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Understanding the ecosystem services of Vembanad Lake

Vembanad lake system is the largest wetland system in India comprising of 2033 area approximately falling into roughly three districts of Kerala with ten rivers draining into it to eventually join the sea. It is the largest brackish water wetland area in the South western coast of India and is a designated Ramsar site that supports a wide variety of avian fauna, aquatic species and wetland adapted fauna.

Given the extremely sensitive eco-zone the area is, there are considerable changes that have negatively impacted the region. In order to understand these changes as well as to assess its susceptibility to future changes it is necessary to undertake an ecosystem services based analysis to chart out the vulnerability of the region.

Ecosystem services mapping is to try to list out the subset of the interactions between ecosystem structure and processes that underpin the capacity of an ecosystem to provide goods and services. In order to do so we need to identify the various ecosystem service providers (ESPs) and then see how these ESPs function in their natural landscape with the various community structure aspects, understand the various environmental factors that interact with ESPs and influence their functions and then measure the scale and temporal dimensions in which they operate.

Any wetland system is an important meeting point of numerous ecosystem services in their regions upon which directly or indirectly the people in the region depend upon for their livelihoods and everyday life activities. Ecosystem services can be classified on the basis of the nature of services provided. According to the Millennium Ecosystem Assessment, these services include provisioning, regulating, supporting and cultural. In economic terms the services can be classified in somewhat overlapping understanding of Use value and Non-use value. While provisioning services include the direct products we derive from wetlands such as food resources, raw materials etc.; the regulating services would include the indirect services such as purification of water, groundwater aquifer recharging etc., Supporting services would include nutrient cycling, habitat provision etc. Cultural services are a bit tricky and vague but include the value derived from the system due to cultural association with the wetland or more recognisably existence value of the system in terms of economic valuation.

Vembanad ecosystem is no different from this but provides some unique and crucial services that vary from other wetland systems due to its geography and composition.

The main ecosystem services provided by Vembanad Lake include floodwater regulation; livelihoods provisions; drinking water; eco-tourism; religious solace etc. These broad stroke of services include numerous subsets that cater to the overall integration of the lake with local life.

The primary function provided by the system includes Flood regulation in the region which includes three populated districts in Kerala. These areas that are at below sea level, partially submerged throughout the year do not experience high levels of flooding caused by the south-west monsoons due to storm gate channels provided by the lake and its estuaries. If this service were to be compromised, the State would have to compensate in terms of displacement of millions of people in these districts, loss of their livelihoods (temporarily or permanently), infrastructure loss caused by the flooding as was experienced in the Kerala floods of 2018 but to a greater extent given the probable rise in frequency and intensity of extreme events due to anthropogenic climate change. Reclamation of these wetland lands due to developmental pressures of agriculture, urbanising etc. would block the storage functions that the estuaries provide for excess water draining into the lake during monsoons and the subsequent recharge of groundwater levels for the provision of drinking water to the locals in the region.

Livelihoods in the region are predominantly dependant on the lake ecosystem and its stable functioning. These would include fisheries (inclusive of freshwater fishes and clams), agriculture, coir manufacturing, paper industries and lime production industries in the lake region. In the region where fisheries and agriculture successfully functioned co-dependently in the earlier eras, anthropogenic interventions in the lake such as that of the Thanneermukkom salt water barrage has created obstructions in this smooth balance upsetting both the industries. Due to the low intrusion of saline water into the lake during the dry season as it occurred earlier, freshwater fishes and clams have dropped drastically due to the lack of appropriate breeding conditions created naturally in the system prior to the intervention.

The lowering of clam population specifically has had an adverse impact on the livelihoods of clam collectors in the region. This has also led to drop in species diversity in the region with respect to fishes available in the lake. Species diversity and individual species strength in numbers ensure future propagation in the lake and maintaining the biodiversity in the system which also happens to be a recognised Ramsar site. Clam collectors earlier engaged with the collection of white clams (sub-fossils) due to the calcium carbonate rich clam shells in the lake that were in much demand and fetched higher prices due to its use in carbide factories, later had to shift to the specific variety of black clams available in the lake due to the excess harvesting of white clams and lower availability thereafter. The freshwater black clams are harvested and processed both for their meat and extraction of lime from the shells. The barrage has hit the live black clam shell collectors to a great extent due to the dearth of saline water that is required for breeding leading to drop in numbers. Excessive harvesting of live clams even the tinier ones due to demand, without giving them an opportunity to propagate their numbers in the different regions of the lake have further lessened their population. The drop in clam numbers also adversely affects water quality in the lake region due to the water purification characteristic of clams. Clams purify up to 17 litres of water every day.

Considering the extent of pollution in the lake given the rates of urbanisation, development and tourism it is an important regulating service provided by the ecosystem that is not even taken into consideration while valuating the loss occurred by the reduction in clam numbers. These freshwater species easily available in the region serve as a cheap protein source to people living in the vicinity who are rendered vulnerable given the unstable conditions of agriculture in the region which is prone to harvest losses due to unpredictable rains and flooding. The unscientific operation of the barrage that was initially brought forth to encourage a second crop of paddy has led to a clash between two important economic stakeholder associations which are that of the fishermen associations including the black clam traders association and that of the paddy cultivators.

