below:
•
If some water discharges are between “Mean Ecosystem Flow” and “Low Ecosystem Flow” of
Hydrological Classification System because of water abstraction then any unauthorised
water use
should be prohibited and water use by sectors should be reduced to the level that allows to have
“GOOD” status during first 6 years of WFD implementation cycle. If this is because of natural
reasons(such as climatic change, drought and etc) then in addition also in this planning sycle
relevant measures (planting forest strips, measures to combat drought , climate change impact
mitgation and other water protecting measures) should be realized to provide needed quantity
of water in the rivers that corresponds to “GOOD” ecological status.
•
If some water discharges are below “Low Ecosystem Flow” of Hydrological Classification System
then in addition to above measures some others (establishing possible water reservoirs in order
to increase river water during dry run periods or using ground and other alternative water sources
and etc.,) also need to be implemented to have “MODERATE” status in first 6 years period and
“”GOOD” status in second 6 years period of WFD implementation cycle.
Results
methodology hydrological classification methodology can be used to establish
environmental flow
rates for different rivers depending the type of water uses on prioritised basis
References
1.
Verdiyev V.G. Water resources of Eastern Caucasus rivers in conditions of climate change. Baku-2002, 224
pages.
2.
Imanov F.A., Verdiyev R.H., Rajabov R.F., Nuriyev A.A. Environmental flow of the rivers and their
determination methods, geographical problems of regions of Azerbaijan, materials of republic scientific-
practical conference, Baku, 2016, pages 219-224.
3.
Imanov F.A., Verdiyev R.H., Rajabov R.F., Nuriyev A.A. Methodology for determining environmental flow
of the rivers. Works by Azerbaijan Geographical Society, Geography and Natural Resources, no.2 (4). Baku,
2016, pages 109-116
4.
Imanov F.A. The minimum flow of the rivers of the Caucasus. Baku, 2000, Naphta-press Publishing House,
page 298.
5.
Ecological flows in the implementation of the Water Framework Directive. European Commission
Guidance Document no. 31. 2015.
6.
Tharme R.E. A global perspective on environmental flow assessment emerging trends
in the development
and application of environmental flow methodologies for rivers // River research and applications-19-
2003- pp. 397-441.
7.
EU Water Framework Directive, (2000/60/EC), European Communities, 2000.
98
Seasonal Variation of Temperature in the Southern Coastal Waters of the Caspian Sea,
off Anzali, Gilan in Iran.
Hadjizadeh-Zaker, Nasser
1, 2
1
Faculty of Environment, University of Tehran, Tehran, Iran, nhzaker@ut.ac.ir
2
Iranian National Institute for Oceanography and Atmospheric Science, Iran
Keywords: Caspian Sea, Temperature, Seasonal variation
Introduction
The Caspian Sea, as the largest inland water body on the Earth, is a very important marine environment
for the world and in particular for the lateral countries around it. The marine ecosystem of the Caspian is
unique and has a large stock of sturgeon. These living fossils are of high biological, ecological, genetic
and commercial importance (Dumont, 1998).
There is no doubt that having a good knowledge about water temperature in the Caspian Sea and its
seasonal variation are among the basic requirements for environmental and any other marine related
studies in this water body.
This paper presents the results of seasonal scale CTD measurements of coastal water temperature in the
western part of the southern Caspian Sea adjacent to Iran. The data were
collected over the period of
autumn 2004 to spring 2005, but have not been published before.
Figure 1. Study area and the position of CTD sampling stations (square dots).
99
Materials and methods
Field investigations were carried out by CTD profiling across the southern continental shelf of the
Caspian Sea off Anzali, Gilan in Iran (Figure 1). In this area the continental shelf has a width of about 12
km. The depth from the coast increases gently to about 50 m near the shelf break, after that the depth
sharply increases to 500 m (Figure 1).
The southern coast of the Caspian Sea has a subtropical climate characterized by warm summers and
mild winters (Rodionov 1994; Kosarev and Yablonskaya 1994). The air temperature
is maximum in
August and minimum in January (Kaplin 1995; Kosarev and Yablonskaya 1994). The surface temperature
in the southern basin attains its annual minimum of about 7
o
C in February. During the summer, the
maximum surface temperature is greater than 27 °C in the south (Kaplin 1995; Tuzhilkin and Kosarev
2005). Currents over the southern continental shelf are dominated by low frequencies less than 0.33 cpd
with peak energy at 7-9 days periods ( Zaker et al, 2011)
CTD profiling was conducted during the period of October 2004 to April 2005 and covered 3 seasons of
autumn, winter and spring. The CTD data profiles were collected at 17 stations along one transect
perpendicular to the coast (Figure 1). The CTD data were collected in a free fall mode and covered the
top 200m of water column. The CTD probe was released into the water column with a speed of 1 m/s.
The instrument was adjusted to collect data with a time interval of one second.
Results
In autumn, vertical temperature structure showed a thin thermocline located between depths of 30 m
and 40 m. The temperature above and below the thermocline were 19
o
C and 11.5
o
C, respectively.
The temperature in the surface mixed layer ranged between 19
o
C and 21
o
C. Below thermocline
temperature reduced to 8.5
o
C, 7.5
o
C and 6.5
o
C at depths of 80 m, 120 m and 200 m, respectively.
In winter no thermocline was observed across the depth in the study area. In This season, the water
temperature ranged between 10.5
o
C at the surface and 7.2
o
C at the depth of 180m and was almost
uniform over the top 100m of water column.
In mid spring, the temperature data showed a thin thermocline located between depths of 10 m and
20m. The temperature above and below the thermocline were 16.5
o
C and 11
o
C, respectively. In the
surface mixed layer, temperature ranged between 16.5
o
C and 17
o
C. Below the thermocline the
temperature reduced to 10
o
C and 6.8
o
C at depths of 50 m and 200 m, respectively and
vertical
temperature gradient reduced with increase in depth.
Discussion
The CTD data collected during autumn, winter and spring in the coastal waters of the Caspian Sea off
Anzali, Gilan in Iran, showed a reduction in the thickness of seasonal thermocline in autumn,
disappearing of it in winter and re-formation of the thermocline in spring. This procedure was in
accordance with the temperature data collected by Zaker et al (2007) off Babolsar, Mazandaran in Iran.
Zaker et al (2007) data also showed the presence of a strong seasonal thermocline in mid-summer
between 20 m and 50 m depth with 15
o
C temperature difference across it.
The two data together
indicate that the vertical temperature structure of southern waters of the Caspian Sea adjacent to Iran
are characterized by formation of a seasonal thermocline in spring which becomes strong in summer
and disappears in winter.
100