Roads and Bridges in a Landscape
There are many resources within a rural historic landscape (District), some of which are bridges, and these are the specific resources in which we are interested. How is a bridge part of a landscape and how would we determine what is contributing or not from a significance standpoint? In considering the landscape characteristics outlined above, a bridge is part of a road system and represents the process of a pattern of spatial organization (McClelland et al, n.d.,p:4). One feature that is relevant to the landscape characteristic is the pattern of the circulation network, which is further described as “paths, roads, streams, or canals, highways, railways, and waterways.” (p. 16). For roads and bridges, the documentation is to “describe the principal forms of transportation and circulation routes that facilitate travel within the landscape and connect the landscape with its larger region,” and, to “identify principal roadways and other transportation routes and classify as contributing or noncontributing” [emphasis provided by Bulletin] (p. 16).
This is a critical statement in separating contributing from non-contributing resources. As part of the circulation network, principal roadways – and their associated components – would be considered contributing. Roadways that are not principal in the context of the Landscape’s evolutionary history would be considered noncontributing. This statement also undercuts a view that since agriculture depends on a road system to bring goods to market, the entire network should be contributing. Methods for considering what roadways are principal are presented below.
The second relevant characteristic is the physical component of Buildings, Structures, and Objects, which in this case, includes the bridges and highways. The documentation in part is to “identify patterns and distinctive examples of workmanship, methods of construction, materials, stylistic influences, and vernacular forms”, as well as to “describe the principal and most important buildings, structures, and objects, by name, type, location…methods of construction, materials, stylistic influence, and if known, builder” (p. 17) (my emphasis)
Specifically for rural historic landscapes that achieve their significance under Criterion A for agriculture, these physical components as well as the boundary demarcations, the vegetation related to land use, the “clusters,” archaeological sites, and even small-scale elements need to relate to the agricultural land use and activities, agricultural adaptations, and agricultural response to the natural environment. The historic context within which these physical components should be interpreted has largely been established by the MPDF, but for specific landscapes, telling the story of that farming system’s specific evolutionary trajectory requires that each physical component’s contributing or noncontributing status be filtered through that particular lens. For landscapes in particular, contributing resources provide tangible evidence of that evolutionary trajectory, i.e. they must help tell the story.
Looking at the bridge as reflected in both the circulation network and the physical component of the structure within the Landscape requires that we clarify what we mean when we talk about a “bridge.” Bridge is a shorthand for multiple features, each of which is relevant to the discussion of whether the “bridge” would be contributing or not. First, within the circulation network, the bridge is a crossing that connects pieces of the road network. If we are to concede that the circulation network is an important characteristic of what makes a Landscape significant and what helps define its integrity, we must separate the crossing from the other “bridge” features. In addition, if we are to assess whether the crossing contributes or does not contribute to the Landscape, we also need to assess which are the principal roads within the Landscape. It is reasonable to assess principal in terms of which roads and which part of the network were most important to the agricultural functioning of the Landscape, both as an internal system, and, also as an external connection, i.e., bringing products to markets. A crossing on a non-contributing road would not be contributing to the Landscape. Crossings on principal roads would be contributing and although this seems a trivial statement, it does factor into matters of effect if a bridge project seeks to close off part of the roadway, or is part of a road relocation that substantially changes the network footprint, such as in a bypass.
The second and third features of the bridge represent the physical component, representing the superstructure andthe substructure. It is necessary to consider these features separately, because there can be separate construction episodes, as a bridge substructure may be re-used while the superstructure is replaced. This parsing of the bridge into two pieces requires that each piece be considered separately. In doing so, the bridge has the ability to more precisely reflect what part contributes and what does not.
Starting with the substructure, the central question becomes “how does the construction and operation of the substructure, e.g. abutments, wing walls, piers, etc. tell the story of the agricultural evolutionary trajectory of that particular landscape?” In almost all instances, the substructure of a rural bridge would be composed of stone, or concrete, or a combination of the two. A stone substructure made of local stone would more likely be able to represent the workmanship, methods of construction, materials, stylistic influences, and vernacular forms that express the Landscape in which it is set. A stone substructure composed of quarried stone from outside the Landscape, or a concrete substructure, built following a state standard design, would be less likely to express that local workmanship, local method of construction, local material, local stylistic influences, and local vernacular forms that are significant in the landscape’s agricultural evolutionary trajectory. The difference between stone and concrete could be the difference between contributing and non-contributing elements. Looking at the substructure by itself, it may also be reasonable to assess whether pieces of the substructure are retained or whether they have suffered the loss of integrity of design, materials, or feeling. For example, if a locally designed substructure has been so modified in repair that it is no longer recognizable, with regards to design, materials, or feeling, the substructure may lose sufficient integrity to no longer be contributing.
Likewise, the superstructure as a physical element can express the landscape’s agricultural evolutionary trajectory or not. Superstructures constructed under the design of a local bridge engineer, or of local (stone) materials, could be argued to help tell the story of the landscape’s agricultural evolution, through local workmanship, local method of construction, local material, local stylistic influences, and local vernacular forms. These structures would not necessarily have to be early. During the CCC era, local engineers and workman built bridges out of local material using local knowledge. These structures might tell the story of an agricultural trajectory of that period, buttressed by an emergency wage economy. In wealthier regions, the local government might have undertaken a program of bridge construction to improve transportation of goods to market, locally led and locally funded. These bridges might also tell the story of an agricultural trajectory of that period.
Conversely, a concrete state standard design bridge superstructure (and maybe substructure, too) that is constructed within a Landscape through a statewide bridge building program might be considered non-contributing, as it fails to demonstrate the local, vernacular form, even while maintaining a crossing on a principal roadway.
Looking at the superstructure by itself, it may also be reasonable to assess whether pieces of the superstructure are retained or whether they have suffered the loss of integrity of design, materials, or feeling. Commonly in rural settings, the bridge superstructure is invisible to the travelling public and the barriers along the bridge have been replaced several times since original construction. In this circumstance, the superstructure might not be able to convey the locally important (workmanship and vernacular design) landscape characteristics associated with the circulation network.
Considering all three elements in a bridge, it is possible that any of the three could be considered a contributing resource. A crossing on a principal road within the Landscape might be contributing, although the substructure and superstructure were state standard-design of non-local concrete. The substructure might be contributing, having been constructed out of local stone, while the superstructure was a state-standard design that was placed 50 years after the substructure but still within the period of significance.
The approach outlined here offers an opportunity to closely align decisions about bridges being contributing/non-contributing with both the NR guidance and the MPDF for agricultural Landscapes. The approach also resolves a certain fuzziness that arises when consideration of a bridge is taken as a simple all or nothing decision that tries to push the arguments into a simple yes/no format, e.g. roads and bridges are a necessary part of any rural historic district, leaving the only unresolved matter is determining whether the bridge was built during the period of significance. Separating substructure from superstructure allows consideration of construction events and structures that may be different over material, design, and time. It avoids conflating both sub-and super-structures into one potentially dis-unified whole, where we are forced to dismiss abutments and piers that might be wholly consistent with local materials, construction, vernacular design, etc. because the overlying superstructure is relatively modern and not in local harmony, having been imposed as part of actions wholly outside of the local landscape.
The downside of the approach outlined here is one of information and knowledge, specifically the work required to obtain the information and knowledge to put each bridge through this 3-part analysis. Presuming we understand we have a rural historic district present and know for what it is significant (a big presumption), we still must figure out whether the crossing is on a principal roadway, and whether the substructure and superstructure are part of the important story that this Landscape tells.