... Journal of Water and Environment Technology, Vol. 6, No.2, 2008 - 93 - Frequency of Routine and Flooding-stage Observations for Precise Annual Total Pollutant Loads and their Estimating Method in the ... transverse points over the river during five periods of flooding in the routine observation period. The frequency of flooding-stage observations was set close interval before the flow peak and thereafter ... those in the rainy year of 2004. Therefore, a precise estimation of annual total pollutant loads, even for a large stable-flow river, is required using both frequent routine observations and continuous...