Dissertations/Theses - Department of Water Resources Engineering

Browse

Filters

1990 - 199977

Settings

Start date: 1990End date: 1999

Search Results

Now showing 1 - 10 of 77
  • Thumbnail Image
    Item
    Optimal method for prediction of channel geometry in alluvium
    (Department of Water Resources Engineering, 1992-08) Ziaul Haider; Abdul Matin, Dr. Md.
    For abstract please see full text
  • Thumbnail Image
    Item
    Study of aggradation and degradation of the Khowai river
    (Department of Water Resources Engineering, 1997-08) Tarek Bin Hossain; Hossain, Dr. M. Monowar
    The study was conducted to investigate the aggradation and degradation of the Khowai River bed. Assessment of future sedimentation along the Khowai river was also carried out. The reach extends from Ballah to the confluence of Khowai- Dhaleswari River and has an overall length of 87 km. To carry out the investigations 39 sections of the Khowai River form Ballah to the Khowai-Dhaleswari confluence for the year 1988, 17 cross sections form Shaistaganj to Khowai-Dhaleswari confluence for the year 1994 and a thalweg profile for the year 1965 were collected in the digitized form from FAP-6. Data on suspended sediment concentrations at the Shaistaganj station between years 1964 and 1993 were also collected from River Research Institute (RRI), Faridpur. Mean daily water levels for the gauge stations at Ballah, Chunarughat, Shaistaganj and Habiganj form 1964 to 1994 and mean daily discharges at Shaistaganj station for the same years were collected from Surface Water Modelling Centre (SWMC). Bed material gradation curves for the year 1992 at Chunarughat gauge, Shaistaganj gauge, Habiganj gauge and downstream of Habiganj gauge were collected from FAP-6. Suspended sediment particle size distribution curves for the years 1991 and 1992 at Shaistaganj were collected from SWMC. Cross-sectional properties at 17 locations between Shaistaganj and the Khowai-Dhaleswari confluence between years 1988 and 1994 were analyzed and it was observed that the river between the reach is becoming narrower and the average thalweg level has degraded by 1.29 m between Shaistaganj and 6.6 km downstream of Habiganj. The total reach of this degraded thalweg is about 21 km in length. After that up to the confluence of Khowai and Dhaleswari River the average thalweg level has again suffered degradation by 2.03 m on an average during the study period. The cross sectional area at bankfull stage is being increased at the rate of 10.1 m2 per year since 1988. It was also observed that in most of the occasions the cross sectional area above bankfull stage has reduced indicating deposition of sediment on the berms and flood plain on both sides of the river. The overall cross section of the 23.44 km reach below Shaistaganj is being reduced at the rate of 14.84 m2 per year since 1988. It was also observed from the analysis of the water level records between years 1964 and 1994 that Khowai river bed level is being aggraded at the gauge stations at Ballah, Chunarughat, Shaistaganj and Habiganj by 0.96 m, 0.2 m, over 1 m, and 1.5 m respectively since 1964. Study of the thalweg profiles between years 1965 and 1988 suggested that the Khowai River has aggraded by 1 m between Ballah and Chaunarughat and degraded by 1 m between Chunarughat and Shaistaganj. Mean bed level profiles of 1988 and 1994 suggested average aggradation by 0.4 m between Shaistaganj and 6.6 km downstream of Habiganj. After that up to the end of the river i.e. the confluence of Khowai and Dhaleswari River it suffered degradation by 0.5 m. The mean bed level profile of 1994 showed a scour hole due to the loop cut made by BWDB in the year 1992 at 9 km downstream of Habiganj. Analysis of bed material curves and suspended sediment particle size distribution curves based on Einstein's theory suggested that the inflowing sediment load at Shaistaganj stations consisted of 30% coarser fraction of the suspended load and 70% wash load. Future prediction on the Khowai River sedimentation was made using HEC-6 based on channel geometry of 1988. The study revealed that there would be continued deposition of sediment indicating continued aggradation of the bed level along the study reach of the river.
  • Thumbnail Image
    Item
    Evaluation of selected local scour formulae around piers and groynes
    (Department of Water Resources Engineering, 1998-12) Anwaruzzaman, Syed Md.; Hossain, Dr. M. Monowar
    For abstract please see full text
  • Thumbnail Image
    Item
    Performance evaluation of early inplemantation project : a case study
    (Department of Water Resources Engineering, 1993-06) Ismail Ali, Syed; Bari, Dr. M Fazlul
