BirdWatching USA – September-October 2019

38 BirdWatching • September/October 2019

f looding, forming a lake roughly
35 miles long and 15 miles wide.
Afterward, settlement in the area was
spurred by commercial salt excavation
and the promise of rich farmland.
Over the years, the Salton Sea has
f looded and receded a number of times,
to the detriment of small fishing and
recreational communities that sprung
up and remain along the shoreline.
Today’s sea is 227 feet below sea level,
covers 380 square miles, and has an
average depth of 31 feet.
The sea’s watershed covers nearly
7,500 miles and is fed by three small
rivers: the Whitewater at the northern
end, and the Alamo and New rivers at
the southern end. All three rivers, the
principal source of water replacement to
the sea, carry agricultural and storm
runoff.
It’s commonly thought that the sea’s
basin is the repository of not only
agricultural runoff with fertilizers and
pesticides but also raw sewage. The
New River has been singled out as a
primary offender, with raw waste
originating in the municipality of
Mexicali, Mexico, dumped into the
river. Some estimates place the
dumping as high as 20 million gallons
of sewage daily because of equipment
breakdowns at the city’s treatment
plant, and in past years the U.S.

government has given the Mexicali

municipality financial aid to correct

the situation.

But the importance of the New

River’s pollutant role may be overstated.

It accounts for only 30 percent of the

Salton Sea’s water, and routine tests have

found that water traveling from

Mexicali to the sea has been diluted and

naturally treated, leaving it with a

similar quality to its sister tributary, the

Alamo River, used to irrigate Imperial

and Coachella Valley groves and

vegetable fields. According to the Salton

Sea Authority, an oversight coalition of

municipal governments and water

districts, routine water tests also

confirm that there is no significant level

of pesticides in the sea.

Greater culprits plague the sea than

the New River. Salinity and nutrient

saturation threaten the sea’s viability

and the survival of the millions of fish

and birds that it feeds.

TOO MUCH SALT

The saltiness of the sea directly affects

aquatic organisms and fish upon which

the many species of waterfowl and

shorebirds rely on as a food source. The

Salton Sea is getting saltier by the day.

The soil basin of the sea has a heavy salt

content that leaches directly into water

and into agricultural drainage f luids

before entering the sea. The Colorado

River, a naturally salty water source, is

used for irrigation and nutrients applied

to agricultural fields as fertilizers

contribute more salt to the sea.

The Salton Sea receives nearly

4 million tons of salt each year, and it’s

now twice as salty as the Pacific Ocean.

GOLDEN LIGHT: An American Avocet wades in
the shallows. The shorebird species has found
favorable conditions at the sea in recent years.

RELIABLE: The Salton Sea is the only

place in the U.S. where Yellow-footed Gull

is regularly seen. The species primarily

lives along Mexico’s Gulf of California.

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