Akhila. P, Sakthivel. R, Matheswaran. S and Biju C · Akhila. P, Sakthivel. R, Matheswaran. S and...

MORPHOMETRIC ANALYSIS IN THE SELECTED BASINS OF CHALK HILLS OF TAMILNADU, INDIA

Akhila. P, Sakthivel. R, Matheswaran. S and Biju C

Department of Geology, Bharathidasan University, Tiruchirappalli, Tamilnadu, India

Abstract

The present study mainly concentrated on the quantitative analysis of drainage system based on the

morphometric parameters. It mainly represent the physical and morphological attributes that are employed in

synthesizing its hydrologic response in a basin. The knowledge of basin hydrology is very important for proper

management of water resources. The drainage characteristics have studied to evaluate their hydrological

behavior in the study area by analyzing topographical map and SRTM data. From the morphometric study it is

understood that the streams flowing in the study area is from high altitude, lithologically varied and moderately

steepy slopes. The basin morphometric parameters such as linear,aerial and relief aspects are quantified. In this

study area drainage patterns are very unique. The drainage architecture of the terrain indicates that the area is

controlled by prominent faults and lineaments.

Key words: Quantitative morphometric analysis, Linear aspect, Aerial aspect, Relief aspect

1. Introduction

Morphometry is the measurement and mathematical analysis of the configuration of the earth's surface, shape

and dimension of its landforms (Agarwal, 1998; Obi Reddy et al., 2002). A major emphasis in geomorphology

over the past several decades has been on the development of quantitative physiographic methods to describe

the evolution and behavior of surface drainage networks (Horton, 1945 and Abrahams, 1984). The source of the

watershed drainage lines have been discussed since they were made predominantly by surface fluvial runoff has

very important climatic, geologic and biologic effects. The morphometric characteristics at the watershed scale

may contain important information regarding its formation and development because all hydrologic and

geomorphic processes occur within the watershed (Singh, 1992). Morphometric analysis of a watershed

provides a quantitative description of the drainage system, which is an important aspect of the characterization

of watersheds (Strahler, 1964). GIS techniques are nowadays used for assessing various terrain and

morphometric parameters of the drainage basins and watersheds, as they provide a flexible environment and a

powerful tool for the manipulation and analysis of spatial information.

The drainage basin analysis is important in any hydrological investigation like assessment of groundwater

potential, groundwater management, pedology and environmental assessment. Hydrologists and

geomorphologists have recognized that certain relations are most important between runoff characteristics,

geographic and geomorphic characteristics of drainage basin systems. Various important hydrologic phenomena

can be correlated with the physiographic characteristics of drainage basins such as size, shape, slope of the

drainage area, drainage density, size and length of contributories etc. (Rastogiet al. 1976). Geology, relief and

climate are the primary determinants of running water ecosystems functioning at the basin scale (Mesa, 2006).

JASC: Journal of Applied Science and Computations

Volume VI, Issue I, January/2019

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Detailed morphometric analysis of a study area is a great help in understanding the influence of drainage

morphometry on land forms and their characteristics. The drainage characteristics of study area were studied to

describe and evaluate their hydrological characteristics by analyzing topographical map and SRTM data.

The fundamental unit of virtually all watershed and fluvial investigations is the drainage basin. An individual

drainage basin (catchment or watershed) is a finite area whose runoff is channeled through a single outlet. In its

simplest form, a drainage basin is an area that funnels all runoff to the mouth of a stream. Drainage basins may

be delineated on a topographic map by tracing their perimeters or drainage divides. A drainage divide is simply

a line on either side of which water flows to different streams. Locally, the most famous drainage divide is the

continental divide. Each drainage basin is entirely enclosed by a drainage divide. Drainage basins are

commonly treated as physical entities. For instance, flood control along a particular river invariably focuses on

the drainage basin of that river alone. Because drainage basins are discrete landforms suitable for statistical,

comparative, and analytical analyses, innumerable means of numerically and qualitatively describing they have

been proposed. Morphometry is essentially quantitative, involving numerical variables whose values may be

recovered from topographic maps. The importance of morphometric variables is their usefulness for

comparisons and statistical analyses.

They study area enjoys semi-arid conditions. The main occupation of the people in this area is agriculture. They

depend on groundwater, because surface water resource is scarce. Due to erratic rainfall pattern and

uncontrolled abstraction, groundwater levels have declined to deeper levels. Therefore watershed development

schemes become important for developing the surface and groundwater resources in these areas. To prepare

comprehensive watershed development plan, it becomes necessary to understand the topography, erosion status

and drainage pattern of the region.

