Ashtamudi Lake

Quilon or Kollam and inevitably Ashtamudi lake's importance is claimed to be dated to the days of the Phoenicians and the Romans. Ibn Batuta, during his 24-year sojourn in the 14th century, is reported to have mentioned about the Quilon port as one of the five ports for Chinese trade. Links with Persia (9th century), Chinese mandarin in 1275 AD, Portuguese in 1502 AD, and the Dutch followed British in 1795 AD are recorded history. Velu Thampi is credited with organizing the rebellion against the British from this place.[8]

Considering Kollam as the entry city to the lake, access to the lake are to the Thiruvananthapuram International Airport, 71 km (44 mi) away and by road to almost all important centres in Kerala and the rest of the country. National Highway 47 (NH 47) passes through the lake periphery not only from Quilon but also to other locations on its bank from Thiruvananthapuram to the northern towns of Kerala. Southern Railways network of lines connects Quilon with all important centres in the rest of the country. Ferry services operate daily to Alleppey and boats operate to all villages located in the canals of the backwater system. The boat jetty is located at about 2 km (1.2 mi) away from the railway station.[6] Famous Paravur estuary and backwaters are just 21 kilometer away from Ashtamudi.

Kallada River

Kallada River is a major river discharging into the Ashtamudi Lake. The Kallada river, which originates near Ponmudi from the Kulathupuzha hills Western Ghats is formed by the confluence of three rivers, viz., Kulathupuzha, Chenthurnipuzha, and Kalthuruthipuzha, and after traversing a distance of about 121 km (75 mi) through virgin forests finally debouches into the Ashtamudi wetland at Peringalam near Kollam. With a maximum depth of 21 ft (6.4 m) at the confluence, it is Kerala's deepest estuary.[9][10]

Quaternary and Tertiary sediments and sedimentary rocks are the formations in the lake basin and environs. The Quaternary sediments are of marine and fluvial alluvium of recent age. Tertiary sediments comprise laterite, sandstones and clays of Warkalai formation.[3]

Astamudi Lake Near Veerabhadra Swami Temple

The average annual runoff from the river system into the estuary is reported to be 76 cubic kilometers of freshwater.[10] The basin drainage area is 1,700 km² (660 mi²) and with an average annual rainfall of 2400 mm (94 in) it discharges 3.375 km³ (2,740,000 ac·ft) of flow annually. It acts as a flood storage lake thus protecting the thickly populated city of Quilon (Kollam) and the coastal land. The Kallada dam built across the Kallada river is 85.3 m high by 35 m long (280 ft by 115 ft) with a reservoir area of 23 km² (8.9 mi²) with a storage volume of 0.505 km³ (409,000 ac·ft). Though it provides irrigation to 61630 ha for paddy and upland crops, it has aggravated the salinity ingress into the wetland and the river due to reduced outflows during summer months.[3]

Temperatures recorded in the area are a maximum of 27.5 °C (81.5 °F) and a minimum of 25.5 °C (77.9 °F). The climate is hot and humid during April–May while cool during December–January.

Ashtamudi Estuary has mangroves Avicennia officinalis, Brugiera gymnorrhiza and Sonneratia caseolaris as also 43 species of marshy and mangrove associates including two endangered species Syzygium travancoricum (endangered species according to the Red Data Book of Indian Plants) and Calamus rotang in the Terrestrial system.[2] These species offer excellent scope for development of marine bioreserve to promote eco-tourism in the estuarine of the lake.[10] IUCN lists the two endangered species in IUCN 2008. The total number of Syzygium travancoricum is reported to be very small, not more than 200. The major threats to the endangered species are reportedly draining of the wet lands and conversion into paddy fields.[11]

The lake supports 57 species of avifauna, of which 6 are migratory and 51 resident species.[2] It is also reported that about 40 species of wetland-dependent birds are recorded in the lake, out of which 45% are long-distance migrants. Terns, plovers, cormorants, and herons are most abundant birds in the lake.[3] A study report has identified 45 insect species, including 26 species of butterfly, 5 odonates, 9 hymenopteras, and 2 orthopterans, 1 hemipteran and 2 coleopterans. About 29 zooplankton species have also been identified.[3] The water body is found to have 9 phytoplanktons such as Amphora, Borosigma, Cyclotella, Cymbella, Gyrozigma, Meloziva, Navicula and Nitzschi.[3]

World Wildlife Fund (WWF) reports

97 species of fish (42 are typically marine, 3 estuarine, 9 estuarine-riverine, 15 marine-estuarine) and unique copepod species. It is also a congenial habitat for all species of penaeid and palaemonid Prawns, edible crabs, paphia malabarica (short neck Clams) and a variety of fish. A comparative shell morphology study of short-neck clam Paphia malabarica, the main clam fishery resources in the Ashtamudi Lake re-assigned to the genus Marcia recens (Venus Clams) and this study found it was wrongly identified as short-neck clam in previous studies.[12] Clams found in the estuary are exported.[2] The estuary is the source of livelihood for thousands of fishermen and is stated to be the second biggest fish-landing centre after the Vembanad estuary.[10]

An uninhabited island in Munroe Island cluster, situated at Lake Ashtamudi

Munroe Island (Munroethuruth) is a cluster of eight tiny islands in Ashtamudi Lake.

