Figure 1. View from inside North Head Lighthouse with cameras in the foreground and Cape Disappointment (formerly Fort Canby) State Park, Benson Beach, and the north jetty of the Columbia River mouth in the background.	Figure 2. Satellite map of the region of interest. The black arrows radiating from North Head mark the merged view of the eight ABMS video cameras.

Shallow Water Site Images

Four cameras (numbered 1 - 4, west to east) are used to view the Shallow Water Site (SWS) and the MCR Bar; camera 1 captures the western edge of SWS, camera 4 captures the eastern edge. High power lenses (50mm) are used to capture the presence or absence of wave breaking in the field of view between North Head and the SWS.

(Disclaimer: The quality of all these pictures is subject to weather conditions. In addition, these snapshots can only capture a moment in time and therefore are not absolute indicators of the presence or absence of wave breaking.)

SWS Snapshot Images - Updated every 20 minutes
( 28 Aug 2008 06:20 PDT )

Camera 4	Camera 3	Camera 2	Camera 1

The red dots in the snapshots mark the known location of buoys. The yellow line indicates the boundaries of the SWS. Because the cameras move during the day with the heating and cooling of the lighthouse cast-iron superstructure, these locations will be off by as much as 200m Northing (and 20m Easting). This camera movement is corrected in post processing of cameras 5, 6, and 7. Time stamps on the images are in Pacific Standard Time. Click on an image to enlarge it.

SWS Plan-View - Updated hourly
( 27 Aug 2008 21:15 PDT)

This plan view image is derived from the 10-minute time-average video clips of Camera 1,2,3, and 4 (see their snaps above). This plan view image is updated hourly whereas the snap images above are updated every 20 minutes. The yellow box outlines the location of the SWS with red dots marking the nominal location of buoys. Significant wave breaking in a time-averaged image is identified as white regions.

Benson Beach Images

Four cameras (numbered 5 - 8, west to east) are aimed along Benson Beach, designed to span from the western tip of the north jetty shoreward to the beach and adjacent dunes and grasses. Camera 8 uses a 16mm lens to give an overview of the beach and jetty, while higher power 50mm lenses are used on cameras 4 - 7 to better resolve shoreline and sandbar location changes, and to evaluate waves and currents along this 3km stretch of beach and surf zone.

Images of Benson Beach are acquired every hour. The most recent snapshots are displayed below.

Benson Beach Snapshot Images - Updated hourly
( 28 Aug 2008 05:31 PDT )

Camera 8

Camera 7	Camera 6	Camera 5	Camera 4

Example Image Products

These individual camera images can be combined using photogrammetry methods to generate panoramas and rectified plan view images –

Figure 3. Panoramic image of 10-minute time-average video acquired from cameras 1 through 7 on 27 September 2005 at 2200 GMT (1400 PST). Click the image for a larger version.

Figure 4. Rectified plan-view image of Figure 3. Coordinates are in local Argus coordinates. North Head Argus coordinate system is related to Wa South Zone State Plane NAD83 (in meters) as: Xargus(m, cross-shore) = -[Eastings (m)-224800] and Yargus(m, alongshore) = -[Northings (m)-113600]. Click the image for a larger version.

For comparison, Figure 5 is a plan-view taken on year earlier.

Figure 5. Plan-view image on 26 September 2004 at 2300 GMT (1500 PST). Click the image for a larger version.

An archive of quality-controlled (QC’d) panorama and plan-view images is available on-line. Click here to access these files.

There are many data products that can be derived from Argus data. Below is an example of one such product. For a more complete presentation of data products, please click on the link, "Data Products, News, and Discussion" on the right-hand bar and search for "Data Reports" or click here.

Figure 6. Benson Beach 2.0m NAVD88 shoreline shape for February 2004 through September 2005 in local Argus coordinates (m, Figure 7 below). Also provided in each shape image is the dry-beach acreage calculated between the arbitrary bench mark at x=200 and the 2.0m shoreline. Click the image for a larger version.

Figure 7. Reference map for converting local Argus coordinates (m) to WA South State Plane coordinates (m, NAD83). Also shown on this map are reference lines and notations used in the analysis of shorelines, dry-beach acreage, and intertidal volumes. Click the image for a larger version.

Figure 8. Intertidal sand volume changes from February 2004 through September 2005 (upper panel) along with dry-beach acreage changes (middle panel) and the offshore wave statistics (lower panel, measured by the NDBC 46029 buoy). Sand volumes are between 0.69 and 2.26m NAVD88 and y = 800 and 3050m; acreages are between 2.0m NAVD88 contour and an arbitrary onshore baseline (Figure 7). Shown are the change (delta) and cumulative change (Cum) for the North (N), Middle (M), and South (S) sections of the beach (Figure 7). Click the image for a larger version.

For more information about:

The Columbia Regional Sediment Management (RSM) project, contact Hans R. (Rod) Moritz or Doris J. McKillip of the Portland District, US Army Corps of Engineers