ASSESSMENT OF EROSION RISK POTENTIAL IN TERMS OF BANK MATERIAL PARTICLE SIZES AROUND 3KM UPSTREAM AND 3KM DOWNSTREAM OF HAJI SHARIATULLA BRIDGE ALONG ARIAL KHAN RIVER IN BANGLADESH

 

B. Roy^1*, S. Ferdhous², M. Moniruzzaman^2,3, F. Rukshana², S. M. A. Horayra⁴, M. K. Eusufzai⁵, K. R. Ahmed² and U. Saha²

 

¹Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author: (E-mail: bikashduet60@gmail.com)

²Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

³Institute of Water and Flood Management, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

⁴Office of the Director General, River Research Institute, Faridpur-7800, Bangladesh.

⁵Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

 

Abstract

River bank erosion is a recurring issue at monsoon in Bangladesh. Erosion expedites the river bank failure occurring among many of the river bank failure criteria. So, it is very much important to assess bank erosion of the river prior to the planning of bank protection works. Here an attempt has been made to assess the erosion risk potential at the left and right banks around 6.0 km of Arial Khan River. In this study particle sizes are analyzed and percentage of Clay, Silt and Sand has been found out. From the particle size analysis, it has been seen that the left bank of the Arial Khan River predominantly consists of sand particles, except for Khas Char Bachamara, where silt particles dominate. On the other hand, right bank of Arial Khan River dominates the Silt and Sand particle. The erodibility index is determined through Bouyoucos erodibility index and EIROM. From the erodibility index result of EIROM the soil erosion of the bank is categorized and observed that the left bank of Arial Khan River is very high to critical position in risk of erosion except 3.0 m depth of Khas Char Bachamara which layer sometime protects the bank from erosion. On the other hand, the right bank of Arial Khan River is high to critical position in risk of erosion. From this study a design engineer can be aware of the bank materials and predict erosion risk. However, it is recommended that a full geotechnical investigation is needed to prevent river bank erosion.

Keywords: Arial Khan River, Bank materials, Erosion risk potential, Particle sizes.

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QUANTIFICATION AND SPATIOTEMPORAL EVOLUTION OF TIDAL ASYMMETRY IN THE SIBSA-PUSSUR ESTUARY: A HARMONIC ANALYSIS APPROACH

 

M. N. Kadir^1* and T. Naher²

 

¹Department of Agricultural Engineering, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.

^*Corresponding Author (E-mail: mnkadir@sau.edu.bd)

²Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

 

Abstract

Tidal asymmetry in deltas, resulting from the interaction between astronomical tides and nonlinear tidal processes in shallow water, plays a crucial role in sediment transport within estuaries. Quantifying tidal asymmetry is vital for understanding the factors contributing to long-term morphological changes. This study applies the harmonic analysis method (T_tide) to examine the spatiotemporal evolution of tidal asymmetry in the Sibsa-Pussur (SP) estuary of the GBM delta, considering strongly variable river discharge conditions. Data required for analysis is collected from the results of a hydrodynamic model for 1978, 1988, 2000, and 2011. The study focuses on eight main tidal constituents (M2, M4, M6, K1, S2, O1, MS4, MSf). Tidal duration asymmetry and peak current asymmetry are determined, quantifying tidal asymmetry based on amplitude ratios and phase differences. The findings reveal that the SP estuary becomes increasingly flood dominant over time, with the Pussur River exhibiting greater flood dominance in tidal asymmetry compared to the Sibsa River. Incorporating morphological changes into the model could enhance results and provide a more accurate understanding of the sedimentation issues in the SP estuary.

Keywords: Harmonic analysis, Morphological changes, Sibsa-Pussur Estuary, Spatiotemporal evolution, Tidal asymmetry, Tidal constituent.

