Groundwater and stream interaction is important for water management and ecology. Researchers used time series analysis of groundwater levels near a stream to estimate exchange fluxes. By analyzing fluctuations in groundwater levels, they could separate the effects of rainfall and river levels on groundwater. This helped them understand how river level changes affect nearby aquifers and estimate parameters controlling groundwater-stream exchange. The method is simple and can be used to quantify exchange fluxes in the field.