Mitigation Sites

Port of Portland manages several mitigation sites, which are designed to provide a number of benefits to wildlife and the community.
Mitigation Map
Mitigation BobcastMarsh

Bobcat Marsh Mitigation Bank

Background
The Hillsboro Airport Parallel Runway project is proposed to have 1.92 acres of wetland impact. The alignment of the new runway and taxiways could not completely avoid wetland impacts. To mitigate for these wetland impacts, and future impacts at the Hillsboro Airport, the Port entered into an agreement with Oregon Department of Transportation (ODOT), City of Hillsboro (City) and Clean Water Services (CWS) to develop a wetland mitigation bank. The 18-acre wetland mitigation bank known as Bobcat Marsh is on City of Hillsboro land on the 725-acre Jackson Bottoms Wetland Preserve (JBWP). Prior to implementation, the mitigation site contained several large mounds of material that were placed on agricultural fields that were drained in the 1920’s by a drainage ditch, known as the Jackson Slough.

Mitigation Plan
The goal of the mitigation project was to restore 4.52 acres of wetlands and enhance 11.14 acres of wetlands. The mitigation project removed 30,000 cubic yards of material and restored hydrology to the previously filled wetlands. Degraded wetlands were enhanced by increasing the hydroperiod and replacing the reed canarygrass dominated site with native plant species. A shallow, braided linear swale was created through the restored and enhanced wetlands and a portion of Jackson Slough was filled and rerouted to flow through the swale. The Bobcat Marsh mitigation bank is a riverine flow-through system and is hydrologically connected to the Tualatin River. The mitigation site is made up of a combination of forested, scrub-shrub and emergent wetlands. A portion of the bank (0.87 acres of wetland restoration) was completed by ODOT before the Port was involved in the project.

Status
The excavation and grading of the mitigation site occurred in 2010 and 2011. Following grading, the site was planted in the spring of 2011 and again 2012. Due to significant plant mortality and herbivory additional planting and seeding will occur in 2013. In addition, spot spraying throughout the year will continue to target invasive/non-native species. City of Hillsboro staff are responsible for maintaining and monitoring the site. The first year of monitoring occurred in 2012 and the first annual monitoring report was submitted to the regulatory agencies in January 2013.

Mitigation Map

Buffalo Street Site

Background
Mitigation Dragonfly The Port filled approximately 65 acres of wetland at the southwest quadrant of Portland International Airport in 1993. The majority of the required wetland mitigation took place at the Jewett Lake site. However, the permit also included upland and riparian mitigation planting at Buffalo Street (approximately 15.6 acres) and Elrod Road (approximately 10 acres). The Buffalo Street site is located on N.E. Buffalo Street west of N.E. 42nd Avenue and is surrounded on three sides by slough channels including the Columbia Slough and Buffalo Slough.

Mitigation Plan
The goal for the Buffalo Street site was to create connectivity between existing natural areas in the Columbia South Shore Plan District. The plan included enhancing the slough banks, riparian woodland, emergent wetland, and upland meadow habitat to provide cover to the slough and nesting habitat, food, and cover for a variety of terrestrial and avian species. The site was planted in 1994.

Status
Site monitoring has taken place since 1995. In 2003 the permitting agency, the Department of State Lands, signed off on the success of the site, relieving the Port of further vegetation monitoring. In 2000 the Port entered into an Intergovernmental Agreement with the City of Portland Bureau of Environmental Services to fund work on re-vegetating portions of the Columbia Slough owned by the Port including 2.3 acres of riparian habitat adjacent to the Columbia Slough at the Buffalo site. In 2007, the Port installed approximately 1,000 native trees and shrubs along the west fence line where Himalayan blackberry was removed. The now established buffer enhanced about 0.3 acres along the western edge of the site adjacent to a golf course. In 2013, the Columbia Slough Watershed Council used grant funding and volunteers to plant native trees and shrubs at top of bank along the Buffalo Slough. The Buffalo site provides a diversity of habitat for wildlife including wooded uplands, emergent and scrub-shrub wetland, meadow and forested riparian. Weed control of teasel, thistle and blackberry is ongoing.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

