WATER hyacinths have invaded the waterways in Songjiang District.

A warm winter and rising tide levels are behind this year’s early outbreak of the aquatic plants, officials said.

Workers in upstream Songjiang and Jinshan districts have stepped up efforts to clear the invasive species to prevent it from floating into Suzhou Creek and Huangpu River.

Wang Lulu, an official with the water management department of the Shanghai Greenery and Public Sanitation Bureau said that about 1,400 tons of water hyacinths have been removed daily in more than 10 river courses, including Sijingtang and Sanguantang in Songjiang.

Two temporary settlement spots were set up in Sijing and Sheshan towns to improve efficiency, and workers are clearing waterways from 4:30am.

There are 72 boats clearing over 10 key river courses in Songjiang and the frequency of removal has increased significantly recently, officials said.

The number of boats will be further increased and more prevention facilities will be put into use in the upstream areas, water affairs authorities in Songjiang said.

“Water hyacinth outbreaks usually happen in September, but the warm winter last year, current sunny weather and rising tide levels all lead to the unprecedented early outbreak,” said Wang.

She said the plant tends to grow faster in temperatures between 25 and 30 degrees Celsius.

The battle against the invasive species will be intensified during the flooding season, Wang added.