    For abstract please see full text
  • Thumbnail Image
    Item
    Assessment of environmental impacts of water development projects using overlay technique
    (Department of Water Resources Engineering, 1998-06) Iqbal Khosru, Syed; Nishat, Dr. Ainun
    Environmental Impact Assessment (EIA) has been made mandatory for all water development projects in Bangladesh, to be carried out at project planning stage. The main objective of EIA is to identify the probable effects, both beneficial and adverse, resulting from the project. Then through EIA, suggestions are given to the planners so as to minimize and mitigate the negative or adverse impacts and enhance the positive or beneficial impacts. EIA then prepares an Environmental Management Plan (EMP) for future monitoring of the project, both during and after its implementation so that sustainability is ensured. There are a number of techniques for carrying out EIA namely: Checklist, Matrices, Networks, Environmental Evaluation System, Overlay Technique, Environmental Impact Indices and Costbenefit Analysis. Besides, many institutions have developed their own guidelines for EIA. Bangladesh has adopted the Weighted Matrix method and a guidelines for carrying out EIA of water development projects has already been developed and adopted. Every method has some advantages and disadvantages in their application. As for example, Network method has been found suitable for identifying secondary and as well as tertiary impacts. Overlay technique is considered suitable for presentation of spatial variation in impacts. This study was taken up to carryout a comparative study of the various methods of EIA and evaluate whether some elements of Overlay technique can be adopted while presenting findings through Weighted Matrix method in accordance with the approved guidelines. To carry out these objectives, data available from post evaluation of the System Rehabilitation Project (SRP) were used. SRP, during 1990-95, rehabilitated 35 water development projects of the Bangladesh Water Development Board (BWDB). A multidisciplinary Evaluation Team assessed seven SRP projects, using EIA methodology. In this study, data of two projects were used. GIS based mapping technique was used to produce the Overlays. For comparison with conventional method, some important environmental components (lECs) were chosen, namely: Flood Control, Drainage, Irrigation, Crop Damage and Capture Fisheries. Other IECs, relevant to water resources development and management projects have been identified on the basis of various studies available on evaluation of completed projects. Preliminary assessment of suitability of overlay techniques and availability of data led to selection of the aforesaid five parameters. For this type of projects, modification in flooding characteristics and changes in cropping are most significant parameters. It has been found that EIA results can be better presented through Overlays for the selected IECs. Impact of probable floods, corresponding to various return periods, and matching with any river water level, on the project area, can be clearly represented by Overlay. Similarly improvement in drainage in post-monsoon condition can be better represented with spatial variations shown on the maps. Impact of the project on potentials as well as actual performance of irrigation were clearly visible in Overlay maps. Impacts on capture fisheries, studied with overlays, clearly demarked the areas of potential conflict between agriculture and fisheries. It was observed that in the projects studied, such conflict was prevalent over small areas. On the other hand flooding pattern has significantly adverse impact on agriculture. These analysis would be of great value in future water management practices. Finally it can be said that, overlay mapping can have very important role in the EIA process. The conventional method can not assess the impact and quantify the spatial variation. The method is also very flexible and the importance of the time function can be well addressed.
  • Thumbnail Image
    Item
    Study on hydraulic geometry of the ganges
    (Department of Water Resources Engineering, 1992-05) Das, Swapan Kumar; Hossain, Dr. M. Monowar
    For abstract please see full text
  • Thumbnail Image
    Item
    Comparative study of drainage coefficient of Teesta barrage project
    (Department of Water Resources Engineering, 1993-11) Roy, Subash Chandra; Miah, Dr. M. Mirjahan
    For abstract please see full text
  • Thumbnail Image
    Item
    Stochastic analysis of deficiency of crop water requirement under rainfed condition in Bogra and Rangpur areas
