Preserving Sunlight in NYC's Parks

This project was conducted for The Parks Council, New York City and addresses the need for simple and easily administered regulatory controls to prevent the environmental degradation of the city’s inventory of parks at a time when resources are scant and it is urgent to extend to the greatest degree possible the use of parks we already have.

The study found that, under current zoning, some 700 parks – half of the municipal system – are at risk of overshadowing from future development, and proposes zoning regulations to preserve sunlight in these vital public places.

Relying on the Common law principle of a continuing public expectation and on the analysis of the shadow simulations, the study recommends that existing conditions of sunlight and shadow in parks, represented by “green lines,” become the legislative standard. The key to the proposed regulations is the fact that they permit the green lines – the solar access standard – to adjust automatically to specific park conditions like orientation and built context.

Two parallel and equivalent methods are provided for evaluating whether a proposed new building near a park complies with the standard; a traditional prescriptive method and a performance method that determine whether shadows from building forms falls within the “green lines” of a park or if not, within the shadow of an existing building.