Site Background
The community of Hinkley is located in the Mojave Desert approximately 14 miles northwest of Barstow, California. The climate and hydrogeology of the Hinkley Valley is characterized by the arid environment of the Mojave Desert, with rainfall averaging between 4 to 6 inches per year.
The Pacific Gas and Electric Company’s Hinkley Compressor Station is located in Hinkley, approximately one mile north of the Mojave River and 8 miles west of Barstow in San Bernardino County. The Station is used to compress natural gas for transportation through pipelines to Central and Northern California.
Between 1954 and 1964, hexavalent chromium in wastewater leached from unlined ponds to groundwater, about 80 feet below ground surface. Hexavalent chromium was then carried in groundwater in a generally northward direction. Hexavalent chromium in groundwater is presently detected above 3.1 parts per billion (ppb) in areas up to four miles north of the Compressor Station and almost two miles in width in the vicinity of Highway 58. Under orders by the California Regional Water Quality Control Board, Lahontan Region, PG&E continues to install monitoring wells to define the downgradient extent of the plume, and to implement cleanup actions to remove chromium from groundwater.
More information about the site can be found in the latest Lahontan Water Board Project Update.
Former Waste Pit Groundwater Investigation Related Documents
- 07/10/2014 – Water Board’s Response to CAC’s and IRP Manager’s Comment Letter
- 06/20/2014 – CAC’s and IRP Manager’s Comments Regarding the Water Board’s June 3rd Letter
- 06/03/2014 – Water Board’s Response to PG&E’s Technical Memo, Former Waste Pit Groundwater Investigation
- 05/01/2014 – PG&E’s Technical Discussion and Scope of Work to Evaluate Groundwater Quality in the Area of the Former Waste Pit
- 03/05/2014 – Waste Pit Investigative Order No. R6V-2014-0019
- 12/04/2013 – Closure Report for Debris Removal and Cleanup Western Excavation Site, Hinkley, California
Former Waste Pit Groundwater Investigation Photos
Hinkley Compressor Station – Source: Google Earth 
Source: Stantec. 2014. Technical Discussion and Scope of Work to Evaluate Groundwater Quality in the Former Waste Pit – Investigative Order R6V-2014-0019. May 1.