Carroll County, population 168,447 (2019), is located 25 miles northwest of Baltimore and borders the State of Pennsylvania. Within the County, the Town of Windsor and the Village of Linwood are recognized as historically important. In addition, the County contains various mineral deposits including Wakefield Marble, an aggregate that is crushed and used to make building materials. There are three quarries and a cement manufacturer in Carroll County. However, even though mineral extraction was recognized as important to the local economy, land-use conflicts over resource recovery activities left quarry companies uncertain about whether or not to make long-term investments in the early 1990s.
In 1992, Carroll County adopted a Mineral Resources Plan designed to achieve several objectives. The Plan sought to minimize the adverse impact of mineral resource recovery activities on surrounding land uses and the environment in general. It also attempted to assure that disturbed land would be reclaimed to an environmentally sensitive and aesthetically pleasing condition. And, with the help of TDR, the Plan sought to protect important mineral resources from urban development. Applicable code sections were amended in 2009 and 2010 and as of 2020 are now in code section 155.090.
Sending sites are in areas with an overlay zoning designation of VRA, Viable Resource Area. A Viable Resource Area is underlain by a potentially recoverable mineral resource. New residential lots cannot be created in the VRA. Owners of land with the VRA overlay can cluster new lots on portions of the same property that do not have the VRA overlay. However, if clustering is not possible, the County allows these owners to transfer development rights. The Planning Commission determines the base number of development rights permitted on the sending site using the density allowed by the underlying zoning. This number multiplied by two establishes the number of TDRs available for transfer. This constitutes a two-to-one transfer ratio. Each approved development right is assigned a serial number. Before these rights can be transferred, the sending site owner must record a Transfer Development Rights Easement that permanently prevents residential development on the property.
The potential receiving sites are areas zoned R-10,000, R-20,000, and R-40,000, where cluster subdivisions can increase density at two TDRs for every ten lots.
A Deed of Transfer must be recorded when development rights are transferred. When TDRs are ultimately used in a receiving site project, a Transfer of Development Rights Extinguishment must also be recorded.
The TDR provisions have been used at least once, permanently preserving an 80-acre parcel.