Chapter 6: Shadows A. INTRODUCTION · Chapter 6: Shadows 6-3 of the incremental shadow resulting...

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Chapter 6: Shadows

A. INTRODUCTION This chapter examines whether the proposed project would cast new shadows on any sunlight-sensitive resources and assesses the possible effects of any such new shadows. Public open spaces, historic, cultural, and natural resources are all potentially sunlight-sensitive resources, and, therefore, this chapter is linked to the information presented in other sections of this environmental impact statement (EIS), particularly Chapter 5, “Open Space,” Chapter 7, “Historic Resources,” and Chapter 9, “Natural Resources.”

According to the 2012 City Environmental Quality Review (CEQR) Technical Manual, a shadows assessment is required if a proposed project would result in structures (or additions to existing structures) of 50 feet or more, or be located adjacent to, or across the street from, a sunlight-sensitive resource. As described in Chapter 1, “Project Description,” the project would include the construction of rooftop additions, both on the pier’s headhouse and on the finger building, or pier shed. On the north side of the lower headhouse rooftop, a new enclosure would be built to provide additional space for retail. This new enclosure would be lower than the east headhouse façade along Eleventh Avenue, but higher than the north façade. Another enclosure would be built in the center of the upper headhouse rooftop. This enclosure would be lower than the east headhouse façade along Eleventh Avenue, but would be higher than the north and south façades of the headhouse. On the pier shed roof, a new pavilion and three shade structures would be constructed. In addition, the proposed project would include a marina, which would result in new shadows on the Hudson River.

None of the new additions would reach 50 feet in height. However, the project site is adjacent to the Hudson River, an important natural resource, as well as the Hudson River Park waterfront esplanade and the Route 9A bikeway, located adjacent to Hudson River Park. Therefore, a shadows assessment is warranted.

PRINCIPAL CONCLUSIONS

New shadows from the proposed rooftop structures and marina would fall on the Hudson River in all seasons, and on small areas within Hudson River Park adjacent to Pier 57 in the fall, winter, and early spring. The new shadows would be limited in extent and duration and would not cause significant adverse impacts to these resources.

B. DEFINITIONS AND METHODOLOGY DEFINITIONS

Incremental shadow is the additional, or new, shadow that a structure resulting from a proposed project would cast on a sunlight-sensitive resource.

Sunlight-sensitive resources are those resources that depend on sunlight or for which direct sunlight is necessary to maintain the resource’s usability or architectural integrity. Such resources generally include:

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• Public open space (e.g., parks, beaches, playgrounds, plazas, schoolyards, greenways, landscaped medians with seating). Planted areas within unused portions of roadbeds that are part of the Greenstreets program are also considered sunlight-sensitive resources.

• Features of architectural historic resources that depend on sunlight for their enjoyment by the public. Only the sunlight-sensitive features need be considered, as opposed to the entire resource. Such sunlight-sensitive features might include: design elements that depend on the contrast between light and dark (e.g., recessed balconies, arcades, deep window reveals); elaborate, highly carved ornamentation; stained glass windows; historic landscapes and scenic landmarks; and features for which the effect of direct sunlight is described as playing a significant role in the structure’s importance as a historic landmark.

• Natural resources where the introduction of shadows could alter the resource’s condition or microclimate. Such resources could include surface water bodies, wetlands, or designated resources such as coastal fish and wildlife habitats.

Non-sunlight-sensitive resources, for the purposes of CEQR, include:

• City streets and sidewalks (except Greenstreets); • Private open space (e.g., front and back yards, stoops, vacant lots, and any private, non-

publicly accessible open space); • Project-generated open space. Project-generated open space cannot experience a significant

adverse shadow impact from the project, according to CEQR, because without the project the open space would not exist. However, a qualitative discussion of shadows on a project-generated open space should be included in an analysis.

A significant adverse shadow impact occurs when the incremental shadow added by a proposed project falls on a sunlight-sensitive resource and substantially reduces or completely eliminates direct sunlight, thereby significantly altering the public’s use of the resource or threatening the viability of vegetation or other resources. Each case must be considered on its own merits based on the extent and duration of new shadow and an analysis of the resource’s sensitivity to reduced sunlight.

