Resilience Scanner

Mumbai Automated Weather Station Network for Rainfall Monitoring

Solution Overview

Decadal rainfall data from the Brihanmumbai Municipal Corporation's Automated Weather Stations reiterates the increasing frequency of very heavy and extremely heavy rainfall events in Mumbai.[1] The BMC completed the installation of 60 additional automatic weather stations throughout Mumbai, increasing the total number of stations to 120.[2] The rainfall data collected through this expanded network helps the BMC send warnings to citizens and strategically prepare and implement disaster plans during heavy rainfall.[2]

Technical Components

The automatic weather stations provide information related to rainfall, wind speed, temperature, humidity, and wind direction.[3] These stations collect information on 28 parameters in all and are connected to the Emergency Operation Centre at the BMC headquarters.[4] The weather stations are connected to a central server located at the Worli data centre of the civic body.[5] The data is sent to this central server at regular intervals and updated every 15 minutes on the civic disaster management portal.[4][5] The gathered information is updated on dm.mcgm.gov.in.[6] Additionally, 165 automatic rain gauges installed by the Indian Institute of Tropical Meteorology, BMC, and IMD are used to collect rainfall data.[7] The successful bidder for the 60 new AWS was expected to integrate the new stations with the existing disaster management website and mobile app.[4]

Implementation Details

Around 43 AWS were installed by December 2023, while the remaining 17 were set up in the past three months, with the installation cost of each AWS up to INR 7 lakh.[2] The BMC had planned to install 60 additional automatic weather stations across Mumbai during the monsoon, but only 43 were set up initially and 17 were underway due to technical difficulties and security reasons.[6] The National Centre for Coastal Research recommended installation of 97 additional AWS throughout Mumbai to obtain accurate rainfall measurement and enhance the flood prediction ability of the Integrated Flood Warning System developed by NCCR.[8] Due to cost and security issues, the civic authority decided to install only 60 AWS.[2] The NCCR submitted grids to BMC for identifying locations where the AWS would be installed, and the civic body's disaster management department estimated about 60 feasible grids.[4] Most of the automatic weather stations were installed on rooftops of BMC or government buildings, while a few were installed on ground.[4] The installation work started at locations such as schools, residential societies, and hospitals.[6] Specific installation sites included the municipal school on Gokhale Road at Dadar (West), Khar Danda pumping station, Versova in Andheri (West), and Pratiksha Nagar school in Jogeshwari (West).[2] Many of the existing AWS were installed at fire brigade stations as they are the first respondents during disasters.[4] The contractor is responsible for maintaining the AWS as well as the disaster management portal for three years.[2] The BMC floated tenders for installation of the 60 AWS, with the bidder also responsible for displaying real-time rainfall data and maintaining the Disaster Management website and app.[8]

Benefits and Impacts

Decadal data from 2011-2020 accessed from 37 weather stations showed that Mumbai experiences an average of 6 heavy, 5 very heavy, and 4 extremely heavy rain events per year.[1] Between 2017 and 2020, there was a steady increase in extremely heavy rainfall events.[1] The analysis showed that most extreme rainfall events tend to last only a single day, while 17% of very heavy and 21% of extremely heavy events last more than a day.[1] Spatially, most extreme rainfall events tend to occur as localized clusters in western and central areas, such as Worli-Dadar, Kurla, and Andheri.[1] The weather stations are installed at a distance of every four square kilometers to provide citizens with micro-level information.[6] After installations are complete, there is an AWS every three square kilometers as opposed to the previous eight square kilometers.[3] According to the IMD, Mumbai has one of the largest weather monitoring networks in the country.[3] The BMC's Disaster Management app currently gives weather data—temperature, wind, humidity, and pressure—in 140 locations in the city.[7] Through the BMC's Disaster Management app, areas likely to be waterlogged are flagged anywhere between six to 72 hours in advance, along with the probable height of floodwater and location-specific risks.[7]

Climate Adaptation Relevance

The analysis initially focused on examining the pattern of extreme rainfall events across various regions of Mumbai, using data obtained from AWS.[9] The Integrated Flood Warning System was installed in Mumbai in 2020 and factors in the amount of rainfall, tide levels, topography, land use, drainage, population, and the level of water in the rivers.[7] Last year, the BMC asked IMD to provide warnings specific to an area, time, and intensity of rainfall, following an incident on August 29, 2017, when it predicted extremely heavy rainfall in two locations, but the city came to a grinding halt after receiving more than 200 mm of rain at over 20 locations.[3]

[1]: Source 1 [2]: Source 2 [3]: Source 7 [4]: Source 3 [5]: Source 5 [6]: Source 5 [7]: Source 6 [8]: Source 3 [9]: Source 4

Sources