People overfeeding ducks at one of Cardiff's best-known landmarks have been partly blamed for a severe infestation of water weed.
The lake is suffering from long-term nutrient pollution
Over the summer months Roath Park Lake has slowly been turning into a blanket of thick green weed.
Cardiff County Council, which spent more than £400,000 dredging the lake last winter, has said measures have been put in place to rectify the problem.
Complex ecological reasons and the overfeeding of the wildfowl have been named as the causes for the weed build-up, rather than the dredging operation.
The overfeeding of wildfowl is contributing to the problem
Deputy council leader Marion Drake said: "I can understand that the appearance of the lake and the growth of waterweed is of concern.
"However, this is a naturally occurring process and the council is doing its best to ensure a proper balance is achieved between the leisure activities on the lake and environmental considerations".
In July the council said it was taking "decisive" action to remove the weed.
It said at the time: "When the work is completed, the lake should be returned to its normal appearance".
Unused food stuff has built up in the lake
The lake has long-term nutrient pollution which has been caused by waterfowl droppings and the build-up of unused food donated by the public.
The council has said the situation has been beneficial for wildlife and the weed died naturally in the winter.
Due to complex ecological reasons relating to changes in the numbers of fish and birds using the water, the lake changed its character during the 2000 season resulting in water weeds.
Operations to remove the silt from the north end of the lake during last winter were designed to return the lake to its original bed level.
The project was not primarily intended to affect the quality of the water or the waterweed.
A further £200,000 has been earmarked for phase two of the de-silting work which has been planned for October.
The council intends to seek lottery funding to upgrade the park and restore its original planting and infrastructures.