Morpho-dynamic evolution of Ekakula spit of Odisha coast, India using satellite data

摘要

Ekakula spit is at the northern end of Gahirmatha coast in the state of Odisha, India. This spit is located at the mouth of Maipura river, which is falling in the northern side of Mahanadi delta region. This spit is a prominent and important for many reasons because it triggers interests to the coastal managers and environmentalists because of its nature. Multi temporal satellite images (1999-2009) were used to study the Morpho-dynamic evolution of this spit. Results show that the spit grows towards northeast mainly by the deposition of sand brought by the littoral drift from the south. In the past, it got fragmented and detached portion moved away towards the offshore. Temporal satellite images revealed the progressive evolution of the spit. Spit appears to have undergone growth and fragmentation over the years and accordingly the Maipura river mouth shifted back and forth. The growth of the spit forces the river to shift its mouth and the river causes the fragmentation by breaching the spit during heavy floods. Ekakula spit lost about 306 m when compared its position in 1973 (SOI toposheet) to the satellite image of 1999. The year-wise length of the Ekakula spit was estimated using satellite data for the period 1999-2009 from a base point selected for this purpose. Ekakula spit length increased since 1999 by 2710 m by 2008 and little reduced to 2431 m during 2008-2009. Spit appears to be growing steadily by the deposition of sediment brought from south by the littoral drift except during 2003 and 2009 when it suffered some erosion. Maximum increase in length was during 2004-2005 followed by 2000-2001 and 1999-2000. Minimum was during 2004-2005. Erosion was minimal during 2002-2003.