THE COMPUTER PROGRAM 



The program consists of three sections: 

 Input of basic data (lines 1 through 12); anal- 

 ysis of data (lines 13 through 129); and output 

 of results (lines 130 through 183). 



Input of Basic Data 



The program is designed to accommodate 

 data for 1 year, providing the time interval be- 

 tween readings is not less than 1 hour and the 

 number of storm events is not more than 300. 

 The dimension statements should be changed 

 if the number of data points exceeds 9000 or 

 the number of anticipated storm events ex- 

 ceeds 300. If either of these conditions ap- 

 plies, the author suggests that less than a 

 year's data be analyzed at one time. 



The "read" statement should fit the for- 

 mat in which the input data are punched on 

 the cards. In this program, there is no "read" 

 statement for hour, because all hydrograph 

 readings were taken at 1-hour intervals. If a 

 variable time interval characterizes the input 

 data, then a new "read" statement should be 

 made. 



Analysis of Data 



1. Volume parameters 

 Total flow 



Base flow 

 Storm flow 



Interflow 



Rapid flow 



2. Time parameters 



Hour at which event starts 

 Hour at which event peaks 

 Hour at which event ends 



Number of hours from start to peak 

 Number of hours from peak to end 

 (recession time) 



3. Rate parameters 

 Initial stream flow rate 

 Peak rate 



Final rate 



4. Angle parameters (in radians) 



Rising angle (formed by intersection of 

 horizontal line and line connecting ini- 

 tial and peak rates) 



Recession angle (formed by intersection of 

 a vertical line and line connecting peak 

 and final rates) 



Top Angle (formed by intersection of line 

 connecting initial and peak rates with 

 line connecting peak and final rates) 



Base angle (formed by intersection of hori- 

 zontal line and line connecting initial 

 and final rates) 



5. Line parameters 



Base line (length of line connecting initial 

 and final points of the storm hydro- 

 graph) 



Perimeter (sum of lines connecting initial, 

 peak, and final points on the storm 

 hydrograph.) 



6. Ratio parameter 



Ratio of perimeter to natural logarithm of 

 1.0 + stormflow) 



The relation between stage and flow rate 

 (cubic feet per second) is unique to each type 

 of waterflow-measuring installation. Hence, 

 the user of this program must supply the cali- 

 bration equation that applies to the installa- 

 tion. This is done in lines 23 and 24, and also 

 in lines 38, 39, and 56. In addition, the user 

 must indicate the area of the watershed in 

 acres (line 164). 



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