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 Songkhram River Basin, Thailand
Site Description

The demonstration site is contained within the area from the confluence of the Mekong and Songkhram Rivers and extends 60 km northwest up the Songkhram River, including Nam Mao and Boeng Khong Long. This area comprises almost the entire Songkhram River floodplain, which is often compared to Lake Tonle Sap. During the peak of the wet season, between June and August, the river swells to inundate marshes, ox-bow lakes, natural ponds, a number of streams and forest. One great lake is formed over the entire locale with an area of approximately 108,00ha. The inundation is for a period of 3-4 months, followed by a slow discharge into the Mekong River. The wetlands of the Lower Songkhram River were identified as nationally important in the Wetland Inventory of Thailand.

The demonstration site lies within the provinces of Udon Thani, Nong Khai, Sakhon Nakon, and Nakon Phnom. There are about 30 villages within the site, populated by approximately 20,000 people whose livelihoods are supplemented by fish and other wetland products. Many of the wetlands habitats have been disturbed through cutting of inundated forest for charcoal, clearing for agriculture, grazing, and foraging activities. Some swamps and patches of inundated forest still remain intact.

The 420km long Songkhram River has a catchment area is 12,367 square km and is the only major Mekong tributary without a large dam. The Lower Songkhram Basin is vitally important as a store of aquatic biodiversity and as a fish breeding and nursery ground for at least 17 species including the Red list species Giant Catfish Pangasianodon gigas, Tenualosa thibodeaui, Blanc’s striped Featherback Chitala blanci, Jullien’s Barb Probarbus jullieni and Thin-lip Barb Probarbus labeaminor.

Boeng Khong Long is a permanent ox-bow lake situated at the northern end of the Nam Mao, a tributary of Songkhram River. The site was declared as a Non-Hunting Area in December 1982 Boeng Khong Long and was proposed for Listing under the Ramsar Convention in April 2000. It comprises 1,103 hectares, of which 1,060 hectares is permanent water and 43 hectares is dipterocarp forest. It is managed by the Royal Forest Department, Ministry of Agriculture. Recently, a number of studies have been carried out including vegetation baseline survey, a socio-economic study and preliminary studies of aquatic plants and fish.

The main habitats associated with the Lower Songkhram River include:
Inundated forest comprising small trees, spiny scrubs and bamboo. The 153 plant species found in this habitat include Barringtonia actungula, Hymenocardia wallichii, Artabotrys spinosus, Phyllanthus collinsae and Bambusa arundinacea. In the past, large amounts of inundated forest were harvested for charcoal and cleared for agricultural purposes. The 10,000 hectares of forest still remaining is along riverbanks and scattered around lakes and marshes. The larger patches of inundated forest, ranging in size between 50–300 hectares, provide a vital nursery and breeding ground for many species of fish.
Oxbow lakes and marshlands are common on the floodplain of the Songkhram River. Over 100 lakes occur, about 51 of which have permanent water. Sedges, reeds and lotus dominate many of these areas.
Riverine channels form the backbone of the Songkhram River. The depth of these river channels varies from 2 meters in the dry season to 10 meters in the wet season. The bottom substrate is sandy soil and alluvial deposits. Occasionally rocks occur constricting flow and causing rapids.