The recent case of Williamson County, Tennessee, provides useful insight into how even well-meaning conservation development laws run the risk of unintended consequences if the land use planning focus is too myopic.  Focusing on the size of the pieces and creating artificial development boundaries in contrast to planning across the entire landscape– increases the likelihood of a distorted development footprint, thereby minimizing the benefits local jurisdictions can obtain by adding conservation development principles to its planning toolbox.

Williamson County, Tennessee – A Historical Rural County Facing Spillover Development Pressures from Nashville’s Booming Economy

Williamson County, Tennessee, sits just south of Nashville, Tennessee, as is part of the Nashville metropolitan area.  From 2015-2019, the Nashville metropolitan area had the fifth-highest population growth in the United States — at 9.6%.  It is expected that this trend will continue, especially with both Amazon and Facebook in the process of establishing a significant presence in the area.  Facebook is believed to be making a $750 million investment in a data center on the outskirts of Nashville.  Amazon is in the process of building two corporate office towers to house its Operations Center of Excellence, which is expected to create 5,000 new jobs in the area in what is the largest jobs deal in Tennessee’s history.  Williamson County currently has 226,000 residents, but due to the metropolitan area’s economic growth, its population is anticipated to add another 100,000 residents in just the next ten years.

Williamson County’s Land Use Plan’s Unintended Consequences

Unintended development patterns have arisen in Williamson County, notwithstanding the adoption of a land-use plan with the concept of conservation development a critical component.  In 2007, the county adopted a comprehensive land-use plan update.  As a quick refresher, comprehensive land use plans are formal policy documents adopted by local jurisdictions but implemented through zoning regulations, and other ordinances, laws, and actions.

A primary goal of Williamson County’s 2007 plan update was to encourage higher-density growth in suburban infill within a municipal growth boundary (MGB) while boosting conservation development projects outside of the MGB.  The 2007 plan update explicitly stated that “[g]rowth will generally be directed toward existing or planned service areas and pushed away from rural areas with rural levels of services.”

The 2007 plan update had two core tenets that revolved around the sprawl-inducing aspects of decentralized sewer systems:

  • No development could occur inside the MGB that utilized an alternative sewer system unless the land had been annexed into a city, and the development project is subject to the additional requirements of the city’s planning and land use regulation system.
  • Conservation development projects outside the MGB could utilize alternative sewer systems.

The 2007 plan update concurrently approved higher rural zoning density in unincorporated portions of one residential dwelling unit per acre instead of one residential dwelling unit per five acres — as initially proposed.  The combination of the preceding factors led to the unintended consequences of disproportionate growth in the rural area.  This occurred because developers skipped over undeveloped land within the MGB and instead focused on development projects in unincorporated rural areas they had previously not been able to develop using conservation design principles.

Recent Adoption of a new Comprehensive Land Use Plan was a Missed Opportunity

On March 12, 2020, Williamson County adopted a new land-use plan where the debate was cast in the far too common, but mistaken, “rural character preservation versus maximizing land value” dichotomy.  The county decided to down-zone the rural areas from one home per acre zoning to one home per five acres zoning.  Williamson County Planning Director Mike Matteson best captured the sentiment behind the change.  Matteson stated that the 2007 land use plan conflicted with the county’s vision for rural preservation because there was a “disconnect between the [2007] plan and the county’s ability to implement the plan’s central theme of preserving rural character.”  The down-zoning debate sharply divided local citizens.  Those in favor of retaining the current one residence per acre zoning argued that down-zoning would decrease rural property owners’ land values because of the lower density allowance for new homes.  Those in favor of the down-zoning argued it was necessary to control growth and preserve the rural character of the impacted areas.

Rural Preservation vs. Land Value is not a Zero-Sum Game

My critique of Williamson County’s approach to updating its comprehensive plan is that it approached the unintended consequences of the 2007 approval of one dwelling per acre incorrectly.  The debate should not have been between five acres and one acre.  Instead, the discussion should have focused on larger-scale comprehensive conservation planning on private lands that identifies the best natural resource areas to protect and then envision the best spatial configuration to accommodate future growth.  Once that is determined, strategic placement of housing developments and well-coordinated open space stewardship can occur where both the preserved open space and the housing development serve as complementary functional parts of protected area networks.  The appropriate housing density, be it one dwelling per acre, one dwelling per five acres, something in between, or a combination of the preceding, would then be based on how the pieces best configured with the strategically set and coordinated large-scale landscape-based plan.  Such an approach, if done correctly, can enhance land values in the long-term, while also preserving the natural and rural character of areas like Williamson County.  An informative academic article on the concept of strategic placement of housing developments and the coordination and stewardship of open spaces is a 2015 article in Landscape and Urban Planning entitled “Balancing housing growth and land conservation: Conservation development preserves private lands near protected areas.”