As a California resident, I am bombarded by drought alerts and pressure to conserve water. The California Department of Water Resources is warning us that 2010 could mark the 4^th consecutive year of drought. Even though the state suffers from a $20 billion budget deficit and carries over $70 billion in outstanding bond debt, the senate has put an $11.14 billion water bond measure on the November ballot –there is a strong sense of urgency in the state regarding our future water supplies.

While planning my summer vacation in Japan I asked myself a question: Does Japan suffer from domestic water shortages like California does, and why? It seems proper to compare California and Japan. Both have huge economies: California’s economy is the eighth largest in the world while Japan’s is the third largest in the world. The majority of Californians and Japanese rely on public water sources for domestic supply.

The two places are vastly different in ways that make comparison interesting. While both entities occupy nearly the same land area (California: 403,932 km², Japan: 394,743 km²), Japan’s population is over three times the size of California’s (California: 38.3 million, Japan: 128 million). The Tokyo prefecture alone touts a population of nearly 39 million while occupying an area equivalent to 10% of California’s area.

California has water supply problems primarily because 75% of its water originates in the top third of the state while 80% of demand is in the southern two thirds of the state. To sustain large populations in southern California, the state and federal government constructed dams and canals to boost water storage and transport. California has a storage capacity of nearly 50 billion cubic meters spread over 1000 dams. Japan is abundant in water resources; the country consistently receives one to two meters of rainfall each year. The country’s abundance of water has made it easy for people to obtain water without massive dams and canals. Japan sports a distributed network of over 2500 dams that have a total storage capacity of about 20 billion cubic meters –less than half the capacity of California’s dams.

Demand for water in Japan is also far lower than in California. California’s domestic water use is about 470 liters per capita per day (2005 USGS data). Japan’s domestic water use is one-third less at 314 liters per capita per day (2008 data). Why is the demand so different? One explanation is that city dwellers in Japan rarely need water for outdoor irrigation. Drive through the streets of a Southern California suburb and you will see lot after lot of lush front lawns (don’t forget the back lawn too!), flower gardens, and trees. The California Homebuilding Foundation estimates that over 50% of water demand in California homes goes towards outdoor landscaping. Outdoor use is less in Japan where population densities are often several times higher than even the densest California cities –there is no room for a lawn.

Japan devotes nearly twice the fraction of its water to industrial purposes as California does. Meanwhile, California invests more water into agriculture.

Note: Japan might suffer from water shortages if it were forced to produce its food and other water-intensive materials domestically. Currently Japan is less than 45% food self-sufficient so it indirectly consumes the water used to produce grains, oils, and meats its people import. Japan is also one of the world’s top textile importers. Global water shortages would affect food and textile production which would in turn affect Japan’s ability to feed and clothe itself. Not even the water-abundant Japan can escape the effects of global water shortages.

The Public Policy Institute of California estimates that California’s population will grow to 46.7 million by 2025. Current water supplies can barely satisfy the demands of today’s 38 million residents. A 23% increase in population will further stress the water situation in the state.

Meanwhile, Japan is predicted to experience a population decrease of 20 million people over the next 50 years. The country does not expect to have water shortages in the near future: Japan’s growth is not limited by its water supply.

Water supply currently limits growth in California. A cap on growth is not inherently bad, though. One can argue that investing billions in expanding water supplies will enable new growth, but further growth will encourage further billions to be invested in expanding water supplies. This creates a positive feedback loop that is difficult to escape: Growth fuels demand, new supply fuels growth. The nearly bankrupt state cannot sustain this cycle forever.

Like Japan, California’s population will peak. Unlike Japan, this peak will most likely be a result of water shortages. Japan is able to sustain a large population because its water resource is abundant and because its per capita demand for water is relatively low. California’s water supply is scarce and its demand high.

How do you think California can solve its water needs in the long term? What do you think about the new water bond on the November ballot? Feel free to comment.

Posted in Water Resources | 2 Comments »

2 Responses to “State of Water: Comparing California and Japan”

1. Amy says:

   June 30, 2010 at 6:39 pm

   Culturally, Californians and Japanese people might have different outlooks on saving water. Instinctively I believe that the Japanese are far more conservative when it comes to domestic water usage than, say, the Northern Californians. I say that because I have lived in both places and these different groups of people have different habits.

   California is also the number one producer of crops in the US, and agriculture of that scale requires a ton of irrigation.

   As with the water used to irrigate front and back lawns, perhaps one day biological engineers would be able to tweak beautiful non-native plants (especially green grass) to survive at low water levels.

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2. Nick Lee says:

   July 1, 2010 at 11:10 am

   The attitude towards natural resources is definitely different in both places. Japan is scarce in many of the resources that fuel the modern economy (i.e. coal, natural gas, and crude oil) so they must import them at high cost. Before Commodore Perry arrived in the mid 1850s, people in Japan had already spent over two millenia growing and developing without the energy-intensive processes that fueled growth in the United States.

   Meanwhile California became part of the United States in 1850, long after the industrial revolution had transformed the East Coast. California had been settled by Americans with a desire to explore and tame the West. Expansion and growth became part of California culture. Today this is changing. Water and fuel shortages are making Californians rethink the way they live.

   California’s status as the #1 crop grower in the United States is threatened by the decline of the San Joaquin Delta. If the delta’s levees collapse, California will not only be short on food crops –it will be short on water for its citizens to drink. I encourage you to read about the 2010 Water Bond on this November’s ballot. See what you think about it, and register to vote!

   The idea about bioengineered grass is interesting, but there are other policy roadblocks that we can overcome to solve irrigation problems without the need for genetic engineering. Many California grasses are drought resistant. They will survive drought –they will just look ugly while doing it. In order to get lush green lawns, grass simply needs a lot of water. Even if I as a homeowner do not care for green grass, I can get fined by my city for not watering my grass (it lowers the property value of your neighbors).

   Article about how a woman was arrested for not watering her lawn: http://www.ksl.com/index.php?nid=148&sid=1444771

   Reply