Reading Flow Rates

[cdock]

I've been looking at flow rates and understand that high flows do not make the best fishing conditions. What about low flows - what is too low? Also what is considered "ideal" flows - would this be steady flows for numerous days that stay constant?

[toolman]

I like the high flows that we have been enjoying this year. It's good for the fish and the insects and keeps the weeds from getting out of hand. High flows will keep the water temps. cooler and more stable in the hot dog days of summer.

I hope the high flows continue for as long as possible and continue to remain stable from day to day. The fishing on the Bow has been spectacular this season because of these conditions.

[Guest rusty]

There are 4 lines on most flow charts.

 

The blue is the current flow, the red is the average flow, and the two other (dashed) lines are the quartiles (the 25th and 75th percentiles). Note that the charts are plotted on a logarithmic scale.

 

You can get a good feel for what the conditions will be like after reading them for a while.

 

For the Bow in Calgary, I find that anything over 140-150m3/s is higher water and most fish will be on the banks. Anything under 70 will concentrate most fish in the riffles and pools. Obviously that's not a hard and fast rule.

 

Would agree wholeheartedly with Toolman though - the high water this year has made for the best stonefly fishing I've ever seen on the Bow and it really protects the river from this insane heat.

[cdock]

I do have to agree now that I think about, the fishing this season has been the best I've ever seen. Thanks guys for the tips how to read and apply the flow rates.