Baltimore-Washington Parkway Widening Feasibility Study

Baltimore-Washington Parkway Widening Feasibility StudyEnvironmental EffectsIn Maryland, stream and wetland mitigation are typically permit conditions related to MDE and/or U.S.Army Corps of Engineers authorizations or permits. Mitigation requirements will depend on the qualityand quantity of impacts. The Compensatory Mitigation for Losses of Aquatic Resources Final Rule (40CFR 230) governs compensatory mitigation for activities authorized by MDSPGP-3 or Corps IndividualPermits (i.e., wetland and waterway impacts). The amount of mitigation required is determined byfunctional or condition assessment or a suitable metric (minimum 1:1 acreage or linear feetcompensation) and should be commensurate with project impacts.7.2.3KnownCulturalResourcesEffectsCultural resources in this planning context are characterized as historic structures, districts, landmarksand landscapes as well as archeological (subsurface) artifact sites. Section 106 of the National HistoricPreservation Act of 1966 (as amended) requires that historic properties be considered while planningand executing an undertaking requiring Federal permits or funds. Generally, historic properties arethose that are more than 50 years of age, and that are listed in or eligible for listing in the NRHP.Potential direct effects to known historic properties would be unavoidable under any of the wideningoptions. As reflected in the table below, the inside widening options encounter fewer known historicproperties than the outside widening options.Potential Cultural Resources ImpactsPotential Effect AASHTO / SHA NPSWidening Options Outside Inside Outside InsideKnown Historic Properties(each)4 2 4 2Any of the four build options would have direct effects on the NRHP-listed B-W Parkway in the form oflane and shoulder additions, interchange and ramp modifications, mature tree and landscaping removalor alteration, alterations to vistas, and overall change in historic character. Similarly, any of the fourbuild options could affect the National Register-eligible BARC. The two outside widening options couldalso directly affect the National Register-listed Greenbelt Historic District and the National RegistereligibleD.C. Children’s Center - Forest Haven District (facility closed).Although a detailed evaluation of archeological potential is beyond the scope of this preliminaryanalysis, there are portions of the B-W Parkway alignment that can be identified as having higherpotential for archeological sites, based on a variety of environmental and land-use factors. The originalconstruction of the Parkway and intersecting roadway interchanges would have resulted in thedisturbance of many of the landforms the alignment crosses. However, as the design was predicated onthe preservation of natural topography and vegetation, the level of disturbance will be variable and65 November 2012