CD
 Pussur River about 5m-20m below CD

16. MORPHOLOGY AND NAVIGABILITY
Thalweg of Pussur River
-35
-30
-25
-20
-15
-10
-5
0
0 20000 40000 60000 80000 100000 120000
Distance from Upstream [m]
Bed
level
[mCD]
Figure: Bed profile of the Pussur river along the thalweg line
Chalna
Joymonirgoal
5m-7m
15m-25m
Akram Point
<10

17. MORPHOLOGY AND NAVIGABILITY
Thalweg of Sibsa River
-35
-30
-25
-20
-15
-10
-5
0
0 20000 40000 60000 80000 100000 120000
Distance from Upstream [m]
Bed
level
[mPWD]
Figure: Bed profile of the Sibsa river along the thalweg line
Chalna
Constantly deep bed level
Akram Point
(20m-35m)

18. DREDGING AND COSTING
 In Pussur river five major dredging projects has taken
place from 1990 to 2023.
 The MPA has conducted capital dredging of 330
million m3 and maintenance dredging of 53 million
m3. Total expenditure was 10 billion BDT
approximately.
 To maintain the 7.5m-8m CD, About 5 million cubic
meters of annual dredging is required. Yearly
expenditure of this dredging will be 1.75 billion BDT
approximately.

19. DREDGING AND COSTING
 Most part of Sibsa river has sufficient depth for
movement of more than 10m draft ship
 Only the entrance of Pussur-Sibsa river has to be
dredged which is common for both Pussur and Sibsa
river. The dredging volume will be 1 million m3
approximately.
 Maintenance Dredging of inner channel will be
almost negligible compared to 4 million m3 of Pussur
river.

20. DREDGING AND COSTING
 In Payra port, The port area has sufficient depth to
accommodate ships with 10m draft but the outer
channel spanning around 75 km in length which
currently suffers from insufficient depth to address
ship arrivals.
 A channel must be regularly maintained to ensure a
safe passage for vessels.
 Approximately 9.75 million cubic meters of sediment
has been extracted from the outer channel in order to
create a canal with a width ranging from 100 to 125
meters. This excavation process has incurred a cost of
5 billion BDT.

21. CONCLUSION
 The operational and maintenance cost of Sibsa river will
be less than the existing Mongla port or Payra Port.
 The hydrodynamic and morphological features of Sibsa
river are in more advantageous status than Pussur River
or Ramnabad Channel.
 However, hinterland connectivity to be improved,
specially bridges over Chunkuri and Jhapjhapia river to
connect with Khulna city.