[Task 3] Piano-Like Gate Opening Configuration March 6~7

Task 3, piano-like gate opening configuration was tested for evenly eroded channel bed elevation along the diversion gates. Gate #23 (west side) was opened along to #1 (east side) by turns, and then back to gate #23 conversely (figure 1 and 2).

Drift velocities and water depth were measured from kayak with timer and calibrated paddle. Drift velocity was taken by getting a kayak passing time between sections.

In this stretch, up to section 4, river flows toward to the opened gate, while flows along both banks from the section 5.

Sediment deposition was evident with paddle probing next to dam gate (#9 ~ 16) on March 6. This surveying was conducted before the piano-like gate opening. However, after the gate opening (March 7), the deposited sediment was washed away and no sediment was found along all gates (figure 3).

During the gate configuration, the upstream pool water depth was usually above than 4.3 ft. Drift velocity at the fish passage was measured about 5.1 ft/s as shown in figure 4.

Figure 5 shows the drift velocities and water depths taken when the gate #22 to #11.