comparison of several approaches to monitor water-table fluctuations

Relationships established between redoximorphic features and the seasonal high water table should be based on the most accurate representation of water-table fluctuations. In this study, we compared hydrographs developed using water-table readings made at weekly intervals over a 12-wk period to those developed over the same period for an adjacent water-table well using measurements recorded every half hour by a data logger. The hydrograph developed using the weekly readings underestimated the height of the water table for 33% of the study period. A simple inexpensive maximum water-table recording device (MWTRD) was developed to record the highest level the water table reached during the interval between site visits. Two approaches are demonstrated for improving the accuracy of the weekly hydrograph using data collected by the MWTRD along with a limited amount of logger data. These adjusted hydrographs accounted for >80% of the underestimation of the height of the water table compared with the weekly measurements.