Cheshire Police spent today (April 3) dealing with what they described as an 'ongoing incident' in the Hatchmere area.
They warned the public that this would restrict public access to certain areas throughout the day.
The force tweeted to say they are 'concentrating search efforts' in the area 'following reports of concern for a motorist seen in the vicinity last night'.
Hatchmere is a small lake and nature reserve in Delamere Forest.
Witness Claire McCormick wrote on Facebook: "We passed through this on our way home a few hours ago, was a huge police presence and CSI vans, didn't look good."
Wendy Ellis also posted: "Police asked to search a stream that leads off from the lake on to my parents property. Nothing was found though. Underwater search team are there."