1716 W MARINE VIEW DR BASE FILE 2018-01-02 MF Import

MEMORANDUM TO: Kirk Brooks FROM: Jane Zimmerman DATE: April 3, 1995 SUBJECT: Southeast Marina Project, Plan Review The Port is currently proposing to route the storm flow associated with the 6 month, 24-hour storm to the sanitary sewer, instead of providing on -site treatment of stormwater. Before the plans can be approved with this concept, the following must occur: - an interlocal agreement must be signed by the City and the Port agreeing to share in the cost of a predesign report to identify construction costs associated with routing a specified stormwater flow to the sanitary sewer; - after the predesign report is completed, a second interlocal agreement must be drafted and signed by both the City and the Port agreeing to share the costs associated with the upgrades. In addition, I have the following concerns: The information given for existing pipes and catch basins/manholes that would be affected by the changes downstream do not appear to be consistent (please see plans for specific structures, etc.) With the proposed design, many linear feet of existing storm pipe will be permanently full of water. The Port should be aware that sediment accumulation in these pipes may necessitate more frequent cleaning. Additional analysis regarding the possibility of river/tidal back-up into the sanitary sewer creeds to be performed. How often does the river/tidal elevation exceed the 12 foot elevation of the 24 inch connection between the new and existing manhole (a tide line of 12.1 feet is noted on the plans)? Is there a tide gate on the existing outfall that would prevent back-up into the sanitary sewer'?