Region I Mitigation Division

FEMA's Environmental Planning and Historic Preservation (EHP) Program: Jack Sullivan, Environmental Officer

FEMA Region I - Historic Preservation Staff in Action

A view looking west towards the downstream side of the Silvermine Avenue Retaining Wall and Culvert.

Learn more about FEMA's Environmental Planning and Historic Preservation (EHP) Program

FEMA-funded projects may affect significant historic properties that are eligible for listing or actually listed on the National Register of Historic Places.  If there is an adverse effect from the action, the regulations related to the National Historic Preservation Act call for consultation between FEMA and the State Historic Preservation Office (SHPO) to discuss what mitigation measures might be appropriate to counter such effects.  The following article from the Society for Industrial Archaeology Newsletter was deemed appropriate mitigation by the FEMA Environmental Historic Preservation Team Leader for DR-1700-CT and the SHPO.  The article is related to the repair of a historic roadway in Norwalk, Conn. funded during the disaster declaration which resulted from severe storms and flooding in Connecticut in April, 2007.

Silvermine Avenue Retaining Wall and Culvert, Norwalk, Connecticut

Statement of Purpose

The Federal Emergency Management Agency’s (FEMA) Public Assistance Program (PA) provided funding to restore damaged Silvermine Avenue Retaining Wall and Culvert between Comstock Hill Avenue and Belair Road, Norwalk, Connecticut , to their pre-disaster condition or to a condition sufficient to perform their pre-disaster functions.  As a result of heavy rains and widespread flooding during the incident period between April 15 and April 27, 2007, a Presidential Disaster, referenced as DR-1700-CT, was declared which made PA funding available to Fairfield County.

During the incident period, heavy rain scoured a section of the Silvermine Avenue Retaining Wall and Culvert in Norwalk, Connecticut.  The scour resulted in bulging on the northern section of the downstream side of the retaining wall as well as damage to the road surface, in an area estimated to be 60 feet (ft) long x 4 ft wide x 10 ft deep.  The proposed scope of work for this project is to dismantle the affected portion of the stone wall and rebuild the damaged portion with the same stone to the same dimensions.  The affected portion of the road will also be repaired.

Per Section 106 of the National Historic Preservation Act, FEMA consulted with the Connecticut State Historic Preservation Office (SHPO) about this project.  The Silvermine Avenue Retaining Wall and Culvert has been determined to be eligible for the National Register of Historic Places.  It has been determined to have significance under Criteria A, as it is related to the history of the transportation network of the community of Silvermine.  Silvermine Avenue was a key road to the development of this area, and this structure, which encompasses the raised roadbed, the culvert, and the retaining wall, was an integral part of that road.  This structure also has significance under Criteria C.  Many early roads have been heavily modified and no longer retain their original methods of construction.  This structure exemplifies an early example of road engineering.

This documentation study is being undertaken by FEMA as part of a consensus determination with the SHPO of No Adverse Effects to the Silvermine Avenue Retaining Wall and Culvert. 

At present, the Silvermine Avenue Retaining Wall and Culvert serves to carry traffic on Silvermine Avenue over Silvermine Brook.  The proposed actions will not change this function.

History of the Silvermine Area

The Silvermine Community Association defines Silvermine as an area (not a town), which is actually part of three towns – Norwalk, New Canaan, and Wilton.  The Silvermine River runs through the center of Silvermine, which is approximately three miles long and one mile wide.  Map 2.2 shows the area of Silvermine.  Although used to describe the area since at least the early part of the eighteenth century, no convincing evidence of a “Silvermine” has yet been found.

Early settlement in the area is attributed to water-powered mills, with agriculture also contributing to the growth of the area.  Industrial development in the area along the river dates to the seventeenth century.  As the Industrial Revolution gripped New England, steam power replaced the water wheel and early turbines, ushering in the era of large-scale manufacturing.  The smaller mills located along the Silvermine River , functionally dependent on their location, could not expand to compete with these works and soon began to suffer.

The American Renaissance, an arts movement beginning in the late nineteenth century with America’s centennial celebration, helped transform the declining mill village of Silvermine into a thriving arts center.  Beginning with a single artist’s relocation to the area in 1906, Silvermine blossomed with the arrival of sculptors, painters, writers, actors, and musicians.  Interestingly, it can be stated that the decline of the industrial endeavors produced cheap building stock which was an essential ingredient to the development of the arts colony.  The art community in Silvermine continues to flourish, thanks in no small part to the Silvermine Arts Guild, a group active since the 1920s.

Silvermine today exhibits a range of influences: the rural New England mill village; the secluded artist colony; post-World War II development; and regional tourism.  There are active community groups concerned with the preservation of this unique area.  The core of the Silvermine area has been deemed eligible for the National Register of Historic Places, and a Historic District nomination is in process.

Site Description

The location of the Silvermine Avenue Retaining Wall and Culvert lies in the southern fifth of Silvermine (N 41.13665, W -73.4398; UTM 18 630946E, 4555100N).  The structure consists of a raised roadbed that carries Silvermine Avenue over Silvermine Brook which drains into the Silvermine River, located approximately 350 ft to the east.  Dry-laid, hand-stacked, stone retaining walls, with a maximum height of 10.5 ft, line both sides of the earthen road fill; a small culvert allows Silvermine Brook to pass beneath the 26 ft-wide roadway.  Photograph 1.1 shows that the Silvermine Avenue Retaining Wall and Culvert is invisible from the road; most of the traveling public has no concept of the intricate structure upon which they are driving.

