muturajawela wetland (sri lanka)
TRANSCRIPT
Muturajawela Wetland
Kamal Prasad De Zoysa Siriwardena
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Index
1 Introduction .................................................................................................................. 2
2 Study method ............................................................................................................... 3
3 Investigations ............................................................................................................... 3
3.1. Overview of the Muthurajawela ........................................................................... 3
3.2. Social and cultural values ..................................................................................... 4
3.3. Direct economic uses of wetland resources ......................................................... 5
3.4. Indirect economic benefits of wetland ecosystem services ................................. 6
3.5. Flora & Fauna of Muturajawela ............................................................................ 7
3.6. Conservation measures ........................................................................................ 9
4 Finding .......................................................................................................................... 9
5 Recommendations ...................................................................................................... 11
6 References .................................................................................................................. 14
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1 Introduction
In the past, wetlands were considered as wastelands that could be reclaimed or changed for
use by mankind. Development initiatives have regarded these areas suited only for such
purposes, and as a consequence, many wetlands have been drained or used as dump sites for
refuse and urban waste. With increasing knowledge however, we have come to understand that
wetlands are amongst the world’s most valuable and vulnerable environments on which a
variety of plants, animals and human communities depend (IUCN Sri Lanka, CEA, 2006).
Sri Lanka has a wide array of inland and coastal wetland ecosystems that harbor a rich
biological diversity. One such urban wetland in Sri Lanka is Muthurajawela, the largest coastal
peat bog of the island located on the West coast. Muthurajawela Marsh covers an area of 3,068
ha. It is located between 10-‐30 km north of Colombo, in Gampaha District. Together with
Negombo Lagoon (3,164 ha), Muthurajawela forms an integrated coastal wetland system of high
biodiversity and ecological significance. Due to its importance certain parts of this wetland has
been declared as wildlife sanctuary during 1992.
However, despite its protected status, Muthurajawela is subject to intense and growing
pressures. Areas within and surrounding the wetland have since 1991 been zoned for urban,
residential, recreational and industrial development. Wetland species are harvested at high and
often unsustainable levels, land is being rapidly reclaimed and modified for agricultural,
commercial and residential purposes, and heavy loads of industrial and domestic wastes are
discharged untreated into the marsh. The wetland area has been seriously degraded over time,
and these threats continue to intensify (Lucy, Kekulandala, 2003).
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2 Study method
To conduct this study about Muturajawela I have visited this site and data and information’s
were collected through direct observations, face-‐to-‐face interviews and literatures such as
research papers etc.
3 Investigations
3.1 Overview of the Muthurajawela
Muthurajawela is the largest saline coastal peat bog in Sri Lanka, located on the west coast
(7003’N,79055’E) between the Negombo lagoon and Kelani river and spreading inland upto
Ragama and Peliyagoda in the Gampaha District (Figure 1). The marsh, together with the
Negombo lagoon forms an integrated coastal wetland ecosystem (6,232 ha in total extent). The
marsh-‐lagoon complex is estimated to have originated about 5000 years BC (CEA/ Euroconsult,
1994). The main water source to the marsh is Dandugan Oya which drains a catchment of 727
km2 and discharges at the interface of the lagoon and the marsh, while the marsh is traversed by
a navigational canal constructed during the Dutch colonial period. The area receives an annual
average rainfall of 2000-‐2500mm, while the average annual temperature is 27oC (Samarakoon
and Renken, 1999). According to historical evidence, Muthurajawela was subjected to extensive
cultivation of paddy, more than 500 years ago (GCEC/Euroconsult, 1991).
The Muturajawela marsh is located within the low country wet zone and is influenced by the
southwest monsoon. The highest rainfall is received during the inter-‐monsoon periods in April
and May, and in October and November, with an annual rainfall between 2,000 – 2,500 mm. The
soil is a uniform, potentially acidic sulphate, and the land is poorly drained with a peaty
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substrate which is saturated for almost the whole year (IUCN,2006).
