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Menon and George - UEI Day 2 - Kochi Jan18


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Menon and George - UEI Day 2 - Kochi Jan18

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Menon and George - UEI Day 2 - Kochi Jan18

  1. 1. NANDINI MENON1 AND GRINSON GEORGE2 1Nansen Environmental Research Centre India 2 ICAR-Central Marine Fisheries Research Institute
  2. 2. Introduction  State of Kerala is a strip of land with a coastline 590 km long and width varying from 11 to 124 km.  Based on the geometry, geologic and geomorphic setting, the Vembanad kayal is characterised by its long axes running parallel to the coast (coastal plain formation of quaternary period) and is separated from the sea by barrier spits interrupted by tidal passes (Soman, 1997).  The large backwater extends from Munambam at north to Alappuzha at south for a distance of 100 km on the south- west coast of India (090 00’ – 100 40’ N Latitude and 760 00’ - 770 30’ E Longitude).
  3. 3.  The width varies from a few hundred meters to 14 km.  Two rivers, Periyar and Muvattupuzha discharge into the backwaters, whereas Thannirmukkom bund regulates the flow from four rivers namely Meenachil, Manimala, Achankovil and Pamba.  The bathymetry of the waterbody indicates that depth variation occur between 1.5 m and 6.0 m in most parts except the dredged channels, which are 13-15 m deep.  The sediments are a mixture of clay and silt (70–85%) and sand.  Ramsar site
  4. 4.  The climate is typical of tropical features with monsoon (June– September) yielding 60–65% of the total rainfall (approx. 300 cm).  The backwaters, a typical positive estuary houses the second largest port along the west coast of India.  During monsoon season, heavy rainfall results in high river discharge which results in less dense river water at surface and high dense seawater at the bottom layers (salt-wedge).  In post monsoon, river discharge gradually diminishes and tidal influence gains momentum and stratification weakens.  In pre-monsoon, river discharge is minimum and seawater influence is maximum, the estuary is in a well mixed condition.  Development of turbidity maxima during high tide within the estuary is very noticeable.
  5. 5.  Northern parts of the estuary are subjected to higher salinity wedging and oscillatory movement with vertical temperature exchange than the southern parts.  With the installation of Thanneermukkom bund, stratification is pronounced in the lower reaches of Periyar river (northern parts of the estuary), while the southern parts appear to be well mixed.  Thottappally spillway, 20 km south of Alappuzha on NH-47, was commissioned in 1955 to enable easier outflow of the combined flood discharge from Pamba, Achencoil and Manimala rivers to the sea. But it failed to bring in the desired results
  6. 6. Thanneermukkom bund •1.441 km long bund constructed in 1976 to prevent salt intrusion into the low lying paddy fields of Kuttanad region. •The bund is the southern boundary of Kochi backwaters. •Construction of Thaneermukkom Bund disrupted water exchange transforming the southern part into more or less a stagnant fresh water pool. •The hydraulic barrier across the estuary has been successful in preventing salt water intrusion and increased sedimentation in the estuary. •The progressive ecological degradation inflicted on the entire estuary is severe The tidal flux between riverine and estuarine regions was affected by periodic opening and closure of the Bund.
  7. 7. Reclamation •The backwaters face serious environmental threats by land reclamation, expansion for harbour development, dredging activities, construction of dams and urbanisation. •Major changes began with the construction of Cochin Port (1930- 1940) and reclamation of Willingdon island. •Reclamation has reduced carrying capacity of Lake from 2.4 km3 to 0.6 km3 •The Kochi backwaters has suffered natural and man-made shrinkages over the years, and its mean depth has reduced to ~66% during the past fifty years.
  8. 8. Biodiversity  Vembanad lake supports as much biological productivity and diversity as tropical rain forests.  Salinity controls the species composition and succession of flora and fauna.  Phytoplankton ranges from typical marine form Coscinodiscus sp. to fresh water form Cyclotella sp.  Nanoplankton is an important component in the primary producers.  14 genera of freshwater phytoplankton were identified during monsoon from the area.
