International Journal of Geosciences, 2011, 2, 385-393
doi:10.4236/ijg.2011.24041 Published Online November 2011 (
Copyright © 2011 SciRes. IJG
Quantitative Estimation of Coastal Changes along
Selected Locations of Karnataka, India:
A GIS and Remote Sensing Approach
P. Vinayaraj, Glejin Johnson, G. Udhaba Dora, C. Sajiv Philip, V. Sanil Kumar, R. Gowthaman
Ocean Engineering Divisi on , National Institute of Oceanography
(Council of Scientific & Industrial Research), India
Received May 29, 2011; revised July 8, 2011; accepted August 29, 201 1
Qualitative and quantitative studies on changes of coastal geomorphology and shoreline of Karnataka, India
have been carried out using toposheets of Survey of India and satellite imageries (IRS-P6 and IRS-1D).
Changes during 30 years period are studied at each station. Significant morphological changes in landforms
like spit, channel Island, coastal plain, tidal flat, lateritic plain, alluvial plain and sand bar within and adja-
cent to estuarine river mouths of Kali, Sharavathi, Kollur-Chakkara—Haladi and Udyavara Rivers are ob-
served. The study indicates that gradual erosion is observed at i) Karwar spit along the northern side of the
Kali river mouth, ii) the spit at the southern side of the Sharavathi river mouth and iii) at some regions of
Keywords: Coastal Geomorphology, Shoreline, Coastal zone, Erosion, Accretion, Beach
1. Introduction
Coastal zone is the transition area between land and ocean
[1] and is an area of complex, dynamic and delicate e nvi-
ronment. External factors influencing the coastal zone
are the sediment supply by the rivers and coastal proc-
esses. Shoreline is one of the most rapidly changing land-
forms of the coastal zone. Geomorphic processes such as
erosion, deposition, sedimentation, periodic storms, flood-
ing and sea level changes are continuously modifying the
shoreline. The accurate mapping of shoreline is therefore
very important for planning conservation measures such
as protection of human life, property and natural envi-
ronment [2]. The coastal zone is receiving an increasing
attention because of the pressure of increasing pop ulat ion
and industrial developments. Erosion is also caused by
shifting of river mouth and spits [3]. Protection of natural
resources, the loss of habitats, severe coastal erosion,
sedimentation in ports and harbors and municipal and
industrial pollution are major concerns for coastal zone
managers [4].
Remote sensing technology had been used commonly
to map the shoreline and offers the potential of updating
maps frequently [5]. Satellite Remote Sensing (RS) tech-
nique has proved its utility in all fields of earth science
studies including the study of coastal processes, because
of the repetitive, synoptic and multispectral coverage’s
of the satellites. Satellite imageries are useful tools for
detecting the coastal morphology changes. RS data can
be used to evaluate the coastal processes like erosion/
accretion and shoreline changes. Geographic Information
System (GIS) is designed to work with data referenced
by spatial/geographical coordinates. The major advan-
tage of GIS is that it allows identifying the spatial rela-
tionships between features and temporal changes within
an area over time. Remote sensing satellites i mages have
been effectively used for monitoring shoreline changes
of different locations [6-8]. In this paper an attempt has
been made to study the shoreline changes in terms of
accretion, erosion and geomorphology using IRS-1D,
IRS-P6, toposheets data and GIS technique along Karna-
taka coast, west coast of I ndi a.
Study Area
Karnataka coastline extends over a length of 280 Km in-
tercepted with a number of riv ers joining the Arabian Sea.
Areas near the river mouths along the coastline of Karna-
taka State suffer permanent erosion due to natural shifting
Copyright © 2011 SciRes. IJG
and migration of the river mouths [9]. The present study
focused at four regions; Karwar, Honnavar, Kundapur and Malpe. Table 1 and Figure 1 present the location of
beaches under study on either side of the river mouth.
Table 1. Location data of the study area.
