Farms in Northeast Thailand suffer often from droughts in the dry season and sometimes even in the rainy season. The reason is that much of the ample annual rainfall is not retained on the farms. A recent movement to construct ponds on farms increased the capacity to store water in a significant manner. It was observed that on homesteads with ponds, pond water was used for many purposes: mainly to irrigate crops and fruit trees, and for livestock or fish, and even in homes when water from cleaner sources was unavailable. With more diverse and productive activities, homesteads with ponds produce nearly all food they need, and probably enjoy a slightly higher income than those without ponds. Pond water is used even when ample piped water is available.
The optimal size of a farm pond depends on biophysical factors (weather, soil, crops) and even more on socioeconomic factors (prices, availability of labor, off-farm income). The aspirations of the household, expressed in goals and limitations, are also very important. It is argued that a simulation approach is required to help produce guidelines for construction of ponds on individual homesteads. The model BoNam outlined here comprises an integrated water balance of the plots on a homestead and the pond, and can simulate the consequences of various scenarios. Some results are presented in this paper.
A climate similar to that of Northeast Thailand is found in many tropical countries. Approaches to improve smallholder farming with ponds using information from this paper may be useful in other countries with pronounced wet and dry seasons.
Penning de Vries, F.; Ruaysoongnern, S. Multiple sources of water for multiple purposes in Northeast Thailand. (2010) International Water Management Institute, Colombo, Sri Lanka 37 pp. ISBN 978-92-9090-725-1 [DOI: 10.3910/2010.208] IWMI Working Paper 137