International Journal of Civil, Structural, Environmental and Infrastructure Engineering Research and Development (IJCSEIERD) ISSN 2249-6866 Vol. 3, Issue 3, Aug 2013, 77-86 © TJPRC Pvt. Ltd.

MORPHOMETRIC ANALYSIS OF THE VAMSADHARA RIVER BASIN USING SPATIAL INFORMATION TECHNOLOGY

E. AMMINEDU, K. HARIKRISHNA, CH. VASUDEVA RAO, G. JAISANKAR & V. VENKATESWARA RAO Department of Geo-Engineering, College of Engineering (A), Andhra University, Visakhapatnam, ,

ABSTRACT

Drainage characteristics playing a key role for watershed development and management plans for harnessing surface water and ground water resources. This study was undertaken to determine the drainage characteristics of Vamsadhara river basin (VRB). The study area with an qareal extent of 10,601.5 km2 is forms a part of Orissa and Andhra Pradesh states. Spatial Information Technology (SIT) i.e. Remote Sensing (RS) and Geographical Information System (GIS) has proved to be an efficient tool in delineation of drainage pattern. GIS and image processing techniques have been adopted for the identification of morphological features and analyzing their properties of the Vamsadhara river basin (VRB). The basin morphometric parameters such as linear and aerial aspects were determined and computed.

The significance of the morphometric characteristics in various sub-basins and for the whole basin, have been highlighted. It is 8th order drainage basin and drainage pattern mainly in subdendritic to dendritic type. The streams of lower order mostly dominate the basin. It is observed that the drainage density value is high which indicates the basin is less permeable subsoil with sparse vegetative cover. The circularity ratio value reveals that the basin is strongly elongated and less permeable homogenous geologic materials. This study would help the local people to utilize the resources for sustainable development of the basin area.

KEYWORDS: Vamsadhara River Basin, Morphometry, Water Resources Management, Spatial Information Technology

INTRODUCTION

India is traversed by large number of big and small river systems. Drainage basins or basins should be the study area for the better understanding of the hydrologic system. The optimal and sustainable development of the resource is prerequisite so that it is assessed rationally to avoid any future problems regarding its qualitative and quantitative availability. The rain in India is concentrated in a short period of about five monsoon months (June to October). On account of high precipitation as well as wide variation in its intensity and the areal distribution, several rivers swell up in high floods during this period. The coastal belt of India especially the area of Orissa, Andhra Pradesh and get flooded in association with the pre- and post-monsoon cyclonic storms forming in the .

This calls for proper management of water resources of the area, for which knowledge of the basin hydrology of the river, which drains through the area, is essential. Morphometric analysis (Agarwal et al., 2000) is an important aspect of hydrological and hydrogeological studies. The basin morphomatric characteristics of the various basins have been studied by many scientists using conventional (Horton, 1945; Smith, 1950; Strahler, 1957) and remote sensing and GIS methods (Krishnamurthy and Srinivas, 1995; Biswas et al., 1999; Narendra and Nageswara Rao, 2006). In this connection morphometric characteristics of the drainage basin of the area may provide some useful inputs in understanding the basin hydrology. So far, there has not been any work on these lines for the area under study and hence, the need for the present study. 78 E. Amminedu, K. Harikrishna, Ch. Vasudeva Rao, G. Jaisankar & V. Venkateswara Rao

STUDY AREA

Vamsadhara River Basin with an aerial extent of 10,601.5 Sq.kms. is taken up for the examination of the problem. The river is prone to frequent floods. This is an inter-state drainage basin between Andhra Pradesh and Orissa. The river joins the sea at after traversing 230kms. in both the states (Figure 1). The basin area forms a part of Survey of India topographic sheets Nos. 65M/5-16, 65N/9, 65N/13-15, and 74A/1-8 and B/1-3 and 74B/5. The basin area is located between 830 15′ and 840 57′ E longitude and 180 15′ and 190 57′ N latitude (figure 1).

Figure 1: Location Map of Vamsadhar River Basin

The basin is divided into 19 sub-basins based on the drainage network. Most part of the plains is covered by charnkites in the eastern and lower central parts. The hills along the northen parts and eastern parts composed by khondalites and granite gneisses. The soils of the study area consisting of clay mostly in central area and sands and silts in the remaining basin area. The annual rainfall of the study area varies from 980 in south to 1300mm towards north. This is due to the proximity of the northern parts of the study area to the .