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A STUDY ON THE OPTIMIZATION OF DREDGING ALIGNMENT AND PERFORMANCE OF BANK PROTECTION WORKS ALONG TETULIA RIVER AT BAKERGANJ AND BAUPHAL UPAZILLAS

 

M. Shahabuddin^1*, A. K. M. Ashrafuzzaman¹, O. A. Maimun¹, B. Roy¹, M. A. H. Podder¹, M. Tofiquzzaman¹, M. K. Eusufzai² and P. Kanungoe¹

 

¹Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author (E-mail: mshahabuddin@rri.gov.bd)

²Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

 

Abstract

This paper presents the results for finalization of the proposed dredging alignment & its design and performance of the revetment for bank protection work in the Tetulia River at Bakerganj and Bauphal upazillas using scale modeling. The model is an overall distorted morphological model having horizontal scale 1:600 and vertical scale 1:80. The main purpose of this model is to provide decision support for determining of suitable and optimal dredging alignment and to investigate the efficacy of the proposed bank protection work to ensure a stable river course facilitating smooth navigation. The river reaches of about 50 km of Tetulia River and about 10 km of Karkhana River have been reproduced in this study. Different application test runs were conducted with different test scenarios (introducing revetment & dredged channel) using different discharges (ebb & flood) conditions. A 7 km revetment is proposed at the right bank of Tetulia River and 0.5 km at the left bank of Karkhana River. Model study shows it works well and is recommended. Dredged channel alignment is optimized along the left side channel of Char Durgapasha at a shallow depth. The longitudinal bed slope of the dredged channel is 4 cm km-1. The bottom width of the dredged channel is considered as 120 m. Total volume of material to be dredged under this test condition is around 10,26,685 m3. The recommended length of dredged channel is 2.534 km having bottom width 120 m, bottom level -9.0 mPWD, longitudinal bottom slope 4.0 cm km-1 and side slope 1:3. The volume of dredged material is 10,26,685 m3 for dredged channel section of recommended dredging option. About 56% of the dredged volume, or approximately 574,944 m3, was used to fill up the dredged channel. To maintain the channel's usability, maintenance dredging once a year for two years is recommended.

Keywords: Application, Bank Protection Work, Discharge, Dredging, Dumping, Maintenance, Offtake, Performance, Revetment, Scenarios.

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SLOPE STABILITY ANALYSIS OF THE LEFT BANK OF ARIAL KHAN RIVER OF BANGLADESH

 

U. Saha^1*, M. Moniruzzaman^1,2, N. C. Ghosh^3,4, B. Roy⁵, S. Ferdhous¹, M. E. A. Mondal⁶, M. K. Eusufzai³, K. R. Karim¹ and S. M. A. Horayra⁷

 

¹Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author (E-mail: umasaharri@gmail.com)

²Institute of Water and Flood Management, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

³Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

⁴Department of Physics, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

⁵Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

⁶Administration and Finance Directorate, River Research Institute, Faridpur-7800, Bangladesh.

⁷Office of the Director General, River Research Institute, Faridpur-7800, Bangladesh.

 

Abstract

Slope instability is one of the major problems in geotechnical engineering where loss of life and property are in hazardous situation. Therefore, it is essential to check the stability of slope. Such an important earthen structure is river bank slope. Here an attempt has been made to analyze the slope stability of the left bank of Arial Khan River at Khas Char Bachamara. Slope stability has been analyzed through geotechnical investigation with parameters cohesion, angle of internal friction, unit weight, slope angle and slope height etc. Geo05 software has been used for slope stability analysis. For slope stability analysis the two methods such as Bishop simplified and Janbu methods have been used for finding safety factor. Here safety factor of Bishop simplified has been considered as it gives low value of safety factor. Accordingly, from the slope stability analysis it has been observed that left bank of Arial Khan River at Khas Char Bachamara is stable at the coordinates (204966.442E & 2589225.303N) and (204765.552E & 2589425.425N) however, at the coordinate (204864.521E & 2589699.255N) the bank is not stable of the study area according to safety factor 1.50 of slip circle. Safety factor less than 1.50 recognize the river bank is unstable and a design engineer may reconstruct with reinforcement through injecting cement.

Keywords: Arial Khan River, Geotechnical Investigation, Left bank, Slope stability.

