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L. Zaharia et al.
runoff for the main tributaries of the Lower Danube Basin (e.g., the Olt River at
Cornet g.s.), while in the rest of the year, the scenario trends are partially unclear,
mainly for the winter months.
In the Olt River basin, one of the largest watersheds in Romania, draining the
Carpathians and the central part of the Romanian plain (Fig. 10.1), the potential
impact of climate changes on the maximum streamflow was investigated by hydrological simulations (using the CONSUL model) for two periods: 1951–2010 (as
reference period) and 2011–2050 [161]. The results indicated a slight increase in
the future (up to 5%) in the annual maximum discharges. Significant increases of
maximum monthly discharges are expected in winter, July and August, while during
the spring months, in June and autumn, the projections indicate a decrease of the
maximum streamflow. In the future period, it is likely that floods will become more
frequent in winter and summer compared to the reference period, and rarer in spring
and autumn (except October). The high discharges (with return periods of 1000, 100,
50, 20 and 10 years) tend to rise in the upper part of the Olt River basin and to slightly
decrease in the lower part [161].
Within the European project CLAVIER (conducted between 2006 and 2009),
in which several Romanian institutions were involved, there were estimated the
hydrological impacts of climate changes based on the output of regional climate
models for several watersheds/rivers in Romania. REMO5.7-ERA40 (1961–2000)
and REMO5.7–A1B (1951–2050), data produced by the Max Planck Institute for
Meteorology in Hamburg, were used as climate change scenario for the hydrological
models (VITUKI–NHFS and VIDRA). The projections were made for some Romanian rivers draining different geographical regions. Thus, Vis , eu (at Bistra g.s.) and
Iza (at Vadu Izei g.s.) are tributaries of the Upper Tisa, located in the far north of the
country. Mures , River (at Arad and Ludus , gauging stations) and its tributaries Aries ,
(at Turda g.s.) and Târnava (at Mihalt , g.s.), drain the central part of Romania. Arges ,
River (at Malu Spart and Budes , ti gauging stations) and its tributary Dâmbovit , a (at
Lungulet , u g.s.) are located in the south of the country (Fig. 10.1).
For rivers in the northern part of the country (Vis , eu and Iza), a slight increase
of the mean annual discharges (less than 3%) is expected for the period 2021–2050
relative to the reference period (1961–1990). A significant increase (30–40%) is
projected in the winter season. For the spring-autumn period, the hydrological simulations indicate a slight variation, more important in spring, when decreases of −4 to
−14% are estimated for mean discharges (Fig. 10.7). For the other analyzed rivers,
the hydrological simulations indicated a general decrease of the mean annual discharges up to almost −15% by 2050. This decreasing is caused by the pronounced
flow reduction during the spring–autumn period, by up to almost −25% in some
catchments (a lower decrease of the average flow is expected in summer). In winter,
significant increases are projected, which can reach 30% in the south of the country
(e.g., Dâmbovit , a River) (Fig. 10.7) [167]. Concerning floods, the simulations made
within CLAVIER project do not indicate obvious changes. However, more frequent
floods are expected in winter. Torrential flash floods could occur more frequently,
while the floods with long duration and large volume may become rarer. The low
flows are expected to last longer [167].
L. Zaharia et al.
runoff for the main tributaries of the Lower Danube Basin (e.g., the Olt River at
Cornet g.s.), while in the rest of the year, the scenario trends are partially unclear,
mainly for the winter months.
In the Olt River basin, one of the largest watersheds in Romania, draining the
Carpathians and the central part of the Romanian plain (Fig. 10.1), the potential
impact of climate changes on the maximum streamflow was investigated by hydrological simulations (using the CONSUL model) for two periods: 1951–2010 (as
reference period) and 2011–2050 [161]. The results indicated a slight increase in
the future (up to 5%) in the annual maximum discharges. Significant increases of
maximum monthly discharges are expected in winter, July and August, while during
the spring months, in June and autumn, the projections indicate a decrease of the
maximum streamflow. In the future period, it is likely that floods will become more
frequent in winter and summer compared to the reference period, and rarer in spring
and autumn (except October). The high discharges (with return periods of 1000, 100,
50, 20 and 10 years) tend to rise in the upper part of the Olt River basin and to slightly
decrease in the lower part [161].
Within the European project CLAVIER (conducted between 2006 and 2009),
in which several Romanian institutions were involved, there were estimated the
hydrological impacts of climate changes based on the output of regional climate
models for several watersheds/rivers in Romania. REMO5.7-ERA40 (1961–2000)
and REMO5.7–A1B (1951–2050), data produced by the Max Planck Institute for
Meteorology in Hamburg, were used as climate change scenario for the hydrological
models (VITUKI–NHFS and VIDRA). The projections were made for some Romanian rivers draining different geographical regions. Thus, Vis , eu (at Bistra g.s.) and
Iza (at Vadu Izei g.s.) are tributaries of the Upper Tisa, located in the far north of the
country. Mures , River (at Arad and Ludus , gauging stations) and its tributaries Aries ,
(at Turda g.s.) and Târnava (at Mihalt , g.s.), drain the central part of Romania. Arges ,
River (at Malu Spart and Budes , ti gauging stations) and its tributary Dâmbovit , a (at
Lungulet , u g.s.) are located in the south of the country (Fig. 10.1).
For rivers in the northern part of the country (Vis , eu and Iza), a slight increase
of the mean annual discharges (less than 3%) is expected for the period 2021–2050
relative to the reference period (1961–1990). A significant increase (30–40%) is
projected in the winter season. For the spring-autumn period, the hydrological simulations indicate a slight variation, more important in spring, when decreases of −4 to
−14% are estimated for mean discharges (Fig. 10.7). For the other analyzed rivers,
the hydrological simulations indicated a general decrease of the mean annual discharges up to almost −15% by 2050. This decreasing is caused by the pronounced
flow reduction during the spring–autumn period, by up to almost −25% in some
catchments (a lower decrease of the average flow is expected in summer). In winter,
significant increases are projected, which can reach 30% in the south of the country
(e.g., Dâmbovit , a River) (Fig. 10.7) [167]. Concerning floods, the simulations made
within CLAVIER project do not indicate obvious changes. However, more frequent
floods are expected in winter. Torrential flash floods could occur more frequently,
while the floods with long duration and large volume may become rarer. The low
flows are expected to last longer [167].