Malala-Ambilikala lagoons are two interconnected coastal water-bodies located inside the Bundala National Park, Hambantota District in the Southern Province, Sri Lanka. It is from Colombo to the arid south. The Malala-Ambilikala lagoons are two of the three key lagoons located within the Bundala Ramsar wetlands.
Features
The Malala – Ambilikala lagoon system is the main lagoon system situated in one of the three Ramsar sites within Sri Lanka, the Bundala National Park. The two lagoons are interconnected by a long, meandering incised channel called ‘Ooday’ in Sinhalese. Both the Malala and Ambilikala lagoons are shallow water bodies with average depths of and respectively. The water surface area of the Malala and Ambilikala lagoons are and respectively. While the Ambilikala lagoon is an inland freshwater lagoon with no direct outfall to the sea, the Malala, as its name implies, is a lagoon which has a direct connection with the Indian Ocean at the Malala sea outfall. Inputs to the Ambilikala and Malala lagoons include agricultural drainage, runoff with cattle refuse, and salt water when the sand bar between the Malala Lagoon and the sea is breached. Malala lagoon receives freshwater from Malala Aara, Heen Aara and Palalgawala Aara streams, surface drainage and overflow from Nadada wewa tank. The main freshwater supplies of Ambilikala lagoon are streams such as Weligatta Aara, Sundiram Aara, Ethuklbokka Aara, Right Bank Channel of the Lunugamvehera Reservoir, Kirindi Oya Irrigation and Settlement Project, and surface drainage and overflow from tanks such as Bandagiriya, Keligama wewa, Julgamuwala wewa, Arabedda, Udamalala wewa. The total hydro-catchment of the lagoon system is about.
Environmental problems
The hydrological, ecological and biological condition of the Malala and Ambilikala lagoon systems started to change rapidly with irrigation, agriculture, and human settlements in the upstream area, especially water quality problems affected the functioning of the lagoon ecosystem. The Kirindi Oya Irrigation Settlement Project expanded the irrigation area from to during the early 1990s which located upstream of the Bundala National Park. The Malala and Ambilikala lagoons were severely affected by the modified drainage flows from the Kirindi Oya Irrigation Settlement Project and the Bandagiriya irrigation scheme. The estimated monthly load of total nitrogen and total phosphorus in to the Malala-Ambilikala lagoon system from the agricultural drainage were and respectively. An extinction of species and changes to habitat diversity were also observed in the lagoon system due to water quality changes. In addition to that, Increasing inflows and decreasing salinity in the lagoon water has caused severe socio-economic problems to the people who relies lagoon resources for livelihoods. A decline in shrimp and new fish species with less commercial value were observed due to a significant decrease in salinity levels.
Research
A number of studies have been carried out recently on ecohydrology and socio-hydrology of the Malala and Ambilikala lagoons.
