Planning staff backs addition of 5-foot "Class C" buffer in landscape ordinance amendment

Ms. Hillman, a planning staff presenter, outlined proposed amendments to Article 12.8 of the zoning code that would add a new Class C buffer yard, 5 feet wide, with the same plant composition required for a Class A buffer but a reduced width. The package also creates a new exemptions and flexibilities section and sets conditions for when a Class C buffer may substitute for the current 20-foot Class B buffer for small lots.

The amendments would permit the Class C buffer as a substitute for a 20-foot Class B buffer on lots 7,500 square feet or smaller or 50 feet or less in lot width. When the Class C buffer abuts pavement within the development (for example, a driveway), up to 15 feet of that pavement width must be permeable as defined by engineering standards. Unlike Class A and B buffers, a Class C buffer could not be further reduced when a wall or fence is incorporated. Ms. Hillman said the city’s urban forester verified planting viability for the reduced width.

Staff said there is precedent in the code for an exemptions and flexibilities section (for example, off-street parking standards). One exemption in this package removes the automatic requirement for a 20-foot Class B buffer where a nonresidential district abuts a residential district if the use in the nonresidential district is exclusively residential and no greater than 35 feet in height. A separate stipulation would allow a 10-foot Class A buffer to substitute for a Class B buffer for residential development no taller than 45 feet. Staff emphasized the Class C substitution is tied to lot size or width and does not override principal use standards that explicitly require a Class B buffer in Article 9.

In response to questions, staff clarified that the 15-foot permeable requirement is in addition to the 5-foot buffer (i.e., it addresses pavement abutting the buffer) and that engineering classifications determine whether a surface is considered permeable. Joshua Freys, an engineering staff member referenced during the Q&A, said permeable surfaces would include pavers, gravel, and grass-pave options; planning staff noted that, in zoning practice, gravel or similar materials have sometimes been treated as 50% impervious and might not qualify for this requirement.

Ms. Hillman said staff reviewed locally intensive lots and found about 42 lots that met the criteria for possible use of the Class C buffer; most were very small vacant or existing residential lots where zoning did not align with current land use. Staff recommended approval of the proposed amendments, saying they facilitate development of exceptionally small lots while maintaining the landscape article’s purpose to protect biodiversity and limit stormwater impacts.

The case will proceed through the Planning Commission process; staff indicated they are available to answer further questions as the amendment is considered.