Environmental Engineering Reference
In-Depth Information
Environmental Studies
An important advantage of satellite imagery is the recording of changing conditions with
time for a given area, such as deforestation, detection of degradation of vegetation from
pollution or other causes, and the extent of river-basin flooding.
Some applications for water bodies as shown by color variations include: varying water
depths in shallow water, different concentrations of sediment at mouths of rivers, and
thermal gradients indicative of pollution or saltwater intrusion.
Aerial Photographs
Stereoscopic examination of stereo-pairs of aerial photographs is an extremely useful
method in the determination of geologic conditions. For large areas it is preferable to obtain
photos at two scale ranges 1:60,000 to 1:40,000 (Figure 2.11) and 1:20,000 to 1:8,000 (
Figure
2.12)
,
with the smaller scales providing an overview and the larger scales providing details.
Slump slide scars
FIGURE 2.11
Stereo-pair of serial photos (scale 1:40,000) shows landform developing in metamorphic rocks from subtropical
weathering. Severe erosion and a number of landslides are apparent, including the rotational slides shown on
the larger scales as in
Figure 2.12
and
Figure 9.26.
