Site Improvement Plans

1.4.2 Site Improvement Plans

Site improvement plans shall portray design concepts in a clear and concise manner. The plans shall present all information necessary for persons trained in engineering to review the plans, as well as those persons skilled in construction work to build the project according to the design intent. Supporting documentation for the site improvement plans must also be presented in an orderly and concise format that can be systematically reviewed and understood by others.

The site improvement plans consist of all the plans, profiles, details, notes, and specifications necessary to construct road, drainage, grading, site infrastructure and development, utilities, off-street parking improvements and offsite traffic, stormwater or other offsite mitigation. Site improvement plans include the following, as described below:

Base map;
Basic site plan requirements; and
Site plans and profiles.

1.4.2.1 Base Map

A base map provides a common base and reference in the development and design of any project. This component of the site improvement plans helps ensure that the engineering plans, grading plans, and erosion and sediment control (ESC) plans are developed from the same background information. All site improvement plans with multiple sheets must provide the following items on every plan sheet:

North arrow.
Graphic scale.
Title block.
Revision block.
Property boundaries.
All easements to remain.
Existing utilities to remain, and all associated easements.
Existing structures (buildings, parking lots and driveways, etc.) to remain.
Existing natural features such as wetlands, streams, slopes and their associated buffers and applicable construction setbacks.

1.4.2.2 Basic Site Plan Requirements

The basic site plan set shall be formatted as noted below, and shall include the items listed under base map (1.4.2.1 Base Map) plus the following:

Plan sheets – Required sheet size is 22″ x 34″ unless waived by the director.
Datum – All datum shall be either NGVD29 or NAVD88.
Scale – Preferred horizontal scales are 1″ = 20′, 1″ = 30′, 1″ = 40′ or 1″ = 50′. Minimum scale is 1″ = 100′ (make the scale as large as the plan sheet size can reasonably accommodate). Profiles shall use 1″ = 5′ or 1″ = 10′ vertical.
Owner, applicant, and agent information – Name, address, email address, and telephone number.
Engineer or person preparing the plans – Name, address, email address, and telephone number of the person preparing the plan (Engineer, if an engineered plan).
Assessor’s tax parcel
Vicinity map – Must be of sufficient clarity to locate the property.
Symbol legend
All existing and proposed:
- Property boundaries with dimensions.
- Structures and other impervious surfaces such as parking lots, driveways, patios, buildings, etc.
- Roads and right of way including roadway and right of way widths, surfacing and road names.
- Sanitary sewers and water utilities.
- Common open space.
- Public dedications.
- Other manmade features affecting existing topography or proposed improvements.
- Easements and tracts.
Offsite waste treatment systems – Show the location of onsite and adjacent offsite waste treatment systems, such as septic tanks and distribution systems, and onsite and adjacent offsite wells and underground storage tanks, all in accordance with Kitsap Public Health District regulations.
Existing topography for the project site – At a minimum, topography shall be included for the limits of all land-disturbed area, flow-contributing area and the downstream flow path. Additional topography may be required to address relevant topographic features. Topographic contour lines must be shown as described in the plan type being prepared.
Land disturbing activity – Show proposed limits of land-disturbing activity.
Surface water discharge – Provide ground surface elevations for a reasonable "fan" around points of discharge extending at least 50 feet downstream of all point discharge outlets.
Flow direction – Provide arrows that indicate the direction of surface flow on all public and private property and for all existing conveyance systems.
Hydrologic features – Provide spot elevations in addition to contour lines to aid in delineating the boundaries and depth of all existing floodplains, wetlands, channels, swales, streams, storm drainage systems, roads (low spots), bogs, depressions, springs, seeps, swales, ditches, pipes, groundwater, and seasonal standing water.
Revisions – Clearly identify on each sheet, by clouding or other visible notation, all revisions made.

1.4.2.3 Site Plans and Profiles

Site plan and profile requirements, in addition to the base map and basic site plan requirements, are detailed below for each type of drainage review.

Simplified Drainage Review

The Simplified Drainage Review shall contain the base map and basic site plan requirements, plus the following:

Existing structures, identifying existing structures to be demolished and existing structures to remain.
Proposed structures and distances from lot lines.
Setbacks and intended use of each (i.e., side yard setback, top of slope setback, etc.).
Clearing limits to show proposed clearing of trees and other vegetation
Locations, types, and sizes of conveyance facilities.
Locations, types, and sizes of on-site stormwater management BMPs.
Locations, types, and sizes of erosion and sedimentation control measures.
Proposed driveways and access points from parcel to main road.
Adjacent property building(s) for shoreline properties.
Location of any critical areas and their associated buffer and/or setback requirements.
Notes indicating compliance with conditions of approval for any associated plat, short plat, large lot subdivision, or Performance Based Development, if applicable.

