Stream-flow forecasting by pattern-behavior

An exhaustive study of streamflow hydrographs plotted of data gathered at Cascade Locks on the Columbia River, covering the period 1886 through 1942. In the first phase of the work the graphs are classified according to type, magnitude and timing of the first 6 months of flow of the water-year, peak flow is also tabulated, and used in the ensuing forecast procedure. The second phase consists of consulting the current records to fix the probable classification, and characteristics of the current year. The third phase consists of a search for a similar year that closely matches the present year up to the time of forecasting. Several examples of the pattern forecast are shown and discussed with forecast accuracy shown. Conclusions are drawn that the procedure works well on very large drainage basins where a great variety of weather conditions are involved. The scheme may not work as well on tributary basins with relatively small areas and also a short period of records.