DAMS

1. DAMS

2. TERMINOLOGY for DAMS • Dam.........................................................baraj • Small dam...............................................bent veya gölet • Reservoir................................................hazne veya göl alanı • Leakage..................................................su kaçağı • Seepage..................................................sızma • Storage...................................................depolama • Coffer dam..............................................batardo • Upstream coffer dam.............................memba batardosu • Downstream coffer dam........................mansap batardosu • Core.........................................................baraj çekirdeği • Filter.........................................................filtre veya geçirgen katman • Diversion tunnel.....................................derivasyon tüneli – çevirme tüneli • Rip-rap.....................................................koruyucu kaya dolgu • Cut-off.....................................................hendek • Toe-drain.................................................topuk drenajı • Right side................................................sağ yan – sağ sahil • Left side..................................................sol yan – sol sahil

3. River side.....................................nehir içi • Butress.........................................payanda • Foundation...................................temel • Embankment................................sedde • Base-width....................................taban genişliği • Crest..............................................tepe • Cut-off trench...............................saplama hendeği • Expansion joint............................genişleme derzi (dilatasyon) • Spillway........................................dolusavak • Gravity dam..................................ağırlık barajı • Tail water......................................çıkan su • Head water...................................giren su • Arch dam......................................kemer baraj • Abutment......................................yan dayanak • Multiple arch dam........................çok kemerli baraj veya payandalı baraj • Extrados.......................................dış yüzey • Intrados........................................iç yüzey

4. Parapet...............................................korkulukParapet...............................................korkuluk • Rock fill dam......................................kaya dolgu baraj • Compacted rock fill...........................sıkıştırılmış kaya dolgu • Dumped rock fill................................dökme kaya dolgu • Foot wall.............................................topuk duvarı • Earth dam...........................................toprak baraj • Watertight core..................................geçirimsiz çekirdek • Watertight diaphram.........................geçirimsiz perde • Retaining wall....................................istinat (dayanma) duvarı • Hard ground......................................sağlam zemin • Impervious ground...........................geçirimsiz zemin • Grout curtain.....................................enjeksiyon (harçlama) perdesi • Overburden.......................................sıyrılacak katman • Bedrock.............................................yerli kaya

5. DISTRIBUTION of WATER RESOURCES

7. In Turkey, 536 large dams have been built and being operated. On the other hand, Small Hydraulic Works Department has built 42 small dams. • Here, 50 storage facilities that are not considered as dam due to their low heights (<15m) and low storage capatcities (<2 hm3) have not been taken into account. • By now, construction of 100 dams and hydroelectric powerplants is going on.

8. Definition • A dam is a structure which prevents the flow of water and accumulates it in a reservoir Karakaya Dam/Diyarbakır Atatürk Dam/Şanlıurfa

9. Needs for Dam Construction • Drinking and domestic water supply • Flood control • Irrigation • Industrial water supply • Hydroelectric energy production • Retention and control of sediments and Inland navigation, Improvement of water quality, Fish Farming, Recreation facilities

10. BREAKDOWNbyPURPOSE ofDAMSinEUROPE

11. CLASSIFICATION OF DAMS

12. ACCORDING to the SIZE of the DAM • Large (Big) dam • Small dam • International Commision on Large Dams, (ICOLD) assumes a dam as big when its height is bigger than 15m. • If the height of the dam is between 10m and 15m and matches the following criteria, then ICOLD accepts the dam as big: • If the crest length is bigger than 500m • If the reservoir capacity is larger than 1 million m3 • If the flood discharge is more than 2000 m3/s • If there are some difficulties in the construction of foundation

13. ACCORDING to HEIGHT of DAM • High Dam or Large Dam • If the height of the dam is bigger than 100m • Medium Dam • If the height of the dam is between 50m and 100m • Low Dam or Small Dam • If the height of the dam is lower than 50m

14. ACCORDING to the STATICAL DESIGN of DAM BODY • Gravity Dams (Sarıyar, Çubuk I, Kemer, Sır II Karacaören II) • Arch Dams (Gökçekaya, Karakaya, Oymapınar, Gezende) • Butress Dams (Elmalı II) • Embankment Dams (Atatürk, Seyhan, Aslantaş) • Composite Dams (Keban)

15. GRAVITY DAMS • Gravity Dams use their triangular shape and the sheer weight of their rock and concrete structure to hold back the water in the reservoir. Sarıyar Dam – Sakarya River; Height= 90 m Reservoir Capacity= 1.9 billion m3