3.2 Social and cultural values Around 5,000 people live in or directly adjacent to Muthurajawela marsh, although the
majority engaged in low-‐paying manual labour activities. A few traditional fishing families are
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Figure 1.Location of Muthurajawela wetland sanctuary
SRI LANKA
MUTHURAJAWELACOLOMBO
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involved in small-‐scale commercial and subsistence fisheries in the canals, the Dandugam Oya
and marsh lagoon transition zone. The canals running through the wetland were developed and
used for transportation of goods during the Dutch period (Lucy, Kekulandala, 2003).
3.3 Direct economic uses of wetland resources
Fishing: Between 13% (Mahanama, 1998) and 14% (GCEC, 1991) of local households are
involved in fishing activities in the marsh area, including both fresh and brackish water parts.
Use of wetland plants and trees: Most of timber species once found in the marsh area have
now been exploited, and only small bushy plants are left (Wijeyarate, 2000), these plants are
harvested for a variety of purposes. About 60% of houses are constructed of timber plank walls,
cadjan roof and cement floor (Mahanama, 1998), and make some use of wetland species. The
vast majority of households an estimated 94% utilize wood fuel for cooking, and 60% of these
obtain firewood from the marsh area (Mahanama, 1998). Reeds and sedges obtained from the
marsh are also used for the construction of fish traps, mats and handicrafts (Wijeyaratne, 2000).
Agriculture: Due to the salinity, acidity and low natural fertility of its predominantly peat soils,
the marsh area is unsuitable for cultivating all but a very few crops (GCEC, 1991).
Recreation and tourism: The marsh area is popular recreational destination, primarily attracting
educational or school trips and day visitors from nearby Colombo. The Muthurajawela visitor
centre attracted nearly 15,000 visitors in 2000, three quarters of whom also took a boat trip into
the marsh area. It is also estimated that up to 1,500 people are employed in the hotel and
restaurant sector in the area (CEA, 1994).
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3.4 Indirect economic benefits of wetland ecosystem services
Up to 75,000 households or 300,000 people live in the Muthurajawela-‐ Negombo area, of which
an estimated 3,000 families depend on fishing in the Negombo Lagoon and a large proportion
are employed in local industries and businesses or work in Colombo. Many industries are also
located around, and upstream of Muthurajawela, including more than 100 industrial units in the
area directly adjacent to the Marsh (GCEC, 1991).
The Muthurajawela wetland system generates important indirect functions that support and
underpin industrial production and urban settlement in the area, including:
Flood attenuation: Muthurajawela receives water from rainfall, runoff from surrounding higher
grounds, and absorbs flows from the Dandugam Oya, Kalu Oya and Kelani Oya. During the rainy
season, large volumes of water enter the wetland system. The marsh plays an important
floodwater retention and buffering function by receiving and discharging these waters to the
Negombo Lagoon and the sea by way of the Hamilton Canal (CEA, 1994).
Freshwater recharge and supplies: Water is supplied to the wetland system through the Kelani
Ganga to the south of the marsh and the Dandugam Oya and Ja-‐Ela flowing through the
northern part of the marsh to into the lagoon. Muthurajawela acts as an important source of
freshwater storage (Mahanama, 2000).
Sediment and nutrient retention and wastewater purification: The marsh receives high loads
of domestic refuse, sewage and industrial wastes, and sediment and silt loads, from both
surrounding and upstream areas. It physically, chemically and biologically eliminates pollution
from these wastewaters. While wetland plants trap sediments and remove nutrients and
suspended solids, pollutants and pathogenic organisms accumulate and decompose in the
wetland’s bottom sediments, and effluents are diluted. Mangroves at the northern end of the
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marsh area also facilitate sediment deposition, before water enters Negombo Lagoon. They act
as a filter for through-‐flowing waters, and assist in the removal of nutrients and toxic
substances. These functions play an important role in assuring local water quality, and
maintaining the quality of water entering the lagoon and sea (Lucy, Kekulandala, 2003).
Fish breeding and nursery: The Muthurajawela wetland system provides indirect support to
both marsh and lagoon fish production. Its sheltered waters, flooded vegetation and mangrove
areas all constitute important breeding grounds and nurseries for freshwater and marine
species of fish and crustaceans (Lucy, Kekulandala, 2003).
