open file - Viru Peipsi

2.50
mm/day
2.00
1.50
1.00
0.50
Baseline
HADMID
HADMIN
HAMMID
HAMMAX
0.00
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
Fig. 3. Changes in monthly runoff in Kunda River (station Sämi).
Shift of spring runoff maximum earlier will result in longer duration of summer
low water period and in decrease of total runoff during vegetation period (from
April to September) in many river basins of Estonia. The area of increased
runoff in summer is located in South-East Estonia and of decreased values in
the rest of the territory. The most remarkable decrease is modelled for rivers
with relatively high spring maximum runoff and not higher natural regulation
(River Tagajõgi and River Pedja).
There are big differences in the ratio of minimum and maximum runoff
between the river basins, although the difference between modelled and
observed monthly minimum runoff has a low regional variation and was
positive. It indicates that change in minimum runoff is not projected in case of
climate warming, but the decrease of maximum runoff may be significant. The
ratio between maximum and minimum monthly runoff will decrease very
much. Therefore, seasonal fluctuations of runoff will remarkably diminish due
to climate change and natural regulation of runoff will be increased (Table 2).
Table 2. Changes of coefficient of annual runoff natural regulation
River–station Observe HADMID HADMIN HADMAX
d
Ahja–Ahja 0.87 0.90 0.89 0.90
Ahja–Koorvere 0.88 0.91 0.90 0.91
Avijōgi–Mulgi 0.75 0.79 0.78 0.79
Emajōgi–Tartu 0.90 0.91 0.91 0.91
Kunda–Sämi 0.85 0.89 0.88 0.88
Kääpa–Kääpa 0.78 0.83 0.81 0.82
Pedja–Tõrve 0.78 0.81 0.80 0.81
Piigaste–Piigaste 0.82 0.85 0.83 0.86
Pōltsamaa–Pajusi 0.85 0.88 0.88 0.87
Pungerja–Roostoja 0.75 0.80 0.78 0.80
Purtse–Lüganuse 0.77 0.81 0.79 0.81