The Nam Kam basin is located in north east Thailand, discharging into the Mekong river. At present, a hydropower project has been constructed in the basin, and Nong Han, a natural lake, is regulated for fish-production purposes. In addition, four potential reservoir sites for irrigation projects have been identified.

The water availability resulting from various combinations of project developments has been analyzed by a simulation model.

Rainfall-runoff-models were calibrated on typical subcatchments. Based on 30 years of rainfall data, a long time series of natural inflow to the various project sites was simulated. Water level variations in the reservoirs were simulated based on inflows, reservoir losses and releases. A plant-soilwater model was developed for simulation of irrigation requirements of rice paddy and upland crops.

For various cropping alternatives, the total irrigation water availability for the basin was determined under the assumption that shortages may occur in one out of five years. The simulations formed the basis for a water master plan of the basin.

For the Lower Nam Kam Project, a detailed simulation of the operation of a 14,000 ha pump irrigation project was carried out. Based on 30 years of simulated data for inflow and irrigation requirements, pumping needs and power consumption of 4 irrigation pump stations and a feeder pump station at Mekong was determined. The results formed part of the basis for the feasibility study of the project.