City of Rockville

M E M O R A N D U M

January 6, 2000

TO: Planning Commission

FROM: Planning Staff

SUBJECT: Text Amendment Application TXT1999-00178, Fallsgrove Associates Request for Reduction in Structured Parking Requirement

Background

The applicant had originally proposed a text amendment to reduce the structured parking requirement for office uses in a CPD from 45 percent overall to 25 percent. This was justified by the presence of research and development uses which typically rely on surface parking. However, the Commission expressed concerns during its review about the vagueness of the recommended language, given that research and development (R&D) uses are not defined in the Zoning Ordinance and that a minimum amount of R&D space was not included to determine when a CPD qualified for the reduction. Commissioners expressed difficulty in determining an appropriate minimum amount of structured parking, and that more information was needed. Suggestions were made for a sliding scale of minimum structured parking based on densities of individual office sites, or relating the reduction of structured parking to the environmental benefits received from the overall development.

At the December 15, 1999, meeting, the Commission considered a different approach to the structured parking text amendment. This approach would build on what is believed to be the intent of the structured parking requirement, which was to create additional open space within a CPD. Given that there are now environmental requirements for development, such as the Environmental Guidelines and Forest and Tree Preservation Ordinance which provide for open space, the Commission agreed that relating to structured parking to open space is a valid approach. New text language presented at the meeting would eliminate the structured parking requirement for office uses, but require a minimum percentage of each office site to be vegetated landscaped area. This would ensure that, regardless of whether structured parking was provided, there would be green area on each office site. Staff and the applicant had not agreed on the minimum percentage to be specified, and therefore the Commission agreed to consider this proposed change at its next meeting.

Discussion

Staff from Planning, Public Works, City Forester and the City Attorney's office met to discuss an appropriate percentage of pervious area for each office site, as well as ensuring the intended benefits of the requirement are met. Requiring a minimum amount of pervious area on each site will ensure that the effect of impervious areas on developed sites is mitigated somewhat. Environmental staff agreed that a requirement of 20 percent pervious area for each office site would meet several environmental goals, including minimizing stormwater runoff and reducing heat buildup on open parking lots. This amount was determined to be reasonable, given the 40 percent green area, which may include paved areas such as sidewalks, that is required in CPDs. Open space requirements in other zones, such as the 30 percent open space requirement in the I-3 Zone, can also include paved area.

The environmental benefits of providing the pervious landscaped area is related to the quality of the pervious area. The benefit that the City would most like to see is the shading of parking lot areas, which would mean that the landscaped area would mostly be provided as trees in the parking lot area, as opposed to perimeter landscaping. Although landscaping is important from an aesthetic perspective, the most environmental benefit can be derived from a reduction in the heat island effect associated with open parking lots and the resulting temperature decrease for stormwater runoff.

Recommendation:

Staff therefore recommends that a minimum of 20 percent of office sites be provided as landscaped pervious area, with the priority being treed areas in parking lots. The recommended language, shown in italics, is as follows:

Section 25-648 Modification of parking, access and loading requirements

(1) For the entire comprehensive planned development, but not necessarily for each building, not less than forty-five (45) percent of all off-street parking spaces for office uses shall be located underground or in parking structures. This may be reduced to twenty-five (25) percent if approved as part of approval of a comprehensive planned development, where the property subject to the comprehensive planned development is adjacent to or crossed by an existing or proposed transitway. This subsection shall not apply to CPD applications approved after December 1, 1999.

Section 25-649 Modification of screening and landscaping requirements

b. ...

c. ...

d. The design plan submitted at the detailed application review stage for each office site containing office or including research and development uses shall provide a minimum of 20 percent of the office site area as pervious vegetative landscaping, such as grass, trees, hedges, vines, ground cover, and flowers. The design plans shall provide for distribution of tree cover and other landscaping in parking lots in order to accomplish shading of parking lot areas. This subsection shall only apply to comprehensive planned developments approved after December 1, 1999.

Staff has discussed the implications of this requirement with the applicant, and their designers have tested it on specific sites. It appears that this requirement should be feasible.

/rjw