A New Way of Viewing Groundwater-Level Data
Traditional water-level hydrographs are graphic representations which show groundwater-level changes plotted against time. The long-term hydrographs are excellent for showing how groundwater levels have fluctuated throughout the period of record for the wells. However, the hydrographs do not show how the water-level changes relate to other factors such as the aquifer and well construction.
Strathydrographs show how the water-level characteristics of the observation wells relate to the subsurface geology at the well site, the hydrogeology of the aquifer or aquifers the well penetrates, basic well construction information, and the earliest water-level measurement collected from the well. High-quality graphic geologic logs are available for about half of the observation wells. Where available, the graphic log, or geologic data extracted from the log, is incorporated in the strathydrograph. Many of the observation wells that have no geologic log are located close to other wells for which logs are available. In these instances, the nearby logs are used to estimate the positions of the various geologic formations the well penetrated. The log identification numbers used to estimate the geology are shown on the strathydrographs.