Simplified Drainage Review – Engineered

All plan sets submitted for Simplified Drainage Review – Engineered shall be prepared by and bear the stamp of a professional engineer, licensed in the State of Washington. The Simplified Drainage Review – Engineered shall contain the base map, plus the following:

Plans drawn on 11″ x 17″ or larger, to scale, with north arrow, adjacent roadways and property dimensions.
Finished grades showing the extent of cuts and fills by existing and proposed contours and profiles.
Notation of the quantities of cut and fill, in cubic yards, throughout the project site.
Topographic contour lines with 2‑foot resolution, drawn from the best available source. Note the source used (LIDAR acceptable).
Project datum if connecting to a County drainage system or local benchmark otherwise.
Plan view of proposed conveyance facilities, including facility sizes, types and materials, lengths of runs and gradients, type of structures, top elevation and invert elevations in/out of structures).
Plan view and cross-section of on-site stormwater management BMPs, flow control BMPs, and water quality treatment BMPs.
Profile of stormwater management facilities if the project is associated with a steep or waterfront slope.
Delineation, labeling, and elevation call-out for the Line of Ordinary High Water (where water feature present) in both plan and profile view.
Roadway cross-sections (including access roads) and proposed ditches and swales.
Critical areas shown (e.g., wetlands, slopes, streams, etc.) with required buffers, setbacks, and any proposed mitigation.

Abbreviated Drainage Review

The Abbreviated Drainage Review shall contain the base map and basic site plan requirements, plus the following:

Contour lines from the best available source, spot elevations, or indications of direction and steepness of slopes, with the source clearly identified.
Areas to be graded, filled, excavated, or otherwise disturbed. The location of graded slopes shall be indicated, together with the proposed steepness and height. The location of any stockpiles, haul roads and disposal sites shall also be indicated.
Grading cross-sections, to scale (minimum of one cross-section in the direction of each slope face).
Locations and types of erosion and sedimentation control measures proposed.
Plan views of conveyance facilities (e.g., pipes, culverts, channels, swales, structures, etc.) showing the following:
1. Conveyance facility locations, sizes, types, materials, lengths of runs, and gradients.
2. Structure identifier (catch basin or manhole number).
3. Type of structure (e.g., Type 2 Catch Basin).
4. Top elevation and invert elevations in/out of structures.
5. Outfalls.
6. Energy dissipators.
7. Notes or references to details, cross-sections, profiles, etc.
Locations, types, and sizes of on-site stormwater management BMPs. Include details for construction as needed.

Abbreviated Drainage Review – Engineered

All plan sets submitted for Abbreviated Drainage Review – Engineered shall be prepared by and bear the stamp of a professional engineer, licensed in the State of Washington. The plan sets shall follow the requirements of site improvement plans and shall contain the base map, basic site plan requirements, plus the following items:

Finished grades.
1. Show the extent of cuts and fills by existing and proposed contours, profiles, and/or other explicit designations.
2. Notation of quantities, in cubic yards, of excavation and/or embankment throughout the project site.
Contour lines at 2‑foot intervals from the best available source, with the source clearly identified. 5‑foot contour intervals may be used in areas of steep slopes. Contours may be limited to the affected portion of the site as described in Item 1.
Project datum.
Plan views of conveyance facilities (e.g., pipes, culverts, channels, swales, structures, etc.) showing the following:
1. Exact locations (e.g., station and offset, or dimensioning) of conveyance facilities.
2. Conveyance facility sizes, types, materials, lengths of runs, and gradients.
3. Structure identifier (catch basin or manhole number).
4. Type of structure (e.g., Type 2 Catch Basin).
5. Top elevation and invert elevations in/out of structures.
6. Outfalls.
7. Energy dissipators.
Notes or references to details, cross-sections, profiles, etc.
Locations, types, and sizes of on-site stormwater management BMPs. Include details for construction as needed.
Cross-sections for at least the following:
1. Roadways, including access roads.
2. Proposed conveyance facilities.
Standard plan notes per Appendix B.

In order to minimize duplication of information where plan and profile views appear on the same sheet, drainage facility information provided in the plan view can be limited to the following: structure identifier, type of structure, pipe types and materials, and lengths of runs.

Additional requirements apply to projects that connect to a drainage system in the right of way, construct improvements in the right of way, or construct improvements in critical areas or critical area buffers, as outlined in the subsequent sections.

Projects that connect to a drainage system in the right of way

If the project will connect to a drainage system in the right of way, include the following items in addition to those provided in Abbreviated Drainage Review – Engineered:

Profile views shall be provided for drainage and roadways, including:
1. Existing and finish grades.
2. Existing underground utilities where such utilities cross proposed drainage facilities.
3. Conveyance facility (e.g., pipes, culverts, channels, swales, structures, etc.) sizes, types and materials, lengths of runs, gradients, structure types and identifying numbers (if multiple structures), invert elevations in/out of structures, and top elevations of structures.
Details of the connection to the drainage system and the energy dissipation structure.
Pavement restoration detail.
Existing drainage system with elevations and inverts for a minimum of 100 feet upstream and downstream of proposed connection.
Proposed means of access to drainage structures.
Conveyance calculations and energy dissipation calculations within the Drainage Report.

