PRESENT CONDITION OF MEGHNA RIVER

Presented by:

Md. Saiful Islam

Semester: M-1, Dept. of GEE

Shahjalal University of Science and Technology

Welcome

Introduction

The Meghna River is one of the most important rivers in Bangladesh,one of the three that forms the Ganges Delta, the largest on earthfanning out to the Bay of Bengal.

The lower stream of the Meghna is the drainage outlet of threeprominent river system named Ganges-Brahmaputra-Meghna (GBM)river system.

The total length of the river, from the starting point of Barak River tothe river mouth of lower Meghna, is about 930 km.

Major tributaries of the Meghna include the Dhaleshwari River, GumtiRiver, Dakatia River and Feni River.

The Meghna is the widest river among those that flow completelyinside the boundaries of Bangladesh. At one point near Bhola,Meghna is 12 km wide.

RIVER COURSE

The Meghna is formed inside Bangladesh by the joining of the Surma and

Kushiyara rivers originating from the hilly regions of eastern India

Down to Chandpur, Meghna is hydrographically referred to as the Upper

Meghna. After the Padma joins, it is referred to as the Lower Meghna.

At Ghatalpur of Brahmanbaria District, the river Titas emerges from Meghna

and after circling two large bends by 240 km, falls into the Meghna again

near Nabinagar Upazila.

In Daudkandi, Comilla, Meghna is joined by the great river Gomoti, created

by the combination of many streams. This river reinforces Meghna a lot and

increases the waterflow considerably.

The Dakatia River is also part of the river system which joins Meghna in

Chandpur.

RIVER COURSE (CONT..)

Meghna is reinforced by the Dhaleshwari before Chandpur as well.

When the Padma joins with the Jamuna River, the largest distributary of the

Brahmaputra, and they join with the Meghna in Chandpur District, the result in

Bangladesh is called the Lower Meghna.

After Chandpur, when the river has the combined flow of the Padma and Jamuna it

moves down to the Bay of Bengal in an almost straight line.

In her course from Chandpur to Bay of Bengal, the Meghna braids into a number of

little rivers including the Pagli, Katalia, Dhonagoda, and Udhamodi. All of these rivers

flow out from the Meghna and rejoin again at points downstream.

Near Bhola, just before flowing into the Bay of Bengal, the river divides into two main

streams in the Ganges delta and separates an island from both sides of the mainland. The

western stream is called Ilsha and the eastern one is called Bamni.

Map Showing the Meghna River

Map: CIA (1996)

MEGHNA BASIN

• Meghna basin is the part of the greater

Ganges-Brahmaputra-Meghna (GBM)basin.

• Total Area of this transboundary river

basin is 1.7 million square km.

• Area of Meghna basin is 82000 sq. km.

• Meghna basin covers partial land of

two countries, India and Bangladesh.

• The entire Meghna River is situated in

Bangladesh, while upper tributaries are

situated in India.

Meghna Basin

Area (sq. km.) % of S.E Asia

82000 0.4

Countries Included:

Name Area of

Country

in Basin

(sq. km.)

% of

Total

Area of

Basin

% of

Total

Area of

Country

Bangladesh 35000 43 24

India 47000 57 1

[Source: Frenken, 2011]

Map of GBM Basin

Meghna Basin Outside Bangladesh

Meghna basin outside Bangladesh,

known as Barak basin, covers the

larger part eastern India including

the partial area of Meghalaya,

Assam, Tripura, Mizoram,

Nagaland, and Manipur province.

[Map: India-WRIS]

Meghna Basin Inside Bangladesh Boundary

The total river system of Meghna

inside Bangladesh boundary,

including upper tributaries known

as Surma-Meghna river system. It

covers the northeastern and

southeastern Bangladesh.

[Map: Banglapedia]

Hydro-Meteorological Data

Variables Pre-monsoon

106m3/day

Monsoon

106m3/day

Post-monsoon

106m3/day

Precipitation 83.52 230.76 16.74

Evaporation 34.26 44.69 52.77

Discharge 6.47 4399.36 1556.37

[Source: Uddin et al., 2014; Palash, 2008]

Water Level

Location Mean Max. WL

(mPWD)

Mean Min. WL

(mPWD)

Upper Meghna 6.00 1.5

Lower Meghna 4.00 1

Physico-Chemical Characteristics of River Water

Parameters Right Bank Left Bank DoE (1997) Standard

Temperature (°C) 25.45 25.15 20-30

pH 6.85 7.48 6.5-8.5

TDS (mg L-1) 43.65 43.68 1000.00

EC (µS cm-1) 87.23 87.34 350.00

Turbidity (FTU) 14.97 11.61 10.00

DO (mg L-1) 6.97 7.64 6.00

BOD (mg L-1) 5.3 4.34 0.20

COD (mg L-1) 57.31 66.68 4.00

[Source: Hassan et al., 2015]

pH and OM in the Meghna River Sediment

Sampling Sites Mean pH Mean OM Max. pH Max. OM Min. pH Min. OM

Right Bank 7.17 2.26% 7.25 5.92 6.95 0.21

Left Bank 7.32 1.07% 7.56 2.19 7.04 0.62

OM = Organic Matter [Source: Hassan et al., 2015]

The result showed that pH was nearly same on the both bank but OM was

higher on the Right bank sediment.