  9. 9.  Among zooplankton, the dominant forms are copepods (55- 85%).  The hydromedusa Eutima commensalis and the sergestid shrimp Acetes cochinensis are endemic to Cochin backwaters.  Pre-monsoon brings in typical saline forms like chaetognaths and ctenophores  Low lying swamps and tidal creeks, dominated by sparse patches of mangroves with their nutrient rich physical environment, support larvae and juveniles of many economically important species.  Larvae and juveniles of commercially important prawns like F. indicus, M. monoceros, M. dobsoni, M. affinis, Macrobrachium rosenbergii are all found in the estuary.  Benthos represented by wood borers, biofoulers, bivalves, meio and macro fauna, other crustaceans including prawns (Menon et al., 2000)  Black clam Villorita cyprinoidess
  10. 10. Effect of water quality degradation on fish diversity of VKW  Many of the wild species of fishes which were previously available in plenty is now extinct or rarely spotted and a few others are on the verge of extinction(Vembanad fish count, ATREE, 2008-2011)  Vembanad Fish Count (VFC) conducted in May 2013 found that the number of fish species decreased from 62 in previous year’s fish count to 58 species in 2013.  A steady decrease in number of Puntius was reported  Increased number of Tilapia has led to decrease in indigenous species  Fishing gears and traditional fishing operations are adversely affected by the solid wastes and weeds in Vembanad lake.  Clogging of nets by masses of macroalgae and other plastic debris is common. Most of the catches are discarded due to tainting and most fishes smell and tastes kerosene.
  11. 11. Mud banks (CHAKARA)  Activity of longshore currents bringing in sediments into the channels lead to the formation of mud banks.  Mud banks are regions of calm and highly turbid waters that occur along certain parts of the Kerala coast during summer monsoon season when the coastal region experiences high wave activity.  The area offers fishing opportunity for fishermen during the monsoon season when normal fishing activities become difficult in rough weather.  The occurrence of mudbanks have come down drastically over the years.  Even after several studies, the generation, sustenance, dissipation and localisation of mud bank are yet to be explained satisfactorily
  12. 12. Pollution • Industrial area of Eloor with over 247 chemical industries such as petrochemical, pesticide, rare earth elements, fertilizer, zinc and heavy metal products is characterised as the ‘Pesticide loading site’. • Agricultural run-off result in high pesticide values (1.4 – 13.01 µg/l of Malathion) in Kuttanad region. • Faecal coliform and biochemical oxygen demand of lake very high. • Microplastics • Excess feed and fish waste discharged from the aquaculture farms. • Invasive and nuisance species of water plants. Pathogenic bacteria and viral pollution (bacteria are antibiotic resistant).
  13. 13. • Radionuclides like Ra-228 and Ra-226 found in high concentrations in the industrial zone. Source – fertilizer industry. • Decreasing fish yield. Fin fish diversity reduced from 50 species in 2008 (ATREE, 2008) to 42 in 2014. • Based on the presence of indicator algal genera, Palmer pollution index value was calculated. Palmer Index – 20 - indicates organic pollution of the lake. • Rapid industrialization and urbanization in the last few decades resulted in discharge of about 1.04 x 105 m3 d-1 of effluents and 260 m3 d-1 of sewage into the CE (Qasim 2003; Balachandran et al. 2005) • The level of coliforms in most of the stations of the study region were above 1100/ 100ml.
  14. 14. Kuttanad •Kuttanad is a fragile wetland eco-system; a delta covering approximately an area of 1,100 km2. •Area well known for its vast paddy fields and geographical peculiarities popularly known as ‘Rice Bowl of Kerala’. •Area of reclaimed land, separated by dykes from water which is higher than it appears. •The only place in the world where farming is done up to 2 meters below sea level •Rice cultivation has been the primary livelihood. •Kuttanad Package: Central Government scheme where funds are transferred based on ‘project proposals’- oriented to ‘water resources development’ .
