Geo-Analyst , ISSN 2249-2909 July, 2016
MORPHOMETRIC ANALYSIS AND HYDROLOGICAL BEHAVIOUR OF BRAHMANI RIVER BASIN, JHARKHAND AND WEST BENGAL, INDIA
Rupen Mal * nd Prof. V.C. Jha **
Abstract
The analysis of drainage basin morphometryhas been undertaken to assess the hydrological behavior of the Brahmani river basin comprising eastern part of Chhotanagpur plateau. In this area, a large number of stream segments are originated from the Chhotanagpur plateau region and flow to the east ward and finally joined to the Dwarkariver in Murshidabad district. Rain water significantly provides to the evolution of drainage pattern in this basin area. Quantitative Morphometry plays a vital role for the analysis of hydrological behavior as well as processes. The morphometric analysis of this river basin was done by the geospatial technique. The analysis expresses that the entire study area is lithologically uniform and structurally permeable. As, the high drainage density of different sub watersheds indicate more surface runoff. Morphometric analysis indicates that the study area is more active for weathering due to very coarse to moderate drainage texture. The drainage pattern of all the watersheds is dendritic to sub dendritic in this basin. The high bifurcation ratios are highly controlled the structure on drainage pattern. The elongation and circulatory ratios showed that all the sub watersheds have elongated to circular shapes. Integrated analysis of morphometric parameters reveals that an important hydrological behavior of all the 12 sub watersheds which could be supposed.
Keywords: Morphometry, Hydrological Behavior, Drainage Density, Drainage Texture .
Introduction
The term Morphometry is defined as the measurement and mathematical analysis of the configuration of the earth surface, shape and dimension of its landforms (Agarwal, 1998; Obi Reddy et al. , 2002; Pakhmode et al. , 2003). The different quantitative methods have been developed to understand the behavioral characteristics of the drainage pattern of a basin (Leopold & Maddock 1953; Abrahams,1984). In the field of hydrology, drainage characteristics are the fundamental parameter for understanding of the hydrological processes operating at the watershed scale. In hydro-geomorphology, watershed is considered as the indispensable unit to study the
*Research Scholar, Department of Geography, VisvaBharati, Santiniketan, W.B., India and Junior Geographical Assistant, NATMO, Govt. of India
**Professor, Department of Geography, VisvaBharati, Santiniketan, W.B., India
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hydrological processes,erosional landscape. It is the fundamental units of fluvial landform and helps to find out the watershed geometric characteristics like, stream network, drainage pattern and drainage texture (Abrahams, 1984). Hydrologic as well as geomorphic processes are operating within the watershed and the morphometric analysis of the micro level watershed reveals the idea about the formation and development of land surface processes (Singh, 1992; Dar et al. , 2013). Different hydrological processes such as basin travel time, time to hydrograph peak and intensity of erosional processes occurring in the watershed scale which can be predicted the better accuracy from the morphometric evolution of a watershed. Morphometric analysis of watershed provides the very good information relating to soil, geology and geomorphology to understand the controlling factor of hydrological behavior (Romshoo et al. , 2012). There are found the practical application of quantitative morphometric analysis i.e. river basin evolution, soil characteristics, water and natural resources conservation and management. Morphometric analysis of watershed gives a quantitative description of drainage system and characterization of watershed (Strahler, 1964).Using the various conventional methods or techniques, the morphometric characteristics of river basins and sub basins in different part of the world has been carried out (Strahler,1964;Strahler, 1957). Now a day, the assessment of drainage basin Morphometry has becomemore accurate and precise due to the development of computer technology and geospatial techniques. While now a days, evolution of GIS techniques, morphometric parameters of drainage basins are evaluated through the easy and accuracy methods. The satellite data and GIS techniques gives the greater success to generate the data of spatial deviation and necessary hydrological condition for watershed management (Das & Mukherjee 2005; Vittala et al. , 2004; Nag, 1998). GIS is the powerful tools to manipulate and analysis of spatial data and provides the very good environment for morphometric analysis. In this present study, the morphometric characterization of 12 sub watersheds of Brahmani river basin was prepared in the GIS environment (Altaf et al. , 2013). Morphometric analysis of the Brahmani river basin lies in the fact that this river basin forms the irrigational and economic development of this region. As the Brahmani river is a non- perennial river and flow character is seasonal in nature. So, the contribution of rainfall largely helps to evaluate the drainage lines in this area. Therefore, the comparative study of different quantitative morphometric parameters of river basin will definitely help to understand the geomorphological impact on the spatio-temporal change of the hydrological function. Some important morphometric parameters such as bifurcation ratio and circularity ratio are the input parameters for the hydrograph analysis (Esper, 2008; Bhagwat et al. , 2011; Bhaskar et al. , 1997; Jain et al. , 2000) and also the evaluation of surface water potentiality of this region (Suresh et al. , 2004). It is said that, the study of morphometric analysis has greater impact for understanding the hydrological behavior of the study area it influences the socio-economic aspects of the Brahmani river basin.
