By Brian Wheeler
Tuesday, July 12, 2011
Changes in population assumptions and a 20 percent drop in per capita water use are two of the main factors driving down the projected water needs of the Crozet community in western Albemarle County.
The Rivanna Water & Sewer Authority is holding a series of public meetings this week to discuss water demand forecasts for the Charlottesville-Albemarle area. The analysis projects the community’s water needs in the year 2060 for the urban area and separately for the communities of Scottsville and Crozet.
Download AECOM's July 5, 2011 draft forecast
| Kim Shorter, AECOM Technology Corporation
Crozet’s water needs were the focus of the first meeting, held Monday evening at Western Albemarle High School where the draft forecasts commissioned by the RWSA were presented to a handful of local residents.
Kim Shorter, a water supply specialist with AECOM Technology Corporation, said population estimates were a big driver of any water forecast.
“We are using very current population and employment numbers based upon the updated Crozet Master Plan,” said Shorter in an interview. “The Albemarle Community Development staff told us to assume an 80 percent build-out would be achieved in Crozet by 2060.”
Crozet is on a separate water supply from the urban area around Charlottesville, thus planning for its long-term needs have largely been a separate matter from the debate over the new earthen dam at the Ragged Mountain Reservoir, planned as part of the almost $140 million water plan being implemented by the RWSA.
In June 2007, engineering firm Gannett Fleming examined the so-called “safe yield” of the Beaver Creek Reservoir and determined it could provide 1.8 million gallons per day under a worst drought condition. At the time, Albemarle County staff estimated Crozet would have a population of 17,101 by 2035, which would use an estimated 1.59 mgd.
Gannett Fleming said that the Beaver Creek Reservoir would be a sufficient water source up until 2035.
AECOM now forecasts that in 2035, the same year evaluated by Gannett Fleming, Crozet will have a water demand of 0.69 mgd for 9,581 people, numbers that are 57 percent and 44 percent lower, respectively, from the 2007 estimates.
“We have better disaggregated data than what Gannett Fleming had,” said Shorter. “We know the per household consumption in Crozet. We are using Crozet numbers for Crozet, and I think that really helps.”
Developing a new 50 year water demand forecast with population estimates that reflect the revised Crozet Master Plan, AECOM now projects that Crozet will need 0.98 mgd in 2060 to serve a significantly smaller population of 13,600. While AECOM is focusing on the demand side of the equation, the data indicates Crozet’s Beaver Creek Reservoir will now last at least 25 years longer than previous projections.
Shorter said “lots of little things” probably contributed to the trend of lower water usage over the last eight years, including permanent shifts in water conservation.
“In the Gannett Fleming study, they saw a 20 percent drop in per capita water use in fiscal year 2003,” said Shorter. “They saw that year as an outlier in the data and they threw it out, just as I would have done because it was during a drought, but now we have eight more years of data at that lower number, and we are going to use that.”
According AECOM’s report, Crozet had a population of 5,562 in 2010 and current water usage is up from 0.31 mgd in FY 2003 to 0.37 mgd in FY 2010. Shorter said 73 percent of Crozet’s water supply was used by single-family residences and that Crozet residents use on average 68.3 gallons of water per capita per day. By comparison, the city of Charlottesville averages 107.1 gallons per capita day.
“It shows there is a good conservation ethic here today,” said Shorter.
“Per capita usage is fairly low ,compared to other communities across the country, across our planning region,” said Thomas L. Frederick, Jr, RWSA’s executive director. “That means people take water conservation seriously and a lot of water conservation measures have already been adopted.”
Today, the RWSA is holding two additional public meetings to review the AECOM forecasts. The Scottsville area water plan will be reviewed at 10:00 a.m. in Scottsville’s Town Council Chambers. The Charlottesville and Albemarle County urban area water plan will be reviewed at 6:00 p.m. at Burley Middle School on Rose Hill Dr.