DATA BASE AND METHODOLOGY

Drainage network and sub-basins are delineated from 28 survey of India topo sheets of 1:50,000 scale, using Arc GIS 9.3 and ERDAS IMAGINE 9.1 softwares formed the data base for the study. The digital data of AWiFS with 56 m spatial resolution was used to meet the requirement of area under study (Figure 4). The variables for the study of morphometric aspects were analysed using standard techniques followed by several pioneers in the field such as Horton(1945), Schumm(1956), Strahler (1964) etc. For the convenience of the study, the area was divided into smaller units viz., sub-basins. 19 sub-basins were demarcated and the analysis was carried out for each of them and for the whole of the basin. The order was given to each stream by following Strahler (1964) stream ordering technique. The attributes were assigned to create the digital data base for drainage layer of the river basin. The map showing drainage pattern in the study area was prepared after detailed ground check with GPS survey on channel network and water tanks. Various morphometric parameters such as linear aspects of the drainage network like stream order (Nu), bifurcation ratio (Rb), stream length (Lu) and areal/density aspects of the drainage basin like area(A), drainage density (Dd), stream frequency

(Fs), texture ratio (T), elongation ratio (Re), circularity ratio (Rc) and form factor ratio (Rf) of the basin were computed.

RESULTS AND DISCUSSIONS

Various morphometric parameters of VRB is calculated in ArcGIS-9.3 and is summarized in tables. Morphometric Analysis of the Vamsadhara River Basin Using Spatial Information Technology 79

The basin area is divided into 19 sub-basins (Figure 3) and 6 seventh order sub-basins out of 19 sub-basins.

Linear Aspects

The data obtained for the various parameters of linear aspects have been presented in Table No.1 and the same have been analyzed in the following sections.

Stream Order (Nu)

Drainage basin analyses begin by designation of stream orders. The channel segment of the drainage basin has been ranked according to Strahler stream ordering system using ArcGIS-9.3 The study area is a 8th order drainage basin. As a general rule, the number of stream segments decrease as the stream order increases for the river, as well as, for the sub- basins. The total number of stream segments of all orders was found to be 45,627.

Of this, the first order stream segments are 35,341, which accounts for 77.45%, 7,920 are 2nd order which amounts th 17.36%, 1,814 are 3rd order which is 3.97%, 421 in 4 order which is 0.09% and 109,22 and 6 are

Figure 2: Drainage Patterns of the Vamsadhara River Basin

Figure 3: Sub Basins of Figure 4: AWiFS Satellite Imagery of Vamsadhara River Basin Vamsadhara River Basin 80 E. Amminedu, K. Harikrishna, Ch. Vasudeva Rao, G. Jaisankar & V. Venkateswara Rao

5th, 6th and 7th order streams respectively (Table 1 ). The percent of first order streams are found to be more respectively in sub-basins 7, 17, 12, 2 and 1. All these sub-basins flow through the hilly terrain for major part of their course. The percent of the first order streams to the total number of stream segments was found to be low in sub-basins 18 and 19 because these are lying in coastal plains.

Table 1: Number of Streams and Lengths of Streams of 19 Sub Basins of VRB Sub No. of Streams Length of Streams (km) Basin N N N N N N N ∑N L L L L L L L ∑L No. 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 3916 841 197 43 11 2 1 5010 1124 466.9 221.5 119.5 75.4 20.4 17.5 2045 2 4040 904 202 45 12 4 1 5207 1127 452.7 178 85.9 44.7 38.2 16.9 1943 3 2888 598 130 34 8 1 - 3659 789.6 289.4 122.5 52.6 27.6 31.4 - 1313 4 877 167 43 9 1 - - 1097 213.4 88.9 34.5 18.5 3.1 358.4

5 878 201 45 11 2 1 1138 238.6 102.2 44.3 11.4 17.6 9.5 423.6

6 840 188 41 10 4 1 1084 205.9 83.7 38.3 15.2 7.6 11.7 362.4

7 7516 1692 380 86 22 4 1 9700 1942 874.6 345.9 159.2 75.7 38.6 52.7 3489 8 284 68 21 4 1 378 114.6 41.6 19.7 9 4.4 189.3

9 303 75 24 5 2 409 89.7 51.8 28.3 11.8 9.2 190.8

10 779 165 37 8 2 1 992 263.9 96.9 41 22.8 6.4 18.5 449.5

11 1543 323 69 19 6 2 1 1962 473 187.3 80.2 59.5 10.8 9.6 12.4 832.8 12 4314 1048 238 60 18 4 1 5682 1359 539.3 247.9 112 36.6 39.1 49.9 2384 13 457 118 32 9 2 618 144 61.5 34.1 18.3 7 264.9

