2010/03/31 Council Agenda Packet

The intersection of the regional Riverfront Trail with the Simpson Pad access road is an important node in the site's circulation system. It is the point of entry to the residential development, and also a critical change in the characteristic trail standard along the length of the regional trail: the shared-use, separated trail of the riverfront converts to on-street bicycle lanes and sidewalks. The Simpson Pad entry offers the opportunity to create a significant gateway, one that helps to define the Riverfront District and denotes the changes in land use and trail character. This circulation node should be a point at which all traffic slows and pedestrians and bicycles are given priority. Boardwalk segments of the Riverfront Development trail system are proposed at the south and north ends of the Wetland C riverfront, as well as a connecting link of boardwalks or bridges over the central wetland (Weiland C), between the Simpson Pad entry and the Railroad Corridor Trail. The looped riverside boardwalks will offer wetland and river views as well as interpretive opportunities. The Railroad Corridor Trail is shown as a long, largely straight segment of trail along the former BNSF right-of-way, between Wetland C and the Landfill site slope. It is recommended that grades up the slope to the private developer's retail district be made gentle enough and visually inviting, to enhance the physical connection between the public and private areas as well as provide universal accessibility. The Railroad Corridor Trail will be developed to accommodate multimodal use like that of the regional trail, but will also provide for regular maintenance vehicle access. The leachate collection system for the landfill, the sheetpile wall for groundwater cutoff, site storm water and sewer collection facilities, and a relocated PUD transmission tower are all in this corridor. Construction of the Railroad Corridor Trail must thus accommodate the various weights, widths, and turning radii of service vehicles ranging in size from small pickup trucks to large utility vehicles. Early conceptual plans for this corridor envisioned a more curvilinear trail alignment than the one shown here, with multiple bridge and boardwalk crossings of enhanced and created wetlands. The Public Amenities Master Plan proposal of two linked systems, the wide, linear paved trail and the narrow, curvilinear bridge-and-boardwalk trail segments, evolved in response to multiple factors: the timing and coordination of various private developer and city projects along the length of the Railroad Corridor; the need to provide short-term construction and long-term maintenance access; the configuration of multiple environmental mitigation and enhancement projects; and the need for cost-effective trail construction and maintenance. .tet ;7 :. ' k _ Railroad Corridor-Trail alignment looking north from 41St Street. Single tracks left, double tracks right. Riverfront Development Public Amenities Master Plan 35 70