Connecting Conservation Lands for Mutual Benefit

Located along the Tualatin River just south of Forest Grove, the 47-acre Maroon Ponds Natural Area is a rural site featuring a diverse mix of plant communities and habitat for many native wildlife species, including beavers, shorebirds and a variety of amphibians. 

Located within a half-mile of four other publicly owned natural areas, Maroon Ponds helps connect more than 4,000 acres of regionally important conservation lands for the benefit of water quality, wildlife and human health.

The natural area also sits at the crossroads of several important water infrastructure systems, including the point of diversion for much of Washington County's drinking and irrigation water. In addition to providing wildlife benefits and beauty, keeping Maroon Ponds in good ecological health also supports a supply of high-quality water for thousands of homes, businesses and agricultural producers.

The Site

First planting: 2015
Size: 47 acres
Stream length: 2,341 feet
Total to date: 117,922 plants
Plant communities: Emergent Marsh, Shrub Wetland, Forested Wetland, Oak Woodland, Riparian Forest, Upland Forest


The Challenge

Nature at Maroon Ponds was greatly compromised due to heavy human use and man-made infrastructure—from asphalt and debris to a dam that held back an old irrigation pond. Invasive vegetation and blocked connections to the Tualatin River also severely diminished natural processes at the site.


The Transformation

This site was purchased by Metro in 1995. Construction began in 2014. Working together, Metro and Clean Water Services (CWS) are restoring vital wetlands and forests at Maroon Ponds, as well as along the nearby margins of the Tualatin River. Over 5,000 cubic yards of man-made fill have been removed and safely disposed, including abandoned car parts, road debris and garbage. The restoration actions have dramatically improved the site’s natural hydrology, allowing three small creeks to flow through wetlands and reconnect with open water habitat on the Tualatin River floodplain and the Tualatin River itself. Annual monitoring for amphibians and turtles reveals that these species are making a comeback on the site while beavers have expanded their foraging into newly planted areas. 

The dense upland forest was thinned to allow a healthier mix of understory shrubs and native trees, including Oregon white oak and Pacific madrone. Living snags were created for cavity-nesting birds; dozens of acres were cleared of invasive species; over 1,000 pounds of native grass and wildflower seed were applied to newly exposed land; and more than 50,000 native trees and shrubs were planted to kick-start new forest habitat.

In addition to the thousands of plants installed on the site by the partners, nearly a dozen species of wetland plants emerged from the newly exposed mud in the bottom of the old pond once the dam was removed. These species include broadfruit bur-reed, dense spikerush, soft-stem bulrush, American brooklime and native willows. 

Tualatin Valley Irrigation District (TVID), Joint Water Commission (JWC) and Portland General Electric (PGE) also helped make this possible. TVID provided access through their property during construction; TVID and JWC worked with CWS to make sure the project met everyone’s needs; and PGE granted CWS access to enhance the creek that flows into the natural area from adjacent PGE-owned land.

Maroon Ponds is one of several upper Tualatin River sites restored to achieve landscape-scale change. When completed, it will offer exceptional foraging, breeding and wintering habitat for wildlife; natural floodplain storage; enhanced biodiversity; and increased protection for the river within the Tualatin Basin region.

The partnership between Metro and CWS leverages the agencies’ combined resources to further protect clean water in the Tualatin River watershed, reconnect floodplains and create healthy natural spaces.


93 native plant species
Plant cover change*

Native shrub/tree: +17%
Native herbaceous: +28%
Invasive: -41%

* Figures measure increase/decrease since monitoring began in 2013. Shrub/tree and herbaceous cover are measured only in plant communities appropriate to those species.

Maroon Ponds Natural Area: In Motion