Current World Environment

Introduction

Remote sensing application is wide in all fields especially on aspects of surface covering a large area. Surface feature is very useful for morphometry of particular area of interest in terms of drainage. Remote sensing application using software Arc GIS is very useful analyzing the relationship between runoff, geomorphic and geographic characteristics for morphometry of drainage. The quantitative analysis of watershed gives us an idea about many hydrological aspects. Lithology, slope pedology plays a major role to form watershed. This paper will explain a detail hydrological aspects study area taraka watershed at district Mysore, Karnataka covers 429 km². Arc GIS maps will be better tool to understand the particular area under study of morphometry on watershed expressed as quantitative analysis description of the drainage pattern in watershed. The establishing of drainage pattern on the behavier of the hyrological system of the watershed area. The quantitative discription and analysis of land forms of drainage basin. The  assessment grondwater management groundwater potential zones and physical changes in nature respones over time on drainage system by human impact. A classification of watersheds based on stream oders was first conducted by Horton, which later explained by Strahler(1952)

Material and Method

The GSI topographic map of the 1:50,000 scale map were utilized for delineating the study area. Software using the ArcGIS 9-2.The main concept of the drainage basin are order and length of stream, bifurcation ratios and length of the overland flow(chow,1964;padmini), this is strahler stream classification system.

The basic parmeters are area (A), Stream length (Lu), perimeter(p), watershed length (L), Stream order (Nu) are found out from the watershed map. The diferrent parameters such as Stream length ratio (Rl), Ratio of Bifurcation (Rb), Stream frequency, (Fs), Density of drainage (Dd), Infiltration number (If), Form of factor (Rf), Ratio of Elongation (Re). Circularity ratio (Rc).

Study Area

The Taraka water basin is a part of the river Cauvery basin in the H D KoteTaluk, Mysore District of Karnataka. It is located between 12^o00’ to 12^o15’ North latitudes and 76^o5’ to 76^o25’ East longitudes. Taraka watershed, Mysore district, Karnatak state southern part and It comprises of 10 sub-watersheds. The area of study is 429 sq km². According to Survey of India 57D/4, 57D/8, 58A/1 and 58A/05 are the toposheet number. The study area connected with an all-weather motorable road (Fig.1 and 2). River Cauvery is towards North and H D Kote towards South zone shown in Fig.1. The average rainfall is about 560mm.

Figure 1: Location Map using Arc GIS. Click here to view Figure

The Lithology of the Area

The taraka watershed is a Proterozoic western block of southern part of Karnataka. Amphibolite Schistose rock of granulite facies of metamorphism which divides the Amphibolite Schist and Granitic Gneissic rocks of Archean age. This area is a typical hard rock terrain (Fig.2 and 3).

Figure 2: Lithology Map of the Area. Click here to view Figure

Morphometry Analysis

Morphometry was a tool for the measurement and calculative method of analysis to get the quantified values on the surface, shape and dimension of the land. The Taraka watershed is composed of ten sub watershed showing sub-dendritic from dendritic patterns.

Drainage

The procedure by which the water of an area flow off on surface streams or subsurface condition. Natural and artificial methods for effecting discharge of water by surface and subsurface system followed by passages termed as drainage. Geological structure and the natural condition of the soil are the controlling for system flowing movement pattern like vertical and horizontal. Drainage pattern of study area was prepared by toposheets, the 5.8 m spatial resolution and interpretation keys are tone, pattern, texture, and association.

Results and Discussion

Stream Order

The easiest, simplest and widely used numbering is the first tributaries rank of 1 first-order and followed second-order was defined under junction of two first-order streams (Strahler, 1964). In the same 3^rd and 4^th order will form in Taraka watershed. The stream order was studied 10 sub watersheds of study area. Total 669 streams are present. Out of 10 sub watershed were 5 fifth streams order, 3 were 4^th orders of stream, 1 were third and second order streams. First order of stream is present in all 10 sub watershed in an area (Table-1)

Figure 3(a): Stream Order at the Area. Click here to view Figure

Stream Length

The linear length of river stream is calculated using ARC GIS data analysis techniques. In all watershed first-order which that as streams are lengthier than other which that as the orders of stream increases as the linear length of streams decreased (Horton, 1945). Natural gravity and instable slopes in a place shows this kind of characteristics. The length is high in sub watershed 1 is about 89.59 km and least at sub watershed 6 of 5.861km (Table-2)

Mean Stream Length

Mean length-Lu, of mean channel segment in stream order of u is a dimension property of revealing the size of characteristic the component on a network of drainage and its contributing basin surface (Strahler-1964). To calculate the Total length of channel order of u, total length is divided by the number of segment Nu of that order (Table-3).

Bifurcation Ratio

Bifurcation ratio (Rb) means ratio of stream order to consecutive next order of streams. The 1^storder stream doesn’t have tributaries. The 1^st and 2^nd order streams received by 3^rd order streams as tributaries (Schumn, 1956). The 1.06-18.99 value ranges in bifurcation ratio shows the drainage pattern was influenced the geological features and structures. The high value shows stronger geological structures with good topography (Table-4).

Drainage Density

The degree of drainage characterized by development within the basin, purely in qualitative terms such as well-drained and poorly drained are commonly used (Horton, 1945). The controlling factors are length of streams, weathering resistance and rock formations, permeability apart from vegetation and climate. High density drainage is represented in the regions of impermeable and weak and subsurface of hilly regions. The values ranges 0.87-1.29 density of drainage at area was fall under low density (Table-4)

Figure 3(b): Drainage Density at the Study Area. Click here to view Figure

Stream Frequency

It is explained (Horton, 1932) as the stream segments total in number of all total orders per unit area. The values range from 1.31-1.76. The entire 10 sub-watershed indicates fractures controlled channel (Table 3).

Drainage Texture

As per the definition of Smith, 1950 explained in terms of very coarse, coarse and fine texture. The watershed number 3, 5, 6, 8, 9 and 10 were very coarse. Watershed number 2, 4, 7 were coarse texture. Fine texture was absent as per the calculation (Table.4).

Elongation Ratio

It means analysis the basin shape (Schumn, 1956). The values were generally from 0.71 to 1.2. It means geological and climate condition plays a major role. Range from 0.71-1.2 is usually steep slope and high value of relief (Table.4).

Form Factor

The form factor Rf, which are the dimensionless total area of the basin ratio, can be used to indicate the drainage basin of outline shape is quantitative expression of A_u of the square of basin length L_0,.The area of the ratio square of the streams length.(Horton, 1945). The values ranges from 4.50-20.61 the basin is almost narrowed length basin (Table.4)

Circularity Ratio

As per the definition of Miller (1953), “The ratio0f circularity  is expressed as the ratio of the area, The basin area of the circles whose perimeter is equal to the basins of the perimeter” as mentioned in the Table 1. It means stream frequency and stream length. The circularity ratios values Varied from 0.21 –0.73 elongated basin in shape wise.

Length of the Overland Flow

The water flow average length on surface before it became a stream it might be horizontal and drainage divides point finally drains to a same point(Horton, 1945). This is nothing but reciprocal of density of the area drainage. The surface flow water values varied from 0.38 to 0.63. The lithology and physiographic conditions are controlling factor.

Figure 3(c): Map of Sub-Watersheds. Click here to view Figure

Figure 4: Sub-Watershed Map of the Study Area. Click here to view Figure

Table 1: Parameter of Morphometric and Methodology of Morphometric.