Improving water supply forecasts by limiting techniques

Water supply forecasts computed by objective procedures can be improved by modification prior to release by using methods based on several relationships. These techniques identify the forecasts which have a great probability of large errors and provide a basis for subjective quantitative adjustment. The relations are (1) adjacent basin plots, (2) carryover plots, (3) comparisons with auxiliary procedures of basically different derivations. The value of the method suggested increases in the unusual or abnormal year and tends to eliminate the possibility or reduce that magnitude of the 'big bust'.In discussion Mr. Harry I. Hunter cautions against using only procedure or independent variable for developing a water supply forecasting formula, and states that combination of variables may produces a more accurate and a better balanced forecast.