Biophysical Characterisation of Fluvial Corridors at Reach to Network Scales - Fluvial Remote Sensing for Science and Management - page 237

Bankline
registration
points

200 Meters

W c

Bend
centroid

A m

Straight

1/2W L

R c

Crossing

200 Meters

Meandering

200 Meters

Best-fit
circle

(a)

Island braided

200 Meters

Braided

0 50 100 200 M

N

0 - 5 years 5 - 25 years 25 - 75 years > 75 years

(b) (c)

Figure 11.1 Example of geometrical properties and of biophysical polygons which can be extracted from aerial photos for a large
scale geographical characterisation : a) Planimetric properties of a meander bend. Reproduced from Heo et al. (2009)
Characterization & prediction of meandering channel migration in the GIS environment: A case study of the Sabine River in the
USA. Environmental Monitoring and Assessment; 152(1):155, with permission from Springer-Verlag, b) Delineation of in-channel
habitats (pools, riffles, lentic/lotic channels, bar bench). Reprinted from Geomorphology; 78(1-2), Beechie, T.J. et al. Channel
pattern and river-floodplain dynamics in forested mountain river systems, p. 124. Copyright 2006, with permission from Elsevier,
c) Geomorphic pattern types and age classes of floodplain patches (Beechie et al., 2006).

to the time of the map relative to the entire historic
record (Figure 11.2a and b). The use of historical series of
photos for overlaying channel positions and determining
an erodible corridor and erosion sensitivity has then been
discussed by Piegay et al. (2005).
Floodplain features can be detected from aerial
photographs providing evidence of lateral shifting
(Beechie et al., 2006), and opening new issues in terms
of floodplain geomorphic classification (e.g. Nanson and
Croke, 1992). Floodplain boundaries can also be detected
when the analysis is augmented by a DEM (Belmont,
2011). Combined with topographic or bathymetric
data, planimetric information can be extended to 3D
mapping of in-channel features. Figure 11.2c shows a
linear relationship between the measured areas of gravel

bars from maps and aerial photos mostly obtained
at low flow and their estimated volume, illustrating
that planimetric information can be a good proxy for
estimating sediment accumulation (Church and Rice,
2009). Volume is calculated from a map of bed elevation
changes developed from overlays of bathymetric surveys
available for different dates. Sediment budgets are also
increasingly established to quantify fluvial changes
through estimation of volume exchanges of sediment
per unit of time, as exemplified by McLean and Church
(1999), Gaeuman et al. (2003), Rollet (2007), or Lauer
and Parker (2008) at the reach-scale. Lane et al. (2010)
also provided an analysis of changes in braided channel
planform based on a DEM extracted from digital

photogrammetry performed on archived images.