Sunday, April 18, 2010

Doyle Drive HALS

I started this blog in October 2009, and now realize I have posted very little about the Doyle Drive HALS project my firm has been working on since November 2008. I believe it’s the largest HALS project currently underway in the United States and as such has been a thrill to be part of. Doyle presented us with several unique challenges and has been tremendously satisfying to work on. In my career the projects I have most enjoyed are those that have been large and complex - given that criteria Doyle Drive is the ultimate challenge and has been immensely satisfying.

The Presidio was designated as a National Historic Landmark (NHL) in 1962 and was listed on the National Register of Historic Places in 1966. The Federal Highway Administration (FHWA), California Department of Transportation (Caltrans), and San Francisco County Transportation Authority (SFCTA) are in the process of replacing Doyle Drive that traverses the Presidio of San Francisco and connects to the Golden Gate bridge in order to improve the seismic, structural and traffic safety of the roadway. As part of the environmental review the Finding of Effect document acknowledged that the project will impact cultural resources.

Historic Documentation
ICF International was retained to complete HABS (Historic American Building Surveys), HAER (Historic American Engineering Record) and HALS documentation as part of the mitigation for the impacts on the cultural resources. The HALS team is being directed by Dana McGowan, Archaeologist with ICF. ICF is doing the historic research and will prepare the historic narrative component of the HALS documents. Brian Grogan has been engaged to complete the HALS photography and PGAdesign is doing the measured drawings. Landscape Historian, Meg Scantleberry is the point of contact for Caltrans and is working closely with the ICF team.

The Project
Doyle Drive is 1.2 miles in length. Portions of the roadway are at grade and much of the highway is on an elevated structure constructed in 1936. The cultural resources that will be potentially impacted by the replacement project include buildings, roadways, stone walls and curbs, concrete batteries, views and historic forests all associated with the Presidio’s 169 year military history. The period of significance is from 1776 to 1945. The project is divided into six planning districts that correlate with districts defined in the National Register nomination.

When we started the project we sought samples of similar work to use as a model, but because the HALS program is so new we found little that was relevant. The project schedule was urgent so we set about creating a methodology that seemed logical and well suited to the task. Our previous work doing cultural landscape inventories (CLI) and reports (CLR) and contributions to historic structures reports (HSR) provided some guide. Our experience with HALS of three of the four California sites was also tremendously helpful, but those sites were all very different and thus not directly applicable to Doyle Drive. Our work on Piedmont Way in Berkeley, California is a surface road – a X block curvilinear parkway conceived by Olmsted. This was our most relevant HALS experience.

Normally the first task in for any cultural landscape documentation effort would be familiarization with the site’s history and a methodical review of existing documentation and historic records and photographs, but because of the immediate urgency of this construction project PGA was forced to start the existing conditions field work without the benefit of such preparation.

Our first task was to decide on what scale the field recording should be done at, what sheet size our final documents should be, and to lay out sheets to cover the irregular but generally linear site. Ultimately 82 sheets were needed to depict the site.

PGA plotted sheets for the area first scheduled for tree removal and got to work. Had time allowed we would have developed our methodology, field tested it, made refinements and retested until our recording techniques were well developed. Without the luxury of time we started our field observations and recording and refined the process each day. This approach resulted in some inconsistencies in recording methods which ideally would have been avoided.

We plotted two sheets for each area; one to record softscape features, i.e. plants, non-paved surfaces, and topography and the other for hardscape features. While in the field we worked in teams of two; one person drew what they saw on the plan sheet while the other made notes on the field inventory form we had created for the project. These teams of two proved an efficient working group and also helped with decisions on what and how to record features. They also provided a degree of safety that was reassuring while working in overgrown areas hidden from view.

The softscape team had existing surveys for tree locations and species identification. We field verified this information making corrections as needed. Shrub and ground cover masses were sketched on the plan while species were identified and listed on the inventory forms. Initially, we recorded a list of species for each sheet, assigned numbers and noted the plant numbers on the plan sheets. After a few days in the field we were able to prepare a plant list of the species we had found in the field. We then assigned each species a two-character acronym for the shrubs, perennials, ground cover and vines, and we used a four-character designation for trees. Cotoneaster lacteus became CL while Pinus radiate/Monterey Pine was PR/MP.

The hardscape team went through a similar process starting with field sketches and written descriptions of features such as curbs, stone walls, rails, lights, etc. Many of these features were occurring repeatedly, so to reduce the time needed to record duplicate descriptions the team developed a system of abbreviated codes and organized them by feature type. This not only reduced field recording time it also improved consistency for how things were being recorded.

These improvements in recording efficiency enabled the observers more time to capture more detail and to do more than just see the site at a micro level of detail. I now had time to look at the whole site and record impressions of what I was seeing. I made notes on what stood out in this piece of the Doyle Drive puzzle trying to capture the character of the site. Later, the pieces of the puzzle would need to be assembled in order to read the whole landscape

Field Photography
To augment the official, large format, black and white photography I used a digital camera to record the existing conditions. I took several types of photographs: 1) detail shots such as manhole covers and concrete stamps which provided data such as dates, contractor and manufacturer’s names, individual plants, signs, rail details, etc; 2) images of individual features like buildings, specimen trees and historic stone walls, 3) overviews of large areas, 4) multiple shots of panoramic views, 5) distant views from particular vantage points, and 6) shots that show topographic changes in the landscape.

Each field day I took 150 – 275 images. At the end of the day I named each image or group of images with a name intended to help the viewer understand what they were seeing and where it occurred.

Collecting the existing conditions data, with our four person crew, took the bulk of two months. Doing the work in winter provided the added challenge of needing to dodge rain and drizzle since we were unable to record field notes if the paper was damp. Rain days actually proved to be good because we used that time to organize material collected and to prepare for the next field day. More on Doyle in a future post.

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