MDE Reviews Exelon Conowingo Application, Dam Included in Latest Bay Model

The Maryland Department of the Environment (MDE) has started the formal review process for reviewing Exelon’s application for Clean Water Act Section 401 Water Quality Certification for the Conowingo Hydroelectric Project. Exelon must obtain a certification from MDE prior to getting a new license from the Federal Energy Regulatory Commission. From a MDE Acknowledgment Letter to Exelon (2017-06-23):

MDE plans to place your application on public notice within the next 2 weeks and expects to establish a 30 day public comment period. The public notice will provide a brief description of the proposed project; provide instructions for submission of written comments; and specify the expiration date for the opportunity to comment. After the end of this initial public comment period, MDE plans to provide notice in the Maryland Register of its intent to hold a public hearing on your application. At this time, MDE expects that the public hearing will occur in the fall of 2017. MDE may re-open the public comment period in the event that additional information becomes available which MDE determines should be subject to review and comment. …

MDE will identify all applicable water quality standards and requirements and utilize data, modeling, and further scientific analyses along with the materials provided in your application, and information provided in public comments to determine whether the operation of and discharges from the Conowingo Hydroelectric Project will comply with all applicable Maryland water quality standards and requirements, including those downstream, in the Chesapeake Bay. MDE will undertake this review in coordination with the Maryland Department of Natural Resources as well as other governmental agencies and organizations as appropriate. Should Exelon choose to supplement its application, for example, to address any additional impacts not yet addressed in its applications, MDE will publish the amendments to the application and re-open the public comment period as may be appropriate.

While the sediment and phosphorus pollution generated by the Conowingo Dam and Susquehanna River does not affect every local waterway or Bay tributary, its effect on the main stem of the Bay can be significant, especially during a major storm event. In acknowledgment of the dam’s effect, the latest version of the Bay Model (Phase 6) will incorporate anticipated loading by the Conowingo. Based on preliminary Phase 6 Model results, the Conowingo will add 1-3% more to predicted non-attainment numbers and add 2 million additional pounds of phosphorus into the Bay that must be addressed. A draft EPA consultant analysis has proposed several scenarios for addressing the Conowingo issue. Under at least one of these scenarios, Maryland could see a significant amount of phosphorus added to its target goal under the Bay Total Maximum Daily Load (TMDL) and be faced with hundreds of millions of dollars in additional costs.

MDE’s public comment period runs through August 9. See the link below for submission instructions.

Useful Links

MDE Conowingo Application Public Notice & Request for Comments (2017-07-10)

Prior Conduit Street Coverage of the Conowingo Dam