Download The Salton Sea

The Salton Sea
By: Christine Yafuso
Background
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Located in Southeastern
California
About 1000 km2 in size
Largest lake in California
Formed between 1904-1907 by
accidental flooding of
Colorado River (started as
freshwater) which eventually
filled the Salton Basin
Repository for agricultural
wastewater
Picture: Salton Sea Authority, California
Government 2000
Inflow
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Greatest (78%) from
major surrounding
rivers: Alamo & New
 Agriculture accounts for
8%
 Ground Water only 4%
Picture: Salton Sea Authority, California
Government 2000
Characteristics
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Chemical & Physical
– Nutrients
– Metals
– Organic Compounds
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Ecological
– Fish
– Birds
Picture: Salton Sea Authority, California
Government 2000
Salinity
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Currently at about
45 ppt
 Causes
–
–
–
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No surface outflow
Evaporation
Increased input of saline
Increased input of
nutrient rich agricultural
drainage water
Picture: Riedel & Costa-Pierce 2002
Dissolved Oxygen
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Low concentrations
Decreases with depth
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)
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Main Causes
– High eutrophic system
– Frequent algae blooms
Picture: Barnum et al 2002
Nitrogen & Selenium
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Enter Salton Sea (by way of rivers) in high
concentrations
 N from chemical fertilizers
 Se from water used for irrigation
 Removal by anoxic sediment from floor
 Result: Lower concentrations of N & Se,
however, produces noxious odor
Problems
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Major cause: No Outflow!
 Results in:
– High salinity
– Low dissolved oxygen levels
– Harmful odors (From removed N & Se)
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Leads to:
– Ecological crisis…
Effects on Fish
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1999: 7.6 mil tilapia and croakers died
 Other contributing factors
– Toxic ammonia contents & temperature stresses
Picture 1: Gulf croakers die-offs
Cohn 2000
Picture 2: Tilapia die-offs
Desai 2000
Effects on Birds
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1996: About 15,000 birds
died-10,000 of them
pelicans
Cause: Disease
– Avian botulism (bacterial
infection): toxin produced by
bacteria at high temps & low
levels of dissolved oxygen
– Paralyzes muscles
Picture: Slack 1997
Restoration Alternatives
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1) Ecological
– Fish Harvesting
– Fish & Wildlife Disease Control
– Wetland Reclamation
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2) Technical
– Displacement Dikes
– Enhanced Evaporation Systems
– Solar Ponds
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3) Societal
– Enhance Infrastructure
– Improve economic status
Goals
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Maintain as agricultural
drainage reservoir
 Restore wildlife &
habitat
 Encourage more
recreational use
 Suitable for economical
development