3.5 Flora & Fauna of Muturajawela
Flora of Muthurajawela:
The Muthurajawela wetland sanctuary consists of a variety of seven major vegetation types:
marsh, lentic flora, shrub land, reed swamp, grassland, stream bank and mangrove forest. A
total of 194 species belonging to 66 families were recorded from the study done by IUCN during
1999-‐2000 and these included one endemic species, three nationally threatened species and 11
invasive alien species. Of the total number of species documented, 30 were woody plant
species.
Fauna of Muthurajawela:
According to IUCN study (2000) a total of 209 species of vertebrate fauna, belonging to
96 families were recorded from Muthurajawela. Of the total number of species recorded, 17 (9
%) are endemic, while 26 (12 %) are nationally threatened. Among the endemic vertebrate
species at Muthurajawela, 60% are nationally threatened.
The fish consisted of 40 species (5 endemics) belonging to 23 families, representing
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approximately 45% of Sri Lanka’s native inland fishes. Among them, 5 species are nationally
threatened, while 4 are exotic.
The amphibians consisted of 14 species (4 endemics) belonging to 4 families, including
toads, narrow-‐mouthed frogs, aquatic frogs and tree frogs. These represented approximately
26% of the total amphibian species in the island. Among them, 5 species are nationally
threatened. The Common Toad (Bufo melanostictus) and the Six-‐toed Green Frog (Euphlyctis
hexadactyla) are very common species of amphibians at Muthurajawela.
The reptiles consisted of 31 species (6 endemics) belonging to 18 families, covering 20%
of the island’s reptilian fauna. These included 15 species of tetrapod reptiles and 16 species of
serpents. Among the total species, 9 are nationally threatened. The Water Monitor (Varanus
salvator), Common Garden Lizard (Calotes versicolor), and two species of geckos (Hemidactylus
frenatus and Gehyra mutilata) were very common reptiles at Muthurajawela.
Birds appeared to be the dominant group of vertebrates at Muthurajawela, consisting of
102 species (1 endemic) belonging to 42 families. These represented approximately 37% of Sri
Lanka’s native avifauna. Among the total species were 19 winter migrants, while 3 species are
nationally threatened. About half of the bird species recorded were those associated with
wetland ecosystems, such as herons, egrets, cormorants, teals, waders, kingfishers and terns
which feed on aquatic organisms.
The mammals of Muthurajawela consist of 22 species (1 endemic) belonging to 14
families, representing approximately 25% of the island’s mammalian fauna. Among them, 4
species are nationally threatened. The murids (rats and mice) were the most common types.
The Slender Loris (Loris tardigradus) is an extremely rare primate at Muthurajawela, and it is
considered globally threatened. The marsh is also an important refuge for the carnivorous
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Fishing Cat (Prionailurus viverrinus).
3.6 Conservation measures
In 1989 as a result of growing concern about the degradation of the ecosystem, the
government froze all public and private sector developments within the marsh until the
preparation of a master plan for sustainable resource use. In 1991, the Greater Colombo
Economic Commission prepared the Master Plan for the Muthurajawela marsh and Negombo
Lagoon wetland complex, which included a land use strategy based on the wetland being
divided into zones for conservation, industrial development, and residential development. A
detailed plan for the conservation zone was prepared following approval from the government
in 1992. In 1996, 1,284.45 ha of the northern section of Muthurajawela were declared a
Sanctuary under the FFPO. In 2004, a buffer zone (the area between the conservation zone and
mixed urban zone) of 285.4 ha was protected as an EPA under the NEA. This was the first site to
be declared an EPA under this act (Lucy, Kekulandala, 2003).
4 Finding
Muturajawela wetland is facing various threats that are posed by harmful human activities
and continue to be threatened and degraded. Pressure on the wetland system arise almost
entirely from human economic activities in the surrounding area, and includes:
Habitat deterioration and degradation arising from land reclamation, clearance of
vegetation, deliberate fire, dumping of garbage, discharge of agrochemicals, industrial wastes
and organic pollution.
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Unsustainable exploitation of wild species, including tree-‐felling and use of destructive
fishing techniques or over-‐fishing of certain species or in certain areas such as to supply the
ornamental fish industry.
Introduction of alien invasive plant and animal species, including exotic fish, molluscs and
common house rat; unmanaged domestic animals such as buffalo, cats, dogs, pigs and goats;
and ornamental plants and shrubs.