METHODOLOGY

Following the guidelines of the CEQR Technical Manual, a preliminary screening assessment must first be conducted to ascertain whether shadow from the proposed rooftop additions could reach any sunlight-sensitive resources at any time of year. The preliminary screening assessment consists of three tiers of analysis. The first tier determines a simple radius around the proposed additions that represents the longest shadow that could be cast. If there are sunlight-sensitive resources within this radius, the analysis proceeds to the second tier, which reduces the area that could be affected by project-generated shadow by accounting for the fact that shadows can never be cast between a certain range of angles south of the project site due to the path of the sun through the sky at the latitude of New York City.

If the second tier of analysis does not eliminate the possibility of new shadows on sunlight-sensitive resources, a third tier of screening analysis further refines the area that could be reached by project-generated shadow by looking at specific representative days of the year and determining the maximum extent of shadow over the course of each representative day.

If the third tier of analysis does not eliminate the possibility of new shadows on sunlight-sensitive resources, a detailed shadow analysis is required to determine the extent and duration

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of the incremental shadow resulting from the project, taking into account existing buildings and their shadows. The detailed analysis provides the data needed to assess the shadow impacts. The effects of the new shadows on the sunlight-sensitive resources are described, and their degree of significance is considered. The results of the analysis and assessment are documented with graphics, a table of incremental shadow durations, and narrative text.

C. PRELIMINARY SCREENING ASSESSMENT A base map was developed using Geographic Information Systems (GIS)1 showing the proposed project and the surrounding river and street layout. In coordination with the information regarding open space, historic, and natural resources presented in other sections of this EIS, potentially sunlight-sensitive resources were identified and shown on the map.

TIER 1 SCREENING ASSESSMENT

According to the CEQR Technical Manual, the longest shadow that a structure can cast at the latitude of New York City occurs on December 21, the winter solstice, at the start of the analysis day at 8:51 AM, and is equal to 4.27 times the height of the structure.

Using the longest shadow distance as a radius, a perimeter was drawn around the rooftop structures. The assessment concluded that project-generated shadow would be long enough to reach portions of the Hudson River, the Hudson River Park waterfront esplanade, and the Route 9A bikeway. No other sunlight-sensitive resources could be affected by project-generated shadow.


Because of the path that the sun travels across the sky in the northern hemisphere, no shadow can be cast in a triangular area south of any given project site. In New York City, this area lies between -108 and +108 degrees from true north. The complementing area to the east, north and west represents the remaining area that could potentially experience new project-generated shadow. Since portions of the Hudson River, the Hudson River Park waterfront esplanade, and the Route 9A bikeway were located within the remaining shadow study area to the northeast and northwest, additional assessment was required.


A Tier 3 assessment is typically conducted to further refine the area that could be reached by project-generated shadow, by using three-dimensional (3D) computer software to model specific representative days of the year and determining the maximum extent of shadow from the proposed structures over the course of each representative day.

The Tier 3 assessment indicated that shadow from the proposed rooftop structures could, absent existing structures such as the pier shed and the headhouse, fall on the river in all seasons and on the Hudson River Park waterfront esplanade and Route 9A bikeway in the fall, winter and early spring. Consequently, a detailed analysis was necessary to determine the extent and duration of project-generated shadows, given the existing structures and the shadows they already cast.

1 Software: Esri ArcGIS 10; Data: New York City Department of Information Technology and

Telecommunications (DoITT) and other City agencies


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D. DETAILED SHADOW ANALYSIS The direction and length of shadows vary throughout the course of the day and also differ depending on the season. In order to determine when shadow from the proposed rooftop additions could fall on the river, Hudson River Park waterfront esplanade and Route 9A bikeway, 3D computer mapping software is used to calculate and display the proposed project’s shadows on individual representative days of the year.1

Shadows on the summer solstice (June 21), winter solstice (December 21) and spring and fall equinoxes (March 21 and September 21, which are approximately the same in terms of shadow patterns) are modeled, to represent the range of shadows over the course of the year. An additional representative day during the growing season is also modeled, generally the day halfway between the summer solstice and the equinoxes, i.e., May 6 or August 6, which have approximately the same shadow patterns.