Elrod Road Site

Background
The Port filled approximately 65 acres of wetland at the southwest quadrant of Portland International Airport in 1993. The majority of the required wetland mitigation occurred at the Jewett Lake site on Government Island. However, the permit also included upland and riparian mitigation planting at Buffalo Street (approximately 15.6 acres) and Elrod Road (approximately 10 acres). The Elrod Road site is located at N.E. Elrod Road and N.E. 33rd Avenue. The site is bordered on two sides by the East Slough.

Mitigation Plan
Mitigation Red Frog The goal for the site was to create linkage or connectivity between existing natural areas in the Columbia South Shore Plan District. The plan included enhancing habitat surrounding a proposed water quality treatment facility to attract passerine birds, small mammals, and reptiles, while discouraging potential aviation hazards such as waterfowl. Approximately 10 acres of upland woodland were planted with deciduous and coniferous trees and shrubs in two locations, referred to as the north and south fields.

Status
Monitoring of the site has occurred since 1995. In 2003 the permitting agency, the Department of State Lands signed off on the success of the site, relieving the Port of further vegetation monitoring. In 2000 the Port entered into an Intergovernmental Agreement with the City of Portland Bureau of Environmental Services to fund work on re-vegetating portions of the Columbia Slough owned by the Port including a 1-acre area adjacent to a conveyance ditch at the Elrod site. Wildlife monitoring has documented more than 65 species of birds; notable species include belted kingfisher, American goldfinch, brown creeper, downy woodpecker, red-tailed hawk, killdeer, wood duck and western wood peewee. Other wildlife observed on the site include coyote, Townsend vole, garter snake and long-toed salamander. Weed control within and adjacent to the mitigation site is ongoing.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

Government Island Grass

Government Island Grassland

Background
Airport Futures was a collaborative effort between the Port, City of Portland, and the Portland-Vancouver metropolitan community to create an integrated long-range development plan for the Portland International Airport (PDX). One result of Airport Futures was an intergovernmental agreement between the City of Portland and the Port for natural resource mitigation. The Agreement requires that the Port mitigate for 300 acres of upland grassland resources in lieu of having four PDX properties (totaling approximately 268 acres) zoned as environmental overlays. The Agreement states that the first 50 acres of mitigation must occur in advance of any development on one or more of the four PDX properties identified in the Agreement. Future grassland mitigation on the island, above the initial 50 acres, would be triggered when development on the four properties is proposed to exceed 25 acres. The 300 acre grassland mitigation site is degraded and composed primarily of open weedy fields that are dominated by non-native and invasive species such as pasture grasses, Himalayan blackberry, Canada thistle, and teasel.

Mitigation Plan
The goal of the grassland mitigation project is to enhance the structure of grassland habitat on the island by replacing non-native and invasive vegetation with a mosaic of diverse native forbs and grasses which can support grassland associated wildlife and insect populations. The plant species will be selected to attract and maintain native pollinator species that are experiencing significant declines locally. The plantings will also be selected to provide the structure and function necessary to provide the habitat requirements for other grassland associated species. Two years of extensive site preparation will occur before the mitigation plan is implemented. Site preparation is necessary to control invasive species and non-native pasture grasses and to expose bare ground which will help facilitate seed germination.

Status
The Port began preparing the first 50 acre parcel on Government Island for grassland enhancement in fall 2010 with herbicide treatments on the blackberries along the edge of the site and limited spot spraying within the site. The site preparation work continued in 2011 but was limited to mowing the entire site in August and spraying the blackberries in the buffer and spot spraying as needed within the site in the fall of 2011. The entire site was mowed again in June, September, and October of 2012. The site was monitored in 2012 and the first annual monitoring report will be submitted to the City of Portland and the Community Advisory Committee in early 2013.

