SALTON SEA IN CALIFORNIA
Dee Finney's blog
start date July 20, 2011
today's date September 12, 2012
page 264
TOPIC: THE SALTON SEA (CALIFORNIA)
Actually, no. Methane itself does not have an especially
pungent
odor, making it nearly impossible to detect leaks via sense of
smell alone. Thus, a foul-smelling compound is added to methane before it's
used commercially, for safety reasons.
Read more:
http://wiki.answers.com/Q/Does_methane_have_a_pungent_odor#ixzz26GNekHNa
The odor of rotten eggs is caused by Hydrogen sulfide (H2S) , a poisonous, colorless flammable deadly gas, that can explode. This is what is added to the Methane we call 'natural gas' which we use in our homes.
The Salton Sea is a shallow, saline, endorheic rift lake located directly on the San Andreas Fault, predominantly in California's Imperial Valley.
The lake occupies the lowest elevations of the Salton Sink in the Colorado Desert of Imperial and Riverside counties in Southern California. Like Death Valley, it is below sea level. Currently, its surface is 226 ft (69 m) below sea level. The deepest area of the sea is 5 ft (1.5 m) higher than the lowest point of Death Valley. The sea is fed by the New, Whitewater, and Alamo rivers, as well as agricultural runoff drainage systems and creeks.
The Sea was created by a flood in 1905, in which water from the Colorado River flowed into the area. While it varies in dimensions and area with fluctuations in agricultural runoff and rainfall, the Salton Sea averages 15 mi (24 km) by 35 mi (56 km). With an average area of roughly 525 sq mi (1,360 km2), the Salton Sea is the largest lake in California. Average annual inflow is 1,360,000 acre·ft (1.68 km3), which is enough to maintain a maximum depth of 52 ft (16 m) and a total volume of about 7,500,000 acre·ft (9.3 km3).
The lake's salinity, about 44 g/L, is greater than that of the waters of the Pacific Ocean (35 g/L), but less than that of the Great Salt Lake (which ranges from 50 to 270 g/L). The concentration increases by about 1 percent annually.[1]
Geologists estimate that for 3 million years, at least through all the years of the Pleistocene glacial age, the Colorado River worked to build its delta in the southern region of the Imperial Valley. Eventually, the delta had reached the western shore of the Gulf of California (the Sea of Cortez/Cortés), creating a massive dam that excluded the Salton Sea from the northern reaches of the Gulf. Were it not for this dam, the entire Salton Sink along with the Imperial Valley, including most of the area occupied by Anza-Borrego Desert State Park, would all be submerged, as the Gulf would extend as far north as Indio.[2]
As a result, the Salton Sink or Salton Basin has long been alternately a fresh water lake and a dry desert basin, depending on random river flows and the balance between inflow and evaporative loss. A lake would exist only when it was replenished by the river and rainfall, a cycle that repeated itself countless times over hundreds of thousands of years – most recently when the lake was recreated in 1905.[3]
There is evidence that the basin was occupied periodically by multiple lakes. Wave-cut shorelines at various elevations are still preserved on the hillsides of the east and west margins of the present lake, the Salton Sea, showing that the basin was occupied intermittently as recently as a few hundred years ago. The last of the Pleistocene lakes to occupy the basin was Lake Cahuilla, also periodically identified on older maps as Lake LeConte, and the Blake Sea, after American professor and geologist William Phipps Blake.
Once part of a vast inland sea that covered a large area of Southern California, the endorheic Salton Sink was the site of a major salt mining operation.[4] Throughout the Spanish period of California's history the area was referred to as the "Colorado Desert" after the Colorado River. In a railroad survey completed in 1855, it was called "the Valley of the Ancient Lake". On several old maps from the Library of Congress, it has been found labeled "Cahuilla Valley" (after the local Indian tribe) and "Cabazon Valley" (after a local Indian chief – Chief Cabazon). "Salt Creek" first appeared on a map in 1867 and "Salton Station" is on a railroad map from 1900, although this place had been there as a rail stop since the late 1870s.[5]
In 1900, the California Development Company began construction of irrigation canals to divert water from the Colorado River into the Salton Sink, a dry lake bed. After construction of these irrigation canals, the Salton Sink became fertile for a time, allowing farmers to plant crops.