17. ARCH DAMS • Arch Damsutilize the strength of an arch to displace the load of water behind it onto the rock walls that it is built into. Karakaya Dam – Fırat River; Height= 173 m Reservoir Capacity= 9,5 billion m3

18. BUTRESS DAMS • Buttress Dams use multiple reinforced columns to support a dam that has a relatively thin structure. Because of this, these dams often use half as much concrete as gravity dams Elmalı II – Göksu River; Height= 42.5 m Reservoir Capacity= 10 million m3

19. EMBANKMENT DAMS (Rock Fill or Earth Fill Dams) • They are mostly composed of natural materials such as, clay, sand, gravel etc... • Impervious core is placed in the middle of the embankment body • Generally riprap is used to control erosion Atatürk Dam – Fırat River; Height= 169 m; Reservoir Capacity= 48,7 billion m3

20. COMPOSITE DAMS • Composite dams are combinations of one or more dam types. Most often a large section of a dam will be either an embankment or gravity dam, with the section responsible for power generation being a buttress or arch. Keban Dam – Fırat River; Height= 163 m; Reservoir Capacity= 31 billion m3 Gravity & Rock Fill

21. ENGINEERING GEOLOGICAL STUDIES for DAM CONSTRUCTION

22. 1. RECONNAISSANCE STUDY • Evaluation of the data having at archives of MTA, DSI, EIE, Universities,......etc • Field investigation for limited time (Reconnaissance Study) • Some maps in small scale, for example 1/25.000 or 1/50.000 • Some hydraulic data about • Basin • Precipitation area • Runoff, maximum discharge {Q=R/t (m3/s)} • Modulus of Runoff (R/t/m2 ~ R/t/km2) • Some approach to the reservoir area, dam site and type of dam and height of dam...etc • Photogeological studies • A preliminary report

23. 2. PRELIMINARY STUDIES at the RESERVOIR AREA and DAM SITE • Dam site investigations 1. Location of dam axis 2. Location of diversion tunnel 3. Location of spillway 4. Location of powerhouse...etc • Geological studies • Geophysical surveying • Underground investigations 1. Boreholes 2. Investigation galleries 3. Pitholes • Surveying for materials 1. Field surveying 2. Laboratory tests

24. Slope stability investigations • Earthquake hazard & risk analysis • Environmental studies • Leakage possibilities from reservoir area • Leakage possibilities from dam site • Erosion, sedimentation & siltation

25. DETAILED INVESTIGATION at DAM SITE • Topographic surveyings • Geological mappings 1/5000 – 1/1000 or 1/500 • Underground explorations Boreholes, adits....etc • Hydrogeological studies • Slope stability analysis

26. FACTORS AFFECTING to the DAM TYPE SELECTION • Topography • Geology • Bearing capacity of the underlying soil • Foundation settlements • Permeability of the foundation soil • Material availability • Spillway position • Earthquakes • Safety • Height • Aesthetic view • Qualified labour • Cost

27. FACTORS AFFECTING to the PLACE of the DAM AXIS • Topography • Geology • Materials • Spillway location availability • Derivation • Sediments in the flowing water • Water quality • Expropriation costs • Earthquake possibility • Downstream water rights

28. RIVER BASINS in TURKEY Turkey has been separated into 26 main river basins for the hydrological studies.

29. ENVIRONMENTAL IMPACTS OF DAMS

30. ENVIRONMENTAL IMPACTS of CONSTRUCTION PHASE of DAMS • River pollution • Erosion • Loss of aesthetic view • Air pollution • Noise pollution • Dust

31. ENVIRONMENTAL IMPACTS of RESERVOIRS • Loss of land • Habitat Destruction : • The area that is covered by the reservoir is destroyed, killing whatever habitat existed there beforehand. • Loss of archeological and histrorical places • Loss of mineral deposits • Loss of special geological formations • Aesthetic view reduction • Sedimentation • Change in river flow regime and flood effects • Reservoir induced seismicity • Change in climate and plant species

32. EFFECTS of DAMS to WATER QUALITY • Change in temperature • Turbidity • Dissolved gases in the water • Water discharged from the spillway contains 110-120% saturated nitrogen. This amount may be destructive for fish life. • Eutrophication • It means increase in vegetation. If moss and other plants exist in water, quality of that water gets worse.

33. SOME DAMS from SPACE