Jewett Lake

Jewett Lake

Background
The Port filled approximately 65 acres of wetland at the Southwest Quadrant of Portland International Airport in 1993. The majority of compensatory wetland mitigation occurred at the Jewett Lake site. The 427-acre Jewett Lake mitigation site, located on Government Island, was a shallow basin that had been connected to the Columbia River via a man-made channel. The channel allowed water to flow into the lake whenever river elevations exceeded 10.7 feet. However, water also flowed out of the lake when river levels dropped below this elevation, which resulted in the lake and wetlands drying in the summer. The mitigation plan was designed to increase water retention in the lake and enhance and restore adjacent wetlands.

Mitigation Plan
Mitigation Dragonfly The goal of the mitigation at Jewett Lake was to diversify winter waterfowl habitat because this was the primary wetland function lost at the southwest quadrant. Permit conditions required using a Habitat Evaluation Procedure (HEP) as the methodology for measuring mitigation success. Wildlife habitat conditions at both the southwest quadrant and Jewett Lake were documented in HEP analyses prior to filling and mitigation actions and again at Jewett Lake five years after construction. The mitigation plan called for installing a water control and fish exclusion structure to increase the water retention time in Jewett Lake, creating approximately 30 acres of wetland at Jewett Lake, replacing 149 Average Annual Habitat Units (AAHU) that had been lost at the southwest quadrant, and enhancing the remaining wetland and upland areas of the site through cattle exclusion and vegetation management.

Status
The final year of monitoring took place in 1999. A review of the site was conducted by re-evaluating the original "target year (TY) 5" HEP predictions with those calculated from data collected in 1999. The results demonstrated that the mitigation site had exceeded predictions with approximately 100 AAHU in excess of the TY 5 estimate. In addition, approximately 58 new wetland acres were created.

Related Link Mitigation Management Program Annual Report (pdf - 20 MB)

PIC E-Zone Enhancement Planting

Background
This project resulted from a Type II Environmental Review by the City of Portland in 1999 for removal of the Environmental Zone designation from 2.04 acres of drainageways located within the Columbia South Shore Plan District. These drainages were filled as a result of activities associated with the Cascade Station development. The mitigation includes sites located adjacent to a 2.5-acre Army Corps of Engineers wetland mitigation site that was constructed in 1989. The project is also adjacent to the 40-mile Loop Trail that parallels N.E. Alderwood Road at Portland International Center.

Mitigation Dragonfly This Environmental Review was linked to a second Type II Environmental Review in 1999 for impacts to the Environmental Zone from the construction of a bridge over the Columbia Slough. Mitigation consisted of re-vegetation of the E-zone transition area along the Columbia Slough where the slough crossed the project site.

Mitigation Plan
The areas chosen for enhancement consisted of emergent and scrub-shrub wetlands adjacent to small, artificial channels. Riparian and upland scrub shrub vegetation was already established in low densities, but there was extensive invasion of weedy species. Mitigation increased the density of plantings and implemented a weed management program to control invasive species.

Mitigation for impacts from the construction of a bridge over the Columbia Slough called for enhancement of the 50 foot transition zone on the north shore of the slough. This enhancement project was included as part of the Intergovernmental Agreement (IGA) with the Bureau of Environmental Services for Columbia Slough re-vegetation.

Status
Planting of the Environmental Zone site was completed in April 2000, and a total of 5,927 plants were installed. The Port met its 5 year permit obligation to monitor the Environmental Zone site by the end of 2005. The final monitoring which occurred during the summer of 2005 resulted in at least 80% plant survival with 100% aerial cover in some areas. The Port continues to manage and maintain the entire site, including the Army Corps of Engineers site, by controlling invasive species and encouraging native plant establishment.

