Science & Technology

Extensive erosion of mudflats changes shoreline in Gulf of Khambhat

ISRO researchers have found that about 28.66 sq km area of high tidal mudflats was eroded in less than 4 years in Gulf of Khambhat, that is a hotspot for major development activities

 
By Ravi Mishra
Last Updated: Thursday 19 July 2018 | 11:48:00 AM

The Gulf of Khambhat is a tidal regime in the Arabian Sea formed at the mouth of major rivers Tapti, Narmada, Mahi, Sabarmati that form estuaries along the west coast. Credit: Pixabay

Tidal mudflats of Gulf of Khambhaton west coast constitute an important ecosystem on India’s coastline. Scientists have now found that these mudflats are experiencing severe erosion which is threatening the vital habitat.

Scientists from Ahmedabad-based Space Applications Centre (SAC) of Indian Space Research Organisation (ISRO) have reported extensive erosion of mudflats by studying sequential satellite images. Scientists analysed temporal satellite images to understand the hydrodynamics and coastal processes along the northern part of the Gulf of Khambhat. 

The Gulf of Khambhat is a tidal regime in the Arabian Sea formed at the mouth of major rivers Tapti, Narmada, Mahi, Sabarmati that form estuaries along the west coast.

The researchers found that a total of about 28.66 sq km area of high tidal mudflats has got eroded within a span of just three and a half years - from March 2014 to September 2017. The erosion rate was observed to be very high at 3.5 to 4 km per year, according to results of the study recently published in journal Current Science.

The erosion is higher in winter and pre-monsoon seasons than during the summer monsoon. It appears to be because of high input of fresh water during the summer monsoon, which prevents strengthening of current velocity during high tide. Although high tidal mudflats are rarely flooded even under high tide conditions, extensively high erosion has been observed along the 20 km long stretch and about 3 km inside.The high rate of erosion has changed the shoreline.

“The high erosion is due to the meandering tidal channels that connect Mahi river to the Gulf. The strong tidal current along the outer boundary of meandering river carved the channel and tidal channel migrate towards the land side” explained Ratheesh Ramakrishnan, senior scientist and research team leader, while speaking to India Science Wire.

Tidal flats or Mudflats are deposits of mud, silt and clay made by tides or rivers along a coast. They are found in sheltered areas such as bays, bayous, lagoons and estuaries and range from soft muds to firm sands. Mudflats can be categorised into three distinct zones - sub-tidal (shallow underwater deposits) zone, middle intertidal zone and upper supra-tidal zone or high tidal mudflats. The high tidal mudflats are the least inundated and are submerged only at high tide. They are usually covered with vegetation and are characterized by fine-grained deposits consisting of clay and fine silt.

Noting that the Gulf of Khambhat is a hotspot for major development activities, researchers hoped the study will help ensuring that the mudflats are saved before they are destroyed totally.

The research team included Hiren Bhatti, Ratheesh Ramakrishnan, A K Sharma and A S Rajawat. (India Science Wire)

Subscribe to Weekly Newsletter :

Related Story:

Toxic tides

Arabian Sea is suffocating due to toxic algae bloom, and it is going to get worse

Eco-sensitive regions could see flurry of construction activity as draft CRZ notification suggests

IEP Resources:

Incessant erosion of high tidal mudflats in the northern Gulf of Khambhat

Coastal morphodynamics of Tupilipalem Coast, Andhra Pradesh, southeast coast of India

Coastal infrastructure: a typology for the next century of adaptation to sea-level rise

Excessively large-scale slumping of Sajnekhali creek banks in the Sundarban delta mangrove complex: a consequence of rising sea

We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.