The data set contains inflow and outflow data recorded in a bioretention cell. The data comprises raw water level measurements collected with a pressure sensor in monitoring wells in the inlet and outlet pipes of the structure. The bioretention cell was designed and built with long-term monitoring in mind. It has an impermeable layer preventing deeper infiltration of water. The outlet pipe drains directly into the "Kuninkoja" stream. Due to the position of the outlet pipe, backflow of stream water into the bioretention cell might occur under high discharge conditions. This should be taken into account when evaluating the outflow data. The data set comprises observations between February 2022 and October 2024.

2024