2. Study area

The study area is located in the northern part of Salem district, Tamilnadu,India. It lies between 11036’47” to

11057’10”N latitude and 78002’48” to 78024’50”E longitude. The areal extent of the study area is about 894.58

Sq.Kms. The study area is covered by Harur block in the northern part, Salem block in the southern part and

Omalur block in the western part.The study area lies on the footwall of northern side of the geologically active

tectonic zones of Moyar-Bhavani-Attur (MBA) fault zone. The average maximum temperature of the study area

is about 270C and minimum is about 150C. The study area map is given in Figure 1.

Figure 1 Study area map



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3. Methodology

The morphometric analysis of the study area was prepared based on published topographic maps on 1:50,000

scale and also on SRTM data. The SRTM was an 11 day space shuttle mission February 2000. SRTM has

created an unparalleled data set of global elevations that is freely available for modeling and environmental

applications. The Spatial resolution of data is 90/90 m, or one pixel represents a terrain cell 90/90 m in size. The

SRTM DEM is a fast and inexpensive way for regional geomorphological analysis and understanding terrain

condition. Based on the data we prepared the slope and topography elevation maps with contours for the

watershed stream network and micro watersheds were prepared using ArcGIS 9.3 software.

The drainage network of the study area was scanned and digitized as available on toposheets (1:50,000). The

entire study area has been divided into three sub-watersheds (SBW)namely SBW-I (Vaniyar), SBW-II

(Sarabanga) and SBW-III (Tirumanimuthar) (Figure 2). Based on the drainage order, the drainage channels

were classified into different orders (Strahler, 1952). Basin parameters such as area, perimeter, length, stream

length, stream order also calculated and later used to calculate other parameters like bifurcation ratio, stream

length ratio, coefficient, stream frequency, drainage density, drainage texture, basin relief, relief ratio,

elongation ratio, circularity index, and form factor were evaluated with the help of established mathematical

equation (Strahler, 1964). The morphometric parameters were divided into three categories as linear, areal and

relief aspects of the study area (Figure 3).

Figure 2 Stream orders and sub-watersheds Figure 3 Flowchart for methodology adopted in

Morphometric analysis

4. Morphometric Analysis

Systematic description of the geometry of a drainage basin and its stream channel requires measurement of

linear aspects of the drainage network, areal aspects of the drainage basin, and relief (gradient) aspects of the

channel network and contributing ground slopes. In the present study, the morphometric analysis was carried

out with respect to different parameters. The properties of the stream networks are very important to study the

landform making process.

3.1 Linear Aspects

The linear aspects of morphometric analysis of sub-watershed includestream order (U), stream number (Nu),

stream length (Lu), mean stream length(Lsm), stream length ratio (Rl) and bifurcation ratio (Rb).



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3.1.2 Stream Order

The designation of stream orders is the first step in drainage basinanalysis and expresses the hierarchical

relationship between stream segments,their connectivity and the discharge arousing from contributing

catchments. Inthe present study, the stream ordering has been carried out using Strahler(1952) method. The

order wise stream numbers and length of three subwatershedsare counted and which indicates that SBW-I,

II,and III sub-watersheds have streams up to fifth order. The numbers of streamsegments present in each order

are counted and it is observed that the numberof stream segments decreases as the stream order increases. This

observation isin accordance with the Horton’s Law which states that the number of streamsegments of each

order form an inverse geometric sequence with plottedagainst order, most drainage networks show a linear

relationship, with smalldeviation from a straight line. This law is followed in the study area and thegeometric

relationship is shown graphically in the form of straight line whenthe log value of these variable stream order is

stream numbers and stream orderis stream length are plotted suggesting the area to be in normal basin

(pearshaped basin) category (Figure 4 & 5).

Figure 4 Log plot for Stream order Figure 5 Log plot for stream order

vs. stream number vs. mean stream length

3.1.3 Stream Number (Nu)

The total of order wise stream segments is known as stream number. Nuis number of streams of order u.

