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<br />
<br />maximum allmvable density is four units per acrer the
<br />allowable density for 15 percent (15 acres) of the parcel
<br />would be just two units per acre. These subdivisions are
<br />further subject to open space and setback requirements,
<br />both of \vhich are mentioned below.
<br />
<br />Planned Unit Development
<br />A Planned Unit Development (PUD) is a land
<br />development project that is comprehensively planned as a
<br />single entity via a site plan. It permits mixtures of housing;
<br />types and land uses, flexibility in building siting, usable
<br />open spaces, and the preservation of natural features.
<br />PUDs emerged in the 19605 as an alternative to typical
<br />zoning and subdivision controls that, in some cases, ,"vere
<br />seen as inadequate in regulating large development,
<br />containing a mix of uses or housing types.
<br />The increased use of PUDs in the 19705 \vas also a
<br />reflection of a greater sensitivity to the environment.
<br />Most conventional subdivision development
<br />involves clearing a site of all ground cover and
<br />vegetation, and placing lots on nearly every portion.
<br />PUDs, like cluster development, allow for density
<br />transfers from the environmentally sensitive parts of the
<br />site to the buildable parts. Many large PUDs
<br />no,"\! feature ,"vetlands, lakes, ,"vooded stream corridors,
<br />and storm water retention basins as amenities.
<br />Local governments generally have adopted
<br />provisions for PUDs in their zoning ordinances. There is
<br />often a threshold of acres over ,"vhich the developer is
<br />ei ther required to go through the PUD process or is
<br />given the option of going the PUD route.
<br />There are a number of common provisions in PUD
<br />ordinances. For example, most start ,"vith a statement of
<br />purpose that contains broad generalizations about the
<br />value of good design and increased amenities, and the
<br />importance of protecting the environment and \vildlife
<br />habitats. This statement is followed by a list of
<br />permitted uses in the PUD. Minnetrista, Minnesota, for
<br />example, lists the follmving.
<br />
<br />Sec. 23-178. Permitted Uses
<br />
<br />Within a PUD, no land or building shall be used except
<br />for one of the follm\'ing uses:
<br />
<br />]. Those uses listed as permitted or conditional uses in
<br />the districts in which the development is proposed
<br />[For residential PUDs, this would include the range
<br />of allovvable housing types-single-family detached,
<br />tmvnhouses, multifamily etc.];
<br />
<br />2. Educational, religious, cultural, recreational, or
<br />commercial facilities that are designed or intended to
<br />serve the resident of the PUD;
<br />
<br />3. Uses appropriate to other zoning districts shall not
<br />occupy more than 15 percent of the rUD land area;
<br />
<br />4. PUDs allowing density increases shall not be
<br />allowed in areas where municipal sanitary sewer
<br />facilities arc not available except vvhere the [city]
<br />Council finds it in the interest of the community to
<br />protect and preserve unique physical features of the
<br />property, including vvetlands, steep slopes,
<br />woodlands, or other physical land features.
<br />
<br />PUD regulations also contain provisions for
<br />allowable density and density bonuses. Some PUD
<br />
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<br />
<br />ordinances, like cluster ordinances, do not permit the
<br />density to exceed vvhat is allowed for the site under
<br />conventional zoning. (Point 4 in the Minnetrista
<br />example above is an exception.)
<br />And there are requirements for open space. There are
<br />several schools of thought about what percentage of the
<br />gross site area should be set aside as common open
<br />space and about v\rhat can be counted as open space. In
<br />a few recent ordinances, unbuildable parts of the PUD
<br />are excluded from being considered common open
<br />space. These areas include vvetlands, beaches and
<br />dunes, very steep slopes, and the flood\"ray portion of
<br />flood hazard areas (Reed 1992). The zoning ordinance
<br />for Cherry Hill To,"vnship, New Jersey, for example,
<br />states that "In no event shall floodplain areas or any
<br />other ground that cannot be built upon because of
<br />ordinance or statute [restrictions] be counted as open
<br />space land for the purposes of complying ,"vith this
<br />section [of the ordinance]."
<br />Other communities view the open space requirement
<br />as a means by which sensitive lands can be set aside
<br />from development and therefore allow them to count
<br />towards the requirement. Ordinances in communities
<br />that allo\v unbuiJdable portions to count as open space
<br />vary as to \vhether water surfaces can count tovvard that
<br />requirement. In general, jurisdictions that allmv
<br />developers to count unbuildable land as open space will
<br />allow ,"vater surfaces to satisfy 20 to 30 percent of the
<br />total open space requirement (Reed 1992).
<br />Finally, PUD ordinances include development
<br />standards and parking and landscaping standards.
<br />Local policy makers vary widely in how detailed tney
<br />make these provisions. They must balance the issue of
<br />whether to make the standards very specific, which
<br />could squelch the opportunities for innovative design,
<br />or too vague, which might give the developer the
<br />impression that "anything goes" in that community. To
<br />balance these concerns, many communities have
<br />development standards for building height, setbacks,
<br />lot coverage, and the location of parking, with the
<br />understanding that some variations on these standards
<br />may be appropriate and that exact specifications for the
<br />development ,"viII arise from the negotiating process.
<br />The review and approval process for PUDs is essen-
<br />tially the same as the typical subdivision review.
<br />procedure. But, because PUD standards and specifica-
<br />tions are developed on a case-by-case basis, the process
<br />of negotiation between the developer and local officials
<br />can go on far longer than it does for a conventional
<br />subdivision revie\v. It is a fact of life that, at present,
<br />developers who are "villing to be innovative with
<br />development design-such as \vith cluster develop-
<br />ments-are subject to greater scrutiny in the revie\v
<br />process than are those that arc proposing cookie-cutter
<br />subdivisions that do not necessarily respect the natural
<br />features of the site.
<br />
<br />Open Space Requirements in Subdivisions
<br />All subdivision ordinances contain minimum
<br />requirements for common open space above what is
<br />called for in yards and buffers. Communities use a
<br />variety of methods to calculate hm\' much open space
<br />the developer is required to dedicate. The most
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