(1) 
Stormwater Plan submittals shall show any surface waters entering the property, flows within the site, and surface waters exiting from the property.
(2) 
Other general requirements of a Stormwater Plan are:
(a) 
Plans for storm drainage and detention facilities shall bear the stamp and seal of a registered Civil Engineer currently licensed by the State of Washington, and qualified by experience and education in the field of hydraulics, hydrology, or a closely related field.
(b) 
All drainage system elements must provide for adequate maintenance and accessibility, and meet standard safety requirements. Storm drainage facilities shall be designed to eliminate interference from underground utilities, and for conditions which exceed design loads for any pipe or other structural element.
(c) 
System reliability should be considered in terms of layout, materials, installation, and maintenance.
(d) 
The impact of a system failure should be analyzed both in terms of on-site and off-site effects. The impacts may affect adjacent or downstream properties, elements of a public storm drainage system, or private systems.
(e) 
No drainage including plumbing originating from the inside of a building or structure shall be connected to the storm drainage or surface water systems.
(f) 
Drainage systems shall be designed to meet applicable State and Federal requirements for water quality prior to discharge to any water body. The Applicant shall be responsible for obtaining any pertinent local, State, and Federal discharge approvals and permits.
(g) 
An Abbreviated Storm Drainage Plan may be submitted for projects which are designated as single family residence; and exceed 5,000 square feet of impervious surfaces for lot sizes less than 0.77 acre, or the percentage of impervious surfaces to lot size is greater than fifteen percent for lot sizes larger than or equal to 0.77 acre. This Abbreviated Plan need not be stamped with the seal of a licensed Professional Engineer.
(Ord. 1161 § 5, 1998)
The latest edition of DOE's Stormwater Management Manual shall be used as a guideline for determining the adequacy of submitted drainage plans. Other manuals and technical references may be used upon the discretion of the Project Engineer and subject to approval by the Administrator.
(Ord. 1161 § 5, 1998)
The Application shall include the following:
(1) 
Vicinity map;
(2) 
Site plan;
(3) 
Storm drainage plan;
(4) 
Hydrological engineering report;
(5) 
Operation and maintenance manual performance bond or security (prior to final approval); and
(6) 
Any supplemental requirements/ conditions by the Administrator or the Department of Community Development.
(Ord. 1161 § 5, 1998)
(1) 
Vicinity Map. The vicinity map shall include the following information.
(a) 
Location of proposed development activities in relation to the local drainage basins.
(b) 
Location of all water courses and other natural surface water system elements downstream and upstream from the proposed development activities.
(c) 
Identification of upstream and downstream drainage areas.
(2) 
Site Plan. The following information shall be included in the site plan for the proposed storm drainage activities.
(a) 
Location and description of all watercourses, impoundments, wetlands, and other surface water features on or adjacent to the site into which surface waters flow.
(b) 
Topography of the site under existing and proposed conditions, in two-foot contours or of sufficient interval to show the general topography of the two conditions.
(c) 
Delineation of floodway and floodplain for a 100-year event, if applicable.
(d) 
Proposed improvements which includes location and description of existing and proposed buildings/structures, impervious surfaces, and storm drainage facilities.
(e) 
Location and identification of all existing and proposed easements for the storm water management systems, and easements to provide adequate access for inspection and maintenance, depicted in relation to existing right-of-way and property lines.
(3) 
Storm Drainage Plan. The Applicant is responsible for submitting a Storm Drainage Plan which meets the design requirements of this Chapter. The Plan shall also include delineation and description of all interim storm water management facilities, including erosion and sedimentation control, to be used during construction. All site development activities shall be conducted in accordance with the Plan.
(4) 
Operation and Maintenance Manual. The Applicant is responsible for submitting an Operation and Maintenance Manual describing required type and frequency of long-term maintenance of drainage facilities, and identification of responsible maintenance organization. This information may be included in the Storm Drainage Plan.
(5) 
Hydrological Engineering Report. A hydrological engineering report shall be submitted and it shall bear the stamp and seal of a registered Civil Engineer currently licensed by the State of Washington, and qualified by experience and education in the field of hydraulics, hydrology, or a closely related field. The submitted information shall follow the requirements in this section and in Article VI.
(6) 
Performance Bond or Other Security. The Administrator may require from the Applicant a licensed surety, cash bond, irrevocable letter of credit from a financial institution, or other like security acceptable to the County, prior to the issuance of Storm Drainage Approval. Such securities shall be administered in accordance with the provisions stated in Article X.
(7) 
Supplemental Requirements/ Conditions Imposed by the Administrator or the Department of Community Development.
(a) 
Supplemental requirements such as studies, inspections, and/or testing at any stage of the application or project to determine measures needed to correct or prevent surface water deficiency occurrences may be imposed.
(b) 
Additional requirements may be deemed necessary to prevent the storm drainage activities from being conducted in a manner hazardous to life or property, or in a manner likely to create a nuisance.
(c) 
All conditions must be identified in the Storm Drainage Plan submitted for approval.
(Ord. 1161 § 5, 1998)
(1) 
An Abbreviated Storm Drainage Plan may be submitted for projects which are designated as single family residence; and exceed 5,000 square feet of impervious surfaces for lot sizes less than 0.77 acre, or the percentage of impervious surfaces to lot size is greater than fifteen percent for lot sizes larger than or equal to 0.77 acre. An Abbreviated Drainage Plan for individual lots may be utilized when a prior approved subdivision cannot reasonably accommodate the drainage from all lots within the overall drainage plan.
(2) 
This Abbreviated Plan need not be stamped with the seal of a licensed Professional Engineer.
(3) 
The Administrator will attach conditions on the project as necessary to control erosion and runoff which shall include but not be limited to:
(a) 
An evaluation of the need for dispersion trenches (french drains, drywells) or other onsite facilities for disposal of runoff from roofs and other impervious surfaces.
(b) 
Routing for storm drainage as necessary and appropriate for the size of the project.
(c) 
Erosion and sediment control BMP's.
(d) 
Streambank erosion control BMP's.
(e) 
Wetland quality control BMP's.
(4) 
An Abbreviated Plan shall contain the following information:
(a) 
Name, address, and telephone of the Applicant.
(b) 
Name, address, and telephone of the person preparing the plot plan.
(c) 
Parcel number(s).
(d) 
Scale and north arrow.
(e) 
Legend if symbols are used.
(f) 
Vicinity map of sufficient clarity to locate the property and the receiving water body.
(g) 
Property boundaries, dimensions, and area.
(h) 
Contour lines from the best available source and specify datum used.
(i) 
Adjoining street names.
(j) 
Existing and proposed structures and other impervious surfaces.
(k) 
Location of waste treatment system.
(l) 
Utility and other easements.
(m) 
Natural drainage channels, wetlands, canyons, gullies, water bodies, etc.
(n) 
Established buffers, significant trees, and natural vegetation easements.
(o) 
Clearing limits.
(p) 
Areas to be graded, filled, excavated, or disturbed.
(q) 
Location of known wells, underground storage tanks, and septic tanks.
(r) 
Location and type of erosion and sediment control measures.
(5) 
Straight lines shall be drawn with a straight edge, and features shall be to scale. Drawing shall be sufficiently clear to see footprint of structures and other aforementioned features.
(Ord. 1161 § 5, 1998)