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There are three Bars, one at the mouth of the Karnafuli River called the OUTER BAR and the second is the INNER BAR at 1.22 Nautical miles from the Outer Bar and the third is the GUPTA BAR at 4.63 nautical miles from the Outer Bar. The Approximate least depths at the Outer Bar, Inner Bar & Gupta Bar are 6.2m, 7.3m and 6.0m respectively from the Chart Datum (CD) i.e., from Indian Spring Low Water Level (ISLWL).
Depth at Jetty Berth ranges from 8m to 9.1m and at Moorings from 8.8m to 10.5m and above
Max. Velocity of Current Opposite Khal No: 10 is as Under:
Spring tides (S.W.Monsoon) 4.5 to 5.5 Knots.
Neap tides (S.W.Monsoon) 2.5 to 3.5 Knots.
Spring tide (Winter months) upto 3 Knots.
Neap tide (Winter Months) upto 2 Knots
Freshet Ebbs upto 8 Knots.
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Salinity at Sadarghat varies from 0.1 gms/ 1000c.c at low water to 0.2gms/ 1000c.c at high water during monsoons and from 2.5gms/1000c.c at low water to 16.5gms/1000c.c at high water during dry season.
Salinity at Patenga varies from 0.15gms/1000c.c at low water to 3.3gms/1000c.c at high water during monsoon and from 10gm/1000cc at low water to 27 gms/1000c.c at high water during dry season.
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The width of the navigational channel(5.49m. contour) varies from place. A minimum of 250m. channel width is maintained.
The weather in Bangladesh is largely governed by the monsoon. The prevailing wind directions are from South to South East during the months of April through September. After taking easterly direction for a while the wind turns to the northerly and north easterly directions, the later prevail from November to January. During the months of February and March winds turn via westerly direction back to the Southerly to south Easterly. Wind in excess of 20 Knots/5 B.F. prevails for 6 percent to time while those in access of 30 Knots/7 BF persists for about 0.1 percent of time during cyclones i.e. During the transition between monsoon and dray seasons in May, October and November.
The port of Chittagong experienced four severe Cyclonic water surge during the last 44 years. In 1960 & 1963 speeds recorded were 125 Knots Max. In 1970 and 1991 speeds were recorded 138 Knots max. and 180 Knots max. respectively.
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The tides are important for navigations as determine the possibility of crossing the shallow area between Kutubdia points and the Karnafuli entrance and the Bars within Port Limit.
The tides are semi diurnal with prominent diurnal effect.
The approx. Tidal Ranges at Patenga, Khal No. 10 and Sadarghat from Chart Datum (ISLWL - Indian Spring Low Water Level which is 1.673m below mean sea level) are as follows:
| At Petenga: |
1.5m.-5.5m. (above ISLWL) |
| At Khal No. 10: |
1.5m-4.8m. (above ISLWL) |
| At Sadarghat: |
1.2m-4.2m. (above ISLWL) |
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The waves are generally low shown distinct relation with the wind. Maximum wave heights over 2m were recorded only on a few days during the small parts of days. The wave periods vary between 3-4 seconds of waves of about 0.5m and about six seconds for waves of 2m. These are from an observation made by NEI (Netherlands Economic Institute) 1972--1977.
During the months May to October freshets are expected, Freshets are caused by the normal velocity of flow of edd tide augmented by flow of additional volume of water that drains into the river from the catchment area. Freshets are expected when rainfall intensity reaches 200mm in 24 hours.
Density of water varies at each turn of the tide. Masters are advised to obtain the Circular from the local agents and follow the instructions closely.
N.B. Karnafuli being a tidal river, it is essential for a vessel entering the Port to have six ropes aft for Mooning purposes. For maneuvering in the Karnafuli River the length (L.O.A) carry dry cargo and tankers with Oil is retricted to 186 metre (610 ft.). « Back |
