Understanding the Spatial Pattern of Urbanization in Medina County, Ohio
June 2001
by Carmen Carrion and Dr.
Elena Irwin
Department of Agricultural,
Environmental, and Development Economics
Ohio State University
For publication in
TwineLine, Ohio Sea Grant newsletter
“Urban sprawl” is a term that has often been used to describe the pattern of land use changes in suburban and urban-rural fringe (or ex-urban) areas of the U.S. and in Ohio. While this term has many interpretations, the most common definitions describe urban sprawl as excessive spatial growth of cities, leapfrog development, in which the development pattern is scattered or fragmented, and excessive separation of land uses.
Urban sprawl affects water quality by increasing the rate of urban storm water pollution, which is the most rapidly increasing cause of nonpoint source pollution in Ohio. This pollution has negative impacts on the environmental quality of Ohio’s aquatic ecosystems, including Lake Erie’s tributaries and shoreline. Because urban storm water runoff is determined by the location of urban land relative to aquatic ecosystems, an understanding of the spatial pattern of land use conversion is particularly important.
With funding from Ohio Sea Grant, we are studying the spatial pattern of urbanization in Medina County, located in the Rocky River watershed (see Map 1). Our project consists of four phases: (1) describe the spatial pattern of urbanization that has occurred in Medina County over time, (2) statistically identify the main factors that are driving the spatial pattern of conversion of farmland, forests, and other undeveloped land to urban land, (3) predict changes in urbanization patterns under different policy scenarios and (4) draw conclusions regarding the costs and benefits of policies that are most likely to minimize urban storm water pollution.
This article reports on results from the first two phases of our project. The first phase consisted of using parcel-level land use change data from Medina County to construct historical snapshots of the land use pattern between 1956-1996 (see Map 2). We then used a variety of landscape measures to quantify different aspects of the spatial pattern for each of the land use maps. These measures were used to quantify the size, shape, and arrangement of four different land uses across Medina County: residential, commercial, industrial, and undeveloped (including agriculture and forests).
Between 1956 and 1996, the percentage of undeveloped land of the total county area decreased from 95 percent to 77 percent. The rate of this conversion increased in recent years, especially after 1976, from 1.3 percent in 1956 to 3.0 percent in 1996. The amount of land in residential use increased from less than 4 percent of the total county area in 1956 to 18 percent in 1996 and, as of 1996, 85 percent of the developed land was in a residential use.
This rapid growth has been accompanied with an increase in the fragmentation of both undeveloped and urban lands. Results from the application of several different landscape measures show that the location of residential development has been the primary cause of this fragmented land use pattern. Specifically, we find that (1) on average, forested and agricultural areas have become progressively smaller in size over time, while the number of separate “patches”[1] of forest and agriculture has increased; (2) larger undeveloped patches of land have become fragmented into smaller ones specifically due to intervening residential development; and (3) residential development has become less clustered over time, while commercial and industrial development have become more so.
In the second phase of the project, we used statistical techniques to identify some of the determinants of this pattern of residential development. We find that areas of low-density population are more likely to experience residential growth, but also that residential development is less likely to occur in completely rural areas. This implies that people prefer to live closer to existing urban areas, presumably because of the services and accessibility that these locations offer, but at the same time dislike higher density areas that may be characterized by congestion and other negative effects of urbanization. These opposing positive and negative effects of urban areas explain why residential development has spread out, rather than become more clustered, over time.
In performing the statistical analysis, we were particularly interested in how various government policies, such as land use zoning, have influenced this spatial pattern of growth. We find that the minimum size that a lot is zoned has a significant effect on the likelihood that it is converted to a residential land use. Specifically, land that is zoned with a minimum lot size of three acres or greater is less likely to be converted. This implies that larger minimum lot sizes have increased the dispersed pattern of residential development.
The results from the statistical analysis can be used to predict the probability of future residential land use conversion for those parcels that are still undeveloped, but that could be developed in the future. Map 3 illustrates the results of this prediction. In phases three and four of the project, we will use the results from the statistical analysis to predict changes in land use patterns under different policy scenarios, e.g. alternative zoning regulations. Lastly, we will use these results to draw implications about which policies may contain the future pace and pattern of urbanization in ways that reduce urban storm water pollution and minimize the adverse affects of development on the environmental quality of Lake Erie.
For more information about this Ohio Sea Grant funded
research, contact Dr. Irwin at 614.292.6449 or irwin.78@osu.edu
Map 2
