0023-6152

AA00697606

24319

Unrefereed

0023-6152

AA00697606

The study aimed to investigate the characteristics of net water requirement and the gross water requirement of paddy field irrigation in diversified land use area. The net water requirement, which is the net quantity of water demanded in paddy plot, is clarified using the tank model. The tank model consisted of 6 sub tank i.e., irrigation canal tank, paddy tank, upland tank, settlement tank, greenhouse tank and drainage canal tank. The main purpose of using the tank model is to find out the acceptable values of outflow from each sub tank model. Results based on 4 years historical data depicted that the paddy fields yielded the dominant discharge compared to other land use type. The quantity of net water requirement of paddy fields was obtained using the acceptable of the tank model. Furthermore, the deep percolation and surface runoff from paddy fields were the dominant component of the net water requirement. The acceptable of the tank model was applied for predicting the gross water requirement. Intake water from Yamada weir of 1998 named as observed gross water requirement was used for simulating the gross water requirement. Results showed that the observed gross water was slightly higher than the simulated gross water requirement. The simulated gross water requirement recommended as reference for deciding the gross water requirement in this area because of its efficiency. And the reasonable of simulated ponding depth also snpported the result. Furthermore, the results of numerical treatment of gross water requirement showed that the application of the gross water requirement of 5 m^3/s was reasonable compared to other treatment.