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Midcounty Corridor
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Midcounty Corridor Study


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  1. August 2015 Midcounty Corridor Study Update
  2. April 7, 2015 Statement of Montgomery County Department of Transportation Acting Director Al Roshdieh
  3. March 2015 Draft Preferred Alternative/Conceptual Mitigation Report (PA/CM)
  4. MCDOT February 4, 2014 Responses to Comments from USACE/MDE/EPA/the City of Gaithersburg
  5. MDE December 12, 2013 Information Request Letter
  6. Planning Board November 25, 2013 Recommendation Letter
  7. USACE November 19, 2013 Information Request Letter
  8. EPA August 20, 2013 Comment Letter
  9. Transcript for August 7, 2013 USACE/MDE Joint Public Hearing
  10. Public Notice for August 7, 2013 USACE/MDE Joint Public Hearing
  11. The City of Gaithersburg July 17, 2013 Comment Letter
  12. May 2013 Draft Environmental Effects Report (EER)
  13. June 2012 Midcounty Corridor Study Video
  14. June 2012 Midcounty Corridor Study Traffic Report
  15. November 2010 Alternative Retained for Detailed Study (ARDS) Map
  16. November 2010 Modified ARDS Recommendations
  17. June 2010 ARDS Recommendations
  18. January 2007 Purpose and Need
  19. Contact Us/Comments


Environmental Inventory

Environmental Process
Environmental Inventory

Environmental Process

The National Environmental Policy Act (NEPA) of 1969 requires that a project using federal funds or seeking approval from a federal agency analyze a range of alternatives and consider the effects on the natural, cultural, and social environments within the project area.  While the Midcounty Corridor Study is going to be funded through the County, the project will require a permit from the US Army Corp of Engineers (USACE) to comply with the Clean Water Act.  Therefore, the USACE is the lead federal agency for the project and the US Environmental Protection Agency (USEPA) and the Maryland Department of Environment (MDE) are concurring agencies on the project.

The NEPA process serves as a guide during the development of the project for the management, deliverables, and concurrence points.  The NEPA process is outlined in the following steps.

STEP 1: Purpose and Need
Identify the purpose and needs for the study.  The January 2007 Purpose and Need Statement documents the need for the Midcounty Corridor Study. 

STEP 2: Environmental Inventory and Range of Preliminary Alternatives
Conduct an environmental inventory of existing conditions and identify a range of preliminary alternatives. An inventory of resources includes existing and known wetlands and streams, historic resources, community facilities, and neighborhoods.  The results of this step were presented at a Public Workshop on December 12, 2007.

STEP 3: Identify Alternatives Retained for Detailed Study                                         
Identify the alternatives retained.  Further analysis is done on these alternatives including revisions to the alignments and engineering details to better serve the project Purpose and Need and avoid or minimize direct impacts (physical and noise impacts) to social, cultural, and natural resources.  This step has been completed and concurrence in the Final ARDS has been received from environmental agencies. For more details, see the Alternatives tab.

STEP 4: Detailed Study and Draft Environmental Document
Proceed with detailed engineering and environmental studies for the retained alternatives and options and refine the alternatives and options to make them as socially, environmentally, and operationally beneficial as possible.  Cost estimates will be developed and detailed impacts to traffic, properties, and social, economic, cultural and natural resources will be evaluated.  The result of the detailed study will be documented in a Draft Environmental Document for agency review and concurrence.  The Draft Environmental Effects Report was published in May 2013.

STEP 5: Public Hearing
Draft Environmental Document will be published and made available for public feedback, and public hearing will be held for public testimony.  The USACE/MDE Joint Public Hearing was conducted on August 7, 2013.

STEP 6: Identify Preferred Alternative and the Preferred Alternative/Conceptual Mitigation Report
After a public hearing on the Draft Environmental Document, MCDOT will identify a preferred alternative and refine this alignment based on public and agency comments to further avoid, minimize, and mitigate impacts. These refinements will be documented in the Preferred Alternative/Conceptual Mitigation Report (PA/CM).  The County, State and Federal Agencies will make their final review and approval of the Preferred Alternative.  This step is expected to be completed in late 2016.

This concludes Midcounty Corridor Study (MCS).

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Environmental Inventory

The environmental inventory includes identifying known social, natural, and cultural resources using GIS databases from county, state, and federal agencies.  These mapped resources are verified with field surveys. The inventoried resources include but are not limited to:

Natural Resources: wetlands, streams, floodplains, forests, and farmlands;
Cultural Resources: historic properties and anticipated prehistoric and historic archeological sites;
Community Resources: parks, schools, churches, and properties affected; and
Other Resources: hazardous materials, noise, and air quality.

A more detailed environmental analysis will be conducted concurrently with the detailed engineering of the retained alternatives which focuses on ways to avoid, minimize, and mitigate resource impacts.  The detailed environmental analysis is updated and supplemented with field-gathered data.  The environmental analysis for each alternative will be documented in the Draft and Final Environmental Documents.

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