Geoscience Reference
In-Depth Information
Table 1 Data for water balance calculations in 1966
Month
Surface
inflow
(m
3
/s)
Groundwater
inflow (m
3
/s)
Precipitation
(mm/day)
Natural
evaporation
(mm/day)
Irrigation
(m
3
/s)
Additional
evaporation
(mm/day)
I
2.30
0.43
0.77
0.39
5.59
II
2.00
0.58
0.81
0.39
5.59
III
2.28
0.62
1.39
1.22
5.59
IV
1.81
0.79
1.13
1.45
6.02
V
1.49
0.61
1.52
2.28
2.58
6.64
VI
1.32
0.72
0.63
3.73
1.34
7.13
VII
1.39
0.58
2.32
3.80
1.46
7.31
VIII
1.59
0.64
1.94
3.84
0.75
7.17
IX
1.50
0.58
0.80
2.39
0.44
7.01
X
1.42
0.53
1.42
1.78
6.51
XI
1.65
0.53
0.73
0.67
5.84
XII
2.08
0.47
1.29
0.33
5.59
process was carried out by means of the mathematical model (Majewski et al.
1988b
). The following requirements had to be fulfilled:
l
Maximum water level in the lake cannot exceed the elevation of 2.70 m asl.
l
Minimum water level in the lake cannot be lower than 0.70 m asl.
l
Minimum biological outflow from the lake is 0.40 m
3
/s.
l
Water for irrigation during vegetation period must be secured.
Calculations were carried out for one calendar year (1966) with a time step of
1 h. Averaged monthly values of the following model parameters were determined:
l
Surface and ground water inflow (m
3
/s)
l
Precipitation (mm/day)
l
Natural evaporation and additional evaporation (mm/day)
l
Irrigation requirements (m
3
/s)
These data are presented in Table
1
.
Results of calculations are presented in Fig.
4
. There is no problem during
months January-April. However, problems appear during months May-October
due to higher evaporation and water required for irrigation. To improve this situation,
the outflow from the lake was decreased to the minimum biological value of 0.4 m
3
/s.
However, it is shown (Fig.
4
) that the minimum water level (0.70 m asl) was
exceeded by about 0.10 m.
10 Possible Failure of the Upper Reservoir
The upper reservoir is constructed artificially on the nearby moraine hill. The total
water volume of the reservoir is 16 hm
3
. In case of breaching, the reservoir
embankment water which will flow out can endanger the nuclear power plant and
