446
D. C. Diaconu
Mare Island with a length of 9.5 km, a maximum width of 4 km and an area of
approx. 1950 ha is delimited by the Danube branches (185 to 175 km) and Cravia;
The Arapu Island has a length of 3.5 km, a maximum width of 1.5 km and an area
of approx. 250 ha, being between the Danube branches (km 180 to 176) and Arapu.
The embankment has maintained broadly the same situation of stream flow on
the channels, but it has modified the actual value of the stream flows so that the
percentages of the drains are almost the same as the ones before the embankment.
On average, the Macin Channel transports 11.70% of the stream flow from Vadu Oii,
the Navigable Danube 67.11% and the Valciu Waterway 21.19% of the stream flow
at Vadu Oii:
• The Macin Channel—transports 9.63% at the shallow waters from Vadu Oii (in
1990–8.47%) and 13.18% at the deep waters (in 1970–13.17%);
• The Navigable Danube Channel—transports at the deep waters 65.41% (May) the
stream flow at Vadu Oii (in 1970–64.81%) and 69.54% (in 1990–70.43%);
• The Valciu Channel—transports 20.79% at the shallow waters (in 1990–21.10%)
and 21.43% at the deep waters (in 1970–21.52%). In 1970 the stream flow at Vadu
Oii was 13,590 m
3 /s, and in 1990–2530 m
3 /s.
In order to achieve the objective undergone in the Small Island of Braila to identify
and manage the water resources in order to develop some bodies of water as reservoirs,
there have been two stages as follows. A terrain one during which there have been
identified the current geographical conditions of stream flow and of terrain usage and
an official one that had to do with the building up of a database and the integration
of all the hydro-meteorological information by using the ArcSwat application.
Hydrological parameters, presented as multiannual environments after 1994,
according to data taken from the Braila Hydrological Station, synthetically describe
the present state of the Danube waters in this sector. The turbidity of 0.051 g/l, the
average solid flow of 10.4 million tons, the variance amplitude the 4.5 m level and
the water drainage rate that records annually the following average water velocity
values: 0.6, 0.8 m
3 /s during average water and 1.1 m
3 /s during high water.
It is worth mentioning that the hydrological regime of the lower course of the
Danube is marked by the moment when the indigestion of some precincts was made
in order to obtain agricultural land within the Danube meadow, starting with 1904,
but we can significantly mention the year 1962 when the afforested area 106,233 ha
to reach the maximum of 430,000 ha in 1987. As a result of this, on many river
sections, the active section of the river was reduced, thus increasing the leakage
velocity at high levels, the entrainment of sedimentary alluviums and the recording
of higher maximum downstream flows than naturally up to now. But the second
important moment is the construction of the energy and navigation system from the
Iron Gates I (Portile de Fier I) (1964–1972) and the Iron Gates II (Portile de Fier
II) (1985–1986), which formed two huge reservoirs with a huge volume, in which
more than 80% of the transported river is deposited. If, for the period 1931–1970,
the average annual flow rate of alluvia transported on the Vadu Oii—Braila sector,
had values ranging from 1640 to 1680 kg/s, between 1971 and 1992 it decreases to
average values between 710 and 820 kg/s. in the period 1992–2003, it would be only
D. C. Diaconu
Mare Island with a length of 9.5 km, a maximum width of 4 km and an area of
approx. 1950 ha is delimited by the Danube branches (185 to 175 km) and Cravia;
The Arapu Island has a length of 3.5 km, a maximum width of 1.5 km and an area
of approx. 250 ha, being between the Danube branches (km 180 to 176) and Arapu.
The embankment has maintained broadly the same situation of stream flow on
the channels, but it has modified the actual value of the stream flows so that the
percentages of the drains are almost the same as the ones before the embankment.
On average, the Macin Channel transports 11.70% of the stream flow from Vadu Oii,
the Navigable Danube 67.11% and the Valciu Waterway 21.19% of the stream flow
at Vadu Oii:
• The Macin Channel—transports 9.63% at the shallow waters from Vadu Oii (in
1990–8.47%) and 13.18% at the deep waters (in 1970–13.17%);
• The Navigable Danube Channel—transports at the deep waters 65.41% (May) the
stream flow at Vadu Oii (in 1970–64.81%) and 69.54% (in 1990–70.43%);
• The Valciu Channel—transports 20.79% at the shallow waters (in 1990–21.10%)
and 21.43% at the deep waters (in 1970–21.52%). In 1970 the stream flow at Vadu
Oii was 13,590 m
3 /s, and in 1990–2530 m
3 /s.
In order to achieve the objective undergone in the Small Island of Braila to identify
and manage the water resources in order to develop some bodies of water as reservoirs,
there have been two stages as follows. A terrain one during which there have been
identified the current geographical conditions of stream flow and of terrain usage and
an official one that had to do with the building up of a database and the integration
of all the hydro-meteorological information by using the ArcSwat application.
Hydrological parameters, presented as multiannual environments after 1994,
according to data taken from the Braila Hydrological Station, synthetically describe
the present state of the Danube waters in this sector. The turbidity of 0.051 g/l, the
average solid flow of 10.4 million tons, the variance amplitude the 4.5 m level and
the water drainage rate that records annually the following average water velocity
values: 0.6, 0.8 m
3 /s during average water and 1.1 m
3 /s during high water.
It is worth mentioning that the hydrological regime of the lower course of the
Danube is marked by the moment when the indigestion of some precincts was made
in order to obtain agricultural land within the Danube meadow, starting with 1904,
but we can significantly mention the year 1962 when the afforested area 106,233 ha
to reach the maximum of 430,000 ha in 1987. As a result of this, on many river
sections, the active section of the river was reduced, thus increasing the leakage
velocity at high levels, the entrainment of sedimentary alluviums and the recording
of higher maximum downstream flows than naturally up to now. But the second
important moment is the construction of the energy and navigation system from the
Iron Gates I (Portile de Fier I) (1964–1972) and the Iron Gates II (Portile de Fier
II) (1985–1986), which formed two huge reservoirs with a huge volume, in which
more than 80% of the transported river is deposited. If, for the period 1931–1970,
the average annual flow rate of alluvia transported on the Vadu Oii—Braila sector,
had values ranging from 1640 to 1680 kg/s, between 1971 and 1992 it decreases to
average values between 710 and 820 kg/s. in the period 1992–2003, it would be only