Үндістанның шалап көлі: геологиялық және гидрологиялық ерекшеліктері

Lagoon in India

| reference = It has been listed as a tentative UNESCO World Heritage site. Its salinity varies by region, from freshwater where rivers flow in, to oceanic salinity levels due to tidal influx.

The lake is of estuarine character in an ephemeral environment. Geological studies indicate that the coastline extended along the western shores of the lake in the Pleistocene era with its northeastern region lying under the sea. That the coastline has moved eastward over the ages is supported by the fact that the nearby Konarak Sun Temple, built originally on the seashore a few hundred years ago, is now about , away from the coast. The catchment area of Chilika lake has a rock, sand and mud substratum. It contains a wide range of sedimentary particles such as clay, silt, sand, gravel and shell banks but the major part of the catchment area is silt. Around 1.6 million metric tons per year of sediment is deposited in Chilika lake by rivers Daya and several streams.

Chilika Lake is a shallow bar built estuary with large areas of mudflats. The western and southern margins of the lake are fringed by the Eastern Ghats hill range. formed by northerly currents in the Bay of Bengal, resulted in the formation of this shallow lake and forms its eastern side. As an ephemeral lake, its water surface area varies from in the summer monsoon season to in the winter dry season. The water spread area of the lagoon ranges between during the monsoon and summer respectively. A long, narrow, outer channel connects the lagoon to the Bay of Bengal, near the village Motto. More recently a new mouth has been opened by Chilika Development Authority (CDA) which has brought a new lease of life to the lagoon. The lake has numerous islands. The larger islands, separated by shallow channels, lie between the barrier and the main body of the lake. A total of channels connect the lake with Bay of Bengal. The north shore of the lake is part of Khordha District and the western shore is part of Ganjam District. Due to siltation, the width of the barrier has fluctuated and the mouth to the sea has periodically been closed. The location of the mouth has also frequently shifted, generally towards the northeast. The mouth, which was wide in 1780, was only forty years later. The local fishermen, to maintain their livelihood, had to cut open the mouth to gain access to the sea for fishing. is the longest lake (if the length is considered, where the length of Chilika Lake is ) in India.

Three hydrological subsystems control the Hydrology of the lake. The land based system comprises distributaries of the Mahanadi River on the northern side, 52 river channels from the western side and the Bay of Bengal on the eastern side. Two of the three southern branches of the Mahanadi River that trifurcates at Cuttack, feed the lake. 61% of the total freshwater inflow into the lake is contributed by these two branches. The second drainage system which is non–perennial accounts for 39% The important rivers of this drainage system are the Kansari, the Kusumi, the Janjira, and the Tarimi rivers. The annual total surface freshwater input to the lake is estimated to including direct precipitation over the lake contributing
All the inland river systems disgorge an annual flow of about of freshwater which is estimated to carry 13 million metric tons of silt into the lake. On the northeast, a channel connects the lake to the Bay of Bengal. A tropical monsoon climate prevails over the drainage basin area of the lake. The lake experiences South–west and North east monsoons during June to September and November to December respectively with an average annual rainfall of , with 72 rainy days. The maximum temperature of 39.9 °C (104 °F) and minimum temperature of 14 °C (57 °F) have been recorded

The Chilika Development Authority (CDA) established an organized system of water quality measurements and limnological investigations indicating the following physico–chemical characteristics of the lake waters. Sediment cores were collected from different locations of the lake. The result indicated spatial variation of sedimentation rate in three zones of the lake of /year (Northern Sector), /year (Central Sector) and /year (Southern Sector). The non–uniform sedimentation rate along with the porosity and water content of the sediment cores were also analysed which indicated the lake had different deposition zones, with comparatively higher sedimentation rate in Northern and Central Sector and a slow rate in the Southern Sector.

The ecological richness of the lake is of value in preserving the genetic diversity because of the multiplicity of its habitat, flora and fauna (see photo gallery).

The 15 km2 Nalaban Island is within the Lagoon and is the core area of the Ramsar designated wetlands. It was declared a bird sanctuary under the Wildlife Protection Act in 1973. It is the heart of the park where one can see thousands of birds descending during the migratory season. The island disappears during monsoon season due to inundation, and post monsoon, the island emerges again. The lake harbours 225 species of fish, a variety of phytoplankton, algae and aquatic plants, and also supports over 350 species of non aquatic plants. The other areas where high concentrations of birds are recorded are Gerasara, Parikud Island, and the western shores of the northern sector.

Recently Chilika Lake has gathered a reputation to be a tourist trap where a number of individuals run pearl and gemstone scams. Chilika Lake gemstone scam in India

The lake is connected by road to Chennai and Kolkata through National Highway No 16. Satpada town on the eastern bank of the lake is about by road southwest of the city of Puri and at a distance of from Bhubaneswar, the capital of Odisha, which is also the nearest airport. A broad gauge railway line of the South Eastern Railway from Kolkata skirts along the western bank of the lake passing through Balugaon, Chilika and Rambha stations. There are OTDC Guest houses at Barkul, Rambha, Satapada & several hotels at Balugaon. Before entering into the Nalbana Bird Sanctuary one has to obtain an entry permit. The entry permit has to be produced at entry/exit points, at check gates as and whenever requested by officials.

Akanksha Damini Joshi's film, Chilika Bank$ (2008) tells the story via a banyan tree on the banks of lake Chilika tracing the ecological changes in the lake over four decades. From 1970s, when it was exposed to poaching by the outsiders, through 1980s when the lake was over fished, to 1990s when the aqua culture ponds became a common sight, and finally the first decade of the 21st century when the environmental interference that was made to protect the lake ended up becoming its greatest threat. Joshi's film maps the destruction of the lake and its abuse for the past four decades. The locals have been looted of their life support system with migration now being their only recourse. The film provides account of how uncontrolled human intervention has turned the lake, which was a sustainable livelihood resource, into a mere waterbody that tourists can dip their feet into. The film produced by Public Service Broadcasting Trust was honored with the Livelihood Award at the CMS Vatavaran Environment and Wildlife Film Festival, New Delhi in 2009. It was recipient of the First Prize at Jeevika, South Asia Documentary Film Festival. Chilika Bank$ was screened in the Indian Panorama section of the 40th International Film Festival of India (IFFI), Goa 2009 in the non feature film category. The film has garnered multiple television screenings on India's public broadcaster, Doordarshan's various channels. The film was an Official Selection at the Film South Asia, Kathmandu in 2009, the Rodos EcoFilms International Festival,Greece in 2010 and the 4th Samsung Women's International Film Festival, Chennai in 2011. Chilika Banks is displayed in various renowned university libraries like the Harvard University, Washington University, Duke University, Emory University and Syracuse University; and the Library of Congress, de facto the National Library of United States of America.