Projects that construct improvements in the right of way

If the project is associated with an application to use or improve a county right of way per Chapter 11.36 KCC, the plan submittal shall comply with requirements of Chapter 11.36 KCC and shall include the following items in addition to those provided in Abbreviated Drainage Review – Engineered:

Exact lines, grades, and gradients of proposed roadways.
Profiles of drainage facilities and roadways, including:
1. Existing and finished grades.
2. Existing underground utilities where such utilities cross proposed drainage facilities.
3. Conveyance pipe, culvert, channel, and swale sizes, types and materials, lengths of runs, and gradients.
4. Structures, including types and identifying numbers (if multiple structures), invert elevations in/out of structures, and top elevations.

Projects that construct improvements in critical areas or critical area buffers

If the project is associated with a critical area or critical area buffer, include the following items in addition to those provided in Abbreviated Drainage Review – Engineered:

The critical area being impacted (wetland, slope, stream, etc.) and the proposed mitigation, including details for construction.
Documentation from the professional engineer that the proposed mitigation design is in compliance with critical area codes and standards (may be stated on the face of the plans or in the Drainage Report).
Documentation of concurrence from wetland biologist, geotechnical consultant and/or other professional, as appropriate, that the engineered design meets the recommendation of the professional.
Profile of the drainage system per 1.4.2.3 Site Plans and Profiles if the project is associated with a steep or otherwise geologically hazardous slope, or waterfront slope.
Call-out including label and elevation of the Line of Ordinary High Water, if a waterfront parcel.

Full Drainage Review

All plan sets submitted for Full Drainage Review shall be prepared by and bear the stamp of a professional engineer, licensed in the State of Washington. The plan sets shall follow the requirements of site improvement plans and shall contain the base map and basic site plan requirements, plus the following:

Plan view of the entire project site. In the event that the project site is sufficiently large and detailed drainage plans on any given sheet do not encompass the entire project site, the sheet containing the plan view of the entire site shall serve as an index to subsequent detailed plan sheets.
Project datum.
Locations and elevations of at least two project benchmarks.
Existing topography, including existing structures, for the site and extending 50 feet beyond project boundaries. Existing topography for adjacent rights of way shall be included for the full width of right of way. Slopes 30% or steeper shall be clearly identified.
Contours extending 50 feet beyond project boundaries and including the full width of adjacent rights of way. Contours shall be at 2‑foot vertical elevation intervals, except 5‑foot intervals may be used in areas of steep slopes.
Notation of quantities, in cubic yards, of excavation and/or embankment throughout the project site.
Existing and proposed access locations for the project site.
Project boundaries including bearings and dimensions.
Right of way description including centerline and centerline bearings.
Existing utilities including franchised utilities located above or below ground.
Locations of existing conveyance facilities that transport surface water onto, across, or from the project site. Existing drainage pipes, culverts, channels, and swales shall include invert or flowline elevations.
Location of existing wells and septic components shall be provided on or within 100 feet of project boundaries.
Proposed conveyance facilities, including but not limited to pipes, culverts, channels, swales, structures, outfalls, energy dissipators, etc.
Proposed stormwater BMPs, including but not limited to dispersion, bioretention, permeable pavement, ponds, vaults, etc. Include details for construction as needed.
Locations of all gutter or ditch flowlines, including flow arrows indicating direction of flow. If a cul-de-sac or hammerhead is proposed as part of roadway system, show spot flowline elevations at 25‑foot intervals along the perimeter of the cul-de-sac or hammerhead. Spot elevations at flowlines may also be necessary at intersections.
Plan and profile views of conveyance facilities (e.g., pipes, culverts, channels, swales, structures, outfalls, energy dissipators, etc.) including:
1. Exact facility locations (e.g., station and offset, or dimensioning).
2. Conveyance facility types, sizes, materials, lengths of runs, and gradients.
3. Structure identifier (catch basin or manhole number).
4. Type of structure (e.g., Type 2 CB).
5. Top elevation and invert elevations in/out of structures.
6. Notes or references to details, cross-sections, profiles, etc.
  
  In order to minimize duplication of information where plan and profile views appear on the same sheet, conveyance facility information provided in the plan view can be limited to the following: structure identifier, type of structure, pipe types and materials, and lengths of runs.
Plan and profile views of proposed conveyance facilities in existing and proposed public and private roads. In addition to items 16a through f, profile views shall include:
1. Existing and finished grades.
2. Existing underground utilities where such utilities cross proposed drainage facilities.
Notes or call-outs indicating any proposed phasing of construction.
Standard plan notes per Appendix B.
Details for all proposed drainage structures for which there is insufficient information in the plan view. Details are not required for structures included in the American Public Works Association (APWA)/Washington State Department of Transportation (WSDOT) Standard Plans, provided that the specific APWA/WSDOT Standard Plans are referenced in the construction notes.
Cross-sections for at least the following:
1. Roadways, including access roads.
2. Surveyed cross-sections for new roadways, frontage improvements and/or roadway widening.
3. Proposed on-site stormwater management, flow control, and water quality treatment BMPs.
4. Proposed ditches and swales, including bioretention facilities.