River Tapi runs through the city of Surat and is heavily polluted resulting into depletion of the river ecosystem and overall environmental degradation of the area. 44 outlets have been identified that contribute more than 525 MLD sewage flow (including 155 MLD secondary treated sewage as per GPCB consent) to River Tapi during non-monsoon days. River Tapi being the prime source of water for the Surat city; an urgent need has arisen to abate pollution of the river Tapi.
With the financial participation of the nearby user industries, a weir cum causeway was constructed by the Surat Municipal Corporation (SMC) on the river with twin objectives of
Presence of red colored larva (Chironomus) was reported in the treated water at the consumer end in the year 2001. Considering the gravity of the problem, SMC retained National Environmental Engineering Research Institute (NEERI) to Investigate into the occurrence of Chironomus in the water supply, evaluate performance of one of the water treatment plant and suggest suitable measures. The important part from the report by NEERI, related to the disposal of untreated sewage into the river tapi is briefly described below, which shows the importance and necessity of the project.