PRIORITIZATION OF MICRO- WATERSHEDS - Shodhgangashodhganga.inflibnet.ac.in/bitstream/10603/27945/13/13_chapter7.pdf · Chapter 7 : Prioritization of Micro-Watersheds 175 7.1 INTRODUCTION

Chapter 7 : Prioritization of Micro-Watersheds

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7.1 INTRODUCTION

Optimal management of natural resources on sustainable basis is of utmost

importance in today’s context. Sustainable increase in production of food grains,

fiber, fodder, etc. is a most to meet the need of increasing population. The

planners face a problem of striking a balance between two competing demands of

development and conservation of natural resources. Therefore, management needs

to address different dimensions related to physical condition of resource,

environmental aspects, economic viability, social acceptability etc. If plans are to

incorporate all parameters discussed above, a holistic approach needs to be

adopted. To generate integrated plans for an area development/management, one

requires information on individual elements as well as the inter-relationships

among different elements of the terrain. This could be achieved if the thematic

maps on land use/ land cover, soil, slope, water resources etc. are seen in an

integrated fashion. One of the difficulties faced by planners relates to the

availability of information on different resources and their accuracies, recentness

of the data, compatibility of different data sets in terms of information details,

scale, format etc, temporal changes with respect to utilization, degradation etc. in

a spatial context. In addition, planners also require a reliable mechanism to assess

the success of the implementation of various schemes. Inputs from science and

technology play a vital role in providing necessary data and in analyzing these

data sets to arrive at optimum solutions.

The growing pressures on land for food, fiber and fodder in addition to industrial

expansion and consequent need for infrastructure facilities due to even increasing

population have given rise to competing and conflicting demands on finite land

and water resources. About 175 Mha of land in India, Constituting about 53 per

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cent of her total geographical area, suffer from deleterious effect of soil erosion

and other forms of land degradation. A country like India that supports 16 per cent

of world population on 2 per cent of the global land area, the problem is serious

enough. Keeping in view of the ever increasing population and need for food

security for the future generation, it is realized that the water and land resources

need to be developed, used and managed in an integrated and comprehensive

manner. It has already been realized that the soil and water conservation measures

carried out on a watershed basin play a prominent role in this strategy of

comprehensive land and water management.

A watershed is an area from which runoff resulting from precipitation flows past a

single point into large stream, river, lake or ocean. Thus, a watershed is the

surface area drained by a part or the totality of one or several given water courses

and can be taken as a basic erosional landscape element where land and water

resources interact in a perceptible manner. Watershed management is the process

of formulation and carrying out a course of action involving modification of the

natural system of watershed to achieve specified objectives. It implies the proper

use of land and water resources of a watershed for optimum production with

minimum hazard to natural resources. Remote Sensing and GIS techniques have

emerged as powerful tools for watershed management programmers.

A watershed is a natural and complete topographical and hydrological entity that

collects and converge all the rainwater falling on it to a common outlet. Therefore

a watershed is an ideal unit for management and sustainable development of its

resources. The basic natural resources of watershed include water, land and

vegetation.

Rapid increase in population, urbanization, expansive and intensive agriculture,

large construction, etc., have resulted in ever increasing demands on land and

water, and caused enormous degradation of environment and forest, loss of

productive soils, depletion and pollution of surface and sub-surface water

resources, and sedimentation of rivers and reservoirs. Therefore the existing


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condition for conservation and improvement of soil is surface and subsurface

water resources and most importantly the forest resources.

Vegetation cover is the most important and most of the environmental degradation

and its harmful effects faced today are mainly due to the degradation of vegetation

cover. Afforestation that is improvement of the vegetative cover naturally

improves the soil conditions, helps in its effective conservation, leads to

improvement in surface and subsurface water resources reducing the adverse

effects such as draught, improving agriculture, and in turn improving the

vegetation and environmental conditions. Topography, the surface configuration

of the terrain is another important attribute in the hydrological processes in a

watershed. Slope of terrain is one attribute of topography that can have very

adverse effect on both soil and water resources as well as on land use development

in a watershed.

The effects of slope, land use that is mainly vegetation cover and soil properties

on the hydrological processes especially soil erosion of a watershed are well

summarized in the literature. As can be seen, amongst the three attributes, viz.

topography, land use and soils topography has the greatest influence. As the slope

steepness increases, runoff velocity and volume increases, with it the kinetic

energy and carrying capacity of the surface flow increase, infiltration decreases,

soil slope stability decreases and the soil displacement down the slope increases.

Vegetation cover protects the soil against the impact and energy of the falling

raindrops and dissipates it. It reduces the velocity, kinetic energy and the volumes

of runoff and increases the infiltration capacities of the soils, thus reducing the soil

erosion. This consequently improves the physical, chemical and biological

properties of the soil.

The deterioration of natural resources is as old as the first man who cut the first

tree to practice arable farming. In India’s post-independence period, the increase

in agriculture using excessive irrigation, over-application of fertilizers and

bringing more area under cultivation has led to serious erosion hazards, water

logging, changing water courses, soil erosion, and deforestation in large areas, soil


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salinity and alkalinity. To compound the problems further, recurrent natural

disasters like drought and floods put constraint to natural resources development.

The population explosion coupled with urbanization, industrialization and the

resultant decrease in arable land available for agriculture have put tremendous

pressure on the land and water resources. In India, 75% of the total cropped area is

un-irrigated and it accounts for 42% of the total crop production. The rainfall in

these areas exhibits wide variations in time and space, introducing an element of

risk, uncertainty and instability in crop production. This is primarily due to the

monsoon nature of rainfall and its inadequacy to meet the demands, in the semi-

arid tropics; the rains are of high intensity and, together with lack of organic

matter like the black soils of India. This results in excess runoff, poor moisture

intake and loss of precious topsoil due to water erosion. This is, further aggravated

by high prevailing temperatures leading to greater evaporation losses. Hence,

accurate and timely mapping, monitoring and assessment of conditions in the

watershed area are essential for assessing land and water resources and their

optimum utilization for sustainable development.

In dry land agricultural areas productivity is lower due to inadequate moisture

availability at crucial stages of crop growth. Soil and water conservation measures

have been long practiced to protect the productive lands. These measures are

suggested based on terrain characteristics like land use, soils slope, hydro-

geomorphology, etc. Remote Sensing and GIS techniques have been used recently

to arrive at cost-effective plans for conservation and development measures for

watersheds.

Several scientist have worked using Remote Sensing, GIS Techniques and

different erosion estimation models, prioritize the watersheds and to find

appropriate location for check dam construction in different areas of entire

watershed. Prioritization of watersheds using remote sensing data by sediment

yield prediction has been carried out by Chakraborti (1991). Site location for

check dam construction by studying runoff in part of Mahi River has been carried

out by Durbude et al. (2001). GIS overlaying techniques has been used to locate

the potential zones of ground water (Murthy, 2000). Chinnamani (1991)


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estimated sediment yield using remote sensing data. Mani et al (2003) carried out

soil erosion studies of part of the world’s largest river island, Majuli River- Island,

using remote Sensing data and ILWIS software.

7.2 REVIEW OF LITERATURE

R.E. Horton and A. E. Strahler (1940s and 1950s) - First initiated

Morphometric studies in the field of hydrology in the 1940s and 1950s.

Determining geomorphic parameters in the past has been a tedious and time

consuming process due to the efforts needed in delineation of watersheds and

calculating the respective watershed areas.

Nautiyal (1994) - Research provides morphometric analysis by focusing on the

analysis of the drainage basin using aerial photographs. Paper evaluates the real

life case study of Khairkuli basin, District Dehradun, India using morphometric

analysis using aerial photographs.

Sujata Biswas, S.Sudhakar and V.R.Desai (1999) have reported on

“Prioritization of Sub watersheds based on Morphometric Analysis of Drainage

Basin; A Remote Sensing and GIS Approach.” They aimed for prioritization of

sub watersheds enveloping the Nayagam Block, Midnapore District, West Bengal

for soil erosion purpose. They divided the study area in 9 sub watershed. They

used Remote sensing data like FCC of IRS-1C LISS III satellite data, SOI

Toposheeet of 1:50,000 scale and GIS for morphometric analysis. They prioritized

all the sub watersheds and provided a ranking to each sub watershed. All the sub

watersheds were prioritized and ranking to each sub watershed was given based

on soil erosion.

Khan (2001) considered an integral part of the Guhiya basin with a total area of

1614 km2 for his study. Considered an integral part of the Guhiya basin with a

total area of 1614 km2 for his study. The basin contains numerous rivers (the

Guhiya, the Radiya, the Modiya, the Guriya and the Lilri), which finally drain into

Sardar Samand reservoir, located to the southeast of the Jodhpur district of

western Rajasthan, India. Morphologically, geo-morphologically and hydro


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logically the basin had good variations. The priority watershed concept study was

made involving (1) appraisal of natural resources such as landform, storage,

drainage morphometric, and present land-use/ land-cover using topographical

sheets at 1:50,000 scale, satellite data at 1:250,000 and 1:50,000 scale and field

survey and their thematic mapping; (2) delineation of watersheds using same data

source; (3) mapping and assessment of erosion intensity units (EIU) using

Geographical Information System (GIS) procedures, and (4) estimation of

sediment yield index (SYI).

