Wednesday, August 3, 2016

Droughtful Musings on the LA Basin: Desert, or No?


There's a raging conversation going on at the Facebook California Native Plant Society page: a furor over a LA Times article Will replacing thirsty lawns with drought-tolerant plants make L.A. hotter?

People are tearing up lawns at an unprecedented rate, and the speculation is that using native plants will make LA hotter, and more arid than it already is. I considered it seriously slovenly journalism. Teacup tempestuousness. Not enough news, today?
  
The solution seems simple: plant more street trees.
Plant native oaks and sycamores. Focus on native plants instead of exotic plants and lawns.

Native plants are not the problem...it's the sheer square mileage of pavements grey that's the real problem in LA—mind-boggling square mileage of endless freeways and surface streets, shopping mall parking lot of black asphalt, and don't forget all those tarred roofs. sidewalks, bricks, patio pavers. Those stupid lava rocks and Astroturf people use to replace their lawns are not helping the problem. White reflect heat, black absorbs. There's a reason why Greek villages are painted white.

This is the crux of the article i
n a nutshell:
...what would happen to the city’s overall temperature during the month of July if every lawn were replaced with drought-tolerant plants.... a lawn-less Los Angeles would be up to 3.4 degrees warmer during the day than it is now....
But the scientists also discovered that
transforming lawns to drought-tolerant vegetation has an average nighttime cooling effect of about 5.4 degrees that more than makes up for the daytime warming....
There's concern that the
average summertime temperature be affected if all the city’s vegetation — lawns and trees — were ripped out and replaced with drought-tolerant shrubs.
What they discovered was that
the average daytime air temperatures actually dropped by 0.4 degrees. That’s because, with no trees in Los Angeles, sea breezes would blow through the region unhindered by tree trunks, counteracting the warming you’d expect from the lack of irrigation.... Plants and trees provide shade and transpire moisture to cool the air; gravel and artificial turf don't. ...when it comes to the climate in Los Angeles, nothing is ever simple. Will replacing thirsty lawns with drought-tolerant plants make L.A. hotter?

CNPS member Thomas Yeary is an advocate for repopulating the LA Basin with California native plant species endemic to the area: "Coastal and Alluvial Sage Scrub, Chaparral, Oak Woodland, Gallery Forests, Riparian Corridors, Coastal Prairies, Yellow Pine forest, Southern California Walnut woodlands, Dune scrub, Salt and Fresh water marsh all historically have naturally occurred in the Los Angeles area."

He speculated that 
up to 90% or more of this natural landscape has been modified and in most cases completely removed leaving most species of plants and animals extirpated. This and the disruption of the natural processes of material deposition by creating flood control networks, dams, hardscapes, buildings and storm channels are the real underlying issues that should be addressed here. Non-site specific native vegetation, long term will never work and that's the truth.
Another CNPS member, of the lawn persuasion, said that lawns transpirate and don't reflect the sun so on a hot day so a lawn  is cooler than bare ground.  I like walking barefoot on lawns, but lawns are, for the most part, an abomination in California, where it doesn't rain in summer. It's an east coast thing.

Andrew Glazier said: "I tore my lawn out almost a decade ago. I have more birds in my yard than my birder friends can count. I have butterflies like mad each year. native bees give me loads of fruits and vegetables.... I tear out lawns and plant natives for a living and I can't keep up with demand. I lived in L.A. for many years. I now know the mere existence of water in these great quantities has already been an environmental crime and part of a real estate windfall. L.A. was a desert before."

Thomas Yeary queried the assumption that LA was a vast desert: "When was Los Angeles a desert?" 

Another member chimed in and said that LA is a Mediterranean climate with fickle winter rainfall and no summer rainfall. About half of all years (?) are as dry as a desert but some years are very wet.
  
All this talk about the weather got me to Googling my own assumptions. The LA Basin is Mediterranean, not a desert? I thought: no way! By the time I got done Googling, I did an about face with my own assumptions. Los Angeles Is Not a Desert. Stop Calling It One.

I guess I've always defined LA as desert, because for over two centuries they've exceeded their water supplies—destroying Owens Lake, and Mono Lake in the process of stealing water from the back side of the Sierras. I worked on the Save Mono Lake campaign—with Barbara Boxer. I also live in northern California, where some years, we get so much rain, we could almost join rain forest status. Everything's relative.

The LA Basin may be Mediterranean, and if weather and rainfall are averaged out, then it is Mediterranean. But it is also facing the worst drought in 1,200 years. Maybe we need to define what the process of desertification is. The basin has never traditionally supported a large population because water was not plentiful. 

I was surprised to find there were mountain-fed wetlands in the LA Basin. Imagine marshes south of Wilshire Boulevard, and streams flowing from the Hollywood Hills. Apparently one stream still flows across Wilshire Country Club to Hancock Park. The rancho where Beverly Hills sits, was called Rodeo de las Aguas or the "gathering of the waters." And who knew that La Cienega means springs. But there were also wetlands in Las Vegas too. So what defines a place as Mediterranean?

The LA Basin, a vast alluvial plain, has a Mediterranean climate with winter rains (averaging 12-15" year—much higher in the mountains) with warm summers. Butt much of LA also has desert conditions with extremes—either a profound lack of water, or a deluge with flash floods. The LA River and most groundwater disappeared by 1903; pop. was 100,000.

Still unwilling to let go of the idea that LA isn't a desert, I looked at average rainfall, since water—or a lack of it—seems to be at the crux of the CNPS thread. I discovered that there were quite a few years of little rain—less than 10 inches. Some definitions of desert include an average rainfall of 10" or less—with an average of 7 inches; but some deserts receive 12+ inches a year—The Mojave receives more rainfall than most deserts. So, apparently there's no hard and fast rule. 