The neutral to slightly alkaline pH, probably related to carbonate nature of the

sediment and the presence of organic matter can influence the accumulation of

heavy metals in the sediments.

Garbage Dumping in the Meghna River

Thousands of tons of industrial and

household wastes and garbage are

being dumped into the Meghna

River without treatment.

The photo on the left side shows the

dumping of garbage into Meghna by

Chandpur municipal authority.

[Photo: Dhaka Tribune]

Heavy Metals in River Water

Metals Right Bank Left Bank DoE (1997) Standard

(mg L-1)

Cd 0.0027 mg L-1 0.0033 mg L-1 0.005

Cr 0.0202 mg L-1 0.0520 mg L-1 0.05

Fe 1.09 mg L-1 0.9475 mg L-1 0.3-1.0

Mn 0.0124 mg L-1 0.0045 mg L-1 0.10

Pb BDL BDL 0.05

Ni BDL BDL 0.10

Zn 0.0357 mg L-1 0.0374 mg L-1 5.00

BDL = Below Detection Limit [Source: Hassan et al., 2015]

Heavy Metals in Sediment

Metals Right Bankmg Kg-1

Left Bankmg Kg-1

USEPA (1999) SQGmg Kg-1

Cd 0.2808 0.1698 0.600

Cr 35.7464 26.9322 25.00

Fe 1293.85 1266.496 30.00

Mn 411.7323 479.6334 30.00

Pb 12.6384 5.6684 40.00

Ni 74.4498 78.1162 16.00

Zn 96.6593 57.8557 110.00

USEPA = United States Environmental Protection Agency [Source: Hassan et al., 2015]

SQG = Sediment Quality Guideline

SALINITY

Salinity is the concentration of salt in

water, usually measured in parts per

thousand (ppt). In estuaries, salinity

levels are generally highest near the

mouth of a river where the ocean

water enters, and lowest upstream

where freshwater flows in.

The standard concentration of salt in

freshwater is variously defined as less

than 0.5 ppt dissolved salts.

Other standards are: brackish water:

0.5-35 ppt, sea water: 35-50 ppt, and

brine water: >50 ppt.

River

Portion

Season Salinity

(ppt)

Lower

Meghna

Estuary

Pre-monsoon 9.94

Monsoon 0

Post-monsoon 0

Mouth of

Meghna

River

Pre-monsoon 11.74

Monsoon 0.1

Post-monsoon 0.1

[Source: Uddin et al., 2014]

Salinity in Meghna River

Morphological Change of Meghna River

The Rivers of Bangladesh are generally very active in morphological terms.

Most of the rivers in Bangladesh are part of a large delta and represents as

such an unstable state in the morphological development of river systems.

A recent study conducted by Hossain et al. (2014) to investigate the river

bank change of Meghna river within a period of 30 years (from 1980 to

2000).

Study showed that, river bank of Meghna River have significantly displaced

by erosion and depositional activities.

Bank Line Change of Meghna River

[Image: Hossain et al., 2014]

Landscape

changes

caused by

erosion and

deposition

activities of

the Meghna

River in

Chandpur

district

[Image: Islam, 2015]

River Bank Erosion at Chandpur and Bhola

Photo: The Daily Star

Sediment Load of Meghna River

Suspended sediment load of Meghna River is 0.010 g/L which was

measured in 2007 at Bhairab Bridge point of main river channel of

Meghna (Rice, 2007).

Suspended sediment concentrations in the Meghna River vary

considerably from the Ganges and Brahmaputra rivers.

Concentration of suspended sediment load Ganges-Brahmaputra main

channel have been found o.531 g/L at Mawa (Rice, 2007).

Study that cited above found that, water of Meghna River was not the

typical muddy brown color, but instead had a greenish tint and was

slightly translucent.

Recommendations

Structural approach should be initiated to control the river

bank erosion at Chandpur and in confluence of Ganges-

Brahmaputra and Meghna.

Industrial wastes should be treated well before discharged into

the river.

Initiative should be taken to process municipal garbage before

dumping into the river.

References

Frenken, K (eds) (2012) Irrigation in Southern and Eastern Asia in figures. AQUASTAT Survey –2011, Rome: Food and Agricultural Organization of the United Nations.

Hassan, M et al. (2015) Status of Heavy Metals in Water and Sediment of the Meghna River,Bangladesh. American Journal of Environmental Sciences, 11 (6), pp. 427-439.

Hossain, S et al. (2014) A study on morphological change of Meghna River due to climatechange by using GIS map analysis. Proceedings of 2nd International Conference onAdvances in Civil Engineering 2014, 26-28 December, 2014 CUET, Chittagong,Bangladesh.

Islam, S (2015) Land Cover Change Detection Using Remote Sensing Technique: A CaseStudy of Chandpur District, Bangladesh. Academic Dissertation, SUST, Sylhet.

Rice, S K (2007) Suspended sediment transport in the Ganges-Brahmaputra river system,Bangladesh. Unpublished MS These, Dept. of Oceanography, Texas A&M University,USA.

Uddin, M M et al. (2014) Water, salt and nutrient flux through the lower Meghna River estuary,Bangladesh. Indian Journal of Geo-Marine Sciences, Vol. 43(2), pp. 280-283

Thanks to All

The End