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3.0 OFFSITE ANALYSIS <br />Qualitative Analysis <br />A qualitative downstream analysis was performed for the project site. Due to the <br />development surrounding the subject property there is no upstream basin which <br />discharges stormwater runoff to the project site. All available information regarding <br />existing and potential water quality, runoff volumes and rates, flooding and stream bank <br />erosion problems within the study area have been reviewed. Reviewed material included <br />NRSC soil information, City of Everett maps and assessment reports prepared for other <br />projects in the area. See Appendix A for appropriate maps and information. <br />With the proposed development, stormwater will be collected on -site and conveyed East <br />through a 12" pipe to a pond about 100 feet east of the property. Overflow from the <br />pond is conveyed south through 18" and 24" pipes to a drainage ditch. <br />The upstream downstream flow path was followed and observed for 1/4 mile using <br />Snohomish County GIS. Pipe information is displayed in order from upstream to <br />downstream: <br />1) <br />50 <br />feet of 12" <br />0 corrugated metal pipe <br />@ 0.40% <br />2) <br />87 <br />feet of 12" <br />0 corrugated metal pipe <br />@ 1.78% <br />3) <br />134 <br />feet of 12" <br />0 corrugated metal pipe <br />@ 0.12% <br />4) <br />145 <br />feet of 18" <br />0 corrugated metal pipe <br />@ 0.81% <br />5) <br />200 <br />feet of 24" <br />0 corrugated metal pipe <br />@ 0.57% <br />6) <br />70 <br />feet of 24" <br />0 corrugated metal pipe <br />@ 0.96% <br />The five pipe runs mentioned above total a flow path of approximately 679 feet. There <br />were no apparent signs of capacity issues or flooding issues identified in this <br />downstream system. See Appendix A for the downstream map. <br />