1. Topics for today Dams - Geography –Elwha River Dams –Glen Canyon Dam –Colorado Compact (1922) Ground water Chapter IX pp 260-266 Importance Processes –Hydraulic gradient –Permeability Ground water pollution Ground water surface water interactions –Gaining Streams –Loosing streams Supply and demand Focus study 9-2 Subsidence

2. DAMS AN D DAM REMOVAL

3. Washington state DAMS

4. Grand Coulee Dam

7. Elwha River Dam

9. Glen Canyon Dam

11. Colorado Pike Meadow

13. Reading discussion “Science and Values in River Restoration in the Grand Canyon” Deciding what to do with the Grand Canyon ecosystem rehabilitated/or not?

15. 25,000 float the Canyon every year

16. Razorback sucker (Xyrauchen texanus) Humpback chub (Gila cypha) Endemic endangered fish species

17. Kanab ambersnail

18. Willow flycatcher

19. Rainbow trout

23. Colorado Compact, 1922 Why put all this effort in saving a bunch of sucker fish? How are we restoring for? Fish? Rafters? Table 3

25. Management approaches 1.Traditional river management 2.Naturalized ecosystem 3.Simulated natural ecosystem 4.Substantially restored river 5.Full restored river

26. Traditional river management Accepts the river as a transformed ecosystem Maximizes power revenues Ecological integrity is a second value

27. Naturalized ecosystem Blend of the old and the new Management with minor flow releases Mixture of native and introduced organisms

28. Simulated natural ecosystem Simulated some pre-dam ecological processes Dan releases that resemble pre dam conditions Aim to restore sand bars and fish habitat Seasonal affect of energy production

29. Substantially restored river Restore pre-dam hydrological variability (more sediment transport) Construction of facilities to transport sediment from the lake downstream Built of structures that allow releases of water at different temperatures Constrains in power production and water availability to lower basins

30. Full restored river Ambiguous management goal Removal of flow regulation Removal of the dam Eradication of non-native species No power production

31. Dilemmas.. Unvegetated bars versus riparian vegetation Reduction of marsh area …. Is lost of biodiversity acceptable to restore pre-dm conditions?