Table 12. Instream flow recommendations (cfs) for German Gulch at the Below 

 Beef straight Creek study site compared to the 10th, 50th and 90th 

 percentile monthly flows (cfs) . 



Percentile Flow (cfs) 



Time Period 



January 



February 



March 



April 



May 1-15 



May 16 - 31 



June 1 - 15 



June 16-30 



July 



August 



September 



October 



November 



December 



Recommendations (cfs) 



12 

 12 

 12 

 12 



12 2 



53 2 

 58 



12 



12 



12 



12 



12 



12 



12 



I 



10th 50th 90th 

 ( Wet Year ) ( Typical Year ) ( Dry Year ) 



109. A 



150.1 



64.0 



70.5 



41.3 



43.3 



Derived using the wetted perimeter/inflection point method and the dominant 

 discharge/channel morphology concept. 



Plus the dominant discharge of approximately 139 cfs, which should be main- 

 tained for one 24-hour period during May 16 - June 15. 



Derived by the USGS using recorded and reconstituted flows at the gage site 

 on German Gulch located 0.5 miles upstream from the mouth (No. 12323500), 

 1951 - 1982. 



The 10th percentile is the flow that is exceeded in 1 of 10 years; in other 

 terms, in 1 year out of 10 there is more water than the 10th percentile 

 flowing in the stream. 



The 50th percentile is the flow that is exceeded in 5 of 10 years; in other 

 terms, in 5 years out of 10 there is more water than the 50th percentile 

 flowing in the stream. 



The 90th percentile is the flow that is exceeded in 9 of 10 years; in other 

 terms, in 9 years out of 10 there is more water than the 90th percentile 

 flowing in the stream. 



38- 



