Manual - International Environmental Technology Centre

4.B. HOW TO ASSESS LANDSCAPE IMPACTS ON WATER QUALITY
A landscape is the framework for all biogeochemical
and ecological processes. Its structure defines
the rate of water and chemical exchanges between
land and water ecosystems in catchments and
species biodiversity. All these factors determine
the self-regulating potential of ecosystems and
their resilience to human impacts.
This chapter presents basic methods of landscape
assessment using aerial photography and remotely
sensed imagery in conjunction with GIS technology
for estimating the rate, direction, and possible
impact of landscape changes on natural resources,
such as water and biodiversity.
HOW ARE LANDSCAPES ASSESSED?
From the point of view of protection and management
of natural resources it is important to identify
and quantify the following landscape
structures (Table 4.4):
Fig. 4.2
The Lubrzanka River Catchment
in the Swietokrzyskie Mountains of Poland
(photo: Department of Applied Ecology)
One of the most efficient methods for identification
of these areas, and therefore estimation of
their role in water and nutrient circulation, is teledetection,
a method based on recording, visualization
and analysis of electromagnetic radiation.
Teledetection incorporates classic aerial photography,
based on visible light, and recording and
visualization of other parts of the electromagnetic
spectrum. The type of electromagnetic radiation
used for analysis of landscape structures influences
the type of information gained and, therefore,
one’s ability to interpret data - photointerpretation
(Table 4.5).
HOW ARE LANDSCAPE STRUCTURES IDENTIFIED
ON AERIAL PHOTOGRAPHS?
Aerial photography provides large amounts of information
about the area of interest including:
physical profile, freshwater distribution and its
quantity and quality, distribution and biomass of
vegetation and characteristics of human impacts.
There are, however, two points, that must be
emphasized:
to find and properly interpret the information,
direct observations in the landscape
have to be carried out; and
knowledge about an area has to be obtained
and a clear goal of the survey has to be
set prior to the analysis of photographs.
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Surveys & Assessments: Landscape