The Times of India                  07.06.2013

BMC adds 33 weather stations for area-specific flood control

MUMBAI: This monsoon, Mumbaikars will be able to know how much it rained in their locality every 15 minutes: the BMC has increased its automatic weather stations to 60 from 27.

The weather stations have been added to measure rainfall variation with accuracy in a more representative way. "Till last year, we had one automatic weather station for every 10 sq km. Now it is one for every 4 sq km," said Mahesh Narvekar, head of the BMC's disaster management cell. The weather stations have been added in conformance with flood preparedness guidelines of the National Disaster Management Authority (NDMA), drawn up considering rapidly changing rain patterns.

"Most of the new weather stations have been installed at fire stations and ward offices," Narvekar said. Each has a tipping bucket rain gauge system comprising a funnel that collects rain water and channels it into a small seesaw-like container . "This is how rainfall is measured: A drop of rain makes 0.25 mm of the gauge container. Thus, two drops on each side of the container (totalling four drops) make 1 mm of rainfall," Narvekar said.

The data is sent to a console through an electric signal. "An IP address is given to each console , which sends the measurements to the data centre," he said. "The data is collated and put on the BMC's monsoon website, where rainfall data is updated every 15 minutes. The website will go live when the rainy season starts and will remain so for the four-month duration of the monsoon."

Though the BMC's automatic weather stations are active throughout the year, the civic body collects information provided by them only during the monsoon months. "Our weather stations record temperature , wind direction and atmospheric pressure every day for all twelve months. But we do not collect and analyze this data as we are interested only in rainfall measurements ," Narvekar said.

The Met department, too, is getting 30 additional weather stations. At present, the department has only two weather stations in the citythe ones in Colaba and Santa Cruz. "We have got approval from the government to initialize the Megacity forecast system in Mumbai," said K S Hosalikar, scientist, IMD. "The Indian Institute of Tropical Meteorology will help us set up new weather stations in the city in 2013-14 ."

Observation points

From this year onwards, the BMC will get rainfall data from 60 weather stations, two of which are yet to be installed. The rest are functional

New 31

Colaba, Malwani, Mandavi, Nariman Point, Rawali Camp & Vile Parle (Wireless) fire stations; ward offices in B, C, D, F-North , F-South , G-South , H-West , K-East , K-West , L, M-West , N, S and W-South wards; Malbar Hill; Tulsi lake; Bhagawati, KEM, Kurla Bhabha, Nair and Grant Road Eye hospitals; engineering hub in Worli; Sion-Panvel octroi naka, SWD workshop in Dadar; Bhandup

Old 27

Andheri, Bandra, Borivli, Byculla, Chembur, Chincholi, Dadar, Dahisar, Dharavi, Dindoshi, Gawanpada, Kandivali, Kurla, Marol, Memonwada, Mulund, Vikhroli, Vile Parle (Wired), Wadala, Worli and BKC fire stations; BMC HQ building 1; BMC HQ building 2; Colaba IMD observatory, Deonar, Goregaon, Malad

Automatic rain gauges

At its weather stations, the BMC has installed tipping bucket rain gauges. Each consists of a funnel that channels water into a small seesaw-like container

After a set amount of water collects, the seesaw tips, dumping the water and sending an electric signal

The data is sent to a console, from where it reaches a data centre and finally to the BMC's control room, which updates the information every 15 minutes on its monsoon website

The website will be activated once the rainy season starts.