EL CERRITO -- In the wake of a favorable ruling by a state appeals court, the West Contra Costa Unified School District is moving forward quickly with plans to demolish shuttered Castro Elementary School and start construction on a new Portola Middle School on the Donal Avenue site.

The project has been delayed six years while the school district rebuffed a legal challenge brought by a group seeking to save Castro Elementary. On Thursday the 1st District Court of Appeal unanimously upheld a lower court's finding that the district had not violated the California Environmental Quality Act and the Brown Act.

"Obviously we're very, very relieved," said school board President Charles Ramsey. "Now we can move forward and build the new Portola school at the Castro site."

Michael Srago, the lead plaintiff for the group trying to block the demolition, and Robert Brower, attorney for the plaintiff group, did not immediately respond to requests for comment.

Castro Elementary was closed in June 2009. Portola Middle School -- located approximately a half-mile from the Castro campus -- was deemed seismically unsafe in 2009 by a state inspector. Portola students have been taught in temporary buildings on school grounds since 2010.

Ramsey said construction should begin at the Castro site in about six months.

"We're going to get designs, bid it out and move full speed ahead," he said.

Though an appeal to the State Supreme Court is

"They could, but come on," he said. "They appealed, and they lost."

Ramsey said the new school is expected to open for the 2015-16 school year and have an enrollment of 600 students.

Contact Gary Peterson at 925-952-5053. Follow him on Twitter at twitter.com/garyscribe.