Planting of the transition zone was incorporated into the Intergovernmental Agreement with the City of Portland’s Bureau of Environmental Services in March 2000. In July 2001 a total of 2945 plants were installed, including big leaf maple, red alder, Oregon ash, black cottonwood, vine maple and thimbleberry. BES monitored and maintained the plants for five years as specified in the IGA then the Port assumed management.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

Ramsey Lakes

Background
Mitigation Ramsey Lake A number of mitigation projects were identified in the 1988 "Cooperative Agreement" between agencies, which was brokered to "Establish a Rivergate development program and an acceptable mitigation program for wetland impacts." The agreement was between the Oregon Department of State Lands, the Oregon Department of Fish and Wildlife, the Environmental Protection Agency, the Army Corp of Engineers, the U.S. Fish and Wildlife Service and the Port of Portland. The Cooperative Agreement established mitigation obligations for the Port's planned development of the Rivergate Industrial area and included the establishment of Ramsey Lake wetlands. This agreement was superseded by the Rivergate Consent Decree signed on January 31, 2001.

Mitigation Plan
Ramsey Lakes wetlands consist of three separate ponds with a total of at least 16 acres of water surface area. Construction was completed in 1990 and material removed from the lakes was used for construction of adjacent fill dikes and/or islands, or used to enhance upland soil before planting. The wetland fringe and islands associated with the ponds were planted with native vegetation following construction.

Status
Formal monitoring was required for three years and was completed in 1993, but maintenance continues to control invasive species, which is a standard procedure for completed Port mitigation sites. Plantings installed along the western slope in 2001 have become established and provide a buffer from the railroad and adjacent property. On the east side of the lakes, the Port enhanced meadow habitat to provide potential nesting habitat for birds and reptiles. The meadow buffer, as it’s called, was mowed, disked, spot-sprayed and seeded with native species in 2003. The Port continues to control invasive species throughout the meadow.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

Randall

Randall Site

Background
Federal Aviation Administration (FAA) airport design standards require a 1,000-foot runway object-free area and runway safety area (RSA) beyond the ends of each runway. To meet these FAA requirements when the runway was extended and for the relocation of NW Evergreen Road, approximately 6.19 acres of wetlands (4.65 acres of jurisdictional wetlands) at Hillsboro Airport were impacted. Proposed mitigation for the unavoidable impacts to wetlands consisted of on-site creation of a new drainage channel to mitigate for 0.27 acre of impacts and off-site enhancement, restoration and creation on the Randall site to mitigate for wetland loss. The Randall site comprises 22.3 acres located on both sides of NW 334th Avenue in Cornelius. At the time of purchase in March 2001, the property comprised open fields that had been used as pasture for several decades, and included residential structures, a cattle pond, a drainage swale and native deciduous forest. Site preparation included the removal of all structures on the site, the abandonment of two water wells and the installation of 11 groundwater monitoring piezometers.

Mitigation Plan
The goal of mitigation was to restore, create and enhance wetland and riparian conditions in order to replace wetland functions and values lost as a result of the RSA expansion. The mitigation plan provides for 6.68 acres of enhanced wetland, 3.32 acres of created wetland and 1.82 acres of restored wetland area, for a total of 6.25 acres of wetland mitigation credit to compensate for the loss of 5.92 acres of wetlands. The objectives of the plan include restoring wetland hydrology, creating wetland forest and scrub-shrub habitat, enhancing wetland prairie and riparian areas along Dairy Creek, and enhancing and restoring upland habitat.

Status
Excavation and grading of the site was completed in November 2002 and planting was completed in March 2003. However, in 2006 Port mitigation staff identified a 1.4 acre wetland shortage that was corrected in the fall of 2007 by excavating a larger wetland area. The wetland shortfall and subsequent correction resulted in additional monitoring years to ensure the success and survival of plantings in the regraded area. The final monitoring report was submitted in 2012. The Port will continue to maintain the site for invasive species and seek habitat enhancement opportunities.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

Riverbank Sites

Background
The Port of Portland's Marine Operations section manages a wide variety of constructed and natural riverbanks, and has initiated a Riparian Zone Management Program to address conditions along the Willamette and Columbia Rivers in association with its other programs. A number of these projects involve vegetation enhancements or stabilization improvements and do not have mitigation permit requirements. These projects are managed entirely by Marine Operations Property Maintenance with natural resource guidance and regulatory monitoring provided by Mitigation staff.

