Chapter 20.40
LANDSCAPING STANDARDS
Sections:
20.40.020 Application of requirements.
20.40.030 Landscaping—Screen types and descriptions.
20.40.040 Landscape screening standards.
20.40.060 Adjustment of landscape requirements.
20.40.070 Landscape maintenance.
20.40.080 Performance assurance.
20.40.010 Purpose.
The purpose of the landscaping and screening requirements of this chapter are to increase compatibility between different intensities of land uses by providing visual barriers that interrupt the barren expanse of paved parking lots, screen undesirable views of surrounding properties, and provide a visual separation and physical buffer between varying intensities of abutting land uses. It is the intent of these requirements to reduce the impact of erosion and stormwater runoff; provide impervious surfacing to allow natural groundwater recharge; reduce heat, air and noise pollution; promote safety through reduced glare and reduction of congestion; visual separation of traffic movement; and preserve and enhance the ecology of the region and the natural character of the community. (Ord. TLS 12-04-06B Exh. B (part): Ord. TLS 00-02-06 Exh. B (part): Ord. TLS 97-10-71B Exh. H (part))
20.40.020 Application of requirements.
A. This chapter shall apply to all permitted, accessory, and conditional uses. Landscape plans shall be submitted with a development permit application prior to the issuance of any building permit or other land use action. This chapter does not apply to:
1. Farms and accessory uses associated with farming;
2. Single-family residential dwellings, duplexes and their accessory uses when not developed as part of an overall development, i.e., subdivisions or planned developments, and while used for those purposes;
3. Subdivision(s) and short subdivision(s), except subdivision entrance signs, or landscape design standards required elsewhere in the DCC;
4. Remodels representing less than fifty percent of the valuation of the structure as determined by using the most recent IBC construction tables, or remodels adding less than twenty percent of gross floor area, whichever is greater; and
5. Changes or expansions in use(s) requiring less than five parking stalls or less than ten percent of the required parking stalls.
B. The review authority shall review and may approve, approve with modifications or disapprove the landscape plans for all developments in accordance with the provisions of this chapter. The review authority, upon recommendation by the county engineer, may permit a portion of the required landscaping within the county right-of-way when the landscaping will separate roads from a sidewalk or trail facilities. Other alternative landscaping (as set forth in DCC Section 20.40.060) may be allowed by the review authority when the overall site development plan, as proposed by the applicant, provides equal or better results than required by this chapter.
C. The following terms are used in applying the landscaping standards as enumerated within this chapter:
1. “Landscaping” shall mean an area devoted to or developed and maintained with plantings, lawn, groundcover, gardens, trees, shrubs and other plant materials, decorative outdoor landscape elements, garden ponds or pools, fountains, water features, paved or decorated surfaces of rock, stone, brick, block or similar material (excluding driveways, parking, loading or storage areas), and sculptural elements;
2. “Landscaping, interior” shall mean a landscaped area or areas within the shortest circumference line defining the perimeter or exterior boundary of the parking or loading area, or similar paved area, excluding driveways or walkways providing access to the facility (as applied to parking and loading facilities or to similar paved areas);
3. “Landscaping, perimeter” shall mean a landscaped area adjoining and outside the shortest circumference line defining the exterior boundary of a lot, parking or loading area, or similar areas, excluding driveways or walkways providing access to the facility (as applied to parking and loading facilities or to similar paved areas).
D. All required landscaping shall be maintained by the landowner or, in the case of streetscape landscaping, by the adjacent landowner, unless it is part of a county maintenance program. (Ord. TLS 12-04-06B Exh. B (part): Ord. TLS 00-02-06 Exh. B (part): Ord. TLS 97-10-71B Exh. H (part))
20.40.025 Landscape plan.
All landscaping plans shall be a scaled drawing submitted to and approved by the review authority when applicable and shall be consistent with the provisions of this chapter. The landscape plan designer preparing the plan shall either be a licensed landscape architect, Washington State certified nurseryman, Washington State certified landscaper, or a person with a minimum of four years experience and as approved by the director. At a minimum, the landscape plan shall contain:
A. Plant list including:
1. All plant materials to be used, keyed to plan(s) and defined by botanical and/or common name;
2. Quantity and type to be used;
3. Natural features or vegetation left in natural state;
4. Size of material to be planted (deciduous trees by caliper), evergreens, small flowering and ornamental fruit trees; and
