Summary of Most Recent Developments

On May 7th, 2008, Constellation Energy filed with MDE a report detailing the results of ongoing evaluation of groundwater at and adjacent to the BBSS site, and recommendations for remediation. The report includes the following proposals:

• Developing a site-specific groundwater model.
• Developing a list of potential alternatives for site remediation.
• Consideration of the use of source controls, such as minimizing the potential for water to come in contact with the ash, and the use of plume controls, such as collecting groundwater for treatment.
• Using the groundwater model developed for the site to evaluate the likely effectiveness of viable remediation options.

One of the key findings of our evaluation at the site is that remediation efforts Constellation Energy has taken since 2004 have been effective in preventing migration of the groundwater plume from Turner pit. An additional finding is that the Waugh Chapel plume will be captured at the Turner pit groundwater collection point after it passes the Summerfield Rd. area.

The filing recommends two different remediation options, both of which are aimed at capturing the plume and preventing future ash impacts. Both options would attain the groundwater remediation goals specified in the consent agreement. The difference between the two options is that one is a phased approach that targets suspected trouble areas, while the other a more conservative strategy with more immediate and comprehensive implementation.

Option 1 includes:

• A development cap (buildings, pavement, improved cap in unpaved areas) at Turner pit.
• Focused source control at Waugh Chapel pit using lined swales to the north and west of the ash fill, and relocation or lining of the pond near the ash fill, to manage storm water and water from the sand washing operation. This approach targets areas that are believed to be the primary entry points for water into the ash fill.
• Continued use of the existing five well collection system with plans for a sixth recovery well.
• Periodic review of groundwater quality, and refinement of the groundwater model to evaluate the effectiveness of the focused source control and to determine whether additional actions are appropriate.

Option 2 includes:

• A development cap (buildings, pavement, improved cap in unpaved areas) at Turner Pit.
• Focused source control at Waugh Chapel pit using lined swales to the north and west of the ash fill, and relocation or lining of the pond near the ash fill, to manage storm water and water from the sand washing operation. This approach targets areas that are believed to be the primary entry points for water into the ash fill.
• Enhanced cap at Waugh Chapel pit.
• Continued use of the existing five well collection system with plans for a sixth recovery well.
• Installed infrastructure (wells, piping, etc.) for an enhanced groundwater recovery system, with details to be determined in the design phase of the project.
• Periodic groundwater quality evaluations to determine if and when expansion of the groundwater collection zone, through the use of the installed infrastructure, is needed for more efficient capture of the plume.

Implementation of a remediation plan will begin once MDE approves a remedial strategy.