Gregory’s Lake

Location: 60 57’ 0 N and 800 45’ 0 E to 60 56’ 0 N and 800 48’ 0 E; 768229 N and 472384 E to 766384 N and 477907 E; within the municipality area of the city of Nuwara Eliya; Nuwara Eliya District; Central province.

Area: The area of the Gregory’s Lake is 0.4 km2 with a perimeter of about 3.5 km.

Altitude: 1,914 m above MSL

Overview: This is a man-made tank, named after Sir William Gregory, Governer of the then Ceylon from 1872 to 1877. The swamp, which existed at this location, was converted into the water body of the Lake Gregory by damming Nanu Oya stream. This is a unique artificial wetland created in the heart of the high altitude city of Nuwara Eliya. It is located just 610 m below the Pidurutalagala peak, which is the highest peak in Sri Lanka. The Lake is bounded on all sides by roads, and the surrounding area has been severely altered by agricultural expansion, and urban sprawl. Because of the Lake’s aesthetic value and scenic attraction, many holiday homes and tourist hotels have been established around it.

Physical features: Lake Gregory is a small, man-made Lake, located in the wet montane zone of Sri Lanka. A major tributary of this Lake is the Nanu Oya stream that originates from the Pidurutalagala Peak. Nanu Oya receives many small tributaries on its downhill journey to the Lake. Most of the streams in the catchment area have been changed over the years for commercial agriculture developments. These agriculture developments and tourist expansions are threatening the future of the present day Lake. Lake Gregory receives an average annual rainfall of 2,000-2,500mm, and a mean annual temperature of approximately 16oC. The underlying area of the Lake consists of highly crystalline charnockitic genesis rocks of Precambrian age.

Ecological features: Major habitat types around the Lake area include freshwater marshes, streams, degraded montane forests and agricultural lands (tea plantations, vegetables cultivations etc.). The aquatic vegetation in the Lake consists of phytoplankton, and rooted macrophytes. The fauna recorded from the Lake environs include 11 species of invertebrates and 77 species of vertebrates.

Noteworthy fauna: The freshwater fish populations in the Lake consist entirely of exotics, dominated by Oreochromis spp. and Cyprinus spp. Among the aquatic amphibians, the endemic Polypedates eques and Lankanectus corrugata inhabit the streams and marshes around the Lake. Aquatic birds that visit the Lake include cormorants (Phalacrocorax niger), egrets (Egretta garzetta, Mesophoyx intermedia), herons (Ardeola grayii) and kingfishers (Alcedo atthis, Halcyon smyrnensis), while raptors include Elanus caeruleus and Circus spp. Among the mammals, Lutra lutra and Prionailurus viverrinus inhabit the surrounding environs. The riparian areas and associated streams harbour several endemic crab species (Perbrinkia spp. and Ceylonthelphusa spp.).

Noteworthy flora: The phytoplankton communities are dominated by Myxophyceae (blue green algae). The floating macrophytes in the Lake are dominated by two exotic species; Salvinia molesta, and Pistia stratiotes. The other rooted aquatic plants that are common in the Lake include Hydrilla verticillata, Nymphaea spp., and Cabomba sp. Predominant plant species in the Lake bank include Aristea eckloni, Pogostemon reflexus, Eriocaulon brownianum, and Osbeckia parvilolia.

Land use: The surrounding environs consist of marshes, home gardens, vegetable cultivations, tea plantations, hotels and commercial centers.

Possible changes in land use: Reclamation of the lake area for commercial agricultural expansion, and human settlements are the major land use changes expected.

Hydrological and biophysical values: The water from Lake Gregory is predominantly used for irrigating green houses and other horticultural activities, particularly during the dry season. The general perception of the local community is that the water in the lake is not very clean as a result of stagnation and due to the large amount of dissolved agro chemicals.

Social and cultural values: The Lake serves as an aesthetic and recreational site for visitors to Nuwara Eliya. The water within the lake acts mainly as a supply for the surrounding agricultural lands during the dry season and not as a source of potable water for the town residents. Domestic tourism is an important component of the local economy.

Scientific research and monitoring: No research facility exists at present.

Conservation education: University students are taken to this site for courses on water quality testing.

Recreation and tourism: Although there are many tourist hotels in the area surrounding the lake, it is not the sole attraction for visitors to the area. The municipal council leases out permits for boat operators to make boating available to visitors. The CTB in its Tourism Master Plan proposes to introduce recreational facilities at the Lake Gregory.

Conservation measures taken: The CEA produced a conservation management plan for this site in 1997. Additionally, a small patch of forest bordering the Lake was recently declared as a protected area under the DWC. In the Nuwara Eliya Urban Development Plan, unsuitable agricultural activities on slopes have been prohibited in order to reduce erosion and subsequent silting of the lake.

Conservation measures proposed: Major threats to Lake Gregory include the reclamation of the Lake area for commercial agricultural expansion, expansion of human settlements and the subsequent increase in pollution. The rapid and uncontrolled increase in invasive plant species (e.g. Salvinia molesta, Pistia stratiotes, Eichhornia crassipes) is also threatening the beauty and ecological value of the lake. The unregulated application of agrochemical and organic manure has already changed the water quality of the lake. Accumulation of heavy metal in the Lake is inevitable unless regular flushing is carried out. Need urgent actions to mitigate existing threats.

Disturbance and threats: The Lake is state owned while the surroundings are both privately owned and state owned.

Land tenure: The Lake falls under the jurisdiction of the Nuwara Eliya Municipal Council while the UDA is responsible for zoning and for the development of regulations, and has prepared a Recreation Master Plan for this wetland and its surrounds. Although a major dredging programme was carried out by the UDA some years ago, responsibilities related to its maintenance lie with the Municipal Council.

Management authority and jurisdication: CEA/ARCADIS Euroconsult (1997a); Pradeep Samarawickrema (personal communication)

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