This Continuing Multi-Year (CMY) project, now in its last year, has two main goals: 1) to investigate how water quality in headwater streams in Montane Mainland Southeast Asia will be affected by plausible changes in both climate and land-cover/land-use through a field study in Thailand; and 2) to develop capacity to conduct similar studies in China, India, and Viet Nam. A year-long study of dissolved and particulate phases of sediment, carbon, and nitrogen was conducted in Mae Sa Basin, Thailand; whereas a flood sediment deposition study was carried out on an inundated area along the Ping River, which drains the Mae Sa Basin. In China, a carbon and sediment monitoring campaign at Chu Xuong in the Dali region of Yunnan Province was initiated. The runoff and sediment on the Gundal River in Southern India were monitored, while a study of regional water and carbon cycles in the context of human-environment interaction in a section of the Lower Mekong River, near Chau Doc, started in Viet Nam. The project is generating new data regarding the potential effects of climate change, which is important for developing sound mitigation strategies, as well as determining non-linear vulnerabilities of natural and human systems.