5. Ultimate sizes of each plant and time to reach maturity.
B. Landscape design must include:
1. Location and size of all existing and future planting areas on site;
2. Indication of screening and buffer plantings required by ordinance;
3. Impervious surfaces;
4. Natural or manmade features and water bodies;
5. Existing or proposed structures, fences and retaining walls;
6. Location and spacing of each plant to be planted, shown to scale;
7. Designated recreational open space areas, pedestrian plazas or green areas;
8. Name and address of person, firm or organization preparing landscape plans;
9. An irrigation plan or specified method of watering and the type and location of all proposed lighting shall be included; and
10. Specifications for site soil amendments and mulching within required landscaping areas consistent with the minimum requirements of DCC Section 20.40.070(E).
C. A person certified in accordance with this section shall submit (within thirty days of a completed installation) a signed affidavit that the landscaping has been installed per the plan.
D. The landscape plan shall be submitted with the development application and approved prior to the issuance of a building permit or in conjunction with the development permit.
E. Any amendment to a landscape plan shall cause the plan to be resubmitted to scale in accordance with this section pursuant to the requirements of this chapter and shall be approved by the director prior to planting of any materials. Requests for modifications are classified under DCC Section 14.10.020. (Ord. TLS 12-04-06B Exh. B (part): Ord. TLS 00-02-06 Exh. B (part): Ord. TLS 97-10-71B Exh. H (part))
20.40.030 Landscaping—Screen types and descriptions.
All proposed plant material, sizes and characteristics shall be in accordance with general accepted landscaping standards and requirements of the industry, the American Association of Nurserymen Standards (ANSI 2601-1973) and other accepted practices. The following landscaping types required in DCC Section 20.40.040 are set forth below:
A. Type I: Screen. Type I landscaping is intended to provide a very dense sight barrier to significantly separate incompatible uses and land use districts. Existing natural buffers are encouraged but may need additional width or be augmented with additional landscaping features which may be selected to provide the required sight barrier.
1. All plant materials and living groundcover must be selected and maintained so that the entire landscape area will be covered a minimum of seventy-five percent within five years, with maximum coverage in eight years.
2. Any combination of trees (deciduous or evergreen), shrubs, earthen berms and related plant materials or design; provided, that the resultant effect is sight-obscuring from adjoining properties.
3. All trees and shrubs must be capable of growing to a minimum of six feet and three and one-half feet in height respectively.
B. Type II: Streetscape. Type II landscaping is intended to create a visual separation between uses from roads, and create visually aesthetic roadway corridors to help promote linkages between neighborhoods, commercial, industrial and recreational areas.
1. Deciduous trees and a combination of shrubs and/or groundcover approved by the review authority and as set forth herein:
a. Trees shall be a minimum of six feet in height at the time of planting;
b. Planted at intervals no greater than fifty-foot centers; and
c. Trees shall not be located closer than three feet to the curb and/or a sidewalk.
2. Shrubs shall be a minimum of one and one-half feet in height at the time of planting and may be dispersed throughout the landscaped planting area or in confined pockets or nodes.
3. Groundcover shall be designed to cover sixty percent of the required area. Groundcover shall consist of grass, shrubs, vines or other similar living groundcover. The remaining area may be covered with bark, rock or other similar material. These areas may also contain trees, shrubs, and other permitted plant materials and pedestrian amenities (i.e., benches); however, areas planted in grass shall be designed and constructed in a manner that will make possible normal maintenance such as mowing and watering. Groundcover shall be planted so that a minimum of seventy-five percent of the area is covered at maturity within five years.
4. Street trees shall be planted adjacent to the right-of-way, but not closer than three feet to a public sidewalk or curb. In no case shall sight-obscuring landscaping be located within the clear view triangle area as set forth in DCC Chapter 18.16.
5. It shall be the responsibility of the owner(s) of the lot adjacent to the streetscape area to maintain the trees and planting area in good growing condition and to replace dead or dying trees with similar tree or shrub species. The county shall have the right to prune and maintain trees and shrubs within the lines of the right-of-way, clear view triangle and other public areas as may be necessary to ensure public safety.
