Zoning Practice — April 2006

Ask the Author

Here are reader questions answered by David R. Godschalk, FAICP, author of the March 2006 Zoning Practice article "Buildout Analysis: A Valuable Planning and Hazard Mitigation Tool."

Question from Mark Zeigler, AICP, Associate Planner, City of Wilmington, North Carolina:

Our city is 90 percent built out with 10 percent vacant land left. Analysis of our recent future land-use plan from 2004 shows that the development trend has been to build at a much lower density than the code allows. Our city has vast amounts of low-density development with a large amount of residential land and not enough commercial and industrial.

1. As we rapidly approach buildout, can you think of development and redevelopment incentives or methods that we could offer commercial land owners to build at a greater density? (Note: We have a mixed-use zoning district available to developers. In my opinion, even a recent mixed-use development has been built at a too low a density.)

2. If we were to undertake further buildout analysis, do you know of trends and impacts from other cities that we would want to consider?

Answer from author David Godschalk:

In order to encourage higher-density commercial development and redevelopment, a city can consider three related approaches:

  1. carry out a buildout analysis to document the impacts of continued low-density development, as well as the benefits of higher-density, mixed-use development;
  2. build consensus on areas of change to higher density that are adopted in the future land-use plan;
  3. adopt zoning regulations that include both incentives and regulations to implement the desired type of development.

One of the most difficult challenges to achieving higher densities in a largely built-up city is the opposition to change from existing low-density property owners. Understandably, these existing owners desire to preserve land-use stability in their neighborhoods and feel threatened by the potential of development at higher density than currently exists. This is the problem that arose when Seattle attempted to implement its 1994 Sustainable Seattle Plan, which called for nodes of higher density to be achieved through redevelopment and infill in new urban villages. Opposition was fierce and well organized. The city then went through a number of years of neighborhood planning in order to respond to the concerns of existing residents and to generate agreements on adjustments to the proposed densities. Ultimately, they were able to work out a new higher-density land use pattern through a strong citizen participation program that empowered the neighborhoods.

This opposition is also a problem for developers, who realize that it is much less difficult to build at the same densities as existing properties. The delays caused by opposition and the conflicts generated by lawsuits tend to discourage developers from proposing new higher-density infill or redevelopment projects. It may be much easier, and possibly more profitable, for them to accept the existing low densities, even if the zoning allows higher densities.

If the city desires to use its dwindling supply of land for higher-density development, then it must look for ways to assure the existing property owners that their interests will be protected and to assure potential developers that they will find a positive reception to higher-density proposals. A buildout analysis can help to frame the problem by pointing out the impacts of continued low-density residential development on the small supply of available land. Such impacts could include lost opportunities to create mixed-use areas, less than optimal development in special areas (such as waterfronts), difficulty in encouraging affordable housing, failure to grow the city's tax base (and thus to be able to provide desired public facilities and amenities), and possibly increased sprawl outside the city boundaries.

Once the buildout analysis has documented the benefits and costs of continuing the existing development pattern versus changing in some areas to higher density, mixed use, then stakeholders need to work together to build consensus on areas where the status quo is to be preserved and areas where change is to be encouraged. For example, the development management strategy of Blueprint Denver is to designate and map Areas of Stability, where maintaining the existing character is most important, and Areas of Change, where investment in new building and alternative transportation can be integrated. Areas of change include major corridors and close-in neighborhoods where change is both logical and acceptable.

Neighborhood workshops and charrettes are useful tools to build agreement on areas of change through the preparation of small area plans. (See the Small Area Plans chapter in the 2006 fifth edition of Urban Land Use Planning.) In these small area settings, designers can translate two-dimensional land-use and zoning maps into three-dimensional building forms, streetscapes, and public open spaces. New Urbanist professionals are especially skilled at creating these images of desired built environments. For example, see the Stapleton Airport redevelopment plan in Denver. Once consensus has been achieved, the new plans can be formally adopted as part of the city's comprehensive plan.

To implement the new small area plans, it will be necessary to rethink those portions of the zoning ordinance that permit the continuation of low-density development in locations where change is desired. Several options can be considered. Incentives can be provided in the form of increased density (with increases limited to the agreed-upon plan densities) and reduced processing time (if the proposed project conforms to the adopted plan). Regulations can be written to ensure that projects meet minimum densities, minimum setbacks, and other design parameters. For example, the zoning code could include both minimum-density "floors" as well as maximum density "ceilings." A helpful reference is APA's Planning Advisory Report 526: Codifying New Urbanism.

