Shoreline Change Assessment for Odisha Coast This computer-generated perspective view of the Odisha coast highlights the locations of major ecological and deltaic systems along this coast. The image shows “Chilika Lake” (shown in blue) the largest brackish water lagoon in India, Mahanadi delta, the second largest delta in India and the Bhitarkanika Mangroves. This image combines offshore bathymetric data of GEBCO and SRTM ASTER Digital-Elevation data. The coastline of India is not restricted by administrative borders, varying degrees. Erosion, transport, and undergoing changes due and constantly change in response to the accretion that results are continuous to various anthropogenic wind, waves, tides, sea level fluctuation, and interrelated processes. and natural interventions. seasonal and climatic variation, human Most of the shoreline alteration, and other factors that Shorelines also change seasonally, changes are on account of influence the movement of sand and tending to accrete slowly during the the structures which have been developed/ material within a shoreline system. The summer months when sediments are constructed along the foreshore of the country. Several of these developments are loss (erosion) and gain (accretion) of deposited by relatively low energy not compatible with the dynamic nature coastal land is a visible result of the way waves and erode dramatically during of the shoreline. Because of these factors, shorelines are reshaped in the face of the winter when sediments are moved it has become imperative to identify areas these dynamic conditions. offshore by high energy storm waves. subject to both long- and short-term erosion, In addition, attempting to halt natural since in most cases, rates of erosion have How and Why Shorelines Change? coastal process with seawalls and enhanced during the past decade. The Ministry of Environment and Forests is As the waves gently lap the shore of a other hard structures, only shifts the mapping the coastline to enhance the sandy beach, do you ever wonder where problem, subjecting downdrift coastal country’s preparedness to face sea hazards that sand came from? areas to similar losses. Also, without like storm surge and Tsunami. The answer is: “erosion” the sediment transport, some of the The source of the sand that created and beaches, dunes, barrier beaches, salt The National Assessment of Shoreline continues to feed the beaches, dunes, marshes, and estuaries—are threatened Change for Gujarat and Puducherry has been released by the Honourable Union and barrier beaches in India, comes and would disappear as the sand primarily from the erosion of coastal sources that feed and sustain them are Minister Shri. Jairam Ramesh, Minister of State for Environment and landforms. All sedimentary coasts tend eliminated. Forests, on 29th December 2010. Today, the to erode at one time or another and this 29th April 2011, the shoreline change maps basic tenet of coastal science, reflects As populations continue to grow for Odisha is being released and major the complex interactions that occur and community infrastructures are highlights are provided in this factsheet. at the land-ocean interface. Wherever threatened by coastal erosion, there shorelines are composed of discrete is increased demand for accurate Coastal erosion is a chronic problem grains of sediment, the processes of information regarding past and present and is often thought of as inevitable winds, waves, currents and changing trends and rates of shoreline movement. along most open shores of the country. water levels combine to mobilize There is also a need for a comprehensive Shorelines and coastal processes are particles and move them around by analysis of shoreline movement that is National Centre for Sustainable Coastal Management (NCSCM) Society of Integrated Coastal Management (SICOM) Ministry of Environment and Forests (MoEF), Government of India General Facts and Figures consistent from one coastal region to The historical shorelines represent the another. Prediction of shoreline retreat following periods: 1972 (Survey of India Latitude 17°49' N and 22°34' N and land loss rates is critical to planning toposheet) used as base map, satellite Longitude 81°27' E and 87°24' E future coastal management strategies. imageries of 1990, 2000, and 2010. For Area 156,000 km2 To date, long-term planning for India’s the coast of Odisha, base maps were Odisha State 36.7 million (2001 prepared on 1:50,000 scale using the Population census) shoreline has been done in piecemeal, if toposheet of the Survey of India. Onscreen Population Density 236 persons/km2 at all. Consequently, entire communities digitization of coastline was made using (2001 census) are being developed without adequate various satellite