Silvermine Brook runs very slowly here as it falls over a small rock dam and around piles of rocks before it enters the stone culvert (Photograph 1.2).  Angled rock walls direct the flow into the culvert, which is approximately 3.5 ft wide and 4 ft from water surface to the top of the culvert opening.  Photograph 1.3 details that the Silvermine Avenue Retaining Wall and Culvert is constructed with a variety of stones.  The square-box stone culvert has a single lintel cap on each side.  Shown in Photograph 1.4, these lintels are the only stones which have visible quarry marks.  The other stones used in the structure are a vast array of sizes and shapes, including glacially-deposited field stone; there is no observed pattern to the construction.  The total length of the structure on the upstream side is approximately 50 ft.  Photograph 1.5 shows the upstream side of the Silvermine Avenue Retaining Wall and Culvert, where there is evidence of mortar added as a previous repair measure.  Much of this mortar has separated and spalled from the wall itself and is no longer offering any support.

On the downstream side, the Silvermine Avenue Retaining Wall and Culvert does not have any evidence of mortar repair.  It appears that the depth of the brook bed increases as Silvermine Brook enters the culvert; there is a deep, almost still pool on the downstream side of the structure which is shown in Photograph 1.6.  An adjacent homeowner states that a large pipe visible in this pool carries a waterline across the brook.  The structure is noticeably longer here (roughly 130 ft).  Silvermine Avenue makes a bend at the point where it crosses Silvermine Brook; the downstream side is the outer part of the curve.  Photograph 1.7 shows the southern section of the structure, which is approximately 65 ft long, tapering from the culvert opening.  The northern section detailed in Photograph 1.8 is approximately 60 ft long; this is the area where the bulging is observed.  There is a pipe protruding from the retaining wall on this section.  The homeowner referenced above states that when the City flushes out the fire hydrants, water shoots out of the pipe into Silvermine Brook.

Detailed in Photograph 1.9, the northern section of the downstream side also exhibits an interesting feature.  Protruding stones with metal tie rod imbedded in them are evenly spaced along the wall.  The ties angle up towards the road.  As they are integrated into the wall, it can be reasonably assumed that they were a characteristic of the original construction.  Inspection of these did not immediately present a clear function.  One possible explanation is that they were part of an early guardrail system.  There is evidence of cut-off wooden posts at the edge of the road.  Modern metal guardrails now exist farther back from the edge of the road.  These metal tie rods do not exist on the upstream side of the Silvermine Avenue Retaining Wall and Culvert.

Site History

Silvermine Avenue continues to be a major north-south route connecting the historic Silvermine area with the City of Norwalk.  Map 2.3 shows Silvermine Avenue crossing the Silvermine Brook in 1851.  It logically follows that the Silvermine Avenue Retaining Wall and Culvert is carrying Silvermine Avenue over Silvermine Brook on this map, and therefore has existed at least since 1851.  Map 2.4 shows the same area of Norwalk in 1874. 

Both maps detail the vicinity around the Silvermine Avenue Retaining Wall and Culvert.   It should be noted that, although early industrial development occurred in this general area during the early to mid-nineteenth century, these maps show the area immediately surrounding the structure to be primarily rural with few homes and no noted mill buildings in both 1851 and 1874.

Agriculture and water-powered mills fostered the initial wave of settlement in Silvermine. These industries needed a road system which would function year-round in order for their goods to be transported to markets.  As early as 1819, materials were routinely ferried between Norwalk and New York City.  Silvermine Avenue aided the entrepreneurs of Silvermine by providing a key link to these cities.  The Silvermine Avenue Retaining Wall and Culvert would have been essential for the construction of this important road, as it elevated the roadbed over the Silvermine Brook, thus making the road passable even during periods of high water.

Bibliography

Books

Pease John C. and John M. Niles.  A Gazetteer of the States of Connecticut andRhode Island: Written with Care and Impartiality, From Original and Authentic Materials:Consisting of Two Parts...: With an Accurate and Improved Map ofEach State. Bowie, MD : Heritage Books, 1991.

Individuals

Esser, Phillip. Associated Cultural Resource Consultants.
Grant, Leigh. President, Norwalk Association of Silvermine Homeowners.

Maps

Clark, Richard “Map of the town of Norwalk 1851,” courtesy of Leigh Grant, Norwalk Association of Silvermine Homeowners.

University of Connecticut Libraries MAGIC HistoricalScannedMapCollection.“TownofNorwalkFairfieldCo.<st1:statew:st="on">Conn.,
magic.lib.uconn.edu/cgibin/MAGIC_HistDisp.pl?&Geog=37840&Loc=103&Dir= /magic/data/image/37840/hdimg/all/&File=37840.103.1874.s32.unkn.1(accessed July 13, 2007).

National Register of Historic Places Nominations

Graziano, Paul and Phillip Esser. 2007.  Silvermine Historic District National RegisterNomination.  Ed. Leigh Grant.

Websites

Norwalk River Watershed Association, Inc. “Silvermine Brook,” Norwalk River Watershed Association, Inc., www.norwalkriver.org/silverminebrook.htm (accessed July 11, 2007).

The Silvermine Tavern, “Walking Tour,” Silvermine Tavern, www.silverminetavern.com/walking_tour.htm  (accessed July 11, 2007).

Useful Links

 

Last Modified: Thursday, 15-May-2008 15:08:07 EDT