Nu = N1+N2+…Nn

Where, N1 = First order stream

N2 = Second order stream

Nn = Number of streams

Stream number (Nu) observed that the number of streams graduallydecreases as the ordering of the streams

increase. This is in accordance with theHorton’s (1945) law which states that the “number of stream segments

of eachorder forms an inverse geometric sequence with order number”. Thedemarcated sub-watersheds of total

study area has first order stream(Nu1=1964), second order stream (Nu2=449), third order stream

(Nu3=103),fourth order stream (Nu4=21) and fifth order stream (Nu5=8). The totalnumber of streams in the

entire drainage network is 2545. The variation in thetotal number and total length of the stream in drainage is

mainly due toprecipitation, morphology and lithology of the terrain. The terrain has been characterized by flat

land, steep slope and hilly area, with medium precipitation. The understanding of streams in a drainage system

constitutes the drainage pattern which in turn replicates mainly structural/ lithologic controls of the underlying

rocks. The study area possesses dendritic, sub-dendritic and radial drainage patterns, despite stream lengths and



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other hydrological properties. They are generally characterized by a treelike branching system which indicates

the homogenous and uniformity.

3.1.4 Stream Length (Lu)

The total length of individual stream segments of each order is the stream length of that order.

Lu = L1+L2 ……Ln

Where, Lu is stream length,

L1 is length of the first order stream,

L2 is length of the second order stream and

Ln is n number of the stream length.

The stream length is computed based on the Horton Law for all the three sub-watersheds. The number of

streams of various order in the sub-watersheds counted and their lengths are measured. In the study area, total

length of stream segments is maximum for first order and decreases as stream order increases.

This is a normal trend and indicates that the terrain is gently sloping, low relief and homogenous lithology.

However, in all three sub-watersheds, the stream segments of various orders, varies considerably which implies

that the subwatershedshave different morphometric attributes.

3.1.5 Mean Stream Length (LSM)

Mean Stream length is a dimensional property revealing the characteristic size of components of a drainage

network and its contributingstudy area surfaces (Strahler, 1964).

�� =��

��

Where, Lu is stream length and Nu is stream number.

The mean stream length is calculated by dividing the total stream length of given order and number of stream of

that order. In the study area, it is noted that Lsm varies from 8 to 0.6 km and its value for any given order is

greater than that of the lower order and less than that of its next higher order in all the sub-watersheds except

sub-watershed SBW-III, which is abnormally increased, possibly due to variation in the slope and topography in

this sub-watershed.

3.1.6 Stream Length Ratio (Rl)

The stream length ratio can be defined as the ratio of the mean stream length of the given order to the mean

stream length of next lower order and has an important relationship with surface flow and discharge (Horton,

1945).

�� =��

�� − 1

Where,

Lur is the stream length ratio

Lu is the stream length of segment of order u

Lu-1 is the stream segment length of the next lower order.



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The stream length ratio can be defined as the ratio of the mean stream length of a given order to the mean

stream length of next lower order and having important relationship with surface flow and discharge. Stream

length ratio between the streams of different order in each sub-watershed of the study area is variable e.g., sub-

watershed-I show an increasing trend in the streamlength ratio from lower order to next higher order which

indicate their mature geomorphic stage whereas, sub-watersheds-II and III show changes in RL from one order

to another which indicate the late youth to mature stage of geomorphic development.

3.1.7 Bifurcation Ratio (Rb) and Mean Rb ratio

The Bifurcation Ratio is the fundamental importance in drainage basin analysis as it is the foremost parameter

to link the hydrological regime of a study are under topological and climatic conditions. It helps to have an idea

about the shape of the study area as well as in deciphering the runoff behavior.

�� =��

�� + 1

The bifurcation ratio is the ratio of the number of the stream segments of given order ‘Nu’ to the number of

streams in the next higher order (Nu+1). Bifurcation ratio is an index of relief and dissection. It is well

demonstrated that bifurcation ratio shows a small range of variation for different regions or for different

environment except where geological control dominates. It has been found that the bifurcation ratio

characteristically ranges between 1.0 and 9.0 for watershed in which geology is reasonably homogeneous and

no structural disturbances. Bifurcation ratio for different sub-watersheds of the study area have been determined

and given in (Table 4.2). The slope of semi log plots of stream order vs. stream number gives the bifurcation

ratio. The irregularities in the bifurcation ratios of the four sub-watersheds are possibly dependent upon the

drainage basin. The lower values of Rb indicate that the sub-watershed has suffered less structural disturbances

and the drainage pattern is not distorted. Furthermore, the low Rb values signify a high drainage density, low

permeability of the terrain and indicate areas with uniform surficial materials where geology is reasonably

homogeneous. The mean bifurcation ratio, which is the average of bifurcation ratios of all orders, varies from

3.98 to 5.34. The highest value of mean bifurcation ratio is found in subwatershed- II suggesting structural

control in the area and low permeability whereas all other basins are geologically homogenous. This also

suggests that the drainage basin morphometry of SBW-II may have been affected by human activities.