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IMPACT OF GEOTECHNICAL PROPERTIES ON BANK FAILURE MECHANISM AT DAULATDIA FERRY GHAT OF PADMA RIVER OF BANGLADESH

 

U. Saha^1*, N. C. Ghosh^2,3, M. Moniruzzaman^1,4, S. Ferdhous¹, F. Rukshana¹, M. D. Bawali¹, B. Roy⁵ and K. R. Karim¹

 

¹Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author (E-mail: umasaharri@gmail.com)

²Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

³Department of Physics, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

⁴Institute of Water and Flood Management, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

⁵Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

 

Abstract

The river bank of Bangladesh is generally established of alluvial deposit which contains sand, silt and clay particles. Char Bahirdia is one of the vulnerable bank sides of the Padma River adjacent to Daulatdia ferry ghat of Goalanda upazilla of Rajbari district. Bank failure mechanism depends on different hydraulic properties of the river and the geotechnical properties of the river bank. The study area is selected for investigation of the geotechnical properties and its impact on the bank failure of Daulatdia ferry ghat of Padma River. The study findings indicate that the cohesive soil strata are soft to hard which are less permeable and challenge surface erosion due to their permeability. This reduces the effects of seepage and piping. However, because of their permeability soil water pressure increases which are subjected to failure during rapid drawdown of water levels as well as soil erosion from toe zone. As a result, the river bank fails as toe failure due to tension crack. On the other hand, the non-cohesive soil strata are very loose to medium dense and dense and there is no bonding between the soil particles as clay particles are almost absent. Pore pressure increases with the increases of saturation and shear strength decreases with the increases of pore pressure. The results show the river bank tends toward the failure disposition. In addition, it is observed that the standard penetration resistance–N values have been changed along all the holes as bored where the soil layers are sometimes very loose and sometime medium dense to dense. As a result, rising of water level intensifies water pressure and increased velocity contributes to the bank failure over there due to liquefaction.

Keywords: Bank failure, Daulatdia ferry ghat, Geotechnical properties, Padma River.

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CORRELATION BETWEEN MAXIMUM DRY DENSITY AND SOIL PARTICLES’ SIZE USING MODIFIED PROCTOR TEST: A CASE STUDY

 

K. R. Ahmed^1*, F. Rukshana¹, M. M. R. Mondol^1,2, M. D. Bawali¹ and M. E. A Mondal³

 

¹Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author: (E-mail: krahmed147@gmail.com)

²Department of Civil Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

³Administration and Finance Directorate, River Research Institute, Faridpur-7800, Bangladesh.

 

Abstract

Soils are aggregates of mineral particles, along with air and water in the voids. Soil compaction is the most vital factor in any earthwork's construction. Compaction improves the engineering properties of the soil. Experience and experimentation have shown us that compacting the soils we use makes the infrastructure more sustainable, along with some other advantages. In this study, a particular amount of soil samples was collected in a large bag to find out the maximum dry density of the soil specimen, and several numbers of soil samples were collected from various point locations. The dry density of the soil samples was determined by calculating the moist density and moisture of the specific soil samples. Then, the performance of soil compaction work was determined by calculating the degree of compaction. There were four locations on the site in Kushtia. The average degree of compaction at each of the four locations was above ninety percent, which was in the acceptance range. From the regression graph of the maximum dry density and percentage of particle size, it is clear that the maximum dry density will increase with the increase of the clay and silt portion. With the expansion of the smaller particles, the value of maximum dry density will rise. There were a very small numbers of research work on correlating the dry density with the soil particle characteristics. In this work, the variation of the dry density of soil samples with the types and sizes of the particles is described vividly.

Keywords: Compaction test, Dry density, Modified Proctor test, Moisture, Soil particles, Strength.

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DESIGN SCOUR DEPTH AROUND THE PIER OF THE RAILWAY BRIDGE ACROSS THE JAMUNA RIVER IN BANGLADESH: A PHYSICAL MODEL BASED APPROACH

 

A. K. M. Ashrafuzzaman^1*, M. J. Islam¹, M. Shahabuddin¹, S. K. Ghosh¹, M. Tofiquzzaman¹, M. K. Eusufzai², M. Moniruzzaman^3,4 and M. E. A. Mondal⁵

 

¹Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author: (E-mail: ashrafcebuet89@gmail.com)

²Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

³Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

⁴Institute of Water and Flood Management, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

⁵Administration and Finance Directorate, River Research Institute, Faridpur-7800, Bangladesh.

