Department of Water Resources
A daily compilation of significant news articles and comment
May 5, 2009
5. Agencies, Programs, People –
'New Era' in Water Means Brown Lawns
The Voice of
Waves of the future
The
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'New Era' in Water Means Brown Lawns
The Voice of San Diego
By Rob Davis
Coming this summer to an inland neighborhood near you: Brown lawns.
Mayor Jerry Sanders unveiled a plan Monday to designate specific lawn watering days for all residents and businesses, a step one horticulture expert said would "absolutely" cause brown and dying lawns across the city this summer. The risk would be higher farther inland.
Sanders' plan would allow residents in odd-numbered houses to water their lawns on Sundays, Tuesdays and Wednesdays. Even-numbered houses would be permitted to irrigate Mondays, Wednesdays and Saturdays. Businesses, condos, apartments and homeowners associations would be allowed to water on Mondays, Wednesdays and Fridays.
"Today, we're poised at the beginning of a new era in
The plan heads to City Council for consideration and possible approval Tuesday afternoon. It comes as the city faces mandatory water cuts from its suppliers for the first time since the early 1990s.
If approved, regulations would begin June 1 permitting residents to water for 10 minutes on each specified day and only between the hours of 6 p.m. and 10 a.m., when less water is lost to evaporation.
That won't be enough to keep many lawns green, said Don Schultz, an instructor in the ornamental horticulture department at
"To apply half of what I'd consider the optimal water probably wouldn't keep it green," Schultz said.
The city of
The 10-minute, three-times-weekly baseline was recommended by the San Diego County Water Authority to water districts across the county. John Liarakos, an authority spokesman, said three 10-minute cycles weekly should be enough to keep lawns green.
"If it's done properly, if they're doing it after dark, before early morning, it should be adequate," Liarakos said.
Under the proposal, the city's Water Department would spend $750,000 to hire 10 code enforcement staff -- water cops -- to investigate complaints of waste and ensure compliance. It will rely on neighbors to report waste. Alex Ruiz, the department's assistant director, said the city would take a "progressive approach" to enforcement. While it could fine residents between $100 and $1,000 for violating the lawn-watering rules, the city will give residents at least two warnings before fining them.
Residents with efficient irrigation systems, such as drip irrigation, would be exempt. So would golf courses' greens and tees.
The county water authority is restricting deliveries to
City Councilwoman Donna Frye, who joined Sanders at a Monday press conference, said she believed city residents would respond. "I have a lot of faith in the public," she said. "I believe they'll actually take this to heart."
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Sanders had pushed earlier this year for a plan that would've established water budgets for each household based on their historical consumption -- a plan criticized for its lack of fairness.
The city has turned away from that plan as the year's water-supply picture has improved. Sanders said the city now has time to evaluate other options.
"This gives us an opportunity to review what we did, what's out there," Sanders said. "This is a great time to look at all the alternatives as we move forward."
The city's current plan has no guarantee of success. The state Department of Water Resources warned in a 2008 report that designated lawn-watering days don't always work. "Some residents water on the designated days regardless of whether the landscape needs it," the report states. "Others over irrigate their landscapes in the hope the irrigation will last longer. This overuse cannot be controlled by patrols."
The report also cautions that confining lawn watering to nighttime hours, when residents are sleeping, can allow sprinkler malfunctions to go unnoticed.
http://www.voiceofsandiego.org/articles/2009/05/05/environment/847wateringdays050409.txt
Waves of the future
The San Diego
By Scott LaFee
Just minutes after the seafloor north of the Indonesian island of Sumatra buckled on Dec. 26, 2004 – the result of a 9.3-magnitude earthquake, the second strongest ever recorded by a seismograph – analysts in Alaska and elsewhere knew a massive tsunami would likely follow.
Warnings were immediately issued. Phone calls were made. But the effort was too little, too late. The quake happened early on a Sunday morning. Most government offices were closed. Word was appallingly slow to reach small, isolated villages along the coasts of
When the first tsunami waves hit land 40 minutes after the quake, whole communities on the Sumatran coast disappeared beneath successive towering walls of seawater, each quickly clogged with debris and bodies. The tsunami spread, striking the Thai resort town of
And yet, few alarms sounded. In the end, more than 225,000 people in 11 countries died, with millions more displaced. Economic damage exceeded $10 billion, a huge amount in this mostly impoverished region.
The rest of the world watched in anguished awe, realizing that what happened in the
If a tsunami were to strike today, however, chances are much better that people in imperiled areas could be warned in time. Major elements of a global tsunami early warning system have been put in place, though some regions of the world remain uncovered.
In early 2005, the Bush administration announced a $37.5 million program to build an expanded, second-generation tsunami warning system called Deep-Ocean Assessment and Reporting, or DART2.
Closer to home, Science Applications International Corp. (SAIC), a multibillon-dollar technology company and defense contractor based in
“After the 2004 tsunami, a lot of countries began to seriously look at early warning systems,” said Robert Lawson, vice president of ocean and atmospheric programs at SAIC. “Only NOAA had any real experience, and it was not set up to provide buoys to the rest of the world. This was something we thought we could do.”
