Historic Resource Impact Studies (Part 1)

One of the most exciting parts of our work is preparing Historic Resource Impact Studies. Impact Studies are required by many municipalities in Southeast Pennsylvania when a land development application is proposed for a property containing a historic resource (usually identified in a Historic Resource Survey) or within a certain number of feet of a historic resource. The general goals of impact studies are to encourage the preservation and reuse of historic resources and to foster a dialogue between the applicant and the municipality.

Impact Studies are usually prepared by qualified historic preservation professionals, such as Wise Preservation Planning. They should be written by someone who meets the federal guidelines for architectural historians (48 FR 44716 and 36 CFR 61). They are based on engineering plans and sometimes architectural renderings as presented by the developer. The process is usually overseen and reviewed by the municipality’s Historical Commission. For the developer, it is best to retain a consultant with experience dealing with all participants (applicant; the applicant’s project team – attorney, engineer, land planner and architect; adjacent land owners – if applicable; and the municipality). Wise, for example, is often recommended to a developer by the municipality; however, the developer retains Wise for the project.

Impact Studies accomplish three specific goals:

1) They document the history and significance of the historic resource. Impact Studies begin with a site survey and inspection to identify the historic resources involved. Photo documentation and measured drawings are usually prepared for any resources planned for demolition. Thereafter, the history of the property is researched. Information from the site visit and history are used to develop a statement of signficance for the historic resources.

2) They determine the level of potential adverse impact of the development on the resource and its setting. One of the main purposes of an Impact Study is to protect historic resources and their settings (sometimes called the “heritage zone”). The consultant considers the proposed plan and how it will impact the historic resource. Wise developed the scale of impact that is used by many municipalities in southeastern Pennsylvania for impact studies, which we will discuss in a later blog.

3) They recommend measures to mitigate any adverse impact. Some recommended changes may be minor, such as vegetative buffers; other mitigation recommendations may explore plan alternatives, such as road locations, building siting, and parking design.

Impact Studies go through two review stages. After completing the first draft, Wise submits the draft impact study to the applicant. Applicants need to weigh the impacts and recommendations, as on occasion a recommendation is not feasible for reasons unknown to the preparer. Often the applicant is able to amend the plan in response to the impact study and thus offer a preferable plan to the historical commission. Once the applicant has approved the text, the final, revised version of the impact study is submitted to the municipality, usually to a Historical Commission. It is very important for the municipality to carefully review each study and ensure that all bases are covered, meaning that all impacts are carefully considered and mitigation explored. For their part, applicants need to be able to “defend” their plans against Impact Study recommendations; Impact Studies are rarely “rubber stamp” approvals of plan (though many plans do create very low level impacts and thus make only minor mitigation recommendations). The Commission usually makes its recommendations to the Governing Body based on recommendations in the Impact Study or as a result of subsequent discussions.

Wise has been involved in all aspects of the impact study process. We have assisted several municipalities in drafting their historic resource protection ordinance, including language for impact studies. Wise has completed scores of Impact Studies or related plan reviews throughout Southeast Pennsylvania, virtually setting the standard for all aspects of the process. On occasion, we have been asked to consult with a historical commission in the plan review of applications drafted by other firms.

Our projects vary. We have examined the impacts of simple subdivisions, the construction of new retail plazas, to large residential developments containing several hundred units. We have consulted on the adaptive reuse and development of estate properties, and conversely the demolitions of high profile buildings such as Lower Merion Township’s historic “La Ronda” mansion.