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Tonquin Geologic Area goals and objectives

Planning and conservation    Natural areas, parks and trails    Protecting natural areas    Acquiring natural areas    Tonquin Geologic Area    Goals and objectives

Learn about the goals and objectives for habitat and water quality protection in the Tonquin Geologic Area target area. View maps illustrating the Metro Council's priorities in this area and learn more about the importance of the area to our region.

The Metro Council's goal and objectives for the Tonquin Geologic Area target area are:

photo of Tonquin Geologic Area target area


  • Protect unique geologic features that provide valuable wildlife habitat. Acquire additional lands needed for a future regional trail corridor connecting Wilsonville to Tualatin.


Tier I Objectives

  • Acquire lands within the Coffee Lake Creek and Rock Creek for completing restoration on Coffee Creek and on permanent protection of the unique geologic features.
  • Acquire lands within the Coffee Lake Creek and Rock Creek areas for regional trail connections.

Tier II Objectives

  • Acquire lands to protect unique geologic features within the Basalt Creek area.
  • Acquire land for the trail corridor, particularly along Hedges Creek, Basalt Creek and adjacent to Tonquin Road.

About the area

The Tonquin Geologic Area comprises approximately 17 square miles of land in Washington and Clackamas counties. The natural area extends from the communities of Tualatin and Sherwood south to Wilsonville. This area has a unique landscape with extensive evidence of the Bretz Floods (or Missoula Floods) that scoured the Columbia River Gorge and extended into the Willamette Valley multiple times between approximately 13,000 and 15,000 years ago. Receding floodwaters from these events left behind unique geologic formations such as kolk ponds and channels, basalt hummocks and knolls, which are still present throughout the area today. This landscape contains considerable and diverse plant, fish and wildlife habitat. Coffee Lake Creek originates in the Tualatin-Sherwood area and flows south through Wilsonville to the Willamette River. The wetland habitat along the creek supports many important species of migratory and residential wildlife and wetland plants.

The Ice Age Tonquin Trail is a regional trail envisioned to connect the Tualatin River Wildlife Refuge in Sherwood to the Willamette River and the Willamette River Greenway in Wilsonville. A second "Y" in the northern half of the trail would connect the Ice Age Tonquin Trail up to the city of Tualatin and join up with the Fanno Creek Greenway. A trail bridge has been constructed across the Tualatin River at this location, linking Tualatin to Tigard and Durham and eventually connecting Portland all the way to Wilsonville. A feasibility study for a trail alignment has been completed by regional and local government partners. Federal transportation funding will provide for the development of a master plan for the Ice Age Tonquin Trail beginning in 2007. A section of the trail running through the new "Villebois" neighborhood in Wilsonville will be built by the area's developers. Other landowners or developers in the area could also follow this example.

2006 Natural Areas Program bond description

Bearing visible marks left by the ancient floods that shaped our region, the area from Wilsonville to Sherwood and Tualatin is unique. Protection of the rocky outcrops that frame these former lake bottoms will provide wildlife habitat of considerable complexity and richness and preserve the area's rare geologic features. Within this area, a 12-mile trail corridor will connect nearby cities and the new town center of Villebois to regionally significant natural areas (e.g., Graham Oaks Natural Area, Tualatin River National Wildlife Refuge, Kolk Ponds, the Cedar Creek Greenway in Sherwood and the Willamette River Greenway). The corridor will also provide an important recreation and commuter connector from Wilsonville north to Tualatin.

1995 Natural Areas Program goals and accomplishments

  • Create a Tonquin Greenway and wildlife corridor connecting the Tualatin River National Wildlife Refuge in the north to the Willamette River in the south.
  • Preserve the remaining unique natural features, such as kolk ponds, in the Tonquin Geological Area, which were created by the Bretz (aka Missoula) floods.
  • Acquire the state-owned "Wilsonville Tract" for a future natural area.
  • Preserve riparian buffers and wetland areas in the Rock, Coffee and Mill Creek floodplains.

To date 487 acres have been acquired in the Tonquin Geologic Area, including the 250-acre Graham Oaks Natural Area and the 165-acre Coffee Lake Bottomlands, which provide valuable protection and potential corridors for a proposed regional trail through the area.

New focus for Metro's 2006 Natural Areas Program

Protect and preserve the area's rare geologic features, wetlands, ponds and riparian buffers. Secure additional sections of the 12- to 16-mile wildlife and trail corridor connecting the cities of Wilsonville, Sherwood and Tualatin and the Tualatin and Willamette rivers.

Field research and scientific data findings

  • The Tonquin Geologic Area supports high quality natural resources that are unique to the region.
  • Diverse habitat types (oak woodland, madrone woodland, ash and oak forested wetlands, emergent wetlands, rock outcrops and kolk ponds) exist within close proximity to each other offering excellent opportunities for wildlife and education.
  • The wetland habitats along Rock Creek and Coffee Lake Creek support many important species of migratory and residential wildlife and wetland plants.

Public input helps Metro Council set priorities

In September 2007 the Metro Council approved acquisition plans for each of the 27 regional target areas. The Metro Council established these priorities with the input of natural resource and land use experts, scientists, citizens and local land managers. More than 500 people attended eight community open houses to share their ideas with Metro Councilors. Nearly 1,000 people filled out questionnaires ranking their priorities and offering ideas for partnerships and other ways to stretch the public's investment. The acquisition plans include a map, goals and objectives for each target area.

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Natural Areas Program

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