The data displayed in the above graph is generated by averaging the stage height of the canal flume once per minute over a period of one hour. The hourly average flow (or discharge) is then calculated by looking up the flow, based on stage height, in the station’s weir rating table.
Diurnal (daily) fluctuations may show up in these graphs. This is likely related to the water consumed by the plants/trees in the riparian zone. Each day when the sun begins to shine the streamside vegetation lowers the water table. Since there is less water in the system available for diversion when this occurs, a drop in the water flows in the canal diversions shows up in the graphs. The delay in the lowering of water flows is caused by the time it takes to deplete, and refill, the water table each day.