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6. CONCLUSIONS To assure high dam safety during its reconstruction is essential. In the paper the general guidance is presented to specify the probability of the check flood for dam safety assessment during the remedial works. However, construction activities may, during certain period, call for temporarily both structural and non- structural arrangements which keep dam safety at the prescribed level. These measures concern the attenuation of arriving flood and thus lowering maximum water level during the specified check flood. Here an examples are reservoir water drawdown and/or lowering spillway crest during critical construction phases. Another possibility is to increase threshold water level by cofferdams or also operatively by sandbags. Final safety assessment must prove that the threshold water level is higher than the maximum water level at any construction phase. 7. ACKNOWLEDGEMENTS This research was supported by the TACR TH03030182 project “Protection of hydraulic structures against action caused by oscillatory wind waves” and FAST- S-17-4066 “The assessment of the filtration instability origin in the soils by the limit state method”. REFERENCES [1] BOWLES D.S., ABOELATA M., 2007, Evacuation and life-loss estimation model for natural and dam break floods, In Extreme hydrological events: new concepts for security, O.F. VASILIEV et al. (ed.), NATO Science Series, 78, Springer, Dordrecht, 363-383, DOI: 10.1007/978-1-4020-5741-0_25. [2] BROWN C.A., GRAHAM W.J., 1988, Assessing The Threat To Life From Dam Failure, Journal Of American Water Resources Association, 24 (6), 1303-1309, DOI: 10.1111/j.1752-1688.1988.tb03051.x. [3] CSN 75 2935, 2014, Safety assessment of water structures during floods, Czech standard, (in Czech). [4] DAM SAFETY, 2011, Dam safety public protection guidelines. A risk framework to support dam safety decision-making. U.S. Department of the Interior Bureau of Reclamation, Dam Safety Office, Denver, Colorado, USA, 32 p., available online at https://www.usbr.gov/ssle/damsafety/documents /ppg201108.pdf (data access 04.07.2017). [5] DAMS SECTOR, 2011, Estimating economic consequences for dam failures scenarios, US Department for Homeland Security, USA, 52 p., available 1262