Stations Starting Point Ending Point Distance (Km)
Karwar (1) 14˚52'0''N 74˚6'0''E 14˚48'0''N 74˚8'0''E 7.316
Honnavar (2) 14˚20'0''N 74˚23'30''E 14˚14'30''N74˚26'30''E 10.002
Kundapur (3) 1 3 ˚40'0''N 74˚38'30''E 13˚36'0''N 74˚42'0''E 7.644
Malpe (4) 13˚22'0''N 74˚40'30''E 13˚15'0''N 74˚44'0''E 14.383
Figure 1. Location map of the study area.
Copyright © 2011 SciRes. IJG
Karwar (station 1): Karwar is one of the major
fishing zones in Karnataka. The Kali River flows through
Karwar which is also a prominent tourist destination. The
entire city of Karwar is situated on beach ridges formed
due to the influence of Kali River and Arabian Sea con-
fluence during the past [10]. The study area covers 7.316
Km and it covers north and south of the river mouth.
Honnavar (station 2): Shoreline covers 10.002 Km
and it lies on the banks of the river Sharavathi, forming
an estuary in the central west coast of India. Honnavar is
characterized by the presence of coastal alluvial soil, spit,
lateritic plain and tidal flat.
Kundapur (station 3): Study area at this station cov-
ers 7.644 Km and is situated on the confluence of Kollur-
Chakkara and Haladi rivers and Arabian Sea. Rocky
beaches, lateritic plain, alluvial plain, tidal flat and Chan-
nel Islands are the characteristics of Kundapur.
Malpe (station 4): Shoreline covers 14.383 Km and it
lies at the confluence of Udyavara river and Arabian Sea.
Malpe is the largest fishing harbour in Karnataka. Rocky
islands and barrier spit are the major characteristics of
2. Data and Methods
2.1. Data Source
IRS-1D and IRS-P6, LISS-III (cloud free) satellite image
of 26 Feb 1998 0547 hrs and 09 Jan 2008 0539 hrs, path
096 and row 062 covering the area between 74.1079˚ E
and 74.728˚ E longitude and 14.87˚ N and 13.2608˚ N
latitude was used for the study. IRS-1D and IRS-P6 are
two among the series of Indian Remote Sensing satellites.
Characteristics of both IRS-1D and IRS-P6 satellites are
presented in Table 2.
2.2. Data Processing
Topomaps were scanned and opened in ERADAS IMAG-
INE 8.5 environment. Base maps were generated based
on the Survey of India topographical maps surveyed in
the year of 1973 for Kundapur, 197 7 for Malpe, 198 0 for
Honnavar and 1981 for Karwar, registered by giving
corner points after projecting into geographic projection
with Modified Everest as the datum. IRS (LISS-III) im-
ageries of 1998 and 2008 were Geo-registered with the
base map using more than 25 corresponding Ground Con-
trol Points (GCPs) like bridges, road crossing and other
permanent significant features, using survey of India to-
posheets [11 ] .
Geo-registration is a process of stabilizing the relation-
ship between map and the known real world coordinates.
Re-sampling in each case was performed using cubic
interpolation technique to keep the spatial distortions at
minimum. Accuracy of the geo-correction is tested by
swiping one image above the other and confirmed by
field check. The geocorrected data is entered to the
ArcGIS environment for digitization of shoreline. High
waterline shown in the satellite imageries (1998 and
2008) and topographic sheets for all the four stations are
digitized as line feature. Shorelines representing different
years of a same station are presented by overlaying to-
gether. Quantification of erosion/accretion rate is done
by digitization as polygon features using ArcGIS.
Coastal process are not uniform with respect to time
and it is difficult to compare two scenes taken at differ-
ent time because of the non-uniform tides of coastal area
i.e., if it is low tide in one scene, it may be high tide in
other one. So there is chance of error in estimation of
erosion/accretion [10]. For minimizing the error, the data
during similar tidal phase is considered in the present
Geomorphologic features like alluvial plain, tidal flat,
sandbar, spit, rocky beaches and Channel Island are de-
noted on the imageries and plotted as geomorphologic
maps for each station in different years.