3.2 Aerial Aspects

The aerial aspects include area (Au), perimeter (P), drainage, drainage density (Dd), drainage texture (Dt),

elongation ratio (Re), circularity ratio (Rc),form factor (Ff) and length of overland flow. Study area is

hydrologicallyimportant because it directly affects the size of the storm hydrograph and themagnitudes of peak

and mean runoff. It is interesting that the maximum flood discharge per unit area is inversely related to size.

3.2.1 Area (Au) and Perimeter (P)

The area and perimeter of the study area has been measured using ArcGIS 9.3 by performing clean and build

option i.e., closed polygon, and the values are expressed in Km2. Area and perimeter depend on the number of

segments, length of the segments and attitude. If the parameter is high, then the values of area are also high. The

perimeter of the study area is 161.75 km. Low perimeter is indicated in the gneissic and few parts at charnockite

terrain are almost flat to undulating topography. The computed total areal coverage of the study area is 894.58

sq. km.



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3.2.2 Drainage

Drainage patterns are the disposition and preferred occurrence of streams on the surface of land. A drainage

pattern can be defined as the design formed by the aggregate of drainage ways in an area regardless of whether

they are occupied by permanent or temporary streams (Howard, 1967). Initial slope, lithology and

meteorological parameters (precipitation in the form of rainfall) is distinctly assertive in the generation of a

drainage pattern. The study area has varied drainage patterns viz., dendritic, sub-dendritic and radial types.

3.2.3 Drainage Density (Dd)

The drainage density determines the time travel by water (Schumm, 1956). The measurement of density is a

useful numerical measure of landscape dissection and runoff potential (Chorley et al 1957). A high drainage

density reflects a highly dissected drainage basin with a relatively rapid hydrological response to rainfall events,

while a low drainage density means a poorly drained basin with a slow hydrologic response (Melton, 1957).

Drainage density is the result of interacting factors controlling the surface runoff and in turn influences the

output of water and sediment from the drainage basin. Drainage density is known for variation in climate and

vegetation, soil and rock properties, relief and landscape evolution processes. In general, the hydrology of study

area changes significantly in response to the changes in the drainage density. The drainage density is the length

of streams per unit area as defined by Horton, 1945. The drainage density indicates the closeness of spacing of

channels (Horton, 1932).

�� = �� / �

Where, Lu is the total length of stream

A is the area of the study in sq. km.

A low drainage density indicates permeable subsurface strata and has a characteristic feature of coarse drainage

which generally shows values less than 5.0. Strahler (1964) noted that low drainage density is favored where

basin relief is low and vice versa. The drainage density of the SBW-I is 0.875 km/km2, SBW-II is 0.552

km/km2 SBW-III is 0.822 km/km2 and total study area is 2.24 km/km2, which indicates that the study area has

a weak or permeable subsurface material with intermediate drainage and low relief. The drainage density of the

study area is shown in (Figure 6).

Figure 6 Drainage density



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3.2.4 Drainage Texture (Dt)

Drainage texture (Dt) is one of the important concept of geomorphology which means that the relative spacing

of drainage lines.

Dt = Nu / P

Drainage texture (Dt) is total number of stream segments of all orders per perimeter of that area (Horton, 1945).

Smith (1950) classified drainage densityinto five classes i.e. Very coarse (<2), Coarse (2-4), Moderate (4-6),

Fine (6-8) and Very fine (>8). Low density represents coarse drainage texture; while high drainage density

represents fine drainage texture. In the present case, the drainage texture of the SBW-I is 6.49, SBW-II is 4.08

SBW-III is 5.14 and total study area is 15.78 indicates that the category is very fine drainage texture and

impermeable lithology. Drainage lines are numerous over impermeable areas than permeable areas and it is the

measure of the total number of segments of all order per perimeter of that area. It gives an idea of the infiltration

rate of the study area.

3.2.5 Elongation Ratio (Re)

Elongation ratio is the ratio between the diameter of a circle of the area as the drainage basin and the maximum

length of the same basin (Schumm, 1956). A circular area is more efficient in runoff discharge than elongated

site (Singh and Singh, 1997).

