One of the major issues of studying sediment waves has been the inability to measure elevation changes of bars and beds at the resolution necessary to track sediment wave propagation (Lisle 1997). The photogrammetry described here is a cost effective method that provides the resolution required to track subtle elevation changes in great detail. According to Matthews (2008), if the correct workflow is used, a resolution of 0.25mm and a spatial accuracy equivalent of 0.025mm can be achieved. Other methods have also recently shown great advancements in creating DEMs, including terrestrial LiDAR. However, terrestrial LiDAR is orders of magnitude more expensive than photogrammetry and cannot be used on a landscape covered by water. For example, Westoby et al. (2012) applied both the photogrammetry technique and terrestrial LiDAR to three study locations and found that photogrammetry paired with software similar to Agisoft Photoscan produces better resolution than terrestrial LiDAR. A preliminary test of the photogrammetric methods was completed in September 2015 on Jacoby Creek, at Brookside Bridge, Arcata, CA. A one square meter area on a section of submerged gravel bar was used as a test site. Twenty seven photographs were taken at different angles of the area and then analyzed in Agisoft Photoscan to produce a dense cloud. At the Jacoby Creek site, a one square meter area was used because the purpose of the test was to evaluate if photogrammetry is possible on a submerged bar. On the Klamath River, the study sites will be much larger (on the order of tens of meters) to capture expected sediment deposition along the full bar length and full channel width. Figure 1.
One of the major issues of studying sediment waves has been the inability to measure elevation changes of bars and beds at the resolution necessary to track sediment wave propagation (Lisle 1997). The photogrammetry described here is a cost effective method that provides the resolution required to track subtle elevation changes in great detail. According to Matthews (2008), if the correct workflow is used, a resolution of 0.25mm and a spatial accuracy equivalent of 0.025mm can be achieved. Other methods have also recently shown great advancements in creating DEMs, including terrestrial LiDAR. However, terrestrial LiDAR is orders of magnitude more expensive than photogrammetry and cannot be used on a landscape covered by water. For example, Westoby et al. (2012) applied both the photogrammetry technique and terrestrial LiDAR to three study locations and found that photogrammetry paired with software similar to Agisoft Photoscan produces better resolution than terrestrial LiDAR. A preliminary test of the photogrammetric methods was completed in September 2015 on Jacoby Creek, at Brookside Bridge, Arcata, CA. A one square meter area on a section of submerged gravel bar was used as a test site. Twenty seven photographs were taken at different angles of the area and then analyzed in Agisoft Photoscan to produce a dense cloud. At the Jacoby Creek site, a one square meter area was used because the purpose of the test was to evaluate if photogrammetry is possible on a submerged bar. On the Klamath River, the study sites will be much larger (on the order of tens of meters) to capture expected sediment deposition along the full bar length and full channel width. Figure 1.
Curran_NSF_MockProposal.docx