3. Results and Discussion
The quantitative estimation of morphological changes
along the shoreline and estuarine mouth of Karwar, Hon-
navar, Kundapur and Malpe are discussed below. The tide
variation between the satellite imageries of 1998 and 2008
for the path/row-096-062 (Karwar and Honnavar) is negli-
gible but path/row 097-063 (Kundapur and Malpe) shows
65 cm change in the tide between two data.
Table 2. Satellite data characteristics.
SatelliteSensorsSpectral bands(Microns) Resolution (m)
PAN 0.50 - 0.75 5.2 to 5.8
0.52 - 0.59 (B2),
0.62 - 0.68 (B3),
0.77 - 0.86 (B4),
1.55 - 1.70 (B5)
21.2 to 23.5
(V & IR)
WiFS 0.62 - 0.68 (Visible) 169 to 188
LISS-IV 0.52 - 0.59 (Green (Band 2)
0.62 - 0.68 (Red (Ban d 3))
0.76 - 0.86 (NIR (Band 4)) 5.8
0.52 - 0.59 (B2),
0.62 - 0.68 (B3),
0.77 - 0.86 (B4),
1.55 - 1.70 (B5)
(V & IR)
0.52 - 0.59,
0.62 - 0.68,
0.77 - 0.86,
1.55 - 1.70
Copyright © 2011 SciRes. IJG
The erosion and accretion map of Karwar during the
period of 1981 to 1998 (Figure 2) shows considerable
erosion of around 1.459 Km2 at the northern side of the
Kali River along the shoreline. Net erosion during this
period is 0.467 Km2 and net accretion is 0.29 0 Km2. The
width of the river mouth has increased from 250 to 800
m without any significant change in the position of the
river mouth, this is because of the erosion took place at the
both banks of the river mouth. During th e per iod from 1998
to 2008, at Karwar, erosion has occurred along the shore-
line from the river mouth to the northern side to a length
of around 3.75 Km (Figure 2). It is also observed that
the Kali River mouth has shifted slightly around 125 m
towards north, with net erosion of 0.397 Km2 and accre-
tion of 0.102 K m2 occurred during this period. The study
indicates that an area of 0.405 Km2 was eroded during
the last 27 years (1981-2008) from the spit mouth, which
is the most vulnerable location at station 1.
The Sharavathi River mouth has shifted significantly
(almost 1220 m) towards north during the period be-
tween 1980 and 1998 (Figure 3). Northern side of the
river mouth is affected by erosion and the southern side
shows accretion. Net erosion and accretion of the station
2 (Honnavar) is 0.465 Km2 and 0.631 Km2 respectively.
Most of the shoreline which lies along the southern part
of the river mouth shows accretion. The width of the
river mouth at Honnavar increased from 125 to 600 m
during the ten year period from 1998 to 2008 because of
the erosion at both edge of river mouth. Sediments from
the tip of the spit on the southern side of river mouth,
around 0.184 Km2 areas washed off by erosion. Net ero-
sion and accretion are measured as 0.383 Km2 and 0.770
Km2. Study shows that during the last ten years (1998 -
2008) comparatively erosion is more than the accretion.
Pavinkurve beach near the Basavarajadurg Island shows
considerable ero sion of 0.107 Km2.
Erosion and accretion map of Kundapur during 1973
to 1998, shows that river mouth has shifted around 270
m towards south (Figure 4). Erosion observed on the
southern side of river mouth for almost 1.146 Km along
the shoreline.Net erosion and accretion of the area is
0.170 Km2 and 0.326 Km2 respectively. River mouth
width decreased from 200 to 100 m. Almost 2614 m
along the shoreline of Gangoli beach grows seaward due
to accretion. The width of the river mouth is considera-
bly varying from 200 to 360 m during the last ten years
from 1998 to 2008 because of the erosion of both side of
the river mouth. An area 0.108 Km2 of the entire shore-
line of the station 3 got eroded. The net accretion of the
area is around 0.127 Km2.
Figure 2. Erosion/accretion at Karwar during 1981-1998 and during 1998-2008.
