31st session of EFC Working Party on the Management of Mountain Watersheds (), September 4-6, 2017

DEVELOPMENT OF WATER RESERVOIRS IN THE JIŘÍ KREMSA Povodí Labe, state enterprise ICOLD 2017 – Prague, Czech Republic Historical floods in the Jizera Mountains

Historical floods

1888 1897 1904 - Harcov 1906 - Bedřichov, Fojtka, Mlýnice 1909 - Mšeno 1915 - Bílá Desná, Souš 1958

1978 1982 – Josefův Důl

2000 2010 Fellowship for river regulation and dam construction 1900 – Fellowship in the Lužická Nisa river basin (supported 6 dams) 1902 – Fellowship on the river Černá Desná 1904 – Fellowship on the river Černá Desná extended for the river Kamenice and Bílá Desná 1904 – Construction of Harcov dam 1906 – Construction of Bedřichov, Fojtka and Mlýnice dam 1906 – Design of 2 reservoir systems in the Upper Jizera 1908 – Bílá Desná and Souš dam approved 1909 – Construction of Mšeno dam 1915 – Construction of Bílá Desná and Souš dam 1982 – Construction of Josefův Důl dam Dam failure of Bílá Desná in 1916 Drinking water supply

Josefův Důl dam Souš dam

Water supply: Liberec, , Hrádek n. N. Water supply: Jablonec n.N., Tanvald, Ž. Brod, Catchment area: 19,81 km2 Catchment area: 13,77 km2 Total volume: 22,62 mil.m3 Total volume: 7,48 mil.m3 Area: 130,10 ha Area: 68,75 ha Height: 43 m Height: 21 m Length: 360 m Length: 364 m Mean flow: 0,683 m3.s-1 Mean flow: 0,505 m3.s-1 Acid atmospheric deposition

• 1980s – catchments strongly affected by the acid atmospheric deposition. • 1990s – reduction of sulphur emissions → restoration activities started • 1996 – regular treatment of a water supply reservoir with agricultural limestone

DAMAGE OF THE SPRUCE FOREST LIMING IN THE SOUS RESERVOIR Water quality

Acid emissions HIGHER Concentration of Al Concentration of N-NO3 Concentration of phosphorus pH value Water transparency Water temperature Chlorofyl-a Zooplankton Fish LOWER Technology level of water treatment Water quality

ConcentrationConcentration of N of-No3 Aluminium in thein the reservoir reservoir (μg/l) (μg/l) Reservoir system in the Jizera Mountains

1906 1906 1982 1906

1915

1915

1904

1909 Flood protection

• transformation Q100 – Josefův Důl and Mšeno • transformation Q50 – Souš • transformation ≤Q20 – others

Floods in 2010 in the Jizera Mountains - precipitation 275 mm/day - extreme discharges in the Lužická Nisa - inflow to the Mlýnice exceed 1000-year flood Overflowing dam crest of the Mlýnice dam in 2010 Conclusion and discussion

Reducing peak discharges

Increasing Dam Water of flows in safety reservoirs dry season

Stable source of drinking water Thank you for your attention !