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Closure of boreholes at residual pollution sites


Mets Image: Kati Raudsaar

The aim of the project is to close 76 monitoring wells that have become devoid of purpose at residual pollution sites, and to close an exploratory borehole at the Abroi property in Ulvi village, Vinni Rural Municipality.

Monitoring wells have been set up at residual pollution sites to take groundwater samples and assess the remediation of the site. Monitoring wells have no purpose at sites that have been remediated and have exceeded their warranty period, where monitoring is no longer performed.

Over time, the structure of a monitoring borehole weakens, boreholes become overgrown and forgotten, and are also damaged by forestry and similar works. Damaged monitoring boreholes are potential pollution channels, through which hazardous substances can enter groundwater. This is why boreholes must be properly closed.

In 2019, the Ministry of the Environment commissioned 80 monitoring borehole closure projects at residual pollution sites. As a result of the work, boreholes not included in the construction register were entered into the register, and a technical solution for the closure was designed and agreed with the local governments. Four boreholes had been completely destroyed and could not be found in the wild. 76 boreholes require proper closure according to a closure plan agreed with the local government.

The project will be fully funded in 2022.