imageries on 1:50,000 Length of 480.40 consideration of the potential costs of scale and stored as different layers in GIS Coastline (km) erosion, flooding, and storm damage environment for the years 1990, 2000, Coastal Districts of Odisha related to sea-level rise. Ganjam 60.85 and 2010. Depending on location and data source, different proxies for shoreline Puri 136.48 In order to correctly interpret shoreline Jagatsinghpur 58.95 position were used to document coastal change, all shoreline data were analyzed Kendrapara 83.55 change, including high water line, wet-dry Bhadrak 52.61 and evaluated in light of current line, vegetation line, dune toe or crest, toe Baleshwar 87.96 shoreline conditions, recent changes or berm of the beach, cliff base or top, and Population in 8,975,581 in shoreline uses, and the affects of the instantaneous water line as extracted Coastal Districts human-induced alterations to natural from satellite imagery. Area of Coastal 21,887 km2 shoreline movements. In areas that show Districts shoreline change reversals (i.e., where These multi-date shorelines served as Population Density 410 persons/km2 (2001 the shoreline fluctuates between erosion input into the USGS Digital Shoreline in Coastal Districts census) and accretion) or areas that have been Analysis System (‘DSAS’) software to Major Ecological Chilika Lagoon extensively altered by human activities, cast various transects along the coast of Systems (672 km2) Odisha. A distance of 300m intervals from Bhitarkanika wildlife knowledge of natural and human the baseline was assigned to calculate the sanctuary impacts are typically required for proper Gahirmatha and interpretation. erosion/ accretion statistics in ArcGIS Rushikulya Olive Ridley 9.3 software. The results obtained were Nesting Sites The coastline of the state of Odisha is categorized into eight classes of “Zones of Rivers of Odisha ~480km long and consists of six coastal erosion/ accretion” as follows: District Rivers districts. The southern tip of the Odisha Ganjam Bahuda coast borders the state of Andhra Pradesh Rushikulya and the northern end connects to the state Puri Chilika Lake mouth of West Bengal. Mangala Nadi Bhargavi Nadi Shoreline Change Assessment of Odisha Kushabadra Nadi Prachi/Kadua Nadi Shorelines are subjected to dynamic Jagatsinghpur Devi River changes due to coastal processes, that Balijhori Nadi are controlled by wave characteristics Bitikolia Nadi and the resultant near-shore circulation, JatadharMohan Nadi sediment dynamics, beach form, etc. Mahanadi River For the rates reported herein, erosional Kendrapara Hansua Nadi trends are presented as “negative” values Bansgarh Nadi and accretional trends are presented as Maipura Nadi “positive” values. Coastal erosion is Of the zones on which the shoreline was Bhadrak Dhamra Nadi considered as more vulnerable because of eroding, ‘high erosion’ was observed at Gamai Nadi the resultant loss of coastal infrastructure north of river mouths along the Odisha Baleshwar Kantiachara Nadi and important natural habitats such as coast. High erosion was also observed Nunia Nadi beaches, dunes, and mangroves. It also on the southern part of the breakwaters Kamachara Nadi reduces the distance between coastal of ports, where such coastal engineering Khandita Nadi population and ocean, thereby increasing structures have greatly altered the natural Burhabalang River the risk of exposure of population to shoreline movement. Presence of major Panchpara Nadi coastal hazards. mangrove systems at the Mahanadi delta Hanskara Nadi and the Bhitarkanika Mangrove Forest Subarnareka River The shoreline change assessment of have resulted in ‘high accretion’ areas Ports of Odisha Odisha Coast represents long-term along the Odisha coast. District Ports shoreline change for a period of 38 Ganjam Gopalpur years from 1972-2010. Shoreline change Seawalls and/or riprap revetments have Palur Fishing Harbour evaluations are based on comparing been constructed in as much as 9.78 Puri Astaranga four historical shorelines extracted from km of the coastal stretch of Odisha to Jagatsinghpur Paradip satellite imageries for the above time protect coastal infrastructure from erosion Kendrapara Nil period, with recent shoreline derived from and these areas have been classified as Bhadrak Dhamra LISS III images and limited field surveys. Baleshwar Anantpur ‘Artificial Coast’. Statistics indicate that National Centre for Sustainable Coastal Management (NCSCM) Society of Integrated Coastal Management (SICOM) Ministry of Environment and Forests (MoEF), Government of India Table 1: Shoreline Characteristics and Statistics for Odisha Coast Classification of Coast Extent (km) % of Coast Cumulative (%) Total length of coastline 480.40 High Erosion Zone 39.33 8.19 Medium