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<br />5.0 Conveyance Requirements <br /> <br />Conveyance structures (outfalls, pipes, swales ditches, culverts, etc.) shall be designed in <br />accordance to the Mooresville Stormwater Design Manual to fulfill the following <br />requirements: <br /> <br />5.1 Outfalls - All proposed pipe outfalls shall have an adequate receiving facility <br />identified on the plans. There shall be no increase in erosion and <br />sedimentation on adjoining properties. <br /> <br />5.2 Pipe Systems - All pipe systems shall accommodate the lO-year storm event <br />with the hydraulic gradeline in the crown of the pipe. In addition, an overflow <br />route to the detention structure shall be provided for the flows resulting from <br />storms with a return period greater than the lO-year. In situations where an <br />overflow route to the detention structure cannot be created, the pipes shall be <br />designed with the lOO-year hydraulic gradeline runoff below the top of casting <br />or provide an easement encompassing the lOO-year inundated areas. <br /> <br />5.3 Inlets - Inlets shall be located to limit gutter spread during the lO-year storm <br />event such that one lane, based on the roadway width, is open. Multi-lane <br />roadways shall maintain one clear driving lane in both directions. Inlets shall <br />have the capacity to accommodate the lO-year storm or the lOO-year storm <br />where overflow channels are not provided. <br /> <br />5.4 Culverts - Culverts under roadways designated as thoroughfares, arterials or <br />that provides the only means of ingress and egress to developments, shall <br />accommodate the lOO-year flow to the culvert without overtopping the <br />roadway. <br /> <br />Culverts under collector roadways (those roadways connected to designated <br />thoroughfares and arterials) shall accommodate the 50-year flow to the culvert <br />without overtopping the roadway. <br /> <br />All other roadway culverts shall accommodate the 25-year flow to the culvert <br />without overtopping the roadway. <br /> <br />Driveway culverts shall accommodate the lO-year flow to the culvert without <br />overtopping the driveway. <br /> <br />5.5 Lift Stations - Lift stations shall not be designed as part of a stormwater <br />conveyance system. Proposed stormwater lift stations will only be reviewed if <br />complete documentation of no other reasonable option is provided. <br />Stormwater lift stations will be approved on a case-by-case basis. <br /> <br />5.6 Swales - Swales shall be designed to accommodate the lO-year storm runoff <br />within the proposed banks. <br /> <br />MOORESVILLE STORMW ATER MANAGEMENT ORDINANCE <br />18 <br />