The purpose of this chapter is to establish regulations to minimize impacts of hillside development and protect views in hillside areas. The intent of these regulations is to ensure that the design of new development complements existing topography so that improvements result in a natural and unobtrusive appearance. These regulations are also established to minimize risk of personal injury, impacts to water quality, and damage to property from landslides, erosion, earth creep, stormwater runoff, and other hazards in and near hillside areas of the city. [Ord. 12-4. DC 2012 § 122-769].

A. The provisions of this chapter apply to any subdivision, new use, or structure (including accessory structures), additions to existing structures that exceed 50 percent of the size of the existing structure, and other development on any parcel with an average slope of 15 percent or greater, hereinafter referred to as “hillside parcels.”

B. Slope is measured by taking the vertical distance, or “rise,” over the horizontal distance, or “run.” The resulting fraction, or percentage, is the “slope” of the land.

C. In the event of a conflict between the provisions of this chapter and other development code regulations, including the provisions of the applicable zoning district, the provisions of this chapter shall apply.

D. The provisions of this chapter do not apply to additions to existing single-family residences when the area of the addition is less than 50 percent of the area of the existing residence and there is no hillside development permit for the existing residence. [Ord. 12-4. DC 2012 § 122-770].

A. Maximum Allowed Density.

1. The maximum residential density for any hillside parcel shall be calculated according to the following figure:

FIGURE 18.300.030 – MAXIMUM ALLOWED DENSITY

2. The maximum intensity or floor area ratio (FAR) for nonresidential development shall be reduced for hillside parcels in compliance with Table 18.300.030.

3. The maximum allowed density or intensity in subsections (A)(1) and (2) of this section may be required to be further reduced by the review authority, if necessary to:

a. Protect the health, safety, or general welfare of persons residing or employed in the vicinity of the site, protect property and improvements in the vicinity, or to protect the general welfare of the city;

b. Protect water quality in downstream creeks or rivers; or

c. Preserve significant views from public open spaces, rights-of-way, or other public places.

4. An exemption from the maximum allowed density or intensity may be approved by the review authority on any hillside parcel meeting all of the following conditions:

a. The average slope is less than 20 percent;

b. The parcel has previously been developed, or the parcel is abutted on all four sides with developed properties, and the proposed density or intensity is consistent with the adjacent development;

c. Open space does not exist on any side of the parcel; and

d. The parcel is less than five acres in size.

5. Any hillside parcel exempted from the maximum allowed density or intensity by subsection (A)(4) of this section shall comply with all of the other provisions in this chapter.

B. Single-Family Residences. Nothing in this chapter shall prohibit the construction and occupancy of a single-family residence on a hillside parcel created pursuant to the Subdivision Map Act and the city’s subdivision ordinance. New development shall be built in compliance with this chapter. [Ord. 12-4. DC 2012 § 122-771].

A hillside development use permit (HDP) shall be required for all development as described in Chapter 18.445 CDC on any hillside parcel. [Amended during 2014 recodification; Ord. 12-4. DC 2012 § 122-772].

All hillside development shall comply with the following development standards in addition to the standards for the applicable zoning district.

A. Slope Limits. Land with an average slope of 30 percent or more shall not be developed. Development on land with an average slope of 20 percent or more shall be limited to a single-family dwelling. Encroachment of building envelopes onto slopes exceeding these percentages may be permitted by the review authority only when all of the following findings can be made:

1. It is substantially infeasible to locate the proposed building inside the maximum percent slope area;

2. Where such location would have a substantially less impact on the environment;

3. Where such location is deemed appropriate to facilitate clustered development; and

4. Measures are included that provide adequate mitigation of environmental impacts such as visual, biological, and geotechnical impacts.

B. Treatment of Sloped Areas.

1. All areas with an existing average slope of 30 percent or greater shall be left undisturbed;

2. All areas with an existing average slope of 20 percent or more that are not covered with structures or used for access to the property shall not be paved, and shall only be disturbed as necessary to develop the site;

3. Slopes created or altered by grading shall not exceed 30 percent; and

4. For slopes up to 15 percent, impervious surfaces shall not exceed 40 percent of the gross land area. Slopes that exceed 15 percent shall not have impervious surfaces that exceed 30 percent or less.

C. Protection of Ridgeline Views. The highest point of any structure shall not be located within 100 vertical feet of a ridgeline (i.e., a ground line located at the highest elevation of a connected series of major and minor hills).