  15. 15. Agriculture  The traditional agriculture known as pokkali cropping system.  It is a rice- shrimp rotational cropping system. These pokkali fields are highly productive coastal wetland ecosystem which produces enormous quantity of special variety of paddy and palatable shrimp and fish depending on season.  Adjoining the 590 km long coast line there are 26000 ha saline paddy (pokkali) fields.
  16. 16. Paddy-cum fish/ prawn culture  Rice farms 1‐2 metres below sea level  A major problem for second crop is flooding of fields due to breaches in the temporary bunds.  Salt tolerant strain of paddy cultivated in coastal areas for six months from May to October.  Filtered shrimp or Prawn or fishes culture during November to April under traditional farming system of about 12,986.6 ha in Kerala.  The major shrimp varieties are filtered during the entry process by sluice gates and filtering net curtails the entry of unwanted species into the culture system and also prevents the escape of cultured species out of the system.  Rice cultivation alone not profitable under the organic farming, but the overall Pokkali farming system is made highly profitable by including prawn cultivation in the succeeding season
  17. 17.  Pokkali rice farming is fastly approaching towards extinction stage because of shortage of farm hands for harvesting, increased weed problems, shift to monoculture of prawn farming, and conversion of fields for purposes such as roads, residential activities etc.  Recommended a Pokkali rejuvenation Mission to save the unique cultivation of paddy in saline waterlogged lands in Ernakulam, Alappuzha, and Thrissur Districts from extinction in the year 2012.
  18. 18. Pollution and Decline of prawn fishery  Macrobrachium rosenbergii population in the estuary is dwindling.  Thanneermukkom bund which prevents the migration of the juveniles into the brackish region of the estuary is the major causative factor.  Along with it, the habitat destruction and pollution are causative factors.  Fishery of Etroplus, the state fish of Kerala, has progressed in the years, even after commissioning of Thanneermukkom bund.
  19. 19. Tourism • Internationally well known tourist destination. • God’s own country” one of the most important tourist destinations in India. • National Geographic Traveller: selected Kerala as one of the “50 must see destinations in the world”. • Some ~2000 houseboats operate in the area to serve the tourists. • There are a number of tourist resorts nestling on its banks. Vembanad bird sanctuary is located at Kumarakom and Pathiramanal, where a large number of tourists congregate during October-March every year – it being the peak season.
  20. 20. Contribution of houseboats in degrading the water quality of the ecosystem  In case of Vembanad lake 80% of debris comes from land and rest 20% comes from tourism related activities.  Solid waste, trash and other plastic wastes are discarded into the lake from houseboats which are seen floating on water.  Majority of the houseboats release their sewage waste directly into the water when they reach areas of fairly good water circulation like Thottapally.  Chronic discharge of solid wastes and sewage is seen also in parking areas like Kavanttinkara, Cheepunkal, Punnamada contributing to the high bacterial load.  The cumulative effect of many boats discharging sewage proves to be more harmful in this case.  Pathogenic contaminants such as Streptococci, faecal coliforms and other bacteria cause infectious hepatitis, dysentery, diahorrea, skin diseases and in extreme cases cholera and typhoid.
  21. 21. The minimum average area of each houseboat engine of 100 hp is estimated as 50 acres per boat (Rajan et al., 2011) The usable lake area under the study is (based on GIS mapping) Carrying Capacity = 501/180 = 2.78 Percentage at peak use = 501/180 *100 = 278% = 90.31 = 180 boats  Only 180 houseboats are allowed to operate in the lake at a time  Estimated no: of houseboats at peak time = 501 (Port Trust data, 2012) Recreational boat carrying capacity of the lake has exceeded the limits and this exponential growth must be arrested or controlled to prevent further destruction of lake caused by house boat operations. Optimal boating density= Usable lake area/ optimum boating density
  22. 22.  Houseboats and resorts are one of the major factors contributing to the degradation of Vembanad lake.  Low dissolved oxygen, high pH, high level of nutrients indicates the high organic pollution in the lake  Plankton and fish diversity of the region has reduced considerably together with the emergence of highly pollution resistant species.  Oil pollution is more alarming in areas of high houseboat activities. High organic carbon in sediments renders the persistence of harmful PHCs in the lake which are highly toxic to flora and fauna of the lake.  Carrying capacity of the lake has exceeded the limits and hence stringent measures have to be adopted to regulate the houseboat activities in the lake.  Houseboat operations have adversely affected the socio-economic life of the local people  Ecosystem Health Index assessment reveals that the lake is under high organic pollution.
