ADDITIONAL DESIGN GUIDELINES RELATING TO INTERSTATE HIGHWAY AND THE GREAT LAWN

Purpose

Several plans have been generated by the Kentucky Indiana Bridges Project for modifications to the section of I-64 that crosses over Waterfront Park’s Great Lawn. The Federal Highway Administration (FHWA) is responsible, under SAFETEA-LU to ensure that impacts do not “. . . adversely affect the activities, features and attributes...” of a Section 4(f) resource. Of course, Waterfront Park is such a resource.

Pursuant to KRS 82.660-82.670 the Waterfront Overlay District was established. Louisville Metro Ordinance Number 66-2004 provides guidance for design review, confers authority for review and permitting to the Waterfront Development Corporation, and allows the corporation to “... adopt additional standards consistent with the policies and standards established herein [in the ordinance] for the purpose of interpreting and supplementing the policies and standards established ... ”for the Waterfront District.
This document provides additional standards to assist Waterfront Development Corporation Board of Directors in its determination of design appropriateness. In should also be used by the Bi­State Management Team and the FHWA to ensure that highway impacts not adversely affect activities, features, and attributes of Waterfront Park in general and specifically the Great Lawn.

Impacts

Primarily, adverse impacts to the Great Lawn result from a 46 percent increase in the width of the interstate deck. This 71 foot widening of the I-64 deck and placement of structural supports in the park create a visual and psychological barrier in the park. Impacts will also result from placement of drains to handle the larger surface area’s additional precipitation and location and style of expansion joints and lights.

Deck widening will not only impact the scale and massing of that which looms over the Great Lawn but it will also change the image of the Great Lawn itself by bifurcating the Great Lawn as two smaller lawns divided by a deck so wide that grass will be shaded to a point of inadequate sunlight for growth. As the grass dies under the widened deck, it will necessitate replacement with an inorganic surface. Thus, the Great Lawn becomes two less than “great” lawns. Of course additional piers will work in tandem to create and reinforce that undesirable image. If piers occupy the same type of spacing become larger or increase in numbers, the increased vertical obstruction will further divide the lawn visually.

Visually and physically dividing the Great Lawn is an enormous impact with design implications that go well beyond the obvious. If not handled with sensitivity this section of highway improvements will not only adversely impact Great Lawn features and attributes but will violate the very design philosophy on which Waterfront Park was built. Specifically, in 2001 the American Society of Landscape Architects granted its highest award to Waterfront Park. In citing the design jury’s reasoning for rational recognition of excellence, Waterfront Park’s Great Lawn was the feature that was singled-out as best illustrating the park’s design philosophy of access between the downtown urban experience and the river’s natural experience. The Great Lawn was characterized as, “... flowing under the freeway... [to] reconnect the river with downtown.”

Significant attention was given to channeling drainage from I-64 so to reduce the potential of soggy soil interfering with activities on the Great Lawn. Additional drainage conduits could threaten the design, by adding more vertical elements to the highway and threaten current capacity of storm sewer lines.
Noisy expansion joints are a notorious and unnecessary reminder of the proximity of the highway. A simple walk in the park need to be punctuated by the cadence of randomly speeding vehicles. An increase in deck width necessitates longer expansion joints and increased auditory impacts to park activities.

Lighting design for the new Interstate is another potential impact to park activities and attributes. Consistency of lighting can help unify the Great Lawn’s image at night.

Design Criteria: Gateway vs. Barrier

The interstate path over the Great Lawn must be viewed as a landmark gateway for those traveling on the interstate as well as those who are traveling at grade in and around the park. Folks traveling on I-64 should be given a visual cue or landmark that suggests there is an important place below. Such a landmark could be the structure of bridge supports that rise above the deck. Of course, the “clean” design which we have been striving to achieve elsewhere in the bridges project should be the basis from which this component is designed.

Perhaps a more important landmark is the gateway under I-64 on the Great Lawn. The post­and-lintel structure currently employed to support the interstate deck cannot be the system chosen for a wider deck, as it would solidify the concept of I-64 as a barrier rather than a gateway. The concept of a gateway only works when the viewer is visually invited to an area or site. The Great Lawn presents a particularly unique design problem because the gateway is in the middle of the site. It must be large enough to be recognized as a landmark. It must “frame” a view through the area, under the interstate, so that it invites the public to enjoy the Great Lawn-to-river experience. It must have simple and continuous lines so that its presence will not compete with views in the park by drawing attention to itself, but rather help the public focus on the inviting view offered by the park’s own design.

Finally, the supports that allow bridging the interstate deck must be designed to allow a maximum span across the Great Lawn. Added width to the deck’s surface will significantly alter depth perception for those viewing the Great Lawn and River. The only method to open that view is to design a support structure that widens the view’s horizontal axis to be more proportional with the structure’s depth axis, thereby reducing the visual perception of a utilitarian roof over a third of the Great Lawn. Of course, a typical pier system cannot accomplish this important goal. Whether the piers might be aligned in straight rows or organized in a more random pattern, the psychological message is one of restricting access to the river.

The image of a bridge over the Great Lawn is the most significant single feature that the Bridges Project Team will have an opportunity to design. It will also be the highway feature most viewed by folks in our downtown.

This addendum was approved in a full voting session of the Waterfront Development Corporation Board on February 28, 2007.