Tereno Advisory Board Meeting Sept. 2001 Excursion: Reservoir

Karsten Rinke Department of Lake Research Page 2 The Rappbode Reservoir Observatory

ƒ located at Rappbode reservoir ( Mountains, ) ƒ Investment: about 500.000 € ƒ Countinuous monitoring of nutrient and carbon fluxes and corresponding ecosystem dynamics

Rappbode Reservoir ƒ One main reservoir and 3 pre-dams ƒ Drinking water supply for over 1 Mio people ƒ Surface area: 395 ha ƒ Volume: 113 Mio m3 ƒ Max. depth: 89 m ƒ mesotrophic

Photo: André Künzelmann (UFZ)

Page 3 The Rappbode Reservoir Observatory main reservoir three pre-dams 4 inflow stations Real-time & continuous measurement of - temperature - conductivity - turbidity -nitrate -DOC and event-dependent water sampling by automated water samplers Talsperrenbetrieb Sachsen-Anhalt

Page 4 The Rappbode Reservoir Observatory

3 connecting stations Real-time & continuous measurement of - temperature - conductivity - turbidity -nitrate -DOC - oxygen - chlorophyll

Talsperrenbetrieb Sachsen-Anhalt

Page 5 The Rappbode Reservoir Observatory

1 offshore station Meteorological buoy (wind, temperature, humidity, radiation) Real-time & continuous measurement of - temperature - conductivity - turbidity -nitrate -DOC - oxygen - chlorophyll Talsperrenbetrieb Sachsen-Anhalt

Page 6 Example: Warme 10-22. Sept. 2011

70 water level water temperature 190 SAC254 conductivity 60 170 50 150 40 130

30 110

20 90

10 70

0 50 8.9.11 10.9.11 12.9.11 14.9.11 16.9.11 18.9.11 20.9.11 22.9.11 24.9.11 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00

Page 7 Nutrient elimination in pre-dams

CO2 CO2

CO 2 SRP DOC DOC POC SRP PP ALGAE PP POC CO2

Phosphorous (P) water level in the the pre-dam Carbon (C) water level in the main dam Sedimentation Page 8 DOC = Dissolved organic carbon

Poolgrößen DOC Ozean 700 Gt

CO2 Atmosphäre 750 Gt Terrestrische Pflanzen 600 Gt

Stoffflüsse Seesedimente 0.04 Gt a-1 Moore 0.1 Gt a-1 Talsperren 0.6 Gt a-1

Page 9 Research focus: rising levels of DOC* *DOC=dissolved organic carbon

DOC-levels in Rappbode reservoirs nearly doubled over the past 20 years

Data: Fernwasserversorgung Elbaue-Ostharz

Page 10 Problems in the waterworks: stability of flocculation, sludge production & desinfection byproducts, …

Raw water after flocculation

Purified water Raw water

Sludge Source: LTV Sachsen

Page 11 DOC-Eintrag durch hydrologische Extremereignisse Heavy rainfall in Kyrill 2007 & late summer 2002 Heavy rainfall in 60 late summer 2007 Eckertalsperre (NI)

50 TS Eibenstock (SN) Aabachtalsperre (NW) 40 Heavy rainfall in late summer 1998 30

SAK_254 (1/m) 20

10

0 Jan. 94 Jan. 95 Jan. 96 Jan. 97 Jan. 98 Jan. 99 Jan. 00 Jan. 01 Jan. 02 Jan. 03 Jan. 04 Jan. 05 Jan. 06 Jan. 07 Jan. 08 Jan. 09 Quelle: LTV Sachsen Page 12