 

Abstract

For further enhancement of the capacity and to overcome the loading restriction of existing Bangabandhu Sheikh Mujib Multipurpose Bridge, it would be essential to construct a parallel railway bridge, dedicated to railway, while the existing bridge could carry road traffic only. In this context, Bangladesh Railway has decided to construct the proposed Bangabandhu Sheikh Mujib Railway Bridge over the Jamuna River which will be located 300 m upstream of the existing bridge. Therefore, a study was undertaken by River Research Institute (RRI) to support the design required for the proposed railway bridge using scale modelling having scale 1:100. The study shows that maximum scour occurred around the bridge piers is 27.5 m (-21.0 mPWD) at pier-3 (of existing Bangabandhu Sheikh Mujib Multipurpose Bridge) & 39.4 m (-31.9 mPWD) at pier -3 (of proposed Bangabandhu Sheikh Mujib Railway Bridge) when a barrier is provided to impinge the flow on the revetment and bridge piers. The study also shows that maximum velocity around the bridge piers is 3.68 ms-1 & 4.52 ms-1 at existing bridge pier-2 & proposed bridge pier-2 respectively under 60-degree oblique flow attack at the bridge corridor guide bund. In addition, maximum scour around the revetment of west guide bund (WGB) is 29.5 m (-23.5mPWD) when the approach flow condition has been changed by providing a barrier to concentrate the flow around the upstream tip of revetment. Moreover, maximum velocity found around the revetment of WGB is 5.3 ms-1 (at the upstream tip of WGB) when the launching portion of revetment is strengthened as per design under 200-yr water level (WL) 14.49 mPWD and discharge (Q) 111,000 m3s-1.

Keywords: Bangabandhu bridge, calibration, guide bunds, Jamuna River, River Training Work (RTW), Scour depth, Undistorted model and West Guide Bund (WGB).

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A STUDY ON OPTIMIZATION OF RIVER TRAINING AND BANK PROTECTION WORK FOR PAIRA BRIDGE PROTECTION

 

A. K. M. Ashrafuzzaman^1*, M. J. Islam¹, M. Shahabuddin¹, S. K. Ghosh¹, M. Tofiquzzaman¹, M. K. Eusufzai², M. Moniruzzaman^3,4 and M. E. A. Mondal⁵

 

¹Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author: (E-mail: ashrafcebuet89@gmail.com)

²Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

³Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

⁴Institute of Water and Flood Management, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

⁵Administration and Finance Directorate, River Research Institute, Faridpur-7800, Bangladesh.

 

Abstract

A study was undertaken to optimize the river training and bank protection work for the safeguard of the bridge on the Paira River on Barisal-Patuakhali Road using scale modelling. About 3.0 km river reach including the bridge was reproduced in this study. The study shows that the length of the revetment required along the Paira river bank is 921 m & 554 m respectively at the upstream & downstream of the Varani khal mouth. The curved length of the upstream & downstream termination of revetment in the Paira river at the crest (top) of embankment is 41.9 m, at the inner side (end of slope pitching) 60.2 m and at the outer side (end of launching apron) 206.8 m. The research also reveals that maximum local scour near the revetment is 19 m (-52.5 mPWD), Pier No.18 experiences maximum local scour around it which is 8m (-30.5 mPWD). It is found that maximum velocity around the revetment and bridge piers is 3.04 ms-1 and 2.88 ms-1 respectively. Maximum velocity of 2.2 ms-1 is found around the pier no. P18 and maximum velocity is 3.1 ms-1 at the downstream termination of revetment with 100-year return period discharge. The maximum velocity along the left bank at upstream of bank revetment is found 2.62 ms-1and at downstream of it is 3.04 ms-1. Severe flow concentration at the left bank of Paira River adjacent to the Varani khal and Paira bridge is observed with present planform and ebb flow condition.

Keywords: Bridge, Bank protection, Optimization, Pier, Revetment, River training, Scour, Velocity.

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IRON REMOVAL PERFORMANCE OF MULTI STAGE FILTRATION UNITS FROM GROUND WATER OF BANGLADESH

 

M. M. R. Mondol^1,2*

 

¹Geotechnical Research Directorate, River Research Institute (RRI), Faridpur-7800, Bangladesh.

