The Oder Estuary - IOW

120
Table 3.5. Accumulation of nitrogen and phosphorus in the sediment of the Szczecin Lagoon
calculated from the model results and data on sediment accumulation from literature.
Grosses
Haff
MODELl
Kleiness
Haff
MODEL
HUMBO
RG et al.
2000
LEIPE et
al. 1998
MEYER
&
LAMPE
1999
Annual
accumulation in
sediment
[tons]
Total amount
accumulated in the
sediment within the
given period of
time
[tons]
nitrogen phospho
N:P
[mol
]
Tim
e
perio
d
[year
s]
Notes
nitrogen phospho
rus
rus
7,900 1,200 159,000 24,200 14.6 20 MODEL results
1980-99
1,500 230 30,000 4,600 15 20 Modeling results
1980-99
2,560 716 64,000 17,900 7.9 25
Modeling results
1971-96 (whole
Lagoon area)
1,000 300 100,000 30,000 7.4 100 Surface layer of
the sediment
(whole Lagoon
area)
510 76 51,000 7,600 14.9 100 Surface layer of
the sediment
(whole Lagoon
area)
The model results for the Grosses Haff are higher as compared to the literature data. As a result of
model calibration higher accumulation rate of nutrients in sediment of the Grosses Haff then the
Kleines Haff were obtained. This four-fold difference can be explained when additional aspects of
Grosses Haff character are taken into consideration. Some of the material that is indicated by the
model as accumulated in the sediment of the Grosses Haff might, in fact, be retained in the
uppermost part of the Oder estuary (river branches and Dabie Lake a shown in Figure 1.1) which in
the model constitutes part of the Grosses Haff model box. Another aspect that should be taken into
account is dredging of the shipping channel conducted in the Grosses Haff.
3.4.2 Retention in the upper part of the Oder Estuary on the polders and in Dabie
Lake.
The suspended matter budget of the Grosses Haff calculated by NOWAK (1980) based on the
measurement campaign during period 1956-57 and in 1970 indicates that a large portion of the
suspended matter load measured at the monitoring cross-section near Krajnik Dolny (at
Widuchowa) was retained in the estuary before riverine waters entered Roztoka Odrzanska
(Figure 1.1). Only 32 % of the suspended load measured at Widuchowa was finally transported to
the Grosses Haff. The remaining portion was deposited in Dabie Lake and among the river
branches of the upper part of the estuary. As a comparison, it can be mention that, according to