Dissertations/Theses - Department of Water Resources Engineering

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Start date: 1981Subject: search.filters.subject.Water resource management-Bangladesh

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    Impact of climate change on rural livelihood: a case study
    (Department of Water Resources Engineering, 2010-05) Anowar Saadat, Muhammad; Saiful Islam, Dr. A.K.M.
    This study has been conducted to figure out the changes in salient climatic parameters and there impacts on rural livelihood as well as to develop a sustainable livelihood framework. Two villages, namely Chander chak and Mauli at Kalia Upazilla under the coastal district Narail were chosen as the study area. Three livelihood groups; farmer, fisherman, wage laborer and also the woman as vulnerable group were selected for the study. The local climate change condition has been illustrated with observed data and the probabale future scenario has been extracted from Regional Climate Model (RCM) prediction. This prediction was conveyed to the local people to express their observation according to their perception. People's information has been incorporated to the development of the livelihood framework which will provide them a sustainable livelihood against the climate change context. In the study area, 73% of the rural people are farmers, 22% are farm laborers and 5% are fishermen whereas the woman are 50% of the total rural population. From the RCM prediction, it has been found that the temperature of the study area will rise 3-4°c and the monsoon rainfall will decrease by 12-15% of the annual rainfall whereas the total annual rainfall will increase by 17%. Following these circumstances, the probable impact on the rural livelihood was worked out. According to the findings, the farmers overall access to natural capital is 75% which will come down to 54% in climate change context. The 76% access to the physical capital will be reduced to 63% due to damages caused by frequent disasters. Due to less productive land and insecure public property, the financial capital will be affected by 30% of the present condition. The farm laborers will be similarly affected as the farmers as they mostly are engaged in farm activities. Annual work days will be 40% less and their financial capital will reduce from 58% to 44%. The fishermen's fishing activity will reduce to 25% in a year and the fish diversity in the waterbody will be affected as 40% of fish will be lost from their habitats in future. As the fishermen are less in number in the village, their access to social capital will reduce from 65% to 45%. The woman have low access to natural capital which will go down by 30% due to climate change. Their income generating activities will be reduced and financial capital will come down from 50% to 40%. For all the livelihood groups, the increasing hot and dry weather will increase illness by 15% causing more diarrhea, cholera and vector bond diseases. Adaptive measures like effective use of agricultural lands and waterbodies, infrastructure rehabilitation, better health care, natural resource conservation, afforstation, etc. are necessary to protect the livelihood capitals and provide the people a sustainable livelihood in the coming days.
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    Performance evaluation of the participatory water management of some selected small- Scale water resources projects of LGED
    (Department of Water Resources Engineering, 2008-03) Mizanur Rahman, Md.; Bhuiyan, Dr. Muhammed Ali
    During the period from April 1996 to December 2002, LGED implemented the Phase- I of the Small-Scale Water Resources Development Sector Project (SSWRDSP-I). The purpose was to rehabilitate and/or upgrade 280 small-scale water control systems, called sub-projects, in western part of Bangladesh with much emphasis on people's participation. The sub-projects comprised of flood control, drainage improvement, water conservation and command area development schemes. The Project was implemented with the aims of agricultural development, floodplain fisheries, environmental mitigation measures, stakeholder and beneficiaries' participation, poverty reduction and gender development as core elements. Based on its achievement, the second phase SSWRDSP-II has been undertaken for implementation in the period from November 2001 through 2009. The performance of existing FCD projects can be significantly improved by developing a participatory approach. This study deals with the evaluating performance of such participatory water management system. The SSWRDSP has developed an approach to ensure sustainable O&M by establishing Water Management Cooperative Associations (WMCA). WMCA was supposed to assume O&M responsibilities of all the successfully implemented sub-projects of the LGED. In addition they facilitated community development activities via micro-credit among the stakeholders and beneficiaries. The study was conducted on three selected sub-projects of SSWRDSP of LGED. Of the selected sub-projects, two are from Phase-I and one from Phase-II. Out of those two sub-projects from Phase-I, one was selected on the basis of performance rated above average (Brazamul-Bhitikhal Sub-project) and the other one was selected as performance rated below average (Fuleswari Sub-project). These performances are reported by LGED officials