Modelling Iniltration in A Large Scale Paddy Field in Malaysia

Prof. Dr Md. Hazrat 	Ali; Ir. Dr Ayob Katimon; Biswa Bhattacharya

Prof. Dr Md. Hazrat Ali Department of Civil Engineering, Chittagong University of Engineering & Technology
Ir. Dr Ayob Katimon Biosystem Program, School of Bioprocess Engineering, University Malaysia Perlis
Biswa Bhattacharya Department of Integrated Water Systems and Governance, UNESCO-IHE Institute for Water Education

Keywords: Iniltration Model, Iniltration Rate, Muda Irrigation Scheme, Malaysia, Paddy Field

Abstract

A number of models are available to measure iniltration in agricultural ields; however, their applicability is site speciic. It is not easy to choose an adequate model to estimate iniltration at a particular agricultural ield. In this study, ten different iniltration models have been used for the estimation of iniltration rate in data scarce Muda Irrigation Scheme, the largest paddy ield in Malaysia. The model parameters are estimated from soil characteristics, secondary data and literature. The estimated iniltration rates by the models are compared with the measured iniltration rates in order to assess the suitability of the models in the paddy ield of Malaysia. The results show that the iniltration rate estimated by physically based SmithParlange nonlinear model is very close to the observed rate. Mean monthly iniltration rate estimated by Smith-Parlange model is 0.098mm with a maximum 0.227mm during December to March and a minimum 0.005mm in May and August. All other methods are found to overestimate the iniltration rate. Though the performance of the models is assessed based on results obtained using limited data and secondary information, it is expected that the research will help select the right model to estimate iniltration, which is highly important for irrigation management especially in paddy ields.