Interference with wetland hydrology and ecology through the construction of engineering
works, water diversion, flood control measures and infrastructure developments such as roads
and housing.
Figure 4.1,4.2: Illegal constructions
Figure 4.3, 4.4: Tree-‐felling for use of destructive fishing techniques
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Figure 4.5: Garbage dumping
5 Recommendations
Muturajawela wetland can be identified as one of the most valuable and vulnerable
environment on which a variety of plants, animals and human communities depend. Despite its
protective statues Muturajawela is under the treat and it is necessary to take appropriate
actions to ensure the sustainable utilization of this wetland. Conservation of Muthurajawela
wetland will be a problem without public participation and lack of awareness.
A biodiversity status profile prepared by IUCN, and the conservation management plan
prepared by the CEA have made several recommendations for conservation. These include
upgrading the northern part of the Sanctuary to a higher protected area category, clarification
and documentation of the legal status of land ownership, restoration of degraded habitats,
initiation of programmes to manage the spread of invasive alien species, and rehabilitation of
the canal network to ensure adequate water seepage to keep the peaty soils moist etc.
Proposed conservation actions of IUCN, 2001 include followings:
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• According the Wetland Sanctuary status as a Ramsar site, upgrading the protected area
status of the northern part of the wetland and incorporating additional areas.
• Documenting the legal status of land within the Wetland Sanctuary, and the
socioeconomic status of communities within and around it.
• Initiating prompt action against practices that degrade the wetland.
• Initiating restoration activities to enhance degraded habitats.
• Raising awareness on the importance of the Muthurajawela wetland.
• Promoting ecotourism.
As the majority of threats to Muthurajawela are economic in origin, economic actions are
required to address them. Some of the actions proposed by IUCN, 2001 addressing economic
aspects are as follows:
• Taking action to raise awareness on the economic value of wetland conservation.
• Ensuring that wetland values are factored into development planning.
• Ensure that economic penalties are set for wetland degrading activities at a level that
reflects the economic costs they incur.
• Ensuring that wetland conservation generates tangible economic benefits for
surrounding, poor communities.
• Making efforts to capture wetland benefits as a means of financing conservation.
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6 References
Bambaradeniya, C. N. B., S. P. Ekanayake, L. D. C. B. Kekulandala, V. A. P. Samarawickrama, N. D.
Ratnayake and R. H. S. S. Fernando. 2002. An Assessment of the Status of Biodiversity in the
Muthurajawela Wetland Sanctuary. Occ. Pap. IUCN, Sri Lanka.,
CEA. (1994). Conservation Management Plan: Muthurajawela Marsh and Negombo Lagoon.
Wetland Conservation Project, Central Environmental Authority and Euroconsult, Colombo. Lucy
Emerton & L. D. C. B. Kekulandala 2003. Assessment of the Economic Value of Muthurajawela
Wetland. Occ. Pap. IUCN, Sri Lanka.
GCEC. (1991). Masterplan of Muthurajawela and Negombo Lagoon. Greater Colombo Eco-‐
nomic Commission and Euroconsult, Colombo.
IUCN Sri Lanka and the Central Environmental Authority (2006), National Wetland Directory of
Sri Lanka, Colombo, Sri Lanka.
Mahanama, P. (1998). Socio-‐Economic Baseline Survey in Muthurajawela. Integrated Re-‐ sources
Management Programme in Sri Lanka Technical Report 01, Central Environmental Authority and
Arcadis-‐Euroconsult, Colombo.
Samarakoon, J. & Renken, H. (Ed.) (1999). Wetland Atlas of Sri Lanka. Central Environmental
Authority/Arcadis Euroconsult.
Wijerayaratne, M. (2000). ‘Coastal wetland uses and related problems in Muthurajawela Marsh
and Negombo and Chilaw Lagoons’. in Farmer, N., ed. Workshop on Effective Management for
Biodiversity Conservation in Sri Lankan Wetlands: Muthurajawela Marsh, Negombo La-‐ goon
and Chilaw Lagoon. Report 55, Centre for the Economics and Management of Aquatic
Resources, University of Portsmouth.