The field day was part of the Linking Landscapes project, which aims to work in rural and semi-rural schools in Otago and Southland to highlight the effects of different land-management practices on water quality and native biodiversity.
Pupils from Kakanui, Maheno and Five Forks schools met near the river mouth at Kakanui and walked along the estuary to the bridge.
They then went to Clark's Mill, Mill dam and a dairy farm at Maheno before having lunch at Gemmells Crossing.
In the afternoon, they learned about galaxiids and invertebrates in the Kauru River.
Freelance environmental educator Katherine Dixon said the project had three stages.
The first was the children finding out about and exploring their catchment.
Second was a vision-planning workshop, where the children planned how they wanted their catchment to be.
The third stage was taking a positive action, such as tree planting, to improve the catchment.
Totara School is also involved.
