Summer has not yet begun but anti-social behaviour problems have already started at Bawsey Pits after an arson attack at the weekend.
Grassland and trees were burned on Sunday afternoon after a blaze had been sparked in the grounds.
Firefighters from Lynn were called to the bank near the lagoon shortly before 5pm.
A total of 400 metres of grassland, some trees and an electricity pole were damaged by the blaze, which had been started between noon and 5pm.
Police have now launched an investigation and are appealing for witnesses.
Current owners of the site, Sibelco, is urging people with information to come forward.
A spokesman said: “We are very disappointed to hear that this has taken place.
“We would encourage everyone to cooperate fully with the investigation and to share with the police any information that they have. We will cooperate fully with the authorities.
“Incidents such as this are not only damaging to the environment but hazardous.
“We thank the emergency services for their efforts in making sure the fire was not any worse than it was.”
Bawsey Pits, which was designated as a public space 30 years ago by Norfolk County Council, is popular with dog walkers and families but it has seen a number of deaths along with issues with vandalism and anti-social behaviour.
In 2013, a double tragedy occurred at Bawsey when 41-year-old Lynn man Ryan Pettengell and Umar Balogun, 16, from London drowned in a lake.
Sibelco is in the process of selling the beauty spot to Wisbech businessman Kevin Salter.
The sale is progressing through the legal stage.
Mr Salter is planning to create a country park which could not only boost the local economy but also create new jobs.
A planning application will be lodged later in the year and the park will be developed within three phases.
The first phase will see the introduction of managed and charged car parking with disabled spaces and secure cycle areas.
While the country park remains open, the access routes around the site will be looked at to best serve visitors.
A bus stop within the site along with dog-free zones to protect certain wildlife areas are also planned.
There are hopes for toilets and a café within this stage.
The second phase will include viewing platforms and decks along with pods to observe the wildlife.
Mr Salter will be working with RSPB and Norfolk Wildlife Trust.
There are plans to create a 24-hour CCTV wildlife viewing system. Estate rangers could also be leading school parties and other groups on walks.
There is also the potential for a restricted swimming area, subject to safety surveys.
This phase will include a cycle repair and hire centre, sailing and a restaurant, which may have a floating terrace.
Phase three will include an adventure play area for children, tree top activities and a conservation and eco visitor centre. Green holiday lodges and a small camping site are also part of the plan.
Anyone with information on the latest arson attack is asked to contact the police on 101.