14 949 205 51 11 1 1217 269 128.8 59.8 26.9 12.5 497

15 514 96 24 6 1 641 149.3 56.7 34.1 12.4 8.9 261.4

16 78 174 41 9 2 304 228 105.1 50.7 20.6 19.5 423.9

17 4408 908 200 44 11 2 1 5573 1244 501.5 210.3 105.5 53.9 15.5 25.6 2156 18 307 47 12 1 367 59.5 25.9 11.3 1.5 98.2

19 450 102 27 7 3 589 112.5 53 28.1 8.2 9.5 211.3

Total 35341 7920 1814 421 109 22 6 45627 10146.1 4207.8 1830.5 870.8 430.4 232.5 175 17893.1

Stream Length

For the whole of the basin, the total stream length is17,893.1 km. of which, the first order stream length is 10,146.1km, which accounts for about 56% of the total stream lengh of the whole basin. The second and third order stream lengths are 4,207.8 km. and 1,830.5 km.(Table.1) which accounts for 23.5% and 10.2% of the total stream length of the basin, respectively. The stream lengths of the rest of the orders account for the remaining 10.3%.

Bifurcation Ratio

Horton (1945) defined bifurcation ratio as the ratio of the number of streams of an order to the number of streams of the next higher order. The mean bifurcation ratio computed for the VRB is 4.47. The bifurcation ratio values obtained for the sub-basins range from 3.54 (in sub-basin 11) to 7.48 (in sub-basin18). In a well developed drainage network, the bifurcation ratio value ranges between 2 to 5 (Horton, 1945 and Strahler, 1957). The bifurcation ratio values obtained for the sub-basins and for the entire basin reveal that the drainage network in the study area is in a well developed stage.

Areal/Density Aspects

The data obtained for the various parameters of areal aspects have been shown in Table No.2 and the same have been discussed below. Area of a basin (A) is the important parameters in quantitative morphology. The area of the basin is defined as the total area projected upon a horizontal plane contributing to cumulate of all order of basins. Basin area is hydrologically important because it directly affects the size of the storm hydrograph and the magnitudes of peak and mean runoff. It is interesting that the maximum flood discharge per unit area is inversely related to size (Chorley, et al., 1957).

The aerial aspects of the drainage basin such as drainage density (Dd), stream frequency (Fs), texture ratio (T), elongation ratio (Re), circularity ratio (Rc) and form factor ratio (Rf) were calculated and results have been given in Tables 2, 3 and 4. Morphometric Analysis of the Vamsadhara River Basin Using Spatial Information Technology 81

Basin Area

As mentioned earlier, the area of the entire basin is 10,601.5 km. Among the sub-basins, the sub-basin 7(1720.9 sq.km) occupy the maximum area (sq.km.) followed by sub-basin 12 (1329.2 sq.km), sub-basin 1(1295.4 sq.km.) and sub- basin 17(1202.4 sq.km). these four sub-basins occupies morethan fifty percentage of the total area of the basin. On the other hand, sub-basin no.8 (95.3 sq.km) was found to have the least area among all the sub-basins (Table 2).

Drainage Density (Dd)

An important indicator of the linear scale of landform elements in stream eroded topography is drainage density (Horton, 1945). An increase in the drainage density means a proportionate decrease in the size of individual drainage units, such as the first order drainage basin. A similar index known as the texture ratio is defined by smith (1950).

The drainage density of the study area is 2.65 km/ sq.km. This value indicates that for every square kilometer of the basin, there is 2.65 kilometer of stream channel. The classification system of Deju (1971) was used to express the drainage system. The drainage density is less than 0.5 per km for poorly drained basins and 0.5 to 1.5 per km for medium drained and more than 1.5 per km for excellent drainage type of basins. Drainage density is calculated for each sub-basin and the results are presented in Table.2. It is seen from the table that the drainage density is more than 2 per km for all the sub-basins except sub-basins 9, 18 and 19. The sub-basin 18 is poorly drained in comparison with the other sub-basins because of its high infiltration soils with very low relief. The high drainage density is obtained for the sub-basins 2, 3, 5-8 and 10. These are correlated with dense vegetation and relief.

Stream Frequency

Stream frequency is used as a supplementary, measure of the fineness of the texture of topography. It is associated with lithology, degree of slope, stage of fluvial cycle and amount of surface runoff. Computations on the stream frequency for the study area are shown in table.2, on sub-basin wise. High frequencies of more than 6 observed for the sub-basins 2, 3, 5 and 6 in the regions of non-homogenous bed rock and thick vegetative cover. The river basin shows almost a positive correlation between drainage density and stream frequency as inferred from the linear correlation coefficient value of 0.92.

