Item C: I-5 Franklin Proposed Interchange Project Update

Home Browse Search

ENGINEERING/ENVIRONMENTAL AND COST ANALYSIS: I-5 WILLAMETTE RIVER CROSSING/GLENWOOD FACILITY PLAN PHASE II Table 1 Engineering and Environmental Constraints and Impacts Summary Category Concept Name Engineering/Environmental Comments Constraints/Impacts 1Full Interchange: Park, river and wetland impacts with Most of interchange would be Diamond 1bridge piers for north ramps, supported by a series of bridges. transmission line impacts.High cost solution with natural environment impacts. Full Interchange: Similar to Diamond 1 with a larger Similar to Diamond 1, but higher Diamond 2 footprint and greater impacts cost and more natural and including impacts to industrial human/built environment impacts. parcels in southeast quadrant. Full Interchange: Park, river and wetland impacts Reduced impacts to natural Partial Cloverleaf minimized (relative to other Category environment than other Category 1 1 concepts), but introduces impacts concepts, with greater impacts to to Laurel Hill neighborhood and human/built environment. requires larger parcels of industrial land in southeast quadrant. Impacts to transmission lines on both sides of I-5. 2Partial Interchange: This is the north half of Diamond 1 Similar to Diamond 1, with on- and Partial Diamond with similar park, river and wetland off-ramps in the river. impacts with bridge piers and transmission line impacts Partial Interchange: Similar to Category 1 Partial Has fewer river/natural resource Partial Cloverleaf Cloverleaf concept with similar impacts than other partial impact to the Laurel Hill interchange forms. Has fewer built neighborhood and less impact to environment impacts than the industrial area in the southeast Category 1 Partial Cloverleaf form. quadrant due to elimination of ramps 3 Split Interchange: Similar constraints/impacts as Relatively few additional impacts Two ½ Diamonds Category 2 concepts, with the associated with the Glenwood addition of the Glenwood ramps that improvements. impact industrial area along the north/east side of the freeway. Split Interchange: Includes additional impacts from The terrain between Franklin Blvd. Connected collector/distributor (CD) roads and Glenwood rises and falls Diamonds between the split diamonds. CD steeply on both sides of the roads would impact the Laurel Hill freeway. Accurate topographic neighborhood and Laurel Grove data and the development of Cemetery, requiring retaining walls engineering drawings are and transmission line necessary to better assess impacts relocations/adjustments on both sides of freeway. 4 Glenwood The footprint of this alternative is The Glenwood interchange lies in Interchange more contained and avoids many of an area of steep terrain and is Diamond the potential impacts (river, rail, therefore less developed and has Laurel Hill neighborhood) of the other fewer natural resources (e.g., categories. There are potential waterways and wetlands). impacts to the cemetery and some impacts to transmission lines. Large retaining walls would be required. PDX\052200014 6