The Town of Cary Land Use Plan

4.0 LAND SUPPLY AND DEMAND ANALYSIS

4.1 Introduction

Most growing towns and cities eventually confront the issue of the ultimate limits of their growth. This is the case for Cary, which has a finite supply of land into which it may expand. Cary is geographically land-locked, either by other municipalities or by topographical barriers. Cary is bounded to the north by Morrisville, Research Triangle Park, RDU International Airport, Durham County, and the City of Raleigh, to the east by Raleigh, and to the south by Apex, Holly Springs, and Fuquay-Varina, and to the west by Jordan Lake. Although not bounded by a municipality to the southeast, Cary is bounded by the Swift Creek Land Management Area. As mentioned in Chapter 1, Section 1.3, the Land Use Plan Study Area addressed by this Plan covers the entire geographic area that is available for possible future expansion, making it in effect a "buildout" plan for Cary.⁵

Yet, despite limits to Town expansion, there is an ample supply of developable land within the Planning Area -- certainly enough to meet Cary’s needs for the next twenty years. Nevertheless, it is crucial to understand these long-term limits to growth in order to manage developable land prudently, thus ensuring the long-term viability and sustainability of the community.

This chapter examines the supply of available land in the Land Use Plan Study Area, existing patterns of land consumption, and the anticipated future demand for land. The ultimate buildout population is also projected. This chapter does not, however, provide target dates for buildout or year-by-year population projections. Specific 5, 10, 15, and 20-year population projections are available in a separate publication from the Town of Cary’s Planning & Zoning Division.

For the purposes of this analysis, it is useful to consider land supply and demand within specific "subareas" of the Land Use Plan Study Area. The Plan Study Area consists of five separate "subareas," as described in Chapter 1, Section 1.3, namely:

• The area within Cary’s current town limits;
• The area within Cary’s Extraterritorial Planning Jurisdiction (ETJ);
• The areas in Cary’s Perimunicipal Planning Area (PPA);
• The Upper Middle Creek Study Area;
• The Chatham County Study Area.

For the land supply and demand analysis, the perimunicipal planning areas are categorized into
two subareas:⁶

• Perimunicipal areas west of Davis Drive;
• Perimunicipal areas east of Davis Drive and South of US1/64.

And, the Chatham County Study Area is considered as two subregions:

• Chatham County Study Area outside the municipal service boundary ("unserved"); ⁷
• Chatham County Study Area inside the municipal service boundary ("served").

And lastly, the Upper Middle Creek Study Area is also considered as two subareas:

• The portion of the Middle Creek Study Area south of Optimist Farm Road and designated as Very Low Density Residential, with an alternate use of Low-Density Cluster Residential (see Land Use Plan Map). (This area will be referred to as "unserved or cluster.")
• The remainder of the Middle Creek Study Area. (This area will be referred to as "served.")

The total area in these regions, and the total for the entire Land Use Plan Study Area, are as follows:

Table 4.1: Total Plan Areas (as of June 1996)

4.2 Existing Land Use Patterns and Land Supply

The existing pattern of land use is given by the following table (Table 4.2), which indicates the total acreage for different categories of land use, for each of the subareas.

Table 4.2: Acreage in Various Land Uses, by Subarea (as of June 1996)

For the purposes of this analysis, the supply of developable land is considered to be the total of the vacant land, plus the agricultural/forestry land and the residential estate land. Using these figures, the actual supply of developable land is as follows:

Table 4.3: Total Developable Land Supply, by Subarea

4.3 Future Land Demand

Future land demand is defined as the amount of land that the market will demand for each land use category over a certain time period. The time period of concern in this analysis is from the present day to that future date when the entire Plan Study Area is completely "built out," and all undeveloped land has been developed. (Note that this analysis does not consider the effects of possible future redevelopment of previously-developed land)

While it is impossible to precisely predict future patterns of land demand, reasonable estimates can be made based on prior experience and anticipated future land use trends and patterns, including those embodied in the Land Use Plan. Using the figures for total acreage by land use within today’s town limits (given in Table 4.2, above) and the official estimate of current population within those town limits, we can develop ratios that describe the number of acres of land that are required for each category of land use, for every 1,000 people. By using population and acreage data within the town limits, we can establish ratios that are typical of Cary’s past and current pattern of urbanization. Using these ratios, we can then estimate the future land use demands, by land use category, that can be expected for each 1,000-person increase in population.

Using this basic method, two possible future land use demand scenarios can be examined. In the first scenario, termed the Business as Usual Scenario, the future land demand ratios are constructed exactly as described above, with no alteration. The limitation in this method is that it assumes that future patterns of development will be roughly the same as past patterns in Cary. In the second scenario, termed the Compact Development Scenario, the future land demand ratios are modified to reflect changes in the anticipated character of future development. Specifically, for this scenario the ratios are mathematically modified to reflect the following future development assumptions:

1. 20 percent more land per capita will be demanded for office and industrial space, as Cary continues to evolve into a community with a greater share of regional employment.
   
2. 20 percent less land per capita will be needed for commercial development, as commercial development becomes more compact, with higher floor-area ratios and less parking.
   
3. While today almost 60 percent of all housing is low density (as defined in Table 4.2), in the future only 40 percent of all housing will be low density, both with an average density of 2.4 dwellings/acre.
   
