An unexpected finding while looking for water
During our field visits across the upper reaches of the Arkavathi River System, we were seeing many lakes remain dry or hold very little water.
Then came two years of exceptional rainfall.
Our earlier analysis on Paani.Earth of 122 years of rainfall data for the Hesaraghatta catchment showed just how unusual these years were. The June–December monsoon rainfall in 2022 was 1,263 mm, 94% above normal and the highest in 122 years. The previous year, 2021, had recorded 1,118 mm, 72% above normal, making it the second-highest in the historical record analysed.
With so much rain, we wanted to understand what this meant for the Arkavathi and its lakes. Had the lakes filled? How much open water could we see? And how did this compare with what we had seen historically?
Looking at the lakes from above
We began analysing satellite imagery to measure the extent of open water across the lakes and compare it with historical rainfall patterns. But something unexpected showed up.
After the exceptional rainfall of 2022, several lakes had filled and overflowed. Yet when we looked at satellite imagery, the open water across many lakes in the Hesaraghatta catchment appeared fragmented.
There were gaps between the water pixels where we expected to see water. We looked more closely using historical Google Earth imagery.
There were trees growing on the lakebeds.
This led us to a much larger investigation
What began as an effort to understand where the water was led us to investigate how widespread trees were on lakebeds, why they were there and what this could mean for the lakes themselves.
Through satellite imagery, spatial analysis, field visits and conversations with fishermen, farmers, researchers, citizens and government officials, we explored the scale of the issue and its implications for water storage, water quality and aquatic biodiversity.
Learn about what our findings were and the questions it raised.
