Abstract
In this paper, using 10-minute resolution discharge data and water quality data, which are derived from 15-minute resolution data using linear interpolation, the certainty of estimated effluent load for about six-month period is discussed using a variety of estimation method. The analyzed indices are chloride, potassium, and sodium. Firstly, the effect of cycle of regularly-interval sampling on the certainty in estimated load are evaluated, using simple average method, discharge-weighted average method, powered type LQ regression method, and linear LQ regression method. Secondly, the effect of sampling method on effluent load during individual rainfall-runoff event was also evaluated. Finally, using ΣL-ΣQ method and L-R method, the total effluent load of all rainfall-runoff events is calculated and the evaluation of certainty is also carried out. As results, linear LQ regression method gives the best estimated value in certainty. The discharge-weighted sampling method is better than the regularly sampling method in the estimation of the event load. Estimation of certainty of estimating total effluent load of all high flow periods by L-R method and ΣL-ΣQ method using the small number of event data, such as 5 to 6 events data for six months, doesn't contribute to the improvement in certainty compared with linear LQ regression method using weekly cycle sampling data.
