Abstract:
The entire land in the Southern Iran faces problems
arising out of various types of land
degradation, of which the vegetation type forms one
of the major ones. The Payab basin
(522,470 ha), which covers the lower reaches of Mon
d River, was chosen for a test risk
assessment of this type. The different kinds of dat
a for indicators of vegetation
degradation were taken from the records and publish
ed reports of Iran governmental
offices. A new model was developed for assessing th
e risk of vegetation degradation.
Taking into consideration nine indicators of vegeta
tion degradation, the model identifies
areas with ‘Potential Risk’ (risky zones) and areas
of ‘Actual Risk’ projecting the
probability of the worse degradation in future. The
preparation of risk maps, based on
the GIS analysis of these indicators will be helpfu
l for prioritizing the areas to initiate
remedial measures. A hazard map for each indicator
was first prepared in GIS by fixing
the thresholds of severity classes of the indicator
s. The risk classes were defined on the
basis of risk scores arrived at by assigning the ap
propriate attributes to the indicators and
the risk map prepared by overlaying some nine hazar
d maps in the GIS. Areas under
actual risk were found to be widespread (93%) in th
e basin and when the risk map
classified into subclasses of potential risk with d
ifferent probability levels the model
would project a statistical picture of the risk of
vegetation degradation.