There are 487 onshore oil and gas fields in California; these were classified as high, medium, and low priority for detailed study as part of the COGG program based on the intensity of petroleum resource development and proximity to groundwater resources (Davis and others, 2018). Each year, a new set of high priority fields is selected based on feedback from the State Water Board and Regional Boards. The map shows what kind of work has been done in which fields to date.

Oil and Gas Fields

Work beginning in 2016

Work beginning in 2017

Work beginning in 2018

Work beginning in 2019

Work beginning in 2020

Work beginning in 2021

Fields not yet sampled or analyzed

high priority fields (Davis and others, 2018)

moderate and low priority fields (Davis and others, 2018)

Black border denotes protected groundwater mapped from 2015-2018 using existing water sample data (Metzger and Landon, 2018)