By Sean Tubbs
Charlottesville Tomorrow
Sunday, July 18, 2010
Dry conditions have prompted the Virginia Department of Environmental
Quality (DEQ) to
declare a drought watch
for the entire state. However,
the Rivanna Water and Sewer Authority (RWSA) is not yet ready to
declare that the community’s urban water system at risk of becoming
depleted.
“Absent any rain over the next couple of weeks, I assume we will get to a
place where this community has a formal drought watch in place,” said
Gary O’Connell, the executive director of the
Albemarle County Service
Authority
.
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Under the terms of its
drought response and contingency plan
, the RWSA uses a computer model operated by the firm Hydrologics to determine the probability of a hydrologic drought. Current conditions of reservoirs and streams are compared with historical patterns and long-range weather forecasts to predict the drought potential.
According to the plan, a drought watch is to be declared by the RWSA if there is a 20% probability that the total capacity of the RWSA’s urban water system will drop below 80% within 12 weeks.
“Running the model today, [there is] only a 15% chance of reaching that figure in 12 weeks,” said Tamara Ambler, the RWSA’s watershed manager. “We’re still below the threshold.”
Ambler said the RWSA will continue running the model on a regular basis throughout the summer.
On Friday, the urban reservoirs were at 94.3% capacity. However, both long-range forecasts and water demand patterns have officials concerned that could begin to drop.
O’Connell said even with increased efforts by local government to encourage people to use less water in their homes, people tend to use more to lawns and other plants to keep them green.
“The average use has been going down, but as soon as we get into a dry weather period, it jumps back up,” O’Connell said.
According to RWSA data, the community used 12.5 million gallons of water on July 8, corresponding with a period where no rain fell in the community for ten days.
“On days of high heat, people do lots of outdoor watering,” O’Connell said. “As soon as it rained, it dropped back down to 10 million gallons.”
The statewide drought watch announced this week is designed to encourage citizens and localities to begin to reduce water in order to preserve water supply for as long as possible in case conditions stay dry.
Eighty-six percent of Virginia is experiencing abnormally dry conditions according to the U.S. Drought Monitor, a consortium of federal agencies and universities.
“What we’re doing with this drought watch declaration is to encourage all localities to take the appropriate steps to conserve water,” said Bill Hayden, a spokesman for the DEQ. “The conditions are there where we can have a drought really quickly.”
Under a drought watch, ACSA customers and Charlottesville water users would be asked to voluntarily restrict usage by only watering outdoor plants and lawns at night.
The ACSA and the Charlottesville utilities division will begin running a series of advertisements to encourage people to resist the temptation to keep their plants green.
“We’re saying people let their lawns go dormant rather than water them because they’ll come back when the rains return,” said Lauren Hildebrand, the city’s director of utilities. She added the city and the ACSA also encourage citizens to plant drought-tolerant vegetation.
A drought warning is declared if there is a 10% probability that total useable storage will drop to 70% of capacity within 10 weeks. A drought emergency would be called if there is a 5% or greater possibility that useable capacity drops to 60% of storage.
Legally-mandated restrictions can only be enacted by the Albemarle County Board of Supervisors and the Charlottesville City Council following the RWSA’s declaration of a drought warning.
