Drainage: ~280 sq.mi.

Our listed put-in is actually on Spring Brook, a tributary of the Eau Claire, with 66 square mile drainage.

Combined drainage area at the confluence with the Eau Claire is about 280 square miles.

By our listed take-out it is 295 sq.mi. (an increase of just over 5%).

At the gauge (a long ways downstream of these whitewater sections of river), drainage is listed as 375 sq.mi.

Thus, flow at the confluence of Spring Brook and Eau Claire might be expected to be very nearly 3/4ths that gauge reading.