�� =2

��∗ �

�

�� 0.5

Where, Lb is the length of the study area A is study area in sq. km According to Strahler (1952) the elongation

ratio between 0.6 and 0.8 indicates high relief and steep slope region. The elongation ratio of the study area is

0.003 and it indicates more elongated and steep slope.

3.2.6 Circularity Ratio (Rc)

The ratio of the circle has the same circumference as the perimeter of the circulatory ratio. It is also influenced

by the length and frequency of stream, geological structures, land use / land cover, climate, relief and slope of

the drainage network and is expressed as:

�� = 12.57 ∗�

�2

Where, Rc = Drainage circulatory

A= Area of the drainage network

P=Perimeter of the drainage network

The study area drainage circularity value is calculated as 0.43, it indicates that moderate to high relief and the

drainage system are structurally controlled.

3.2.7 Form Factor (Ff)

The form factor (Ff) is the ratio of study area to the square of the basin length and is a quantitative expression of

drainage area outline. It indicates the flow intensity of study area a defined area (Horton, 1945).



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�� =�

�2

Where, Lb is the study area length (km) and A is the area of the study area (km2) The form factor (Ff) value

varies from 0 in highly elongated basin to 1 for a perfectly circular basin. The Ff value of the whole watershed

is 0.53. The value of form factor suggests that the study watershed is slightly elongated in shape. The study area

with high form factors have high peak flows of shorter duration, whereas elongated study area with low form

factor 0.53 indicating them to be slightly elongated in shape and lower peak flows for longer duration. Flood

flows of elongated watershed are easier to manage than that of the circular watershed (Nautiyal, 1994).

3.2.8 Length of Overland Flow (Lg)

The length of overland flow is the length of water over the ground surface before it gets concentrated into

definite stream channel (Horton, 1945).

�� =�

2∗ ��

‘Lg’ is one of the most important independent variables affecting hydrologic and physiographic development of

drainage basin. The length of overland flow is approximately equal to the half of the reciprocal of drainage

density (Horton,1945). This factor is related inversely to the average slope of the channel and is quite

synonymous with the length of sheet flow to a large degree. The computed ‘Lg’ value of the study area is 0.23.

It indicates that the channel erosion is dominant than sheet erosion.

3.3 Relief Aspects

Linear and areal features have been considered as the two dimensional aspect lie on a plan. The third dimension

introduces the concept of relief. By measuring the vertical fall from the head of each stream segment to the

point where it joins the higher order stream and dividing the total by the number of streams of that order, it is

possible to obtain the average vertical fall. The relief aspects determined include altitude (At), slope (Sl), aspect

(As), relative relief and ruggedness number.

Digital elevation models (DEMs) is a digital representation of the topographical surface. It is used for visual

interpretation, analysis of topography, landforms, providing flood and landslide risk zone, as well as modeling

of surface processes. In the present study, GIS is being used in various purposes such as evaluation of surface

features for geomorphological studies. DEM map is representing the altitude of the study area ranging from

Zero to 1400 amsl. Aspect, slope, elevation and shaded relief maps which are generated in Arc GIS 9.3 software

from the DEM input data to know the topographical slope direction and geological features of the area.

3.3.1 Altitude (At)

The relative height (Strahler, 1952) is difference between the minimum height and maximum height of the

particular area is defined as

�ℎ =ℎ

�



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The computed relative height of the study area is 0.14m. Total area relief is the maximum vertical distance

between the lowest and the highest points in a basin (Horton, 1945; Strahler, 1964).

H = Z – z (4.13)

Study are a relief is an important factor in understanding the denudational characteristics of the area. The

maximum height of the whole watershed is 1635 m amsl and the lowest is 264m amsl. Therefore, the total relief

of the study area is 1371m amsl(Figure 7).

Figure 7 SRTM DEM and altitude

3.3.2 Slope (Sl)

The slope is an important analysis feature of a watershed. It relates to the speed of the runoff, thereby affecting

the time required for rain water to concentration the river beds that make up the network of the drainage basin

(Villela and Mattos, 1975).An understanding of slope distribution is essential for planning, settlement,

mechanization of agriculture, deforestation, planning of engineering structures and conservation practices etc.

