Climate-Control Rehabilitation of Boswell's Tavern

In consultation with its Section-106 advisor for archeology, the NPS proposes a "No Adverse Effect" designation (thus approval) of rehabilitation proposed for Boswell's Tavern by its owners under the terms of a conservation easement. The 2-story, frame structure is situated in and a contributing resource to the Green Springs National Historic Landmark District (Figs. 1-2 illustration packet). The National Register stipulates "18th Century" for the tavern's period of significance. The work, which would not entail the installation of above-ground features or structures, would consist of the four-step installation of geothermal wells and connector pipes in the front yard of the tavern (Fig. 4): (1) Excavate a trench 18 inches wide by 48 inches deep along 55 feet of the centerline of the existing, front gravel driveway to the south of the building. (2) Drill five wells at regular intervals in the bottom of the trench, each well to a bore of six inches in diameter and a depth of about 300 feet. (3) Excavate a trench 18 inches wide by 48 inches deep and 27 feet long, connecting the westernmost well (and the western end of another pipe connecting all five wells) to the south, cellar wall of the tavern building. (4) Drill two four-inch-diameter holes through tavern's foundation-wall at point of contact with connector-trench, 48 inches below surface. This will allow ingress of connector-pipe to HVAC unit in basement. The following 4 measures (A-D) are proposed to minimize impacts to historic resources: (A) The property owners are withdrawing their initial, less-expensive proposal for a geothermal component, a "loop-field" trench system in the rear (north) yard of the tavern building (Fig. 5). That would have required excavation of trenches measuring more than 1,600 feet. Agreeing with NPS concerns about a high potential for impacts to the archaeological remains of former dependencies and other potentially significant features in the rear of the building, and with a large amount of excavation, the owners have instead proposed a geothermal-well system on the opposite, front side of the tavern, necessitating trenches measuring less than 85 feet. (B) The switch to the front side for the geothermal component—and specifically to locations under the front, gravel driveway—is also intended to allow for ingress and egress of excavation equipment along the driveway's hard surface and its hard-packed fringes to further minimize potential impacts from such equipment. (C) In consultation with the Section-106 advisor for archeology, NPS is proposing a staged approach to the excavation of the two trenches that would allow for avoidance of significant artifact deposits or subsurface features if encountered. All excavation would be monitored by a qualified archaeologist. The trenches would be excavated either manually or using a backhoe with a smooth bucket, and only to the depth of the culturally sterile subsoil. The archaeologist would then examine the surface of the subsoil for the presence of cultural features. If none is identified, then the excavation of the well-openings trench may continue to the required depth. (As the wells will be drilled within this trench, no further monitoring of the drilling would be necessary.) This would be repeated for the second trench. Should potentially significant artifact deposits or subsurface features be identified, then the trenching would be diverted to avoid them, if possible. If avoidance is not feasible, then the archaeologist should consult with the NPS and VDHR to determine what further investigation and/or evaluation may be required. The archaeologist should map and photograph the trenches, and record the stratigraphic profiles for future reference. Finally, should any archaeological remains be identified (even if they are to be avoided), the archaeological component of this resource should be inventoried with the VDHR in VCRIS. (D) Remove from property earth from trenches and wells.

Contact Information

Noel Harrison
noel_harrison@nps.gov