The responsibility for design, permitting and other regulatory requirements of the Riparian Zone Management Program rests with Marine Operations staff. Maintenance of vegetation and control of invasive weed species are performed by the Port’s Marine Operations landscape maintenance crew in consultation with mitigation staff. Mitigation staff provide technical advice regarding plant species selection for vegetation diversity and wildlife value. Staff also monitor the sites for performance and compliance with the permits, provide guidance for adaptive management, and prepare monitoring reports for submittal to regulatory agencies or to guide future actions. The Port’s Marine Operations Landscape Maintenance Group continues to provide invasive species management as necessary to all of the Riverbank sites during and after the permit compliance period.

Mitigation Plan
Mitigation Berth503 Bank stabilization at Berth 503 was undertaken to repair damage caused by the flood of 1996 to the Willamette River frontage at Terminal 5. The total mitigation area, including the slope and greenway, is approximately 34,000 square feet. Final monitoring reports were submitted in 2001. The site no longer requires irrigation or weed control and tree and shrub cover is 100%.

Mitigation at Berth 607 was a result of impacts to surrounding habitat as a result of repairing two outfalls on the Columbia River that were heavily eroded. The permit required planting approximately 23,200 square feet (0.5 acre) with 1690 woody plants. Planting occurred over 0.7 acres and consisted of 2,560 native trees and shrubs. Plant survival exceeded 80% during the final monitoring year in 2004. The Berth 607 Honda Dock Improvements included widening the access ramp to Berth 607, repairing deteriorated pilings, removing creosote-treated dolphins, installing new steel dolphins and adjusting the ballast from the floating dock. Native planting was required due to construction-related bank disturbances within the Environmental Zone; 150 native trees and shrubs were installed in 2007. The final monitoring report was submitted in 2010 and survival exceeded 100% due to natural recruitment.

The project at Berth 408 involved stabilizing and replanting approximately 3,200 square feet (0.07 acre) of the Willamette riverbank at Terminal 4. The permits required installation of 53 (Army Corp of Engineers, Oregon Department of State Lands and Oregon Department of Environmental Quality) and 121 (City of Portland) woody plants. Final monitoring in 2004 indicated that plant survival exceeded the 80% required by permit.

The Toyota Riverbank Restoration site encompasses 11.2 acres of river frontage at Terminal 4 and included a regraded shoreline, new outfalls, stormwater containment and treatment swales, native riparian vegetation, anchored logs and a cellular confinement system to provide bank stabilization. This project required City, state and federal permits and was completed in 2003. A total of 541 trees and 11,791 shrubs were installed and over 2,000 lbs of native seed was applied. Final monitoring in 2006 indicated that plant survival exceeded 100% due to colonization by desirable recruited trees and shrubs.

The T-4, Pier 2 Rail Yard Improvements and Willamette Greenway site was established in 2007 as a result of rail yard improvements to the adjacent upland at Terminal 4 and to address soil contamination on the bank at Wheeler Bay. The 1,370 linear feet of Greenway was planted with 180 native trees and 850 native shrubs. The regraded Wheeler Bay slope was planted with 120 native trees and 210 native shrubs. The entire slope and Greenway was seeded with native grasses and forbs. Final monitoring took place in 2011 and indicated that plant survival exceeded Greenway standards.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

Jewett Lake

Background
This project is a result of a federal consent decree that settled a citizen lawsuit against the Port (Jones vs. Thorne et al.) and several other agencies. The consent decree was signed on January 31, 2001, and it specifies mitigation actions for wetland fills that occurred during the development of the Rivergate Industrial Park over the past 30 years. The consent decree supersedes several earlier mitigation projects.

Mitigation Plan
Mitigation Wapato The design results in the restoration and enhancement of approximately 43.7 acres of wetland and riparian habitat for native plants and wildlife in the Rivergate area. The goals of the mitigation are to increase or restore the following wetland functions: water storage capacity, thermoregulation, anadromous fish habitat, amphibian habitat, waterfowl habitat and native plant communities.

