Laserfiche WebLink
1 <br /> 1 5. DOWNSTREAM ANALYSIS <br /> The City of Everett has stated that the existing 12" clay tile sewer main in the alley is not <br /> available for this project to convey stormwater, thus a new 12" line is shown extended from the <br /> south the serve the project. The city has indicated that the existing 12" clay tile sewer in the <br /> alley is available for the sanitary sewer flows from the building. The plans show a new 8" side <br /> sewer and shallow manhole for the sanitary sewer flows. The plans show a new 10" storm <br /> 1 connection with a manhole to the new extended storm line. <br /> DCI Engineers preformed a qualitative study of the downstream infrastructure by opening <br /> manholes in McDougall Ave and by using the City of Everett GIS utility mapping application. <br /> The following discussion describes the downstream drainage path that the projects stormwater <br /> will travel. <br /> Runoff from the site will be collected in roof drains and routed to the detention pipe located in <br /> the projects garage. The modeling shows that the stormwater system does not enter overflow <br /> ' mode through the entire model run. Upon exiting the site, stormwater will flow in a new 12" <br /> PVC pipe approximately 150' south where it connects to an existing manhole (SMH2995M24) <br /> with 12" PVC pipes that were installed in 2003. From SMH2995M24 a 12"PVC pipe flows east <br /> ' approximately 175 to SMH2995L02 located Mcdougall Ave. The manholes in Mcdougall Ave <br /> were opened in early 2017 and we note that they were recently improved with a fiberglass lining. <br /> Stormwater flows north in Mcdougall approximately 500' to 33th Street where it turns east at <br /> SMH2995F02 and the line size increases to 18"PVC (installed in 2002). Stormwater flows east <br /> in the 18" PVC line approximately 550' where the line size increases to 36" at SMH2995F06 in <br /> Smith Ave. Stormwater then flows approximately 1,500' to 36`h Street and SMH2995P22. At <br /> SMH2995P22 the stormwater flows east in a 54" PE pipe approximately 1,500' to a pumping <br /> station. The pumping station provides pressurized flow to the Water Pollution Control Facility. <br /> ' There is a CSO (SR08)to Snohomish River immediately east of the pump station. This <br /> concludes the qualitative downstream analysis. <br /> I <br /> I <br /> I <br /> Hopeworks II DCI Engineers 7 <br /> Storm Drainage Report <br />