City staff and environmental impact consultants delivered presentations on air quality and water supply to the Planning Commission on Tuesday.
Alan Sako, an air quality specialist with Impact Sciences, detailed how One Valley One Vision, the City’s proposed General Plan, addresses greenhouse gas initiatives set by AB 32 and SB 375. Both pieces of state legislation outline standards for reducing harmful gases to 1990 emission levels by 2020.
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As required, the analysis for OVOV’s Environmental Impact Report follows guidelines established by the California Environmental Equality Act, South Coast Air Quality Management District and California Air Resources Board.
To meet these guidelines, OVOV encourages transit-oriented and mixed-use development as density increases, Sako said.
Nevertheless, greenhouse gases remain a concern, especially when a large percentage originates outside City limits  in the Los Angeles Basin.
“The increase in GHGs is considered a worst case scenario,” said Sako. “Each of the pollutants carries its own health concern.”
City Planner Dave Peterson said the City has employed several strategies to reduce emissions, such as educating the public through its growing website greensantaclarita.com .
The Institute for Local Government will use Santa Clarita as a case study, in part due to its success with green programs, Peterson said.
Tom Worthington, owner of Impact Sciences, spoke on behalf of Castaic Lake Water Agency, the water wholesaler for Santa Clarita.
Worthington said groundwater supplies met drinking water standards; in particular that it was not at risk from perchlorate.
Worthington’s presentation provided estimates for water supply and demand at build-out by 2050 during a normal year, single dry year and a multi-year drought. Inside the CLWA service area, supply exceeded demand in each category.
During a normal year, demand would be 135,450 acre-feet per year with a supply of 138,507 afy.
According to CLWA Water Resources Manager Dirk Mark, acre-feet per year is the quantity of the area of one acre filled up with one foot of water.
“It’s roughly the size of a football field if your visualize that covered with a foot of water,” he said. “The amount of water a household uses in our valley is somewhere between half to three-quarters of an acre-foot of water.”
Marks said the demand estimates provided in OVOV were accumulated by the valley’s four water retailers.
Water supply and demand for areas outside the CLWA, however, were not as absolute.
“Groundwater supplies outside the CLWA service area are not fully understood, and are constrained,” Worthington said. “Most of the areas are fractured rock.”