The mitigation plan is divided into eight discrete elements:

  1. Construction of an 8-foot-wide asphalt path under the Lombard Street bridge;
  2. North bank, Columbia Slough: removal of fill to native soils and native planting over a width of 150 feet between the Lombard Street bridge and the Columbia Slough rail bridge;
  3. South bank, Columbia Slough: removal of fill to native soils and native planting over a width of 50 feet between the Lombard Street bridge and the Columbia Slough rail bridge;
  4. Leadbetter Peninsula: removal of fill to native soil and native planting over a width of 125 feet around the eastern, southern and western boundaries of the peninsula;
  5. Ramsey Lake visual buffer of native shrubs and trees along a corridor at the top of slope west and north of the Ramsey Lake mitigation area;
  6. Ramsey Lake enhancement: removal of fill to 14 feet NGVD, construction of two meandering swales and native planting;
  7. Culvert removal east of the railroad bridge on the south side of the Columbia Slough;
  8. Construction of a segment of the 40-Mile Loop Trail from the rail bridge east to the Port’s property line, and mitigation for five acres of wetland impacts as a result of trail construction.

Status
All elements have been completed. Final monitoring occurred in 2009, irrigation was removed in 2011 and the site continues to be maintained and invasive species controlled seasonally.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

Mitigation Trip

TRIP Phase I Mitigation

Background
In 2007, the Port purchased the Reynolds Metals Corporation (RMC) property for redevelopment as the Troutdale Reynolds Industrial Park (TRIP). The redevelopment project embodies the concept of beneficial reuse of a large brownfield site, in particular a Superfund-designated cleanup site. Development of the site began in 2008 with the Phase I construction of the FedEx Ground automated package distribution center. This development encompassed approximately 142 acres, 8,500 linear feet of paved trail on top of the levee, a new road (NW Swigert Way), the relocation of approximately 1,670 linear feet of Salmon Creek and its tributaries to accommodate the future widening of Sundial Road, the construction of a new utility corridor and stormwater facilities for the new development. Phase I development impacted a total of 0.28 acre of a degraded wetland that was dominated by reed canarygrass and Himalayan blackberry and 0.53 acre of waters (Salmon Creek and two tributary ditches). Mitigation for Phase I consisted of 0.42 acre wetland creation at East Lake. The mitigation site also provides advanced mitigation (3.18 credits) for future Port development. First year monitoring began in 2010 and will continue through at least 2015, as required by Oregon Department of State Lands and the U.S. Army Corps of Engineers.

Mitigation Plan
The goals of the mitigation plan for TRIP Phase I include:

  • Establish a minimum 0.42 acre of created emergent and scrub-shrub wetland at East Lake (1.5:1 ratio);
  • Improve wildlife habitat by diversifying vegetation and installing large woody material and snags;
  • Establish wetland hydrology within the mitigation area;
  • Create native-dominated wetland community within the mitigation area;
  • Replace in-kind waters of the state (Salmon Creek and roadside ditch)

The completed wetland mitigation site includes planted 4:1 and 5:1 slopes, a hummock at 13 feet NGVD and two shallow swales excavated to approximately 8 feet NGVD. The slopes and wetland bottom were seeded with native species. Silts encountered during grading were stockpiled and used as a 4-6 inch amendment to the slopes. Five cottonwood trees were removed from the excavation area, cut into manageable pieces and stockpiled before excavation began. Eight habitat logs, two with root balls intact, were then placed in the wetland once grading was complete.

Status
The first year of a five-year required monitoring period was conducted in September of 2010 over the entire mitigation project area. In 2011, an extended period of inundation resulted in plant mortality and lack of recruitment – vegetation monitoring was not conducted. Year 3 monitoring occurred in September and October of 2012. Due to a continued lack of natural recruitment, the site was replanted with rooted stock in November 2012 in the hopes that rooted plants such as Douglas hawthorn, Oregon ash and native willows that are tolerant of wet conditions will establish. The site will be monitored for at least three more years.