Gopalkrishna (2004) investigated the Hemavathi and Yagachi tributaries to river

Cauvery, India. The drainage system was dendritic to sub-dendritic and the

geomorphology of the area controls the geometric configuration of the aquifer

media. Major structural features observed in the area were Hemavathi-Thirthahalli

mega lineament. The other lineaments were parallel to mega lineament and these

controlled the streams and their flow directions. Hemavathi and Yagachi were

found to be perennial; whereas the remaining streams are seasonal.

Gwod (2004) carried out morphometric analysis and their relative parameters

were quantified for the Peddavanka basin, Anantapur district, Andhra Pradesh,

India. The quantitative analysis of the morphometric characteristics of the basin

included stream order, stream length, bifurcation ratio, drainage density, drainage

frequency, relief ratio, elongation ratio and circularity ratio. The foregoing

analysis clearly indicated by Gwod (2004) for some relations among the various

attributes of the morphometric aspects of the basin and helps to understand their

role in sculpturing the surface of the region.

K.Nookaratnam, Y.K.Srivastava, V.Venkateswararao, E.Amminedu and

K.S.R.Murthy (2005) from Andhra University have already suggested the

methodology of “Check Dam Positioning By Prioritization Of Micro-Watersheds

Using SYI Model And Morphometric Analysis – Remote Sensing And GIS

Prespective.” They prioritized proper sites for check dam construction based on

micro-watershed prioritization using remote sensing data. They have used various

types of remote sensing & GIS data, SOI Topo sheets and NBSS & LUP maps


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which are the basic requirements for carrying out the morphometric analysis and

for estimation of soil erosion. Various thematic maps like LU/LC map, Soil map,

Watershed map, Slope map, Soil erosion map were generated by Arc GIS-9.0

version, which were used in computation of morphometric parameters such as a

bifurcation ratio, drainage density, texture ratio, length of the overland flow,

stream frequency, compactness coefficient, circularity ratio, elongation ratio,

shape factor and form factor. Automated demarcation of prioritization of micro-

watersheds was done by using GIS overlaying technique by assigning weight

factors to all the identified features in each thematic map and ranks were assigned

to the morphometric parameters. Five categories of priority viz. very high, high,

medium, low and very low were given to all the watersheds in both morphometric

analysis and SYI methods. Sixty-two micro-watersheds using SYI method and

twenty-three micro watersheds using morphometric have been prioritized for high

priority. Final priority map had been prepared by considering the commonly

occurring very high prioritized micro watersheds in both SYI and morphometric

analysis. The ranking of micro-watershed directly indicated the soil erosion of

particular micro-watershed under study area.

Nooka Ratnam (2005) aimed for the identification of the proper sites for check

dams construction, based on micro-watershed prioritization by using remote

sensing data, like IRS LISS-III digital data. SOI toposheets of 1:50,000 scales and

other reference maps. With the use of these remotely sensed data and GIS

technique as well as morphometric analysis various thematic maps such as a land

use/land cover, slope drainage, soil had prepared. Morphometric parameters such

as a bifurcation ratio, drainage density, texture ratio, length of the overland flow,

stream frequency, compactness coefficient, circularity ratio, elongation ratio,

shape factor and form factor were computed. Automated demarcation of

prioritization of micro-watersheds was done by using GIS overlaying technique by

assigning weight factors to all the identified features in each thematic map and

ranks were assigned to the morphometric parameters. Five categories of priority

viz. very high, high, medium, low and very low were given to all the watersheds

in both morphometric analysis and SYI methods. Sixty-two micro-watersheds

using SYI method and twenty-three micro watersheds using morphometric have


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been prioritized as very high priority. Final priority map has been prepared by

considering the commonly occurred very high prioritized micro watersheds in

both SYI and morphometric analysis.

Prasad (2006) had worked on the study area of Valagalamanda River rises from

the Valikonda hills and flows eastwards for about 25 KM and joins Swarnamukhi

River at Cheemuru Village. The drainage pattern was dendritic. Quantitative

analysis aspect means morphometric analysis was used for a given drainage

pattern. It was a 6th order basin and elongated in East-West direction. The

bifurcation ratio was 3.8 and hypsometric analysis indicated the mature stage of

development. The stream length ratio was 0.87, area ratio was 4.04, mean

drainage density was 2.41 Km/Sq.Km and stream frequency of the basin was 2.78

per Sq.Km. The general slope of the basin was from West to East. The low slope

regions are potential zones for ground water accumulation.

Jain (2006) selected a study area of Danda Watershed, located in Hindolakhal,

Block of Utterpradesh. The area falls in Survey of India (SOI) Toposheet No. 53

J/12. Details, such as, roads, streams, settlements and spot height, contours etc.

were taken from this toposheet. The Danda watershed had an area of 450.44 ha at

the gauging site (under construction) near Dugyar village. Drainage information

for this map was derived from SOI toposheet and IRS-1C PAN data. In this

watershed, various streams forming a dendritic pattern were presented. The

mapping of drainage pattern was carried out using satellite data. Computation of

the parameters required for morphometric analysis using manual methods like

area measurement using dot grid method or using planimeter and length

measurement using curvimeter were found tedious and time consuming. It is more

difficult if the map is on higher scale like 1:50,000 and 1:25,000. The ordering,

lengths, area and perimeter etc. can be easily estimated using GIS technique. For

quantification of various geomorphological parameters of Danda watershed, the

digitized drainage and interpolated contours maps were used. A database chiefly

derived from remote sensing, on natural resources such as present land use, land

capability, slope, soils, hydro geomorphology were organized in different layers

using Integrated Land and Water Information System (ILWIS) software. An

integrated layer of Composite Land Development Units (CLDU) was created by


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intersecting the resources layers. Sets of decision rules were applied on CLUDs, to

generate action plan map, showing location specific recommendations in the

watershed.

Schmidt et al. (2006) used several computer techniques and models to investigate

the effects of geomorphometry on rainfall-runoff processes at different scales. The

sensitivity of dynamic hydrologic processes to comparatively static boundary

conditions requires different methods for modeling, analysis and visualisation of

different kinds of data. Therefore an approach integrating several

geocomputational concepts, including spatial analysis of different types of geo-

data, static modeling of spatial structures, dynamic 4D-modelling of hydrologic

processes and statistical techniques was chosen. Geomorphometric analysis of the

research areas was carried out with GIS packages (including ARC/INFO and

GRASS), special purpose software and self-developed tools. Soil-morphometric

relationships were modeled within a GIS environment. Hydrologic models (SAKE

and TOPMODEL) were used to simulate rainfall runoff processes. Statistical tools

and sensitivity analysis were applied to gain an insight into the hydrologic

significance of geomorphometric properties.

Price and Leigh (2006) studied the influence of forest conversion on streams of

the southern Blue Ridge Mountains. Two pairs of lightly impacted

(> 90percentage forest) and moderately impacted (70–80 percentage forest) sub-

basins of the upper Little Tennessee River, USA; were identified for comparison.

Reach characteristics (e.g., slope, drainage area, and riparian cover) were aligned

in each pair to isolate contrasting forest cover as the primary driver of any

detected differences in morphology and sedimentology. A suite of standard cross-

sectional and longitudinal data was collected for each reach for characterization of

the sedimentology and morphology of the streams. Difference of means tests was

conducted to identify parameters significantly differing between the lightly and

moderately impacted streams in both pairs.

Amee K. Thakkar, S. D. Dhiman (2007) studied morphometric analysis and

prioritization of mini watersheds in Mohar watershed, Gujarat state, India using

remote sensing and GIS techniques. In this study, morphometric analysis and

prioritization of the eight mini watersheds of Mohr watershed, located between


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Bayad taluka of Sabarkantha district and Kapadwanj taluka of Kheda district in

Gujarat State, India is carried out using Remote Sensing and GIS techniques. The

morphometric parameters considered for analysis are stream length, bifurcation

ratio, drainage density, stream frequency, texture ratio, form factor, circularity

ratio, elongation ratio and compactness ratio. The Mohr watershed has a dendritic

drainage pattern. The highest bifurcation ratio among all the mini watersheds is

9.5 which indicates a strong structural control on the drainage. The maximum

value of circularity ratio is 0.1197 for the mini watershed 5F2B5b3. The mini

watershed 5F2B5a2 has the maximum elongation ratio (0.66). The form factor

values are in range of 0.29 to 0.34 which indicates that the Mohr watershed has

moderately high peak flow for shorter duration. The compound parameter values

are calculated and prioritization rating of eight mini watersheds in Mohr

watershed is carried out.

S. Srinivasa Vittala, S. Govindaiah and H. Honne Gowda (2008) studied the

Prioritization of sub-watersheds for sustainable development and management of

natural resources: An integrated approach using remote sensing, GIS and socio-

economic data. It has been taken up for prioritization based on available natural

resources derived from satellite images and socio economic conditions, including

drainage density, slope, water yield capacity, groundwater prospects, soil,

wasteland, irrigated area, forest cover and data on agricultural labourers, SC/ST

population and rainfall. On the basis of priority and weightage assigned to each

thematic map, the sub-watersheds have been grouped into three categories: high,

medium and low priority.

