Agenda - Planning Commission - 04/07/2011

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1.00 0.80 0.60 0.40 0.20 0.00 ILLUSTRATIVE 4 YIELD CURVES, RURAL a � Gre ,�,e The control measures are generally de- fined as follows (see Illustrative 5): 0 Green space refers to pervious surfaces that may include common spaces, such as nature reserves, conservation areas, and parks or other open spaces. In the rural and sub -urban classes they also relate to private, on -lot green spaces. Green space also refers to green mass representing the relative volume of vegetation. In a sub -urban context, green mass should exceed building mass. In an urban context, green mass may "tip the scales" to a subur- ban character. In the community character system, green space is defined by an open space ratio or, for nonresidential uses, a land- scape surface ratio. ®n Units Per Acre % Open Space R %n 0.48 ILLUSTRATIVE 5 APPLICATION OF MEASURES ® A development with a combination of density and open space that falls anywhere along the yield curve is of a rural character. ® Grayspace relates to the impervious area of a lot ortract, generally those consumed by parking and loading areas, as well as the building footprint. In relationship to character, the amount of on -site surface parking is a significant determinant, as is its relationship to the building and street(s). ® Buildings relate to both two and three - dimensional space. The amount of site area they consume and their relationship to other buildings, open spaces, and the street is among the factors that determine character. The height and mass of buildings are equally important as they relate to scale, building enclosure, and intensity. Pervious Cover Impervious Cover Street Spacing Open Space Using Community Character The dimensions and yields reflected below may be used to inventory and accurately categorize residential areas according to their character. By doing so, planners, public of- ficials, and neighborhood leaders alike may better understand what elements produce a certain character. This may be used to develop a land -use plan that is more definitive as to the intended character outcomes of individual areas and the community. Ultimately, these dimensions and measures may be used to cal- ibrate densities and open space percentages, establish dimensional standards, and deter- mine yields in creating regulatory provisions that relate to character. Ordinances that fail to achieve their intended outcomes are due to an overemphasis on land use and lot size, a lack of emphasis on site and building design, use of uniform setbacks and lot dimensions across districts, and unrelated standards for resource protection, among many others. Tipping Points Sometimes character is not easy to categorize, particularly when a neighborhood was built according to standards that, at the time, did not relate to character. In this way commu- nity character is a tool to ensure that future neighborhoods have an identifiable character. Specifying character is also made difficult by unique site conditions that create tipping points. These are tangible and intangible vari- ables that "tip the scales" from one character type to another. By way of example, what is an auto -urban neighborhood by reason of its street and lot layout and spacing may be classified suburban if there is significant open space; large, well- landscaped and treed front yards; and no garage or one situated to the rear or accessed via an alley. The most com- mon tipping points include: O Lot size and width, side yard setbacks, and building separation ® Front yard depth and amount of landscaping and green mass ® On- or off- street parking and front, rear, or alley- accessed garage • Percentage and distribution of common open space CHARACTER CLASS: RURAL Natural and agricultural character types are defined by their uses: wooded or savannah lands, plus creeks and wetlands for the natu- ral; crop and ranching, plus scattered, rural homesteads for the agricultural. Development within these areas is clearly accessory to the ZONINGPRACTICE 12.10 AMERICAN PLANNING ASSOCIATION I page 5