The county is in the process of establishing a network of approximately 20 dedicated monitoring wells throughout the county for the purpose of long-term tracking of groundwater levels and quality. As of July 2009, there are more than a dozen dedicated monitoring wells in the network as shown on the map at left. Two monitoring wells have relatively long data records and are maintained by the U.S. Geological Survey. View a map of monitoring wells (PDF).
Some of the wells monitored by the county were constructed specifically for the monitoring program and others were received through the county's voluntary well donation program. These donated wells were unused wells that the land owners agreed to let the county use for long-term monitoring. Additional potential well sites are being evaluated for possible inclusion in the monitoring program.
Groundwater level data collected over several years from six of the county's monitoring wells are shown in the graph below. Note that the water levels tend to show a seasonal pattern with higher levels usually in late winter and lower levels in late summer. (The water level peaks in May 2008 occurred after heavy rain events in April and May.) Also note that the depth that groundwater occurs in the different wells varies considerably - from near land surface to more than 80 feet below ground level. This is due primarily to the different geology and land topography where each well was drilled.