THE DIRT: What are bollards and what do they do?

If you've spent time exploring the Coeur d'Alene Basin, you've probably noticed bright yellow posts scattered throughout the landscape. They can be found near repositories, along roadsides, and at various cleanup sites. While they may not look like much, these yellow markers represent an important part of the long-term effort to understand contamination and measure the success of certain cleanup activities. 

The yellow posts or markers are called “bollards.” Many of these bollards identify and protect groundwater monitoring wells from damage from vehicles and heavy equipment. The wells are installed during site investigations and to conduct long-term monitoring of groundwater flow direction and groundwater quality. Before a well is installed, crews drill deep into the ground to collect soil samples and characterize subsurface contamination. These investigations help scientists determine the nature and extent of metals contamination below the surface and identify areas that may require remediation. 

Once drilling is complete, the boreholes are often converted into monitoring wells. A typical monitoring well consists of a PVC pipe with specially designed screened intervals that allow groundwater to enter the well at specific depths. The PVC pipe is placed into the borehole. The open space between the PVC Pipe and the sides of the borehole is filled by carefully placing sand and sealing materials that ensure samples accurately represent groundwater conditions at the target depth. 

These wells serve several important purposes. They allow scientists to measure groundwater elevations which are used to determine which direction the groundwater is moving underground and collect water samples to determine whether metals contamination is present in the groundwater. This information is critical because groundwater is the main source of drinking water in Idaho and can discharge into streams, rivers, and wetlands, potentially contributing to surface water contamination. Understanding these connections helps project managers design remedies that not only remove contaminated soil but also reduce ongoing groundwater contamination. 

The monitoring wells also provide valuable information about the effectiveness of cleanup projects. Permanent monitoring locations have been established around repositories, the Central Impoundment Area (CIA), and other remediation sites throughout the Basin. 

One recent success story comes from the groundwater collection system at the CIA. Monitoring data has shown improvements in water quality downstream of the collection system and Central Treatment Plant, providing evidence that the remedy is working as intended. These results help confirm that investments in remediation are reducing the movement of contamination into nearby waterways. 

While a yellow bollard may seem insignificant, it marks a critical piece of a much larger monitoring network. Together, groundwater wells, surface water monitoring stations, and sediment sampling programs help scientists track contamination, evaluate cleanup effectiveness, and understand what is moving downstream toward Lake Coeur d'Alene. Organizations including EPA, Idaho Department of Environmental Quality (DEQ), the Coeur d'Alene Trust, and the U.S. Geological Survey all contribute to this monitoring effort. The data collected at these locations provides the information needed to make informed decisions and ensures that cleanup efforts continue to protect human health and the environment for generations to come.

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The Dirt is a series of informative articles focused on all aspects of cleanup efforts associated with the Bunker Hill Superfund Site. Our goal is to promote community awareness of contamination issues, to provide tools for protecting public health, and to keep the community informed of current and future cleanup projects. The Dirt is a group of committed and local experts from multiple agencies, including the Basin Environmental Improvement Project Commission, Panhandle Health District, Shoshone County, Silver Valley Economic Development Corporation and the Idaho Department of Environmental Quality.