1) Where not otherwise specified, use the ODOT hydraulics manual specifications.

2) The design of storm drainage systems shall include provisions to adequately control runoff from the entire are of development, including all public and private streets, parking areas, roofs, footings, and area drains of residential, multifamily, commercial and industrial developments, and to provide for the future extension of the storm drainage system to serve the entire drainage basin.

3) All storm water runoff shall be conveyed to an approved point of disposal. In the case of private development, the developer shall pay all costs associated with designing and constructing the facilities necessary to meet this requirement.

4) The design storm peak discharge from the subject property may not be increased from conditions existing prior to the proposed development except where it can be satisfactorily demonstrated by the applicant that there is no adverse impact to downstream properties.

5) Public storm drains within easements will be permitted only upon a showing that drainage cannot be provided from within a right-of-way. Minimum easement widths shall be as outlined herein.

6) All public storm drains shall be designed to flow by gravity to an existing or new storm drain system without lift stations, where determined possible.

7) Except for pollution control or water quality structures, all storm drain system components shall be designed to be self-cleaning to the extent determined by the City Engineer.

1) Surface or subsurface drainage, caused or affected by changing of the natural grade of the existing ground or removal of natural ground cover of placement of impervious surfaces, shall not be allowed to flow over adjacent public or private property in a volume or location materially different from that which existed before development occurred, and shall be collected and conveyed in an approved manner to an approved point of disposal.

2) The approved point of disposal for all stormwater shall be a storm drain, existing well defined open channel, or creek as approved by the City Engineer. Acceptance of proposed point of disposal will depend upon the prevailing site conditions, condition and capacity of existing downstream facilities, and feasibility of alternate design.

3) When private property must be crossed in order to reach an approved point of disposal, it shall be the developer's responsibility to acquire a recorded drainage easement from the private property owner meeting the approval of the City Engineer. The drainage facility installed must be a closed conduit system. Temporary drainage ditch facilities must be engineered to contain the stormwater without causing erosion or other adverse effects to the private property.

1) All development shall tie stormwater analysis to current stormwater masterplan, at minimum shall design consistent with the current stormwater master plan.

2) All developments will be required to provide public storm drainage systems to serve the entire drainage basin including offsite and onsite drainage areas in order to provide for the orderly development of the drainage area, as well as connection (to the new system) of existing storm lines or laterals crossed or intercepted by the new storm lines (including manholes or catch basins which can be served by the new storm lines), at locations as required by the City Engineer (see also PWDS 1.6.e). This shall include the extension of storm drain lines in easements across the property to adjoining properties and across street frontages of the property to adjoining properties when the storm drain system is located in the street right-of-way. This shall include extension to the far side of streets fronting or adjacent to the development as required to avoid work within or under these streets in the future. This shall include storm drains which are oversized to provide capacity for upstream development.

1) The following factors as a minimum shall be addressed in the design of storm drainage systems and determination of design flows.