Articles by Anoop Asranna

During the Open City biodiversity datajam held in December 2025, our group examined the ecological trends around Bengaluru’s lakes. Our analysis suggests a majority of waterbirds are declining across the city's lakes. Earlier, we addressed crucial questions on how migrant and resident waterbirds are surviving across 14 of Bengaluru’s lakes, how the shape of the lakes influence microhabitats, and how a scoring system can be used to record the decline in lake quality and bird populations. The last of our four-part series turns its attention to an individual site. As part of this study of waterbirds in 14 city lakes,…

While bird detection trends over the years clearly point to the decline of Bengaluru’s shoreline and vegetated-edge habitats, numbers alone tell only part of the story. In Part 3 of this four-part series on the state of the city's waterbirds, we have used a scoring system to understand how stressed the lakes and the microhabitats within the lake are, based on the bird diversity they support. We explore how lake shape, permanent inundation and shifts in citizen-led management might explain why some lakes may thrive as wetlands while others collapse.  For instance, at Kasavanahalli, the Pied Kingfisher and the Coot…

Since Bengaluru’s lakes were formed by damming water flowing down valleys, they are typically wedge-shaped, with a gentle slope and a deep basin towards the embankment. This promotes the growth of diverse vegetation and animals, each adapted to a particular water depth. The result is a natural zonation – reedbeds and shoreline vegetation at the edges, floating and submerged vegetation in the middle, and open water at the deepest end. During the Open City biodiversity datajam held in December 2025, our group examined the ecological trends around Bengaluru’s lakes. In an earlier article, we examined how migrant and resident waterbirds…

Lying at an altitude of 920 metres in the rain-shadow area of the Western Ghats, Bengaluru’s geography and climate do not support a perennial natural water source. Instead, a north-south ridge divides the city into three primary valleys: Hebbal, Koramangala-Challagatta, and Vrishabhavathi. Rainwater draining down these slopes feeds a network of small streams — forming a cascading lake system that the city historically relied on for its water supply. During the Open City biodiversity datajam held in December 2025, our group examined the ecological trends around Bengaluru's lakes. Data on insects, spiders and flora on platforms like iNaturalist were insufficient…

Bengaluru has experienced extreme weather fluctuations this year. After a severe heatwave, the city enjoyed a brief respite with heavy showers, resulting in a record 111.1 mm of rainfall earlier this month. While Bengaluru received excess rainfall, the rest of the state is grappling with a 38% monsoon deficit, affecting water storage levels in reservoirs. The city is still facing water shortage despite heavy rains. In this multi-part series, analysts at the OpenCity water datajam, examined the level of water security (or lack thereof) in the areas/wards and provided insight into the redressal mechanisms: Part 1: Is your neighbourhood ‘water-secure’?…

(In Part 1, data analysts explained how they arrived at a definition of water security. In Part 2, the analysts explained the methodology used in estimating the Cauvery index and the results have been obtained. In continuation, part 3 will explain the methodology used in estimating the remaining indices and its results) Groundwater index Borewell count: The OpenCity borewell dataset was used to map borewells into Bruhat Bengaluru Mahanagara Palike (BBMP) wards and compute the number of borewells per ward. Assuming an average yield of 5,000 litres/day, water supply from borewells was normalised with ward population and the wards were…

(In Part 1 of the series, data analysts explained how they arrived at a definition of water security and created a location-specific index. In Part 2, the analysts will explain the methodology used in estimating the use of the Cauvery index and how the results have been obtained) The variables (below) were indexed and weighted with the Cauvery index, which was prioritised due to its significant impact on Bengaluru’s water security. Groundwater and land-use indices, being interdependent, received equal weights, followed by the governance index. Here is a summary table: Parent IndexVariableWeight AssignedCauveryCauvery supply to Ward1GroundwaterBorewell Water supply (litres/person/day)Ward area…

Bengaluru’s water crisis hit new lows in March 2024, which led to disruptions in water supply. There are areas in the city where water supply is irregular, expensive and unpredictable, bringing the daily lives of many communities to a standstill. It was this issue that made us, as a group, tackle the issue of water security at the Bengaluru Water Datajam held by Opencity.in in March. The notion of water security is a tricky problem to address. It depends on multiple factors like ecological security, risk management of the city, to name a few (Aboelnga et. al., 2019). Therefore, we…