Nong Han
Location:	17°06'-17°15'N, 104°07'-104°20'E; extending up to 12 km northeast from the town of Sakhon Nakhon, Sakhon Nakhon Province.
Area:	12,520 ha.
Altitude:	c.150m.
Biogeographical Province:	4.10.4.
Wetland type:	14.
Description of site:	A large, permanent, freshwater lake situated among low rolling hills, and with a catchment area of 1,653 sq.km; one of the largest natural water bodies in the country. There are small areas of paddy and patches of marshland, these last totalling 750 ha. The western shore of the lake is somewhat urbanized, and the town of Sakhon Nakhon lies at the southwest corner. The main inflow is from the Nam Pung River, which runs off the Phuphan mountain range to the south. The only significant outflow is the Nam Khan, which drains southeast into the Mekong River. A spillway and two sluice gates have been installed. The average depth of the lake is l.9m and the maximum depth, 4.3m; the pH ranges from 7.0-8.4. There are considerable fluctuations in water level, with some areas around the margins drying out at the height of the dry season.
Climatic conditions:	Tropical monsoonal climate with an average annual rainfall of 1,531.7 mm. The mean relative humidity ranges from 62-80%, the mean air temperature from 23-28°C, and the water temperature from 31-34°C.
Principal vegetation:	Pistia stratiotes and Eichhornia crassipes predominate among 18 species of aquatic plants which also include Scirpus grossus, Eleocharis plantaginea, Nelumbo nucifera and Nymphoides indicum. Adjacent areas are mainly under cultivation, with some patches of scrub woodland.
Land tenure:	The lake is under public ownership; surrounding areas are mainly in private ownership.
Conservation measures taken:	None.
Conservation measures proposed:	The site has been proposed as a Non-Hunting Area.
Land use:	Fishing with gill nets, hooks and traps; cultivation of rice (one crop of wet-season rice per year) and some cassava, cotton and maize in surrounding areas.
Possible changes in land use:	This is one of the sites suggested for implementation of the Large Swamp Inland Fisheries Project, which aims to increase fish yields through stocking, dredging and manipulation of water levels.
Disturbances and threats:	The great intensity of human use probably restricts utilization of the area by waterfowl. There will almost certainly be direct disturbance of nesting species, e.g. the taking of eggs for food. Pesticide levels have not been assessed, but there may be some input of persistent organochlorines into the lake system from areas of cotton grown in nearby uplands. There may also be reduced inflow to the lake as a result of increased utilization of water upstream for irrigation and water resource projects.
Economic and social values:	Some 11,700 fishermen live around the lake and the net annual income from fishing has been estimated at Bht.h1,200 (about US$448) per household per year (Anon, 1985). The average daily catch has been estimated at 1,794 kg of which 39% is consumed locally (Jansirisak, 1977). The lake is a source of municipal water supply at the rate of 15,840 cu.m per day, supplying a total of 900,000 persons.
Fauna:	A total of 44 species of fish has been recorded (National Inland Fisheries Institute, 1980). Puntius leiacanthus predominates numerically, accounting for 20% of the total number of fish caught. The standing crop of fish has been estimated at 32 kg/ha (Anon, 1985) and 34-87.5 kg/ha (Jansirisak 1977). No information is available on the other fauna.
Special floral values:	No information.
Research and facilities:	The Sakhon Nakhon provincial fisheries station is sited at the lake.
References:	Anon (l985a); Hiranwat et al. (1977); Jansirisak (1977); National Inland Fisheries Institute (1980).
Criteria for inclusion:	1b, 1e, 2b.
Source:	Jira Jintanugool and Philip D. Round.