    (Department of Water Resources Engineering, 1999-02) Bhattacharyya, Shyamal Kumar; Bhuiyan, Dr. Muhammed Ali
    For abstract please see full text
  • Thumbnail Image
    Item
    Determination of metrological drought index for north-west Bangladesh
    (Department of Water Resources Engineering, 1997-09) Datta, Kumar Datta; Bhuiyan, Dr. Muhammed Ali
    For abstract please see full text
  • Thumbnail Image
    Item
    Simulation of subsurface water flow by galerkin finite element method in the Dhaka city aquifer
    (Department of Water Resources Engineering, 1998-08) Shikha Rahman; Bhuiyan, Dr. Muhammed Ali
    A two-dimensional mathematical model has been developed USll1gGalerkin finite element method for simulation of transient saturated-unsaturated groundwater flow in multiaquifer system with window based, menu-driven, user friendly interface to provide on screen input data interpretation, to guide user through steps of data processing, and to generate reports and graphs from output results. The model is able to handle combined and system-dependent boundary conditions that can be used in practical situation of groundwater flow in the complex hydrogeological conditions of a country like Bangladesh in general and particularly for Dhaka City. Due to less complexity in 2-D simulation and the availability of GUI the model is easier to use and time efficient. The p.(ogram deals with a variety of boundary conditions encountered in real hydrogeological situation consisting of simple constant or time dependent prescribed head (surface water bodies) or prescribed flux boundaries (pumping well, recharging well etc.), complicated system-dependent and atmosphere-controlled boundary including the near-surface activities i.e., precipitation, evaporation, root water extraction and surface ponding caused by excess precipitation and also boundary along the riverside having variable seepage face conditions. With a view to make the model more user friendly and efficient in operation a Graphical User Interface (GUI) is designed to handle the user input, reporting the output and graph generation. This GUI is designed and implemented using Object Oriented Programming language Visual Basic that will make the Fortran program operable in the 32-bit faster windows environment. To test the different features incorporated in the model, a number of published schematized problems have been simulated by the program. Five such problems are presented in detail in this thesis with simulated results. The program and the modification made were tested on the following examples: I. One-dimensional vertical soil column with the variable atmospheric boundary condition and with water extraction by plant roots, 2. One-dimensional vertical soil column without the variable atmospheric boundary condition 3. two-dimensional rectangular vertical flow domain with the variable seepage-face boundary condition, without influence of atmosphere. 4. Two-dimensional vertical flow domain representing a simplified nver bank situation with both variable atmospheric and variable seepage-face boundary conditions (Coarser Grid) 5. Two-dimensional vertical flow domain representing a simplified nver bank situation with both variable atmospheric and variable seepage-face boundary conditions (Finer Grid) The effect of grid fineness is tested in examples 4 and 5. To verify the model responses in simulating a complex real hydrogeological situation Dhaka City aquifer is studied. The boundary conditions of the domain are derived from the river water level and piezometric level data. Model calibration of the parameters has been performed under this study. Simulated water balance components identify the river effect as the most dominating recharge mechanism of the area, which contributes around 60 percent of the total volume of abstraction. Urban recharge (taken 30% of the total abstraction) also contributes to the abstraction volume of the area. The results of simulation show that the approach is fruitful and can be used for detailed study of the groundwater status of the Dhaka City aquifer in future. The program is proved to work well but have a disadvantage of being associated with the time step of the atmospheric input data, which is usually I day. Shorter and/or automatically set time step for the atmospheric input data, as well as for the boundarycondition subroutines, is therefore recommended. A need has been also identified for yet more flexible treatment of combined and system-dependent boundary conditions (e.g. a combination of the variable atmospheric boundary condition with the variable seepage-face one) and for the coupling of the present model with a two-dimensional model of surface runoff in a flood plain.