COHSTREX 2005 Jetty Island Field Experiment


This reporting period was preparation for and execution of the preliminary experiment that took place from 17-22 July 2005. The following tasks were accomplished during the preliminary experiment (click on the links to learn more):

In conjunction with the preliminary experiment, modeling work accomplished included analyzing the tidal forcing for boundary conditions and work on sediment transport technology.

The location of the preliminary experiment on the Snohomish River in Everett, WA is shown in the satellite photograph in Figure 1a. The photograph in Figure 1b shows the rock sill that is exposed at low tide and forms a gap with the north tip of Jetty Island through which the river flows. Figure 2 shows the deployment of IR and video cameras and the RiverScat scatterometer from an aerial lift on a spud barge positioned at the north tip of Jetty Island. The RiverRad pulsed, scanning radar used to map surface roughness and velocity is shown in Figure 3a and the jet boat used for the ADCP measurements is shown in Figure 3b.

Figure 1. (a) Satellite image of experiment site on the Snohomish River at the N. tip of Jetty Is. (*). (b) Photograph taken from barge (See Figure 2) near the north tip of Jetty Is. looking east during ebb tide. As the tide ebbs, the rocky sill in the middle of the photograph becomes exposed. A gap through which the river flows is formed by the western edge of this sill and Jetty Is., visible in the bottom-middle part of the photograph. The large blue arrow indicates the direction of flow through the gap. The location of RiverRad on the far bank of the river (cement plant) is indicated.

Figure 2. Photograph showing aerial lift on the spud barge at the north tip of Jetty Island used for the IR, video, and RiverScat measurements. The inset photograph shows the sensors mounted in the aerial platform. The sill, gap, and north end of Jetty Island are indicated.

Figure 3. (a) RiverRad pulsed, scanning radar for mapping surface roughness and velocity located at the cement plant on the bank across the river from Jetty Island (See Figure 1b). (b) APL Jet boat with ADCP mounted on port side used for bathymetric survey and velocity profile measurements.

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