City of los angeles general plan

_________________________________________________________________

CITY OF LOS ANGELES CONSERVATION ELEMENT

Adopted September 2001

II-37

settles in the canyon, impairing the spectacular views tourists travel

thousands of miles to see.

The Navajo Generating Station, owned by the Salt River Project

consortium, which includes the DWP, was identified as one source of the

haze. It is located near Page, Arizona, south and east of the Glen

Canyon National Park and at the northeast edge of Grand Canyon National

Park, 80 miles from the main Grand Canyon visitor center. This coal

fired facility was constructed in 1975, before sulfur dioxide scrubbers

became available.

A series of studies were conducted (1987-89) to identify the sources of

Grand Canyon haze. Chemical tracers used in a National Park Service

study, partially funded by the consortium, identified some of the haze

as originating from the Navajo plant. Based on the study, the

Environmental Defense Fund sued the EPA for failing to enforce the

visibility provision of the Clean Air Act. An EPA study concluded that

in the winter, between November and March, haze reduced visibility at

the Grand Canyon from 150 miles to under 10 miles and that the Navajo

plant was a significant source. A verification study by the National

Academy of Sciences found that the winter haze was caused primarily by

automotive vehicle exhausts, that the Navajo plant "contributed

significantly" and that ore smelters, pollution from near and distant

urban areas (including Mexico) and other sources also contributed.

Based on the study, the EPA (1989) contended that the Navajo plant

contributed 40% of the introduced haze. It issued an order requiring

the consortium to install scrubbers. 

The consortium agreed (1991) to reduce visibility impacts by installing

scrubbers designed to remove 90% of the sulfur dioxide emissions. These

were in service by August 1999. The historic agreement marked the first

time the EPA had enforced the Clean Air Act provisions requiring

protection of visibility at national parks and wilderness areas. For

the first time it acted solely to protect visibility and aesthetic

values, not health quality. The scrubbers may improve visibility at the

Grand Canyon by 7% on an average winter day. They are not expected to

improve visibility during summer months when air pollution from the Los

Angeles basin is the principal source of Colorado Plateau haze. 

Another potential source of sulfur dioxide pollution affecting the

Colorado Plateau region is the Mohave Generating Station in Laughlin,

Nevada. The station is operated by the Southern California Edison

Company and is partially owned by the DWP. It was constructed in 1971

and has partial emission controls. As a result of negotiations, which

were concluded in 1999 to settle pending litigation, an agreement was

reached requiring the station to install additional emission controls

---

_________________________________________________________________

CITY OF LOS ANGELES CONSERVATION ELEMENT

Adopted September 2001

II-38

by 2005, or to cease operation in its present form, e.g., coal fired

facility.

Owens Lake and Owens Valley. City of Los Angeles and federal ownership

of almost all the lands in the Owens Valley, including mountain slopes

on both sides of the valley, has kept the area free from commercial

development, providing an almost unbroken view from Highway 395 of the

magnificent Sierra Nevada and White Mountains. Public ownership also

has enabled public access for hiking, hunting, fishing and winter

sports. But the city's diversion of the Owens River waters before they

reach Owens Lake and tapping of underground valley water have

contributed to impaired air quality and other impacts on the valley.

Owens Lake. The air quality issue associated with the drying of the

lake, primarily due to water diversion, resulted in dust mitigation

measures. These, in turn, resulted in side benefits to habitat and

wildlife enhancement. The majority of Owens Lake (95%) is owned by the

State of California and is under the authority of the State Lands

Commission. 

The lake is a remnant of a large prehistoric freshwater lake which at

one time extended some 60 miles up and down Owens Valley, reaching a

depth of 320 feet. By the time settlers entered the valley in the mid-

19th century, Owens Lake had shrunk to a fraction of that size, to a

shallow, salty desert sink. Dissolved minerals and salts, which had

flowed into the lake for millennia, had become so concentrated by

evaporation that only algae, brine shrimp, brine flies and other

primitive life could survive. 

By 1905, diversion of Owens River water by local farmers and an

extended drought shrank the lake even more. Shrinkage was accelerated

by the Los Angeles River Aqueduct. Completed in 1913, the aqueduct

diverted most of the remaining river water before it reached the lake.

By the late 1920s, the lake had become a dry lake, one of the largest

dry lakes in California. Its rapid shrinking had left shallow brine

pools within the dry lake bed and springs and seeps around its edges.

These wetlands supported remnants of the primitive marine ecosystem,

some of which remain to this day.

Due to the accelerated drying of the lake caused by the aqueduct

diversion, an alkaline crust of dissolved and crystallized minerals and

salts was created over much of the lake bed. Winds and shifting sands

lacerated the crust, resulting in dust becoming airborne during windy

periods. 

---