Algae that can kill fish and other wildlife was found floating in a pond in Enfield.
The authority has now removed the green algae from the New River Loop in Gentleman’s Row after a series of complaints from ramblers.
It is believed the hot weather caused the borough’s waterways to suffer from a surge in the growth of the algae, also known as duck weed.
Park staff created pontoons made out of discarded timber pallets wrapped in a fine net and floated them down the river to push the weed towards staff with catch nets.
The recovered duck weed will be composted and used to nourish the soil in Enfield’s parks at a later date.
If left untreated or killed with chemicals, the dying weed in the shallow river would draw oxygen from the water and potentially be harmful to the fish.
Cllr Chris Bond, cabinet member for environment, said “Although naturally occurring, this algae is unsightly, and we often get complaints about it forming.
“We have used many different methods to try and reduce or remove it. This latest method, is completely natural quick and easy but seems to be doing the trick. We aim to remove as much as we can to keep the water clearer and benefit the fish and other wildlife that live in the water.
”It’s a great example of our parks staff finding an effective, cheap solution to a problem that’s dogged us for a while, and if we can use this technique elsewhere in the borough we’ll certainly consider it.”