Seite - 1263 - in Book of Full Papers - Symposium Hydro Engineering

online at https://www.yumpu.com/en/document/view/29287776/estimating- economic-consequences-for-dam-failure-scenarios (access 04.07.2017). [6] Decree No. 367/2005 Coll., Regarding technical requirements for water structures, (in Czech). [7] GRAHAM W.J., 1999, A procedure for estimating loss of life caused by dam failure, DSO-99-06, Dam Safety Office, U.S. Department of Interior, USBR, Denver, Colorado, USA, 43 p., available online at https://www.usbr.gov/ssle/ damsafety/techdev/dsotechdev/dso-99-06.pdf (data access 04.07.2017). [8] ICOLD, 1995, Dam failures statistical analysis, ICOLD Bulletin, 99, 76 p. [9] ICOLD, 2003, Dams and flood. Guidelines and cases histories, ICOLD Bulletin 125, 229 p. [10] MCCLELLAND D.M., BOWLES D.S., 2002, Estimating life loss for dam safety risk assessment – a review and new approach, US Army Corps of Engineers, Institute For Water Resources Report 02-R-3, 403 p., available online at http://www.iwr.usace.army.mil/portals/70/docs/iwrreports/02-r-3.pdf (access 04.07.2017). [11] ŘÍHA J. 2017, Determination of area affected by dam breach flood downstream of the Cholticky dam, (in Czech). SUMMARY Due to the stricter requirements on the hydraulic safety of the dams in the Czech Republic lot of hydrological and dam safety studies and also extensive remedial works at numerous dams are in progress. The reconstructions concern namely improvement of spillway capacity, adjusting of the dam crest and also clayey core elevation to withstand the check flood according present regulations. As the construction activities often call for provisional reduction of the dam crest elevation and opening of the spillway profile, the dam safety during the civil works has to be carefully analyzed. Usually, considerable drawdown of reservoir water level during the construction period is essential. This however may significantly interfere with main purposes of the dam and may also harm subsidiary effects of the scheme. In the paper the risk based approach is demonstrated at the safety analysis of the dams in the Czech Republic. The results of the analysis may also give some guidance for the optimal sequence of works at the site. 1263