10 Hydrological Impacts of Climate Changes in Romania
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1–2 days) in the number of days with discharges exceeding Q 5% is expected during
August–October.
The simulations show that the annual frequency of discharges below Q 95%, projected for the future period will be lower compared to the reference period, up to
18 days. Monthly, the same decreasing trend is expected in February, March, August
and November. January is the only month for which all the scenarios indicate a possible low increase, by 1–1.4 days (scenarios average). In May there are not discharges
below Q 95% for neither the reference and future scenarios periods (Fig. 10.15b).
The results of our simulations emphasize the fact that the alterations of the climatic
parameters, as projected by the IPCC emissions scenarios, would impact on the
hydrological regime by shifting water volumes from summer and autumn to winter
and early spring, and by reducing the frequency of very low flows. However, the
magnitude of both high and low flows could increase, amplifying the torrential flow
character of the Valea Cerbului River.
10.6 Conclusions and Recommendations
As the hydrological system is highly sensitive to climate, it is expected that the alteration of climate parameters will impact the water cycle, affecting water availability
and human uses, as well as the aquatic ecosystems. This chapter presented a review
on the main research findings on hydroclimatic changes (observed and projected) in
Romania, in the context of the researches at global and European scale, and provided
new results on hydrological responses to climate changes issued from investigations in a small mountainous catchment (Valea Cerbului River basin), located in
the Romanian Carpathians. The most important climate changes with hydrological
impacts detected in the last half-century (after 1960) are a general warming at annual
and seasonal scale (excepting autumn) and increase of the precipitation amount in
autumn and of the daily maximum rainfall (mainly in summer and autumn). Important changes also affected the snow-related indices (mean snow depth, number of
days with snow cover and with snowfall, continuous snow cover duration), which had
significant downward trends. According to the climate simulations under different
scenarios, it is likely expected that these trends will continue and intensify in the
future.
The changes in the climatic parameters could be held responsible for some alterations and trends in the river flow, detected or estimated in studies conducted at
national and regional/local scale. At national level, in Romania, a general decreasing trend in the mean annual streamflow was detected after 1960. Some changes in
monthly and seasonal runoff variability were also found: upward trends in winter
(related to the increase of the air temperature and the shift of the precipitation from
solid to liquid form), downward trends in summer runoff (induced by the general
warming and increase of evaporation), upward trends in autumn flow. For the future
(by 2050), the simulations under climate scenarios indicate a general decline of the
339
1–2 days) in the number of days with discharges exceeding Q 5% is expected during
August–October.
The simulations show that the annual frequency of discharges below Q 95%, projected for the future period will be lower compared to the reference period, up to
18 days. Monthly, the same decreasing trend is expected in February, March, August
and November. January is the only month for which all the scenarios indicate a possible low increase, by 1–1.4 days (scenarios average). In May there are not discharges
below Q 95% for neither the reference and future scenarios periods (Fig. 10.15b).
The results of our simulations emphasize the fact that the alterations of the climatic
parameters, as projected by the IPCC emissions scenarios, would impact on the
hydrological regime by shifting water volumes from summer and autumn to winter
and early spring, and by reducing the frequency of very low flows. However, the
magnitude of both high and low flows could increase, amplifying the torrential flow
character of the Valea Cerbului River.
10.6 Conclusions and Recommendations
As the hydrological system is highly sensitive to climate, it is expected that the alteration of climate parameters will impact the water cycle, affecting water availability
and human uses, as well as the aquatic ecosystems. This chapter presented a review
on the main research findings on hydroclimatic changes (observed and projected) in
Romania, in the context of the researches at global and European scale, and provided
new results on hydrological responses to climate changes issued from investigations in a small mountainous catchment (Valea Cerbului River basin), located in
the Romanian Carpathians. The most important climate changes with hydrological
impacts detected in the last half-century (after 1960) are a general warming at annual
and seasonal scale (excepting autumn) and increase of the precipitation amount in
autumn and of the daily maximum rainfall (mainly in summer and autumn). Important changes also affected the snow-related indices (mean snow depth, number of
days with snow cover and with snowfall, continuous snow cover duration), which had
significant downward trends. According to the climate simulations under different
scenarios, it is likely expected that these trends will continue and intensify in the
future.
The changes in the climatic parameters could be held responsible for some alterations and trends in the river flow, detected or estimated in studies conducted at
national and regional/local scale. At national level, in Romania, a general decreasing trend in the mean annual streamflow was detected after 1960. Some changes in
monthly and seasonal runoff variability were also found: upward trends in winter
(related to the increase of the air temperature and the shift of the precipitation from
solid to liquid form), downward trends in summer runoff (induced by the general
warming and increase of evaporation), upward trends in autumn flow. For the future
(by 2050), the simulations under climate scenarios indicate a general decline of the