C. Type III: Perimeter Landscaping. Type III landscaping is intended to provide landscaping on the perimeter boundary of the site and provide a visual separation of uses from adjacent uses and parking areas.
1. A combination of deciduous and/or evergreen trees, shrubs, and groundcover.
a. No more than sixty percent of the trees shall be deciduous;
b. Trees shall be a minimum of six feet in height at the time of planting; and
c. Planted at intervals no greater than thirty feet on center, unless plantings are clustered into groups, then the planting intervals shall be planted at intervals no greater than ninety feet.
2. Shrubs shall be a minimum of one and one-half feet in height at the time of planting with approved living groundcover. Plant materials shall be planted so that the ground will be covered a minimum of seventy-five percent within five years.
3. Earthen berms with grass, vegetative groundcover or other landscaping features should be designed with the required landscaping standards of this chapter, provided the resultant effect would provide a pedestrian friendly environment and visual relief where clear sight is required and can be achieved.
D. Type IV: Landscaping, Open. Type IV landscaping is intended to provide visual relief where clear sight is desired, pedestrian plazas, green areas, around signs, intersections, buildings or other similar areas.
1. A combination of evergreen or deciduous trees or shrubs and groundcover planted adjacent to buildings, structures or other features in the following areas and shall meet the criteria as prescribed herein:
a. At the main entrance and frontage of the building;
b. Adjacent to a public road; and/or
c. Adjacent to designated public spaces, plazas and/or patios; and
d. Around signs or other features.
2. A minimum of thirty percent of the area as measured along the length of a building or structure shall be planted and landscaped in areas identified in subsections (D)(1)(a) through (d) of this section.
3. The landscape area shall not be located greater than fifteen feet from the building or structure.
4. Accessory buildings associated with the primary use shall be exempt from the above requirements, except as provided elsewhere in this title.
5. Landscaping located at road intersections or within a clear view triangle shall not exceed three and one-half feet in height as measured from road grade and shall meet the minimum criteria established in DCC Chapter 18.16 for clear view triangle.
E. Type V: Landscaping, Parking. Type V landscaping is intended to provide visual relief and shade in parking areas. Up to one hundred percent of the required trees proposed for the parking area may be deciduous.
1. Required Amount.
a. If the parking area contains less than fifty parking spaces, at least seventeen and one-half square feet of landscape area must be provided as described in subsection (E)(4) of this section for each parking stall proposed.
b. If the parking area contains more than fifty, but less than one hundred parking spaces, the director shall determine the required amount of landscaping by interpolating between seventeen and one-half and thirty-five square feet for each parking stall proposed. The area must be landscaped as described in subsection (E)(4) of this section.
c. If the parking area contains more than ninety-nine parking spaces, at least thirty-five square feet of landscaping must be provided as described in subsection (E)(4) of this section for each parking stall proposed.
2. Each area of landscaping must contain at least one hundred square feet of area and dimension shall not be less than four feet in any direction. The area must contain at least one tree six feet in height and with a minimum size of one and one-half inches in caliper measured six inches above existing grade if deciduous at the time of planting. The remaining ground area must be landscaped with plant materials.
3. A landscaped area must be placed at the interior end of each parking row in a multiple lane parking area. Each area must be at least four feet wide and must extend the length of the adjacent parking stall(s).
4. One shade tree shall be planted within the interior of the off-street parking area for every ten parking stalls.
a. All landscaped islands must have a minimum depth of topsoil of two feet for shrubs and four feet for trees, unless poor drainage conditions exist which would require modifications which shall be approved by the review authority.
b. All landscaped islands shall be planted with a combination of shade trees, shrubs or living groundcover. This area may contain ornamental trees and shrubs if appropriate. All planting must be in the central portion of the island.
c. Screen planting of a dense evergreen material not less than five feet in height at the time of maturity shall be provided in any locations where lights from vehicles within the off-street parking area may shine directly into windows of adjacent residential buildings. In lieu of screen planting, up to fifty percent of the required landscaping may be subtracted when a solid rock, masonry or wood fence is constructed, provided the fence is not less than forty-two inches high nor more than five feet high.
