10 Hydrological Impacts of Climate Changes in Romania
323
(situated in the southern part of the country), at Pites , ti S , trand g.s. (Fig. 10.1), when
compared to the reference period 1950–1992, the average annual discharge will
decrease by almost 22%. Significant decreases (over 40–50%) are expected in spring
(mainly in April and May) and autumn (September–October) while in the winter
months, the average discharges will be much higher (with up to 86% in January)
[152]. In the Târnava River basin (located in the central part of the country, in the
Transylvanian Plateau) at Mihalt , g.s. (Fig. 10.1), projections for 2075 with the same
climatic model (CCCM) showed a high increase in the average monthly flow in
winter (over 70% in January) and decreases of −20 to −30% in the spring months
(especially in March and April) and in September, relative to the reference period of
1961–2000 [153].
In the Buz˘ au and Ialomit , a watersheds (covering External Carpathian Curvature
region and the neighboring lowlands—hills and plains), the climate changes impacts
on streamflow were estimated in [154, 159], by using three GCMs for three future
time horizons (2025, 2050, and 2100), relative to the reference period 1971–2000 (the
researches were performed within the European project CECILIA). The hydrological
simulation (made with the water balance model WatBal) indicated notable changes
in mean annual and monthly streamflow. Thus, the mean annual discharges decrease
as the time horizon is larger and could reach 30%. During the winter and early
spring periods (from November/December to February/March), an increase in mean
monthly flow was detected on long-term, more pronounced for the rivers draining the
mountainous area. The simulations also showed the seasonal variability amplification
[159].
Also in the Ialomit , a River basin, it was investigated the potential impact of climate
change on maximum flow regime. The discharges for the future period 2011–2050
and the reference period 1951–2010 were simulated with the CONSUL hydrological model, by considering the A1B scenario [157]. The projections show an earlier
occurrence of the floods in spring in the future period relative to the reference period.
The monthly maximum discharges will be higher in winter and July, and lower in
April–June as well as in September–October. While in the reference period the highest number of annual flood peaks was recorded in October, in the future (2011–2050)
the most annual floods will occur in March and April [157].
In the Siret River basin (the largest catchment in Romania, draining the eastern
part of the country; Fig. 10.1) the climate change impact on maximum flow was
investigated based on simulations made for the period 2011–2050, relative to the
reference period 1951–2010 [156]. The projections show that in the future, most
annual flood peaks will appear earlier in the year, in March–July, compared to the
reference period, when they occur during April–August. In the same watershed,
according to [172] for the period 2031–2060 (by simulations based on ENSEMBLES
data under A1B SRES scenarios) a decline in average runoff from April–September
(up to −25%) and tendencies towards an increase in winter (January and February)
are expected. The cited reference indicates that during the period 2031–2060, the
majority of the climate scenarios applied so far show a clear reduction in summer
323
(situated in the southern part of the country), at Pites , ti S , trand g.s. (Fig. 10.1), when
compared to the reference period 1950–1992, the average annual discharge will
decrease by almost 22%. Significant decreases (over 40–50%) are expected in spring
(mainly in April and May) and autumn (September–October) while in the winter
months, the average discharges will be much higher (with up to 86% in January)
[152]. In the Târnava River basin (located in the central part of the country, in the
Transylvanian Plateau) at Mihalt , g.s. (Fig. 10.1), projections for 2075 with the same
climatic model (CCCM) showed a high increase in the average monthly flow in
winter (over 70% in January) and decreases of −20 to −30% in the spring months
(especially in March and April) and in September, relative to the reference period of
1961–2000 [153].
In the Buz˘ au and Ialomit , a watersheds (covering External Carpathian Curvature
region and the neighboring lowlands—hills and plains), the climate changes impacts
on streamflow were estimated in [154, 159], by using three GCMs for three future
time horizons (2025, 2050, and 2100), relative to the reference period 1971–2000 (the
researches were performed within the European project CECILIA). The hydrological
simulation (made with the water balance model WatBal) indicated notable changes
in mean annual and monthly streamflow. Thus, the mean annual discharges decrease
as the time horizon is larger and could reach 30%. During the winter and early
spring periods (from November/December to February/March), an increase in mean
monthly flow was detected on long-term, more pronounced for the rivers draining the
mountainous area. The simulations also showed the seasonal variability amplification
[159].
Also in the Ialomit , a River basin, it was investigated the potential impact of climate
change on maximum flow regime. The discharges for the future period 2011–2050
and the reference period 1951–2010 were simulated with the CONSUL hydrological model, by considering the A1B scenario [157]. The projections show an earlier
occurrence of the floods in spring in the future period relative to the reference period.
The monthly maximum discharges will be higher in winter and July, and lower in
April–June as well as in September–October. While in the reference period the highest number of annual flood peaks was recorded in October, in the future (2011–2050)
the most annual floods will occur in March and April [157].
In the Siret River basin (the largest catchment in Romania, draining the eastern
part of the country; Fig. 10.1) the climate change impact on maximum flow was
investigated based on simulations made for the period 2011–2050, relative to the
reference period 1951–2010 [156]. The projections show that in the future, most
annual flood peaks will appear earlier in the year, in March–July, compared to the
reference period, when they occur during April–August. In the same watershed,
according to [172] for the period 2031–2060 (by simulations based on ENSEMBLES
data under A1B SRES scenarios) a decline in average runoff from April–September
(up to −25%) and tendencies towards an increase in winter (January and February)
are expected. The cited reference indicates that during the period 2031–2060, the
majority of the climate scenarios applied so far show a clear reduction in summer