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ARGUS
BEACH
MONITORING
STATION
from NorthWest Research Associates, Inc. |  |
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 | Panoramic & plan-view images now available! |
An ARGUS Beach Monitoring Station (ABMS) was installed in February 2003 in Homer, Alaska on the north side of Kachemak Bay, in the southwestern region of Alaska's Kenai Peninsula. The application of the ABMS for monitoring the nearshore environment of Homer is part of a cooperative research agreement between NorthWest Research Associates (NWRA), The United States Geological Survey (USGS) Coastal and Marine Geology Program (CMGP), and the Kachemak Bay Research Reserve. The primary objectives of this study are to quantify the short- and long-term morphodynamics in the Kachemak Bay nearshore as a function of wave energy and sediment supply. Ultimately, we hope to develop a better understanding of the interplay between fluids, sediments, and habitat by integrating shoreline and morphology observations with processes, anthropogenic influences, and ecosystem health.
Figure 1. A view of the ABMS camera tower looking east. |
Figure 2. Aerial photo of the ABMS site (star) showing the eight camera views and the region (within the camera views and the 1000m circle) to be surveyed by the ABMS. The eight cameras are labeled C1 through C8. The power of the lens on each camera is also noted (e.g., camera 1 has a 16mm lens). Camera 7 is a higher-power lens that overlaps Camera 6 (marked with dashed lines). Camera 6 captures the beach closer to shore than Camera 7 and Camera 7 maps with better resolution further from shore. |
The Homer ABMS is located near the shoreline, northwest of Homer's airport. The location is ideal for monitoring sediment movement and shoreline changes around the small promentory that juts out between the Beluga Slough and the Homer spit (Figure 2).
The Homer ABMS is unique in the large number of video cameras. (A more typical number is four.) The cameras are mounted on the 10m-high wooden tower that sits on a bluff approximately 20m above mean-lower-low-water (MLLW, Figure 1). The tower was designed by NWRA and built by the City of Homer under the supervision of Carey Meyer. The cameras cover a view of approximately 225 degrees from the shoreline southeast looking towards the Homer spit, across the bay to the shoreline looking northwest towards the Beluga Slough.
The camera images are used to map bathymetry (sand wave locations), shoreline features, and shoreline and cliff locations. To be able to use the camera images for surveying the nearshore, the cameras and objects in the camera views are surveyed into a local coordinate system. Mr. Gary Nelson of Ability Surveys (asurveys@homernet.net) worked with the ABMS researchers to obtain these critical data.
The ABMS video cameras provide hourly snap images, time averages (timex), and variance images. The latest snap images from the eight cameras are shown below. Time stamps on the images are in Alaska Standard Time year round. (Click on an image to enlarge it.) To view the latest timex or variance images, or to visit the image archive, click on the appropriate link below.
Snapshot Images ( 11 Mar 2010 06:09 AKDT )
| Camera 1 16mm |
Camera 2 12mm |
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| Camera 3 7.5mm |
Camera 4 7.5mm |
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| Camera 5 7.5mm |
Camera 6 7.5mm |
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| Camera 7 16mm |
Camera 8 16mm |
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You will find some images will be washed out because of the contrast between the dark material on the beach and the glare off the water. This is not a concern for the ABMS analysis since the contrast between the ocean and the beach provides a strong demarcation of the shoreline for mapping.
Because ABMS cameras are surveyed into a coordinate system, the oblique views of the cameras can be mapped (rectified) into a birds-eye view using photogrammetry methods. In addition, the eight camera images can be accurately merged so that the end result is a map of the Homer nearshore that looks like an aerial or satellite image. Shown below are recent rectified and merged images from the eight Homer ABMS cameras. An archive of rectified and merged images is also available in the birds-eye-view archive.
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| Figure 3. Panoramic snapshot image acquired from cameras 1 through 8 at noon on 11 June 2005. A large sand bar with a tidal pool can be seen in the forefront of the image. Click the image for a larger version. |
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| Figure 4. Rectified plan-view image of Figure 3. Coordinates are in the local Argus coordinate system (meters). Click the image for a larger version. |
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| Figure 5. Panoramic snapshot image acquired from cameras 1 through 8 at noon on 9 June 2004. Most evident in the comparisons of the 2004 and 2005 images is the movement of the fine-grain sand bars (referred to fondly as sand slugs). Click the image for a larger version. |
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| Figure 6. Rectified plan-view image of Figure 5. Coordinates are in the local Argus coordinate system (meters). Click the image for a larger version. |
Complementary Coastal Data for this Site
| NOAA NDBC | Weather | Predicted tide | Location Map |
For more information about:
The USGS Homer ABMS study:
Dr. Peter Ruggiero,
Dr. Guy Gelfenbaum.
The Kachemak Bay Research Reserve:
Angie Doroff.
ABMS and ABMS studies around the globe, contact info@planetargus.com