D. Subfloor Parking for Nonresidential Buildings. The maximum allowable floor area for nonresidential development may be increased to a maximum of 20 percent when at least 25 percent of the required parking spaces are provided below grade, or in a subfloor, and incorporated into the design of the building. The 20 percent increase in FAR shall be applied to the total floor area calculated after the maximum allowable FARs in Table 18.300.030 are applied. In no case shall a project exceed the FAR or other development standards of the applicable zoning district.

E. Fences. Exterior fencing on hillside parcels shall be limited to wire mesh with wood posts or other similar natural materials that are transparent and do not significantly affect views of the site. Chain link fencing, solid wood, masonry, or other opaque fence/wall materials are prohibited. [Ord. 12-4. DC 2012 § 122-773].

A. As a part of each application for an HDP, the applicant shall submit a preliminary soils or geotechnical report prepared by a qualified professional, at the applicant’s expense. The study shall include all information and materials required by the city engineer.

B. The report shall be reviewed and approved by the city engineer or by a consulting geotechnical engineer, hired by the city at the applicant’s expense.

C. The applicant shall incorporate all recommendations into the design of the project.

D. This requirement may be waived if the city engineer determines that the project, because of its size, location, or design, will not have a significant impact on the hillside, or that sufficient information already exists and further analysis is not necessary. [Ord. 12-4. DC 2012 § 122-774].

All HDPs shall comply with the following criteria where applicable:

A. Terrain Alteration. Development shall be designed to fit the terrain rather than altering the terrain to fit the development.

1. Final contours and slopes shall be rounded and shaped to simulate the existing topography, and shall blend with adjacent landforms.

2. Development patterns that require excessive cuts or fill, or form visually protruding horizontal bands, or steeply cut slopes for roads or lots shall be avoided. In particular, wide building pads and terraces interspersed with slopes shall not be created, and ridgelines, knolls, and significant tree masses shall be maintained.

B. View Protection. Views from public or private open space areas, rights-of-way, and other public places shall not be significantly affected, and development shall avoid significant intrusion into views from adjoining up-slope properties.

C. Structure Siting and Design. Site design shall utilize varying setbacks, structure heights, split-level foundations, low retaining walls, and terraces to blend structures into the terrain. Front building setbacks shall be varied and staggered consistent with natural hillside character.

D. Location of Structures. Structures shall be located in the most accessible, least visually prominent, and most geologically stable portion of the site. When feasible, structures shall be located so that they will be screened by existing vegetation, rock outcroppings, or depressions in topography. Buildings and improvements shall be located to save trees and minimize grading. Additional native plant materials shall be added to augment the screening qualities of existing vegetation, where appropriate.

E. Retaining Walls.

1. Tall and/or long retaining walls shall be prohibited. Retaining walls shall be limited to four feet in height, unless otherwise approved due to geological or other physical constraint;

2. Retaining walls shall be stepped with landscaped terraces to reduce the individual height of walls;

3. Materials for retaining walls shall be durable and resistant to rot, structural pests, or other environmental factors. Cast in place concrete or concrete block are the preferred materials; and

4. Access to the site and excavation for walls shall be carefully controlled to minimize disturbance to the hillside and slope face.

F. Exterior Lighting. Lighting for hillside development shall be designed to eliminate direct and off-site glare and the spill of light to surrounding areas. Site and building designs shall incorporate low-intensity exterior lighting. Low ground-level fixtures shall be used rather than fewer, taller light fixtures.

G. Colors and Materials. A harmonious mixture of exterior colors and materials shall be used to blend structures and site improvements with the natural hillside as follows:

1. Darker, flat-toned colors, such as browns, black, greens and terra cotta, are preferred and light or bright colors shall be avoided, including white stucco walls and reflective roofing; and

2. As appropriate, a mix of rough-textured materials, such as stucco, wood, brick, and coarse block shall be used.

H. Building Design. To reduce scale and massing, structures and improvements shall:

1. Be scaled to complement the hillsides and to avoid excessively massive forms that dominate views of the hills;

2. Be compatible with the existing adjacent neighborhood in terms of scale;

3. Be designed to locate windows, balconies, and outdoor living areas with consideration for the privacy of adjacent dwellings and yards, to the maximum extent feasible;

4. Be stepped back to follow the natural contour of the slope, with the height of the tallest vertical plane not exceeding 20 feet measured from grade; and stepping back a minimum of 10 feet at the 20-foot limit. See Figure 18.300.030 (Maximum Allowed Density);

5. Use varying vertical planes and overhangs as a means to create changing shadow lines;

6. The roof pitch shall follow the angle of the site’s slope and roof slopes shall be varied to avoid a monotonous appearance; and

7. Structural underpinnings for decks, additions, or foundation structures shall be integrated into the design of the building and shall not be visible from off site.

