Mumbai's Lost Lakes: A Revival Plan Amidst Climate Extremes

At a time when Mumbai is experiencing extreme climate events like heat waves and relentless waterlogging during the monsoon, the Brihanmumbai Municipal Corporation (BMC) administration has floated a proposal to carry out a survey and identify the number of natural lakes in the city that exist today. The move comes at a time when Mumbai is witnessing a series of redevelopment and infrastructure work, which has led to the reclamation or filling of many natural water bodies, including lakes and ponds, for development, causing a loss of ecological biodiversity.

Meanwhile, according to experts, natural lakes play a crucial role in micro-climate moderation by lowering temperatures in urban areas and mitigating the urban heat island effect. Some of the key lakes that still exist in Mumbai include the Tulsi Lake, Vihar Lake, Powai Lake, Sion Talao, Bandra Talao, and Banganga Tank. Of these, Tulsi and Vihar Lakes supply potable water to Mumbai daily.

Avinash Dhakane, Additional Municipal Commissioner, told the Indian Express, “The overall drive will be a multi-stage process. In the first stage, we will identify the locations in our city plan where natural water bodies are marked. Then we will carry out a survey to identify the present condition of these water bodies. If they still exist, they will be rejuvenated and developed into blue zones of Mumbai.” The primary objective of this project is to find the lost lakes to ensure that the urban heat effects are restored along with ecological sustainability. Dhakane also mentioned that the larger plan is to upscale the city’s overall urban infrastructure by rejuvenating these water bodies to make open spaces more accessible for people.

Currently, the project is in the planning stage. Once the entire modus operandi is developed, the project proposal will be drafted, and a tender will be floated to appoint consultants for this project.

In the past, Mumbai’s Development Plan (DP) of 1991 and 2034 indicated the presence of approximately 300 lakes in Mumbai. However, in the last three decades, due to various infrastructure and real estate projects, many of these lakes were reclaimed and filled by the authorities. According to a survey report by the World Wide Fund for Nature (WWF), 129 sites were identified via satellite imagery as potential sites for natural lakes in Mumbai. Out of these, natural lakes could be found in only 68 locations, while 17 locations remained inaccessible. The report also stated that several areas were found to be dug up as foundation pits where construction works had begun when the survey began.

Furthermore, the survey indicated that out of the total lakes that exist in Mumbai, 36 are medium-sized, 23 are small, 6 are large, and 3 are very large. Earlier, Mumbai had several natural water bodies in every pocket, and until the middle of the 20th century, people were largely dependent on these lakes for their daily water needs as pipelines hadn’t reached many places in the suburbs. However, after the real estate boom began in the 1980s, many of these lakes were filled. Additionally, many lakes were labeled as potential breeding spots for mosquitoes and were reclaimed to prevent the spread of malaria.

Environmental experts maintain that if the natural lakes are identified and rejuvenated, it will help create mitigation measures against flooding in Mumbai. Dr. Shashank Joshi, a hydrological expert and researcher, told the Indian Express, “Lakes serve as heat sinks, moderating the temperature levels of the space where they are located. At present, the overall temperature of Mumbai has seen a rise largely due to the urban heat effects of concreting work. The lakes will be able to control them.” Lakes are also a crucial ecosystem and act as natural water cycle regulators. They act as sponges, absorbing excess rainfall water, preventing overflow of rainwater, and acting as water catchments, thus avoiding water logging during the dry weather period.

The plan at a glance: - Identify, rejuvenate, and restore lost natural lakes in Mumbai. - Potential natural lakes as per BMC’s DP report: approximately 300. - WWF report states: - Potential areas of natural lakes as per satellite imagery: 129. - Locations where natural lakes actually exist: 68. - Types of existing lakes as per the report: - Small: 23 - Medium: 36 - Large: 6 - Very Large: 3 - Key advantages of having lakes in the natural environment: - Climate regulation - Flood mitigation - Biodiversity hotspots - Water purification and cycling - Groundwater recharge - Erosion control - Key lakes in Mumbai: - Tulsi - Vihar - Powai - Sion - Banganga Tank - Mahim Talao - Bandra Talao