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Groundwater Advisory Unit

The Groundwater Advisory Unit (GAU) provides groundwater protection determination letters.  There are three types of letters:
Groundwater Protection Determination

  • This type of groundwater protection determination letter, where possible, provides top and bottom of fresh water (less than 1,000 mg/L total dissolved solids (TDS)) and
  • Base of usable-quality groundwater (3,000 mg/L TDS and other waters known to be used or identified as sources of desalinization water).
  • This type of groundwater protection determination is used for new drills, cathodic protection, re-entry, well integrity test, microseismic boreholes, injection into a producing zone, plug and abandon,  and conversion of an oil and gas well to a water well.

Groundwater Protection Determination for Saltwater Disposal Wells

  • This type of groundwater protection determination letter provides the base of the underground source of drinking water (less than 10,000 mg/L TDS) and
  • Verifies geologic isolation from the base of usable-quality groundwater.

Groundwater Protection Determination for Seismic Survey

This type of groundwater protection determination letter provides a range of depths for the base of usable-quality groundwater across the seismic survey.