314
J. Fac-Beneda et al.
the case of the summer, elevated sea levels are related to the increase in precipitation
and increase (from the end of runoff of meltwater) inflow to river waters [28]. With
spring (April, May), the dominance of the eastern atmospheric circulation causing
coastal winds is associated with low average sea levels.
Climate change is accompanied by rising sea levels, and its different rate depends
on the location of coastal stations along the Polish coast of the open Baltic Sea [30].
Research indicates that the average annual sea level rise is lower in the western
part of the coast (0.07 cm year
–1 in ´
Swinouj´ scie) and increases towards the east
(0.17 cm year
–1 in Ustka up to 0.23 cm year
–1 in Władysławowo). On a seasonal
basis, the highest increase occurs in winter and spring (especially in February and
March), while in autumn and winter months (September, October, and December)
there are no upward trends.
The coastal lakes (Resko Przymorskie, Jamno, Bukowo, Kopa´ n, Gardno, Łebsko,
Sarbsko), often connected with the sea by engineered sections of rivers (canals),
play a unique role in the potamic outflow of the Pomeranian rivers. In practice, this
means that the lakes form an extension of the main drainage base on the mainland,
constituting a regional base. It is determined by the convergent rhythm of variations
in the level of lakes with sea fluctuations, the strongest correlating in the case of
Lake Łebsko (Fig. 16.6). At the same time, due to the location of lakes in the lower
sections of rivers, they play the role of receivers of water flowing down from entire
river basins, but also – which is not very beneficial – pollution.
Additional pressure on these hydrographic objects is exerted by the polder systems
with enforced water circulation.
Connection of the rivers with the sea both direct and through lakes has its hydrological and hydrochemical repercussions. The observed, long-term changes in the
main drainage base cause an increase in the level of coastal lakes. As a result, they may
also influence the decrease of potamic and groundwater outflow towards the sea, and
increase the entry of sea waters into the land. Such scenarios are shown by previous
research [21]. During short storm surges, sea waters block the free river runoff or
invade their course and the lakes located in the coastal zone. So far, the maximum
range of intrusions has been noted on the Łeba River for the profile in Cecenów
(20 km from the estuary). In storm situations, there may be a direct flood hazard,
R² = 0.8788
460
470
480
490
500
510
520
530
540
550
560
480
490
500
510
520
530
540
550
560
570
580
590
]
m
c
[
a
k
t
s
U
n
i
l
e
v
e
l
a
e
S
Lake level - Gardno [cm]
R² = 0.932
460
470
480
490
500
510
520
530
540
550
560
470 480 490 500 510 520 530 540 550 560 570 580 590
]
m
c
[
a
b
e
Ł
n
i
l
e
v
e
l
a
e
S
Lake level - Łebsko [cm]
(a)
(b)
Fig. 16.6 Dependence of water fluctuations of Gardno and Łebsko lakes from the level of the Baltic
Sea [31]
J. Fac-Beneda et al.
the case of the summer, elevated sea levels are related to the increase in precipitation
and increase (from the end of runoff of meltwater) inflow to river waters [28]. With
spring (April, May), the dominance of the eastern atmospheric circulation causing
coastal winds is associated with low average sea levels.
Climate change is accompanied by rising sea levels, and its different rate depends
on the location of coastal stations along the Polish coast of the open Baltic Sea [30].
Research indicates that the average annual sea level rise is lower in the western
part of the coast (0.07 cm year
–1 in ´
Swinouj´ scie) and increases towards the east
(0.17 cm year
–1 in Ustka up to 0.23 cm year
–1 in Władysławowo). On a seasonal
basis, the highest increase occurs in winter and spring (especially in February and
March), while in autumn and winter months (September, October, and December)
there are no upward trends.
The coastal lakes (Resko Przymorskie, Jamno, Bukowo, Kopa´ n, Gardno, Łebsko,
Sarbsko), often connected with the sea by engineered sections of rivers (canals),
play a unique role in the potamic outflow of the Pomeranian rivers. In practice, this
means that the lakes form an extension of the main drainage base on the mainland,
constituting a regional base. It is determined by the convergent rhythm of variations
in the level of lakes with sea fluctuations, the strongest correlating in the case of
Lake Łebsko (Fig. 16.6). At the same time, due to the location of lakes in the lower
sections of rivers, they play the role of receivers of water flowing down from entire
river basins, but also – which is not very beneficial – pollution.
Additional pressure on these hydrographic objects is exerted by the polder systems
with enforced water circulation.
Connection of the rivers with the sea both direct and through lakes has its hydrological and hydrochemical repercussions. The observed, long-term changes in the
main drainage base cause an increase in the level of coastal lakes. As a result, they may
also influence the decrease of potamic and groundwater outflow towards the sea, and
increase the entry of sea waters into the land. Such scenarios are shown by previous
research [21]. During short storm surges, sea waters block the free river runoff or
invade their course and the lakes located in the coastal zone. So far, the maximum
range of intrusions has been noted on the Łeba River for the profile in Cecenów
(20 km from the estuary). In storm situations, there may be a direct flood hazard,
R² = 0.8788
460
470
480
490
500
510
520
530
540
550
560
480
490
500
510
520
530
540
550
560
570
580
590
]
m
c
[
a
k
t
s
U
n
i
l
e
v
e
l
a
e
S
Lake level - Gardno [cm]
R² = 0.932
460
470
480
490
500
510
520
530
540
550
560
470 480 490 500 510 520 530 540 550 560 570 580 590
]
m
c
[
a
b
e
Ł
n
i
l
e
v
e
l
a
e
S
Lake level - Łebsko [cm]
(a)
(b)
Fig. 16.6 Dependence of water fluctuations of Gardno and Łebsko lakes from the level of the Baltic
Sea [31]