Working closely with NOAA engineers, SAIC developed its own prototype buoy in 2006, testing it for four months in deep water 200 miles west of
Early this year, SAIC officials dispatched two completed buoys to
Last year, NOAA deployed the final two buoys of its DART2 system – a network of 39 buoys that now stretches across portions of the Pacific and Atlantic oceans, the Caribbean sea and the
“Completing the U.S. Tsunami Warning System is truly a monumental triumph,” said retired Navy Vice Admiral and former NOAA administrator Conrad Lautenbacher. “As a young scientist who researched tsunamis and built early models of their effects, I never imagined that we could come so far in our ability to understand, to detect, to model and to warn on such a scale as we have just achieved.”
Undersea eyes
Both the SAIC and the DART2 buoys employ the same basic technologies and principles. Each device consists of two basic components.
The first is a bottom pressure recorder, an electronic device that measures water-pressure changes as ocean waves pass by. It is extremely sensitive, capable of detecting minute pressure alterations, but also able to filter out routine fluctuations caused by tides and currents.
The recorder, encased in a waterproof compartment, is attached (along with supporting batteries and other electronic components) to a heavy metal platform that anchors it to the seafloor.
Lawson said the recorders work best in deep water, preferably between 6,000 and 19,000 feet.
The second component is the buoy, which in the SAIC version is a highly visible yellow cylinder 7 feet in diameter and 13 feet tall. The buoy is tethered to a couple of surplus railroad car wheels weighing a combined 7,200 pounds. These anchor-wheels are deposited not far from the bottom pressure recorder.
Bobbing on the ocean surface, the buoy serves as a communications relay station. When the bottom pressure recorder detects a notable change in water pressure, it sends that information to the buoy, where onboard electronics relay the data to a satellite that in turn transmits it to a warning center in either
Lawson declined to reveal how much the buoys cost, saying only that the price was well under $1 million each.
The buoys are typically located in seismically active regions where undersea earthquakes may generate dangerous tsunamis. At greatest risk are coastal countries encircling the Pacific Ocean's “ring of fire,” a 25,000-mile horseshoe-shaped belt riven with fault lines and dotted by more than 75 percent of the world's active and dormant volcanoes.
The U.S. West Coast lies on the western arm of the ring, making it potentially vulnerable to tsunamis. A 2005 study by the U.S. Geological Survey identified two places where colliding tectonic plates could cause a major tsunami affecting the
In 1964, a 9.2-magnitude quake occurred on the Prince William Sound fault, generating a tsunami that swept all of the way down to
While
And any significant tsunami could be disastrous. A 2005
Rough waters
Installing a tsunami warning system is one thing; keeping it functional is another.
“The ocean is a tough place to keep sensitive electronic gear working,” said Lawson.
Generally speaking, the buoys must be rotated and refitted once a year, the bottom pressure recorder array every two years. Engineers retrieve the pressure recorder by transmitting a signal for the device to release itself from the heavy anchor plate. Attached floats then pull the recorder to the surface.
Lawson said the biggest maintenance headache is biofouling. The buoys provide a welcome home for clinging barnacles, worms, plants and other sea life.
“This stuff doesn't really affect the buoy's functioning,” said Lawson, “but after a while, all of that accumulating growth starts to pull down on the buoy and make it unstable.”
Lawson said the buoys also occasionally suffer damage from local fishermen. “The mooring lines beneath the buoys tend to attract fish, which the fishermen know,” he said. “So they'll hook onto a buoy and pull it back, stringing a net where the buoy had been. Then they release the buoy, which snaps back into position, driving the fish into the net. Obviously, this isn't good for the mooring system.”
Buoys have also been snagged and dragged by trawlers' nets, damaging the buoys and, in the case of an Indonesian buoy in 2007, actually severing a jacketed steel wire mooring line.
Pirates are a problem, too: “In that part of the world, unfortunately, if someone sees a buoy loaded with electronics and batteries just floating there, they're probably going to take and sell parts of it,” Lawson said.
As soon as multiple buoys begin reporting anomalous water pressure changes and indicating wave direction, scientists can start to determine if a tsunami is coming – and if so, how bad it might be.
“Combined with all of the seismic sensors in the ocean and other data sources, not to mention newer and better computer models, scientists have gotten pretty good at assessing tsunami threats,” said Lawson.
“From the time a buoy detects something to the time that information arrives at the warning center is usually less than five minutes from any ocean. Then it takes maybe 10 more minutes to process the data, come up with a determination of threat and send out a response.”
That response may be a warning to any at-risk country that a tsunami is heading its way. Conversely, it may be an all-clear, a message that there is no significant danger. That is important, too. In 2003, NOAA scientists determined that a potentially catastrophic tsunami was not, in fact, a threat to
However, it is the real danger of real tsunamis that drives people like Lawson. Expanding buoy warning systems will help prevent future catastrophes, but Lawson said it was also critical that at-risk countries build reliable communications systems to make sure warnings are heard and effective evacuation programs are run by trained professionals who know what to do.
That requires not just wealth, but political and social will.
“It can be decades between really big tsunamis,” Lawson said. “You can't just build systems and then forget about them.” #
http://www3.signonsandiego.com/stories/2009/may/04/1c04tsunami191915/?science&zIndex=93230
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