10 Hydrological Impacts of Climate Changes in Romania
329
10.5 Hydrological Responses to Climate Changes: The
Example of the Valea Cerbului River Catchment
This part is focalized on a case study in which the hydrological responses to climate
changes were investigated in Valea Cerbului River catchment, based on recorded
data and hydrological simulations.
10.5.1 Study Area, Data and Methods
Valea Cerbului River catchment is located in the eastern extremity of the Southern
Carpathians, namely in the Bucegi Mountains, a nationally renowned region for
tourism related activities (Fig. 10.1). The main stream has almost 10 km length with
a mean slope of about 130 m/km. It has its source in the alpine region at 2125 m amsl
and the outlet at 870 m amsl. The catchment extends over an area of only 26 km
2
and has a mean altitude of 1500 m amsl (the maximum altitude is 2505 m amsl in
Vf. Omu peak) (Fig. 10.9). Its upper part overlaps calcareous conglomerates and has
steep slopes (between 45° and 80°) favoring rapid runoff and flash floods occurrence
[142, 176]. The hydrographic network is dense, but mainly formed by temporary
torrential streams.
The altitude imposes important spatial variations of the climatic parameters.
Thereby, the mean multiannual air temperature decreases from 5 to 6 °C at lowest altitudes to −2.5 °C at Vârfu Omu w.s., located at 2505 m amsl, where the frost
lasts, in average, 260 days/year and the snow layer has a mean duration of 140–220
days/year, with a monthly average thickness of up to 70–80 cm in March–April
[99]. The snow usually lasts until June on the upper part of the northern valleys,
two months longer than in the lower basin [177]. The mean annual precipitation in
Valea Cerbului catchment varies between 900 and 1030 mm [99]. The wet period
is May–August (over 100 mm/month on average), when heavy, convective rains are
specific, while in autumn and winter the amounts of precipitation are low.
The mean multiannual discharge of the Valea Cerbului River (calculated for the
period 1961–2012, based on data recorded at Bus , teni g.s., which controls approx.
96% of the total area of the catchment), is of 0.502 m
3 /s, equivalent to a specific
discharge of 19.8 l/s/km
2 . The maximum flow recorded is of 62.3 m
3 /s (on June,
19th 2001) and the minimum discharge is of only 0.030 m
3 /s (December, 16th 1963).
The flow regime is characterized by high waters in summer (38% from the mean
multiannual volume), with the maximum percentages in June and July (13% and
respectively 15% of the mean multiannual water volume), due to heavy convective
rains specific for this season. An important water volume is flowing in spring (30%)
when the runoff is influenced by rainfall cumulated with snowmelt. Low flow is
specific for both winter and autumn (13% and respectively 19%) [177].
The Lower Valea Cerbului River basin overlaps the northern part of the Bus , teni
town, a nationally renowned resort for both, winter and summer related tourism
activities. The river is crossed by very important international/national terrestrial
329
10.5 Hydrological Responses to Climate Changes: The
Example of the Valea Cerbului River Catchment
This part is focalized on a case study in which the hydrological responses to climate
changes were investigated in Valea Cerbului River catchment, based on recorded
data and hydrological simulations.
10.5.1 Study Area, Data and Methods
Valea Cerbului River catchment is located in the eastern extremity of the Southern
Carpathians, namely in the Bucegi Mountains, a nationally renowned region for
tourism related activities (Fig. 10.1). The main stream has almost 10 km length with
a mean slope of about 130 m/km. It has its source in the alpine region at 2125 m amsl
and the outlet at 870 m amsl. The catchment extends over an area of only 26 km
2
and has a mean altitude of 1500 m amsl (the maximum altitude is 2505 m amsl in
Vf. Omu peak) (Fig. 10.9). Its upper part overlaps calcareous conglomerates and has
steep slopes (between 45° and 80°) favoring rapid runoff and flash floods occurrence
[142, 176]. The hydrographic network is dense, but mainly formed by temporary
torrential streams.
The altitude imposes important spatial variations of the climatic parameters.
Thereby, the mean multiannual air temperature decreases from 5 to 6 °C at lowest altitudes to −2.5 °C at Vârfu Omu w.s., located at 2505 m amsl, where the frost
lasts, in average, 260 days/year and the snow layer has a mean duration of 140–220
days/year, with a monthly average thickness of up to 70–80 cm in March–April
[99]. The snow usually lasts until June on the upper part of the northern valleys,
two months longer than in the lower basin [177]. The mean annual precipitation in
Valea Cerbului catchment varies between 900 and 1030 mm [99]. The wet period
is May–August (over 100 mm/month on average), when heavy, convective rains are
specific, while in autumn and winter the amounts of precipitation are low.
The mean multiannual discharge of the Valea Cerbului River (calculated for the
period 1961–2012, based on data recorded at Bus , teni g.s., which controls approx.
96% of the total area of the catchment), is of 0.502 m
3 /s, equivalent to a specific
discharge of 19.8 l/s/km
2 . The maximum flow recorded is of 62.3 m
3 /s (on June,
19th 2001) and the minimum discharge is of only 0.030 m
3 /s (December, 16th 1963).
The flow regime is characterized by high waters in summer (38% from the mean
multiannual volume), with the maximum percentages in June and July (13% and
respectively 15% of the mean multiannual water volume), due to heavy convective
rains specific for this season. An important water volume is flowing in spring (30%)
when the runoff is influenced by rainfall cumulated with snowmelt. Low flow is
specific for both winter and autumn (13% and respectively 19%) [177].
The Lower Valea Cerbului River basin overlaps the northern part of the Bus , teni
town, a nationally renowned resort for both, winter and summer related tourism
activities. The river is crossed by very important international/national terrestrial