Eight people were fined in court on Friday, after trespassing on areas restricted to the public at North and South Dandalup Dam.
Daniel Roy Tapley, 36, and Hailey Jasmine Ward, 29, pleaded guilty to unlawfully entering a Water Corporation zone which was not open to the public, when they appeared in the Mandurah Magistrates Court.
The pair were charged by rangers after their White Nissan Patrol became bogged on May 29, 2017.
At the time, Mr Tapley told rangers he had not seen the restricted access signs.
Ms Ward told the court the pair was not aware the zone was restricted and they had followed other vehicles into the area.
Water Corporation legal representative Conor Breheny told the court the maximum fine for the charge was $2500.
The duo were both fined $250, $280.60 costs and given spent convictions.
Timothy Brian Haines, 27, and Sarah Jayne Price, 26, were both charged with entering the same restricted dam zone on April 26, 2018.
The pair, who did not appear in court, were fined $300 each and $280.60 costs.
Nepia Aeii Hiwaii Teio, 43, had entered an endorsed plea of guilty and sent an apology letter to the courts for unlawfully entering the restricted dam zone in his Nissan Patrol and allowing his dog to swim, on December 1, 2016.
Mr Breheny said the maximum for allowing an animal in the area was $5000.
Teio was fined $600 and $280.60 costs.
Cody James Winter, 18, was charged with camping on land without authority and unlawfully entering the restricted dam zone in a Toyota Hilux on February 17, 2018.
Mr Breheny said Winter was with a group of friends at the time, and told rangers he had not see the signs.
Winter was fined $100 and $280.60 costs.
Brett Edward Foster Graeme Pickett, 25, did not appear on one charge of entering a prohibited zone at the dam on December 23, 2017.
Mr Breheny said Pickett was with two other men at the time, and had told rangers he was driving the vehicle.
Pickett was fined $100 and $280.60 costs.
Jake Benjamin Watt-Lee, 19, entered an endorsed plea of guilty to a charge of unlawfully entering a Water Corporation zone in North Dandalup Dam, in a red Hyundai Getz on December 23, 2017.
Watt-Lee was fined $300 and $280.60 costs.