1. The Salton Sea By: Christine Yafuso

2. Background Located in Southeastern California Located in Southeastern California About 1000 km 2 in size About 1000 km 2 in size Largest lake in California Largest lake in California Formed between 1904-1907 by accidental flooding of Colorado River (started as freshwater) which eventually filled the Salton Basin Formed between 1904-1907 by accidental flooding of Colorado River (started as freshwater) which eventually filled the Salton Basin Repository for agricultural wastewater Repository for agricultural wastewater Picture: Salton Sea Authority, California Government 2000

3. Inflow Greatest (78%) from major surrounding rivers: Alamo & New Greatest (78%) from major surrounding rivers: Alamo & New Agriculture accounts for 8% Agriculture accounts for 8% Ground Water only 4% Ground Water only 4% Picture: Salton Sea Authority, California Government 2000

4. Characteristics Chemical & Physical Chemical & Physical –Nutrients –Metals –Organic Compounds Ecological Ecological –Fish –Birds Picture: Salton Sea Authority, California Government 2000

5. Salinity Currently at about 45 ppt Currently at about 45 ppt Causes Causes –No surface outflow –Evaporation –Increased input of saline –Increased input of nutrient rich agricultural drainage water Picture: Riedel & Costa-Pierce 2002

6. Dissolved Oxygen Low concentrations Low concentrations Decreases with depth Decreases with depth Rivers flowing into sea also have low concentrations Rivers flowing into sea also have low concentrations –Average percentages of saturation of dissolved oxygen concentrations for 2 main rivers: Alamo (77.3) & New (66.2) Main Causes Main Causes –High eutrophic system –Frequent algae blooms Picture: Barnum et al 2002

7. Nitrogen & Selenium Enter Salton Sea (by way of rivers) in high concentrations Enter Salton Sea (by way of rivers) in high concentrations N from chemical fertilizers N from chemical fertilizers Se from water used for irrigation Se from water used for irrigation Removal by anoxic sediment from floor Removal by anoxic sediment from floor Result: Lower concentrations of N & Se, however, produces noxious odor Result: Lower concentrations of N & Se, however, produces noxious odor

8. Problems Major cause: No Outflow! Major cause: No Outflow! Results in: Results in: –High salinity –Low dissolved oxygen levels –Harmful odors (From removed N & Se) Leads to: Leads to: –Ecological crisis…

9. Effects on Fish 1999: 7.6 mil tilapia and croakers died 1999: 7.6 mil tilapia and croakers died Other contributing factors Other contributing factors –Toxic ammonia contents & temperature stresses Picture 1: Gulf croakers die-offs Picture 2: Tilapia die-offs Cohn 2000 Desai 2000 Cohn 2000 Desai 2000

10. Effects on Birds 1996: About 15,000 birds died-10,000 of them pelicans 1996: About 15,000 birds died-10,000 of them pelicans Cause: Disease Cause: Disease –Avian botulism (bacterial infection): toxin produced by bacteria at high temps & low levels of dissolved oxygen –Paralyzes muscles Picture: Slack 1997

11. Restoration Alternatives 1) Ecological 1) Ecological –Fish Harvesting –Fish & Wildlife Disease Control –Wetland Reclamation 2) Technical 2) Technical –Displacement Dikes –Enhanced Evaporation Systems –Solar Ponds 3) Societal 3) Societal –Enhance Infrastructure –Improve economic status

12. Goals Maintain as agricultural drainage reservoir Maintain as agricultural drainage reservoir Restore wildlife & habitat Restore wildlife & habitat Encourage more recreational use Encourage more recreational use Suitable for economical development Suitable for economical development