Category: Water Facts

How Effective is L.A.’s Conserving Water by the Glass?

Published / by dcoffin / Leave a Comment

City of Los Angeles Emergency Water Conservation Order regulations prohibit restaurants and other public places from serving water to customers unless they specifically ask for a glass of water. So how much of a reduction of water does this city ordinance make and does it have any practical effect on reducing L.A.'s demand?

waterglassWe'll set up an admittedly unlikely scenario where every person 15 years and older in the City of Los Angeles goes out to eat in a 'sit-down restaurant' every other week and has a 16 ounce glass of water served to them.  The 2010 US Census tells us there are 2,956,181 people in the city that fall into that age group.

The size of the average glass is probably on the big side, the number of patrons and frequency of eating out is probably a bit high side, but over estimating the demand created by serving water is better than downplaying it for the purpose of this article. 

Under this scenario, restaurants would serve about 9.6 million gallons a year. A little more if we add washing the glasses but again, it's highly unlikely L.A. City restaurants with 'waited' tables are seeing 77 million patrons a year.

While 9.6 million gallons sounds like a lot, in the larger picture it's just 29 Af/y in a city whose historical demand is over 620,000 Af/y or 202 billion gallons. I'll set aside the meaningless Olympic size swimming pool comparisons that are often made in the media to describe water volume and instead describe what the reduction means in a more practical way:

  • 29 Af/y is roughly the amount of water 325 people would use over a period of one year in a city of 4 million.
  • 29 Af/y would provide only 9 percent of the 1,444 unit SOLA project projects demand that the LADWP recently recommended for approval.
  • 29 Af/y is enough to support only about 89 average single family residential units for one year in a city with over 627,300 units.
  • 29 Af/y is enough to support only about 140 average multi-family residential units for one year in a city with over 764,400 units.

So how much is saved? None really. The restriction on serving water to restaurant patrons has no practical effect on reducing demand in a city whose demand continues to grow on a daily basis. The restriction hasn't helped reduce the city's deficit since it was imposed in 2007. In fact, the deficit has deepened in spite of it. This restriction in the city ordinance is merely a legal reminder that the city has been operating under a water deficit for the last eight years.

Another Look at Where L.A.’s Water Goes

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In another earlier post we saw 'how much' water each consumer group in the City of Los Angeles used. Here is a comparative look at where the water goes by percentage. LACity 2014 Group Next we see both where the growth or reductions in share are between 1984 and 2014.
ResShare CityGovShare
IndShare ComShare
Residential share increased from 60.9% to 68% (12 percent change). Commercial was relatively flat at .3 percent from 17.4% to 17.7%. Industrial share fell from 4.7% to 3.3% (30 percent loss) of total supply while City Government increased from 6.2% to 7.2% (16 percent change) of total supply.

Promise of Backup Water Not Met by DWP

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Construction projects going through the city permit process are required to cite how much water demand they will impose on the city's water supply and whether the city has surplus water supplies to accommodate the project.

2010
2010 UWMP states that MWD would make up for city shortfalls.

This information is provided in the EIR (Environmental Impact Report) which is part of the permit package for the project. The EIR's have a section on 'Utilities' stating where this surplus water will come from. As evidence of sufficient surplus water, the EIR's refer you to the city's current UWMP as evidence. The UWMP also describes how it will meet demand should there be a shortages of city owned water. When water shortages occur the city's water plans state that they have access to MWD supplies that will meet the city's level of demand.

The chart below shows us that despite the UWMP's guarantee that the Metropolitan Water District will be able to provide sufficient water supply in dry years, the DWP has not been able to meet that guarantee since MWD supplies have come up short of the projections every year since 1990.

The deficit the city finds itself in is a result of this gap. Because this has been allowed to occur for twenty five years and never corrected in each subsequent UWMP,  we have to assume that these statements in the UWMP assuring that MWD will meet demand are mainly intended to facilitate approvals and nothing more. As such, it is a planned deficit.

MWD supplies have not been sufficient to meet the city's demands.
MWD supplies DWP water during shortages but has not been enough to meet the city's demands.

Would ‘Lose the Lawn’ Solve L.A.’s Water Problem?

Published / by dcoffin / 1 Comment on Would ‘Lose the Lawn’ Solve L.A.’s Water Problem?

Would "Lose the Lawn" solve the City of Los Angeles's water problem? Throughout the state the crescendo to eliminate residential lawns has grown louder among water boards, agencies and political leaders.  In Los Angeles, a partnership between the Metropolitan Water District and the DWP will even pay residents $3.75 per square foot to convert their lawns 'drought tolerant' landscape with arguable curb appeal.

"Californians should water enough to save their trees, but should let their lawns go the way of all mortal things."

Felicia Marcus - Chairwoman Water Board

So given the following extreme example, how much water could the city save if every single family home throughout the city participated in the program and killed off their lawns? And what would the long term benefit be to residents?

According to the LADWP, the 627,395 single-family residential homes it serves used an average of 144.88 HFC (hundred cubic feet) of water during the 2013/2014 water year. The same year 764,402 multi-family residential homes used an average of 96.42 HFC.

In our example we'll ignore other patterns of usage between the two types of homes (residents per household, etc.) and simply assume that the difference is entirely landscape and cut the single family home demand to 96.42 HFC just like multi-family households.

By 'Losing the Lawn' we find the city would at most reduce water demand by 69,805 Af/y or 12%. The actual reduced demand would most likely be much lower.

Benefits are only temporary

Outside of finding a way through this statewide drought there is no real long term benefit from turf removal for the residents of the City of Los Angeles.

losethelawn2aThe main beneficiary of the reduced demand would be the Metropolitan Water District since the city would be buying less water from the agency each year. If the MWD could store this water and build up reserves that would be a good thing for all. However it will most likely will be a combination of storing some of the water and selling the rest to its other member agencies.

As for the city and it's residents, L.A.'s continued growth enabled by the departments heavy reliance on paper water would quickly wipe out all of the savings within ten years. The city's 2010 UWMP projects the demand will increase by 60,000 Af/y in 2025 and by 86,000 Af/y in 2030. Nearly all of this increase will be multi-family residential so effectively residents would be trading their homes lawn for density.

Since we can expect that the city's real water supply will remain flat, growth will assure that the city's future supply would be as tedious after the lawns are gone as they are today.

Where L.A.’s Water Goes

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Where does the city's water go? This chart shows us how much water is used in each of the city's consumer classes between 1985 and 2014*. Since 2007 single-family residential demand has fallen from 261,530 Af to 208,678 Af. Multi-family residential has fallen from 187,059 to 169,192.  More importantly, Residential per capita has fallen from 106 gallons per capita daily to 86. Where L.A.'s Water Goes *Supply shown in 'water years' (October thru September).

Paper Water is No Small Change

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The City of Los Angeles water plans in the past have projected significant amounts of water that later never came. These large sums of water have been used to approve small and large projects going back to 1990.

When projects are reviewed by city planners, the figures cited in the city's water plans are supposed to assure the community that there is sufficient water for the project over the next 20 to 25 years after they are approved and that the project will not pose a burden to the city's water supply during that period.

LAfacade628

Over a 24 year period, this missing water would be equivalent to 4.35 million acre feet which is slightly more than a full years worth of California Aqueduct water at full allocation.