HYDRAULIC FRACTURING AND POTENTIAL GROUNDWATER CONTAMINATION IN KERN COUNTY, CALIFORNIA 2012

Hydraulic fracturing has been occurring in California for many years with few regulations and little environmental and public health monitoring. For example, before emergency regulations came into effect in January 2014, chemical disclosure was done only on a voluntary basis. The main difficulty has been the availability of detailed comprehensive data. To help with this issue the State of California is currently writing draft regulations for Senate Bill 4, a bill to regulate hydraulic fracturing and prevent against groundwater contamination.

In order to identify possible groundwater contamination, we present a database of 569 voluntarily disclosed hydraulic fracturing operations in Kern County during 2012 from FracFocus. These locations are plotted against over 7000 groundwater wells that were sampled by the USGS and are available on the National Water Information System website (NWISWeb). A small percentage of Class II disposal wells that are monitored by the EPA are also included. Data was combined in ArcGIS and used to find where routine water quality testing should be performed to find potential contamination in aquifers.

In Kern County fracking occurs as shallow as 860 feet, mostly in the hills lining the west side of the San Joaquin Valley where few groundwater wells are located. The hydraulically stimulated fields that contain some of the highest concentration of groundwater wells are in the Rose and Shafter oil fields. However, these fields have some of the deepest wells, and several thousand feet separate fracking activity from aquifers. This large difference in depth makes direct contamination by frack fluid less likely. Indeed, the main source of contamination may be produced water, hydrocarbons, and improperly disposed flowback.

Our preliminary results indicate that the current suite of water quality data is not sufficient for accurately detecting aquifer contamination from frack fluids. We present a monitoring plan that was created using flow nets to show ideal locations to routinely test the water quality in and around the Rose and Shafter oil fields. Although most fracking operators use different chemical ingredients it would be useful for each frack operation to have a unique “chemical ID” to trace back to its original source.