The State is now torn between weighing the demands of both the stakeholders and making decisions on an economic basis that is beneficial to the entire state and more often than not agriculture gains the upper hand because of concerns relating to food security. But in any scenario the demands of one stakeholder shouldn’t be pitted against the other but both the parties should be given equal consideration which hasn’t been the case in this situation for the past many years. The so called scientific intervention undertaken was to encourage paddy cultivation not taking into consideration the numerous ecosystem services provided by the lake naturally free of cost that would be disrupted due to the barrage and even other interventions such as that of the Thottapally spillway that was supposed to redirect flood waters but wasn’t effective to the capacity envisioned and now is just an obstruction that further disrupts the natural drainage processes of the lake ecosystem.

Agriculture in the region that has integrated itself into the lake ecosystem from 18th century onwards using particular techniques of lake-bed, below sea-level paddy cultivation has come to incorporate unsustainable and toxic methods by the use of excess amount of pesticides and fertilisers to increase productivity in the region. Due to the specific conditions in this type of agriculture, the effects of toxicity is visible in a short time span in the lake water. The lake water that was considered the primary source of drinking water in the region now isn’t fit for human consumption. The excess nutrient content in the lake has led to the extensive growth of aquatic plants in the lake which when buried and decomposed by bacterial reduction lead to shallowing of lake by silt depositing. This has an adverse impact on the life of aquatic organisms that now have reduced dissolved oxygen content in the lake. While a particular section of the society benefits from agricultural production in the region and even the regular flooding due to silt deposit that makes the lake bed fertile for paddy cultivation this has had an overall negative effect on the lake ecosystem.

Tourism in the region is an important component of economy of the State. Alappuzha region of Vembanad houses around 1000 houseboats throughout the year. These houseboats entertain tourists and promote an idea of eco-tourism to Kerala, God’s Own Country. These houseboats bear the ire of both agriculturists and fisher folk in the region due to the largescale pollution of lake water and the surrounding environment due to the wastes generated by tourist boats. While interventions in this regard have ensured that organic human wastes are collected at demarcated locations in periodic intervals, tourists also manage to dispose plastic wastes directly into the water despite knowing better. Organic kitchen wastes from these boats are also deposited into the lake which again lead to conditions of oxygen content dip in the lake that is harmful for aquatic life. Quality of lake water is also diminished due to the flow of fuel contents from the boats (both from tourist as well as fisher boats) into the lakes.

Cultural services provided by the lake are also crucial to the communities residing in the region. The lake being the lifeline of communities residing in this region of the state it is but an organic extrapolation of their spiritual manifestations also. Many communities in the region worship the lake as the source of their livelihoods and they associate the degradation of the lake with a spiritual apathy in the current era that gives precedence to greed over the source of that livelihood. For regions farther away the rivers draining into the lake are connected to important pilgrimage sites. Cultural services would also include the imagery of the region which the local community as well as the diaspora associate with strongly such as that of the paddy fields of Kuttanad and the scenic beauty of the serene Vembanad Lake. It is also the association of the lake with important cultural event such as that of the Nehru boat race conducted every year which people strongly emote with. These are the same images that are portrayed to increase tourism revenues to the State as well.

The effects of pollution economically takes into consideration both the loss of ecosystem services as well as the cost of mitigation efforts. Presently the Kochi Water Metro Rail Ltd. (KMRL) in collaboration with a German company are undertaking a project to clean Vembanad lake region to clear the area for a water metro project currently estimated at a cost of 740 crores. This giant chunk of the project budget just to restore the lake to its less polluted state if not original, processes which happened naturally earlier and also provided a trade and transport lifeline to the people in the region way before foreign companies and metro projects were envisioned. Other than pollution and other anthropogenic contributors to the deterioration of the lake, one of the major problems that will be encountered in the future will be climate change induced effects. While the exact effects cannot be anticipated we can expect a probable rise in the frequency and intensity of extreme events in many regions of the world. These events will have an amplified effect in already vulnerable regions such as the Vembanad lake area due to the specific socio-economic conditions of a developing nation as well as the topographical location of the state of Kerala. While floods might not be a new aspect for the people in this region of the country, the 2018 floods demonstrated the widespread destruction of property and lives due to unprecedented and unanticipated extent of the floods. The economic losses incurred due to the floods have been pegged at approximately 3000 crores in the state. These losses still do not take into account completely the loss of various ecosystem services in the region due to the floods and also because of activities undertaken way before the floods. Such a situation arises out of ignorance of the State and the stakeholders in the possible effects of their actions or its lack thereof or as happened in the case of Thanneermukkom barrage we simply lack the means to know beforehand the nature and extent of potential damages.

Therefore in understanding vulnerability specifically of sensitive eco-zones such as the Vembanad system, it is necessary that we account for as many ecosystem services as possible and chart out their inter-linkages. While there are numerous other services that haven’t been charted out in this report, it is but an attempt to connect the various aspects of the physical, biological and civilizational dimensions that comprise the Vembanad Lake system.

The author, Mishel Mohan worked as an intern with ATREE CERC. Currently she is working with Sphere India as Disaster Governance and Risk Reduction Fellow


  1. Woodward, T. Richard. 2001. The economic value of wetland services: a meta-analysis.

  2. Maltby, Edward (ed.). 2009. Functional assessment of wetlands: Towards evaluation of ecosystem services.

  3. Committee on Assessing and Valuing the Services of Aquatic and Related Terrestrial Ecosystems. 2005. Valuing ecosystem services: Toward better environmental decision-making.


  5. K. N. Remani, P. Jayakumar, T. K. Jalaja. 2010. Nature Environment and Pollution Technology Vol. 9 No. 2 pp. 247-254: Environmental Problems and Management Aspects of Vembanad Kol Wetlands in South West Coast of India.


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