Ordinance No. 20513 - Laserfiche WebLink

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goals identified in that study (e.g. introduce fish spawning opportunities, install biofiltration to improve water quality, improve people /millrace interface, etc.) could be realized with the creation of the Millpond Swale element. Sanitary Sewer The existing sanitary sewer infrastructure throughout the Riverfront property is composed of private and public gravity -fed pipe systems. The majority of the existing private sanitary drainage system drains in a northwesterly direction, to a single point of connection to the receiving public sanitary sewer system. The receiving public sanitary sewer is a 12 -inch pipe located within an easement aligned with Mill Alley, located approximately 150 -feet south of 4th Avenue. This public sewer begins north of 3rd Avenue, extends to the south following the Mill Alley alignment, crosses under the railroad tracks, and then joins a public 15 -inch sewer located at the intersection of 6th Avenue and High. Much of the existing private sanitary sewer system conflicts with the block layout proposed with the Master Plan, and it is assumed the majority of the existing private system will be removed or abandoned. The existing public system along the Mill Alley alignment also conflicts with the proposed block layout between the proposed 5th Avenue Extension and the railroad. Accordingly, some public sanitary sewer relocation may be necessary in this area. The public sanitary sewer system within the vicinity of the Riverfront property generally flows south and east. The existing public sanitary sewer in Mill Alley alignment is the only known public sewer that extends north of the railroad tracks into the Riverfront property. Two other public sanitary sewers are available in close proximity to the Riverfront property, but terminate south of the railroad tracks. Those include a 15 -inch sewer located within Ferry Street east of the courthouse, and an 8 -inch sewer located within Hillyard Street near the existing railroad crossing. Connecting to the public sewers located south of the railroad tracks would require boring under the railroad tracks and a potentially lengthy permitting process with the railroad. The existing public sanitary sewer systems on and adjacent to the Riverfront property are expected to be sufficiently deep to provide drainage for the proposed development by gravity, and a pump station is not anticipated to be necessary. City engineering staff have identified several potential deficiencies with the existing public sanitary sewer located in the Mill Alley alignment. First, the pipe crossing under the railroad tracks is expected to be near the end of its design life and needs to be replaced. Second, there is a reduction in pipe diameter, from 12 -inch to 10 -inch, from the point where the sewer pipe crosses under the railroad tracks, to the point of connection with a 15 -inch pipe at the intersection of 6th Avenue and High Street. Because of those deficiencies, if the Riverfront development proposes to discharge sanitary drainage to the public sewer in Mill Alley, an upgrade of the existing public system, from the Railroad crossing at Mill Alley to the intersection of 6th Avenue and High Street, may be required. Water Utilities Existing public water supply is readily available through much of the Riverfront property. An existing looped water main is present within the property and could serve as starting point for public water system upgrades and extensions. The existing loop is fed from a 12 -inch main extending from the southeast corner of the Riverfront property, along the proposed Railroad Street Alignment, up to a location just southeast of the intersection of Railroad Street and Millrace Lane. This 12 -inch line connects with an 8 -inch main extending north, generally following the alignment of the proposed Ferry Lane, up to a point near the southwest corner of the EWEB Headquarters building. From there, the loop connects to an 8 -inch main that extends both northeast into 4th Avenue, and southeast along the Willamette River frontage (east of the proposed Restaurant Row). The 8 -inch main located adjacent to the river frontage completes the loop by connecting back to the 12 -inch main in Railroad Street just to the southeast of the Steam Plant. Public water mains are also present in 4th Avenue and High Street. Page 3 of 4