The lagoon has a hydro-catchment area of approximately 55 km2 (21 sq mi).2 [5] Various land use practices exist in the catchment, which mainly includes small-scale fishing industry and paddy farming.

[4] The Koggala Lagoon is one of the main features for tourists who visit southern coastal areas in Sri Lanka with rich bio diversities and eco systems.

[10] Some images include colonial rulers and strangely Queen Victoria herself to commemorate her support for local Buddhism in the face of British missionary Christianity.

However, human intervention has changed the fate of the lagoon with the destruction of the natural groyne (sand bar) during coastal defense activities in early 1990s.

However, the flow of seawater into the lagoon during the monsoon and high tides ceased the formation of sand bar again in the dry season.

Subsequently, in 1995, the Southern Provincial Council built a groyne system to protect the bridge from the wave attack.

Construction of the groyne provoked concern over local resource users and environmentalists as the lagoon hydrology and water quality showed drastic changes and variations.

Many freshwater species (Ex; Malpulutta kretseri, Etroplus suratensis) is at the risk of being prone to growth difficulties or they might even face extinction if the breeding grounds are undesirable.

[11] Fishermen who engage in Koggala lagoon claimed that their harvest of large mud crabs has decreasing due to the increased salinity as a result of the groyne construction and open mouth throughout the year.