4. While today about 19 percent of all housing in Cary is medium density (as defined in Table 4.2), with an average medium density of 4 dwellings/acre, about 30 percent of future housing will be medium density, with an average density of 4.5 dwellings/acre.
   
5. While today about 23 percent of all housing in Cary is high density (as defined in Table 4.2), with an average density of 9.6 dwellings/acre, about 30 percent of future housing will be high density, with an average density of 12 dwellings/acre.

Table 4.4 shows the ratios that are obtained based on this data:

Table 4.4: Land Demand Ratios by Land Use Category

Note that land demand ratios are not calculated for agriculture/forestry, vacant, or residential estate land, since these are the categories of land use being developed.

Using these ratios, we can estimate future land demand and the likely total population for Cary once all the available undeveloped land has been developed -- that is, at "buildout." The results of this analysis for the Business as Usual Scenario are given in Tables 4.5, 4.6, and 4.7. Table 4.5 shows the maximum population increase that can be supported in each of the serviceable portions of the Plan Study Area, and the future amounts of developed land, by land use category, that can be expected for that population increase. Table 4.6 shows the buildout population that can be expected in the unserviceable region of the Chatham County Study Area and in the Very Low Density Residential/Low Density Cluster Residential region of the Upper Middle Creek Study Area. Table 4.7 summarizes the population data from Tables 4.5 and 4.6, to arrive at a final total buildout population estimate for the Town, and for the entire Plan Study Area.

The results of a similar analysis for the Compact Development Scenario are given in Tables 4.8, 4.9, and 4.10.

Table 4.5: Future Land Demand in Serviceable Areas, under the Business as Usual Scenario

Table 4.6: Future Land Demand in Unserviceable Areas, under the Business as Usual Scenario

Table 4.7: Buildout Population Summary, under the Business as Usual Scenario

Table 4.8: Future Land Demand in Serviceable Areas, under the Compact Development Scenario

Table 4.9: Future Land Demand in Unserviceable Areas, under the Compact Development Scenario

Table 4.10: Buildout Population Summary, under the Compact Development Scenario

It can be seen in Table 4.7 that Cary would achieve buildout with a final population of approximately 200,600 if the future pattern of development mirrors the past. Table 4.10 shows that with the more compact future development pattern, an ultimate population of about 214,900 could be accommodated in the same land area.

It is interesting to observe the magnitude of the effect that average residential densities have on both land use demand estimates and the estimated buildout population. For example, suppose the residential density assumptions of the Compact Development Scenario were modified as follows:

1. Assume that average densities for the low density residential category increases from its historical average of 2.4 units/acre, to 2.8 units/acre for future development.
   
2. Assume that average densities for the medium density residential category increases from its historical average of 4 units/acre, to 6 units/acre for future development.
   
3. Assume that average densities for the high density residential category increases from its historical average of 9.6 units/acre, to 16 units/acre for future development.

With no other changes in the assumptions of the Compact Development Scenario, the future land use demands and population predicted for the scenario would now be those given in Tables 4.11, 4.12, and 4.13, below. As indicated in Table 4.13, an ultimate Town population of about 230,200 could now be accommodated at buildout. While there is a substantial range between the buildout population of 200,600 given at the low end by the Business as Usual Scenario, and the figure of 230,200 given by the modified Compact Development Scenario, the three estimates taken together provide a useful indication of the ultimate limits of Cary’s population growth. The scenarios also offer valuable insight as to how Cary’s overall future demand for land for various uses might vary in response to changing development patterns.

Table 4.11: Future Land Demand in Serviceable Areas, under the modified Compact Development Scenario

Table 4.12: Future Land Demand in Unserviceable Areas, under the modified Compact Development Scenario

Table 4.13: Buildout Population Summary, under the modified Compact Development Scenario

4.4 Analysis and Implications

Analysis of the land supply and demand figures both on their own and in conjunction with the Growth Plan Map yields the following findings:

1. Middle Creek and the southern PPA are rapidly urbanizing. Out of a total area of 2,230 acres in the PPA south of US1, only 1,039 acres remain for future development -- over 50% of the area has already been developed. And, out of a total area of 5,664 acres in the Upper Middle Creek Study Area, 1,672 acres have already been developed, leaving 3,992 acres for future development. However, of those 3,992 remaining acres, 1,151 acres lie south of Optimist Farm Road in an area designated in this Plan for either Very Low Density Residential or Low Density Cluster Residential uses (these uses are defined in Chapter 6). It is perhaps indicative of the strong growth pressures in this region that this rapid urbanization has occurred even though the area is under County jurisdiction, beyond the current Cary town limits and municipal services.
   
2. The Plan’s land use designations supply adequate amounts of land in all land use categories. However, over twice as much Office and Office/Industrial land is designated on the Map as projected to be demanded. This is not, however, either an unexpected or undesirable result. The finding is not unexpected because the ratios used to project future office and industrial demand are largely based on existing patterns, which are unusually low for a town of Cary’s size, and reflect Cary’s very large existing residential base. As Cary matures and continues to attract an increasingly larger share of regional employment, it is likely that the ratio of office and industrial land per capita will rise significantly, yielding larger demand forecasts for office and industrial acreage.