Final Environmental Impact Statement - New Federal Courthouse

New Search

Biological Resources Potential Mitigation Measures Because there would be no significant adverse impact on biological resources under Alternative l or 2, mitigation would not be required. However, landscaping could be designed to include open-space areas planted with native species that attract urban wildlife. Landscaping standards should take into consideration current and future maintenance needs, ensuring that selected trees have adequate room to grow and that their placement and their mature sizes add to the community's quality of life. Guidelines for landscaping and planting street trees should be followed to the extent feasible without compromising the strict security needed for a federal courthouse. Implementation of the following mitigation measures could help to avoid or minimize impacts on threatened and endangered fish species during construction and long-term operation of the proposed courthouse facility. Additional mitigation measures for minimizing impacts on fish are listed in the water resources section of this EIS. ^ Best management practices should be implemented during construction, and the contractor should prepare a temporary erosion and sedimentation control plan to prevent water quality impacts in the Willamette River. • The existing stormwater drainage system should be maintained until the new system is installed and functional. • Catch basins should be cleaned prior to and after construction activities take place. Sediments and pollutants should be removed from runoff prior to discharge to the catch basin (through the use of inserts for oil and sediments) to protect the drainage system until the project is completed. ^ Exposed soil should be covered with plastic sheeting during rain events to prevent erosion. • Exposed soils throughout the project area that are cleared should be hydroseeded, mulched, and matted as soon as possible after clearing or grading to minimize erosion potential. All cleared area should be revegetated after construction by planting native tree and shrub species, and hydroseeding. An emergency spill containment kit should be located onsite, and a pollution prevention plan should be prepared by the contractor to address prevention and cleanup of accidental spills. ^ Stormwater collection and treatment facilities should be constructed for ,_ the runoff generated by impervious surfaces created for the proposed ''' I courthouse. These facilities should meet local and state requirements for detention of stormwater. I' ~, Final EIS 60 New Federal Courthouse ~.,