Flowing into the heart of the Mojave Desert, the Mojave River
exists mostly underground. Surface channels are usually dry
absent occasional groundwater surfacing and flooding
from extreme weather events like El Niño.
Prado Dam – built in 1941 in
response to the Santa Ana
River’s flood-prone past – separates the river into its
upper and lower watersheds. After the devastation of the
deadly Los
Angeles Flood of 1938 that impacted much of Southern
California, it became evident that flood protection was woefully
inadequate, prompting the U.S. Army Corps of Engineers to
construct Prado Dam.
Completed in 1999, the Seven Oaks
Dam is a 550-feet-high earthen dam
on the Santa Ana River.
Its construction at the base of the San Bernardino Mountains was
a major component of the Santa
Ana River Mainstem Project, costing
$464 million and meant to protect the more than 2 million
citizens of Orange, Riverside and San Bernardino counties from
flooding. To
accomplish this, the dam releases only 7,000 cubic feet per
second (cfs) of the 85,000 cfs flowing into it, giving it
350-year
flood protection. The rest of this flood control project
consisted of raising the already existing Prado Dam downstream
and building additional channels.
Situated in southwest Riverside County near the Santa Ana
Mountains – about 60 miles southeast of Los Angeles – Lake
Mathews is a
major reservoir in Southern California.
The Colorado River Aqueduct, a
242-mile-long channel completed in 1941 by the Metropolitan Water
District of Southern California, carries water from the Colorado River to urban Southern
California. The aqueduct is one of three conveyance systems of
imported water to Southern California, the other two being the
California Aqueduct
and the Los Angeles
Aqueduct.
With a holding capacity of more than 260 billion gallons, Diamond
Valley Lake is Southern California’s largest reservoir. It sits
about 90 miles southeast of Los Angeles and just west of Hemet in
Riverside County where it was built in 2000. The offstream
reservoir was created by three large dams that connect the surrounding
hills, costing around $1.9 billion and doubling the region’s
water storage capacity.
As one of the most productive agricultural regions in the world,
the Imperial Valley
receives its water from the Colorado River via the
All-American Canal. Rainfall is scarce in the desert region at
less than three inches per year and groundwater is of little
value.
This issue looks at the dilemma of the shrinking Salton Sea. The
shallow, briny inland lake at the southeastern edge of California
is slowly evaporating and becoming more saline – threatening the
habitat for fish and birds and worsening air quality as dust from
the dry lakebed is whipped by the constant winds.
This 2-day, 1-night tour traveled through Inland
Southern California to learn about the region’s efforts in
groundwater management, recycled water and other drought-proofing
measures.
The Pacific Flyway is one of four
major North American migration routes for birds, especially
waterbirds, and stretches from Alaska in the north
to Patagonia in South America.
Each year, birds follow ancestral patterns as they travel the
flyway on their annual north-south migration. Along the way, they
need stopover sites such as wetlands with suitable habitat and
food supplies. In California, 95 percent of historic
wetlands have been lost, yet the Central Valley hosts some of the
world’s largest populations of wintering birds.
