Oregon Metro acquired and manages the 1260 acre Chehalem Ridge Natural Area in Washington County, Oregon for its natural resource and recreational values. Metro is responsible for restoring and maintaining the natural resources and wildlife habitat and has relied on Ecological Engineering for site restoration services on some of its properties. Metro contracted with Ecological Engineering to provide analysis and design services to document current conditions and restoration opportunities and constraints for an unnamed tributary to Harris Creek, within the Chehalem Ridge Natural Area. The primary objective was to provide technical direction for stream stabilization and restoration. The headwaters of the unnamed tributary are located on the 732-foot elevation Fern Hill located northeast of SW Sandstrom Road in Washington County, Oregon. The tributary has a drainage basin of approximately 122 acres above the project site. The stream channel had been relocated in the past to facilitate agricultural practices. The relocation steepened the channel and concentrated its flow resulting in severe incision. Mr. Gorman determined that the primary restoration opportunities included installation of channel grade control, increased channel roughness, reduction of channel side slopes, removal of the existing road crossing and culvert, filling in an existing agricultural pond (to reduce bull frog habitat), and reconnecting the channel to its floodplain. Based on the site hydrology and topography, Mr. Gorman recommended revegetation of the lower site as an Oregon Ash/Slough Sedge forested wetland and the upper site as Oregon White Oak Savanna. All restoration opportunities and constraints were presented in a technical memorandum.
Stream Stabilization and Restoration