The shadow assessment considers shadows occurring between one and a half hours after sunrise and one and a half hours before sunset. At times earlier or later than this timeframe window of analysis, the sun is down near the horizon and the sun’s rays reach the Earth at tangential angles, diminishing the amount of solar energy and producing shadows that are long, move fast, and generally blend with shadows from existing structures until the sun reaches the horizon and sets. Consequently, shadows occurring outside the timeframe of analysis are not considered significant under CEQR, and their assessment is not required.

The purpose of the detailed analysis is to determine the extent and duration of new incremental shadows that fall on a sunlight-sensitive resource as a result of the proposed project, and to assess their effects. The detailed analysis establishes a baseline condition (the future without the proposed project, or No Action condition) that is compared with the future with the proposed project (With Action condition) to illustrate the additional (incremental) shadow cast by the project. Because existing structures may already cast shadows on a sun-sensitive resource, the proposed project may not result in additional, or incremental, shadows upon that resource.

The analysis results are described below for each analysis day. Table 6-1 summarizes the results of the detailed analysis. It shows the entry and exit times and total duration of project-generated incremental shadow on each affected resource. Figures 6-1 through 6-11 document the results of the analysis by providing graphic representations or “snapshots” of times when incremental shadow would fall on a sun-sensitive resource. The figures illustrate the extent of additional, incremental shadow at that moment in time, highlighted in red, and also show existing shadow and remaining areas of sunlight. The proposed rooftop additions on the headhouse, pavilion, and shade structures are indicated on these figures.

The section of Hudson River Park adjacent to Pier 57 consists of the Hudson River Park waterfront esplanade. The Route 9A bikeway is located adjacent to Hudson River Park to the east. Narrow landscaped areas are located in the area between the Hudson River Park waterfront esplanade and the Route 9A bikeway, and the Route 9A bikeway and the Route 9A roadway. For this assessment, the entire width of the Hudson River Park waterfront esplanade and the Route 9A bikeway containing these elements is shown as sunlight-sensitive, due to the vegetation as well as the active and passive recreational uses.

1 Software: MicroStation V8i

HUDSON RIVER PARK PIER 57

March 21/Sept. 21 - 9:30 AM ESTFigure 6-1

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March 21/Sept. 21 - 12:00 PM ESTFigure 6-2

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June 21 - 5:57 AM ESTFigure 6-6

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December 21 - 8:51 AM ESTFigure 6-7

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December 21 - 10:30 AM ESTFigure 6-8

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December 21 - 12:00 PM ESTFigure 6-9

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Table 6-1 Incremental Shadow Durations from Pier 57 Modifications

Sun-sensitive resources

March 21 / Sept. 21 7:36 AM-4:29 PM

May 6 / August 6 6:27 AM-5:18 PM

June 21 5:57 AM-6:01 PM

December 21 8:51 AM-2:53 PM

Hudson River 8:30 AM–4:29 PM Total: 7 hr 59 min

6:27 AM–7:00 AM Total: 33 min

5:57 AM–7:30 AM Total: 1 hr 33 min

8:51 AM–2:53 PM Total: 6 hr 2 min

Hudson River Park / Route 9A Bikeway

3:30 PM–4:29 PM Total: 59 min

— — 2:30 PM–2:53 PM Total: 23 min

Notes: Table indicates entry and exit times and total duration of incremental shadow for each sunlight-sensitive resource. Daylight saving time is not used.

The proposed marina surrounding the pier would consist of slips and walkways on or just above the surface of the Hudson River, and piles under it. It may also include a water taxi landing. The walkways and water taxi landing would cast shadow directly onto the surface of the water. It is therefore not necessary to analyze them further to determine where their shadows would fall. The proposed marina and the shadows it would cast on the water are not shown in the figures, in order to clarify the shadows from the rooftop structures, but are discussed in the section “Probable Impacts of the Proposed Project” below.

MARCH 21/SEPTEMBER 21

On March 21 and September 21, shadows are of moderate length, and shadows from the proposed rooftop additions would reach past the edges of the existing pier shed or headhouse to fall on very small portions of the river for most of the day, and the bikeway and esplanade for about the final hour of the analysis day (see Figures 6-1 to 6-4). Specifically, the proposed enclosure on the north side of the headhouse would cast a small area of shadow north onto a section of the river beginning at 8:30 AM; this area of shadow would move eastward over the course of the day until about 3:15 PM when it would move off the river completely. From 3:30 PM until 4:29 PM this shadow would fall on a small area of the bikeway. Beginning at about 10:30 AM, shadows from the tops of the shade structures on the pier shed roof would fall on portions of the river, moving eastward across the surface of the water until the end of the analysis day at 4:29 PM.

