The Mithi river and the Mahim creek in the island city, the western suburbs of Borivli, Gorai, Dahisar and Bhandup, Mulund and Mankhurd in the eastern suburbs have been worst hit by reclamation after 1970, according to an ongoing study by the Maharashtra Transformation Support Unit (MTSU).
Most reclamation has been done in the inter-tidal zone, which comes under coastal regulation zone I, leading to shrinking wetlands and mudflats along these regions, the report states.
“Reclamations have affected the natural drainage channels in low-lying areas that contain excess water during floods. With concrete replacing open spaces, percolation has reduced drastically. Creeks and rivulets, know today as nullahs have become shallow, filled with siltation due to increased built up area,”
said Professor Sudha Srivastava, reader, geography department, Mumbai University and co-author of the report.
The report has used remote sensing imagery, topographic maps that detailed the city’s changing land use over the years and Google earth imagery that showed the changes in land use.
Data for the study was sourced from the city’s pre-independence city gazetteers and government agencies.
According to one author, data on reclamations after 1980 was thin as several places witnessed illegal reclamations.
The study also traces the history of crucial reclamations that linked the different Islands. Most notably, Colaba, Mahalaxmi, Dongri, Parel, Worli and Mahim became a contiguous landmass as a result of filling up the sea and its inlets.
MTSU officials said though they don't accept the report’s conclusions on ecological damages, it gives them a perspective on past mistakes of reclamation.
“We will vet the report with the help of oceanography experts. This study has been carried out for a historical perspective on reclamation. Mistakes have been made in the past while reclaiming land,” said Sulakshana Mahajan, urban planning researcher with the MTSU.
“Experts have briefed us on how Dadar beach has witnessed erosion because of incorrect reclamation on the Bandra side of sea link. But we have also seen the advantages of reclaiming land for creating space in the city,” Mahajan said.