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2. End of show Near Shore Studies Ken Taylor Rick Susfalk Margaret Shanafield Desert Research Institute

3. Funding provided by: Nevada State Lands (Tahoe license plates) California Lahontan Regional Water Quality Control Board TRPA Funding provided by:

4. Near shore zone: Fast and local response to land use changes. C larity: greatest depth a Secchi disk is visible

5. turbidity chlorophyll temperature Sample inlet is 1 foot below surface

7. End of show UT4 Cebta Snapshot Day May 10, 2003 Incline Kings Beach Star Harbor Emerald Bay South Shore

8. End of show Cebta distance profile

9. End of show Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run July 11 2002 Calm Edgewood

10. 021022 Oct 22 2002 Calm Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

11. Nov 13 2002 2 inch snow on shore Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

12. 021218 Dec 18 2002 Calm and cold, Keys freeze Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

13. 030108 Jan 08 2003 2 feet of snow on shore Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

14. 030120 Jan 20 2003 Calm Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

15. 030125 Jan 29 2003 2 days after rain on lake shore snow Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

16. 030129 Jan 29 2003 6 days after rain on lake shore snow Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

17. 030217 Feb 17 2003 After 4 inch snow on shore Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

18. 030305 April 5 2003 calm Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

19. 030319 April 19 2003 After lake level rain Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

20. 030409 April 4 2003 After 6 inch snow on shore Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

21. 030513 May 13, 2003 Calm, spring run off Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

22. 030522 May 22 2003 Calm, spring run off Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

23. 030606 June 5 2003 Calm, end of run off Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

24. 030624 June 24 2003 After rain Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

25. July 03 2003 calm Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood

26. Collect particle sample on 0.1 micron filter Examine with scanning electron microscope

27. Boat photo 1 micron Upper Truckee outlet Organic

28. Boat photo Sand Harbor 1 micron Mineral

29. End of show Elemental composition of particles off Bijou Creek

30. End of show March 5, 2003: after calm, lke level snow melt Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood Algae Minerals

31. End of show March 5, 2003: after calm, lke level snow melt Tahoe Keys Upper Truckee Bijou Creek State Line Ski Run Edgewood Highest turbidity

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34. Near Shore Zone Only a few areas have a problem. Mineral particles from some, but not all, developed watersheds are the biggest problem.

35. Near Shore Zone Biggest problems occur during lake level snow melt and spring run off. How can we keep the small mineral particles out of the lake?

36. Littoral Zone Turbidity Threshold 1 NTU (Secchi clarity of ~4 m) away from streams 3 NTU (Secchi clarity of 1 to 2 m) for areas influenced by a stream. Is occasionally exceeded. Insignificant protection for lake. near shore zone clarity monitoring program is the ONLY way to determine the effectiveness of management actions on near shore clarity.

37. Near Shore Zone Clarity A near shore zone clarity monitoring program is the ONLY way to determine the effectiveness of management actions on near shore clarity.

38. Monitoring Identify location of problem areas to focus management actions. Determine trends to evaluate effectiveness of management actions. Whole lakeshore surveys in winter, spring and summer, to identify locations and spatial extent of problem areas. (Use the boat) Continuous measurement of major problem areas (7 to 10 areas), to determine temporal trends. (Use moored instruments)

39. Current Near Shore Monitoring: 4 times a year Calm conditions 9 locations Water depth of 25 m Cannot identify problem areas or trends. But… There is no near shore zone monitoring program. Mineral particles, not algae, is the biggest problem.

40. Suggested Monitoring Whole lakeshore surveys, to identify locations and spatial extent of problem areas. Continuous measurements, to determine temporal trends.

41. Near Shore Conclusions Several problem areas, caused by mineral particles from developed areas Ineffective regulatory threshold No way to determine effectiveness of management actions or trends

42. End of show Report is available at: http://tahoenearshore.dri.edu Lake level snow melt greatly increases turbidity of near shore waters by adding mineral particles to lake. Upper Truckee, Bijou Creek, Ski Run

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