I. Street and Driveway Layout. Streets and driveways shall follow the natural contours of the terrain to reduce grading, tree removal, and visual impacts, where possible. The following street and driveway designs may be considered subject to approval by the city engineer and planning division:

1. Cul-de-sacs, split roads, loop roads, and parallel street parking where appropriate to fit the natural topography; and

2. Narrower street sections as identified in CMC 17.20.030 (Subdivision design standards) where appropriate.

J. Lot Configuration. The creation of new lots or the adjustment of lot lines shall:

1. Be practical for improvements, due to steepness of terrain, geologic hazards, or location of watercourses or drainage;

2. Be designed to avoid grading or building within 25 vertical feet of the top five-foot contour of a ridgeline or knoll;

3. Be configured to minimize grading and preserve topographic and geologic features;

4. Take into account natural landforms and vegetation to the greatest extent possible;

5. Be designed to provide residential interior side yard fencing at the top of slope in order to provide privacy and to avoid the double fencing at the top and bottom of a slope; and

6. Accommodate drainage with swales and catch basins rather than V-ditches and benches, and avoid lot-to-lot drainage with property lines at the top of slope areas. [Ord. 12-4. DC 2012 § 122-775].

All hillside development permits shall be processed, reviewed, and approved or disapproved in accordance with the provisions in Chapter 18.445 CDC (Hillside Development Use Permit) and all approvals shall be consistent with the findings in CDC 18.300.090. [Ord. 12-4. DC 2012 § 122-776].

The review authority shall approve or conditionally approve a proposed HDP in compliance with Chapter 18.445 CDC upon finding that:

A. The design, scale, massing, height and siting of the project is compatible with the site and consistent with the character and scale of the surrounding developed neighborhood;

B. The design and site layout of the project respects and protects the natural environment to the maximum extent feasible;

C. The site grading is sensitive to the hillside site, minimizes tree removal, and provides safe site access;

D. The project is consistent with the general plan, and meets the development standards of the applicable zoning district and the hillside development and design standards;

E. The project screens development to the extent feasible through clustering and/or avoidance of highly visible hillsides, ridgelines, and knolls; and

F. The project incorporates adequate access, public services, and utilities. [Ord. 12-4. DC 2012 § 122-777].

This chapter provides standards for the protection, maintenance, enhancement, and restoration of creeks, streams, and waterways in a manner that preserves their ecological integrity, function, and value, as follows:

A. Establish adequate buffer areas along waterways to avoid flood hazards and maintain or expand storage capacity for flood waters;

B. Protect water quality and in-stream habitat;

C. Preserve, enhance, and restore riparian habitat, adjacent wetlands, and upland buffers;

D. Provide for continuous wildlife migration corridors that connect habitat areas; and

E. Allow development that is compatible with the important physical, habitat, aesthetic, and recreation functions of waterways, while ensuring that these functions and values are protected in perpetuity. [Ord. 12-4. DC 2012 § 122-799].

The provisions of this chapter apply to any subdivision or proposed development, with the exception of public projects, as follows:

A. On any site adjacent to or crossed by a watercourse that is shown as a creek or stream channel on the city’s general plan map or as a blue line on the most recent United States Geological Survey (USGS) 7.5-minute topographic quadrangle map; or

B. On any site within the floodplain as defined in CMC 15.75.050. [Ord. 12-4. DC 2012 § 122-800].

A design and site development permit shall be required for improvements to any applicable property in addition to any other permit (subdivision, use permit, design review, etc.) required by the development code. All applications for a site development permit shall include:

A. A site-specific hydrologic study prepared by a hydrologist, civil engineer, or other qualified professional, approved by the city, to identify the precise locations of the waterway centerline, the boundary/top of bank of the waterway, and the boundary of the 100-year floodplain. This requirement may be waived if the city engineer determines that the project, because of its size, location, or design, will not have a significant impact on the waterway, or that sufficient information already exists and further analysis is not necessary. This study shall include all information and materials as required by the city engineer; and

B. Grading and improvements plans shall be submitted along with the hydrologic study. [Ord. 12-4. DC 2012 § 122-801].

A. Structure Setbacks for Unimproved Channels.

1. “Unimproved channel” means a watercourse, which has been left as much as possible in its natural state.

2. “Watercourse” means any natural or manmade channel for transporting water, including the stream bed and the banks, whether continuously flowing or intermittent.

