|Camera installation for beach monitoring.
The USGS National Assessment of Coastal Change Hazards project is using video remote sensing to collect observations that will improve our understanding of coastal change. Video observations of the coast can be used to monitor a range of coastal processes, for example changes in the shoreline position, both seasonally and due to long-term effects such as sea-level rise, and instances of beach and dune erosion during extreme storm events. These observations are used to evaluate and develop computer models for predicting water levels at the shoreline driven by surge and waves, which are used by the USGS to identify the vulnerability of our coasts to flooding and erosion during storm events.
How does it work?
Remote video cameras are a powerful tool to continuously monitor long stretches of coast. The system is non-intrusive, runs automatically, requires little maintenance, and consists of:
- a video camera housed in a weather-proof case mounted atop a tall beachfront structure with an unobstructed seaward view, and
- a mini-computer wired to the camera and stored in a sheltered location with power and internet access.
At regular intervals, during daylight hours, the camera collects snapshots and videos. Each square element in an image, called a pixel, contains color intensity information, which can be used to extract information about the changing coastline.
How is it used?
The use of video cameras to monitor ever-changing coastal conditions eliminates the need to deploy individual instruments, which can be time consuming and do not provide observations at all times and at all locations. Images and videos taken from cameras are useful for observing current coastal conditions and for comparing how conditions along the coast change through time. This includes, for example, tracking increasing water levels during a storm and monitoring the potential impacts of waves colliding with protective sand dunes.
Snapshots, like these taken (a) before and (b) during a winter storm at the U.S. Army Corps of Engineers Field Research Facility in the Outer Banks, North Carolina, show changing beach conditions throughout the day. During this storm, high waves and surge created shoreline water levels that reached the steps of a beach access, indicated by the arrow.
A video, or sequence of individual images, can also be processed to create various image products, which can be used to actually measure a range of coastal processes, including:
- wave runup
- regular and extreme water level statistics
- shoreline position
- sandbar existence and movement
- rip current presence
- coastal change
For example, time-averaged images, which represent the time-mean of all the images collected during a video, are used to identify areas where waves are breaking, which show up as bright white bands in the image. From this image product, coastal features and hazards such as the shoreline position as it moves up and down the beach with the tide, the presence and shape of offshore sandbars, and the occurrence of rip currents can be extracted. Changes in all of these features through time provide valuable insight into the dynamic nature of coastal environments.
Bright white areas in time-averaged images show the presence of wave breaking. These images from the U.S. Army Corps of Engineers Field Research Facility in the Outer Banks, North Carolina, reveal the presence of (a) rip currents and (b) beach cusps, and expose (c) straight and (d) complex offshore sandbars.
Holman, R.A., Stanley, J., 2007, The history and technical capabilities of Argus: Coast. Eng., 54, 477-491.
The Coastal Imaging Lab at Oregon State University: a pioneer in developing optical remote sensing techniques for studying coastal processes, and operates several coastal video monitoring stations worldwide.
The U.S. Army Corps of Engineers Field Research Facility in Duck, North Carolina: a coastal video monitoring station that has been in operation since 1993.
Recent Images from Madeira Beach, Florida
A high resolution digital video camera is installed atop a waterfront hotel at Madeira Beach, Florida, overlooking the Gulf of Mexico coast.
Today’s most recent snapshot and time-averaged images are shown below. These images are used to examine a range of coastal processes including shoreline position, the presence of an offshore sandbar, and the extent of wave runup on the beach.
Camera hosted by Shoreline Island Resort.
Snapshot for 6 PM 11/22/2017
Time average image for 6 PM 11/22/2017
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.
Recent Images from Santa Cruz, California
Researchers at the USGS Pacific Coastal and Marine Science Center have also installed two- high-resolution video cameras atop the Dream Inn Hotel in Santa Cruz, Califonia, overlooking the coast in northern Monterey Bay.
The images collected will be used to study coastal processes on a west coast beach. See the most recent snapshot and time-averaged images here: https://walrus.wr.usgs.gov/sc/