Abstract: To further raise the application level of flood forecast information to reservoir operation, this paper examines reservoir operation schemes based on net rain forecasting through a case study of Longjiaoshan Reservoir in Shandong Peninsula. We construct a commonly-used Xin'anjiang model for this reservoir, and evaluate its errors using the method of deterministic coefficient and absolute error calculations. And the pass rate is adopted to evaluate its accuracy grading in runoff depth predictions and peak time predictions. The results show that this model features with all the evaluation indexes at grade one for both the calibration and verification periods and provides a reliable tool for reservoir operation study. Then, we formulate an operation rule for the reservoir flood control by using its predicted net rainfall information from the Xin'anjiang model, and calculate its design floods of different frequencies. Comparison of the results with those of the conventional reservoir operation shows that the forecast-based operation model, through predicting reservoir discharge in advance, can generate operation schemes that effectively reduce the peak stages and peak discharges of the reservoir and decrease its downstream flood peaks. This means a great significance to the risk reduction of flood control upstream and downstream a reservoir and the improvement on its flood control benefits.

Key words: forecast-based operation, conventional operation, flood forecasting, Xin'anjiang model, Longjiaoshan Reservoir