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Rahman M.M.,Ministry of Water Resources | Sarkar S.,Indian School of Mines | Rai R.K.,DHI India Water and Environment Pvt. Ltd
Journal of Hydrologic Engineering | Year: 2013

Bangladesh is a flood prone country where huge damages take place every year. Therefore, to minimize flood extremes, it is important to control the flood peaks at the upstream area through suitable watershed management practices. The flood control management at the watershed scale requires good quality flood data. However, in developing countries like Bangladesh, such hydrological information is rarely available at the watershed level. Under such circumstances, it is important to use a hydrological model representing the rainfall-runoff process to arrive at the extreme flows in the rivers, which require extreme rainfall data as a major inflow to the hydrologic system. Furthermore, the density of rain gauges in Bangladesh is low and the quality of available flood data is poor. Considering this, it is important to develop regional extreme rainfall maps for the reliable estimation of flood flows in the river by using a suitable modeling approach. Therefore, in the present paper, an attempt has been made to derive the regional best fit extreme rainfall pattern for Bangladesh for the estimation of extreme rainfall quantiles. This study uses the annual maximum daily rainfall of 68 rain gauge stations. An autocorrelation test isapplied to test the independency of the data. Later, considering the heterogeneity in the hydroclimatic and topographic details, entire rain gauge stations have been clustered into six hydroclimatically homogeneous regions; namely, northeast (NE), northwest (NW), southeast (SE), southwest (SW), coastal, and central regions, by using the k-mean clustering technique. The stations that did not pass the discordant and heterogeneity test were discarded from the regional frequency analysis. For regional frequency analysis, the L-moment method was applied. Based on the ZDIST goodness of fit test and the L-moment ratio diagram, the generalized extreme values distribution was identified as the best fit for the SE, NW, and coastal regions. However, for NE, central, SW regions, the best fit distributions were generalized logistic and generalized Pareto, respectively. Using the derived distributions, regional extreme rainfall quantiles were estimated, followed by geo-mapping in ArcGIS 9.2. © 2013 American Society of Civil Engineers.

Sinha M.K.,Ministry of Water Resources
Water and Energy International | Year: 2015

Water is essential for everybody’s life, living and livelihood. It is this unique reach, which makes water a most effective means to achieve inclusive growth. It fulfils most basic human and ecological needs and is indispensable to almost all economic activities, including agriculture, energy production, industry, and mining. With impacts on health, gender equity, education and livelihood, water management and water resources projects are crucial to sustainable economic development and the alleviation of poverty. Since beginning of the civilization, water resources projects have contributed towards all round development of the region. But sometimes these projects lack holistic approach thereby inviting criticisms for skewed and lopsided developments along with concerns for environment and displacement of inhabitants of the submergence area. While the command area benefit from irrigation, water supply, etc., people from submergence area not only lose their land and/or livelihood but also their social networks. Similarly, implementation of environment safeguard measures and resettlement & rehabilitation measures often raise several questions. In the process, the opportunity for inclusive growth is not utilized fully. There is a need to learn from implementation of large projects, such as Tehri HE Project, Sardar Sarovar (Narmada) Project, etc., so that proper policy perspectives emerge towards achieving inclusive growth. These experiences and best practices were also corroborated during consultation meetings for National Water Policy (2012), which helped in evolving some policy recommendations in this regard. This paper makes an attempt to present these best practices and policy prescriptions so that project authorities may adopt these and make large water resources projects more beneficial and contribute towards achieving inclusive growth. © 2015, Central Board of Irrigation and Power. All rights reserved.

Dhari S.,Ministry of Water Resources | Arya D.S.,Indian Institute of Technology Roorkee | Murumkar A.R.,Indian Institute of Technology Roorkee
Applied Geomatics | Year: 2014

Sinuosity and river shifting analysis of the Ganges River in Uttarakhand plains between Haridwar and Balawali has been done using topographic maps and various Landsat images during 1972 to 2005. The transect method was used for the river shifting measurement. The study area consists of a stretch characterized by uneven meandering and shifting. Consequently, the adjacent areas are susceptible to frequent flooding that causes significant losses of crops, property, livestock, and human lives. During the study period, different channel patterns were observed such as straight single-channel river, braided multi-channel river, etc. It was found that the west bank of the Ganges River was subjected to more erosion and that the river is shifting towards the west. The width of the meander belt ranged from 1 to 3.5 km with an average of about 2 km. Based on the findings of this study, it is suggested that the flood protection structures are crucial for the west bank. It is further suggested that these structures be constructed outside the meander belt of the river. © 2014, Società Italiana di Fotogrammetria e Topografia (SIFET).

Rahman M.M.,Bangladesh Water Development Board | Arya D.S.,Indian Institute of Technology Roorkee | Goel N.K.,Indian Institute of Technology Roorkee | Dhamy A.P.,Ministry of Water Resources
Journal of Hydrologic Engineering | Year: 2010

A case study was conducted in the Teesta subcatchment in Bangladesh for determining design flood flows and corresponding flood stages for different return periods using frequency analysis and MIKE 11 model. Different distribution functions of frequency analysis were tested for their goodness of fit. The observed discharge data at Kaunia on the river Teesta were used for estimation of design flood. The Pearson type-III distribution was found best fitted by the Kolmogorov-Smirnov, D-index, and L-moment diagram ratio tests, and accordingly 25-, 50-, and 100-year return period design floods were computed. The river network of Teesta River was extracted from SRTM 90-m digital elevation model. The river network of Teesta subcatchment was then simulated by MIKE 11 rainfall-runoff Nedbor-Afstromnings-Model (NAM) and HD model. The resultant time series of river stage was then compared with corresponding observed values. From the model, a stage-discharge relationship (Q-h) curve and respective equation were developed for Kaunia station on the river Teesta. The developed equation determines the corresponding flood stage of estimated flood flow of 25-, 50-, and 100-year return periods. The resulting flows and stages will be useful to design hydraulic structures, prepare flood extent maps, assess vulnerability of flood damage for different return periods, and provide flood forecasting for early warnings of floods. The approach presented would be applicable to similar river basin systems where data are limited and scarce. © 2011 ASCE.

Adhikari K.R.,Tribhuvan University | Tan Y.C.,National Taiwan University | Lai J.S.,National Taiwan University | Chen Z.S.,National Taiwan University | Mishra V.S.,Ministry of Water Resources
Irrigation and Drainage | Year: 2013

Drawing results from multi-scale studies, this paper addresses the important coexistence between the Chitwan National Park and buffer-zone farmers' communities in the East Rapti River basin of Nepal. The relationship between the two is discussed using results of land use change (1978-2010) and water availability analysis (1976-2010). At basin level, though there are indications of losses of the government forest, the utilizable outflow of water in the river is still abundant because the process of depletion of water is very low. Scaling down to local level, irrigation systems originating in the river were evaluated and farmers interviewed across locations. There were statistical differences in irrigation system performance affecting water availability for crop production in the buffer zone. Because irrigation plays a disproportionately greater role in farm income and economic water scarcity could be removed, improvement in access to irrigation could effectively help improve food sufficiency and reduce income disparity in this basin. In the forest of the national park, encroachment seems to be low but frequencies of rhino poaching and timber pilferage have remained relatively high. As the buffer zone is the gateway to the park, and subsistence farm families live on the fringes of the park, helping irrigation development would strengthen farmers' cooperation in enhancing resource conservation of the park. © 2013 John Wiley & Sons, Ltd.

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