§378.APPENDIX C. Discharge and Travel Time Estimation

The Illinois State Water Survey, in a publication entitled, "Hydraulic Geometry of Illinois Streams," (by J.B. Stall and Y.S. Fok, WRC Research Report 15, 1968) provides a method of predicting discharge and average stream velocity in stream basins as a function of drainage area.  The equations are listed below.  Where an equation is not listed for the basin of interest, the statewide composite equations may be used.  Drainage areas can be obtained from the U.S. Geological Survey report entitled "River Mileages and Drainage Areas for Illinois Streams - Volumes 1 and 2," (by R. W. Healy, Water Resources Investigation 79-110 and 79-111, 1979).

 

Hydraulic Geometry Equations for Illinois River Basins

 

Description of Units

 

Q = discharge in cubic feet per second (cfs)

 

V = average velocity in feet per second (fps)

 

A_d = drainage area in square miles

 

F = frequency in percent of days, as a decimal

 

1n denotes that all logarithms are natural logarithms to the base

 

e = 2.718

 

Statewide Composite Equations

 

1n Q = 1.176 - 5.22 F + 0.984 1n Ad (cfs) 1n V = 0.103 - 1.81 F + 0.158 1n Ad (fps)
Rock River	Des Plaines River
1n Q = 0.24 - 3.50 F + 1.03 1n Ad 1n V = 0.20 - 1.50 F + 0.13 1n Ad	1n Q = 1.78 - 4.98 F + 0.90 1n Ad 1n V = 0.26 - 1.31 F + 0.08 1n Ad
Galena River	Kankakee River
1n Q = 0.13 - 2.27 F + 0.96 1n Ad 1n V =-0.06 - 0.81 F + 0.06 1n Ad	1n Q = 1.41 - 5.12 F + 0.96 1n Ad 1n V =-0.38 - 1.19 F + 0.17 1n Ad
Fox River	Vermilion River (Illinois River Basin)
1n Q =-0.24 - 3.33 F + 1.13 1n Ad 1n V = 0.11 - 1.39 F + 0.16 1n Ad	1n Q = 0.97 - 6.28 F + 1.01 1n Ad 1n V =-0.20 - 2.19 F + 0.17 1n Ad
Mackinaw River	Kaskaskia River
1n Q = 1.39 - 7.52 F + 1.00 1n Ad 1n V = 0.38 - 2.26 F + 0.09 1n Ad Henderson Creek	1n Q = 0.95 - 5.88 F + 1.02 1n Ad 1n V =-0.26 - 1.28 F + 0.14 1n Ad Vermilion River (Wabash River Basin)
1n Q = 1.44 - 5.00 F + 0.89 1n Ad 1n V = 0.58 - 1.76 F + 0.01 1n Ad	1n Q = 1.11 - 4.96 F + 0.98 1n Ad 1n V =-0.81 - 2.20 F + 0.29 1n Ad
Spoon River	Embarras River
1n Q = 0.86 - 4.82 F + 1.00 1n Ad 1n V = 0.52 - 1.63 F + 0.08 1n Ad	1n Q = 0.04 - 5.61 F + 1.17 1n Ad 1n V =-0.92 - 1.62 F + 0.26 1n Ad
LaMoine River	Little Wabash River
1n Q = 1.03 - 5.60 F + 0.92 1n Ad 1n V =-0.13 - 1.16 F + 0.11 1n Ad	1n Q = 1.91 - 7.90 F + 0.96 1n Ad 1n V =-1.38 - 1.18 F + 0.30 1n Ad
Sny River	Big Muddy River
1n Q =-2.27 - 5.87 F + 1.63 1n Ad 1n V =-1.29 - 1.06 F + 0.39 1n Ad	1n Q = 1.26 - 8.50 F + 1.09 1n Ad 1n V =-0.75 - 1.47 F + 0.18 1n Ad
Sangamon River	Big Bay Creek
1n Q = 0.65 - 4.93 F + 1.03 1n Ad 1n V =-1.01 - 0.95 F + 0.26 1n Ad	1n Q = 1.48 - 7.90 F + 1.05 1n Ad 1n V =-0.53 - 0.41 F + 0.14 1n Ad