In savanna and tropical monsoon areas where the dry and rainy seasons can be clearly distinguished, it is important for farmers to secure as much irrigation water as possible in the dry season in order to produce fruits and vegetables. Though the Department of Land Development, Ministry of Agriculture and Cooperatives, Thailand recommends that farmers excavate small farm ponds for the purpose mentioned above, the irrigation water stored in the farm ponds in the rainy season is not effectively used in the dry season because of evaporation from the surface of water and percolation from the bottom and lateral parts of the ponds. Therefore, the authors developed methods to control the evaporation and percolation in small farm ponds. They selected 4 methods mentioned below, based on the results of experiments carried out in the eastern region of Thailand by Kobayashi. They developed low cost and sustainable methods which farmers can apply themselves as follows: (1) Covering the surface of water with floating materials. (2) Management of irrigation water using several ponds. (3) Changes in the pond shape. (4) Compaction of the bottom of the pond after crushing. The authors confirmed the effectiveness of the 4 methods through field experiments and model calculations.