3. “Structure setback line” means the line separating the structure setback area from the remainder of the lot. For unimproved earth channels, a structure setback line shall be shown on all plans submitted with any development application as follows: The thalweg of the channel shall be shown as accurately as possible on the plan, and a dashed line shall indicate the appropriate setback with a note describing the method used to determine the top of bank, selected from those set forth herein.

4. “Top of bank” means the point where a line with a slope of two-and-one-half horizontal to one vertical extending from the toe of the channel intersects the existing ground, whichever point is the greatest vertical distance above the channel invert. A separate top of bank shall be determined for each side of the channel. (See Figure 18.305.040.)

Figure 18.305.040

B. The structure setback line for unimproved channels shall be determined by measuring the following horizontal distance away from the top of bank on each side of the watercourse as shown in Table 18.305.040. Where significant riparian vegetation exists beyond these setbacks, additional setbacks may be required by the review authority to preserve the existing vegetation.

C. Trails. Paths or trails may be located within a structure setback; however, no road, parking area, parking space, or paved area shall be constructed within the setback area.

D. Alteration of Natural Features. No grading or filling, planting of exotic/nonnative or nonriparian plant species, or removal of native vegetation shall occur within structure setback area, except where authorized for flood control purposes with the proper permits issued by the California State Department of Fish and Game, and all other applicable state and federal agencies.

E. Design of Drainage Improvements. Where drainage improvements are required, they shall be placed in the least visible locations and designed with natural materials through the use of river rock, earth-tone concrete, and landscaping with native plant materials.

F. Use of Permeable Surfaces. The proposed project should incorporate permeable surfaces (for example, wood plank decks, sand-joined bricks, and stone walkways) where feasible, to minimize off-site flows and facilitate the absorption of water into the ground.

G. Creek Bank Stabilization. Development projects or land use changes that increase impervious surfaces or sedimentation may result in channel erosion. This may require measures to stabilize the banks.

1. Creek rehabilitation is the preferred method of stabilization, with the objective of maintaining the natural character of the creek and riparian area. Rehabilitation may include enlarging the channel at points of obstruction, clearing obstructions at points of constriction, limiting uses in areas of excessive erosion, and/or restoring riparian vegetation.

2. Concrete channels and other mechanical stabilization measures shall not be allowed unless no other alternative exists.

3. If bank stabilization requires measures other than rehabilitation or vegetative methods, hand-placed stone or rock riprap are the preferred methods (as specified in subsection (F) of this section).

H. Physical and Visual Access. The provision of multi-purpose creekside trails and public open space is encouraged. Open space areas should include planting for riparian enhancement with native shrubs and trees. Paths and trails, lighting, benches, exercise courses/stations, and trash receptacles may also be provided, outside of the riparian habitat area, where appropriate. [Ord. 12-4. DC 2012 § 122-802].

A design and site review permit shall be required for all improvements to all applicable properties. The site review permit shall be processed, reviewed, and approved or disapproved in accordance with the provisions in Chapter 18.415 CDC (Design and Site Review) and all approvals shall meet the development standards in CDC 18.305.040. [Amended during 2014 recodification; Ord. 12-4. DC 2012 § 122-803].

A. Property owners with a creek on their property or fronting on a creek shall maintain the creek and abutting vegetation, including removal of any trash accumulated by the creek.

B. Any permit approval shall require the property owner to enter into a city-approved agreement to ensure the improvements are maintained continuously in compliance with the conditions of approval imposed by the review authority, in accordance with Chapter 18.520 CDC (Performance Guarantees and Property Maintenance). [Ord. 12-4. DC 2012 § 122-804].

This chapter provides regulations for the protection, preservation, maintenance, removal, and replacement of trees associated with proposals for construction and development. It is the intent of this chapter to protect large native trees, trees of historic or cultural significance, groves and stands of mature trees, and mature trees in general. This chapter is intended to be used in tandem with other provisions of the Concord Municipal Code (Chapter 8.40 CMC, Trees and Shrubs) which provide for tree protection, maintenance, and preservation on public property and on private property containing protected trees or designated heritage trees. [Ord. 12-4. DC 2012 § 122-825].

The provisions of this chapter shall apply to the removal or relocation of any protected tree in all zoning districts when the removal or relocation is associated with a proposal requiring a planning permit pursuant to the Concord Development Code. This shall include tree removal or relocation on undeveloped property in order to facilitate development, and removal or relocation on developed property to facilitate building construction, expansion, renovation, or other property improvements. The provisions of this chapter shall not apply to the removal of trees which are not associated with a planning or building permit. Such activities are governed by Chapter 8.40 CMC.

