The researchers studied how much water evaporates from grassed swales and bioretention cells in Auckland, New Zealand. They found that bioretention cells lose more water than grassed swales. The amount of water lost varies depending on the season. The researchers suggest that using soil moisture levels can help estimate how much water is evaporating from these systems. They also found that current climate data may not accurately predict water loss from grassed swales. More research is needed to better understand how different factors affect water evaporation from these systems.