Copyright © 2011 SciRes. IJG
Figure 3. Erosion/accretion at Honnavar during 1979-1998 and during 1998-2008.
Figure 4. Erosion/accretion at Kundapur during 1973 - 1998 and during 1998 – 2008.
Copyright © 2011 SciRes. IJG
Morphological changes near the Udyavara river estu-
ary during the period from 1977 to 1998 (Figure 5)
shows that width of the mouth has been decreased due to
accretion on both sides of the river mouth from 200 to
100 m. The tip of the barrier spit lies on the southern side
of the river mouth grows gradually towards north-west
direction, dur ing 1977 to 1998 it ha s grow n aroun d 0.10 4
Km2. Net erosion and accretion of the area is 0.615 Km2
and 0.192 Km2 respectively. Study shows that, shoreline
erosion is occurring along the locations at Tenkadiyur
and Pangala to an extent of 1.372 and 4.636 Km respect-
tively. During 1977 to 1998 an area of 0.113 and 0.368
Km2 were eroded from Tenkadiyur and Pangala respec-
During 1998 to 2008, the width of the river mouth at
Malpe reduced marginally from 260 to 224 m. The tip of
the barrier spit continued to grow towards north-west,
both side of the river mouth shows accretion. Only on the
southern side of the river mouth, the spit got deposited
around 0.0 35 Km2. Study indicates that very small area is
affected by erosio n and most of the beach showed depo-
sitional characteristics. Net erosion of the area is 0.026
Km2 and the net accretion of the area is 0.355 Km2. GIS
and Remote Sensing approach study have been done by
Dwarakish et al. [12] along the Malpe coastal region.
Karwar (1981-2008): The quantity measurement of
the area covered by each geomorphology classes such as
tidal flat, spit, Marine Island, sandy beach, creek, coastal
plain, Channel Island and alluvial plain. Spit shows grad-
ual decrease in the area. Among the various land form
features spit shows the gradual decrease in area, 0.214
Km² area got eroded from the mouth of the river Kali
(Table 3). Slight increase observed in the area of coastal
plain and alluvial plain. Creek has lost 1.028 Km².
Figure 5. Erosion/accretion at Malpe during 1977-1998 and during 1998-2008.
Table 3. Geomorphologic changes at Karwar.
Class Area (Km² )
1981 Area (Km² )
1998 Area (Km² )
2008 Change in area (Km2)
1981-1998 Change in area (Km2)
tidal flat 3.397 4.333 4.272 0.936 –0.061
spit 0.814 0.729 0.601 –0.085 –0.128
marine island 0.187 0.187 0.187 0 0
sandy beach 0.505 0.622 0.513 0.117 –0.109
creek 2.490 1.959 1.462 –0.531 –0.497
coastal plain 0.694 0.707 0.771 0.013 0.064
channel island 0.165 0.242 0.261 0.077 0.019
alluvial plain 16.187 16.389 17.091 0.202 0.702
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Honnavar (1980-2008): In the case of tidal flat, it is
observed that 1.189 Km² area got reduced during the
period 1980 to 1998 and an area of 0.542 Km² increased
during 1998 to 2008.The spit which lies on the southern
side of the Sharavathi river grows 0.370 Km² towards
north (Table 4). Geomorphology of this area shows the
presence and gradual decrease in the area of sand bars
and creek. Marine Island and Lateritic plain do not show
any observable change at the location. Coastal plain co-
vers the maximum area of Honnavar region, coastal plain
increase the area from 1980 to 1998 and after that it shows
decreasing trend. In the case of Ch annel Is lan d, it is show -
ing an increasing trend in area from 1980 to 2008.
Kundapur (1973-2008): Rocky beach, sand bar and allu-
vial plane are the characteristics of Kundapur morphology.
The area which covered by the tidal flat, decreased dur-
ing 1973 to 1998 bu t 0.967 Km² area added during 1998
to 2008. Sand bar diminishes by an area of 0.227 Km²
from 1973 to 1998, but after that it shows increasing
trend from 1998 to 2008 (Table 5). No change can be
detected in rocky beaches, marine Island and alluvial
plain. It is detected that the coastal plain and channel
Island gradually increases its area during 1973 to 1998.
