July 23, 2015

FYI: Work near bridge on Hwy 219

CPRD owns property near/under the bridge over Hwy. 219. This property is closed to the public at this time, but you may notice work going on there. ODOT and CPRD have cooperated on a mitigation project designed to offset the construction effects of the Bypass. This will include restoring CPRD’s property along the banks with native vegetation, and removing invasive plants. Here are details from ODOT.

Newberg-Dundee Bypass Project
Wetland, waters, and riparian mitigation memo

The Newberg-Dundee Bypass Project will construct a new section of state highway crossing over wetlands, waterways, and riparian buffers in the Chehalem Watershed (sub-unit of the larger Yamhill River Basin) in northeast Yamhill County. As required by the U.S. Army Corps of Engineers and the Oregon Department of State Lands, ODOT conducted an evaluation of the types of impacted wetlands/streams (Waters)/riparian areas, and their relative functions/values with the needs of the local watershed. Based on the evaluation, the watershed has lost wetlands through agricultural conversion, road construction, and urban fill. Waterways have been degraded from past accelerated erosion, removal of in-channel large woody debris, disconnection from flood plains, and the loss of the riparian woodlands.

Construction Mitigation construction has begun.

In cooperation between ODOT and CPRD, compensatory mitigation will offset the effects of the state highway project and aid in the recovery of valuable wetlands, aquatic habitats, stream/floodplain connectivity, water quality, and riparian functions, while developing a natural area for the local communities. The overall mitigation plan will establish 2.0-acres of freshwater wetlands, 0.15-acre of stream habitat, and approximately 40 acres of riparian buffer. The mitigation actions are designed to be compatible with adjacent residential properties by maintaining the rural setting.

All excavated material will be moved and stored in an appropriate upland setting on the CPRD property. ODOT will maintain the mitigation areas for a period of five years, which will mostly involve vegetation management (i.e. weed control, mowing, and replacement of dead vegetation). Per Regulatory requirements, the mitigation areas will be protected in perpetuity allowing the site to mature as a self-sustaining natural resource.

ODOT access to the mitigation areas will be provided through existing roads on the CPRD property. All planting stock will come from local nurseries specializing in native vegetation. All exposed soils will be seeded for erosion control purposes before the onset of fall rains.

Riparian Mitigation
Mitigation will also establish approximate 40‐acre riparian area within the 90-acre CPRD property by planting a diverse mixture of native woodland and prairie species found in the Willamette Valley. Invasive plants will be removed as part of the mitigation work. The riparian area will visually screen the adjacent private properties, while lessening the encroachment of human presence beyond the CPRD property.

Wetland Mitigation

Wetland Mitigation involves expanding a local water resource onto the CPRD property by lowering upland ground by 1 to 5 feet. Construction elevations are based on an adjacent reference site being a low point on the bottomland landscape. Design of the created wetland will ensure that current and new hydrology is balanced to avoid an increase in water levels on abutting lands. Once the earthwork is complete, seasonal hydrology will support native wetland emergent, shrub, and tree plantings.

Stream (Waters) Mitigation
The Waters Mitigation is directly tied to the Hess Creek in that a new side channel and flood plain will be constructed. Large woody debris (i.e. logs with or without rootwads) will be placed in the side channel to form “jams” of interlocking material. The structural features will improve habitat for fish, invertebrates, and terrestrial animal species. All large woody debris will be secured in a manner to limit movement from the mitigation area during storm events or peak runoff periods.

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