Akram Javed, Mohd Yousuf Khanday, Rizwan Ahmed, (2009) carried out

prioritization of sub-watersheds based on morphometric and land use analysis

using remote sensing and GIS Techniques. The present study makes an attempt to

prioritize sub-watersheds based on morphometric and land use characteristics

using remote sensing and GIS techniques in Kanera watershed of Guna district,

Madhya Pradesh. Various morphometric parameters, namely linear and shape

have been determined for each sub-watershed and assigned rank on the basis of

value/relationship so as to arrive at a computed value for a final ranking of the

sub-watersheds.


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Sangita Mishra S., Nagarajan R. (2010) had done a case study on Morphometric

analysis and prioritization of sub-watersheds using GIS and Remote Sensing

techniques in Odisha, India. Poor soil cover, sparse vegetation, erratic rainfall and

lack of soil moisture characterize the study area for most part of the year.

Recurring drought coupled with increase in ground water exploitation results in

decline in the ground water level.

Vipul Shinde, K. N. Tiwari and Manjushree Singh (2010) carried out

prioritization of micro watersheds on the basis of soil erosion hazard using remote

sensing and geographic information system. In this study universal soil loss

equation (USLE) interactively with raster-based geographic information system

(GIS) has been applied to calculate potential soil loss at micro watershed level in

the Konar basin of upper Damodar Valley Catchment of India. Micro watershed

priorities have been fixed on the basis of soil erosion risk to implement

management practices in micro watersheds which will reduce soil erosion in

Konar basin.

Dhruvesh P. Patel (2011) used geo-visualization concept for positioning water

harvesting structures in Varekhadi watershed consisting of 26 mini watersheds,

falling in Lower Tapi Basin (LTB), Surat district, Gujarat state. For prioritization

of the mini watersheds, morphometric analysis was utilized by using the linear

parameters such as bifurcation ratio (Rb), drainage density (Dd), stream frequency

(Fu), texture ratio (T), length of overland flow (Lo) and the shape parameter such

as form factor (Rf), shape factor (Bs), elongation ratio (Re), compactness constant

(Cc) and circularity ratio (Rc). The different prioritization ranks were assigned

after evaluation of the compound factor. 3 Dimensional (3D) Elevation Model

(DEM) from Shuttle Radar Topography Mission (SRTM) and DEM from topo

contour were analyzed in Arc Scene 9.1 and the fly tool was utilized for the

Geovisualization of Varekhadi mini watersheds as per the priority ranks.

Combining this with soil map and slope map, the best feasibility of positioning

check dams in mini-watershed no. 1, 5 and 24 has been proposed, after validation

of the sites.

V. B. Rekha, A. V. George and M. Rita (2011) carried out morphometric

analysis and micro-watershed prioritization of Peruvanthanam sub-watershed, the


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Manimala River Basin, Kerala, South India. A critical evaluation and assessment

of morphometric parameters and prioritization of micro-watersheds based on

water holding capacity of Peruvanthanam subwatershed have been achieved

through measurement of linear, aerial and relief aspects of basins by using remote

sensing and GIS techniques, and it necessitates preparation of a detailed drainage

map. For prioritization, 9 micro-watersheds are delineated and parameters such as

Rb, Dd, Fs,T, Lof and C are calculated separately and prioritization has been done

by using the Raster calculator option of Spatial analyst.

Vipul Shinde & Arabinda Sharma & Kamlesh N. Tiwari & Manjushree

Singh (2011) studied Quantitative Determination of Soil Erosion and

Prioritization of Micro-Watersheds Using Remote Sensing and GIS. The present

study focuses application of most widely used Universal Soil Loss Equation

(USLE) to determine soil erosion and prioritization of micro-watersheds of Upper

Damodar Valley Catchment (UDVC) of India. Geographic Information System

(GIS) is applied to prepare various layers of USLE parameters which interactively

estimate soil erosion at micro-watershed level.

Binay Kumar, Uday Kumar (2011) studied micro watershed characterization

and prioritization using Geomatics technology for natural resources management.

A Composite Suitability Index (CSI) has been calculated for each composite unit

by multiplying weightages with rank of each parameter and summing up the

values of all the parameters. Categorization of the CSI is achieved by ranging the

CSI into classes, where each range indicates the amount of limitation acceptable

for each class.

T.A.Kanth and Zahoor ul Hassan (2012) researched on Morphometric analysis

and prioritization of watersheds for soil and water resource management in Wuler

catchment using geo-spatial tools. The quantitative analysis of morphometric

parameters is found to be of immense utility in watershed prioritization for soil

and water conservation and natural resources management at micro level. The

present work is an attempt to carry out a detailed study of linear and shape

morphometric parameters in nineteen watersheds of Wular catchment and their

prioritization for soil and water resource management.


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Santanu Sharma , Trivani Saikia (2012) carried out prioritization of sub-

watersheds in Khanapara–Bornihat Area of Assam–Meghalaya (India) based on

land use and slope analysis using remote sensing and GIS. The present study

makes an attempt to prioritize the sub-watersheds for adopting the conservation

measure. The prioritization is based on land use and slope analysis using Remote

Sensing and GIS techniques in Khanapara–Bornihat area of Assam and

Meghalaya state (India). The study shows the significance changes in land use

pattern especially in settlement and forest lands from 1972 to 2006. Slope map of

the sub-watersheds prepared from the contour values in the toposheets show the

wide variation of slope in the area ranging from 0° to 87°. Based on the

extent/nature of land use/land cover changes over time and land use/land cover—

slope relationship analysis, the sub-watersheds are classified into three categories

as high, medium and low in terms of priority for conservation and management of

natural resources.

Dhurvesh P Patel,Chintan A Gajjar, Prashant K Shrivastav, (2012) carried

out prioritization of mini-watersheds by morphometric analysis using the linear

parameters such as bifurcation ratio, drainage density, stream frequency, texture

ratio, and length of overland flow and shape parameters such as form factor, shape

factor, elongation ratio, compactness constant, and circularity ratio. The different

prioritization ranks are assigned after evaluation of the compound factor. Digital

elevation model from Shuttle Radar Topography Mission, digitized contour and

other thematic layers like drainage order, drainage density, and geology are

created and analyzed over ArcGIS 9.1 platform. Combining all thematic layers

with soil and slope map, the best feasibility of positioning check dams in mini-

watershed has been proposed, after validating the sites through the field surveys.

Ajoy Das, Milan Mondal, Bhaskar Das, Asim Ratan Ghosh (2012) - A case

study had been done by Analysis of drainage morphometry and watershed

prioritization in Bandu Watershed, Purulia, West Bengal through Remote Sensing

and GIS technology. Due to heavy runoff the main problem of this area is scarcity

of water as well as soil erosion. It has been accepted that for sustainable rural

livelihood water and soil conservation is a must. The most suitable way to achieve

this is micro-watershed development. But there is an acute shortage of


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technical manpower to handle such a huge volume of survey related work.

For that reason, application of Remote Sensing and GIS has become a

necessity. Moreover since fund is limited, watershed prioritization is highly

required.

Sridhar. P, Chandra Bose. A.S, Giridhar. M.V.S.S, Viswanadh. G.K (2012) -

Analysed the Prioritization of mini watersheds based on Morphometric analysis

using GIS . The highest Bifurcation ratio is found to be 11.95 for 4E3C5a. The

Maximum values of Circularity ratio of 0.642 and Drainage density of 3.510 have

been found in Lothuvara mini watershed. The Maximum values of Stream

frequency of 7.25 and Texture ratio of 15.81 have been found in Dorlavagu mini-

watershed. Ranks have been assigned to each parameter based on their value with

highest value as I rank and the rank values of all parameters have been cumulated

to obtain compound parameter. Priorities are arrived at based on compound

parameter values. The mini-watershed with the lowest compound parameter value

is given the highest priority and vice versa.

Hasan Raja Naqvi, Laishram Mirana Devi, Masood Ahsan Siddiqui (2012) -

Soil Loss Prediction and Prioritization Based on Revised Universal Soil Loss

Estimation (RUSLE) Model Using Geospatial Technique had been done. The

present study aims to identify the soil loss estimation, to prioritize the micro

watersheds on the basis of mean soil loss values and to suggest best conservation

measures for the Nun Nadi watershed employing Revised Universal Soil Loss

Estimation (RUSLE) model. This micro level study provides accurate results in

the context of soil loss prediction.

Swati Uniyal and Peeyush Gupta, (2013) analysed the Prioritization based on

Morphometric Analysis of Bhilangana Watershed using Spatial technology.

Various morphometric parameters, namely linear and shape have been determined

for each micro-watersheds and assigned ranks on the basis of value/relationship so

as to arrive at a compound value for a final ranking of the watershed. For the

study stream network along with their order was extracted from ASTER DEM 30

m in geospatial environment. Based on morphometric analysis, the watershed has

been classified into three categories as high medium and low in terms of priority

for conservation and management of natural resources.


