1. TOLERATE Hydrological scenarios – results from Pori Noora Veijalainen Suomen Ympäristökeskus TOLERATE researchers meeting 23.8.2007, VATT

2. Method  Climate change scenarios From Ilmatieteen laitos Climate change effects by 2020-2049 (from 1971-2000) 12 scenarios (3 emission scenarios, 1 average of many models, 3 climate models) Average model scenario with average emission scenario is called KA A1B and used for further studies  Simulation of 30 years of discharges for Pori with WSFS  Gumbel distribution fitted to the yearly maximums  1/20, 1/100 and 1/250 year floods of 2020-49 are compared to baseline period  Form of the 1/250 flood is calculated from average of the three largest simulated floods in the 30 year periods

3. Regulation  For baseline period the regulation schedules are based on average observed water levels and discharges  Three alternative regulation schedules for 2020-40 Same as baseline Does not work well Unrealistic since in reality the schedules are flexible Slightly altered Less winter drawdown Current water level boundaries still in effect as much as possible Severely altered No winter drawdown if discharges are large

4. Results Change % Gumbel Sligtly altered regulation Severely altered regulation Return periodMinMax KA A1BMinMax KA A1B 2504.2 %15.0 %9.0 %2.0 %14.3 %6.0 % 1003.4 %13.8 %8.3 %0.9 %12.9 %5.3 % 201.5 %11.3 %6.7 %-1.4 %9.0 %3.6%