Potomac Submerged Channel Intake Environmental Assessment and Assessment of Effect, July 2016

You are invited to review the "Potomac Submerged Channel Intake Environmental Assessment and Assessment of Effect, July 2016."

Washington Suburban Sanitary Commission (WSSC) proposes to construct a new offshore submerged channel intake in the Potomac River for water supply at its Potomac Water Filtration Plant (WFP). The project would involve construction activities and the location of permanent WFP structures within the C&O Canal NHP. The purpose of the federal action is to respond to WSSC's proposal considering the purpose and resources of C&O Canal NHP, as expressed in statute, regulation, policy, and the NPS objectives in taking action.

There are four alternatives evaluated in the EA: the no-action alternative and three action alternatives. Under all action alternatives, the new intake and intake shaft would be constructed southwest of the existing intake facility using the drill and blast method. A boat ramp, parking area, and permanent access road would be constructed to provide access to the intake for maintenance. Cofferdams would be needed in the river for construction of the intake shaft and the boat ramp.

Under alternative 1, no-action, long-term adverse impacts on soils/geology, water resources, wetlands, floodplains, scenic resources, and visitor use and experience have resulted from the existing Potomac WFP. Alternative 2, the preferred alternative, would have long-term adverse impacts on geology and soils/sediment, water resources, wetlands, floodplains, vegetation, wildlife, special-status plant species, cultural resources, scenic resources, and visitor use and experience as a result of construction and operation activities. Impacts from alternative 3 would be similar to those of alternative 2, except the impact area of riverine systems (Potomac River), floodplains, and aquatic wildlife would be larger compared to alternative 2; however this increase in area impacted would not increase the impact intensity to these resources. In addition, impacts on visitor experience would be greater under this alternative due to surface blasting associated with trenching construction, which creates louder and more intense noise. Impacts from alternative 4 would be the same as those under alternative 2. Although some of the project components have slightly different configurations, the construction methods under alternative 4 are similar to alternative 2. Since this alternative requires the temporary relocation of the towpath this would cause a greater impact on visitors, but is not expected to increase the impact intensity.

NPS and WSSC invite you to attend a public meeting on Thursday, July 14, 2016 from 7:00 to 9:00 pm at Potomac Community Library (Medium Room), 10101 Glenolden DR, Potomac, MD, 20854. The meeting will consist of a brief presentation and an open house format to provide you with opportunities to discuss your interests and concerns with NPS staff.

To submit a comment on the project, click the "Comment on Document" button to enter and submit your comments. You can also submit written comments by mailing them to the park at the address displayed below. Comments will only be accepted during the public review period which ends August 14, 2016. Comments must be submitted or be postmarked by midnight on August 14, 2016 to be considered. Please reference this project by name on all hardcopy correspondence. Mail hardcopy correspondence to Christopher J. Stubbs, Chief, Division of Resources Management, C&O Canal NHP, 1850 Dual Highway, Suite 100, Hagerstown, MD 21740.

Before including your address, phone number, e-mail address, or other personal identifying information in your comment, you should be aware that your entire comment - including your personal identifying information - may be made publicly available at any time. Although you can ask us in your correspondence to withhold your personal identifying information from public review, we cannot guarantee that we will be able to do so.

Document Content:

Submerged Intake EA July 2016.pdf   (7.1 MB, PDF file) Submerged Intake EA July 2016 Appendices.pdf   (6.2 MB, PDF file) Assessment of Effects Report June 2016.pdf   (3.5 MB, PDF file) Disclaimer: Links within the above document(s) were valid as of the date published. Note: Some of the files may be in PDF format and can be viewed using the Adobe Acrobat Reader software. You may download a free copy of from Adobe Systems.