  23. 23. Dependence of community to Vembanad lake  Fishing, duck-rearing, clam collection, toddy tapping, canoe-making, water transporting, coir weaving too have been the notable traditional sources of livelihood.
  24. 24. Coastal Vulnerability CA  The coastal land up to 500 m from the High Tide Line (HTL) and a stage of 100 m along banks of creeks, estuaries, backwater and rivers subject to tidal fluctuations, is called the Coastal Regulation Zone(CRZ).  CRZ-1, CRZ 2, CRZ 3, CRZ 4.  Kerala is the only state for which violation mapping was carried out throughout the coasts. Though Kerala has a well-prepared CZM Plan, the State’s interest is to relax the notification so as to accommodate the ‘development’ in the state.
  25. 25. Dependency Index Governance Index Resource Use Index Resource Use Perception Index Conservation Perception Index Management Perception Index Demarcation of Resoure Areas Collection of Census Data CVCA Decision Framework Willingness to Participate Index Community Participation Index Integrated Social & Natural Capital Index
  26. 26. Ability to GovernLow Low High Hig h Direct Dependence Demarcation of Resource Areas Collection of HH / Census Data CVCA Decision Framework Communi ty Managed Areas - CVCAs Intervent ion Capacity Building HIGH Dependence; LOW Governance Ability HIGH Dependence; HIGH Governance Ability LOW Dependence; LOW Governance Ability LOW Dependence; HIGH Governance Ability Interventi on Skill / Business Models CRZ I / ESA State Managed The Decision Matrix… An Illustration
  27. 27. Business history  Coconut – husk – coir retting
  28. 28.  The first coir factory was established in the ancient port town of Alappuzha in the year 1859.  Household units are engaged in fibre extraction and spinning of coir yarn throughout the coir producing regions.  The industry employs about 7 lakhs of coir workers and majority of them are from rural areas belonging to economically weaker sections of the Society.  Women constitute 80% of the work force in the industry.  Coir retting and dyeing industry has led to serious pollution problems.  High values of hydrogen sulphide, ammonia, BOD associated with anoxic conditions and low community diversity of plankton, benthic fauna, fish, shell fish, wood boring and fouling organisms were the outstanding feature of the retting zones.
  29. 29. Thakazhi
  30. 30. Banana cultivation and water quality  Banana cultivation-another major income.  Being a long duration crop, the total water-per year requirements are high, varying between 1 200 mm in the humid tropics to 2 200 in the dry tropics.  In the banana industry, water management practices have significantly reduced its water footprint, defined as the measure of the consumption and contamination of freshwater resources for the production of a good or service.
  31. 31. Alien species  Unregulated introduction and illegal farming of several new exotic species has been documented in the recent past. Several of these species are listed as potential pests, capable of negatively impacting the native aquatic biodiversity.  Clarias gariepinus  Salvinia molesta  Limnocharis flava  Achatina fulica  Eichhornia crassipes
  32. 32. Vectors, diseases • Vembanad Lake has been characterised as one of the most polluted water bodies in all India. • In a list compiled by DST under its War for Water Mission, Ernakulam and Alappuzha (the two main administrative districts on the lake) have been identified as key sites for study of the effect of biological contamination on water quality in India. • Coliform bacteria represent a major problem: the lake serves as an aquatic reservoir for various water-borne infectious diseases, including cholera and dengue.
  33. 33. Conclusions  Unscientific developmental activities have led to the deterioration of water quality of Vembanad lake.  Interests of all sectors – agriculture, fishery, industry, urban population – to be taken into consideration when any reform is introduced or undone.  Unbridled tourism has to be curtailed.  Water stagnation in the lake to be resolved.