Vanport Wetlands

Background
Miti Vanport The 90.5-acre Vanport Wetlands site is located west of Interstate 5 and south of the Expo Center in north Portland. This site provides compensatory mitigation for wetland impacts at several locations on Port property. Historically, the Vanport Wetlands site was part of the Columbia River floodplain; however precipitation and storm water runoff are now the sole sources of surface water. Flooding is controlled on the site by a water control structure and pump station, which is managed by the Multnomah County Drainage District (MCDD). At the time of purchase in 1999, approximately 62 acres of the property were wetlands dominated by reed canarygrass.

Mitigation Plan
The goal of the mitigation plan was to increase diversity of plant and wildlife habitat by establishing a native plant-dominated wetland with a surrounding scrub-shrub or forested buffer. The mitigation plan was designed to alter the site's hydrology by capturing precipitation during the rainy season and modifying the existing pumping/drainage regime to allow increased water depth within the wetland basin. This creates an open water habitat in the winter and spring months. The extended duration of inundation was used to stress and ultimately reduce the reed canarygrass so that native wetland species could become established. The design also incorporated a number of physical modifications to the site, including a low, earthen berm in the northern portion of the property to prevent the flooding of Expo Road and the site’s north ditch and reconfiguration of the central drainage channel to provide a meandering swale. The plan included plowing, seeding, and planting the wetland and enhancing adjacent upland and buffer habitats with native trees and shrubs.

Status
Physical modifications were completed in December 2001, and planting was completed in March 2003. In October 2001 the site was renamed Vanport Wetlands, and in November 2001 it won the Columbia Slough Watershed Council's Achievement Award. In 2004, the Port won the Oregon State Land Board Award for the Vanport Wetlands project.

Site modification, planting and increased flooding have resulted in approximately 65.5 acres of wetland habitat in the original central wetland. All of this acreage has now been used to meet the Port’s mitigation obligations from a number of projects. The final monitoring report was submitted in 2010; however maintenance and weed control, primarily for reed canarygrass, thistle, teasel, blackberry and nightshade, is ongoing. Since completing and meeting the regulatory compliance requirements, the Port has installed 450 native plants in an effort to replace an existing Himalayan blackberry fence line with a native buffer. The Port continues to look for habitat enhancement opportunities that will benefit wildlife at Vanport Wetlands.

Vanport Wetlands provides habitat for over 100 species of birds, many of which nest and raise young on the site during the breeding season. In 2005 the Port confirmed that yellow-headed blackbirds had successfully nested and fledged young – Vanport Wetlands may be the furthest west this species is known to breed in Oregon. Many mammals have been observed including small rodents, beaver, muskrat, coyote and black-tailed deer. Amphibian species that are frequently observed on the site include the Pacific treefrog, long-toed salamander and bullfrog; western painted turtles have been observed but do not appear to be resident.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

West Hayden Island

West Hayden Island

Background
The West Hayden Island mitigation site was the result of an alleged inadvertent fill in 1996 of 1.19 acres of wetland on West Hayden Island. The 2.26-acre constructed wetland is adjacent to an existing emergent wetland and cottonwood forest on the north side of West Hayden Island.

Mitigation Plan
The goal of the mitigation plan was to create 0.21 acres of wetland forest and 1.79 acres of wetland scrub-shrub habitat. The performance standards include 60% coverage of planted woody species or naturally recruited native woody species by the seventh year following construction in the created and restored, palustrine scrub-shrub and palustrine forested portions of the mitigation site.

Status
Construction of the site was completed in the spring of 2007. Maintenance activities include hand watering and weed control. The new wetland provides amphibian breeding and waterfowl habitat and is dominated by native wetland plant species. Vegetation monitoring began in 2008 and will continue through 2014 to meet the 7-year permit period requirement for this project.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

Mitigation Powerline

T-5 Powerline Site

Background
Jurisdictional wetlands at the Terminal 5 property were filled for development of a bulk-commodities marine terminal facility. The T-5 Powerline site was chosen for mitigation because it offered an opportunity to restore wetlands adjacent to the Willamette River and along a corridor that connected the river with Smith and Bybee Lakes Wetlands Natural Area. The mitigation site is located along the Willamette River at approximately river mile 3. Historically, it was part of a large wetland complex in the Ramsey Lake area and was filled with dredge material in the early 1940s.

