Last week, the Po River reached a discharge level not seen in years. On Sunday, April 20^th, 2025, the flow peaked at around 8,000 m³/s. At the Gussola oxbow lake—Open Lab 6 of the REWET project—the river overflowed its banks, flooding the surrounding fields for nearly a kilometer. All the riparian zones were inundated, and for several days, water remained on the land, most of which is normally used for poplar cultivation.

The oxbow lake was hydrologically connected to the river for over a week. We went out to sample greenhouse gases on a day when river water was still actively flowing into the system as shown in the following images.

Measurements taken with portable gas analyzers showed fairly uniform fluxes across all sampling points within the oxbow lake, likely due to the steady input of river water. Water temperature was 16 °C even if air temperature was already 25 °C!

However, in the more isolated, stagnant side pools, methane emissions were particularly high. Interestingly, we weren’t the only ones out there—several animal species were present too, suggesting that the influx of fresh water, following a long period of disconnection, may have improved water quality and boosted the overall health of the ecosystem.