(A)   The owner or developer of property to be developed or changed shall be responsible for all storm drainage flowing from a fully developed watershed. Such responsibility shall include drainage directed to the property by ultimate development, as well as drainage naturally flowing through the property due to topography. When property is proposed for development, use or modification, provisions shall be made for storm drainage in accordance with this chapter.
   (B)   Where the improvement or construction of a storm drainage facility is required along a property line common to two or more owners, the owner proposing development of his or her property shall be responsible for the required improvements at the time of development, including the dedication of all necessary rights-of-way or easements, to accommodate the improvements.
   (C)   When a property owner proposes development or use of only a portion of his or her property, provision for storm drainage in accordance with this chapter shall be required in the portion of the property proposed for immediate development. Improvements of a drainage facility outside such designated portion of the property shall be required for the handling of the development of the designated portion.
   (D)   When a property owner proposes a development, provisions shall be made in the comprehensive drainage plan for control of excess siltation and downstream erosion.
   (E)   The owner shall dedicate the required drainage easements. Determination of the minimum easement required shall be made by the City Engineer.
   (F)   If a property owner or developer desires to modify an existing pond or lake, or impound storm water by constructing a dam within a property for retention or detention, thereby creating a lake, pond, lagoon or basin as a part of the planned development of the property, the standard provisions for storm drainage as established in this chapter shall be applicable, and shall provide that:
      (1)   An engineering plan for such construction, including the comprehensive drainage plan and a storage facility study prepared by a registered professional engineer, shall have been approved by the city;
      (2)   The owner and developer shall retain the constructed lake, pond, lagoon or basin under private ownership, and assume full liability for the protection of the general public from any health or safety hazards related to such construction;
      (3)   The owner and developer shall assume full responsibility for the maintenance of the constructed lake, pond, lagoon or basin;
      (4)   The obligations set forth in this division shall run with the land, and shall be a continuing obligation of the owner of such land; and
      (5)   All Federal, state and county laws pertaining to impoundment of surface water are complied with, including the design, construction and safety of the impounding structure. Any existing structure which is included in a project development area shall be improved to comply with the applicable Federal, state, county and city safety requirements for structures. The design flows shall be based on a fully developed watershed in accordance with the comprehensive land use plan for a 100-year flood. All improvements shall be made to the dam structure at the expense of the developer prior to acceptance of the adjacent street, utilities and drainage improvements.
   (G)   On any existing structure, the owner shall furnish to the city a study by a professional engineer, registered in the state, for approval prior to any proposed alteration. Compensatory storage shall be provided so that a 100-year flood retention capacity is provided.
   (H)   The property owner shall keep the city advised in writing of the current name and address of the responsible agent.
   (I)   All existing water seepage springs or flowing water shall be connected into an underground storm sewer system or shall be discharged into an appropriate facility intended to carry storm water runoff. Such flow shall not be permitted to discharge directly into the street gutter line.
   (J)   Fences (private and public screening) shall be constructed so that an obstruction to surface water flow shall not occur. Such requirement shall include the requirement that erosive conditions shall not be created around, under or near a fence structure.
   (K)   Since urbanization is anticipated on all drainage areas, all improvements shall be designed for the case of full watershed development. The developer shall be responsible for the necessary facilities to provide drainage patterns and controls so that properties within the drainage area, whether upstream or downstream of the development, are not adversely affected by storm drainage from facilities on the development. A letter from an engineer licensed in the state shall be provided certifying that properties within the drainage area will not be adversely affected. The letter shall be sealed, signed and dated.
   (L)   A storage facility study and comprehensive drainage plan shall be provided to the City Engineer with the final engineering drawings. The storage facility study and comprehensive drainage plan shall be prepared in a quantitative manner. The comprehensive drainage plan shall include:
      (1)   Methods to be used for the disposal of storm water runoff from the proposed development;
      (2)   Provisions for contributing drainage from adjacent properties;
      (3)   A topographic drainage area map, indicating all areas contributing drainage runoff;
      (4)   On-site and off-site drainage easements;
      (5)   Proposed and existing storm sewers, curb inlets and open channels;
      (6)   A table showing the drainage subareas, land use, C-factor, rainfall intensity, time of concentration, frequency factor, area in acres and amount of runoff;
      (7)   An indication of runoff at all inlets, dead-end streets and alleys and to adjacent off-site property;
      (8)   An indication of floodplain and flood way boundaries;
      (9)   An indication of siltation and erosion control measures for the entire development and/or stage development;
      (10)   An indication of flow arrows on drawings;
      (11)   A detailed off-site drainage plan.
   (M)   All storm drainage improvements or modifications shall be planned in the best interest of the immediate and adjacent properties, and shall be designed using the design criteria adopted by the City and the most current Federal Emergency Management Agency (FEMA) flood data. The floodplain and floodway boundaries indicated on the drawings shall be determined based on a fully developed watershed, in accordance with the comprehensive land use plan of the City. The FEMA flood boundaries shall represent the minimum flood boundaries to be used.
   (N)   All development shall be designed and constructed in a way to have no negative affect on surrounding areas or unreasonably:
      (1)   Impede the natural flow of surface waters from higher adjacent properties;
      (2)   Alter the natural flow of surface waters so as to discharge them upon adjacent properties at a more rapid rate or in a different location than would result from the pre development natural flow of surface waters; or
      (3)   Collect or concentrate the flow of surface waters for discharge into an existing natural or artificial drainage way in a manner which exceeds the capacity of the receiving water course.
   (O)   Storm drainage released from the site will be discharged to a watercourse of an adequate size to control the peak runoff expected after development. The City Engineer shall be provided the necessary data showing the adequacy of the watercourse. Criteria for on-site development shall apply to off-site improvements. Any discharge point exiting the property shall be within the required drainage easements or right of way on adjacent property. Determination of the minimum easement required shall be made by the City Engineer.
   (P)   The design, size, type and location of all storm drainage facilities shall be subject to the approval of the City Engineer. The requirements set forth in this section shall be considered minimum requirements. The developer and his or her engineer shall bear the total responsibility for the adequacy of the design. The approval of the facilities by the City shall in no way relieve the developer of such responsibility.
   (Q)   Requests for a variance, detailing specific reasons for the variance, shall be submitted in writing. The City Engineer shall make a recommendation to the City Council for its approval of the variance. Variations and modifications to the storm drainage requirement of the city may be made when special or peculiar factors and conditions warrant such variations and modifications, and when such variations and modifications do not affect the general intent, application or spirit of the storm drainage rules and regulations of the city.
(Ord. 09-0721, passed 7-21-2009; Ord. 19-1022B, passed 10-22-2019)  Penalty, see § 155.999