A. Protected Trees. A protected tree is:

1. Any of the following listed native trees with a diameter of 12 inches or more as measured 54 inches above the ground (e.g., diameter at breast height) or a multi-stemmed native tree on the list below where the sum of all stem diameters is 12 inches or more as measured 54 inches above the ground: Valley oak (Quercus lobata), Blue oak (Q. douglasii), Coast live oak (Q. agrifolia), California bay (Umbellaria californica), California buckeye (Aesculus californica), and California sycamore (Platanus racemosa).

2. Other trees with a diameter of 24 inches or more as measured 54 inches above the ground (e.g., diameter at breast height) or more or a multi-stemmed nonnative tree where the sum of all stem diameters is 24 inches or more as measured 54 inches above the ground;

3. Any tree which has been previously designated as a heritage tree by planning commission resolution;

4. A tree required to be planted, relocated, or preserved as a condition of approval of a tree permit or other discretionary permit, and/or as environmental mitigation for a discretionary permit; and

5. A tree with a trunk diameter of six inches or more or one component trunk of a multi-stemmed tree with a diameter of four inches or more as measured 54 inches above the ground that is located within the structure setback of creeks or streams as defined in CDC 18.305.040(A) (Structure Setbacks for Unimproved Channels).

B. Exempt Trees or Nonprotected Trees. Includes any member of the genus Eucalyptus, any member of the genus Acacia, any common palm tree (Arecaceae), Monterey pine (pinus radiata), Tree of Heaven (ailanthus altissima) and any member of the genus Ligustrum (commonly referred to as privet), unless such tree has been specifically designated a “heritage tree” by resolution of the planning commission.

C. Tree Protection Zone (TPZ). A tree protection zone shall be established for each protected tree at the outer edge of the tree canopy or drip zone in all directions, unless a larger area is required by an ISA certified arborist (“arborist”).

D. Activities Requiring a Tree Permit. Any activity that is subject to a planning permit as required in Division VII of this title (Permits and Permit Procedures) shall be required to obtain a tree permit prior to:

1. The relocation, removal, cutting-down, or other act that causes the damage or destruction of a protected tree;

2. Any grading, paving, or other ground-disturbing activity within the tree protection zone (TPZ) where the encroachment exceeds 20 percent of the protected zone.

E. Exemptions. The removal or relocation of a protected tree is exempt from the provisions of this chapter when a protected tree:

1. Interferes with traffic and circulation safety pursuant to CMC 8.40.070;

2. Poses an imminent threat to the public safety or general welfare pursuant to CMC 8.40.030(c);

3. Poses an immediate threat to existing electrical power or communication lines;

4. Is planted, grown, or held for sale by a nursery, tree farm, orchard or similar commercial operation;

5. Is determined by an ISA certified arborist (“arborist”) to be a host for a parasitic plant or insect which may endanger other trees in the area and cannot reasonably be controlled through less drastic means; or

6. Is determined by an arborist to be dead or dying and as a result has become hazardous or unsightly, and provides limited habitat value. [Ord. 12-4. DC 2012 § 122-826].

A. Application Contents. Each tree permit application shall include the following information and materials.

1. General Content Requirements. The application shall include the required information contained in the application checklist on file with the planning division, and shall include an arborist’s report in compliance with CDC 18.310.040, and be accompanied by the required application fees set forth in the city’s fee schedule.

2. Homeowners’ Association Approval. If the site is subject to conditions, covenants, and restrictions (CC&Rs) that address tree removal and are administered by an active homeowners’ association, the application shall include a letter from the homeowners’ association authorizing the tree removal.

B. Application Filing. An application for a tree permit shall be submitted at the time of application for any required permit. [Ord. 12-4. DC 2012 § 122-827].

A tree permit application associated with a planning permit application shall include a report from an ISA certified arborist (“arborist”) approved by the city and paid for by the applicant, in compliance with the following requirements:

A. Minimum Information. The arborist’s report shall include the following information:

1. Botanical and common names of trees by tree number;

2. Location of trees by tree number;

3. Circumference at 54 inches above the ground and height by tree number, with equivalent diameter measurement;

4. Height;

5. Dripline radius by tree number (measure longest radius);

6. Condition by tree number; and

7. Recommendations.

B. Determination of Tree Condition. The information on tree condition in the report shall include:

1. A Rating System. The condition of each tree (excellent; good; fair to good; fair; fair to poor; or poor) based on the following factors:

a. The condition and environment of the root crown (also roots, if applicable);

b. The condition of the trunk, including decay, injury, callusing or presence of fungus sporophores and bacteria;

c. The condition of the limbs, including strength of crotches, amount of deadwood, hollow areas, and whether excessive weight is borne by them;

d. The condition and growth rate history of the twigs, including pest damage and diseases; and

e. Grade changes and presence of watercourses or ponding within the dripline.

