Sasthamcotta Lake or Sasthamkotta Lake, also categorized as a wetland, is the largest fresh water lake in

Kerala Kerala ( , ) is a States and union territories of India, state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile ...

, a state of

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

on the south of the West Coast. The lake is named after the ancient Sastha temple (a pilgrimage centre) located on its bank. It meets the drinking water needs of half million people of the

Quilon Kollam (;), is an ancient seaport and the fourth largest city in the Indian state of Kerala. Located on the southern tip of the Malabar Coast of the Arabian Sea, the city is on the banks of Ashtamudi Lake and is 71 kilometers (44 mi) nort ...

district and also provides fishing resources. The purity of the lake water for drinking use is attributed to the presence of large population of larva called ''cavaborus'' that consumes

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

in the lake water. The lake is a designated wetland of international importance under the

Ramsar Convention The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on We ...

since November 2002.

Access

The lake is located at a distance of 25 km from

city, which is on the northern side of

Ashtamudi Lake Ashtamudi Lake (''Ashtamudi Kayal, ml: "അഷ്ടമുടിക്കായൽ" ''), in the Kollam District of the Indian state of Kerala is a unique wetland ecosystem and a large palm-shaped (also described as octopus-shaped) water body. ...

Thiruvananthapuram Thiruvananthapuram ( ), also known as Trivandrum, is the Capital city, capital city of the Indian state of Kerala. As of 2011, the Thiruvananthapuram Municipal Corporation had a population of 957,730 over an area of 214.86 sq. km, making it the ...

International Airport, at 105 km, is the nearest airport to Kollam. Karunagapally, at a distance of 8 km, is the closest town to the lake. A ferry service across the lake transports people between West Kallada and Sasthamkotta.

Topography and geology

Except for an earthen embankment of 1.5 km length which separates the lake from the paddy fields on its southern side, bordering the alluvial plains of the Kallada River, all other sides of the lake are surrounded by hills which are steep and form narrow valleys. In the south and southwestern parts of the lake there are a number of smaller water bodies and waterlogged areas. The present area of the lake is 375 ha since large part of the lake is reported to have been occupied for agriculture. Rock formation of mainly archaean origin are recorded with intrusions of

charnockite Charnockite () is any orthopyroxene-bearing quartz-feldspar rock formed at high temperature and pressure, commonly found in granulite facies’ metamorphic regions, ''sensu stricto'' as an endmember of the charnockite series. Charnockite seri ...

, biotite

gneiss Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under p ...

and

dolerite Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grain ...

dyke rocks. The

Tertiary Tertiary (from Latin, meaning 'third' or 'of the third degree/order..') may refer to: * Tertiary period, an obsolete geologic period spanning from 66 to 2.6 million years ago * Tertiary (chemistry), a term describing bonding patterns in organic ch ...

Varkala formations are observed along the coastal beds. In the valley portion, sand and silt deposits are recorded.

Geomorphological Geomorphology () is the scientific study of the origin and evolution of topography, topographic and bathymetry, bathymetric features generated by physical, chemical or biological processes operating at or near Earth#Surface, Earth's surface. Ge ...

divisions of the basin area of the lake comprise a) the undulating uplands which have fairly thick vegetation of mixed crops and plantations, b) the valley fills of

laterite Laterite is a soil type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by intensive and prolo ...

alluvium Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...

and colluvial deposits with low level areas which are intensely cultivated and thickly populated and c) the flood plains/alluvial plains of the Kallada River on the south that are mostly cultivated.

Hydrology

There are no visible tributaries feeding the lake but springs at the bottom of the lake are stated to be one of the source which supply water throughout the year; volume of water in the lake is estimated to be of the order of 22.4 million cum. A thick 10–20 m mantle of

kaolinite Kaolinite ( ; also called kaolin) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedral sheet of alumina () ...

rich (derivative of laterite) soil around the lake is stated to check flow into the lake and the theory is now that the lake is also rain fed; the lake water level is recorded to be higher at the end of the monsoon season. The average annual rainfall in the area is 2398 mm and mean annual temperature varies between 26.7 °C and 29.16 °C. Ground water table in the area is reported at depth of 3.89 m. After accounting for estimated evaporation loss of 5 MCM (

million cubic metre The cubic metre (in Commonwealth English and international spelling as used by the International Bureau of Weights and Measures) or cubic meter (in American English) is the unit of volume in the International System of Units (SI). Its symbol is m ...

s) and water utilized for domestic use of 8 MCM (at a pumpage rate of 22 MLD), the two together account for about two-thirds of the inflow.

Water quality

The lake water is reported to be free of common salt or other

minerals In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): M ...

and

metals A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. These properties are all associated with having electrons available at the Fermi level, as against no ...

. The quality for

surface water Surface water is water located on top of land, forming terrestrial (surrounding by land on all sides) waterbodies, and may also be referred to as ''blue water'', opposed to the seawater and waterbodies like the ocean. The vast majority of surfac ...

, interstitial water and

sediments Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

studied by World Wildlife Fund (WWF), India are briefly as noted below. Quality for surface water (average values): * Surface water: pH 7.25; EC 63.00 Millimhos/cm; PO₄ – P 4.93 Micro gm. / l ; Ca 7.01Micro gm. / l; Na 4.33 Micro gm. / l; Fe 41.57 Micro gm. / l and Mn 12.11 Micro gm. / l. * Interstitial water: pH 7.20; PO₄ – P 1.11 Micro gm. / l; Fe 59.1Micro gm. / l and Mn49.00 Micro gm. / l * Sediments: Organic C 8.95%; PO₄ – P 1690.00 Micro gm. / l; Fe 17724.27 Micro gm. / l and Mn 86.36 Micro gm. /l Water quality test results indicate that the lake water conforms to standards of drinking water prescribed by regulatory bodies.