and previous field investigations of different researchers. The third one was selected as a new sub-project from Phase-II (Alarnkhali Subproject). The study was carried out with mainly three objectives: i) to analyze the preand post-project conditions of the selected sub-projects, ii) to determine the factors affecting the performance and (iii) to assess the performance of the WMCAs. Relevant literatures were studied and questionnaire survey through field investigation was conducted for this purpose. In course of investigating the performance of the management system, socio-institutional, financial and environmental aspects have been considered for evaluation. All three selected WMCAs were found registered duly under cooperative laws. The WMCA formation processes, meeting attendance, conflict resolution, etc Brazamul- Bhitikhal sub-project and Alamkhali sub-project were found to be appropriate. Crop production and cropping intensity have increased remarkably in those two subprojects. But those increases were nominal in Fuleswari sub-project. Due to lack of beneficiaries' participation and O&M of the infrastructure by WMCA, Fuleswari subproject was not functioning well. There was no appreciable environmental change related to water quality and natural vegetation for pre- to post-project conditions. Natural fish migration hampered due to construction of embankment and regulators. But culture fish production has increased after implementation of the sub-project and better training. In Fuleswari sub-project, navigation has been obstructed due to inadequate implementation of facility for boat-passage across the embankment. There ware four public-cuts found at that embankment. The financial viability as per beneficiaries' contribution collection for cooperatives in all the three sub-projects is good (above 100%) but as per O&M fund collection Fuleswari sub-project shows very poor performance. Lack of beneficiaries' participation and lack of proper infrastructure maintenance by WMCA ware found to be the main reasons behind lesser success of those water schemes. The performance can be improved by increasing beneficiaries' involvement in local levels. Executive members of WMCA should be formed with dedicated stakeholders of the sub-projects and their activities should be monitored regularly. Linkage with WMCA and LGED project level authority must be further improved.
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    Effect of upstream withdrawal on river wetland connectivity in Surma-Kushiyara basin
    (Department of Water Resources Engineering, 2007-03) Abul Basar Mohammad Baki; Bari, Dr. M. Fazlul
    This research was undertaken to investigate the probable impact of upstream storage and diversion works on Barak river by India on a selected wetland area in the Surma and Kushiyara basin. Three scenarios of flow regulation chosen for analysis include: (i) average year flow without Tipaimukh dam, (ii) average year flow with Tipaimukh dam, and (iii) average year flow with Tipaimukh dam and Fulertal barrage. The Chunia beel wetland area and the Kakura kIwi, providing one major connectivity with the Surma river were chosen for detailed analysis. Through field visits on-site knowledge about the existing connectivity between the river system and wetland has been gathered. Also information about agriculture and fisheries were obtained. One-dimensional model simulation was performed for the average hydrologic year with the above three scenarios. The effect of upstream dam and barrage on annual peak flows and seasonal hydro graphs was analyzed. Two-dimensional model simulation was used to determine the changes in the extent and depth of flooding in the river basin. Changes in land type, that is how the inundation area of larger depths changes to a shallowcr depths and the consequent effect on cropping pattern and fisheries were studied for the selected bee I wet land area Due to the Tipaimukh Dam the peak flow in Surma river is likely to decrease by about 15% with about 3% decrease in the peak water level. The corresponding decrease .in the peak flow and water level in Kakura khal connecting the Surma and Chaunia beel will be about 32% and 3%, respectively. This causes reduction in the ,extent of flooding in the river basin as discussed below. In the pre-monsoon season, for Kakura khal water level shows an increase of 0.73 m in the first week of April causing a reversal of flow from the river to the khal. Similar reversal of now is observed in the second and fourth week of May. This may be due to pre-monsoon release from the reservoir to make room for flood storage. In the post-monsoon discharge decreases in a fluctuating manner in the first two weeks of October, then increases in the third week of the month, and thereafter a slight increase in discharge is observed for the rest of the period. In the dry season discharge increases slightly probably due to release for hydropower generation showing an increase in water level ranging from 0.7 m to 0.69 m. As to the extent of flooding in the river basin, it is seen that in the post-dam situation, the extent of inundation shows a decrease by about 60% in pre-monsoon, 22.5% in IV monsoon and 63% in post-monsoon season. For the barrage in addition to the dam no further change in inundation extent was evident from the simulation results. Also there will be some redistribution of Fa, F I, etc. land