Environmental Review Toolkit
Water, Wetlands, and Wildlife

flooded wetland
Flooding of the site due to releases at upstream dams, March 25, 2004. (ODOT)
Phase I wetlands at the end of the first growing season, September 14, 2005. (ODOT)
wetland and pond
Emergent Reference #2, near milepost 11.7, on State Highway 27. (ODOT)

Oregon Department of Transportation

Oregon's Ecosystem-Based Approach to Mitigation and Conservation Banking

The Oregon Department of Transportation (ODOT) needed to provide an efficient and effective program to mitigate unavoidable wetland impacts, improve environmental compliance efforts, create ecologically sound and sustainable mitigation, and conserve resources. On-site mitigation is frequently challenging to develop, not cost-effective and often results in little long-term ecological value. The ODOT Mitigation and Conservation Banking Program was initiated to streamline highway project permitting, reduce costs, and facilitate restoration of regional ecological priority habitats and recovery of threatened, endangered, and rare species.

Before jumping into mitigation banking, ODOT developed a set of performance standards to minimize impacts to wetlands and other aquatic resources. This helped satisfy Section 404 guideline requirements to minimize impacts to aquatic resources. For unavoidable impacts, the Banking Program provides a holistic and integrated approach focused on ecosystem recovery and lost habitat functions. Banking Program elements were developed collaboratively with input and participation from regulatory and resource agency partners. Prioritization of ecosystem conservation needs helps identify regionally significant mitigation alternatives that will contribute most to the recovery of habitats and species. The ODOT has been able to achieve cost-effective and ecologically meaningful mitigation by addressing these needs at ODOT bank sites. The Habitat Accounting Method helps to accurately measure ecological functions for better accounting of impacts and restoration efforts.

Lost River Mitigation Bank

So far, ODOT is developing three bank sites with multiple objectives. The first is the Lost River Site, near Klamath Falls. The Klamath Falls region has lost about 75 percent of its wetlands, thus this restoration project is important in restoring regional wetlands functions. To reestablish wetlands on the site ODOT focused on hydrology, conceiving a plan to mimic natural water fluctuations associated with the establishment of emergent wetlands. To reestablish the hard-stem bulrush (Scirpus acutus) wetlands that were there historically, ODOT excavated up to four feet from the degraded pasture along the edge of the Lost River to create a wetland bench. Because bulrush wetlands do not readily establish in water held at a constant level, the ODOT design provided water level control for the first growing season. Water from the site was intermittently pumped out. By the end of the first growing season, the wetland was fully vegetated.

The site has exceeded expectations. In addition to replacing functions that have been lost over the past century, the wetlands add to the scenic attraction of the area, serve as a refuge for the area's wildlife, and help to improve water quality in the Lost River. The site also provides an important resource for recreation: supporting bird watching, hunting, fishing, and wildlife watching. To assure long-term stewardship of the site, ODOT is partnering with local conservationists.

Crooked River Site

The ODOT is partnering with the City of Prineville to build the Crooked River Wetland Mitigation Bank. Approximately 30 acres of city property along a two-mile stretch of the Crooked River has been set aside for wetland and riparian improvements. The property will remain under Prineville's ownership; ODOT will establish the bank. The Crooked River Wetland Mitigation Bank will provide a high level of needed wetland functions in the Deschutes Basin.

Located in a degraded, low-lying area immediately adjacent to the river, the bank site lends itself to the establishment of wetland hydrology. As a result, wetlands currently exist on part of the site and have served as a reference for the bank.

Following the historic 1964 flood, the Crooked River was straightened, channelized, and the riparian vegetation removed. The river has been progressively down-cutting with higher velocity flows; resulting in erosion, loss of riparian habitat, and increased downstream flooding. Upstream dams on both the Crooked River and Ochoco Creek also contribute to alteration of the river system. Establishment of wetlands along the two-mile stretch of river owned by the City of Prineville will help to mitigate not only impacts associated with the area's future highway projects but also indirect impacts associated with future housing and commercial development of the central Oregon region.

Current and future beneficiaries of the site will include sensitive and federal ESA-listed species, including redband trout, Pacific lamprey, western toad, Oregon spotted frog, bald eagle, pallid bat, and long-eared myotis bat.

Medford Vernal Pool Bank

The most unique of the ODOT bank projects is a Vernal Pool Mitigation Bank (VPMB) near Medford, Oregon. The VPMB will focus on preserving and managing vernal pool complex habitat, one of the highest priorities for wetland resources and habitat conservation in the Klamath Mountains Ecoregion. This habitat has declined rapidly in southern Oregon as development pressures increase. Vernal pool complex is extremely rare and supports sensitive and endangered species. The greatest conservation need in Oregon occurs in and near the Agate Desert, approximately 8 miles north of Medford in Jackson County.

Vernal pools complexes are unique; characterized by shallow, seasonally-connected seasonal pools, swales, and sloughs in an upland matrix. The vernal pools of the Agate Desert are habitat for birds, amphibians, insects, and vernal pool fairy shrimp. Vernal pool fairy shrimp are native to vernal pool habitat in California and Oregon and were listed as threatened under the Federal ESA in 1994. Over 7,500 acres of vernal pools in the Agate Desert were federally-designated as critical habitat in 2003 and the Oregon Natural Heritage Information Center estimates that 23 percent of the original vernal pool topography and hydrology in the Agate Desert remains.

There is a clear preference for preservation of existing Agate Desert Vernal Pool Complex over other mitigation concepts because these systems are difficult to restore or create. Preservation could protect a unique wetland resource, with low risk of failure. This ecological preference would result in broad acceptance of VPMB mitigation acre-credits for permitted impacts. Therefore, VPMB credits might be used as preferred, out-of-kind mitigation for most types of wetland impacts within the Klamath Mountain Ecosystem.

The ODOT has hosted meetings and discussions with state and federal agency representatives, visited the proposed sites, and conducted analysis of potential bank sites. Several bank sites have been identified on privately owned parcels between 77 and 198 acres each. The potential bank sites have been classified as some of the highest quality remaining vernal pool habitat in southern Oregon. These sites are near the Whetstone Savannah Preserve (Registered Oregon Natural Heritage Resource), and provide essential habitat connectivity and improved habitat stability of the preserved resource. These sites were also identified as high priority conservation sites by the Oregon Department of Fish and Wildlife in the Oregon Conservation Strategy. The ODOT is planning to play an important role in preserving and protecting these unique and critical habitats, while obtaining significant mitigation credits for unavoidable wetland resource impacts.

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