Flora

Eastern shore of the lake has the insectivorous plant

Drosera ''Drosera'', which is commonly known as the sundews, is one of the largest genus, genera of carnivorous plants, with at least 194 species. 2 volumes. These members of the family Droseraceae lure, capture, and digest insects using stalked mucil ...

Sp. Vegetation is negligible and rooted plants and floating plants are unimportant and insignificant. The crops grown on the banks of the lake, apart from paddy, are the plantation crops such as cashewnut,

tapioca Tapioca (; ) is a starch extracted from the tubers of the cassava plant (''Manihot esculenta,'' also known as manioc), a species native to the North Region, Brazil, North and Northeast Region, Brazil, Northeast regions of Brazil, but which has ...

and plantain.

Aqua fauna

The aqua fauna noted in the lake are: * 27 species of freshwater fishes include pearl spot ( Etroplus suratensis) and

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

, two genera of

prawns Prawn is a common name for small aquatic crustaceans with an exoskeleton and ten legs (members of the order of decapods), some of which are edible. The term ''prawn''Mortenson, Philip B (2010''This is not a weasel: a close look at nature's most ...

, 21 species of

herring Herring are various species of forage fish, belonging to the Order (biology), order Clupeiformes. Herring often move in large Shoaling and schooling, schools around fishing banks and near the coast, found particularly in shallow, temperate wate ...

s and

sardines Sardine and pilchard are common names for various species of small, oily forage fish in the herring suborder Clupeoidei. The term "sardine" was first used in English during the early 15th century; a somewhat dubious etymology says it come ...

of the family

Clupeidae Clupeidae is a family of clupeiform ray-finned fishes, comprising, for instance, the herrings and sprats. Many members of the family have a body protected with shiny cycloid (very smooth and uniform) scales, a single dorsal fin, and a fusiform ...

* Common

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

such as ''Calichrous bimaculatus'' and ''

Wallago attu ''Wallago attu'', boal, or helicopter catfish, is a species of freshwater catfish of the family Siluridae, native to South and Southeast Asia. ''W. attu'' is found in large rivers and lakes in two geographically disconnected regions (disjunct di ...

'' These varieties of fish generally have whisker-like barbells set around their mouths. The common teal or

dabbling duck The Anatinae are a subfamily of the family Anatidae (swans, geese and ducks). Its surviving members are the dabbling ducks, which feed mainly at the surface rather than by diving. The other members of the Anatinae are the extinct moa-nalo, a y ...

is the smallest migratory bird found in the lake. Some of the vulnerable, endangered and critically endangered species reported by WWF in the lake area are: * Critically endangered: '' Puntius ticto punctatus'' (Day) * Endangered: '' Horabagrus brachysoma'' (Gunther) * Vulnerable: '' Parambassis thomassi'' (Day)

Fauna

Resident troops of

monkeys Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes. Thus monkeys, in that sense, co ...

are sighted on the banks in large numbers, which are part of the Sasthamkotta temple environment on the bank of the lake. 13 species of insects have also been identified; 9 are

butterflies Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...

, 2 odonates and 2

hymenopteran Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typi ...

Deterioration in lake environment

The quality of the lake environment is affected by the following factors. * Increasing

anthropogenic Anthropogenic ("human" + "generating") is an adjective that may refer to: * Anthropogeny, the study of the origins of humanity Anthropogenic may also refer to things that have been generated by humans, as follows: * Human impact on the enviro ...

pressure * Encroachment on parts of the lake for agriculture * Cultivation of tapioca has increased the soil loss by

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

and runoff into the lake basin * Domestic and agrochemical wastes from surrounding areas disposed into the lake * Soil erosion of the banks from the encroached land * Effluents from domestic sewage * Reduction of ground water recharge to the lake due to increase in

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

in the area around the lake. * Soaking of dry leaves of

coconut palm The coconut tree (''Cocos nucifera'') is a member of the palm tree family (biology), family (Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, ...

before matting, which are then used for thatching huts

Conservation and management

The Kerala State Government prepared a Conservation and Management Action Plan (MAP) in 1999 for the lake's sustainable utilization and conservation and to address the threats faced by the lake. Financial support was sought from the Central Government under the National Lake Conservation Plan (NLCP) for implementation of MAP based on the specific problems identified in the wetland. The MAP envisages the following activities: * Agro-forestry in the catchment, *

sanitation Sanitation refers to public health conditions related to clean drinking water and treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation systems ...

and drainage, *

pollution Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...

abatement, * limited desilting, *

weed A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

control, * conservation of

flora Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...

and

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

, *

fishery Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish far ...

development, and * awareness campaigns among the local inhabitants. The above activities were planned to be implemented through the Kerala Water Authority (KWA), Department of Forests and Wild Life, Department of Fisheries, State Fisheries Resource Management Society (FIRMA), District Rural Development Agency (DRDA), CWRDM, etc. Kerala State Council for Science Technology and Environment of Govt. of Kerala provided the support and overall supervision.

Gallery

File:Sasthamcotta Lake 1 by ArunElectra.jpg, Sasthamkotta Lake File:Sasthamcotta Lake 2 by ArunElectra.jpg, Sasthamkotta Lake File:Sasthamcotta Lake Sunset by ArunElectra.jpg, An Evening view of Sasthamkotta Lake File:Keralaback (15).jpg, Village on bank of the lake

References

External links

GeoHack - Sasthamcotta Lake
* {{Ramsar sites in India Lakes of Kollam Ramsar sites in India Tourist attractions in Kollam district Geography of Kollam district Wetlands in Kollam district