Morphometric characteristics of Urmia Lake are among those features that have been reported variously by different authors [12,1,17].
In general, Urmia Lake has been shrinking for a long time, so its depth
has decreased significantly during recent years. Due to 10 years of
progressive dry climate in the area, the water level is 3 meters less
than it was 20 years ago [28],
a dramatic change. Little is known about historical lake-level
variations because direct measurements have been sparse. Urmia lake had
an increased level (2 m) in the winter 1968/1969 but the variations
reached to an amount of 1284 m in 1977, with annual fluctuations of
about 1 m (Fig. 1).
There is a few data to show present lake-level variations, but the lake
is recovering from a different water resources resulting from favorable
climatic condition in 2007. Therefore, Urmia lake level reached to an
amount of 1273 m and 25 cm, which was reported by West Azarbaijan
(Urmia) Environment Organization.
However, highs and lows estimated from the odd casting-line measurement, or historical account [29-31] suggest an uncanny parallel with historical levels in the Great Salt Lake (Fig. 1) [1].
The water level of Great Salt Lake went down from 1999 to about 2003
due to less precipitation and increased from 2005 to the present
because of a couple of higher precipitation years.
However, at present, the Great Salt Lake is not continuing its
upward climb. The graph showed that Great Salt Lake elevation declined
from 1992 to 1997 and then began an upward climb to 1999 (Fig. 2).
The measurement of the level changes in Urmia lake by satellite showed
an increase from 1992 to 1995 and decline from 1995 through 2003 (U.S.
Geological Survey). A concomitant increase salinity (220–300 g/l) was
observed during the years of declining elevation [32]. For the 2003–2004 period, favorable climatic changes lead to an increase in the elevation [32], but it has been declining since that time (U.S. Geological Survey). Aleshikh et al. [33]
mapped the coastline changes for Urmia Lake using an innovative TM
(Satellite imagery made up of 7 bands, with bands 1–5 and 7 being
visible and near IR, and band 6 being thermal IR. The visible and near
IR bands all have 30 m pixel size, with the thermal IR band having a
pixel size of 120 m) and ETM+imagery (Satellite imagery is made up of 8
bands, with bands 1–5 and 7 being visible and near IR, band 6 being
thermal IR, and band 8 being panchromatic. The visible and near IR
bands all have 30 m pixel size, the thermal IR band has a pixel size of
60 m, and the panchromatic band has a pixel size of 15 m) method in
1989, 1998 and 2001. They concluded that the lake's small variations
(0.2 m) from Jun-1989 to Aug-1998 are permanent, but that the great
decrease in water depth from 1998 to 2001 (3 m), was not related to
these permanent fluctuations, but to the lake's hydrologic budgets.
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