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7.3 SCOPE AND OBJECTIVE OF THE PRESENT STUDY

A watershed is the surface area drained by a part or the totality of one or several

given water courses and can be taken as a basic erosional landscape element

where land and water resources interact in a perceptible manner (Swati Uniyal

and Peeyush Gupta, 2013). In fact, they are the fundamental units of the fluvial

landscape. A watershed is an ideal unit for management of natural resources like

land and water and for mitigation of the impact of natural disasters for achieving

sustainable development (T.A. Kanth and Zahoor ul Hassan, 2012). Watershed

is an ideal unit for management and sustainable development of natural resources

(Patel et al, 2012). It is a natural hydrological entity which allows surface runoff

to a defined channel, drain, stream or river at a particular point (Chopra et al,

2005). Watershed management is the process of formulation carrying out a course

of action that involves modification in the natural system of watershed to achieve

specified objectives (Johnson et. al. 2002). It further implies appropriate use of

land and water resources of a watershed for optimum production with minimum

hazard to natural resources (Osbrone and Wiley, 1988; Kessler et al, 1992).

Land and Water resources are limited and their wide utilization is imperative,

especially for counties like India, where the population pressure is increasingly

continuous. These resource development programmes are applied generally on

watershed basis and thus prioritization is essential for proper planning and

management of natural resources for sustainable development (S. Srinivasa,

Vittala, S. Govindaiah and H. Honne Gowda, 2008).

Watershed prioritization is the ranking of different micro-watersheds of a

watershed according to the order in which they have to be taken up for

development (Binay Kumar, Uday Kumar, 2011).

Holistic integrated planning, involving remote sensing and GIS has been found to

be effective in planning for regional development based on watershed approach.

Earlier, prioritization of watersheds using remote sensing and Geographical

Information System (GIS) data has been successfully attempted by several

workers. Remote sensing and geographical information system help in the


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creation of a database for the watershed which is very much useful for carrying

out spatial analysis thereby helping the decision makers in framing appropriate

measures for critically affected areas (Thakkar and Dhiman 2007; Magesh et al.

2011; Srivastava et al. 2011, 2012a, 2012c, Mukherjee et al. 2007, 2009). It is

an effective tool for integration of spatial data to derive useful outputs and for

modeling (Gupta and Srivastava 2010; Srivastava, et al. 2010; Pandey et al.

2012; Srivastava et al. 2012b, d; Thakur et al. 2012). Nooka Ratnam et al.

(2005) has carried out check dam positioning by prioritization of micro-

watersheds using morphometric analysis. By prioritization of watersheds, one can

conclude which watershed can lead higher amount of discharge due to excessive

amount of rainfall (Thomas et al. 2012). Recently, Patel et al. (2012) has

reported a case study to select suitable sites for water harvesting structures in

Varekhadi Watershed, a part of Lower Tapi Basin (LTB), Surat district, Gujarat

State, India by overlaying of Digital Elevation Model (DEM) and Shuttle Radar

Topography Mission DEM, Soil map and Slope map using RS and GIS approach.

The present study is focused on prioritization of micro-watersheds of Hathmati

watershed of Idar taluka of Sabarkantha district, Gujarat State, India, based on

GIS concept through morphometric analysis. The prioritization concept is helpful

to understand the morphology of individual watersheds (Hlaing et al. 2008;

Javed et al. 2011; Brooks et al. 2006; Strahler 1957), whereas GIS is useful in

positioning the ideal site for water harvesting structure (Gupta et al. 1997;

Chowdary et al. 2009; Kumar et al. 2008), Morphometric analysis and

prioritization of watersheds are very important for water resource modeler and

flood management (Youssef et al. 2011; Miller and Craig Kochel 2010; Bali et

al. 2012).

Through prioritization, prediction and estimation of discharge in a particular

watershed could be calculated during the high rainfall event. The erodibility of

catchment can also be estimated as it is depended on the rainfall and discharge

occurring over a catchment (Bagyaraj et al. 2011; Dawod et al. 2012). These

results are of utmost importance to conserve water and soil and can also be used

for designing efficient water harvesting structures in a watershed. The positioning


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of water harvesting structures through GIS and RS will save a lot of expenses,

labor and analysis, particularly for the remote areas. These structures directly

check the excessive water coming from the watersheds and hence lead the soil and

water conservation. Thus, study envisages suitability for water harvesting

structures in watershed, which can help to increase water potential for irrigation

and domestic purpose as well as for controlling the excess runoff which

sometimes takes a form of floods. The study area constitute a part of an arid or

semi-arid region in Gujarat State, India having low rainfall with high intensity of

rainfall were excessive runoff and soil erosion have caused low moisture intake

leading to poor crop production and which needs adoption of soil and water

conservation measures.

The present study aims at identification of suitable sites for water harvesting

structures (Check Dam, Nallah/Gully plugs, and Boulder bunds) based on micro-

watershed prioritization by using remote sensing data, GIS techniques and also

through morphometric studies. The methodology to be adopted is presented in

Fig. 7.1.


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Fig. 7.1 : Methodology for Location of Water Harvesting Structures


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7.4 STUDY AREA

The Hathmati watershed of Idar taluka of Sabarkantha district is selected as a

study area having 1082.62 km2 areas. Hathmati River is the principal tributaries of

Sabarmati river. The Hathmati River rises from the Gujarat Malwa hills south

western foothills of the Rajasthan range near Godad at north latitude of 23°55' and

an east longitude of 73°29' in Sabarkantha district. After traversing a course of 98

km, it meets the Sabarmati River near Ged, 20 km south west of Himatnagar in

Sabarkantha district. The two main tributaries of Hathmati are Bodoli and Guhai

having catchment areas of 119 km2 and 505 km2, respectively. The average annual

rainfall in the catchment is 860 mm. The study areas falls in Survey of India (SOI)

Topographical maps (Toposheets) No. 46-A-13, 46-A-14, 46-E-01, 46-E-02, 46-

E-05 and 46-E-06. Following table shows general features of the Hathmati basin.

Table 7.1 General Features of Hathmati Watershed

Geology Rocks followed by alluvial plains

Physiography Gently sloping pediments to gently sloping

alluvial plain

Runoff High to low

Water Holding Capacity Good

Groundwater Formation Semi confined to and unconfined aquifers

Irrigability Good

Forests Traditionally well forested, now degraded

Main Community Caste based agrarian communities

dominated by Patidars and Chowdharies

The Wet seasons sets in by the middle of June and withdraws by the middle of

October. About 90% of the rainfall occurs during the Wet season (June-October)

and during the rest of the year (dry season) there is very little rainfall with no

regular pattern. Typical tropical climate prevails in the basin for better part of the

year. For practical considerations two seasons dry (December-May) and Wet

(June-November) seasons exist in the area. Mean annual runoff in the catchment


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is 123 Mm3. The catchment is of "leaf or fern type" which is having gently sloping

pediments to gently sloping alluvial plain. The river basin has various land use

patterns, of which agricultural land use (double crop-35%; single crop-25%),

forests (15%), waste land (15%) and mixed land use (10%) are the important land

use classifications. Number of villages under submergence is one partial and six

full. The river and its tributaries flow through different terrain having varied land

use activities, soil conditions, vegetation and agricultural practices. The water

potential of the river Hathmati is mainly used for drinking, industries, irrigation

and flood control. Refer location maps (Fig. 7.2 to 7.4)


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Fig: 7.2 Location Map


196

Fig: 7.3 District Map


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Fig. 7.4 Taluka Map


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Fig: 7.5 Hathmati River map


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7.5 GENERATION OF THEMATIC MAPS

As a scientific study of the earth advanced, so new material needed to be mapped.

The developments in the assessment and understanding of natural resources like

Geology, Geomorphology, Soil science, Ecology, and Land that began in the 19th

century and have continued to this day provided new material to be mapped.

Whereas topographical maps can be regarded as general purposes because they do

not set out to fulfill any specific aim (i.e., they can be interpreted for many

different purposes), maps of the distribution of rock types, soil series or Landuse

are made for more limited and specific purposes.

The specific purposes maps are often referred to as “Thematic” maps because they

contain information about a single subject or themes. To make the thematic data

easy to understand, thematic maps are commonly drawn over a simplified

topographic base by which user can orient themselves.

Various thematic maps were prepared for the study area from SOI Toposheet,

Satellites data and other ancillary data. These maps have been prepared at

1:50,000 scales. These have been compiled and studied individually as well as in

relation to each other.

7.6 GENERAL METHODOLOGY FOR PREPARATION OF

THEMATIC MAPS:

Various thematic maps were prepared for the study area from SOI Toposheets,

Satellites data and other ancillary data. These maps have been prepared at

1:50,000 scales. In this study, IRS P6 PAN + LISS IV geocoded data were used.

With the help of image interpretation or recognition element such as tone, texture,

size, shape, association, feature, etc. various thematic classes were identified and

verified with the ground truth. The interpreted thematic details were transferred

and finally the following particular thematic maps were prepared.

Base map

Drainage map


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Watershed map

Slope map

Land use/Land cover map

Contour map

Elevation map (DEM)

7.6.1 Base map

This map is prepared directly from the SOI Toposheets maps Fig. 7.6 and 7.7

which is used to derive the basic information of the study area such as Road

networks, Rail networks, River, Settlements, Tanks, Canals, etc. This information

is updated with the Satellite images. The basic information thus prepared shows

the study area boundary and other information.

