1. Referencing and Analyzing Dams with the National Hydrography Dataset Jeff Simley, U.S. Geological Survey Bill Smith, U.S. Geological Survey

2. You're visitor 214447 since 01/25/1999 and 10 for today 08/04/2006

3. Dam Network upstream of dam blocked by dam Upstream navigation start Red: Everything upstream

5. 90 ft. NID dam location Edited dam location Indexed dam location Lake Dam address: Reach: 14010001002651 Measure: 99.929218

6. NID dam location is reasonable

7. Correct location for purposes of the NHD

8. Look at dam name and river name to determine where the dam belongs NID location

9. Look at NHD name and flow

10. Moved dam here to get proper indexing result

11. NID Dam location Assumed correct dam location

12. NID location Assumed location Use name to aide decision

13. Easily made assumption of correct dam location based on graphics Use name to confirm

14. Assume location simply by stream name Assume location at nearest spot with only stream name for guidance

15. No evidence of a dam

17. No evidence of dam

19. Non-indexable Dam location

20. NID dam right on stream looks like a hit, but no evidence of a dam in imagery

21. Three NID dams with no evidence in imagery

22. Assume dam belongs on lake NID location Indexed location Lake

23. NID location almost right on stream, but no evidence dam, except possibly nearby lakes

24. Dam NID location

25. Dam and lake not connected to NHD network No point in indexing this, but may want to improve location of dam

26. Can’t find the lake this dam belongs to

27. Make assumption of dam location based on name and graphics

28. Actually have dam in NHD to confirm location

29. Not enough information in location or stream name to Make decision Not enough information in location or stream name to make decision on correct location

30. Dam near wrong flowline for proper position

31. Dam has two outlets in NHD

32. Dam has two outlets in NHD

33. Dam has two outlets in NHD

34. Dam has two outlets on map, but only one in NHD

35. Two streams impounded by one dam

36. Two NID dams Two NHD flowlines Unclear what second dam does

37. Question of where exactly to index dams

38. Lake has two outlets

39. Create dummy dam Move NID dam

40. Moved dam and indexed Created dummy dam and indexed

41. Use flow direction to determine dam location at just one outlet point

42. Two outlets, but only one dam

43. Two dams represented by one NID dam

44. Corrected dam location Dummy dam Non-indexable dam

45. Indexing results with 50 ft tolerance All but non-connected dams have indexed

46. Properly indexed dams

47. Dams on Colorado River system upstream of Blue River confluence

48. Colorado River system dams with normal storage of over 1,000 acre-feet

49. Dams upstream of Blue River confluence with normal storage over 2,000 acre-feet

50. Dams upstream of Blue River confluence Built before 1960