²Department of Civil Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

^*Corresponding Author (E-mail: mrmondol68@gmail.com)

 

Abstract

Iron is found widely distributed in both surface and ground waters in nearly all geographic areas. Dissolution of iron occurs by various processes and results in a variety of conditions regarding the concentration and chemical forms in which they are found in water. Iron in concentrations greater than 0.3 ppm stains plumbing fixtures and laundered clothes. Although discoloration from precipitates is the most serious problem associated with water supplies having excessive iron, foul tastes and odors can be produced by the growth of iron bacteria in water distribution mains. The iron problem has long been recognized in Bangladesh and many technologies have been developed for iron removal at municipal, community and household levels adopting the techniques of oxidation, sedimentation, precipitation and filtration process. To conduct this study six individual filtration units treating tube well water having iron concentrations ranging from 4.6 to 16 ppm installed at Sirajgonj, Cumilla and Jashore districts of Bangladesh have been selected. Crushed brick chips have been used as adsorptive media for the filtration units. Collected raw water samples and treated water samples from different chamber of the filtration units were tested in the laboratory for determining the concentration of residual iron and other relevant water quality parameters. The result reveals that higher the initial tube well water iron concentration, greater is the iron removal performance. Depending on raw water iron concentrations around 89.13 to 98.25 % iron removal performance have been achieved.

Keywords: Concentration, DRF, Effluent, Iron, MSFU, Removal Performance, URF.

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A STUDY ON THE IMPROVEMENT OF WATER RETENTION CAPACITY OF THE LOWER KARATOA RIVER UNDER BOGURA DISTRICT THROUGH DREDGING AND SETTING UP OF A PROPOSED REGULATOR

 

M. J. Islam^1*, A. K. M. Ashrafuzzaman¹, M. E. A. Mondal², S. M. A. Horayra³, S. K. Ghosh¹, K. R. Ahmed⁴, M. K. Eusufzai⁵ and P. Kanungoe¹

 

¹Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author: (E-mail: johurul1999@yahoo.com)

²Administration and Finance Directorate, River Research Institute, Faridpur-7800, Bangladesh.

³Office of the Director General, River Research Institute, Faridpur-7800, Bangladesh.

⁴Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

⁵Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

 

Abstract

The Lower Karatoa River originates from the Jamuneshwari-Karatoa (Upper Karatoa) River at Gobindogonj upazila under Gaibandha district and flows towards the west. From Gobindogonj upazila, the Lower Karatoa flows through Bagura district and finally falls into Bangali River under Sherpur upazila. At present, the Lower Karatoa River is fully silted up and dried up due to lack of water flowing through it. Therefore, a study is undertaken by River Research Institute (RRI) to support the design of proposed dredging and new regulator in the Lower Karatoa River using scale modelling. There is an existing regulator at its offtake whose sill level is around 3.0 meter above the water level of Upper Karatoa during dry season. A new regulator is proposed in addition to the existing regulator whose sill level is below the sill level of existing regulator to pass more flow in the Lower Karatoa River. The model is an undistorted model having horizontal and vertical scale 1:50. The study reach covers around 3.0 km of Upper Karatoa River and 1.5 km of Lower Karatoa River. The study reveals that one 4-vent regulator (each vent width 3.0 m) having sill level 14.50 mPWD is recommended to construct in the field just downstream of existing regulator. The recommended dredged channel has bottom width 15 m, side slope 1:2 and longitudinal slope 5.5 cmkm-1. Maintenance dredging for two successive years as suggested is recommended.

Keywords: Karatoa River, Maintenance dredging, Regulator, Scale model, Sill level, Silted up, Undistorted.

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A CASE STUDY OF MANAGING THE BRAHMAPUTRA-JAMUNA RIVER: A PHYSICAL MODEL BASED APPROACH

 

A. K. M. Ashrafuzzaman^1*, M. Shahabuddin¹, O. A. Maimun¹, S. M. A. Horayra², B. Roy¹, K. R. Ahmed³, S. Ferdhous³ and P. Kanungoe¹

 

¹Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author: (E-mail: ashrafcebuet89@gmail.com)

²Office of the Director General, River Research Institute, Faridpur-7800, Bangladesh.

³Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

 

Abstract

Rowmari and Rajibpur are two upazilas under Kurigram district located near the left bank of the Brahmaputra-Jamuna River. These upazilas are suffering from severe flood of this river every year. Therefore, a study was undertaken by River Research Institute (RRI) to manage the Brahmaputra-Jamuna River in terms of bank protection works and dredging using physical modelling. The study provides support to the design of protective work and dredging required for the erosion prone areas. A stretch of about 26 km of the Brahmaputra-Jamuna River and part width of around 6 km have been reproduced in the model study. The model is distorted having horizontal scale 1:600 and vertical scale 1:80. The study was conducted with 2.33 and 100 year return period using three different options for the protection of erosion prone areas. In Option-1, a total of 11.59 km protective work is required to protect the erosion prone areas. In this case, maximum velocity and scour around the proposed protective work are found as 1.75 ms-1 and 6.88 m (18.32 mPWD) respectively. In Option-2, the proposed dredging through the Brahmaputra-Jamuna River would ensure the stability of the bank protection work by reducing the flow attack near the left bank and thereby, reducing the near bank flow velocity. But the dredged channel is found to be mostly silted up. The model results indicate that the average percentage of filling up of the dredged channel is about 46.72% in one year. For Dighla Para Char stabilization (Option-3), the length of the proposed bank protective work surrounding the char is 21.654 km which may not be economically feasible as it involves huge cost and environmental & other issues. But under this option a huge area of land (around 33 sq.km) will be reclaimed due to char stabilization.

Keywords: Bank protective work, Brahmaputra-Jamuna River, Discharge, Dredging, Reclamation, Scour, Stabilization, and Velocity.

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ASSESSMENT OF THE PHYSICOCHEMICAL PARAMETERS AND THE WATER QUALITY INDEX AT THE UPSTREAM PART OF THE SANGU AND MATAMUHURI RIVERS OF BANGLADESH

 

N. C. Ghosh^1,2,3*, K. B. Anwar³

 

¹Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

²Department of Physics, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

³Isabela Foundation, Dhaka-1209, Bangladesh.

^*Corresponding Author: (E-mail: nayan.ghs@gmail.com)

 

Abstract

This study assessed 16 water quality parameters in situ at 4 locations in the upstream valley of each Sangu and Matamuhuri Rivers. Water Temperature (WT), pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), and Dissolved Oxygen (DO) were measured by direct probe method. Total Alkalinity (TA), Chloride (Cl-), Total Hardness (TH), and Carbon-di-oxide (CO2) were measured by titration method, and Turbidity, Total Suspended Solids (TSS), Ammonia (NH3), Nitrite (NO-2), Nitrate (NO-3), Sulfate (SO2-4), and Orthophosphate (PO3-4) were measured by colorimetric method. The Canadian Council of Ministers of the Environment Water Quality Index (CCMEWQI) was used to calculate the water quality index (WQI). Water quality parameters pH, EC, TDS, DO, TA, Cl-, TH, CO2, NO-2, NH3, NO-3, and SO2-4 were found within the range of standard values for drinking water in all the points of both the rivers, whereas, the WT was found slightly low (19.9°C) from the standard values (20-30°C) at one point of the Matamuhuri River. CO2 and PO3-4 were higher than the standard values at all sampling points of both rivers, with a mean value of 26.15 mgL-1 having a standard deviation (SD) of 1.61 and 0.19 mgL-1 (SD 0.05) for Sangu River and 24.15 mgL-1 (SD 4.49) and 0.21 mgL-1 (SD 0.03) for Matamuhuri River respectively. The turbidity was higher at all the points of the Sangu River, whereas at two points of the Matamuhuri River. TSS was higher at two and one points of the Sangu and Matamuhuri Rivers, respectively. The CCMEWQI of the Sangu and Matamuhuri Rivers was calculated at 82.95 and 81.08, respectively. The water quality, according to the CCMEWQI for both the Sangu and Matamuhuri Rivers, was in the “good” category of the index.   

Keywords: Sangu, Matamuhuri, Physicochemical, Water Quality Index, WQI, CCMEWQI.

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HUMAN HEALTH RISK ASSESSMENT FROM THE CONTAMINANTS OF MAHANANDA RIVER WATER AND ITS ADJACENT GROUNDWATER IN BANGLADESH

 

N. C. Ghosh^1,2*, M. Moniruzzaman^3,4, M. M. R. Mondol^3,5

 

¹Dhaka Laboratory, River Research Institute, Dhaka-1205, Bangladesh.