7.6.2 Drainage map

Drainage map of the study area has been delineated using Toposheet and satellite

imagery. All the drainages were traced out and map was prepared. Then this

drainage is super imposed with satellites images data and the changes in the

drainage courses were mapped. The drainage map was shown in Fig. 7.8. The

drainage map has been later used to delineate watershed boundaries.

7.6.3 Watershed map

Watersheds are natural hydrological entities that cover a specific areas extent of

landform which rainwater flow to a defined gully, stream or river at any particular

point. The size of the watershed depends upon the size of the stream or river and

the point interception of the streams or river and density and distribution of

drainage.

The All India Soil and Land Use Survey, Ministry of Agriculture and cooperation

(AIR & LUS), New Delhi, have developed system watershed delineation like

water resources Region, Basin, Catchments, Sub catchments and watershed. The

surface water bodies have been studied and delineated using satellite imagery.


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Watershed boundaries are delineated using drainage and surface water bodies’

maps. Drainage map with the details of water bodies and watershed boundary is

shown in Fig. 7.9. Table 7.2 shows the watershed wise area.

Table 7.2 : Watershed wise areas

Sr.No. Watershed Code Area (Sq.Km.)

1 MW 1 73.70

2 MW 2 72.72

3 MW 3 54.47

4 MW 4 38.56

5 MW 5 137.00

6 MW 6 106.41

7 MW 7 56.50

8 MW 8 90.80

9 MW 9 66.82

10 MW 10 138.65

11 MW 11 59.05

12 MW 12 25.64

13 MW 13 162.30

Total 1082.62 km2

7.6.4 Slope map

Slope is a very important factor for watershed prioritization. If the slope is higher

degree there is a chance for more run off, infiltration is less, and automatically

erosion is more. In the present study slope is prepared using SRTM data. Slopes

study classified on the basis of the guidelines mentioned in Integrated Mission for

Sustainable Development (IMSD) document. Finally, slope coverage has been

readied as one of the coverage in the integrated analysis. The study area is found


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to be very gently sloping. The slope map is shown in Fig. 7.10, Table 7.3 show

the different slope categories obtained and their areal distribution in the study

area.

Table 7.3 : Percent are under various slope classes

Slope class Slope category Slope %)

1 Nearly level 0 – 1

2 Very gently sloping 1 – 3

3 Gently sloping 3 – 8

4 Moderately sloping 8 – 15

5 Strongly sloping -

6 Moderately steep to steeply sloping -

7 Very steep sloping -

7.6.5 Land use /Land cover map

To evaluate the land use /land cover condition of the study area satellite imagery

is used. The interpretation and correlation of imagery with object involved the

comparison of spectral response of each type of object with tinge characteristics.

Monoscopic visual interpretation of IRS-P6 LISS III geo-coded FCC of 2010 on

1:50,000 scales are done for identification of different land use/land cover classes.

The interpreted details are checked on ground to verify the Interpretation and

doubtful areas. Based on the ground verification, boundaries of the different land

use/ land cover units are finalized. Double-cropped area is largely lying in areas

where irrigation facilities are available. The land use/land cover map is shown in

Fig.7.11. Various land use categories present in the study area are described

below:

Habitation:

This class of land is identified as mixed type of residential urban or rural cover,

which includes low rise and detached buildings and slums. Here industrial area is


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found as the main business for the people living there. Habitation is identified as

mottled gray with coarse texture.

Agriculture land :

This class of land is broadly defined as the land, which is used primarily for

production of field crops. Tobacco, paddy, wheat, etc. are the major crops grown

in the study area. Agricultural land is further classified into (a) double cropped

(Kharif and Rabi) area, (b) single cropped (Kharif) area. Double cropped area is

defined as the area, which is cultivated more than once in a year. Single cropped

area is defined as the area, which is cultivated during one season in the year,

agriculture land is identified mainly on basis of pinkish- red tone, fine texture and

its pattern.

Waste land

Wasteland can be broadly defined as the land which is degraded due to various

factor such as erosion, salinity, water –logging, mining, desertification, etc., there

by a posing problem to ecological balance in that area. Wasteland is further

classified into:

(a) Waste land with scrub

(b) Waste land without scrub

Wasteland with scrub is area with scant scrub vegetation. Wasteland without scrub

in the study area is an area without any vegetation.

Water bodies

This class of land includes ponds, lakes, depression storage, perennial

rivers/stream, etc. water bodies are identified mainly on the basis of dark

blue/black tone.


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Fig. 7.6 Grid Map


205

Fig. 7.7 Toposheets Map


206

Fig. 7.8 Drainage Order Map


207

Fig. 7.9 Watershed map


208

Fig 7.10 Slope map


209

Fig. 7.11 Land use / Land cover Map


210

Fig. 7.12 Contour Map


211

Fig. 7.13 DEM Map


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7.7 MORPHOMETRIC ANALYSIS

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). Morphometric analysis refers to the quantitative

analysis of form, a concept that encompasses size and shape. Morphometric

analysis requires measurement of linear features, areal aspects, gradient of channel

network and contributing ground slopes of the drainage basin (Nautiyal, 1994).

The morphometric assessment helps to elaborate a primary hydrological diagnosis

in order to predict approximate behaviour of a watershed if correctly coupled with

geomorphology and geology (Esper, 2008). The hydrological response of a river

basin can be interrelated with the physiographic characteristics of the drainage

basin, such as size, shape, slope, drainage density and size, and length of the

streams, etc. (Chorley, 1969, Gregory and Walling 1973). Hence, morphometric

analysis of a watershed is an essential first step, towards basic understanding of

watershed dynamics. Morphometric is the measurement and mathematical

analysis of the configuration of the earth's surface, shape and dimensions of its

land forms (Clarke, 1996). The morphometric characteristics at the watershed

scale may contain important information regarding its formation and development

because all hydrologic and geomorphic process occur within the watershed

(Singh, 1992). This analysis can be achieved through measurement of linear,

aerial and relief aspects of basins by using the approach of remote sensing and

GIS.

Remote sensing and GIS techniques are currently 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 satellite remote sensing has the ability of obtaining

synoptic view of large area at one time and very useful in analyzing the drainage

morphometric (Swati Uniyal and Peeyush Gupta, 2013). Pioneering work on the

drainage basin morphometric has been carried out by Horton (1932, 1945),

Miller (1953), Smith (1950), Strahler (1964) and others. In India, some of the

recent studies on morphometric analysis using remote sensing technique were

carried out by Nautiyal (1994), Srivastava (1997), Nag (1998), Shrimali et al.


213

(2001), Khan et al. (2001), Srinivasa et al. (2004). Chopra et al. (2005) have

carried out morphometric analysis of sub-watersheds in Gurdaspur district,

Punjab. A study on characterization and management of watersheds in

Ganeshapur watershed of Nagpur district was carried out by Solanke et al.

(2005).

Prioritization of sub-watersheds based on morphometric analysis of drainage

basins using RS and GIS techniques, was attempted by Biswas et al. (1999).

Nooka Ratnam et al. (2005) carried out check dam positioning by prioritization

of micro-watersheds using Silt Yield Index (SYI) model and morphometric

analysis using RS and GIS in Midnapur district of West Bengal. Arun et al.

(2005) attempted a rule based physiographic characterization of draught prone

watershed applying remote sensing and GIS techniques in Gandeshwari watershed

in Bankura district of West Bengal. Amee and Dhiman (2007) have carried out

morphometric analysis and prioritization of eight mini watersheds of Mohr

watershed, located between Bayad taluka of Sabarkantha district and Kapadwanj

taluka of Kheda district in Gujarat State, India using RS and GIS techniques.

More recently, Dhruvesh Patel, Chintan Gajjar and Prashant Srivastava

(2012) have carried out morphometric analysis and prioritization of ten mini-

watersheds of Malesari Watershed, situated in Bhavnagar district of Saurashtra

region of Gujarat state, India using RS and GIS techniques. In the present study,

morphometric and land use/land cover analysis have been carried out in Hathmati

Watershed of Sabarkantha district, Gujarat state, India using remote sensing and

GIS techniques.

7.8 MORPHOMETRIC PARAMETERS

The drainage basin morphometric study has to pass through the most important

stage called stream ordering. Various methods have been suggested for this

purpose, but the most popular and most simple ordinal scale of stream ordering

used by Strahler 1964 is being followed here. The characteristics of a basin and of

the streams making up the drainage system can be represented quantitatively using

indices of basin shape and relief and of linkage in the channel network. Many of

the indices are ratios, meaning that they can be used to characterize and compare


214

basins of different sizes. The details of the drainage morphometric parameters of

the main basin are presented below.

7.8.1 Characteristics of Catchments

The hydrologic behavior of a catchment depends on certain characteristics of the

drainage basin. These characteristics are mainly related to the physical drainage

basin or to the channel. The physical characteristics of a catchment are drainage

area, its shape, slope, centroid etc. The channel characteristics are channel order,

its length, slope, profile and drainage density. Many of these characteristics can be

determined easily with the aid of computers.

