The Cambridge Planning and Development Department has estimated that about 2,250 Library visitors might use the Harvard Square station during summer days. Tourists from outside the Boston Metropolitan area are likely to drive to the site and will probably not use the public transportation system. These auto oriented tourist volumes will probably occur between the morning and evening peak rushhour work-trips.
Stable Year Impact
In terms of total numbers, the greatest number of pedestrians attributable to the Library would occur on summer Saturdays. During the course of an average summer Saturday, it is estimated that some 1,800 people would be added to the core area. Assuming that 75 per cent of the existing pedestrian activity level in the Square would take place during the period that the Library was open, the percentage increase during that time due to the Library would be approximately 4 per cent. Since the peak Saturday pedestrian load occurs in the early afternoon hours for both the existing shopping activity and for projected Library visitation, the peak hour percentage increment would be of the same magnitude (4%). On the Library's peak summer Saturday, the increment would be about 7 per cent.
Economic Impact
The total amount of the incremental retail activity generated by the John F. Kennedy Library is estimated to be $1.87 million per year. This total dollar voume is distributed among categories such as gifts, souvenirs, food and beverages, restaurants, specialty goods and hotel/motel accommodations. Of these total dollars nearly $1.1 million are likely to be spent within the Harvard Square area. When compared to currently experienced retail sales volume of the Harvard Square area, this represnts less than 2 per cent change in the retail dollar volume within the Harvard Square retail market is nearly 15 per cent per annum. The change in dollar volume generated by the Library therfore is insignificant. Furthermore, the change in dollar voume by each of the subcategories is also insignificant as discussed within this section.
During the peak year, the dollar volume of the sales may increase to 1.6 million within the Harvard Square Area. When measured in terms of the current Harvard Square dollar sales, this does not represent a significant impact.
Finally, minor changes in hours of operations for the businesses within the square and some changes in their merchandising practices could be anticipated as they attempt to attract the Library visitors.
Convenience Food Outlets and Restaurants
It would appear difficult for a developer to justify any new restaurant or food service construction solely on the basis of revenues generated by Library visitors and users. This does not mean that certain types of convenience food outlets would not flourish in Harvard Square if they were permited to open operations there. In the past five years there have been several instances where national or regional chain operations replaced privately owned restaurants in the vicinity of the Square, and pressures to continue in this direction might well be accelerated by the presence of the Library or even the anticipation of its coming.
The expected increase in Harvard Square visitors due to the bicentennial may encourage one or more chain operations to seek location in the immediate vicinity.
Land Use
The nature and extent of the economic activities generated by the John F. Kennedy Library, are not likely to produce any land use related changes. The net increase in retail sales volume generated by the Library is not likely to induce new restaurant food faclility development in itself because of its seasonal nature, although market forces other than those generated by the Library could induce additional food facilities. No direct office space demand is generated by the Library. The demand for hotel/motel rooms is insufficient to support a new facility of a financially feasible nature. The housing demand created by the Library is minimal and is based upon the assumption that some of the National Archives and Records Service employees of Waltham would prefer to resettle near the Library site.
No major land use changes are anticipated as a result of the Library itself.
The objective of the impact analysis was to evaluate the maximum carbon monoxide levels which could arise as a consequence of both adverse meteorological conditions and peak roadway traffic. Although motor vehicles are also major contributors to community nitrogen oxides and reactive hydrocarbon emissions, these species participate in a series of complex photochemical reactions for which the current atmospheric diffusion modeling technology does not permit preparation of reliable estimates of projected concentration levels. Therefore, emphasis was placed principally on carbon monoxide concentration levels as this pollutant is relatively inert. In addition, carbon monoxide is the pollutant emitted in the largest quantities from automotive sources and possesses the greatest potential for exceeding Federal and Massachusetts air quality standards.
For all cases, predicted carbon monoxide levels will be within air quality standards established by the State and Federal Authorities. The small incremental increase in traffic induced by the project will have an insignificant effect on the attainment and maintenance of such standards. Thus, the project is consistent with the State Implementation Plan developed to insure the attainment of air quality standards required under the Federal Clean Air Act of 1970.
The existing ambient noise is determined largely by street traffic, with the most annoying noise intrusions being produced mainly by trucks and buses. The most significant likely moise contribution by Library activity is from visitor access road vehicles. Shuttle buses for the satellite parking lot and tour buses represent the main potential source of Library related vehicular noise.
The best documented and most tangible adverse effect of environmental noise upon human activity is speech interference. Noise levels below 60 dBA interfere very little with conversational interference occurs above 70 dBA. In the community around the Library site, existing outdoor day-time 10-percentile noise levels range 51-78 dBA, depending on location and day of the week. The 10 percentile daytime noise levels for 17 sampling locations averaged 71 dBA during weekday peak traffic hours, and 67 dBA on Sunday afternoons. Thus the area is already fairly noisy.
The projected Library-related traffic is expected to increase the afore-mentioned average noise levels in the peak year of visitation to 72 dBA during weekday peak hours and 71 dBA on Sunday afternoons. These noise increases of 1-4 dBA are hardly significant but must be considered in the context that noise levels are already high enough (above 70 dBA) to cause significant interference with conversational speech in many outdoor areas.
The projected adverse noise effects are not major but every effort should be made to minimize them. Possible approaches include: encourage visitors to travel by subway; provide carefully conceived street signing to minimize unnecessary "lost" traffic; shuttle and tour buses should be as quiet as possible with direct routing avoiding particularly noise sensitive areas; design and construct the building mechanical systems to prevent excessive noise; construction specifications to prevent excessive noise, particularly from pile driving.
The Library should have at least one beneficial noise impact: the site is not expected to be as noisy as the wheel squeals and banging sounds produced by present MBTA operations