M-TROPICS/MSEC is the network of three agricultural headwater catchments representative of the sloping lands of South-East Asia (Laos, Thailand, and Vietnam). It was launched in 1998, and started collecting data since 2000 on climate, land use, agricultural practices, stream discharge, suspended and bedload sediment yields.
The 93.2 ha Huay Ma Nai catchment is located in northern Thailand, in the Phrae Province. Elevation ranges from 380 to 490 m above sea level and slopes range from 15 to 65%. Huay Ma Nai catchment is included in the Maethang watershed (121 km²).