7.8.1.1 Drainage-Area Characteristics

The drainage–area characteristics of the basin, as under, are determined from the

Topographic maps, soil maps, crop reports and reconnaissance of the area, i)

proportion of catchment under cultivation, ii) culture, kind and extent of crops

grown, etc, iii) area under forests, iv) grassland area, v) area under habitation,

town and cities.

7.8.1.2 Basin Order and Channel Order

The concept of channel order was introduced by Horton and Strahler to describe

the basins in quantitative terms. This concept is used with the linear dimension of

the channel length. The stream orders are designated to the available channel

network. The first order stream has no tributary. Its flow depends entirely on the

surface overland flow to it (Fig.7.14). The second-order channel is formed by the

junction of two first-order channels and as such has higher surface flow.


215

Fig. 7.14 Channel order

Likewise, the third-order channel receives flow from two second-order channels

and may in addition receive flow from first order channel or second-order channel

which empty directly into it. Thus the drainage basin is described as first, second,

or higher order depending upon the stream order at the outlet. The order of the

basin is the order of its higher-order channel.

7.8.1.3 Basin Area

The flow from a drainage basin is a function of the area of the basin. Basin area is

the area contained within the vertical projection of the drainage divide on a

horizontal plane. It is measured in square kilometer, hectares. The closed drainage

areas such as swamps, lakes that do not contribute runoff to the drainage system

are excluded from the total drainage area to get the affective drainage area.

Likewise, there may be underground leakage from one basin to another which

means larger affective drainage area from the leakage is transmitted. The area of a

basin of a given order is computed by drawing the perimeter of all first, second

and higher order of basins on the topographic map of the basin. The flow from a

basin is related to the area by the relation Q = CAm . It is a very simple but

important relation between the drainage area and discharge.

7.8.1.4 Basin Shape


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The catchments may be of symmetrical or irregular forms. The shape may

resemble a Pear shape, U-shape or a V-shape valley as shown in Fig. 7.15 a,b & c.

Fig. 7.15 Basin shapes.

The shape characteristics of a catchment are generally expressed by form factor

and compactness coefficient.

(a) Form factor, Ff

The form factor is an index expressing the relation of average width to the axial

length of basin, to measure the shape characteristics.

2

/

lA

llA

lBFf (7.1)

Where, l = axial length from outlet to the remotest point in the basin, and B=

average width obtained by dividing the area (A) by axial length.

(b) Compactness coefficient, Cc

It is the ratio of perimeter of the catchment to the circumference of a circle whose

area is equal to that of the catchment. This coefficient is independent of the size of

the catchment and is dependent only on the shape.

sin

sin

BaofareathetoequalisareawhosecircleofnceCircumfereBaofPerimeterCc (7.2)


217

5.02821.0

22 AP

RP

APCc

(7.3)

Where, P = perimeter of basin (km) , A = area of basin (sq. km) and R = radius of

the circle of equivalent area(km).

(c) Elongation Ratio, Re.

Re is defined as the ratio of basin area to the area of circle having the same

perimeter as the basin = 2R/L. The values vary between 0.2 to 0.8.

502 .

be /A

LR (7.4)

Where, Lb is the maximum length (ft) of the basin parallel to the principal

drainage lines.

(d) Basin Length, Lb

Lb is the longest dimension of a basin parallel to its principal drainage channel.

Lb= 1.312A0.568 (7.5)

7.8.2 Drainage Density

Drainage density is expressed as total length of all streams, perennial and

intermittent, per unit area of the basin. It is an index of the a real channel

development in the catchment

Dd = L/A (7.6)

Where, Dd is drainage density (km/sq km), L is total length of all streams in the

catchment (km) and A is area of catchment (km2).

High value of density indicates well developed network and torrential runoff

likely to cause violent flood, while a low value signifies a less developed network

and a modest runoff which is explained by high permeability of the terrain.


218

7.8.3 Average Altitude

Elevation of the basin varies from point to point. The average elevation or altitude

is computed by multiplying each increment of area by its mean elevation and the

sum of the product divided by the drainage area. The weighted mean altitude is

determined by dividing the sum of the product of contour length and respective

elevations by the total length of contours. In the case of large basins, depending on

the scale, the area s divided into square of suitable size, say 1 to 250 km sides and

the elevations at the intersections of all squares are tabulated and averaged. The

median elevation or the elevation at 50 percent area of the catchment is

determined from the area-elevation curve called Hypsometric curve (Fig. 7.16)

The area-elevation curve is obtained by plotting elevation against area, or

percentage of area, above or below a given elevation.

Fig. 7.16 Hypsometric curve

7.8.4 Average Land Slope

The slope of the catchment varies from point to point. The average slope is equal

to the total length of contours multiplied by the contour internal and divided by


219

the area of the catchment. It is a laborious method. The land slope is determined

from a grid established on the contour plan of the catchment generally in north-

south and east-west lines. For smaller catchments of 250 sq.km or less minimum

four grid lines crossing the basin in each direction are required, for large

catchments-more grid lines are required than those indicated for smaller

catchments, and for very large catchments-at least one grid in each direction for

each 250 sq.km of catchment area is required. The length of each line is measured

and number of contours crossed counted. According to Horton, the area whose

slope is to be determined I sub-divided by a grid into a number of squares of equal

size. The number of contours crossed by each sub-dividing line is counted and the

lengths of the grid lines are scaled. The slope of the catchment is given by the

relation,

S = DN/L (7.7)

Where, S = slope of catchment, D = contour interval, N = number of contours

crossed by all the sub-dividing lines, and L = total length of the sub-dividing lines.

7.8.5 Average Stream Slope

Average stream slope is determined by tabulating lengths and elevations of the

stream channel and its major tributaries and a properly weighted mean slope is

computed. Usually, it is taken as total fall between the points divided by the

stream length. A better and realistic mean stream slope is that which has the same

area under it as does the profile.

7.8.6 Basin Centroid

It is the location of the point within the drainage basin that represents the weighted

centre of the basin. It is the first moment of the area about the origin.

7.8.7 Basin Similarity

The drainage-basin similarity may be (i) geometric similarity (i.e., in terms of

basin area, shape, main channel slope, topography), (ii) hydrologic similarity (i.e.,


220

in terms of snowfall, rainfall, runoff, infiltration, valley storage), and (iii) geologic

similarity (i.e., relating to ground water flow, soil erosion, sediment

characteristics).

7.8.8 Channel Length

It is the length of channels of each order. The first order channels are of short

length and the length increases geometrically, as the order Increases.

7.8.9 Channel Profile

It represents the relationship between the altitude and horizontal distance. It is

determined from topographic map of a basin. Generally the channel profile is

concave upward. The concavity is a function of the basin geology and

precipitation. The upper part of the channel profile is generally steeper than the

lower portion in a drainage basin of fairly uniform geology.

7.8.10 Overland Flow Length

The maximum length of surface flow traversed by rain water flow towards a

channel is called length of overland flow (Lo).

Lo = 1/2Dd, (7.8)

Where Lo is length of overland flow, (km) and Dd is drainage density (km-1).

7.8.11 Drainage Pattern

The pattern of the tributary system depends on various factors such as physical

characteristics of the area, nature of rock formation and their erodibility. The

drainage pattern may be classified, as under, depending on the shape of the

catchment and stream pattern.

1. Tree-like Type


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In homogeneous rocks structure regions there is little variation in the

resistivity of the rock to influence stream pattern, the resulting streams

running in all directions are called dendrites or tree-like type (Fig. 7.17).

2. Rectangular Type.

The region with many rectangular joints and faults results in a system of

valleys joining at nearly right angles. Such a drainage pattern is termed as

rectangular type. It follows no rule with regard to the size and direction of the

stream. Usually it shows two directions, nearly at right angles to each other

(Fig.7.18) and as such there are numerous right angle turns in the river

course, with the tributaries discharging perpendicularly into the next larger

generation.

Fig. 7.17 Tree Type. Fig.7.18 Rectangular Type.

3. Radial Type

It represents the drainage pattern wherein a number of streams usually radiate

outward from a central focus (Fig.7.19). Adjacent channels emptying into

each other form streams system which individually tend to be of parallel type.


222

Fig. 7.19 : Radial Type

4. Trellis Type

In the region where the underlying rock is strongly folded or sharply dipping

a trellis type drainage pattern is developed. The characteristic of the pattern is

that the orientation followed by some streams is towards one side and by

others to the opposite side. The orientation of the other streams being at right

angle to this, likewise towards two directions (Fig.7.20). A simple form of

trellis pattern is called annular pattern wherein the subsequent streams which

form in the weaker strata of a dome mountain define a roughly circular, or

annular pattern. The longer streams are subsequent and follow weaker rock

strata, while the shorter tributaries are either obsequent or resequent.

5. Parallel Type

In this pattern of catchment (Fig.7.21) both the main stream and tributaries

are in parallel because of pronounced inclination or internal geological

structure of the region.


223

Fig. 7.20 Trellis Type. Fig. 7.21: Parallel Type.