²Department of Physics, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

^*Corresponding Author: (E-mail: nayan.ghs@gmail.com)

³Geotechnical Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

⁴Institute of Water and Flood Management, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

⁵Department of Civil Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.

 

Abstract

This study aims to assess the physicochemical parameters of the surface water of the Mahananda River and the concentration of the nutrients of the Mahananda River water and the adjacent groundwater. Among physicochemical parameters, pH, Dissolved Oxygen (DO), and Total Dissolved Solids (TDS) were measured on 18 sampling sites of the river, while Sulfate (SO42-), Orthophosphate (PO43-), Arsenic (As), and Manganese (Mn) concentrations were measured on 17 equidistant sampling sites of the river and the adjacent groundwater. The mean pH value was 8.50 with a standard deviation (SD) of 0.30. DO and TDS were 9.56 mgL-1 (SD 1.67) and 127.62 mgL-1 (SD 24.76), respectively. The mean SO42- concentration was found to be 5.38 mgL-1 (SD 12.00) for groundwater and 2.29 mgL-1 (SD 1.96) for surface water, while the mean PO43- concentration was 1.17 mgL-1 (SD 0.78) and 0.63 mgL-1 (SD 0.15) for groundwater and surface water respectively. The contamination of As was found to be as high as 100 µgL-1 in the groundwater while within 25 µgL-1 in the surface water. Mn concentration was high at almost all the points, with a mean value of 1.64 mgL-1 (SD 0.90) and 0.54 mgL-1 (SD 0.23) for the groundwater and surface water, respectively. The carcinogenic risk from As and non-carcinogenic risk from both As and Mn was estimated for adults and children. The carcinogenic risks were found to be high for both surface water and groundwater, while non-carcinogenic risks were found high for surface water and very high for groundwater. In both cases, children were found more vulnerable than adults.

Keywords: Arsenic, Carcinogenic Risk, Groundwater, Mahananda River, Manganese, Non-Carcinogenic Risk.

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ASSESSMENT OF EROSION-ACCRETION AND IDENTIFICATION OF THE CHANGE IN BANK LINE OF THE PADMA RIVER IN BANGLADESH USING GIS AND RS APPROACH

 

M. E. A. Monda^l*, A. A. Imran², M. Shahabuddin² and B. Roy²

 

¹Administration and Finance Directorate, River Research Institute, Faridpur-7800, Bangladesh.

^*Corresponding Author: (E-Mail: emranhossainduet@gmail.com)

²Hydraulic Research Directorate, River Research Institute, Faridpur-7800, Bangladesh.

 

Abstract

The Ganges-Padma is an important river system in South Asia which supports the life and livelihoods of millions of people both in India and Bangladesh. Bangladesh is a riverine country. Every year the country faces many natural hazards due to the natural dynamic behavior of these rivers. These dynamic actions motivate massive migration of banks, producing thousands of homeless families and enormous land losses each year. This study has analyzed the severity of erosion, accretion and bank shifting of the Padma River at Bagha-Rajshahi, Lalpur-Natore, Ishwardi-Pabna and Bheramara, Daulatpur-Kushtia district. Remote Sensing (RS) and Geographic Information Systems (GIS) techniques were applied to calculate erosion, accretion and bank shifting. This study has been carried out to evaluate the river shifting and assessment of related effects on the land-use/land cover using geographic information system (GIS) and remote sensing (RS) techniques between 1972 and 2023 for Padma River in Bangladesh. Only secondary data has been applied for obtaining the research goal. Several computer software such as ArcGIS, Google Earth etc. have been applied to examine raw data. Seven USGS Landsat, MSS, ETM, OLI_TRIS, sensor, and data images between 1972 and 2023 were used in this study. Padma's riverbank shifting designs and changing land cover resulting from 51 years of erosion and accretion methods have been practical. These river shifting rates are based on the difference between 1972 to 1980, 1980 to 1990, 1990 to 2000, 2000 to 2010, 2010 to 2020 and 2020 to 2023. The average rates of erosion and accretion are 506.41 hectares/year and 468.70 hectares/year individually. This study shows that the river bank line shifted significantly between 1972 and 2023 and this triggered massive bank erosion and accretion.

Keywords: Accretion, ArcGIS, Bank Shifting, Erosion, Khulna, Rajshahi, River Dynamics.

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