Chavara South, a small village, an island within the Ashtamudi Lake, located 14 km (8.7 mi) away from Quilon on the National Highway NH 47, is reported to be mineral rich with number of factories for extraction and export of titanium and other minerals. Effluent from the factories is reported to be causing pollution of the lake waters.[13]

Thekkumbhagom island, situated on the bank of the Ashtamudi Lake, provides the feel of rustic life of a village. The significance of this village is because the first epic poetry in the Malayalam language, Ramachandravilasam, was composed by the poet Azhakath Padmanabha Kurup in this village. An ancient 1000-year-old temple and a 200-year-old church are located here.[1]

An evaluation of the marketed use benefits of Ashtamudi estuary (valued using market valuation approach) has assessed the total direct use value at Rs.66.8 million per annum; coconut husk retting accounts for Rs.5.1 million, Inland navigation service accounts for Rs.3.7 million and the recreation benefit is assessed at Rs.1.5 million (using the standard travel cost method). But this is reported to be showing a downward trend, particularly in fish resources in the estuary. This evaluation provides an insight into the economic importance of conserving Ashtamudi estuary.[14]

A moving ferry on Lake Ashtamudi at Kollam city

The following are reported to be the reasons for deterioration of the lake environment:[2][10]

1. Intense anthropogenic pressure.
2. Oil spills from thousands of fishing boats and from industries in the surrounding area.
3. Dwindling of the fragile lake zone due to conversion/destruction of natural habitats for development purposes (reported that the lake which had an area of 54 km² [21 mi²] according to old survey reports has shrunk to 34 km² [13 mi²] due to encroachments)
4. Large quantities of untreated sewage, disposal of human excreta, and the pollution from paper mills, industries (aluminum, ceramics, seafood), as well as from coconut husk retting.
5. Many fish species may have become extinct due to lack of spawning facilities on the banks of the lake due to canalization of the lake's banks by walls built of laterite and granite stones (these walls reportedly cover 80 per cent of the lake's banks)

A house boat seen in Ashtamudi lake with Chinese nets in the background

The Asia Development Assistance Facility of the New Zealand Government has carried out a study with the objective of evolving a management plan for sustainable management of the estuary for ecosystem development. The shores of the lake are home to important species of rare birds and animals. Any decisions made concerning the Ashtamudi Estuary's resources and its sustainable management significance is dictated by about a million people who live on its shores and the large species of rare birds and animals which provide the equally important biodiversity to the lake's environs.[10] The Plan envisages:[15]

• Identify and phase out of the pollution sources
• Better sanitation, reduction of industrial growth and reduction of urban waste to ensure the maintainable water quality of the estuary.
• Address the declining fish stock production through concerted efforts to conserve the fish stock of the estuary in a sustainable manner and with community participation
• Product diversification of coir to ensure better economic returns to people with the coordination of self-help groups
• Improved shore protection through mangrove afforestation for ecosystem development on the banks of the estuary
• Mining to be allowed selectively at village level, away from the banks of the lake
• Discontinue estuary reclamation
• Set defined navigation routes undisturbed by fishing nets
• Neendakara port to be provided with improved sanitation facilities, enhanced boat-fuelling terminals and drainage terminals.
• Promote ecotourism with better facilities of inland navigation and services in the form of:
  • developing of marine bio-reserve, nature island and mangrove conservation area
  • visits to temples nearby and other places of cultural and archeological importance
  • visits to coir-producing villages, rubber-producing villages, rice fields, fish hatcheries and other biodiversity hot spots

The above activities have been suggested for implementation in the Vellimon Kayal, a relatively unspoiled part of the estuary.

With funds provided by the Union Ministry of Environment and Forests, revival of mangrove forests was done which is reported to be partially successful (out of 2,40,000 mangrove saplings planted over a period of two years 30,000 are reported to be surviving).[10]

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  Backwaters at sunset
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  Lake near Kollam KSRTC Depot
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  Ashtamudi Lake with Quilon on its banks
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  Mechanised boats plying in the backwater
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  As the lake joins the sea
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  Ducks in the lake
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  Houseboat in the midst of weeds in the backwaters
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  Traditional Chinese fishing net in Ashtamudi Lake
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  Traditional merchant boat on the backwaters (Kerala)
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  Ashtamudi Lake
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  Ashtamudi Lake 2

Wikimedia Commons has media related to Ashtamudi Lake.

• Ashtamudi Lake on World Wildlife Fund-India website