7.8.12 Classification of Catchments

Large river basins usually tend to be of fan-shaped or pear-shaped but smaller

basins exhibit greater variation in shape depending on the geological structure of a

basin. The two usual classifications of the catchments are fern-leaf type and fan-

shaped type.

1. Fern-leaf Type.

The fern-leaf type catchment is relatively narrow (Fig.7.22) possessing the

main characteristics such as (i) indicative of smaller peak discharge, (ii) the

discharges are likely to be distributed over a longer period of time, (iii) the

tributaries meet the main stream at almost regular intervals, and (iv) the

tributaries are generally of different sizes and lengths, (v) the peak of the

flood runoff reaches a point on the main stream at different times resulting in

smaller floods.


224

Fig. 7.22 Fern-leaf shaped catchment

2. Fan-shaped Type

The fan-shaped type catchment, as the name implies, extends in the shape of

a fan from a point and is wider (Fig.7.23) possessing the main characteristics,

(i) indicative of incidence of high floods, (ii) time of concentration of runoff

is nearly the same in all tributaries, (iii) the tributaries are nearly of the same

size, (iv) the peak flood from the various tributaries reaches the main stream

approximately at the same time, (v) and the tributaries meet the main stream

approximately at the same place.

Fig. 7.23 Fan-shaped catchment

7.8.13 Classification of Streams


225

The streams are classified according to the base flow components of their

discharge, as under:

7.8.13.1 Perennial Stream

The stream which flows all the year round is called perennial stream. The flow in

non monsoon season may be due to ground water regeneration or snow melt in

high altitudes. The stream bed is below the ground water table to collect ground

water.

7.8.13.2 Intermittent Stream

The stream which flows during monsoon and by regeneration of ground water but

dry up practically in summer is called intermittent stream. The stream bed is

intermittently below the ground water table in wet season and drops below the

water table in dry season

7.8.13.3 Influent stream

The stream which has its bed level lower than ground water table so that seepage

from it feeds the ground water table is termed as influent stream.

7.8.13.4 Effluent Stream

The stream which has bed level lower than ground water table and is fed by high

water table is called effluent stream. Most of the perennial rivers belong to this

category, the base flow being the effluent seepage from the catchment.

7.8.13.5 Ephemeral Stream

The stream which flows only during storm runoff of short duration, as in arid

regions, and dry up completely in non-monsoon period is called ephemeral

stream. A stream which is perennial, intermittent or ephemeral throughout its

course is termed as continuous. The stream which changes its classification in

various reaches of its course is called an interrupted stream.


226

Table 7.4 Morpho Metric Parameters

1 568.0b A312.1L Basin Length

2 A

LDd Drainage Density

3 A

NFu Stream Frequency

4 do D2

1L Length of The Overland Flow

5 1u

ub N

NR

Bifurcation Ratio

6 b

fL

AR Form Factor

7 A

LB

2b

s Shape Factor

8 5.0

be

/A

L/2R

Elongation Ratio

9 22c P

A57.12

P

A4R

Circularity Ratio

10 5.0c A

P2821.0C Compactness Ratio

11 P

NT 1 Texture Ratio


227

Where,

Lb : Basin Length Is In Km

A : Area of the Basin in Km2

P : Perimeter in Km

Dd : Is the Drainage Density

L : Is the Total Length of All Channels of All Order In The Drainage Basin

N : Total no. Of Streams

N1 : Total No. Of First Order Streams

Lo : Length of the Overland Flow In Km

Rb : Bifurcation Ratio

Nu : No. Of Streams of Order

Nu+1 : No. Of Streams of Next Higher Order

Rf : Form Factor (Rf<1)

Bs : Shape Factor (Bs>1)

Re : Elongation Ratio (Re<=1)

Rc : Circularity Ratio (Rc<=1)

Cc : Compactness Coefficient (Cc>=1


228

Table 7.5 : Description of Indicators of Prioritization

Parameter Characteristics

Linear

Stream Order It is defined as a measure of the position of a stream in the hierarchy of tributaries.

Mean Stream Length (Lsm) The mean stream length is the characteristic property related to the drainage network and its associated surfaces. Generally higher the order, longer the length of streams is noticed in nature.

Drainage Texture (T) It is the total number of stream segments of all orders per perimeter of the area

Bifurcation Ratio (Rb) Bifurcation ratios characteristically range between 3.0 and 5.0 for basins in which the geologic structures do not distort the drainage pattern.

Drainage Density (Dd) Drainage density (Dd) shows the landscape dissection, runoff potential, infiltration capacity of the land, climatic conditions and vegetation cover of the basin. High drainage density is the resultant of weak or impermeable subsurface material, sparse vegetation and mountainous relief. Low drainage density leads to coarse drainage texture while high drainage density leads to fine drainage texture.

Stream Frequency (Fs) Stream Frequency is the total number of stream segments of all orders per unit area. Generally, high stream frequency is related to impermeable sub-surface material, sparse vegetation, high relief conditions and low infiltration capacity.

Shape

Form Factor (Ff) Form factor is defined as ratio of basin area to the square of basin length The value of form factor would always be less than 0.7854 (for a perfectly circular basin) Smaller the value of form factor, more elongated will be the basin. The basins with high form factors have high peak flows of shorter duration, whereas, elongated watershed with low form factors


229

have lower peak flow of longer duration.

Circulatory Ratio (Rc) It is defined as the ratio of basin area to the area of circle having the same perimeter as the basin and is dimensionless. Circulatory Ratio is helpful for assessment of flood hazard. Higher the Rc value, higher is the flood hazard at the peak time at the outlet point.

Elongation Ratio (Re) Elongation ratio (Re) is defined as the ratio of diameter of a circle of the same area as the basin to the maximum basin length. It is a very significant index in the analysis of basin shape which helps to give an idea about the hydrological character of a drainage basin. Values near to 1.0 are typical of regions of very low relief

Compactness Co efficient (Cc) Compactness Co efficient (Cc) is used to express the relationship of a hydrological basin with that of a circular basin having the same area as the hydrologic basin.

7.9 METHODOLOGY AND APPLICATION

The remote sensing image presented in chapter 2, is geometrically rectified with

respect to Survey of India (SOI) topographical map on 1:50,000 scale. The

drainage pattern was initially derived from SOI toposheet and later updated using

linearly stretched False Color Composite (FCC) IRS-P6 LISS IV satellite data.

Some of the first order drainage streams were updated from satellite data. The

drainage pattern delineated for watershed was exported to ARC/INFO GIS

software for morphometric analysis. For better accuracy of the thematic map,

ground truth check is done for verification and necessary modifications are made

in thematic maps during post interpretation.

The various morphometric parameters such as area, perimeter, stream order,

stream length, stream number, bifurcation ratio, drainage density, stream

frequency, drainage texture, length of basin, form factor, circulatory ratio,


230

elongation ratio, length of overland flow, compactness coefficient, shape factor,

texture ratio were computed based on the formula suggested by (Horton, 1945),

(Strahler, 1964), (Schumm, 1956), (Nooka Ratnam et al. 2005) and (Miller,

1953) given in Table 7.4.

The stream ordering is carried out using Horton's law. The fundamental

parameters namely; stream length, area, perimeter and number of streams are

derived from the micro watershed layer and basin length was calculated from the

stream length. Bifurcation ratio was calculated from the number of streams. The

other parameters were calculated from area, perimeter, basin length and stream

length.

The linear parameters such as drainage density, stream frequency, bifurcation

ratio, drainage texture, length of overland flow have a direct relationship with

erodibility, higher the value, more is the erodibility. Hence for prioritization of

micro-watersheds, the highest value of linear parameters was rated as rank 1,

second highest value was rated as rank 2 and so on, and the least value was rated

as last in rank. Shape parameters such as elongation ratio, compactness

coefficient, circularity ratio, basin shape and form factor have an inverse

relationship with erodibility (Nooka Ratnam et al., 2005), lower the value, more

is the erodibility. Thus the lowest value of shape parameters was rated as rank 1,

next lower value was rated as rank 2 and so on and the highest value was rated last

in rank. Hence, the ranking of the micro watersheds has been determined by

assigning the highest priority/rank based on highest value in case of linear

parameters and lowest value in case of shape parameters.

The prioritization was carried out by assigning ranks to the individual indicators

and a compound value (Cp) was calculated. Watersheds with highest Cp were of

low priority while those with lowest Cp were of high priority. Thus an index of

high, medium and low priority was produced. Prioritization rating of all the

thirteen micro-watersheds of Hathmati watershed was carried out by calculating

the compound parameter values.


231

Table 7.6 Stream Order of Sub-watershed

Watershed Code No.

1st

Order 2nd

Order 3rd

Order 4th

Order 5th

Order 6th

Order

Total No. of

Streams

MW 1 114 61 31 17 – – 216

MW 2 191 105 39 28 – – 355

MW 3 82 40 30 10 2 – 151

MW 4 70 31 9 20 19 – 147

MW 5 202 95 40 33 20 – 388

MW 6 128 69 37 6 26 – 261

MW 7 59 37 10 2 13 – 116

MW 8 118 68 30 15 2 9 239

MW 9 27 15 7 7 – – 56

MW 10 178 85 69 15 15 5 359

MW 11 42 24 3 14 – – 81

MW 12 45 24 13 7 – – 89

MW 13 241 112 54 18 55 – 478


232

Table 7.7 Morphometric Parameters

Micro- Water-

shed Code No.

