Summary of Most Recent Developments
On September 17, 2010, Constellation Energy provided to MDE a revised remediation proposal, (supplementing its May, 2008, proposal) that would include the following elements:
- The development cap would be installed as proposed at Turner Pit.
- An enhanced cap for Waugh Chapel Pit, consisting of (from top down) 6 inches of topsoil; a 24‐inch rooting layer; a geocomposite or 6‐inch sand drainage layer; and a clay, GCL, and/or synthetic barrier layer.
- Extension of the existing cap at Waugh Chapel Pit to limit vertical infiltration in swales outside the focused source control area.
- Focused source control to reduce lateral infiltration into Waugh Chapel Pit. [Note that since the submittal of the original plan, plans have been in progress to accomplish this goal in a comprehensive manner by eliminating the source of lateral infiltration by relocation of the existing sediment pond. The basis for this decision was that the elimination of a source of water is far more effective than building a barrier to keep it out.]
- The current 6‐well groundwater recovery system, with infrastructure to expand the system if needed. Recovered groundwater will continue to be treated using the existing treatment system.
- Institutional controls for the ash fill areas and continued groundwater monitoring.
In addition to these elements, this revised remediation plan builds on the proposed expanded infrastructure by adding to the locations for groundwater extraction. It incorporates the following expansion (for use under a phased pumping strategy):
- Two additional extraction wells, RW‐7 and RW‐8, are proposed along Route 3 northeast of the current Brickhead Road and the existing line of extraction wells RW‐1 through RW‐6.
- Two additional extraction wells, RW‐9, RW‐10 and existing well RW‐11 along the east side of Waugh Chapel Pit in the vicinity of monitoring well MW‐21.
This proposed remedy is predicted to achieve steady progress toward the remediation goals and prevent adverse impact to human health and the environment. Following MDE approval of a remedial alternative, detailed planning and engineering will proceed.