(Sreedevi et al 2005). In the present study, slope map was prepared from SRTM data using GIS Arcview

method (ESRI, 2000). In study area slope vary from 0° to 51° (Figure8). A high degree of slope is noticed in the

western and northwestern parts of the area. The study area slope measures the overall steepness of a drainage

basin and is an indicator of the intensity of erosion process operating on slope of the basin (Schumm, 1956).

The height (H) and length (Lb) of the basin were considered.

�� =�

��

The computed value of ‘Sw’ in the study area are 0.0328 indicating gentle slope.



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Figure 8 Slope angle

3.3.3 Average Slope (S)

The erodibility of a study areacan be studied and compared from itsaverage slope (Wenthworth, 1930). More

percentage of slopes accelerates erosion, if all other parameters are kept constant. The average slope of the

subbasin is determined as,

� = (� ∗ ��)/(10 ∗ �)

Where, S is the average slope, Z is maximum height of the basin, Ctl is total contour length and A is area of the

basin. The computed the average slope of the study area is 1.89%.We identified that 35% of the basin

dominates the lower slopes, with between 0% - 6% of the basin being associated with reliefs and exhibiting

practically plane and soft wavy shapes; this area is located between the sources of its tributaries and the mouth

of the study area. The slopes steeper than 30% comprise 0.4% of the area and occur in the west, in areas where

the relief has strong waveforms that are characterized by the presence of hillocks and hills (Figure 9).

Figure 9 Slope percentage

3.3.4 Aspect

An aspect-slope map simultaneously shows the aspect (direction) and degree (steepness) of slope for a terrain.

The aspect of slope has a very significant influence on the local climate and distribution of vegetation and



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biodiversity of any area (Magesh et al 2012). (Figure 10) shows the color coded map of the study area

representing the compass direction of the aspect, 0 is true north; a 90 aspect is to the east, and so forth. Thus the

southeast, south and southwest slopes are dominant in the study area. As a result, these slopes have a high

evaporation rate and are drier supporting poor vegetation cover.

Figure 10 Slope aspect

3.3.5 Relative Relief (Rhp)

Relative relief is to ascertain the amplitude of available relief to relate the altitude of the highest and the lowest

points of any particular area (Smith, 1935).

RR = Maximum elevation (M) – Minimum elevation (m)

It means that the difference between the highest and the lowest point in a spatial unit and plays an important

role to understand the morphological characteristics of terrain, degree of dissection and

denudationalcharacteristics of the watershed, which together control the stream gradient, thereby influencing the

flood pattern (Hadley and Schumm, 1961).The relative relief of different sub-watersheds have been determined

and and was used by Melton. It is noted that sub-watershed-II has (1.30) maximum value of relative relief and

sub-watershed-I has the (0.98) minimum value. Furthermore, visual study of the SRTM DEM indicates that the

elevation varies which represent the land surface has gentle to moderate slope.

3.3.6 Ruggedness Number (Hd)

Ruggedness number indicates the structural complexity of the terrain. An extreme high value of ruggedness

number occurs when both variables i.e. drainage density and relief are high and slope is not only steep but long

as well (Strahler, 1956).

�� =��

�∗ 1000

It is the product of maximum basin relief (H) and drainage density (D), where both parameters are in the same

unit. An extreme high value of ruggedness number occurs when both variables are large and slope is not only

steep but long as well. In the present study, the value of ruggedness number is low which indicates gentle slope

of all the sub-watersheds.



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5. Result and Discussion

Morphometric parameters are evaluated in the study area and the overall stream length of 2012 km indicate

flowing of streams from high altitude, lithological variation and moderately steep slopes. The terrain

characterized by flat land, steep slope and hilly area, with medium precipitation. The stream length ratio

between the pair L1/L2 is significantly higher stream frequency; it indicates a greater surface runoff and steeper

gradient. In general, bifurcation ratio (Rb) value within the ranges of 3-5 is an accepted value for natural fluvial

system. Low perimeter is indicated in the gneissic and few parts at charnockite terrain is almost flat to

undulating topography and the maximum drainage texture of the study area is 15.78 and it indicates that the

category is very fine drainage texture and impermeable lithology. According to Strahler (1952) the elongation

ratio between 0.6 and 0.8 indicates high relief and steep slope region. The study area has a value of circularity

ratio (Rc) 0.43 which prioritation indicates moderate to high relief and the drainage systems are structurally

controlled. The computed length of overland flow ‘Lg’ value of the study area is 0.23; it indicates that the

channel erosion is dominant than the sheet erosion. The value of maximum relative relief in the study area is

1.30 indicating moderate relief and gentle slope. The low ruggedness value of block implies that the area is less

prone to soil erosion and has an intrinsic structural complexity in association with relief and drainage density.