2. Formulation of Tree Recommendation. Using the above factors, the arborist shall describe the tree condition, as follows:

a. Live crown ratio (the ratio of a tree’s live crown to its total height).

b. Structural condition, including root crown, trunk and limb ratings (this is separate from the tree’s vigor condition, which relates more to twigs, foliage, and growth rate).

c. The structure of the root crown and trunk are of primary importance and take precedence over any other factor.

C. Arborist Recommendations. The arborist recommendations shall address:

1. Measures by tree number that help improve condition ratings of individual trees, such as remedial maintenance, horticultural practices, mulch, and watering.

2. Preservation measures for each tree to remain.

3. Replacement ratios for the removal of trees pursuant to CDC 18.310.060 (Replacement trees). [Ord. 12-4. DC 2012 § 122-828].

The following procedures shall apply to all encroachments in the tree protection zone (TPZ) associated with development and construction activities. All tree permits related to such activities shall incorporate the provisions of this chapter unless otherwise recommended by the arborist and approved by the planning division and/or public works department.

A. Trenching Procedures. Trenching within the TPZ, when permitted, shall only be conducted with hand tools, or use of an air spade, or as otherwise directed by an arborist, to avoid root injury.

B. Cutting Roots.

1. Minor roots less than one inch in diameter may be cut, but damaged roots shall be traced back and cleanly cut behind any split, cracked or damaged area.

2. Major roots over one inch in diameter may not be cut without approval of an arborist. Depending upon the type of improvement being proposed, bridging techniques or a new site design may need to be employed to protect the root and the tree.

C. Ground Surface Fabric. If any ground surface fabric within the TPZ is removed for any reason, it shall be replaced within 48 hours.

D. Irrigation Systems. An independent low flow drip irrigation system may be required for establishing drought-tolerant plants within the TPZ. Irrigation shall be gradually reduced and discontinued over a two-year period.

E. Plant Material Under Oaks. Planting live material under native oak trees is generally discouraged, and will not be permitted within six feet of a trunk of a native oak tree with a diameter of 18 inches or less at 54 inches above ground, or within 10 feet of a trunk with a diameter of more than 18 inches at 54 inches above ground. Only drought-tolerant plants will be permitted within the protected zone of native oak trees.

F. Temporary Protective Fencing During Construction or Grading Activities.

1. Type of Fencing. Prior to construction or grading activities, a minimum five-foot-high chain link or substitute fence shall be installed at the outermost edge of the TPZ for each protected tree or groups of protected trees. Exceptions to this policy may occur in cases where protected trees are located on slopes that will not be graded. Approval shall be obtained from the planning division prior to omitting fences in any area of the project.

2. Fence Installation. Temporary fences shall be installed in accordance with an approved fencing plan prior to the commencement of any grading operations or other such time as determined by the review authority.

3. Signing. Signs shall be installed on the fence in four equidistant locations around each TPZ. The size of each sign shall be a minimum of two feet by two feet and shall contain the following language:

“WARNING: THIS FENCE SHALL NOT BE REMOVED OR RELOCATED WITHOUT WRITTEN AUTHORIZATION FROM THE CONCORD PLANNING DIVISION”

Signs placed on fencing around a grove of protected trees shall be placed at approximately 50-foot intervals.

4. Fence Removal. Fences shall remain in place throughout the entire construction period and shall be removed at the end of construction.

G. Retaining Walls and Root Protection. Where a building permit has been approved for construction of a retaining wall within the TPZ, the applicant shall provide for the immediate protection of exposed roots from moisture loss during the time prior to the completion of the wall. The retaining wall shall be constructed within 72 hours after completion of grading.

H. Preservation Devices. If required, preservation devices such as aeration systems, tree wells, drains, special foundation systems, special paving, and cabling systems must be installed per approved plans and certified by an arborist.

I. Grading.

1. Every effort shall be made to avoid cut and/or fill slopes within or in the vicinity of the TPZ.

2. No grade changes are permitted which cause water to drain to within twice the longest radius of the TPZ.

3. No grade changes are permitted that will lower the ground on all sides of the TPZ.

J. Chimney Locations. A chimney for a wood-burning fireplace or stove shall not be located within or beneath the canopy of a tree or in a location where sparks emitted from the chimney may damage a tree.

