A charity event that sees hundreds of fundraisers participate in a gruelling commando-style obstacle course in a Watford park has been objected to because "it is destroying the nature reserve".
Push it for Peace, a five-mile race through Cassiobury Park, which features a run through the river was set to take place in September.
But objectors say setting the course through the water in the park is disturbing the local wildlife and their habitats.
Park user Bob Alexander said it’s the equivalent of holding a car rally through a treasured national park in Africa.
He said: "The park information boards boast lots of exciting things about nature, including 10 different species of fish.
"Holding an event that has hundreds of runners going through the park, through the rivers and trashing the banks is totally incredible.
"It’s like having a car rally in an African nature reserve, with cars bombing around the animals."
The Peace Hospice put on a similar event last month which saw 200 participants run a two-mile obstacle course through Cassiobury Park’s waterways.
The River Run raised nearly £10,000 for the charity.
But Mr Alexander is concerned the water-based part of the courses is too destructive and should not have been allowed.
He continued: "At this time of year in Cassiobury Park there’s also birds nesting and frogs spawning.
"Nature reserves are sacrosanct and should never be subjected to this sort of behaviour."
Mr Alexander has contacted Watford Borough Council with his concerns.
"Nobody asked exactly what the event was about," said Mr Alexander.
"They didn’t seem to understand how destructive the race is."
In an email to Mr Alexander from Paul Rabbitts, environmental services client manager (parks and streets) with Watford Borough Council, Mr Rabbitts stated: "If this level of river usage had been known it would have been either turned down, or that element of the event disallowed.
"The Peace Hospice are excellent organisers and we have had no problems before and they were told that no obstacles were to be placed in the river and that they were allowed to cross the river near the weir."
Peace Hospice Care spokesman Jon Michael said: "We have become aware that some concerns have been expressed surrounding the partial use of the River Gade at our recent River Runner event.
"We certainly don’t want to carry out any activities which could damage the environment and will continue to work closely with Watford Borough Council and Veolia Environmental Services.
"Our ‘Push it for the Peace’ fundraiser which has become an extremely popular event will be taking place again on September 20 and we will be working closely to make sure that it has new and exciting challenges even if we need to change some of the route or obstacles. We can still guarantee that Push it for the Peace will be a fantastic event!"