open file - Viru Peipsi

Table1. Changes in annual runoff according to different climate change
scenarios (percentages)
River Station HADMID HADMIN HADMAX HAMMID HAMMIN HAMMAX
Ahja Ahja 26 13 31 39 21 51
Ahja Koorvere 36 24 40 48 32 59
Avijo Mulgi 24 11 30 41 21 54
Emajõgi Tartu 46 33 51 60 42 72
Kääpa Kääpa 30 16 36 48 27 61
Kunda Sämi 15 5 19 27 13 36
Piiga009 Piigaste 18 7 22 31 15 41
Põltsamaa Pajusi 23 11 28 37 19 46
Pungerja Roostoja 22 10 28 38 20 49
Purtse Lüganuse 18 6 23 33 15 43
Tagajõgi Tudulinna 22 9 28 40 20 52
Võhandu Räpina 26 14 31 40 22 51
Võhandu Himmiste 29 16 33 42 24 54
Not only total increase of annual runoff is important but also its seasonal
distribution. In most of the impact studies, the consequences of a greenhouse
effect for runoff are analysed and discussed, while seasonal patterns of runoff
have received less attention, especially concerning their regularity. Modelling
results demonstrate a possibility of enormous changes in seasonal runoff on
the eastern part of Estonia. The results below (Figures 1–3) illustrate
geographical differences in the sensitivity of runoff to climate change.
Maximum runoff is more sensitive than minimum runoff.
For the studied rivers, the modelled annual curve of runoff is similar to
baseline. A decrease of modelled runoff in spring and its increase in autumn
is typical to all river basins, especially to the rivers of North-Estonia.
Figures 1–3 demonstrate a variety of runoff responses to climate change in
different landscape regions. Observed curves of monthly runoff for the
baseline period (1961–1990) and modelled curves for the year 2100 are
presented. In addition to the medium climate change scenarios HADMID and
HAMMID, HADMIN as the lowest change scenario and HAMMAX as the
highest one are demonstrated.
Võhandu River basin is located in South-East Estonia in the region of the
most continental climate. There, changes in annual course of runoff will be the
less remarkable (Fig. 1). The runoff maximum in spring will move by a month
earlier, but will not decrease. ECHAM3TR model indicates even an increase
of the maximum.