There is no single panacea that will work to change a long-standing trend toward low-density residential dominance. However, a combination of tools and planning efforts can make a difference.

Question from Russell L. Lambert, AICP, Yuma County (Arizona) Department of Development Services:

As a planner tasked with updating county area plans (last update five years ago), I'm interested in the analysis tools you might recommend or ascribe to for updating the area plans. Pending new industrial development may occur with probable extension of electrical power lines and gasoline pipelines supporting a proposed refinery.

The county is largely a low-density rural/agricultural area in the low desert area, with the county seat having approximately 90,000 people, two other communities ranging from 10,000 to 20,000 (full time), with higher winter-time guest residents two to three times those numbers. The largest rural community where work is being initiated has a population of approximately 3,500. There are two or three other "satellite" communities of small size supporting the rural, agrarian lifestyle.

This proposed major new development (industrial and support-related activities) along an interstate corridor is located about five miles from the nearest incorporated community (of 3,500 noted earlier) and approximately 15 miles distant from the metropolitan area. The rural density pattern for the area has generally been large lots for farming activities with occasional farm residences. A current development pattern seems to be two- to five-acre parcels for rural home site development, but various proposals are being discussed to support "master planned developments." Significant areas of federal and state land holdings exist, but some of these may be transferred to private ownership for support development to the proposed industrial development center while protecting higher-quality agricultural lands.

Any assistance or guidance would be appreciated.

Answer from author David Godschalk:

Your situation has many of the same issues as other rural/agricultural areas facing major industrial growth, along with scattered rural home site development and the prospect of large-scale master planned development projects. How do you maintain the desired quality of life in the face of these land-use and development pattern changes? What are the likely impacts on farming, winter tourism, public services, and agrarian lifestyles? Are existing government policies and procedures adequate to manage the consequences of new types and scales of growth? These are difficult questions, particularly under growth pressure demands.

A buildout analysis can help to make decision makers aware of the potential consequences of alternative county development patterns, and can provide the basis for a creating a new desired vision, to be implemented through revised county area plans and related growth management tools. The process of conducting a buildout analysis also can highlight the impacts of industrial growth on an agrarian county and illustrate potential mitigation strategies. A rural county is particularly vulnerable during periods of discontinuous change because many of its traditional ways of making decisions and dealing with growth are no longer adequate, and the necessary new policies and procedures have not yet been adopted.

A buildout analysis has the benefit of being an objective analytical tool, rather than a prescriptive regulatory tool. Even conservative elected officials should be able to support an analytical process that objectively seeks to understand the effects of land-use changes. The buildout analysis process can also involve stakeholders from the various interest groups — agriculture, tourism, industry, development, and federal and state government agencies. A side benefit may be to heighten the countywide level of understanding of different policy and planning choices while improving communications and relationships among the various parties.

You will need maps of existing land use and of future land use allowed under your existing county area plans. If your county tax office has a GIS database, that will be a good starting point for a buildout analysis. The Mass GIS website illustrates the methodology for mapping and analyzing current land use and buildout land use. (See Mass GIS "Scope of Services for Buildout Analysis.")

Your buildout analysis might question the future impacts of existing development trends and what the county could be like under two basic scenarios:

Continuing Existing Trends

What are the consequences of continuing to develop two- to five-acre parcels for residences, in terms of land consumption, sprawl, conflicts with agriculture, water resources, and the like? What will the future land-use pattern of the county look like with such low density spread between the existing city and towns? Where will the future population be located? Will it be possible to provide adequate public services under this scenario?

What are the direct economic, environmental, and social consequences of building the new industrial center? What are its indirect consequences, in terms of potential induced development along its fringe (e.g., the Disney World effect)? What will be its impacts on traffic, air quality, demand for public services, housing, and the like? Where will the future work force be located?

Alternative Development Patterns

Are there locations where it might be advantageous to encourage higher-density, mixed-use, master-planned developments, in terms of feasibility of providing public services, lessened environmental impacts, and the like? If so, what would be the pros and cons of a buildout pattern that directed a percentage of the future county growth into such planned communities? How would they affect the existing urban areas, the agricultural areas, and the sensitive environmental areas?

Could industrial development be handled in some alternative fashion? Are there ways to locate or design the industrial center so as to reduce its potential negative impacts? Could it be linked to master-planned development so as to decrease worker commuting?