From 1998 to 2008, coastal plain area increased by 0.159
Km², but Channel Island shows a slight reduction in area
from 1998 to 2008. Jayappa et al., [13] studied the area
through remote sensing.
Malpe (1977-2008): It is noticed that most of the
study area of Malpe is covered by coastal plain, it shows
some changes in the area too. Barrier spit on the southern
side of the river mouth detected as increasing during
1998 to 2008 and decrease in area of 0.190 Km2 from
1977 to 1998 (Table 6). Area covered by creek reduced
during the study period. Overall sand bar quantity in-
creased during the study period. It is observed that the
Channel Island of 0.055 Km² diminished.
Table 4. Geomorphologic changes at honnavar.
Class Area Km²
1979 Area Km²
1998 Area Km²
2008 Change in area Km2
1979-1998 Change in area Km2
tidal flat 2.085 0.896 1.438 –1.189 0.542
spit 1.515 1.886 1.819 0.371 –0.067
sandy beach 0.955 0.945 1.020 –0.01 0.075
sand bar 0.023 0.083 0.040 0.060 –0.043
marine island 0.202 0.164 0.166 –0.038 0.002
lateritic plain 16.956 16.956 16.956 0 0
creek 1.135 0.592 0.576 –0.543 –0.016
coastal plain 11.728 12.004 11.325 0.276 –0.679
channel island 0.995 1.166 1.272 0.171 0.106
Table 5. Geomorphologic changes at Kundapu r a.
Class Area (Km²)
1973 Area (Km²)
1998 Area (Km²)
2008 Change in area (Km2)
1979-1998 Change in area (Km2)
tidal flat 2.581 2.050 3.018 –0.531 0.968
sand bar 0.296 0.069 1.083 –0.227 1.014
sandy beach 0.637 0.703 0.676 0.066 –0.027
rocky beach 0.027 0.027 0.027 0 0
marine island 0.052 0.052 0.052 0 0
lateritic plain 2.805 2.805 2.805 0 0
coastal plain 10.363 10.823 11.018 0.460 0.195
channel island 3.512 4.140 4.105 0.628 –0.035
alluvial plain 0.743 0.743 0.743 0 0
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Table 6. Geomorphologic changes at malpe.
Class Area (Km²)
1977 Area (Km²)
1998 Area Km²
2008 Change in area Km2
1979-1998 Change in area Km2
sandy beach 1.123 0.978 1.267 –0.145 0.289
sand bar 0.307 0.204 0.362 –0.103 0.158
marine island 0.555 0.555 0.555 0 0
creek 0.689 0.420 0.320 –0.269 –0.100
coastal plain 23.318 23.168 23.440 –0.150 0.272
channel island 0.340 0.246 0.285 –0.094 0.039
barrier spit 1.002 0.812 0.938 –0.190 0.126
4. Conclusions
This study investigates the coastal erosion and depo sition
at four stations (Karwar, Ho n navar, Kundapur, and M a l pe)
covering a period of almost thirty years along the Karna-
taka, west coast of Ind ia. Both erosion and depo sition are
observed at all the four stations. The erosion observed is
not continuous all along the coast but in isolated stretches
along the coast. Comparatively large erosion have been
observed at the river mouths of Devbag (north of Kali
River), at Pavinakurve (north of Sharavathi River) and at
Kundapur. The coastline at Malpe is almost stable with
negligible erosion and deposition. Significant amount of
loss of land is observed mainly at the river mouth due to
the sediment erosion from the banks because of complex
interactions between river flow, waves and the tides.
5. Acknowledgements
We thank Integrated Coastal and Marine Area Manage-
ment Project Directorate (ICMAM PD), Ministry of Earth
Sciences, New Delhi for funding the project. Director,
National Institute of Oceanography, Goa and Project Di-
rector, ICMAM PD, Chennai for the encouragement pro-
vided to carry out the study. This is NIO contribution
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