The Thadee watershed, covering 112 km2, is the main source of water agriculture and household consumption in the Nakhon Srithammarat, Thailand. Natural forests in the watershed have been degraded and transformed to fruit tree and rubber plantations. These activities have resulted in landslide and flooding. This research predicts how furtherland-use/land-cover changes during2009–2020 and changes in rainfall scenarios may influence water yield and sediment load in the Thadee River. Local stakeholders defined t three different land use scenarios, namely trend, development and conservation. Spatially explicit empirical models were used to allocate future land demands and to assess the contributions of separated and combined effects of land use and rain fall changes. On both ecosystem services. A large expansion of rubber plantations in the uppersub-watersheds under the development land use scenario. A reduction of the current annual rainfall by 30% would decrease the predicted water yields by 38% from 2009. In constrast, an increase of 36% with respect to current rainfall would amplification of 50% of the current runoff. In addition, very high sediment load and runoff levels were predicted combination of development and use and extreme rain fall scenarios. Three conservation activities—protection, reforestation and a mixed-croppingsystem—are proposed and optimized distributed in the watershed landscape according to the allocated budget in order to have the greatest impact on watershed services of the Thadee watershed.