16 Water Management in the Pomeranian Rivers Estuary Zone …
311
Table 16.3 Mean flow, mean specific runoff and outflow index of Pomeranian rivers in 1951–2015
(data base hydrometric monitoring IMGW-PIB)
River
Gauge station Period observation Mean Avg. Q [m 3
s −1 ]
Mean Avg. q [dm 3
s −1 km 2 ]
H [mm]
Rega
Trzebiatów
1951–2015
20.20
7.64
241
Pars˛ eta
Bardy
1956–2015
27.39
9.49
299
Wieprza Stary Kraków 1951–2015
15.72
10.20
207
Grabowa Grabowo
1976–2015
6.46
14.14
446
Słupia
Charnowo
1967–2015
17.81
11.15
352
Łupawa Smołdzino
1951–2015
8.32
10.31
325
Łeba
Cecenowo
1956–2015
11.72
10.66
336
Reda
Wejherowo
1961–2015
4.32
10.54
332
outflow [25] creating the most stable form of underground supply from deep aquifers.
The advantage of the underground supply component results from the presence of
favourable infiltration conditions, numerous lakes, endorheic areas, wetlands, as well
as significant areas with high ground retention capabilities. These include subglacial
channels, ice-marginal valleys (the Grabowa Ice-marginal Valley, Łeba-Reda Icemarginal Valley, Kashubian Ice-marginal Valley) and lowlands (the Gardno-Łeba
Lowland, Karwia Lowland) filled with permanent wetlands. The discharge of the
Pomeranian rivers varies depending on the size of rivers, from 4.32 m
3 s
−1 in the
Reda to 27.39 m
3 s
−1 in the Pars˛ eta (Table 16.3).
The seasonal nature of the outflow is modified by the annual cycle of changes
in the volume and forms of supply (Fig. 16.3). Higher outflow rates occur in the
winter half-year, culminating in March, while the lowest in the summer months.
The minimum values of the coefficient are recorded in August (the Rega, Pars˛ eta,
Wieprz, Grabowa Łupawa), in June (the Łeba, Reda) or in both mentioned months
they balance (the Słupia). The rivers of the western part of Pomeranian, like the Rega
and Pars˛ eta, show much higher variability of the outflow than the rivers of the central
and eastern parts. The scale of volatility in the first case ranges from 70–150%, while
in the second from 80 to 120% [3]. The distribution of the outflow in the annual cycle
qualifies the examined rivers to the hydrological regime of the nival type [25] poorly
(the Wieprza, Grabowa, Słupia, Łupawa, Łeba, Reda) or medium-developed (the
Rega, Pars˛ eta).
The unit outflow and the runoff layer are measures of the water resources of the
examined rivers. All rivers have a unit outflow higher than the average for Poland
estimated at 5.6 dm
3 s
−1 km
2 . The highest unit outflow is recorded for the Grabowa
and Słupia catchments, respectively 14.14 and 11.15 dm
3 s
−1 km
2 (Table 16.3), while
the lowest in the Rega and Pars˛ eta basins (<10 dm
3 s
−1 km
2 ).
The remaining rivers have a unit outflow similar to the average outflow value
calculated from the entire analysed area of Pomeranian (10.52 dm
3 s
−1 km
2 ). In
the case of the runoff layer, the boundary of the water resources of the examined
rivers’ catchment is determined by the Grabowa River with the highest values of
311
Table 16.3 Mean flow, mean specific runoff and outflow index of Pomeranian rivers in 1951–2015
(data base hydrometric monitoring IMGW-PIB)
River
Gauge station Period observation Mean Avg. Q [m 3
s −1 ]
Mean Avg. q [dm 3
s −1 km 2 ]
H [mm]
Rega
Trzebiatów
1951–2015
20.20
7.64
241
Pars˛ eta
Bardy
1956–2015
27.39
9.49
299
Wieprza Stary Kraków 1951–2015
15.72
10.20
207
Grabowa Grabowo
1976–2015
6.46
14.14
446
Słupia
Charnowo
1967–2015
17.81
11.15
352
Łupawa Smołdzino
1951–2015
8.32
10.31
325
Łeba
Cecenowo
1956–2015
11.72
10.66
336
Reda
Wejherowo
1961–2015
4.32
10.54
332
outflow [25] creating the most stable form of underground supply from deep aquifers.
The advantage of the underground supply component results from the presence of
favourable infiltration conditions, numerous lakes, endorheic areas, wetlands, as well
as significant areas with high ground retention capabilities. These include subglacial
channels, ice-marginal valleys (the Grabowa Ice-marginal Valley, Łeba-Reda Icemarginal Valley, Kashubian Ice-marginal Valley) and lowlands (the Gardno-Łeba
Lowland, Karwia Lowland) filled with permanent wetlands. The discharge of the
Pomeranian rivers varies depending on the size of rivers, from 4.32 m
3 s
−1 in the
Reda to 27.39 m
3 s
−1 in the Pars˛ eta (Table 16.3).
The seasonal nature of the outflow is modified by the annual cycle of changes
in the volume and forms of supply (Fig. 16.3). Higher outflow rates occur in the
winter half-year, culminating in March, while the lowest in the summer months.
The minimum values of the coefficient are recorded in August (the Rega, Pars˛ eta,
Wieprz, Grabowa Łupawa), in June (the Łeba, Reda) or in both mentioned months
they balance (the Słupia). The rivers of the western part of Pomeranian, like the Rega
and Pars˛ eta, show much higher variability of the outflow than the rivers of the central
and eastern parts. The scale of volatility in the first case ranges from 70–150%, while
in the second from 80 to 120% [3]. The distribution of the outflow in the annual cycle
qualifies the examined rivers to the hydrological regime of the nival type [25] poorly
(the Wieprza, Grabowa, Słupia, Łupawa, Łeba, Reda) or medium-developed (the
Rega, Pars˛ eta).
The unit outflow and the runoff layer are measures of the water resources of the
examined rivers. All rivers have a unit outflow higher than the average for Poland
estimated at 5.6 dm
3 s
−1 km
2 . The highest unit outflow is recorded for the Grabowa
and Słupia catchments, respectively 14.14 and 11.15 dm
3 s
−1 km
2 (Table 16.3), while
the lowest in the Rega and Pars˛ eta basins (<10 dm
3 s
−1 km
2 ).
The remaining rivers have a unit outflow similar to the average outflow value
calculated from the entire analysed area of Pomeranian (10.52 dm
3 s
−1 km
2 ). In
the case of the runoff layer, the boundary of the water resources of the examined
rivers’ catchment is determined by the Grabowa River with the highest values of