1. Reservoir Paleolimnology Paul Gremillion, Ph.D., P.E. Civil & Environmental Engineering Northern Arizona University paul.gremillion@nau.edu Nelson Reservoir, Summer 2004

2. Unique Reservoir Characteristics

3. Paleolimnology Can Reveal Rates of sedimentation Changes in distribution of sediment Past primary productivity Past episodes of oxygen depletion Changes in local terrestrial vegetation Fire histories Atmospheric pollution deposition

4. Acoustic Surveys Side Scan Sonar Seismic Sub-bottom Profiling

5. Side Scan Sonar The package freighter Montana (before) http://oceanexplorer.noaa.gov/projects/thunderbay01/shipwrecks/media/montana.html

6. Side Scan Sonar The Montana (after)

7. http://www.indepthconsulting.com/B29/B29Imaging.htm

13. Sediment Core Analysis ObjectiveAnalyte / Proxy Chronology 137 Cs or 239 Pu~ 50 yrs 210 Pb~150 yrs 14 C~100 – 15k yrs Event-based chronology Primary Productivity Diatoms Biogenic silica 13 C (in some systems) Anoxia Ratios of redox-sensitive metals Molybdenum stable isotopes Benthic invertebrates Fire Charcoal Magnetic susceptibility

14. Sediment Core Analysis ObjectiveAnalyte / Proxy Hydrology Magnetic susceptibility Inorganic ion ratios Particle size distributions Sediment Redistribution Acoustic surveys 137 Cs or 239 Pu inventories Particle size distributions Ecosystem Assemblages Pollen Atmospheric Pollutants Chemical extraction + elemental analysis

15. Carnero Lake, Summer 2004

17. Plutonium

18. Total Mercury

20. Conclusions Arid-lands reservoirs are excellent recorders of atmospheric pollutants Sediment disturbance has not been severe in reservoirs cored to date Acoustic surveys and radioisotope inventories are promising techniques for sediment accumulation and redistribution A suite of paleolimnological techniques is available to detect past conditions in arid- lands reservoirs