Sasthamkotta Lake and its struggle for existence

Around 29 kms away from the city of Quilon/Kollam is Sasthamkotta Lake- the largest freshwater lake in Kerala which is, since November 2002, one among 25 sites in India designated as a wetland of international importance under the Ramsar Convention. The lake has a surface area of 373 ha and an average depth of 6.53 m (the maximum depth being 15.2 m). Since no tributaries feed the lake, it is believed that its existence is owed to rainfall as well as the springs at the bottom of the lake which supposedly stem from the nearby Kallada river.

The lake, with its pH of 7.25, serves as a major drinking water source for the inhabitants of the Kollam district. And the large population of chaoborus larvae (glassworm)* is believed to consume bacteria in the lake, thus maintaining the water’s purity. The aquatic fauna includes Etroplus suratensis (Pearl Spot or ‘karimeen’) and catfish. It is also a favourite habitat of the Common Teal (Anas crecca). Of special importance are Puntius ticto punctatus (the critically endangered Ticto barb), Horabagrus brachysoma (the endangered sun catfish), and Parambassis thomassi (vulnerable), as reported by WWF. WWF’s report also states that lake lacks aquatic flora and has scarce phytoplanktons**- claims which cannot be generalised for botanists have collected flora such as Nymphea, Limnanthemum, Lemna, Elodea, and Hydrilla from the lake.

The lake has been in the limelight recently- its environmental quality has been deteriorating, and both its surface area and the water level has been decreasing (in May 2010, 24 hectares of the lake was parched). The reasons are:
- Encroachment/reclamation for agriculture (mainly paddy, plantain, and tapioca)
- Unauthorised sand mining, including clay and sand mining in the surrounding hillocks which serves as catchments
- Soil erosion on the banks (the acacia trees which were planted with the purpose of stopping erosion have also stayed true to their reputation as water depleters).
-Dumping of agricultural and domestic wastes
- Dumping of wastes by restaurants and butchers
- Dumping of domestic/municipality sewage via gutters
- Soaking of dry coconut palm fronds before weaving
- The usual norm of local residents bathing and washing clothes (also cattle) in the lake.
- Accumulated eroded material at the bottom of the lake.

There may be some solution after all. The local government drew up a master plan for protecting the lake, and July 2010 saw those who lived around the lake being given a notice banning them from taking baths, washing clothes, or dumping waste into the lake. The notice also forbids mining in the catchments. In September, Sasthamcotta Lake and its surrounding catchments areas were declared as protected. Quarrying, sand-mining, and other activities which pollute the lake have been banned for two months. A longer term ban would have been more appropriate- a two month ban cannot achieve anything substantial, if any.

Postscript:
Whilst researching this topic, it was evident that the primary source used by most reports/articles was the Information Sheet on Ramsar Wetlands filed in by WWF, which may have a degree of inaccuracy.

* The WWF report’s ‘cavaborus larvae’ is probably a typo (or an ignorant error). Nonetheless, there are now 122 google results for the same term associated with the lake.

** A lake with no plants, minimal phytoplankton, and many fish species? Shurely shome mishtake?

References:
Information Sheet on Ramsar Wetlands(RIS)
The Annotated Ramsar List: India
WWF on Sasthamkotta Lake

http://www.hindu.com/2010/09/11/stories/2010091153010500.htm
http://beta.thehindu.com/news/states/kerala/article429986.ece
http://timesofindia.indiatimes.com/india/11-more-wetlands-in-Ramsar-list/articleshow/32390259.cms