Mitigation Plan
The goals for this site were to 1) restore wetland hydrology; 2) establish emergent, scrub-shrub and forested wetland; and 3) establish a buffer around the wetland area. Target wetland functions and values included 1) diversification of wildlife habitat and enhancement of the wildlife corridor between the Willamette River and the Columbia Slough; 2) increasing ecological integrity; and 3) protecting and increasing western painted turtle habitat. The regulatory requirements for the site included restoring 10.7 acres (7 emergent, 1 open water, 2.7 scrub-shrub) of wetland.

Status
The T-5 Powerline site was initially constructed as a 10.7-acre site in 1995. In 1996 and again in 1997, the section west of Time Oil Road was re-excavated in order to improve wetland hydrology. However, dry conditions during 1999 and 2000 further reduced the wetland footprint. A total of 10 monitoring wells were installed to evaluate groundwater levels on the western portion of the site, and information obtained indicated that adequate hydrology could not easily be achieved in the portion of the property closest to the river without jeopardizing the function of the existing wetlands. A modified design for restoring the wetlands was proposed in 2001, which allowed for the restoration of 2.6 acres east of Time Oil Road, re-excavation of approximately 4.4 acres west of Time Oil Road, and approximately 3.7 acres of restoration at the Vanport Wetlands site. This was accepted by the agencies, and restoration work was completed in 2003.

The performance criteria as specified in the permits for the section of the site located east of Time Oil Road were met in 2003. Monitoring of performance criteria west of Time Oil Road continued through 2007 when the mitigation project received regulatory compliance. Since 2003, wildlife observations on the site have included over 60 species of birds, three amphibian species, three species of reptiles (western painted turtle, common garter snake and western terrestrial garter snake), and 11 species of mammals.

A road-over-rail project located in the vicinity of the wildlife corridor facilitated an under-crossing tunnel for animals below Time Oil Road. The tunnel was completed in the spring of 2004. Motion sensor surveillance has captured numerous animals utilizing the passage from rodents to coyotes to reptiles. In the spring of 2007 the Port installed approximately 1000 new native shrubs along both sides of Time Oil Road. The plantings will enhance the wetland buffer while providing a natural barrier meant to direct wildlife towards the tunnel entrance and keep them off of the road.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)

West Wye

Background
West Wye The Port impacted a total of 1.3 acres of scrub-shrub, emergent and open-water wetlands adjacent to North Lombard Street along the Columbia Slough. This occurred during the expansion of rail capacity to provide more efficient rail service to industries in the southern portion of the Rivergate Industrial District. The West Wye mitigation site is located west of the impact area in the same drainage corridor and is immediately adjacent to the T-5 Powerline mitigation site.

Mitigation Plan
The goal of the mitigation plan was to restore wetland hydrology and increase wildlife habitat diversity by establishing 1.3 acres of wetland surrounding an existing 0.32 acre pond (Nursery Pond) and enhancing approximately 1.1 acres of surrounding upland habitat. This area is contiguous with the corridor that restores the connection between Smith and Bybee Lakes Wetlands Natural Area and the Willamette River.

Status
Miti Green Frog Site construction began in 1996 and was completed in 1997. The final-year monitoring report was submitted to the agencies in 2002, and it showed that overall survival of woody and herbaceous species was above the survival performance criterion. Approximately 70 species of plants, including 35 native plants, have been recorded from the site. The wetland provides valuable scrub-shrub habitat within this wildlife corridor for birds, mammals, amphibians and reptiles. The Port continues to inspect and manage the site to control invasive species such as Himalayan blackberry, poison hemlock and common tansy.

Related Link
Mitigation Management Program Annual Report (pdf - 20 MB)