If you are successful in completing a buildout analysis, then you can use its findings and conclusions in updating your county area plans. For some examples of contemporary land-use and small area plans and plan-making approaches, see the 2006 fifth edition of Urban Land Use Planning.

Question from Kris Mago:

How did you address the "Compensatory Storage" issue in the build out analysis involving the flood zone(s)?

Answer from author David Godschalk:

According to the Mecklenburg County Floodplain Mapping Summary Report (October 1999), the following process was used to develop the new floodplain maps:

  1. The floodplain boundaries were updated to correct the FEMA floodplain maps from the 1970s. Flood elevations and floodplain boundaries were developed through computer modeling to simulate the effect of rainfall and runoff in a watershed. The models were calibrated using data from actual storms. Property owners along streams were interviewed to ensure accuracy of the models.

  2. To create the new FEMA floodplain maps, current land use was loaded into the computer models and the analysis was performed using various flood frequencies to establish regulatory flood elevations and areas (e.g., the 100-year flood). Then an encroachment analysis removed storage areas from each side of the floodplain until the original water surface elevation increased by a surcharge value of 0.5 feet. That determined the boundaries of the FEMA floodway, where any fill will require a variance by the local government and approval by FEMA.

  3. In order to take future land-use conditions into account, Mecklenburg County developed local Floodplain Land use Maps (FLUMs) that are more restrictive than the FEMA maps and will be used to regulate new development. They used existing land use and a 0.1-foot surcharge to establish the boundaries of the FLUM floodway. This set aside additional areas as floodway, increasing the carrying capacity of the floodplain, and reducing the amount of floodplain that can be filled and built upon. This information is used in regulating land development to limit the amount of fill placed in the floodplain. Fill in the FLUM floodway requires a variance by the local government, but not FEMA approval.

  4. In addition to increasing the size of the floodway, minimum finished floor elevations (FFEs) of new structures will be based on future, ultimate development in the watershed in order to protect new development from flooding. Future land use, defined as ultimate buildout in locally adopted district plans, is loaded into the hydrologic/hydraulic computer models. New flood elevations and floodplain areas are computed and used for all new building permits. New development must be constructed a minimum of one foot above the base flood elevation.

Question from Nimfa Simpson, AICP, City Planner, Xenia, Ohio:

What should be considered in a build out analysis? Can you provide us with a general outline?

Answer from author David Godschalk:

A buildout analysis should consider the impact of the future, ultimate development allowed in the planning area on the public health, safety, and welfare. This future growth scenario of full development projects the location and amount of growth allowed under existing community development plans and regulations. Thus, the buildout analysis should be designed to compare existing and projected future development, and then to consider the impacts of the change from present to future.

A general outline of a buildout analysis report typically would include the following sections, which also follow the typical steps in conducting a buildout analysis:

1. Purpose: states the objective of the analysis. For example, a community might be concerned about protecting the public from natural hazards, such as floods, as was the case in Charlotte Mecklenburg. Or it might be concerned about the adequacy of its public facilities, such as schools, water supply, waste disposal, etc., to support projected growth. Or it might be concerned about sustainability and livability in the future, such as the Massachusetts Statewide Buildout Analysis  Whatever the case, the purpose of the analysis should drive the analytical process and methodology.

2. Existing Development: describes the current status of development in the planning area. This would include verbal, tabular, and mapped information about existing land use, population, zoning, environmentally sensitive areas, natural hazard areas, and the like. It could identify areas of potential development, such as vacant or underdeveloped lands or possible redevelopment or infill areas.

3. Projected Development: describes the full amount of future development possible under existing regulations, policies, and plans. This would include verbal, tabular, and mapped information about the location, amount, and type of future land use and population. It could be stated as a single future buildout condition, as a time sequence of development leading to buildout, or as a set of alternative scenarios based on potential changes in plans or regulations (such as buildout under an Existing Policy scenario versus buildout under a Smart Growth scenario).

4. Buildout Impacts: discusses the projected impacts of buildout relative to the purpose of the analysis. This would include the sources of data employed, the mapping procedure, the calculation of yield, the use of multipliers, and the like. This is the Abottom line@ of the buildout analysis. Findings should be carefully framed to meet the needs of residents and decision makers, who must understand not only the analysis conclusions, but also the assumptions that underlie them.

5. Methodology: lays out the procedures and technical information used to create and analyze the buildout scenario. It is important to document the buildout analysis formulas, multipliers, and other quantitative techniques, so that the study can be readily updated and revised as conditions change. Collected data should be provided in technical appendices. Maps and GIS information should be provided in digital files.