On Friday, July 17, CALH representatives and experts were admitted to the proposed Pintail Landfill site for further scientific investigations. The main purpose of the trip was to check the water table elevations on-site. As part of the MSW landfill application process, applicants are required to measure the water table elevations over time. Pintail did this from July 2011 to July 2012, during the drought, and has proclaimed that they have measured the highest possible water table elevations during that period. They have also proclaimed in their application that there are no groundwater springs within a mile of the site. Friday’s inspections revealed otherwise.
Saturated conditions in the mid-southern portion of the site.
There are a total of 15 shallow, small diameter water wells on site, called piezometers, for the sole purpose of measuring the water table elevations. CALH experts measured water table elevations in all 15 piezometers that were higher than the highest elevations measured and reported by Pintail in their application. The average increase in elevation, or decrease in depth below the ground surface, was over five feet, with the greatest increase being almost 7 feet. This poses serious problems for Pintail, who attempted to design the depths of excavations for their landfill cells in some areas to within a foot of the highest measurements that they took. It now appears that large areas of the landfill liner will be submerged below the water table.
Groundwater spewing from a water table elevation measurement well.
CALH representative Rick Welch, who accompanied the experts on Friday, commented that this is very alarming and used the analogy that over time, as the water table rises and falls, the situation would be similar to taking a tea bag and dipping it in and out of a hot cup of water resulting in our groundwater become leachate tea. Furthermore, he said that the leachate collection system for the landfill was not designed to accommodate the influx of groundwater into the landfill. He also said that further analysis will need to be done but that he felt that the bottom elevations of the proposed storm water detention ponds could also possibly be below the current water table, providing a pathway for contaminated groundwater to seep into the detention ponds and flow freely to the nearby pristine creeks.
Algae and rust are indicators of how long this well has been flowing.
But even more alarming was that one of the piezometers on the southern part of the landfill footprint was actually spewing groundwater as the team approached. CALH’s experts all indicated that in over 35 years each of doing this type of work, they had never seen a piezometer in artesian conditions where groundwater was actively flowing from one. A review of the drilling logs indicated that it was likely that groundwater was seeping to the surface over a large area and feeding the wetlands in the southern portion of the site.
Replacing the 2 inch PVC cap which had been pushed off the well casing by the flow of water.
This groundwater/surface water interaction poses not only a hazard to water wells in the area but poses serious risk of surface water contamination in Clear Creek and its tributaries. The overall increase in the height of the water table and active springs on-site are recent findings that will be added to other compelling expert testimony and evidence to be presented at the Contested Case Hearing scheduled to begin on November 2, 2015. Meanwhile, CALH is holding ‘We Stand United 3’, a dinner and auction event, this Saturday, July 25, to raise funds to finance the case. Information on CALH and its activities can be found at StopHwy6Landfill.com.
Measuring the height of the stream of groundwater spewing from the PVC cap air vent hole.