Measuring flow in natural channels

• weirs can be used to measure discharge rates as we did in the lab
• we can look impirically at the discharrge rate vs. height relationship for a stream without a well-defined weir and can can use this to estimate the discharge rate (Fig4.13, for this particular creek the exponent in the empirical relationship between Q and h is 2.85).
• schematic diagram of a stream gaging station (Fig5.2)
• velocity distribution as a function of depth  (Fig4.10), most flow is turbulent, average flow velocity is at a depth of 0.6*total depth
• we can measure the discharge rate by taking measurements at 0.6* depth (from surface) wading through the river (Fig4.11)
• Q = U*A = S w_i*h_i*U_i
• Small stream gaging
• Gaging larger streams and rivers
• stream gaging on the Colorado River at Lee's Ferry
• Lee's ferry, just below Hoover Dam, boats ready for trip down the Grand Canyon
• gondula used for gaging the Colorado
• steel wire crossing the Colorado at Lee's Feey and monitoring station on the other side of the river