10 Hydrological Impacts of Climate Changes in Romania
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to [64], hydrological projections of peak flows illustrate changes in many areas of
Europe, both positive and negative, with a general decrease in flood magnitude and
earlier spring floods for catchments with snowmelt-dominated peak flows. Similar
results were found by Rojas et al. [81], showing that in eastern Germany, Poland,
southern Sweden and, to a lesser extent, the Baltic countries, the signal is dominated
by the significant reduction in snowmelt induced floods and decrease in 100-year
discharge. In other areas, as in western Europe and northern Italy, a strong increase
in future flood hazard was projected, mainly due to a pronounced increase in extreme
rainfall [81]. The flood magnitudes are expected to increase significantly south of
60 N latitude (mainly in large parts of Romania, Ukraine, Germany, France and
north of Spain) and to decrease in most of Finland, northwestern Russia and north of
Sweden [84]. In a recent study [88], the climate impact simulations show significant
decreasing in high flows for the Mediterranean region, from −11% at 1.5 °C up to
−30% at 3 °C global warming, mainly due to reduced precipitation. Small changes
(<±10%) are expected for river basins in Central Europe and the British Isles, under
different levels of warming. In northern regions, high flows are projected to increase
due to rising precipitation, but floods are projected to decrease due to less accumulated
snow and thus less snowmelt [88].
The impact of climate change on the low flow and hydrological drought characteristics is projected to be severe and large areas are expected to be affected by water
scarcity in the Mediterranean region, Middle East, southeast U.S., Chile, southwest
Australia and large parts of Asia [70, 74]. According to [71], the river basins in arid
regions will become even drier, while in the cold regions, a shift of the snow melt
peak and an increase of low discharges were identified. For most rivers in humid and
temperate climates, the results of the projections are considered uncertain.
In Europe, throughout the 21st century, the models indicate that streamflow
droughts will become more severe and persistent in many parts of the continent,
except for northern and northeastern regions where the drought hazard will decrease.
The most affected by the low flows reduction will be the southern regions [83]. The
projections showed that the hydrological drought magnitude and duration might
increase in Spain, France, Italy, Greece, the Balkans, south of the UK and Ireland
[84]. The low flows are expected to increase in the alpine and northern regions [87].
10.3 Overview of Changes in Main Climate Parameters
Controlling the River Flow in Romania
Located in the central part of Europe, Romania (area of 238,391 km
2 ) overlaps almost
entirely (97% of its territory) the Danube River Basin, occupying approximately
one-third of it [98]. The rest of 3% of the national territory is drained by small
rivers flowing into lakes located on the Black Sea coast. In the south and south-east
of Romania flows the Lower Danube River on a length of 1075 km (i.e., 38% of
its entire length of 2780 km) before reaching the Black Sea through the Danube
313
to [64], hydrological projections of peak flows illustrate changes in many areas of
Europe, both positive and negative, with a general decrease in flood magnitude and
earlier spring floods for catchments with snowmelt-dominated peak flows. Similar
results were found by Rojas et al. [81], showing that in eastern Germany, Poland,
southern Sweden and, to a lesser extent, the Baltic countries, the signal is dominated
by the significant reduction in snowmelt induced floods and decrease in 100-year
discharge. In other areas, as in western Europe and northern Italy, a strong increase
in future flood hazard was projected, mainly due to a pronounced increase in extreme
rainfall [81]. The flood magnitudes are expected to increase significantly south of
60 N latitude (mainly in large parts of Romania, Ukraine, Germany, France and
north of Spain) and to decrease in most of Finland, northwestern Russia and north of
Sweden [84]. In a recent study [88], the climate impact simulations show significant
decreasing in high flows for the Mediterranean region, from −11% at 1.5 °C up to
−30% at 3 °C global warming, mainly due to reduced precipitation. Small changes
(<±10%) are expected for river basins in Central Europe and the British Isles, under
different levels of warming. In northern regions, high flows are projected to increase
due to rising precipitation, but floods are projected to decrease due to less accumulated
snow and thus less snowmelt [88].
The impact of climate change on the low flow and hydrological drought characteristics is projected to be severe and large areas are expected to be affected by water
scarcity in the Mediterranean region, Middle East, southeast U.S., Chile, southwest
Australia and large parts of Asia [70, 74]. According to [71], the river basins in arid
regions will become even drier, while in the cold regions, a shift of the snow melt
peak and an increase of low discharges were identified. For most rivers in humid and
temperate climates, the results of the projections are considered uncertain.
In Europe, throughout the 21st century, the models indicate that streamflow
droughts will become more severe and persistent in many parts of the continent,
except for northern and northeastern regions where the drought hazard will decrease.
The most affected by the low flows reduction will be the southern regions [83]. The
projections showed that the hydrological drought magnitude and duration might
increase in Spain, France, Italy, Greece, the Balkans, south of the UK and Ireland
[84]. The low flows are expected to increase in the alpine and northern regions [87].
10.3 Overview of Changes in Main Climate Parameters
Controlling the River Flow in Romania
Located in the central part of Europe, Romania (area of 238,391 km
2 ) overlaps almost
entirely (97% of its territory) the Danube River Basin, occupying approximately
one-third of it [98]. The rest of 3% of the national territory is drained by small
rivers flowing into lakes located on the Black Sea coast. In the south and south-east
of Romania flows the Lower Danube River on a length of 1075 km (i.e., 38% of
its entire length of 2780 km) before reaching the Black Sea through the Danube