Table 2: Sub Basin Areas, Stream Frequency and Drainage Density for Different Sub-Basins in Vamsadhara River Basin Sub- Area of Stream Drainage Classification Bifurcation Basin Sub-Basin Frequency Density (per of Drainage Ratio No. (Sq.kms) Number/ Sq.km.) Sq.km) (Deju, 1971) 1 1295.4 4.20 3.90 2.54 Excellent 2 830.9 4.08 6.30 3.76 Excellent 3 591.9 5.10 6.20 3.57 Excellent 4 195.9 5.72 5.60 2.95 Excellent 5 179.1 3.72 6.32 3.81 Excellent 6 178.2 3.92 6.10 3.27 Excellent 7 1720.9 4.45 5.64 3.26 Excellent 8 95.3 4.16 4.00 3.20 Excellent 9 210.0 3.61 1.95 1.46 Medium 10 210.4 3.96 4.72 3.44 Excellent 11 469.6 3.54 4.18 2.85 Excellent 12 1329.2 4.05 4.28 2.89 Excellent 13 196.4 3.90 3.15 2.17 Excellent 14 326.5 6.02 3.72 2.45 Excellent 15 171.8 4.83 3.73 2.45 Excellent 16 273.4 4.34 3.42 2.49 Excellent 17 1202.4 3.98 4.64 2.88 Excellent 18 587.1 7.48 0.63 0.27 Poor 19 536.1 3.88 1.10 0.63 Medium 82 E. Amminedu, K. Harikrishna, Ch. Vasudeva Rao, G. Jaisankar & V. Venkateswara Rao

Texture Ratio (T)

The texture of topography is the average size of the units composing a give topography. Values of drainage density and stream frequency for small and large drainage basins are not directly comparable because they usually vary with the size of the drainage area. The ratio for course, medium, fine and ultra-fine textured topography was suggested by smith (1950) and was followed for grading the texture in Vamsadhara.

The texture ratio and type are shown in Table.3. The variation in texture ratio varies from 2.99 to 36.94. The minimum and maximum are obtained for sub-basins 18 and 7 respectively. The maximum texture ratio obtained in the sub- basin 7 is due to the sparse vegetation in semi-arid type of climate with resistant rocks. A very low value of the sub-basin 18 is because of gentle slopes and flat topography with lesser rainfall intensity (Singh, 1979). According to the above classification the sub-basins 9, 18 and 19 fall under medium texture and sub-basins 2, 7 and 17 fall under ultra-fine texture. The remaining sub-basins have fine textured topography. Ultra-fine textured topography is observed in the above mentioned sub-basins with clay type of soils.

Table 3: Texture Ratio for Different Sub-Basins in Vamsadhara Sub- Texture Ratio Grade Basin (Number/ (Texture of the No. km) Topography) 1 27.35 Fine 2 33.17 Ultra fine 3 2.84 Fine 4 15.88 Fine 5 13.74 Fine 6 15.83 Fine 7 36.94 Ultra fine 8 8.87 Fine 9 5.89 Medium 10 11.17 Fine 11 19.27 Fine 12 25.48 Fine 13 7.87 Fine 14 13.41 Fine 15 8.64 Fine 16 10.69 Fine 17 33.64 Ultra fine 18 2.99 Medium 19 3.92 Medium

Elongation Ratio (Re)

The shape of the drainage basin is expressed by elongation ratio. It is defined as the ratio of diameter of a circle of the same area as the basin to the maximum basin length (Schumm, 1956). Utilization of this factor for shape evaluation has been referred by some of the Indian authors (Singh, 1979). Smaller the value, the more elongated is the shape of the basin and larger the value the more circular is the shape of the basin.

Table.4 indicates maximum values for the sub-basins 8,9,13 and 16. These high values indicate a tendency to circularity when compared to the other basins (Singh, 1979). Minimum value is obtained for the sub-basins 10(0.34), 12(0.38) and 5(0.37) which shows that these basins are comparatively elongated in shape. Other drainage basins show intermediate values. Singh (1979) considered basin elongation values as nearly equal to one for circular shapes. In the case of Vamsadshara all the sub-basins have less than 1. In all, the sub-basin 10 is more elongated in shape (0.335) and the sub- basin13 (0.99) is more circular in shape.

Morphometric Analysis of the Vamsadhara River Basin Using Spatial Information Technology 83

Circularity Ratio (Rc)

It is the ratio of the area of the basin to the area of a circle having the same perimeter (Miller, 1953). Basin circularity ratio is a non-dimensional parameter and provides a quantitative expression of the shape of the basin. Further, basin circularity ratio may be of practical use in predicting certain hydrologic characteristics of the drainage basin. It is associated with drainage pattern, drainage density, stream length, stream frequency and topography slopes (Sidhu and Pande,1974). Irregularities in the drainage basin, a function of relief and slope, increase the perimeter and thus decrease circularity ratio. Uniformity of circularity ratio provides a good check of the assumption that the area selected is free from systematic structural controls. The circularity ratio of the drainage basins are shown in table.4. It ranges from 0.31(sub- basin 7) to 0.66 (sub-basin 8).

