Edsel & Eleanor Ford House and Henry Ford Estate
NTH Consultants, Ltd.
Kathleen Stiso Mullins, Ph.D.,
Total NTH Budget:
NTH’s Value Added: NTH provided services to assist the Client’s understanding of the existing condition of the dam and ancillary components as well as historically appropriate repair approaches for a nearby failed wall on a site that is a designated National Historic Landmark in the National Register of Historic Places.
Henry Ford Estate Dam
Dam Inspection and Additional Evaluation
NTH was retained to perform an exploration of the dam located on the Middle Branch of the River Rouge at the historical Henry Ford Estate. Our services were part of the Due Diligence activities performed prior to the transfer of ownership of the site to a newly formed nonprofit organization for conservation of the estate. The study included review of previous Part 315 Dam Inspection Reports, visual review of the dam and ancillary components as well as the upstream and downstream shorelines. The project included providing consultations and recommendations to the client for various repairs to observed deficiencies in the shoreline adjacent to the dam. These deficiencies included a sinkhole that had formed behind the channel wall on one end of the dam and a slope failure that damaged a portion of the channel wall upstream from the dam.
During the Due Diligence activities, NTH representatives made multiple visits to the site over the period from May 2011 through May 2013 to observe the conditions of the dam and nearby site features, including during and following flood conditions of the Rouge River. For study of the behavior and performance of the dam, NTH personnel collected photographic documentation of the overall dam as well as specific items of interest, such as the sinkhole, during these visits. Doing so allowed for evaluating the progression of deterioration, where occurring, so as to provide a basis for evaluating the severity distress and prioritizing the required repairs. NTH suggested a conceptual repair approach for the sinkhole that would be feasible to implement in limited available working space.
Prior to our involvement with the Due Diligence activities, a slope failure occurred in April 2011 along the left (looking downstream) bank of the Rouge River. This slope failure was located appreciably upstream of the existing Henry Ford Estate dam and NTH established that it did not directly affect the stability of the dam. The failure was indicated by a curved scarp that crossed a footpath located near the top of the slope between the water’s edge and the back lawn of the estate. A portion of the limestone retaining wall that defined the river channel in this portion of the estate grounds was lost into the river and the adjacent portions of the wall were damaged.
After considering multiple options, NTH recommended an approach for slope repair and reconstruction of the wall that incorporated a mechanically stabilized segmental block retaining wall (SRW) behind the limestone retaining wall to help stabilize the slope, a row of permanent sheetpiles installed proximate to the limestone wall and SRW also to help stabilize the slope and preclude erosion of soils supporting the walls, riprap placed on the slope in front of the wall to protect the underwater slope from further erosion, and a temporary sheetpile cofferdam to facilitate restoration of the slope below the river level.
NTH recommended this approach as it was considered to be technically feasible and could maintain the overall appearance of the original wall design and be visually integrated with the existing wall away from the failure area. NTH also determined that this could be implemented in a manner consistent with the applicable historic preservation guidelines for the estate.