d. A screen planting of dense evergreen material not less than five feet high at the time of planting shall be required where overhead illumination is located within the off-street parking area and may shine directly into windows of adjacent residential buildings. The review authority may require a greater height if it is determined that the screen planting of five feet high does not properly screen the overhead illumination from adjacent residential buildings. Parking lot lights will not be permitted to shine over property boundaries. (Ord. TLS 12-04-06B Exh. B (part): Ord. TLS 00-02-06 Exh. B (part): Ord. TLS 97-10-71B Exh. H (part))
20.40.040 Landscape screening standards.
Landscaping shall be provided in all developments subject to this chapter and as set forth below, except as otherwise enumerated within the DCC. Where the width of a required planting strip exceeds the setback requirement for any structure or parking setback established in DCC Title 18, subject to this chapter, the setback shall be increased to provide the full width of planting strip unless otherwise modified in accordance with DCC Section 20.40.060.
A. District Landscaping Designations and Minimum Width. The following standards listed below indicate the type and width of landscaping required for various proposed uses, depending on the zoning district, type of use and zoning of adjacent parcels, or as enumerated elsewhere in this title:
1. Type IV landscaping shall be provided for all buildings, structures, signs, road intersections and plaza/green areas as set forth in DCC Section 20.40.030(D), except when associated with single-residential dwellings.
2. Type V landscaping shall be provided for all off-street parking areas as set forth in DCC Section 20.40.030(E).
3. RSC District.
a. Front yard: minimum eight-foot width, Type II landscaping;
b. Rear yard: minimum ten-foot width, Type III landscaping; minimum fifteen-foot width, Type I landscaping if located adjacent to a residential use, agriculture or other low intensity use, except as otherwise determined by the director;
c. Side yard: minimum ten-foot width, Type III landscaping; minimum is fifteen-foot width, Type I landscaping if located adjacent to a residential, agriculture or other low intensity use, except as otherwise approved by the director; and
d. Adjacent to buildings or structures: minimum five-foot width, Type IV landscaping;
e. Uses within the RSC district shall be exempt from subsection (A)(2) of this section.
4. Conditional Uses, Except Where Enumerated Elsewhere in This Chapter. The review authority may increase the minimum width of the landscaped area and type of planting if the use is located adjacent to a lower intensity use.
a. Front yard: minimum eight-foot width; Type II;
b. Rear yard: minimum five-foot width, Type III;
c. Side yard: minimum five-foot width, Type III; and
d. Adjacent to buildings or structures: minimum five-foot width, Type IV landscaping.
5. I-G District, Rural and Agriculture Resource Industries.
a. Front yard: minimum ten-foot width except as enumerated elsewhere in DCC Title 18 for agricultural resource industry, Type II; minimum twenty-foot width, Type I if adjacent to residential districts and/or agricultural districts;
b. Rear yard: minimum five-foot width, Type III if adjacent to an urban commercial zoning district; minimum ten-foot width, Type I if adjacent to a residential district;
c. Side yard: minimum five-foot width, Type III if adjacent to an urban commercial zoning district; minimum ten-foot width, Type I if adjacent to a residential district; and
d. Adjacent to buildings or structures: minimum five-foot width, Type IV landscaping.
B. Landscape Standards for Signs Including Permanent Subdivision Signs. Entrance signs shall be landscaped with Type IV landscaping and have a minimum landscaped area of fifty square feet. (Ord. TLS 12-04-06B Exh. B (part): Ord. TLS 00-02-06 Exh. B (part): Ord. TLS 97-10-71B Exh. H (part))
20.40.060 Adjustment of landscape requirements.
A. An alternative landscaping plan for an overall site development may be submitted and approved by the review authority when the landscaping plan as proposed meets the minimum standards and general intent of this chapter. The landscaping plan shall be processed simultaneously with the overall site development plan.
B. The review authority may authorize reduced or expanded widths of plantings or may waive or require supplementation of some of the landscaping requirements in the following instances:
1. When the inclusion of significant existing vegetation located on the site would result in as good as or better satisfaction of the purposes of this chapter;
2. When the landscaping would interfere with the adequate flow of stormwater runoff, as determined by the county engineer along drainage easements and/or when the landscaping would interfere with the adequate treatment of stormwater in grassed percolation areas;
3. Requests for modifications to landscape plans under this subsection are classified in accordance with DCC Section 14.10.020.
