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<br />i <br /> <br />~" <br />I <br /> <br />.'i;;;. <br /> <br /> <br />I <br /> <br />~. <br /> <br />I <br /> <br />~--. <br /> <br />J <br /> <br /> <br />~c <br /> <br />(I) <br />.l) <br /> <br />B. Design storm runoff, based on the type of facility and storm frequency listed in Section <br />5.4. <br />C. 100 - year runoff <br />D. Route of overland flow including the overflow to a drainage channel or detention facility <br />E. Water surface profiles for the 25-year and/or I DO-year storms in the outfall channel. All <br />available information will be considered when making this determination. <br />F. Flow per inlet <br />G. Ma."Ximum ponding elevation <br /> <br />5.2.2 <br /> <br />Detailed drainage calculations shall be submitted with the construction plans. <br /> <br />f, <br /> <br />5.2.3 A lot grading plan should demonstrate that the finished grading plan will drain to approved <br />collection and discharge points and thafthe overland flow of water from adjacent properties will <br />not be impacted <br /> <br />'t <br />-*.- <br />r <br /> <br />,. <br /> <br />5.2.4 The hydraulic gradient for the design storm may be shown on the construction drawings. <br />Calculations for the elevat.i.qn.fu.r the hY....dI].yli.g...gr%.GimLshall_!?~Jlrovide~ wit~~~torm <br />drain3l?e calcu1atio~. ~- hydraulic gradient must be b~iow-~~__~~~~_f.9~ -0-~ de~ st~ <br />The tailwater elevauo;;soased on a 25-year rrequency ill the outfall channel shill oe usea-for] <br />calculations of the hydraulic gradient. <br /> <br />I <br /> <br />;:.1; <br /> <br />f <br /> <br />L. <br /> <br />5.3 USE OF PREVIOUSLY DESIGNED AND IN'STALLED rnFRASTRUCTURE <br /> <br />(Situations where previously installed infrastructure is in place but not yet utilized to its deSign) <br />capacity will be considered on a case by case basis. The developers engineer shall after <br />consultation with the City, prepare a report that: <br /> <br />a. outline the original design criteria <br />b. evaluates the impact of the original design on the receiving stream, adjoining <br />properties and/or the 100 year Floodplain. <br /> <br />r <br /> <br />Based on the report, the City Engineer may allow full or partial use 'of the previously installed <br />infrastructure and may require it to be supplemented with detention or other facilities. <br /> <br />5.4 STORM FREQUENCY, RUNOFF .AND DATUM <br /> <br />A Storm Frequency <br /> <br />All drainage improvements shall be designed for the following storm frequencies. <br />---:~ <br /> <br />Type of Facility <br />R()a~ Side Ditches and Culverts .//' <br />StomfSewers ~/ <br />Ditches & Culverts Drainage 100 es and more <br />Bridges / <br />Creeks // <br />// <br />Detention FacilitieS <br /> <br />3 year <br />3 year <br />25 year <br />100 year <br />100 year <br />Refer to Section 5.5 <br /> <br />~nl fr <br /> <br />B.---Stoml-R~ff"~ -- <br /> <br />Design flow of storm water runoff is to be calculated using the Rational Method. <br /> <br />The Rational Method is based on the direct relationship between rainfall and runoff, and <br />the method is expressed by the following equation: <br /> <br />Stormwater Criteria Page 2 of 10 <br />