A Coastal wetland of Natural origin located in the Wet Zone of the Western province. Muthurajawela is the largest saline peat bog in Sri Lanka, and together with the Negombo estuary forms an integrated coastal wetland ecosystem spanning 6,232ha. The location of Muthurajawela in a rapidly developing and highly populated urban area makes it an extremely valuable, yet vulnerable ecosystem. The marsh is located in the low country wet zone and influenced by the southwest monsoon. The marsh plant community is unstable and represents one of the final stages of succession towards dry land formation. 194 species of flora (66 families) are distributed over seven major vegetation communities (marsh, lentic, reed swamp, short grassland, shrub land, stream bank and mangrove swamp). The shrub land harbours the highest number of species (115), while the mangrove forest and stream bank/riparian type consist of the lowest (23). The vertebrate fauna includes 40 species of fish (4 endemic and nationally threatened), 14 amphibians, 31 reptiles, 102 birds (one endemic and 19 winter migrants), and 22 species of mammals. Of the 209 species of vertebrate fauna documented, 17 are endemic, while 26 are nationally threatened. Of the recorded flora, one is endemic (Phoenix zeylanica), and three nationally threatened (Aponogeton natans, Nypa fruticans, Caesalpinia crista). The mangroves in the northern border of the marsh are dominated by Avicennia marina and Rhizophora mucronata. The lentic flora in open water bodies is dominated by Nymphaea stellata and Eleocharis dulcis. The riparian vegetation includes Pandanus tectorius, Cerbera manghas and Syzygium caryophyllatum. The reedbeds consist of Phragmites karka. The canals running through the wetland were developed and used for transportation of goods during the Dutch period. Recently the marsh was segmented due to the construction of the Colombo-Katunayake highway.

Muthurajawela Marshes Related references