Tools & Techniques>Zoning Techniques

Zoning Techniques for Farmland Preservation
The following information was adapted from "Watershed Resource Papers" developed for the Dowagiac River Watershed Project by Langworthy, Strader, LeBlanc, & Associates, Inc.

Exclusive Use Zoning
Sliding Scale Zoning
Quarter/Quarter Zoning
Large Lot Zoning
Open Space (Cluster) Development
Agricultural Buffers

Exclusive Use Zoning

Exclusive use zoning, in this case for agriculture, can be an effective way to protect farmland from conversion to other uses. Exclusive use zoning is most appropriate where there is limited pressure for residential development and there are already existing large areas of prime or unique agricultural resources.

The purposes of an exclusive agricultural zone may include:

* protecting productive farms;
* avoiding conflicting land uses;
* maintaining a viable agricultural economic base; and
* maintaining open space/rural character.

New non-farm residences are often strictly regulated in the Exclusive Use District, including approvals only through a Special Land Use process. Site development standards within the District could include a maximum lot area for non-farm, residential use, and unless otherwise provided for, a large minimum lot area for a farm dwelling unit. Other provisions might include a maximum lot to depth ratio of 1:3 and large minimum lot widths and setbacks.

Sliding Scale Zoning

Sliding scale zoning limits the number of times that a parent parcel (a parcel existing on the date of ordinance adoption) can be split, based on its size, i.e., the larger the parcel the more splits that may occur, up to a maximum number established (as shown on the example chart). A larger minimum parcel size is also established.

Unlike exclusive use zoning, sliding scale zoning allows some non-farm residential development without special land use or other reviews. Sliding scale zoning can be useful in agricultural areas where there are significant development pressures and land speculation. The use of sliding scale zoning is most effective in areas where a wide range of parcel sizes exist and non-farm residential development has already begun to occur.

Minimum and maximum building lot sizes can be used to encourage the location of non-farm development on less productive farmland and/or in areas where development is more concentrated to direct growth onto already fragmented land. The use of buffer areas (see later discussion) is highly recommended to avoid land use conflicts between new residential development and agriculture fields.
Since this method does permit some use of land for non-agricultural uses, it allows communities to more effectively avoid a claim that land has been "taken" without compensation.

Quarter/Quarter Zoning

Quarter/quarter zoning is a density based zoning technique which is most appropriate in rural areas with large farming operations, moderate growth pressures, and where average parcel sizes generally exceed 40 acres. "Quarter/quarter zoning" refers to a quarter of a quarter section of land (1/16 of 640 acres, or 40 acres) where a limited number of non-farm homes are allowed for every 40-acres of land.

The non-farm splits are usually regulated by minimum and maximum sizes, e.g., no less than 1 acre and not greater than 2 acres. They are often required to be contiguous to one another to avoid breaking up farmland into smaller or odd-shaped sizes.

A variation of this method is to establish a density of homes within each section of land. Once that density is reached, further residential or other development is prohibited.

Large Lot Zoning

Large lot zoning simply increases the lot size required in residential zone districts where farming operations exist, except perhaps, where public utilities are/can be provided. Lot sizes are generally greater than 10 acres, depending on the objective (farmland preservation vs. rural character). In areas where farmland preservation is particularly important to the community individual lot sizes of 40 to 160 acres may be applicable.

Large lot zoning, however, is generally not considered to be effective in farmland protection since low density development patterns create parcel sizes which are "too big to mow, but to little to plow." In areas of marginal farming production this technique can have a detrimental effect by requiring large lots for individual homes and taking large parcels out of production for that purpose. This technique may be effective in maintaining rural character, but not farmland.

Open Space (Cluster) Development

Another approach to farmland preservation is to concentrate less on restricting development of property and work instead on the efficient use of land. Open Space Development (or as it is sometimes known, cluster development) provides for a denser concentration of development in a limited area, with no increase in the overall, or "gross density" of the site.

The object of clustering is not to increase the number of units developed, but to regulate the amount of land disturbed by structures, lawns, and drives. The gross density must still fall into the requirements of the Zoning Ordinance.

On larger parcels, the acreage not used in the development may be set aside for farming, provided that ownership or control of the area to be used for farming is firmly established. This development style permits areas of agricultural lands to remain in production, even as other parts of the property are developed for residential use.

Open space lands provided as part of an Open Space Development could be incorporated in a long-term lease agreement with a local farmer. Farm operators may also take advantage of this option by developing only a portion of the property to gain additional financial resources, while retaining the remainder for agricultural purposes.

Even where Open Space Development may have a limited impact on the preservation of farmland, it can allow for the preservation of many site features, such as wooded areas, steep slopes, wetlands, and other natural amenities.

Agricultural Buffers

Balancing the need to continue agricultural practices and the desire to develop land for non-agricultural purposes can be challenging. Open space buffers between active agricultural areas and other uses, such as residential development, can help reduce land use conflicts, particularly where residential and agricultural conflicts are occurring with greater frequency. The use of buffers can aid in easing land use conflicts and improving the relationship of agricultural uses and new residents.

Buffers are generally imposed on residential developments, rather than on farming operations, principally because the farm was probably the first use in place. Buffers should be sufficiently wide to protect the farming operation from lawn fertilizers, playing children, and other conflicts. At the same time, they cannot be so burdensome as to require excessive land commitments from residential property owners.

Buffers are most effective if a "no-disturb" zone is provided between residential properties and farmland. This requirement should be tied to subdivision, site condominium, planned unit development, or land division approval. It should also be required that the buffer be described in the property deed to alert potential buyers of the need to honor the no-disturb area.
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