4.1 Artificial Recharge structures using Morphometric parameters

GIS is an efficient tool to integrate different layers and to determine inter-relationship amongst the various

themes in water resource development plan. Different thematic layers are brought to a common coordinate

system so that integration is possible and accuracy of the output is maintained. For all three sub-watersheds, the

drainage and land use / land cover maps are superimposed to site selection and construction of artificial

recharge structures within the study area (Figure 11 to 13). Based on the stream ordering and land use patterns

the all three sub-watershed categorized under different artificial recharge structures such as percolation tank,

nalla bund and check dams are proposed in the study area .Check dams, nalla bunds/plugs and percolation point

provide a good measure of recharge structures in the hard rock terrains by arresting runoff and increasing the

surface area of infiltration. Suitability of these structures depends on various factors, which can be integrated by

GIS techniques (Kumar et al. 2008).

Figure 11 Artificial recharge structures based Figure 12 Artificial recharge structures based on morphological parameters in Sub-watershed I on morphological parameters in Sub-watershed II



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Figure 13 Artificial recharge structures based on morphological parameters in Sub-watershed III

Thenalla bunds are low cost small bunds across 1st to 3rd lower order streams. They are suitable at the upper

reaches where catchments are small and stream courses have been deepened by erosion. They may be made of

dry stone masonry or boulders or even by brushwood. It is better to have a series of small height bunds. Since

the essential function is to stabilize the gully and improve its grade by checking erosion; it is generally

recommended that the foot of an upstream gully plug be at the level of the successive downstream bund.Check

dams are engineered structures constructed across higher order (>3rd order) streams having a minimum average

area of 25 ha. These structures are proposed or constructed for checking the stream runoff during monsoon and

for the purpose of storage of water are these may also help recharge of groundwater reservoir located in the near

vicinity. The percolation pond structures built near 3rd to 4th order stream to impound surface run off coming

from the catchments and to facilitate percolation of stored water in to the soil substrata with a view to raise

groundwater level. The minimum size of the site is kept up to 40 ha. While proposing the site for percolation, it

is kept in consideration that the area is not presently undergoing agriculture practices. Wasteland having

adequate fractures to facilitate good groundwater recharge is quite suitable for construction of percolation tanks.

6. Summary and Conclusion

The quantitative morphometric analysis of the study area has provided the hydrological behavior, basin

evolutionary history and maturity of the terrain. The SOI topographic map and GIS technique were utilized for

analysis of various morphometric parameters in the study area, which include linear, aerial and relief aspects

and different parameters. The different quantitative morphometric parameters and their influences in sediment

water peak discharge, structural distrubance and geological process. were estimated and analyzed. The

morphometric analyses provided valuable informations. The bifurcation ratio indicates that the study area is not

affected by any major structural disturbances. The form factor has indicated that the basin is slightly elongated

with flatter peak flow and longer duration.

7. References

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pp.161–188.

2. Agarwal. CS (1998). Study of drainage pattern through aerial data in Naugarh area of Varanasi district, U.P.

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3.Alaguraja, P., Manivel, M., Nagarathinam, S. R., Sakthivel, R. and Yuvaraj, D. (2010) Rainfall Distribution

Study in Coimbatore District Using Geographic Information System (GIS), Book: Recent Trends in Water

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Basin, Himachal Pradesh, India, J Geogr Nat Disast 2016, 6:2

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155-156.

6. Horton. R.E.(1932).Drainage Basin Characteristics. Transfixions of Am. Geophysics. Union, 13:350

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quantitative morphology. Geological Society of American Bulletin. 56:pp. 275-370.

7.Howard. AD (1967). Drainage analysis in geologic interpretation: A summation, Bulletin of American

Association of Petroleum Geology, 21, 2246- 2259.http://srtm.usgs.gov/data/

8.Jayakumar P D, Govindaraju, and LingadevaruD C., (2003), Prioritisation of Subwatersheds in the catchment

of upper Tunga reservoir based on Morphometric and land use analysis using remote sensing and GIS

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9. Kandasamy V (1986), Hydrological study of Watersheds in Nilgiris district, Institute of Remote Sensig, Anna

University, Chennai.

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