John Day River, Oregon
REASON FOR PHOTOGRAMMETRY: To obtain a detailed topography and high-resolution photographs for habitat restoration. This provided large data sets in a short period of time.
PEOPLE INVOLVED: Kendra Russell, 303-445-3
PAPER ABSTRACT:
Low altitude balloon photogrammetry has been used to obtain high-resolution
photographs and detailed topographic information of large wood restoration
projects on the Middle Fork John Day River in Oregon. These data can be used to
monitor changes in channel morphology. Overlapping photographs and ground survey
control points are input into a photogrammetry software program to produce
orthophotographs and digital terrain model elevation points. To acquire the photos, a
remote controlled digital camera is attached to a 2.4 meter diameter helium balloon.
The balloon is tethered to the ground and flown above the location of interest. Ground
survey control is established by using global positioning system (GPS) equipment to
survey ground targets placed within the photographed area.
Photographs of the large wood structures were obtained in November 2008 and
September 2009. The photographs were used quantitatively to determine the exact
location of each log within the structure, log lengths, structure extent into channel, and
area of bars formed downstream of structures. Qualitatively the photographs were
used to see how much hydraulic cover for aquatic species was being provided, find the
formation of pools and bars that created habitat, and planform locations. Elevation
data were accurate on exposed land and but not in vegetated areas. Below water
topography is not accurately captured in the processed elevations. There are
limitations to a balloon-based data collection process. Data collection is very weather
dependent. Photo processing can be time intensive. Site conditions also determine the
feasibility: power lines, trees, and steep embankments can cause difficulties
maneuvering the equipment.
