In Where Does L.A. Water Come From? and A World of Water, Yet So Little To Drink we explored how rare fresh liquid water is despite the perception of vast abundance. In this post, we will focus on two types of water use in California – Blue Water (personal use and consumption) and Green Water (agricultural use for irrigation).

Los Angeles is the nation’s second largest city, yet consumes more water than any other U.S. urban region. The Los Angeles Department of Water and Power is the largest municipal utility in the country. As mentioned in an earlier post, the majority of water consumed in L.A. occurs in the residential sector – 68%. How do residents use all that water? If we look at indoor use, toilets (11%), clothes washers (8%), showers (7%), and faucets (6%) are the typical and predictable categories. But add these up and they yield just 35%. Outdoor use represents 65% of the residential sector’s total consumption: 49% for landscaping; 10% for other outdoor use (car washing, sidewalk cleaning, etc.); and 6% lost via leaks. Nearly half of all residential use goes toward landscaping! That’s amazing, especially considering that Los Angeles is a semi-arid grassland with a Mediterranean climate, receiving just 14 inches of rain each year with precipitation on just 35 days.

Indoor behavior modifications – taking shorter showers, installing low flow faucets, shower heads, and toilets, etc. – will make a difference, but the biggest hurdle will be changing outdoor behavior and preferences. In 2008, L.A. County’s population was 9.8 million; it’s been growing at a 3.6% annual rate since 2000. Adding new residents each year not only means more water consumers, it also adds attitudes and preferences for lawns and vegetation that are incompatible with the climate. Some see the region as a managed fantasy, utilizing exported water to create an idealized version of our preferred climate. It’s clear that changes are needed. Even modest adjustments to landscaping activity can be achieved without significantly diminishing lifestyle.

Green Gardens Group Los Angeles (G3LA) is a great resource for strategies, education, and training for what they call an ocean friendly landscape. They understand what works in the L.A. climate to mitigate water use. Check them out.

The other primary type of water use in California is agricultural irrigation, or green water. Agriculture is one of the state’s largest economic segments. At 17.6%, the state ranks first in the nation for dairy production, providing primarily butter and cheese. The state grows half of all U.S. fruits, nuts, and vegetables. All food requires water to be produced, called embodied water. Some of the thirstiest food types are beef, cheese, chicken, chocolate, nuts, olives, pork, and rice. According to a study by professor Arjen Y. Hoekstra for the Twente Water Centre at University of Twente in the Netherlands, beef requires 15,500 liters of water to produce 1kg of boneless meat. That’s 4,000 gallons for 2 pounds of beef. Think of that the next time you throw a few steaks on the back yard grill.

Most California farming occurs in the central valley. Historically, irrigation systems tapped into wells that tap into the Central Valley Aquifer, estimated to be the nation’s second largest in water volume. That aquifer recharges with runoff from the Sierra mountain range. Monthly readings have identified a troubling issue: the range’s estimated water content has been declining and may now have less than half the water of previous years. Industrialized agriculture practices were already withdrawing water from the aquifer at a rate faster than it can recharge through natural processes, but reduced mountain runoff means the aquifer is being drained at an accelerated rate. Four of the state’s five largest reservoirs are in an area with the most severe reduction in mountain snow pack. All five of the state’s largest reservoirs have water levels well below historical averages.

Limited supply throughout the state means that urban areas, such as Los Angeles, will now compete with farmers for the same water. It’s easy to be complacent and miss the interconnectedness of all these water issues, but nothing happens in isolation. Seemingly disconnected, small, inconsequential water use decisions made at our homes are now intimately linked to agriculture. Agriculture jobs are being lost due to failing farms. According to state statistics, unemployment rates in the central valley are highest – above 15% as of June. Failing farms put the U.S. food supply at risk. News of the California state budget crisis have been in the news for the past two months, but there’s bound to be more to come if we don’t look seriously at personal water use decisions.

This week, on July 21, 2009, the Los Angeles Council District 11 Empowerment Congress Environmental Committee held the Wise Water Use Expo in Mar Vista (Los Angeles). Kevin presented this material, and much more, with fellow presenters including Ed Begley Jr.

related posts:

• July 25, 2009 -- Wise Water Use Expo (4)
• July 16, 2009 -- a world of water, yet so little to drink (0)
• July 15, 2009 -- where does L.A. water come from? (1)
• April 13, 2010 -- 2010 Valley Water Expo (0)
• March 17, 2010 -- stories of sustainability: Black’s Farmwood (1)