New Castle County, Delaware includes the City of Wilmington and is bounded by Pennsylvania on the north, Maryland on the west and the Delaware River on the east. The County adopted TDR provisions to preserve farmland and historic landmarks. This program is not profiled in Beyond Takings and Givings.

Despite its location near the I-95 Corridor, New Castle still has working farms like this one.

In addition to farmland, the New Castle TDR program is designed to preserve historic buildings.

Developers use the TDR provisions by applying to develop two non-contiguous properties as a single project. When applying to use this code provision, developers must submit the following calculations: 1) the base density of the receiving site; 2) the number of rights available for transfer from the sending site; and 3) the density proposed when the rights are transferred. To complete a transfer, a developer must record an open space easement on the sending property.

Development rights may be transferred between properties in the Suburban Reserve District and between properties in the Suburban District as long as both properties are in the same planning district. Transfers can also occur from the Suburban Reserve District to the Suburban District within the same planning district, (but not from the Suburban District to the Suburban Reserve District). To encourage the owners of the best farmland to transfer from the Suburban Reserve to the Suburban District, the County allows a bonus: the number of homes allowed per development right doubles when the transfer preserves Class I soils and increases by a factor of 1.3 when the transfer preserves Class II soils.

For historic preservation, rights may be transferred from any zoning district to any zoning district within the same planning district. The Historic Review Board must approve these transfers.

On receiving sites, these transfers allow a reduced on-site open space requirement. As shown in the table below, TDR does not affect maximum net density, meaning the number of dwelling units per acre of land in the net buildable area – that portion of the receiving parcel that is not required to be on-site open space. However, even though TDR does not permit increased maximum net density, it does allow increased maximum gross density because the TDR option reduces the on-site open space requirement, thereby increasing the size of the net buildable area, as illustrated in the following table.

A March 2012 article quotes David Culver, General Manager of New Castle County’s Land Use Department, explaining that since its adoption in 1998, the  TDR ordinance has only been used twice, resulting in the preservation of about 400 acres of farmland.