Output of Results 



Summaries of results of all analyzed storms 

 are tabulated in a series of tables (see Ap- 

 pendix 1) and also on cards. (See Appendix 2, 

 lines 173 and 174, for format.) 



Appendix tables 1 through 5 are examples 

 of the program printout. Tables 2-5 are sum- 

 mary tables of all the storms analyzed. Table 

 1 (Appendix 1) is a detailed analysis of each 

 individual event, and requires some explana- 

 tion. The sample printout is an analysis of a 

 short storm during October 1968 on the East 

 Fork of Horse Creek in north central Idaho. 



The storm started at hour 347 when 

 streamflow rate was 4.139818 c.f.s. (Six deci- 

 mals are printed to enable the hydrologist to 

 analyze any portion of the event without loss 

 of accuracy due to rounding-off procedures.) 

 The storm ended at hour 361.92 when 

 streamflow rate was 4.335419 c.f.s. Column 2 

 shows the rate of flow (c.f.s.) at hourly inter- 

 vals along the base flow line — the line sepa- 



rating base flow from stormflow. The third 

 column ("runoff rate") shows actual stream- 

 flow rate (c.f.s.) at hourly intervals. This 

 figure is the input data (stage-in feet) con- 

 verted to c.f.s. The last column (interflow 

 rate) shows the rate of flow (c.f.s.) at hourly 

 intervals along the line separating interflow 

 from rapid flow. As long as values in this col- 

 umn are smaller than those in the "runoff 

 rate" column, the rapid flow separation curve 

 has not crossed the hydrograph. When rapid 

 flow has ended, then the figures in the last 

 column are identical with those in the "runoff 

 rate" column. In this example, rapid flow 

 ended between hours 353 and 354. Total flow 

 from hour 347 to hour 361.92 was 

 68.413391 c.f.s. -hours (column 5), of which 

 63.696930 was base flow (column 4) and 

 4.716461 was stormflow (column 7). Storm- 

 flow amounted to 6.89 percent of the total 

 flow (column 6). Other figures in table 1 as 

 well as in the summary tables are self ex- 

 planatory. 



USES FOR THE COMPUTER PROGRAM 



Hydrograph analysis is a difficult and 

 time-consuming operation. The inherent dif- 

 ficulties have forced hydrologists to limit 

 their analysis to a few extraordinary hydro- 

 logic events, or to events that they believe 

 represent average conditions. 



By using this computer program, the 

 hydrologist can analyze all streamflow 

 events — rainstorms, snowmelt events, and 



even daily events resulting from excessive 

 evapotranspiration. Any event, regardless of 

 its cause, can be analyzed automatically, and 

 can be recorded in a condensed form. The 

 computer program enables the hydrologist to 

 readily compare the numerous elements of 

 hydrologic events occurring on two or more 

 watersheds, because they are recorded in 

 orderly form. 



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