Commission uses HOBO data logger to collect data before gas tapping

Hydraulic fracturing, or fracking, is the proposed method for extracting natural gas from the bedrock in the Delaware River Basin. The process involves drilling wells to reach deep shale formations and injecting water and chemicals into the strata to release the gas. The flowback water from this process contains potentially toxic chemicals, and the wastewater is usually stored at the well site for later treatment or disposal.

Fracking is a controversial topic. Many environmentalists fear that the process could have a negative ecological impact. Others, however, see the creation of a quarter of a million jobs, the possibility of supplying up to 14 years of the country's natural gas consumption and the added benefit of producing a fuel that burns cleaner than coal or oil.

Comprehensive monitoring is key to understanding the environmental impacts that could be caused by hydraulic fracturing. Therefore, the DRBC has implemented a new monitoring program that examines various parameters typically affected by natural gas development, including the electrical conductivity of river water, which can be an indicator of contamination. In August 2009, for example, high conductivity levels were detected in Dunkard Creek in West Virginia, and over the next month nearly all aquatic species along a 35-mile stretch of the waterway had disappeared, possibly due to nearby hydraulic fracking activities.

Use of the data logger

As part of the Monitoring for Natural Gas Development program, the DRBC's Monitoring, Modeling & Assessment department installed HOBO® U24 conductivity and temperature loggers in the Delaware and Lackawaxen rivers, as well as two other streams in Pennsylvania where drilling is likely to occur first. To install the loggers, shallow concrete bases were constructed by pouring concrete into a coaster. Two short aluminum pipes protrude from the concrete base, and a horizontal PVC pipe with holes is attached to the base to hold the sensor, which is secured with cable ties. Placing the sensor in the PVC pipe minimizes bubbles and sediment that could otherwise build up on the sensor.

Before deploying the loggers, DRBC staff tested the accuracy of the devices against other meters, measuring a variety of low and high conductivity waters, such as ultra-pure lab water, tap water and salt water, and found that they matched. Staff regularly pick up the loggers and download the readings using a waterproof HOBO data shuttle, which, as John Yagecic, environmental engineer and DRBC department head, notes, "...allows us to easily download the data in the field." Once the data has been downloaded, the loggers are cleaned with distilled water and deployed again.

The advantages of HOBO data loggers

The DRBC chose HOBO data loggers because they needed equipment that could be set up quickly and guaranteed a smooth start to the project. Time was of the essence as it was not known when the gas companies would start drilling, and without extensive water quality data prior to drilling, the extent of the changes in the rivers would forever remain a mystery.

Data loggers that can withstand harsh weather conditions were also a requirement for the monitoring program, as the logger deployment sites are exposed to cold temperatures and periodic high water levels. The DRBC was pleased to learn that HOBO data loggers deployed in similar conditions were not affected by Hurricane Irene, which struck the Northeast in the summer of 2011. Yagecic is also pleased to report that since their deployment in January 2011, the loggers have continued to tolerate downstream moving debris and have proven to be a cost-effective solution for use in high-risk situations.

By defining the range and variability of specific conductivity measurements prior to natural gas drilling, this monitoring program will help the DRBC protect valuable water resources in the Delaware River Basin.