Wellhead Protection Program Monitoring:

Based on the amount of time it takes a drop of water to travel from its source, through the Mint Farm aquifer and to the City's wellfield, a boundary was created to define the limits of the aquifer and establish an area for wellhead protection. 


As part of its Wellhead Protection Program, the City collects groundwater samples from deep sentinel wells surrounding the Mint Farm wellfield every six months to look for changes in water quality. For a summary report and laboratory results for each sampling event, click on the following links:

Sampling for wellhead protection uses a series of sentinel wells strategically located around the perimeter of the Mint Farm wellfield to establish a line of defense for advance warning of potential migration of contaminants from nearby industrial and commercial sources.

WHPA Well Map

  • Deep Monitoring Wells Construction Well Logs - A detailed record of the geologic formation of deep monitoring wells DW-1 through DW-9 based on visual inspection of the cuttings produced during drilling and physical measurement made by instruments lowered into the hole.
  • Monitoring Well Sampling Program - An itemized list of routine DOH test panels and special interest analytes tested for during semi-annual sampling events including recommended testing frequency, EPA test method and estimated laboratory costs. 
  • Wellhead Protection Program - The WHPP was developed to protect the groundwater source and comply with WAC 246-290-135 (3). The Department of Health approved the plan in March 2010 and it was incorporated in the City's 2012 Water Master Plan Update.
  • Water Supply Protection Ordinance No. 3209 - This ordinance supplements the WHPP to minimize the risk of contamination and provide a means of enforcement, while still allowing economic development which does not pose unreasonable risk to the aquifer. Staff continues to work with Cowlitz and Columbia counties to adopt similar ordinances to protect the groundwater supply.
Last updated: 5/24/2018 2:48:54 PM