Within two years, the Imperial Canal became filled with silt from the Colorado River. Engineers tried to alleviate the blockages to no avail. In 1905, heavy rainfall and snowmelt caused the Colorado River to swell, overrunning a set of headgates for the Alamo Canal. The resulting flood poured down the canal and breached an Imperial Valley dike, eroding two watercourses, the New River in the west, and the Alamo River in the east, each about 60 miles (97 km) long.[6] Over a period of approximately two years these two newly created rivers sporadically carried the entire volume of the Colorado River into the Salton Sink.[7]
The Southern Pacific Railroad attempted to stop the flooding by dumping earth into the canal's headgates area, but the effort was not fast enough, and as the river eroded deeper and deeper into the dry desert sand of the Imperial Valley, a massive waterfall was created that started to cut rapidly upstream along the path of the Alamo Canal that now was occupied by the Colorado. This waterfall was initially 15 feet (4.6 m) high but grew to a height of 80 feet (24 m) before the flow through the breach was finally stopped. It was originally feared that the waterfall would recede upstream to the true main path of the Colorado, attaining a height of up to 100 to 300 feet (30 to 91 m), from where it would be practically impossible to fix the problem. As the basin filled, the town of Salton, a Southern Pacific Railroad siding, and Torres-Martinez Indian land were submerged. The sudden influx of water and the lack of any drainage from the basin resulted in the formation of the Salton Sea.[8][9]
The continuing intermittent flooding of the Imperial Valley from the Colorado River led to the idea of the need for a dam on the Colorado River for flood control. Eventually, the federal government sponsored survey parties in 1922 that explored the Colorado River for a dam site, ultimately leading to the construction of Hoover Dam in Black Canyon, which was constructed beginning in 1929 and completed in 1935. The dam effectively put an end to the flooding episodes in the Imperial Valley.
The Salton Sea enjoyed some success as a resort area, with Salton City, Salton Sea Beach, and Desert Shores on the western shore and Desert Beach, North Shore, and Bombay Beach built on the eastern shore in the 1950s. The town of Niland is located 3 km southeast of the Sea as well. The evidence of geothermal activity is also visible. There are mudpots and mud volcanoes on the eastern side of the Salton Sea.[10]
The Salton Sea has been termed a "crown jewel of avian biodiversity" (Dr. Milt Friend, Salton Sea Science Office). Over 400 species have been documented at the Salton Sea. The Salton Sea supports 30% of the remaining population of the American white pelican.[11] The Salton Sea is also a major resting stop on the Pacific Flyway. On 18 November 2006, a Ross's gull, a high Arctic bird, was sighted and photographed there.[12]
Avian population
The Salton Sea has been termed a "crown jewel of avian biodiversity" (Dr. Milt Friend, Salton Sea Science Office). Over 400 species have been documented at the Salton Sea. The Salton Sea supports 30% of the remaining population of the American white pelican.[11] The Salton Sea is also a major resting stop on the Pacific Flyway. On 18 November 2006, a Ross's gull, a high Arctic bird, was sighted and photographed there.[12]
The lack of an outflow means that the Salton Sea is a system of accelerated change. Variations in agricultural runoff cause fluctuations in water level (and flooding of surrounding communities in the 1950s and 1960s), and the relatively high salinity of the inflow feeding the Sea has resulted in ever increasing salinity. By the 1960s it was apparent that the salinity of the Salton Sea was rising, jeopardizing some of the species in it. The Salton Sea has a salinity exceeding 4.0% w/v (saltier than seawater) and many species of fish can no longer survive. It is believed that once the salinity surpasses 4.4% w/v, only the tilapia will survive. Fertilizer runoffs combined with the increasing salinity have resulted in large algal blooms and elevated bacteria levels.[13]
Alternatives for "saving" the Salton Sea have been evaluated since 1955. Early concepts included costly "pipe in/pipe out" options, which would import lower salinity seawater from the Gulf of California or Pacific Ocean and export higher salinity Salton Sea water; evaporation ponds that would serve as a salt sink, and large dam structures that would partition the sea into a marine lake portion and a brine salt sink portion. Others advocate building a sea-level canal to the Salton Sea from the Gulf of California. Given that the Sea is over 200 feet (60m) below sea level, a sea level canal would allow thousands of tons of lower-salinity sea water to flow into the Sea without costly pumping or pipelines. Such a canal could be built large enough for recreational use and ocean-going vessels. A sea-level canal would promote dual purposes, as both an inland port for Southern California and a recreational/environmental asset along its course for humans and wildlife in Mexico and the U.S. A sea-level canal would also likely provide a way to regulate the shoreline of the Sea in a predictable manner.