MAY 6/AUGUST 6

On this late spring and summer analysis day, shadows are shorter but fall further south at the start and end of the day. Shadows from the shade structures would briefly fall on the river to the southwest in the first several minutes of the analysis day (see Figure 6-5), but after that they would be too short to fall beyond the shed roof onto the river at any point for the rest of the day. The proposed new enclosure on the center portion of the headhouse roof would cast a new shadow on the river during the first half hour of the analysis day.

JUNE 21

Shadows are shortest on this day, and similar to May 6 and August 6, small incremental shadows would fall briefly on the river early in the morning, for a total of about an hour and a half (see Figure 6-6).

DECEMBER 21

On December 21, shadows are longest. Incremental shadow from the upper parts of the shade structures, pavilion, and headhouse addition would move across portions of the river north of the


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pier all day (see Figures 6-7 to 6-11). Incremental shadow would also fall on a small section of the bikeway and esplanade for the final 23 minutes of the analysis day.

E. PROBABLE IMPACTS OF THE PROPOSED PROJECT HUDSON RIVER

The portions of the Hudson River that are adjacent to the project site are part of the Hudson River Park Estuarine Sanctuary. On the March 21/September 21 and December 21 analysis days, small areas of incremental shadow would move across portions of the river for long durations. On the late spring and summer analysis days, the duration of new shadow would be limited to an hour and a half or less, and would be small for most of the affected period.

The areas of new shadow would move over the course of the day, not falling on one particular area for long. The current flows swiftly in the Hudson River and would move phytoplankton and other natural elements quickly through the shaded areas. The areas of the river that would receive the longest durations of new shadows would continue to receive ample sunlight in the midday and afternoon, because there are no intervening structures to the west. Therefore, given their limited duration and extent, incremental shadows generated by the proposed project would not have significant adverse impacts on primary productivity within the Hudson River.

As noted above, the proposed marina’s walkways and the proposed water taxi landing would cast shadow onto the river. The proposed marina walkways are anticipated to be approximately 8 feet wide and its fingerfloats 4 feet wide. The proposed water taxi landing would be approximately 30-feet by 60-feet. The total maximum new overwater coverage resulting from the marina and water taxi landing would be about 1.1 acres. Although the proposed project would result in increase in overwater coverage within Hudson River Park, the increase in shading of aquatic habitat would be minimal due to the narrow width of the fingerfloats and walkways. The narrowness of the walkways and the gaps between them would permit some light to reach the water and mudline under them. The New York State Department of Environmental Conservation (NYSDEC) generally considers aquatic habitat under an overwater structure to be shade-impacted after the first 15 feet from the structure’s edge. Therefore, as discussed in the natural resources analysis presented in Chapter 9, it was determined that these walkways associated with the marina would be expected to not result in significant adverse impacts to the habitat from shading and would not adversely affect the Hudson River Park Estuarine Sanctuary.

HUDSON RIVER PARK WATERFRONT ESPLANADE AND ROUTE 9A BIKEWAY

Incremental shadow from the proposed rooftop additions would be very small on the Hudson River Park waterfront esplanade and adjacent Route 9A bikeway, would have duration of less than an hour, and would only occur in some months (the fall, winter and early spring). This limited extent and duration of new shadows would not cause a significant adverse impact.

PROJECT-GENERATED OPEN SPACE

The new open spaces that would be developed within the proposed project include rooftop open spaces on the pier shed roof and a perimeter walkway at grade level.

The proposed rooftop open spaces would be mostly in sun throughout all four analysis days, with the exception of small areas adjacent to the proposed pavilion and shade structures on their north sides.

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The north side of the proposed perimeter walkway would be in shadow for much of the day in all seasons, except for during early mornings and late afternoons in the late spring and summer. The shorter west section of the walkway would be shaded in the mornings and in sun during the afternoons. The south side of the walkway would be in sun for most of the day in all seasons. As discussed above, these shadows would not constitute a significant adverse impact because without the project the open space would not exist.

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