Cod Beck reservoir, near Osmotherley, has been a popular picnic spot for decades, but as visitor numbers have increased, so have incidents of illegal overnight camping, inconsiderate parking, criminal damage and graffiti.
The parish council, Hamblet
on Council, North Yorkshire Police, National Trust and North York Moors National Park Authority have been working with owners Yorkshire Water to combat the problems.
Drivers obstructing through traffic by parking on grass verges have already been issued with fixed penalty tickets, registration numbers of cars have been logged and letters sent to owners behaving inconsiderately.
Hambleton Council has also applied for an order that will allow police to confiscate alcohol.
Now Yorkshire Water and the national park Authority have joined forces with the National Trust to employ a ranger who will patrol the area.
He will remind the public about the ban on overnight camping and the lighting of fires, urge visitors to leave their vehicles in designated car parks and record incidents of anti-social behaviour.
Yorkshire Water's catchment and recreation manager, Geoff Lomas, said: "It's hard to understand why some people who head for Cod Beck Reservoir to enjoy its peace and tranquility sometimes seem hell-bent on destroying as much of it as possible.
"They move into the woods with their tents – sometimes setting them across footpaths – chop down trees to fuel camp fires and then leave behind piles of rubbish including disposable barbecues, beer cans and bottles for someone else to clean up.
"Such behaviour beggars belief, but what concerns us more is that, despite two people drowning at Cod Beck since 2004 and numerous signs around the shores of the reservoir, there are people who are still prepared to ignore the risks and go for a swim.
"Cold water kills and it's not a pleasant way to die. You may think you're a strong swimmer but the water in Cod Beck never rises above 12 degrees centigrade and quickly penetrates the body's defences."
Working in partnership with the Hambleton Community Safety Partnership and the emergency services, Yorkshire Water has funded a DVD aimed at young people, entitled Dying To Be Cool.