That's 27 cumulative  years of little rain (only 10 deluge years 20-30") in the past 70 years. Not quite half of all years but 3/7ths of the time LA, with its lack of rainfall qualifies as desert.

2015-2016 - (56% of normal)
2014-2015 - 8.52"
2013-2014 - 6.08"
2012-2013 - 8.69
2008-2009 - 9.08
2006-2007 - 3.21
2003-2004 - 9.25
2001-2002 - 4.42
1998-1999 - 9.09
1993-1994 - 8.11
1989-1990 - 7.35
1988-1989 - 8.08
1986-1987 - 7.66
1980-1981 - 8.96
1975-1976 - 7.21
1971-1972 - 7.17
1969-1970 - 7.74
1963-1964 - 7.93
1962-1963 - 8.38
1960-1961 - 4.85
1959-1960 - 8.18
1958-1959 - 5.58
1956-1957 - 9.54
1952-1953 - 9.46
1950-1951 - 8.21
1948-1949 - 7.99
1947-1948 - 7.22

http://www.laalmanac.com/weather/we13.htm

IN 1500, about 25 Tongva villages exist in what is now Los Angeles County. Population: 300 to 500. Population didn't increase when the padres founded San Gabriel Mission, the pueblo, etc. Even statehood didn't affect it. The pueblo of old Los Angeles, remained small until the completion of the Santa Fe Railroad 1885. By 1903, the population exploded to 100,000. They sucked the LA River dry. Enter Mulholland, with a dream of water.


Glendora resident,  Thomas Yeary wrote that: "Los Angeles receives plenty of water suited for the natural vegetation, climate and geological processes that take place here. In our San Gabriel Mountains we receive on average between 25-and 50 inches of rainfall annually with El Niño years pushing us up to an average of 70 inches. Snow will usually fall above 4,000 feet elevation between October and April, with most of it coming December through March. There are countless natural springs and water sources in the mountains. Coastal Fog creeps in nightly through the basin into the valleys. We receive summer thunder showers as well. Quite a bit of water compared to the surrounding deserts. Just not at the flick of the switch all year round like so so many :( currently demand it."

LA's water came at a great cost to Eastern Sierra lakes; most are gone, some a re mere puddles of themselves

Most people seem to agree that Southern California is an arid place, and that high water use on plants raises humidity, and creates changes to environments. Certainly taking away all the available groundwater and pumping it to LA Basin has had a huge negative impact on the entire Eastern Sierras. When the wind blows, the region is laden with toxic alkali dust.



For example, Owens Lake, once a vast inland freshwater sea, with an average depth of 250 ft., is now a dry playa with a shallow alkali puddle in the middle. To give you an idea how big it was, Highways 395. 136, and 190 skirt the former shores of Owens Lake. You can see how vast the lake was if you go up Whitney Portal Road. Watch Chinatown too, it covers the LA Water Wars.Andrew Glazier said: "L.A. residents and all folks who care need to drive the Owens valley to Mono Lake once in their lifetime to see where the water running down the gutters comes from. Please do this. You will not regret it."


Owens Lake from Whitney Portal Road. Alabama Hills to the left. 
Road leads to Lone Pine. The White Mountains in the distance.




"William Mulholland, superintendent of the Los Angeles Department of Water and Power (LADWP) planned the 223-mile (359 km) Los Angeles Aqueduct, completed in 1913, which diverted water from the Owens River. The water rights were acquired in a deceitful manner.... Los Angeles acquired a large portion of the water rights to over 300,000 acres (121,000 ha) of land in the valley, almost completely diverting the inflows of water away from Owens Lake....  —Wiki

Alkali storm, Mono Lake. Most of the Eastern Sierra lakes were destroyed by LA Water
"In 1970, LADWP completed a second aqueduct from Owens Valley. More surface water was diverted and groundwater was pumped to feed the aqueduct. Owens Valley springs and seeps dried and disappeared, and groundwater-dependent vegetation began to die. Years of litigation followed. In 1997, Inyo County, Los Angeles, the Owens Valley Committee, the Sierra Club, and other concerned parties signed a Memorandum of Understanding that specified terms by which the lower Owens River would be re-watered by June 2003."  Wiki
 
Yeah. Didn't happen.
The
Owens River, or the LA River have not been re-watered. When it comes to water, LA is thirsty as a desert. C'mon, LA, pull up those lawns, plant some native species. It's the right thing to do.






   
SOME INTERESTING LINKS

Climate of Los Angeles The weather in LA may be Mediterranean, but one record high was 92° in January, xxxx year  with a record low at 28°; and another record-breaker was 113° in September. what? XXX year.

Los Angeles County Almanac Total Seasonal Rainfall (Precipitation) Los Angeles Civic Center, 1877-2015. Average since 1877 thru 2015 (138 years): 14.81 inches

Los Angeles Is Not a Desert. Stop Calling It One.

Los Angeles is not a desert  There's a movement to ask LA Times writers to stop referring to Los Angeles as a desert, climate-wise—it's a the desert canard dating back to the 1880s. Historian Ralph Shaffer says it rains too much for the coastal plain to qualify as a desert. Wilshire Boulevard once had marshes that lay south of the road -- streams once flowed from the Hollywood Hills. One still flows across the Wilshire Country Club through Hancock Park. The rancho where Beverly Hills sits, was called Rodeo de las Aguas — "gathering of the waters.")

Los Angeles Aqueduct  The History Channel

Cadillac Desert - 1. Mulhollands Dream (1 of 9)

Owens Lake Project

Owens Valley



I explore delta water links a bit more indepth here:California water wars: It's not about the fish, Stupid.

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