A. Stormwater Management Plan Required: Any activity regulated by this chapter shall require the development of a comprehensive stormwater management plan meeting the requirements of sections 13.30.050 and 13.30.060 of this chapter. Stormwater management plans shall be approved by a qualified, licensed professional and submitted to the city for review.
1. Exceptions:
a. Stormwater management plans for new single-family residential structures or additions to single-family residential structures are not required to be designed by a qualified, licensed professional unless required by the city under subsection A1b of this section.
b. The administrator may require that the stormwater management plan be signed by a registered civil engineer if he or she determines that off site drainage or adjacent property rights are affected by the plan.
B. General Plan Requirements: Each stormwater management plan must contain the following general elements:
1. The necessary maintenance system, including an acceptable plan for sustained functioning of the collection and treatment system. Unless the plan identifies another responsible party, the parties identified in section 13.30.100 of this chapter shall be responsible for maintenance of all elements of the stormwater collection and treatment system. Maintenance activities shall include (but not be limited to), watering, mowing and fertilizing of infiltration basins, sod renovation of infiltration basins (unless otherwise provided in this chapter), sediment and debris removal from detention basins, debris removal and cleaning of all inlets, piping, outlet structures, slope protection, etc.
2. The easements necessary to provide continued maintenance of the system.
3. Clearly identified stormwater facilities including, but not limited to, pipes, inlets, catch basins, infiltration basins, basins, and swales.
C. Required Stormwater Plan Elements: In addition to the general plan requirements required by subsection B of this section, stormwater management plans must contain the following parts:
1. Design Calculations: The plan shall present all pertinent calculations necessary to determine the required size of elements of the system. These elements include, but are not limited to, off site drainage onto the property, pre and post development runoff, infiltration basins, detention and/or retention facilities, pipes, swales, culverts, ditches, and catch basins.
2. Site Plan: The site plan shall include the following:
a. Property boundaries and all existing natural and manmade features and facilities within fifty feet (50') of the site, including streets, utilities, easements, topography, structures, and drainage channels.
b. Final contours.
c. Location of all proposed improvements, including paving, structures, utilities, landscaped areas, flat work, and stormwater control facilities.
d. Proposed drainage patterns including ridgelines and tributary drainage areas.
e. Stormwater control facilities, including invert elevations, slopes, length, cross sections, and sizes. Construction details shall be shown for infiltration basins, and/or detention/retention/construction waste facilities.
f. Existing and proposed drainage/stormwater easements.
g. Location of all BMPs, temporary and permanent.
h. Final vegetation, landscape, and permanent stabilization measures.
3. Erosion, Sediment And Construction Site Waste Control Standards: The design, testing, installation, and maintenance of erosion, sediment and construction site waste controls shall be in accordance with city approved best management practices (BMPs). An erosion, sediment and construction waste control plan shall be submitted and approved prior to initiation of any site clearing, excavation, and grading or other development activity. Both temporary and permanent erosion, sediment and construction waste control measures shall be included. The plan shall represent the minimum requirements for the site. Additional measures may be required by the city in the event of unexpected storm occurrences, repair or maintenance of existing systems, or replacement of nonfunctioning systems.
a. The permit holder and owner of the property are responsible for maintenance and upkeep of both temporary and permanent erosion, sediment and construction waste control measures unless the erosion, sediment and construction waste control plan identifies another person or entity as the responsible party. (Ord. 3455, 2012)