types. In the pre-monsoon season area of Fa land type shows an increase of about 18% whereas F I, F2, F3 areas decrease by 46, 76, 93% respectively and F4 type disappears. This means that the deeply flooded area decreases. Some additional changes in land types due to the effect of barrage in addition to the dam were seen to occur. Fa and FI land areas show a slight increase, F2 shows a slight decrease, and F3 and F4 types do not, change. In monsoon Fa and F2 land areas increase by about 11a and 39%, respectively, but F2, F3 and F4 areas decrease by 29, 49, and 97%, respectively due to dam. On the other hand areas under all land types exhibit decrease by amounts ranging from 54 to 82%. For the barrage in addition to the dam, Fa area slightly decreases, Fl type slightly increases and the other land classes remain unchanged. Finally, the changes in land type, cropping pattern and fisheries in the selected bee I wetland were analyzed. Results of simulation indicate that some modification in land type in the selected Clmnia bee I wetland area in monsoon is likely to take place due to dam. Fa land type remains unchanged, F2 type decreases by about 17%, F3 type disappears, and FI appears which was nonexistent before. However in pre- and postmonsoon seasons, no change in land type is indicated. Obviously due to change in land type there will be some change in cropping pattern. Area under local Boro may reduce, some areas may become suitable for broadcast and HYV Aus and Rabi crop. This provides some indication about the qualitative changes in cropping pattern but evaluation of the changes in the amount of production could not be done within the scope of this study. As the deep water area is likely to be reduced, survival of fish requiring such habitat will be difficult. Habitat type for carp, catfish, and eel fish species may be reduced. River and flood plain flow simulation performed in this study were based on an assumed inflow hydro graph at Amalshid based on preliminary information available from some reports. No statement was available as to how much water is proposed to be stored or diverted by the Tipaimukh dam and/or the Fulertal barrage. There is much scope to improve this type of analysis if information about the operating rules and flow regulation become available.
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    Experimental and Numerical Investigation on Wave Interaction with Submerged Breakwater
    (Department of Water Resources Engineering, 2011-01) Silwati Al Womera; Ataur Rahman, Dr. Md.
    In this research work the interaction between waves and rectangular submerged breakwater has been investigated. To investigate the performance of proposed rectangular type submerged breakwater, experimental studies are carried out in a two-dimensional wave flume (21.3 m long, 0.76 m wide and 0.74 m deep) at the Hydraulics and River Engineering Laboratory of Bangladesh University of Engineering and Technology. A set of experiments are carried out at 50 cm still water depth with fixed submerged breakwaters of three different heights ( 30 cm, 35 cm and 40 cm) for five different wave periods (1.5 sec, 1.6 sec, 1.7 sec, 1.8 sec and 2.0 sec) in the same wave flume. For 15 run conditions, data of water surface at different locations are collected manually by providing a vertical scale on the flume side made of glass. Six different locations both in front of and behind the breakwater are selected for data collection. Also the type of wave breaking and position of wave breaking are simultaneously recorded with a digital video camera. Effects of breakwater height and length along the wave direction on wave height reduction are analyzed. Two-dimensional numerical model based on the SOLA-VOF method developed for wave interaction with floating breakwater has been updated in this research to study the wave interaction with fixed submerged breakwater. The SOLA-VOF model allows an efficient tracking of the free surface. It is based on the concept of a fractional Volume Of Fluid (VOF) for tracking free surface boundaries using the donor–acceptor approximation algorithm. The treatment of the free surface configuration using a single VOF function F is computationally very efficient. The SOLA scheme is employed to calculate the pressure and velocities in each time step and the added dissipation zone method is adopted to treat the open boundary. The basic equations used for VOF method are the continuity equation, the Navier-Stokes equation for incompressible fluid and the advection equation representing the behavior of the free surface. Because the wave generation source is placed within the computational domain, these equations involve the wave generation source. The developed numerical model is verified by comparing the model generated wave with the wave as per Stokes 3rd order wave theory. The time series water surface profiles, water particle velocity field, VOF function F, pressure around a breakwater of different heights (20 cm, 25 cm, 30 cm, 35 cm and 40cm) are simulated using the numerical model. The experimentally measured data shows good agreement with the water surface profiles and breaking positions simulated by the developed numerical model. This study is expected to serve as a useful model to analyze wave deformation due to submerged breakwater and will be important for designing submerged breakwater as a coastal protection measure.