Shifts are applied by developing “V-diagrams”

Channel Cross Section Shifts are applied by developing “V-diagrams” Recent Measurements Measurements plotted on axes of V-diagram

Channel Cross Section Here is what a v-diagram and its shift curve generally look like Shift curve Variable shift diagram

Shifts vary by STAGE and TIME Sept. 1 July 1

Shifts should be faithful to the base rating Meas. made 7/20 and 8/15 Sept. 1 July 1

Let’s follow an application of shifts at a site Recent Measurements Concrete Control

It would be easy (but WRONG) to lump all measurements into one shift---- 4 5 6 3 2 1 4 6 3 5 2 1

One shift doesn’t always work Channel Control Section Control

You need to consider the hydrograph when applying shifts

Let’s see how all the available information should be put together Algae growth? Channel Control Section Control

Changes in the channelcontrol caused the rating to shift Upstream view of control at GH of 5.40 feet Channel Control Downstream view of control at GH of 6.25 feet

Measurements were used to define two shift curves V-diagram representing channel control 4 V-diagram representing section control 5 6 3 2 1

Shift application took the hydrograph into account Effective from ???? Effective from ???

Hold Scour Fill Here is a generalized example of how shifts can be timed Prorate X #3 #2 X #1 X X=Discharge Measurement

Shifts are applied by developing “V-diagrams”