A man was arrested on suspicion of assault following a clash between a group of men at a trouble spot in Tring.
Police were called to Pitstone Quarry, in Icknield Way, at 5.26pm on Monday when the trouble kicked off.
Several police cars and an ambulance attended the scene and a 27-year-old man was arrested and has been kept in police custody while investigations are on going.
The quarry is a trouble spot on hot days because people go there to swim in the lake, despite the owners of the site fencing it off and saying that they are not welcome.
Sometimes up to 200 cars can be found up there and police officers have warned people of the dangers of swimming in the lake as there are no safety measures.