A team of officers used garden rakes, sticks and tools to work their way searching through undergrowth at the site, which has been closed off by a police cordon.
The investigation will take some days to complete, it is understood, and will involve underwater search teams.
Claudia Lawrence was last seen in March 2009 and was reported missing from her home in Heworth after not turning up to her work as a chef at the University of York.
North Yorkshire Police has conducted two investigations and questioned nine people in relation to her disappearance and suspected murder, but no charges have ever been brought.
No information has been given by police as to what has prompted the new lines of enquiry, but Detective Superintendent Wayne Fox re-iterated yesterday that the focus was on bringing Ms Lawrence’s suspected murderer to justice.
He said: “I thank the public for the positive responses and new information received in support of the current phase of the investigation.
“Our focus is on finding Claudia and bringing those responsible for her disappearance and suspected murder to justice.”
Speaking after he took over as senior investigating officer in the case earlier this year, Mr Fox repeated the belief that several people know, or have suspicions about, what happened to the 35-year-old.
Earlier this week, Ms Lawrence’s mother, Joan, said the new searches have left her in “utter shock”.
Ms Lawrence’s father, Peter, died earlier this year after years campaigning to find his daughter.