“The longer the record you have, the more powerful the data becomes,” said Lisa Senior of the U.S. Geological Survey (USGS), Pennsylvania Water Science Center in Exton. Senior was updating members of the Pike County Conservation District (PCCD) board of directors on the Pike County Groundwater Level Network established in 2007.
“Groundwater is the main source of water supply in Pike County and is the major source supply for streams,” Senior explained. The county-wide network monitors 24 wells, ranging in depth from 24 feet to 425 feet to assess the natural fluctuations of the water table.
The long-term data can be used for a number of applications, such as understanding seasonal changes, effects of climatic changes and potential impacts of water use upon groundwater levels and stream flow. It can also help to determine drought triggers, evaluate changes in groundwater storage, understand water budgets and estimate stream base flow.
PCCD staff currently make the measurements and send the raw data to USGS, which reviews it and enters it into databases for public distribution and long-term storage. USGS maintains a page called Groundwater Watch for observation wells across the country, including those in Pike County. The data is served up real-time, is available to the public for perpetuity and can be downloaded and used freely.
For Pike County, having this online data storage and display allows anyone to get access almost as soon as it comes in. Only five counties have such a network. In Southeast Pennsylvania, Chester County uses its network for drought assessment (http://pa.water.usgs.gov/projects/as  sessments/chesco/ground_water.php).
In terms of water conservation, the data can be used to address concerns about over-withdrawal of wells because of pumping in the area or because of drought. “If you have an ungauged stream and need to estimate what kind of stream flow you have, the groundwater levels should tell you, which may affect all kinds of things in terms of habitat,” said Senior. “Withdrawals from groundwater can affect how a stream discharges.”
USGS has done additional baseline chemical sampling of 20 Pike County wells during the 2012 summer season, which included analysis for constituents that might be present in brines or related to hydraulic fracturing. “Not the organic chemicals, but the brine chemicals, like the bromides, chlorides, lithium, boron and methane,” said Senior. “We also did nutrient profiles, radon, radioactivity and major ions. Subsequent to that, we’ll be following four wells monthly for a two-year period to see what the temporal fluctuations are.”
The five-year groundwater study has put Pike on its way toward enhanced water conservation, but continued monitoring is in order. “You need about 20 years of data to get a robust characterization of the range of hydraulic conditions,” said Senior.
A resolution to adopt the five-year study report was approved by the PCCD board of directors, along with a resolution to apply for a Scenic Rural Character Preservation (SRCP) grant to continue the study for three more years. The SRCP board has approved the grant application. A county contract and joint funding agreement from USGS are expected to be presented at the PCCD board meeting on October 15.
Visit the following links to USGS websites containing water-level data. See http://groundwaterwatch.usgs.gov/StateMaps/PA.html  for active groundwater-level monitoring sites in Pennsylva nia. See http://groundwaterwatch.usgs.gov/countymaps/PA_103.html  for active groundwater-level monitoring sites in Pike County.