Much of the current interest in the sea was sparked in the 1990s by the late Congressman Sonny Bono.[14] His widow, Mary Bono Mack, was elected to fill his seat and has continued interest in the Salton Sea, as has Representative Jerry Lewis of Redlands.[14] In 1998, the Sonny Bono Salton Sea Restoration Project was named for the politician.[14]
In the late 1990s, the Salton Sea Authority, a local joint powers agency, and the U.S. Bureau of Reclamation began efforts to evaluate and develop an alternative to save the Salton Sea. A draft Environmental Impact Report/Environmental Impact Statement, which did not specify a preferred alternative, was released for public review in 2000. Since that time, the Salton Sea Authority has developed a preferred concept[15] that involves the construction of a large dam that would impound water to create a marine sea in the northern and southern parts of the sea and along the western edge.[c
Criticisms of the preferred plan issued by the Salton Sea Authority include the risk of massive alkali storms blowing across the area destroying crops from the south basin.[16]
Many other concepts have been proposed,[17] including piping water from the Sea to a wetland in Mexico, Laguna Salada, as a means of salt export, and one by Aqua Genesis Ltd to bring in sea water from the Gulf of California, desalinate it at the Sea using available geothermal heat, and selling the water to pay for the plan. This concept would involve the construction of over 20 miles (30 km) of pipes and tunneling, and, with the increasing demand for water at the coastline, would provide an additional 1,000,000 acre feet (1.2 km3) of water to Southern California coastal cities each year.[18]
The California State Legislature, by legislation enacted in 2003 and 2004, directed the Secretary of the California Resources Agency to prepare a restoration plan for the Salton Sea ecosystem, and an accompanying Environmental Impact Report.[19] As part of this effort the Secretary for Resources has established an Advisory Committee to provide recommendations to assist in the preparation of the Ecosystem Restoration Plan, including consultation throughout all stages of the alternative selection. The California Department of Water Resources and California Department of Fish and Game are leading the effort to develop a preferred alternative for the restoration of the Salton Sea ecosystem and the protection of wildlife dependent on that ecosystem.
On January 24, 2008, the California Legislative Analyst's Office released a report titled "Restoring the Salton Sea."[19] The preferred alternative outlined in the draft plan calls for spending almost $9 billion over 25 years and proposes a smaller but more manageable Salton Sea. The amount of water available for use by humans and wildlife would be reduced by 60 percent from 365 square miles (945 square kilometers) to about 147 square miles (381 square kilometers). Fifty-two miles (84 km) of barrier and perimeter dikes – constructed most likely out of boulders, gravel, and stone columns – would be erected along with earthen berms to corral the water into a horseshoe shape along northern shoreline of the sea from San Felipe Creek on the west shore to Bombay Beach on the east shore. The central portion of the sea would be allowed to almost completely evaporate and would serve as a brine sink, while the southern portion of the sea would be constructed into a saline habitat complex. Construction on the project would be completed by 2035.
The documentary, Plagues & Pleasures on the Salton Sea, narrated by John Waters, covers the first 100 years of the Salton Sea along with the environmental issues and offbeat residents of the region.
A 6-minute short film, The Accidental Sea, filmed and narrated by Ransom Riggs, briefly discusses the history and depicts the desolation since the area's abandonment.[20]
The episode "Future Conditional" (#302) from the series Journey to Planet Earth (narrated by Matt Damon) talks about the plight of the sea, and, if nothing is done, a repeat of the fate of the Aral Sea will occur.[21]
The episode "Holiday Hell" (#206) from the series Life After People uses the Salton Sea as an example of how a resort town like Palm Springs would decay if no humans were there to maintain it.[22]
On March 24, 2009, a Los Angeles Times article reported a series of earthquakes in the Salton Sea. The article also quoted prominent geophysicists and seismologists who discuss the potential for these small quakes to spawn a massive earthquake on the San Andreas Fault.[23]
A film about some residents of the Bombay Beach community on the Salton Sea, Bombay Beach, was made in 2010 by Israeli-born filmmaker Alma Har’el, and described by The New York Times as a "surreal documentary".[24] The film won first prize in the feature documentary section of the Tribeca Film Festival in 2011.[25]
The Salton Sea and surrounding basin sits over the San Andreas Fault, San Jacinto Fault, Imperial Fault Zone, and a "stepover fault" shear zone system. American researchers determined that previous flooding episodes from the Colorado River have been linked to earthquakes along the San Andreas Fault. Sonar and other instruments were used to map the Salton Sea's underwater faults during the study. During the period when the basin was filled by Lake Cahuilla, a much larger inland sea, earthquakes higher than magnitude 7 occurred roughly every 180 years, the last one occurring within decades of the year 1700. Computer models suggest that the normal faults in the area are most vulnerable to deviatoric stress loading by the in-filling of water. Currently, a risk still exists for an earthquake of magnitude 7 or 8. Simulations also showed that in the Los Angeles area, shaking and thus damage would be more severe for a San Andreas earthquake that propagated along the fault from the south, rather than from the north. Such an earthquake also raises the risk for soil liquefaction in the Imperial Valley region.[26] The effective drainage divide that separates the Salton Sea from the Gulf of California is approximately 9 m (30 ft) in elevation and is located near Delta, northeastern Baja California State, Mexico, south-southeast of Mexicali.[27] Past sea level rise may partially be responsible for the salinity of the lake, while potential future changes in sea levels could occur. However, other factors such as hydrothermal vents, diffusion of salt from minerals and sediment, including concentrated brine and evaporites are another contributor to salinity, as is the recent lowering of lake levels raising the salinity, though sedimentary records show that the lake surface elevation reached levels 10–12 metres above sea level in the 1500s.[28]
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