K. Certification Letters. Certification letters shall be required for all regulated activities within the TPZ. The arborist shall be required to submit a certification letter to the planning division within five working days of completing any regulated activity, attesting that all work was conducted in accordance with the appropriate permits and the requirements of this chapter.

L. On-Site Information. The following information shall be posted on site during any construction activity within the TPZ:

1. Arborist’s report and any subsequent modifications;

2. Tree location map with a copy of the tree fencing plan;

3. Tree permit;

4. Approved construction plans;

5. Tree preservation guidelines; and

6. Approved planting and irrigation drawings.

M. Information Standards. The applicant shall be responsible for informing all subcontractors and individuals who will be performing work around protected trees of the requirements of this section and the conditions of approval for the project. This information shall be provided in writing to the subcontractors and employees by the general contractor or applicant.

N. Utility Trenching Pathway Plan. As a condition of the tree permit, the applicant shall be required to submit a utility trenching plan with the improvement or civil plans, prior to issuance of permits.

1. Contents. The trenching pathway plan shall depict all of the following systems: storm drains, sewers, easements, water mains, area drains, and underground utilities. Except in lot sale subdivisions, the trenching pathway plan must show all lateral lines serving the buildings. The trenching pathway plan must include the surveyed locations of all protected trees as well as an accurate plotting of the TPZ.

2. Standards for Plan. The trenching pathway plan shall consider the following guidelines:

a. The trenching pathway plan shall be developed to avoid encroaching into the TPZ on its path from the street to the building.

b. Where it is not possible to avoid encroachment, the design shall minimize the extent of such encroachment. Encroachments and mitigation measures shall be addressed in a supplemental arborist’s report.

O. Final Certification of Tree Work. All of the tree preservation measures required by the conditions of approval and the arborist reports shall be completed and certified by the arborist prior to issuance of an occupancy permit.

P. Pruning. Pruning of trees that are retained shall be conducted in compliance with International Society of Arboriculture (ISA) best management practices and ANSI A300 or other applicable and comparable accepted standard. [Ord. 12-4. DC 2012 § 122-829].

Where it has been determined that preservation of protected trees associated with a construction and/or development project is infeasible, replacement plantings shall be required as follows:

A. Replacement Ratio. The review authority shall condition any tree permit for the removal of protected trees with replacement trees, at a minimum ratio of three replacement trees for every one that is removed. The number and size of the replacement trees shall be determined based on the age, condition, and species, and loss of canopy cover for each tree removed.

B. Location and Specifications.

1. Replacement trees shall be planted on site, except in instances where on-site planting and future tree survival is shown to be infeasible, in which case the review authority shall authorize other off-site locations where maintenance will be guaranteed.

2. All replacement trees shall be of the same species as the trees being replaced, except when a replacement tree is approved in a location characterized by nonnative species, such as within a narrow roadway median where existing trees are ornamental nonnatives, or as part of residential lot landscaping.

3. Up to 50 percent of the required replacement trees may have a five-gallon container size when an arborist determines that long-term tree health and survival will be improved by starting with a smaller container size.

4. Replacement trees shall be in addition to any trees required by any other provisions of this title (e.g., required parking lot landscaping or street trees).

C. Revegetation Program. The review authority may authorize implementation of a revegetation program based upon an arborist’s determination that a revegetation program is superior to use of replacement trees.

1. The applicant shall enter into a written agreement with the city that sets forth the requirements of the revegetation program.

2. A performance security or bond for 100 percent of the cost of the revegetation program shall be required to ensure that the agreement is fulfilled.

3. The revegetation program shall propagate trees from seed using currently accepted methods, and shall identify the seed source of the trees to be propagated, the location of the plots, and the methods to be used to ensure the program’s success.

4. A revegetation program shall not be considered complete until the trees to be propagated have survived in a healthy state for a minimum of 10 years, unless alternative success criteria have been approved. [Ord. 12-4. DC 2012 § 122-830].

Each tree permit application associated with a development or construction project shall be reviewed, and then approved or denied, in compliance with the following criteria:

A. Criteria for Evaluation. The following criteria shall be used to support the findings required by subsection (D) of this section for the approval of a tree permit.