Area (A) km2

Peri-meter

(P) km

Total Length of all

streams of all

orders (L) Km

Total No. of

Streams (N)

Total No. of First

orders streams

(N1)

Basin Length

(Lb) km

Bifur-cation ratio (Rb)

Drain-age

Density (Dd) Km/ Km2

Stream Fre-

quency (Fu)

No/Km2

Texture ratio (T)

Length of

overland flow (LO)

Form factor (Rf)

Shape factor (Bs)

Elong-ation ratio (Re)

Compactness

coefficient (Cc)

Circularity ratio (Rc)

MW 1 73.70 57.10 131.75 216 114 15.089 1.887 1.788 2.931 1.996 0.894 0.324 3.089 0.642 1.876 0.284

MW 2 72.72 71.96 189.98 355 191 14.975 1.968 2.612 4.882 2.654 1.306 0.324 3.084 0.642 2.380 0.177

MW 3 54.47 45.08 98.24 151 82 12.708 2.846 1.804 2.772 1.819 0.902 0.337 2.965 0.655 1.723 0.337

MW 4 38.56 64.88 91.05 147 70 10.444 2.059 2.361 3.812 1.079 1.181 0.354 2.829 0.671 2.947 0.115

MW 5 137.00 110.85 234.43 388 202 21.458 1.841 1.711 2.832 1.822 0.856 0.298 3.361 0.615 2.672 0.140

MW 6 106.41 85.75 175.07 261 128 18.589 2.529 1.645 2.453 1.493 0.823 0.308 3.247 0.626 2.345 0.182

MW 7 56.50 64.18 80.90 116 59 12.975 2.612 1.432 2.053 0.919 0.716 0.336 2.980 0.653 2.409 0.172

MW 8 90.80 86.11 146.59 239 118 16.987 2.001 1.614 2.632 1.370 0.807 0.315 3.178 0.633 2.549 0.154

MW 9 66.82 58.70 56.16 56 27 14.272 1.648 0.840 0.838 0.460 0.420 0.328 3.048 0.646 2.026 0.244

MW 10 138.65 104.14 215.74 359 178 21.605 2.642 1.556 2.589 1.709 0.778 0.297 3.366 0.615 2.495 0.161

MW 11 59.05 46.67 69.81 81 42 13.304 3.321 1.182 1.372 0.900 0.591 0.334 2.997 0.652 1.713 0.341

MW 12 25.64 42.08 55.50 89 45 8.283 1.859 2.165 3.471 1.069 1.082 0.374 2.676 0.690 2.344 0.182

MW 13 162.30 109.79 133.04 478 241 23.626 1.888 0.820 2.945 2.195 0.410 0.291 3.439 0.608 2.431 0.169


233

Table 7.8 Compound Value of Morphometric Parameters

Watershed Code No. Rb Dd Fu T Lo Rf Bs Re Cc Rc (=Sum)

Compound Value (Cp) Rank

MW 1 10 5 5 3 5 7 8 6 3 11 63 6.3 4

MW 2 8 1 1 1 1 6 7 7 7 7 46 4.6 1

MW 3 2 4 7 5 4 11 3 11 2 12 61 6.1 2

MW 4 6 2 2 9 2 12 2 12 13 1 61 6.1 3

MW 5 12 6 6 4 6 3 11 3 12 2 65 6.5 5

MW 6 5 7 10 7 7 4 10 4 6 8 68 6.8 7

MW 7 4 10 11 11 10 10 4 10 8 6 84 8.4 11

MW 8 7 8 8 8 8 5 9 5 11 3 72 7.2 10

MW 9 13 12 13 13 12 8 6 8 4 10 99 9.9 13

MW 10 3 9 9 6 9 2 12 2 10 4 66 6.6 6

MW 11 1 11 12 12 11 9 5 9 1 13 84 8.4 12

MW 12 11 3 3 10 3 13 1 13 5 9 71 7.1 9

MW 13 9 13 4 2 13 1 13 1 9 5 70 7.0 8


234

7.10 MORPHOMETRIC ANALYSIS:

The watershed is divided into thirteen micro-watersheds with codes MW 1 to

MW 13.

The various morphometric parameters which have been used in the prioritization

of watershed are calculated and presented in Table 7.7.

Table 7.6 describes the stream order of micro-watershed. Hatmati river has a 6th

order stream covering an area of 1082.62 km2. The micro-watersheds MW-1,

MW-2, MW-9, MW-11 and MW-12 having 4th order streams. The micro-

watersheds MW-3, MW-4, MW-5, MW-6, MW-7, MW-10 and MW-13 having 5th

order streams. The micro-watershed MW-8 and MW-10 having 6th order streams.

The variation in order and size of the sub-watersheds is largely due to physio-

graphic and structural conditions of the region.

Table 7.7 shows the various calculated morphometric parameters which have

been used in the prioritization of micro-watersheds. Table 7.8 shows the 10

parameters, from which compound value (Cp) was calculated for each micro-

watershed. Watershed with lowest Cp value was given rank 1 (MW-2), next lower

value was given rank 2 (MW-3), and so on with highest Cp value was given the

last rank 13 (MW-9).

Fig. 7.24 shows the prioritized micro watersheds map of Hathmati watershed.


235

Fig. 7.24 Prioritized Hathmati Watershed


236

7.11 WATERSHED PRIORITIZATION :

The compound parameter values of all thirteen micro watersheds of Hathmati

watershed are calculated and prioritization rating is shown in Table 7.9. The

watersheds have been broadly classified into three priority zones according to

their compound value (Cp). High (< 7.0), Medium (7.0 - 8.0) and Low (8.0 and

above).

Table.7.9 Final Priority of Micro-Watersheds

Watershed Code No.

Compound Value

(Cp) Rank

Final

Priority

MW 1 6.3 4 High

MW 2 4.6 1 High

MW 3 6.1 2 High

MW 4 6.1 3 High

MW 5 6.5 5 High

MW 6 6.8 7 High

MW 7 8.4 11 Low

MW 8 7.2 10 Medium

MW 9 9.9 13 Low

MW 10 6.6 6 High

MW 11 8.4 12 Low

MW 12 7.1 9 Medium

MW 13 7.0 8 Medium

Watersheds falling under high priority are under very severe erosion susceptibility

zone. Thus need immediate attention to take up mechanical soil conservation

measures gully control structures like check dams and grass waterways to protect

the topsoil loss. While watersheds falling under low priority have very slight

erosion susceptibility zone and may need agronomical measures to check the sheet

and rill erosion. Fig. 7.25 shows prioritized micro watersheds map of Hathmati

watershed.


237

Fig. 7.25 Final Prioritized Hathmati Watershed


238

7.12 SUITABLE SITES FOR CHECK DAMS

The suitability of check dam sites can be confirmed as the site is located on third

order drainage and satisfies the conditions of land use, soil type, and slope as per

IMSD guidelines. The most of the sites in Hathmati watershed were found to be

suitable for check dam but as per ground truth and experience, 7 suitable sites are

proposed to construct the check dam (Fig.7.26). Since it is located in the suitable

land class (Scrub land, River bed), slope (less than 15%) and that serves the

purpose of soil and water conservations and groundwater augmentation. The

proposed check dams could be very useful.


239

Fig. 7.26 Suitable Sites for Check Dams


240

7.13 WATER HARVESTING STRUCTURES DETAILS

7.13.1 Check Dam

These are mostly masonry structures built across ephemeral streams to check the

surface run-off to create surface storage of water in the up-stream side of the

structure even after the monsoon season. (Fig: 7.27 & 7.28).

Fig. 7.27 Check Dam

Fig. 7.28 Check Dam


241

7.13.2 Boulder Bunds

It is a small structure constructed across the first order streams flowing through

mainly crop land area. The purpose of the structure is to prevent soil erosion and

create temporary ponding during the monsoon. It enhances the moisture region in

soil. (Fig 7.29)

Fig. 7.29 Boulder Bunds

7.13.3 Nallah / Gully Plugs

Nallah bunding is suggested at confluence of lower order streams (1st & 2nd) to

check the high velocity surface run-off and allow the water to percolate down.

Mostly these are boulder & earthen structures (Fig 7.30).


242

Fig. 7.30 Nallah/Gully plugs

Fig. 7.31 Concrete Wall


243

7.14 CLOSURE

The chapter presents the methodology for prioritization of the critically affected

watershed of Hathmati river basin of Idar taluka of Sabarkantha district with

erratic rainfall distribution. The generated thematic maps are used in the

evaluation of morphometric parameters such as a bifurcation ratio, drainage

density, and texture ratio, length of the overland flow, stream frequency,

compactness coefficient, circularity ratio, elongation ratio, shape factor and form

factor. Automated demarcation of prioritization of micro-watersheds is done by

using GIS overlaying technique by assigning weight factors to all the identified

features in each thematic map and ranks are assigned to the morphometric

parameters. Three categories of priority viz high, medium, and low are assigned to

all the watersheds.

• • •

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