To provide for the drainage of surface water from all residential, commercial and industrial development; to minimize erosion; to reduce degradation of water quality due to sediments and pollutants in storm water runoff. (Ord. 619, 2003)

A. The provisions of this chapter shall apply to all new residential land partitions and subdivisions, planned unit developments, multi-family developments, commercial developments, and industrial development; and to the reconstruction or expansion of such developments.

B. The provisions of this chapter shall apply to all drainage facilities that impact any public storm drain system, public right-of-way or easement dedicated to or located within all off-street parking and loading areas.

C. All storm water runoff shall be conveyed to a public storm sewer or natural drainage channel having adequate capacity to carry the flow without overflowing or otherwise causing damage to public and/or private property. In the case of private development, the developer shall pay all costs associated with designing and constructing the facilities necessary to meet this requirement. (Ord. 619, 2003)

No construction of any facilities in a development included in Section 17.72.020 shall be permitted until a storm drainage and erosion control plan for the project is prepared by an engineer registered in the state of Oregon and approved by the city. This plan shall contain at a minimum:

A. The methods to be used to minimize the amount of runoff, siltation, and pollution created from the development both during and after construction.

B. Plans for the construction of storm sewers, open drainage channels, and other facilities that depict line sizes, profiles, construction specifications, and other such information as is necessary for the city to review the adequacy of the storm drainage plans.

C. Design calculations shall be submitted for all drainage facilities. These drainage calculations shall be included on the site plan drawings and shall be stamped by a licensed professional engineer in the state of Oregon. Peak design discharges shall be computed using the rational formula and based upon the design criteria outlined in the Standard Specifications for Public Works Construction in the City of Carlton and the most current adopted storm drainage master plan. (Ord. 619, 2003)

A. All development shall be planned, designed, constructed and maintained to:

1. Protect and preserve existing natural drainage channels to the maximum practicable extent;

2. Protect development from flood hazards;

3. Provide a system by which water within the development will be controlled without causing damage or harm to the natural environment, or to property or persons within the drainage basin;

4. Assure that waters drained from the development are substantially free of pollutants, through such construction and drainage techniques as sedimentation ponds, reseeding, phasing or grading;

5. Assure that waters are drained from the development in such a manner that will not cause erosion to any greater extent than would occur in the absence of development;

6. Provide dry wells; french drains, or similar methods, as necessary to supplement storm drainage systems;

7. Avoid placement of surface detention or retention facilities in road rights-of-way.

B. Where culverts cannot provide sufficient capacity without significant environmental degradation, the city may require the watercourse to be bridged or spanned.

C. In the event a development or any part thereof is traversed by any watercourse, channel, stream or creek, gulch, or other natural drainage channel, adequate easements for storm drainage purposes shall be provided to the city. This does not imply maintenance by the city.

D. Channel obstructions are not allowed except as approved for the creation of detention or retention facilities approved under the provisions of this title. Fences with swing gates may be utilized.

E. Prior to acceptance of a storm sewer system by the city, the storm sewers shall be flushed and inspected by the city. All costs shall be borne by the developer.

F. Easements for creeks and other watercourses shall be provided and shall extend fifteen (15) feet in each direction from the waterway centerline, ten (10) feet from the top of a recognizable bank, or sufficient width to pass ten (10)-year flood flows or one hundred (100)-year floodway on FEMA regulated stream, whichever is greater. The easements required by this chapter shall be held to prohibit the placement of any building on or over the easement, but shall not preclude landscaping, and shall be held to require restoration of the site following any excavation or other disturbance permitted by the easement. (Ord. 619, 2003)