1. The extent of proposed building or development activity that does not require the removal of protected trees, relative to the extent of proposed building or development activity that requires such removal;

2. Design features of the project in comparison with other existing or approved projects in Concord that have (or had) protected trees on their sites;

3. Factors that are unique to the site, such as topographic constraints, lot configuration and other physical limitations;

4. The overall health and structural condition of the potentially impacted protected trees;

5. The approximate age of each protected tree compared with the average life span for each species;

6. The number of healthy, protected trees that the site will support, with and without the proposed development;

7. The effect of tree removal on soil stability/erosion, particularly near watercourses or on steep slopes; and

8. Whether any alternatives would allow for the preservation of the protected tree.

B. Criteria for Removal.

1. The age of the protected tree(s) with regard to whether removal would encourage healthier, more vigorous growth of younger similar trees in the area;

2. The number of existing protected trees in the area and the effect of removal on the public health, safety, and general welfare of the area;

3. The potential for the protected tree to become a public nuisance or interfere with utility service(s) and existing structures;

4. Present and future shade potential with regard to solar heating and cooling.

C. Criteria for Encroachment. Whether the degree of encroachment is likely to result in the subsequent decline of the affected protected tree, create a future risk to public safety, or pose a hazard to adjacent structures.

D. Findings for Approval. In approving a tree permit, the review authority shall find that the tree permit:

1. Is consistent with the provisions of this chapter and will not be detrimental to the public health, safety or welfare;

2. Is consistent with the appropriate criteria in subsections (A) and (B) of this section (decision); and

3. Measures have been incorporated into the project or permit to mitigate impacts to remaining trees or to replace the trees that have been removed.

E. Findings for Denial. A tree permit shall be denied if the review authority finds:

1. Removal or damage of a healthy tree can be avoided by:

a. Reasonable redesign of the site plan prior to construction; or

b. Trimming, thinning, tree surgery, or other reasonable treatment.

2. Adequate provisions for drainage, erosion control, land stability, windscreen, or buffers along the road and between neighbors have not been made where these problems are anticipated as a result of the removal; or

3. The tree to be removed contains an active nest of a bird covered by the Migratory Bird Treaty Act that has been identified through the project environmental review process, and a qualified professional has determined that the relocation of the nest without damage to the nestlings is not possible. In this case, tree removal shall be delayed until nesting is complete.

F. Limitation on Approved Activities. A permit shall not be issued for temporary parking, or the storage of vehicles, trailers, equipment, construction materials, or temporary structures within the protected zone of a protected tree. [Ord. 12-4. DC 2012 § 122-831].

The approval of a tree permit shall include conditions of approval as necessary to ensure compliance with CDC 18.310.060 (Replacement trees) and shall include the following requirements:

A. Expiration/Extension. Except where otherwise provided by this chapter, a tree permit shall be exercised within six months from the date of approval or other time limit established through a concurrent land use permit approval. Time extensions, for up to a total of two additional years, may be granted in compliance with Chapter 18.405 CDC (Permit Application Filing and Processing). A tree permit not exercised within its time limits shall expire in compliance with Division VII of this title (Permits and Permit Procedures).

B. Performance Guarantee. The review authority may require that a monetary security deposit be posted and maintained where deemed necessary to ensure the preservation of protected trees during construction and the completion of required mitigation measures. The deposit shall be posted in a form acceptable to the city, prior to any grading, movement of heavy equipment onto the site, or issuance of any permits. Each violation of a tree permit condition shall result in forfeiture of a portion or the entirety of the deposit, at the discretion of the review authority. This determination may be appealed in compliance with Division VIII of this title (Administration).

C. Revocation. A tree permit may be revoked or modified, as provided in Chapter 18.540 CDC (Enforcement), if it is found that the tree removal, relocation, or protection activities:

1. No longer support the original findings;

2. Resulted from misrepresentation or fraud;

3. Have not met, or have violated any condition of approval; or

4. Constitute a nuisance.

D. Stop Work Orders. Whenever any construction or work is being performed contrary to the provisions of this chapter or applicable conditions of approval, a written notice may be served on the responsible party to stop work on the project on which the violation has occurred or upon which the danger exists. The notice shall state the nature of the violation and the risk to the trees. No further work shall be allowed until the violation has been corrected.

E. Civil Penalties. Any person, including but not limited to the property owner, the person performing the work and/or any other responsible person, who violates any provision of this chapter or any condition imposed upon any permit issued hereunder shall be liable to the city for a civil penalty of three times the damage caused to a protected tree, or $5,000, whichever is greater. For purposes of calculating the damage to the protected tree, the then-current edition of the “Guide for Establishing Values of Trees and Other Plants” by the Council of Tree and Landscape Appraisers shall be presumed to provide the appropriate basis for determining damages. [Ord. 12-4. DC 2012 § 122-832].