State’s Selected Cleanup Plan to Move Forward at Colstrip Ash Ponds
Talen Montana Will Not Pursue Alternative Remedy at the Units 1&2 Stage One Evaporation Pond and Stage Two Evaporation Pond Area
HELENA— The Montana Department of Environmental Quality (DEQ) has received notice from Talen Montana, LLC, the operator of the Colstrip Steam Electric Station, that the company will not pursue an alternative cleanup strategy for the Colstrip coal ash pond cleanup at the Units 1&2 Stage One Evaporation Pond/Stage Two Evaporation Pond (SOEP/STEP) area. The notice means Talen will continue to move forward with DEQ’s selected cleanup plan to address groundwater contamination resulting from leaking ash ponds at the plant.
“DEQ maintains the best solution for addressing contamination in these coal ash ponds is to remove the coal ash and place it in a new lined landfill,” said DEQ Director Chris Dorrington. “Talen Montana’s decision to not pursue a Request to Amend the Remedy is welcome news and will allow us to stay focused on implementing DEQ’s selected method of cleanup and move forward without delay. Montanans now have assurance that will happen.”
The Units 1&2 SOEP/STEP area includes multiple ponds and cells located approximately 2 miles northwest of the Colstrip Power Plant that received coal ash waste, including, bottom ash and fly ash, from Units 1&2 during power plant operations from 1976 through 2020. Enforcement action taken by DEQ in 2012 to address groundwater contamination resulted in an Administrative Order on Consent (AOC) that requires investigations and remediation plans to address three distinct areas of contamination at the site, including the Units 1&2 SOEP/STEP area.
Additional Background
During the process to evaluate and select cleanup remedies under the AOC, DEQ selected a remedy for the Units 1&2 SOEP/STEP area called Alternative 10. DEQ’s selected remedy for the Units 1&2 SOEP/STEP area would clean up contamination through excavation of coal ash from the existing pond area and placement of the material in a new, lined landfill on Talen Montana’s property, located above the water table and outside the footprint of the current coal ash ponds. The selected remedy includes additional dewatering components and a flushing/capture well network to further address groundwater contamination.
A settlement agreement reached in 2021 allowed Talen to continue to evaluate the feasibility and design of one alternative remedy called Alternative 11A, which would have addressed groundwater contamination while leaving the coal ash waste within the footprint of the existing Units 1&2 SOEP/STEP area. Talen notified DEQ this month that the company will cease its evaluation of Alternative 11A.
Since the settlement agreement, while concurrently evaluating the alternative remedy, Talen has maintained work on the design of the DEQ-selected remedy and has continued to implement approved interim cleanup components such as dewatering at several ash ponds and operation of a small-scale clean water flushing and groundwater capture system. Talen is on track to complete all requirements of the settlement and landfill construction is expected to begin in 2025.
For more information, on the remedy, the 2012 AOC and the 2021 settlement agreement, visit: https://deq.mt.gov/cleanupandrec/programs/colstrip
Tags: Cleanup, Colstrip and Press Release