In contemporary Sri Lanka, urban wetland eco-systems could generate a wide spectrum of its services in the face of a growing demand for recreational opportunities and amenities from the urban residents. Diyawanna Oya wetland, which is already proved to be an important recreational site in the greater Colombo area, is prone to severe threats from illegal reclamation and constructions for urban development purposes. The value of Diyawanna Oya wetland is threefold; first, it provides a good recreational ground for exercise, sports and family outings; second, inhabitants in surrounding areas use this as a source of income from fishing, cattle grazing, collecting reeds, rushes and fuel wood; and finally, from the environmental point of view, this wetland constitutes an important flood retention area and a rich habitat of indigenous fauna and flora. Thus, it contributes significantly to the social well-being of the urban and sub-urban society. None of these use or non-use values of Diyawanna Oya site has been recognized adequately and instead, dumping of garbage and reclamation of land in this area have become serious threats at present.

This study attempts to estimate the economic value of this natural resource based on the perceptions of the regular visitors of the site on the recreational value and their preference to conserve this endangered and under-appreciated resource using the Travel Cost Method (TCM). The findings indicate that the Diyawanna Oya wet lands generate an annual consumer surplus of Rs. 3,890 million to people who use the area for recreation. The welfare loss from converting the natural wet land area to development projects is Rs. 19.45 million per hectare which is equal to Rs. 49, 246 per perches. The study highlights the need for more to be done to conserve the wet lands and suggests a number of ways of generating revenue that could be used to fund wet land conservation and enhancement.