It is dealt with in this study a one-dimensional mathematical and statistical model for acid water transport in canals including a case study in the Saigon river with data provided by Environment Protection Centre - HCM city. It is shown that based on statistical analysis of data collected in the field the computation will be improved in sense of making their solutions more reliable. | Vietnam Journal of Mechanics, NCST of Vietnam Vol. 22, 2000, No 1 (11 - 18) ON SOLUTION FOR THE PROBLEM OF SPREADING OF ACID WATER IN CANALS NGUYEN TAT DAC - NGUYEN PHI KHU Institute of Applied Mechanics, NCST of Vietnam ABSTRACT. It is dealt with in this study a one-dimensional mathematical and statistical model for acid water transport in canals including a case study in the Saigon river with data provided by Environment Protection Centre - HCM city. It is shown that based on statistical analysis of data collected in the field the computation will be improved in sense of making their solutions more reliable . 1. Introduction Pollution of water and solid environment is of critical importance, because it is difficult to control the signs of pollution and recovering time normally is very long. rhe effect of acid water plays an important role in many environmental problems, especially in living and agricultural activities. The main sources of acid water are: oxidat ion of reduced S in acid sulfate soils and discharged from coal mine operations; production of H 2C0 3 - the reactions of atmospheric C0 2 with rain water; acid rain - the reaction of 80 2 and reactive nitrogen gases NOx produces H2SOx and HN03; decomposition of litter and plant residues resulting in the formation of organic acids; mineralization of natural organic products in soil and litter. The formulation of these sources are concerned in modeling and solving acid - water problem in the southern areas of Vietnam, especially in canals and rivers. The me~hanism of acidity genesis has been presented in [1-5] . Using the jurbanite equilibrium, the governing equations for acid water in canals have been derived in [6, 7] and applied to compute the acidity for the Plain of Reeds of Vietnam. But in some extent, the assumption of jurbanite equilibrium is not strictly satisfied so statistical tests must be used before application. This paper presents an adapted solution in solving the problem of spreading of