Geomorphological changes, such as river
system disorganization and disappearance, were noticed
on satellite imagery in northwestern India. The present
study was carried out in Mendha river catchment which displays
peculiar linear structures and abrupt changes in river
course on satellite images. Remote Sensing satellite data
also have been found very useful in the delineation of
lineaments. Thus, the IRS-1D LISS III image of 2004 and
Landsat FCC image of 1975 were used to delineate lineaments,
river course dynamics and recent geomorphological changes.
For this the visual interpretation and digital image processing
of the satellite data were performed. The regional lineaments
were also utilized to understand the tectonics of the area.
It is observed in the study that the Mendha river is structurally
controlled and shifting its course, also geomorphic features
of recent origin are identified. From these observations,
it is inferred that the catchment area is neotectonically
active.
The neotectonic activities may produce
landscape changes such as river course modifications, abrupt
swings in river courses, development of paleo/buried, abandoned
channels and playa lakes (Hirabayashi et al.,
1996; Saraf, 1998; and Goldsworthy and Jackson, 2000).
The northwestern part of India has been tectonically active
in the recent past due to the persistent movement of Indian
plate towards the Tibetan plate (Sahoo et al.,
2000). Evidences of this are: rise in the Himalayas, Siwalik
and vertical oscillations in blocks of the Aravalli hill
ranges, occurrence of earthquakes and disorganization in
the river system of northwestern India (Valdiya, 1984;
Ni, 1989; Ramasamy et al., 1991; Kumar et
al., 2001; and Wesnousky et al., 2001). For
example, the Saraswati, the mighty historical river, which
once used to flow across the northwestern part of India,
disappeared from the surface; numerous paleo-channels of
this river are present in this region (Ghose et al.,
1979; Kar and Ghose, 1984; and Gupta et al., 2004).
However, high energy river flow was noticed in northwestern
India using satellite imageries (Valdiya, 1984); he also
concluded that such mighty river could not have been merely
disappeared due to aeolian activities.
Further, Saini et al. (1989)
conducted a study on Mendha river catchment using multi-date
satellite data (Landsat 1972, 1975 MSS scenes and a TM
scene of 1986) and reported a gradual development of abandoned
channels at two locations due to sand deposits across the
Mendha river course. But they did not consider the role
of neotectonics in changing the course of river, whereas
many scholars have reported neotectonics in this region
(Ramasamy et al., 1991; and Sinha-Roy, 2001a and
2001b). |
