THE USE OF TIME SERIES ANALYSIS TO REDUCE GROUNDWATER MONITORING WELLS: AN INDIANA CASE STUDY

Groundwater monitoring is pertinent to the understanding of wetland hydrology especially when alterations are made to the geology of an area. One such example is in Fox Island County Park and Preserve, Allen County, in NE Indiana. The park is a major environmental education resource in NE Indiana and the focus of the park is education. The park that was a groundwater discharge zone is now a recharge area due to anthropogenic activities, and the understanding of the hydrology of the area would be helpful in the planning and use of the park. Twenty monitoring wells drilled to several depths, ranging from 10 feet to 200 feet, have been monitored constantly from 1996 to 2002. Access to some wells and use of personnel is becoming a major problem as trained personnel to monitor wells is dwindling. To get useful data with fewer monitoring wells, we did time series analysis on available well records.

Time series analysis of the well data suggests that there are strong correlations between fifteen pairs of wells in the park. A correlation coefficient of 0.9 with p-value of approximately 0.0 is the decision rule for the chosen pairs of wells. Besides the correlation and p-values, the locations and ease of getting to the wells will be used to decide what wells to be monitored continually. This exercise of decommissioning some monitoring wells will ensure continued gathering of useful data in the study area.