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Issaquah, Washington

Issaquah, population 8,000, is located 18 miles east of downtown Seattle on I-90, the only interstate route heading east over the Cascade Mountain Range from Puget Sound. As reported in Beyond Takings and Givings, Issaquah and King County used the King County TDR program in March 2000 in a transaction that preserved a 313-acre sending area in King County and allowed an additional 500,000 square feet of floor area in an office complex within the City of Issaquah.

Issaquah uses TDR to preserve stream corridors and expand public open space within its city limits.

In 2003, the City began to explore the prospects for a TDR ordinance that could protect critical areas within the City. One year later, the City adopted a Comprehensive Plan amendment with the framework for a TDR program. In September 2005, the Issaquah City Council adopted a TDR ordinance as described below.

The Issaquah TDR ordinance lists five purposes for the program

  • Preserve land adjoining critical areas, particularly salmon habitat, riparian corridors and floodways.
  • Expand public open space areas.
  • Increase density in appropriate parts of the City and thereby increase the efficiency of transit and other urban services.
  • Promote adopted design standards.
  • Promote equity by allowing transfer of the development potential allowed to sending sites by existing regulations.

Sending sites within the City must meet at least one of the following criteria.

  • At least 30 percent of the site consists of critical areas or critical area buffers.
  • Site is contiguous with public open space.
  • Preservation of site would implement a Comprehensive Plan goal.
  • Site is adjacent to creek side restoration site.
  • Site requires a variance to be developed.
  • Site has limited access or infrastructure accessibility.

Sending sites outside the City must be in King County’s Rural or Resource zones and meet criteria specified in an interlocal agreement with King County.

Sending sites are mapped and designated as either first or second priority. Second priority sending sites may not participate until 50 percent of the first priority sites are certified. However, a landowner can request consideration of changing a second priority to a first priority site.

Receiving sites cannot consist of more than 50 percent critical area and must meet at least one of five sets of criteria regarding location, zoning and proximity to a transit center. The ordinance includes a provision for allowing sites to be added to the map of TDR Sending and Receiving Sites.

TDRs available to sending sites are calculated as follows.

  • For residential sites, the number of TDRs available for transfer equals the number of units that can be developed on that site.
  • For commercially zoned sites, one TDR is granted for each 2,000 square feet of floor area that can be developed on the site.
  • Each TDR allows the following distinct uses that can be combined on one receiving site but cannot be divided.
  • One dwelling unit.
  • One PM peak hour trip.
  • 2,000 square feet of impervious surface outside Critical Aquifer Recharge Area (CARA) or 1,000 square feet inside CARA.
  • 2,000 square feet of bonus floor area in some districts and 1,000 square feet in others.

The baseline density in receiving areas is the maximum allowed by the existing zoning. When TDR is used, the maximum density differs depending on the zone. Maximum density with TDR can reach 18 dwelling units per acre in two residential zones, 36 units per acre in another residential zone, a 25-percent increase in units in the remaining residential zones and a 25 percent increase in floor area in commercial zones.

In addition, the TDR ordinance establishes the building height bonus allowable when receiving area developers use TDR. For example, the maximum building height in the MF-M zone is 50 feet without TDR or 65 feet when the TDR option is used. Similarly, the ordinance sets forth maximum impervious surface limits permitted when receiving sites use TDR. For example, developments in the MF-M zone using the TDR option can exceed the baseline impervious surface ratio of 50 percent and cover either 65 percent or 75 percent of the site under the TDR option. Finally, the ordinance also includes a process for using TDRs to reduce PM peak hour trips within the City’s transportation concurrency review requirements.

In March of 2007, the City itself certified 25 TDRs on a property it had purchased with its general fund. One of the City’s TDRs was purchased by the developer of an office building for $50,000, making it the first receiving site to use the City’s new program.