Location and Geographical Background of the Study Area
Brahmani river, the main tributary of Dwarkariverspreads its network within the Jharkhand (Dumka and Pakur district) and West Bengal(Birbhum and Murshidabad district) state of Eastern India.The valley of this river starts from Chotonagpur plateau proper hilly terrain to the gangetic
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Geo-Analyst , ISSN 2249-2909 July, 201 6 plain of the Murshidabad district. The River basin extends from 24°09 ΄24 ΄΄ N. to 24°29 ΄31 ΄΄ N. latitudes and 87°17 ΄39 ΄΄ E. to 88°00 ΄58 ΄΄ E. longitudes covering an area of about 1163.69 km², extending from the Chhotanagpur plateau fringe in the West to moribund delta in the East. River Pagla which delimits the northern boundary of the region and Dwarka River delimits the southern boundary. The catchment area is bounded by the district boundary of Murshidabad in the East, Dumka in the West, Pakur in the North, and Birbhum in the South.Administratively, the study region comprises 14 CD Blocks namely, Jama, Ramgarh, Dumka, Gopikandar , Kathikund, Shikaripara, Pakuria, Maheshpur(Jharkhand); RampurhatI,RampurhatII,Nalhati I and Nalhati II, Khargram and Nabagram(West Bengal).There are 12 major sub watersheds among which 7 are in the left sides and 5 are in the right side of the main water course.Hydrologically the left side tributaries are much more active than the right side tributaries. The main source of water of river Brahmani is the rain. Sub-tropical monsoonal climate and deciduous forest characterize the region with weather extremit y and seasonal concentration of rainfall.
Fig. 1: Showing the location of the study area
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Materials Used
To demarcate the river basin and thereby to perform morphometric measurement, subsequent mapping and analysis Topographical maps of the Survey of India (SOI) [73P/7, 73P/8, 73P/11, 73P/12, 73P/15, and 73P/16and78D/4] at the scale 1:50,000 have been used. The Morphometric analyses have been undertaken by dividing the entire basin into several grids with 1 sq. km. grid area. ESRI Arc GIS, softwares have used for spatial mapping purpose.
Methods
Generation of drainage
The drainage line was generated from the survey of India topographical maps at1: 50000 scales in the GIS environment .The GIS software i.e. Arc GIS was used for generation of drainage which is more logical and perfect when it is compared to the manual process (Engelhard et al. , 2011 ).The Natural drainage lines present in SOI toposheets were digitized and used to manipulate from the SRTM DEM. For the actual determination of flow direction and flow accumulation DEM have beenused. The 12 sub watersheds boundaries were identified by the highest point where the two different drainage lines were drained opposite to each other. As a result, the watersheds boundaries were prepared (Figure 1) and the whole basin boundary was also prepared. Area of each sub watersheds wasfound out through the polygon preparation in Arc GIS software in the GIS environment. On the other hand, the length of the watershed was calculated by summing the length of the main stream channel and the distance from the top of the main channel to the watershed boundary. By summing the lengths of all stream segments in each sub watershed the total stream length was calculated.
Quantitative Morphometric measurement:
In this study, morphometric analysis of the different parameters, i.e. stream order,stream length, bifurcation ratio, relief ratio, drainage density, drainage intensity, drainage texture, drainage frequency,drainage texture, form factor, length of overland flow, constant channel maintenance, circulatory and elongation ratio,area, perimeter, and length of all the 12 sub-watersheds havebeen carried out using the standard mathematical formulagiven in the Table 1 (Strahler,1964;Strahler,1957;Suresh etal. ,2004;Horton,1945;Schumms,1956;Horton,1932;Miller,19 53;Faniran,1968). The values of various sub-basin characteristics required for calculating the morphometric parameters which are shown in the following table 1.
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Table 1: Showing the Methodology for Calculating the Morphometric Parameters
Sl. Morphometric Formulae/ Laws References No Parameters 1 Stream Order ( ) Hierarchical Ranking of streams (Strahler,1964) 2 Stream Length(Lu) Length of the stream (Horton,1945)