Form Factor (Rf)

The ratio of the basin area to the square of basin length is called the form factor suggested by Strullaer (1968). The form factor of the VRB is 0.30 Km-1. It is used as a quantitative expression of the shape of basin form which is elongated. The form factor for all sub-basin varies from 0.11 – 0.84 (Table.4). This observation shows that the sub-basins are most of them are elongated. The elongated sub-basin with low value of Rf indicates that the basin will have a flatter peak flow for longer duration. Flood flows of circular sub-basins are difficult to manage than from the elongated. Among the VRB sub- basins; Sub-basin 13 with the form factor 0.84 seems to be nearly circular when compared to other Sub- basins of the drainage basins and Sub-basin 5 with the form factor 0.11 seems to be highly elongated when compared to other sub-basins.

Relation between Circularity and Elongation Ratio

It must be emphasized that circularity and elongation are not inversely related, though a basin with a low circularity may show a high elongation value (Dikshit, 1976). The linear correlation coefficient obtained for circularity and elongation is 0.93. Basins with large areas have a higher elongation. This is because the large basin perimeters, as they are crenulated, measure much more than the circumference of the circles with the same area (Dikshit, 1976).

Table 4: Shape of 17 Sub-Basins Obtained by Different Formulae Sub- Basin Basin Form Basin Circularity Elongation Factor No. Ratio Ratio 1 0.25 0.48 0.56 2 0.22 0.42 0.53 3 0.14 0.37 0.43 4 0.27 0.52 0.58 5 0.11 0.33 0.37 6 0.18 0.48 0.48 7 0.15 0.31 0.43 8 0.51 0.66 0.80 9 0.52 0.55 0.81 10 0.10 0.34 0.34 11 0.19 0.57 0.50 12 0.12 0.34 0.38 13 0.84 0.40 0.99 14 0.36 0.42 0.68 15 0.38 0.39 0.70 16 0.61 0.45 0.89 17 0.18 0.55 0.48 18 - - - 19 - - -

84 E. Amminedu, K. Harikrishna, Ch. Vasudeva Rao, G. Jaisankar & V. Venkateswara Rao

SUMMARY AND CONCLUSIONS

The quantitative analysis of morphometric parameters is found to be of immense utility in river basin evaluation, watershed prioritization for soil and water conservation, and natural resources management at micro level. The areal extent of VRB is 10,601.5 sq.km. and is divided into 19 sub-basins. Sub-basin wise quantitative analysis attempted includes stream orders, stream numbers, bifurcation ratios, elongation ratios, basin circularity, form factor, drainage density, stream frequency and texture ratio. The total number of stream segments of all orders was found to be 45,627 and order of the basin is 8th order. For the whole of the basin, the total stream length is17,893.1 km. of which, the first order stream length is 10,146.1km, which accounts for about 56% of the total stream lengh of the whole basin. The mean bifurcation ratio computed for the VRB is 4.47. The bifurcation ratio values obtained for the sub-basins range from 3.54 to 7.48. Higher values of bifurcation ratio indicate a mature topoghaphy which is the result of the process of drainage integration.

This basin enjoys excellent drainage density with value of 2.65 per km. The high drainage density is obtained for the sub-basins 2, 3, 5-8 and 10. High stream frequency of more than 6 observed for the sub-basins 2, 3, 5 and 6 in the regions of non-homogenous bed rock and thick vegetative cover. The texture ratio varies from 2.99 to 36.94 and major sub-basins 7 and 17 are falls under ultra fine texture; 1 and 12 with fine texture. The elongatin ratio of all the sub-basins have less than 1 and the sub-basin 10 is nearly elongated (0.335) and the sub-basin13 (0.99) is close to circular in shape. The circularity ratio of the drainage basins ranges from 0.31(sub-basin 7) to 0.66 (sub-basin 8). The form factor of the VRB is 0.30 which is used as a quantitative expression of the shape of basin is elongated. The form factor for all sub-basin varies from 0.11 – 0.84. Thus the present study brought out the characteristics of the drainage network for the entire VRB and the contributing sub-basins. The quantitative analysis has helped to understand some useful hydrological characteristics. The numerical data has further provided the opportunity to compare the drainage characteristics of sub- basins of the study area. The results obtained can serve as useful input for a comprehensive water resource management plan.

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