Arkavathi River Field Trip • April 2025
A big thanks to Professor Subodh Sharma (in the photo above) for introducing us to the world of macroinvertebrates. In April 2025, we spent a full day along the Arkavathi River doing a Rapid River Assessment by looking at the macroinvertebrates the river supports (or doesn’t).
What can macroinvertebrates tell us about a river?
Macroinvertebrates are small creatures that live in and around rivers and can be seen without a microscope. Insects and their larvae, snails, worms and small crustaceans are some examples.
A water sample collected from a river tells us about the water quality at that place and point in time. Macroinvertebrates can tell us a different story. Because they live in the river over longer periods, the community of creatures we find reflects the conditions they have been living with over time.
Some, such as mayflies and stoneflies, are sensitive to pollution and need relatively clean, well-oxygenated water to survive. Others can tolerate much poorer conditions. They also respond to changes in flow, loss or fragmentation of habitat and other disturbances. Looking at which ones are present and which are missing can therefore tell us something about the longer-term health of the river.
What emerged out of this field trip?
Our exploration with Professor Subodh through multiple trips to the Arkavathi and the Cauvery river also opened up conversations with the cCauvery team at IISc on the possibility of a wider citizen science programme for the Cauvery River Basin. That idea is now being explored further. We hope to share more as it develops.
