Since it is practically infeasible to measure for all the individual contamination components in real time in the field, CWW has established lab verified, easy to measure surrogates that will indicate any change in the aquifer conditions.
|Public concern||Real-time Surrogate Measurement|
|Aquifer contamination by fracking fluid and/or produced fluids||Conductivity -- Total Dissolved Solids (TDS)|
|Methane leakage to aquifer||Oxidation-Reduction Potential (ORP) and/or Dissolved Oxygen (DO)|
TDS is chosen as a surrogate not because what it represents is of concern but because if any sort of produced fluid contamination did occur, this value for a fresh water aquifer would certainly change in a statistically important manner. In experiments being conducted at CSU, ORP and DO have been shown to correlate to the chemically reduced conditions that are present with non-transitory dissolved methane. Experiments have been conducted to quantify the response of the ORP/DO sensors to various dissolved methane conditions and this data will provide the basis for use of these parameters as surrogates for the presence of methane.
The real-time monitoring (and in some cases, near real time reporting) is not meant to be a substitute for in-depth, specific compound, analytical testing. Instead, the real-time surrogate monitoring is complementary to the COGCC-mandated groundwater testing before and after drilling new wells. Since the real-time monitoring will be correlated with this baseline testing, any change from these baseline conditions would trigger an alert and the CSU project team along with COGCC would further investigate the intensity and source of contamination for a more definitive assessment of the situation.