Warm winter adds to hyacinth’s rapid growth

SURAT: Tapi riverbed is under the cover of

water hyacinth

for the first time in 15 years during winter season.

Generally, when temperatures rise in summer, water vegetation begins to grow in the riverbed. However, 35 degree Celsius temperature and stagnant water have led to abundant growth of water hyacinth this winter season in the river.

Unlike past years, city’s temperature in October and November this year has been 5 to 7 degrees Celsius above normal. Temperature in these months had never shot above 32 degrees Celsius in Surat. However, mercury has hovered around 35 to 37 degrees Celsius in these two months.

Water shortage in the river is another factor responsible for the growth of water hyacinth during the winter season. Ukai dam could just fill 57% to its capacity when the monsoon season ended. Dam authorities were not in a position to release water into Tapi. However, 220 million litres of sewage is daily released into the river. Temperature and nutrients in

sewage sludge

have helped the water hyacinth to grow in the riverbed. Environmentalist Nainesh Parekh told TOI, “A favourable climatic condition has been responsible for the growth of water hyacinth in Tapi riverbed during the winter season. We are seeing this for the first time is so many years.” Jayesh Dave, an energy auditor associated with Ganga Shuddhikaran project, said, “In order to remove water hyacinth permanently, we had experimented by releasing microalgae and some nutrients in Ganga water. The idea was to make this microalgae eat up all the nutrients available in the sewage sludge. We were successful in removing water hyacinth permanently from the Ganges.”