C. Combined Landscaping and On-Site Stormwater Facilities. A landscape plan which incorporates a minimum of fifty percent of the area dedicated for on-site stormwater facilities with required landscaping shall be eligible for a ten percent reduction in the overall landscaped area required under DCC Section 20.40.040. Shrub and living groundcover coverage standards may be reduced so that a minimum of fifty percent of the ground will be covered within five years of installation for Type II, III, and V landscaping. Where living groundcover is decreased under this provision, the landscape plan shall include a narrative addressing the long term maintenance of the landscaped area for weeds, windblown refuse and leaf litter. The design of the combined landscape/stormwater facilities must meet the intended purpose of each landscape type under DCC Section 20.40.030.
The landscape plan designer, in applying the ten percent reduction to each type of landscaping under DCC Section 20.40.030, must certify that sufficient area remains for the proposed plantings to grow to maturity under accepted nursery standards and practices. The engineer of record shall certify that the combined landscape and stormwater facilities meet Douglas County Code stormwater requirements and conform to the best management practices contained within the Eastern Washington Stormwater Management Manual (SWMMEW). Combined plans must be reviewed and accepted by the county engineer. If a controlled surface conveyance stormwater system designed by a qualified engineer in conformance with Douglas County stormwater requirements and the best management practices of the SWMMEW is feasible and approved for the site, it can provide an additional degree of flexibility for landscape plant material choices and landscape design options.
D. Low Water and Xeric Landscaping. The following landscaping alternative is not intended to be mandatory, but instead provide an alternative approach to the standard provisions of this chapter to provide sustainable landscapes that may reduce landscape maintenance costs, reduce the costs of watering and conserve water resources for the community. A landscape plan which incorporates the use of drought tolerant plant and native plant materials in conformance with the provisions of this section shall be eligible for a ten percent reduction in the overall landscaped area required under DCC Section 20.40.040. Landowners and developers who choose to utilize this section shall submit a landscape plan in conformance with DCC Section 20.40.025, in addition to a written narrative from the landscape plan designer which addresses how the plans conform to subsections (D)(1) through (5) of this section. A person certified in accordance with this chapter shall submit within thirty days of a completed installation a signed affidavit that the landscaping has been installed per the plan and written narrative.
1. Plant Selection, Sizing, and Minimum Area Coverage.
a. Inert groundcover such as bark, decorative rock, decomposed rock, or partially buried rock features may be incorporated into the landscape design. Shrub and living groundcover coverage standards may be reduced so that a minimum of fifty percent of the ground will be covered within five years of installation for Type II, III, and V landscaping.
b. Plant Lists. The plant material list is a guide to plants that require less water and is not intended as the final species list, the use of plants native to North Central Washington and low water use plants appropriate for this area. This plant material maximizes use of rainwater, reduces general maintenance needs, and reflects the natural surroundings of the region. Landscape plans under this section shall consist of plant material identified within the recommended plant lists and/or plant resources provided in this section or plant materials demonstrated by a design professional that require less than eighteen inches of water annually as provided below:
i. Native plants or low water use plants identified by a landscape architect; certified horticulturalist; or a biologist, botanist or ecologist with a degree in biology or ecology or a closely related field and a minimum of five years of work professional experience in Eastern Washington working in a position closely associated with native plant species; and
ii. Native and low water plants list maintained by Douglas County land services, as amended.
c. Turf or Grass Species Requirements. Cool season grasses that are not drought tolerant shall not exceed twenty-five percent of the landscaped area. Alternative drought tolerant species may be used and can exceed the twenty-five percent threshold. These species, or equivalent species determined by a landscape architect or horticulturist, include warm season grasses such as buffalo grass and blue grama, or cool season grasses such as reveille and tall fescue. Where turf or grasses are planted that require over eighteen inches of water annually, a minimum width of eight feet shall be required in order to provide for the efficient application of irrigation. Widths less than eight feet are permitted when turf drip systems are utilized.
2. Soil Amendments and Mulching Within Required Landscape Areas. Components of landscape areas which will be planted with native grasses, native shrubs or native perennials may not require the application of soil amendments or mulch, when the landscape plan designer determines that these materials are not necessary for the long term survival of these native species based upon an analysis of existing site conditions and soil characteristics.
3. Irrigation and Water Use for Landscape Features.
a. All landscaped areas must have installed a permanent underground irrigation system with an automatic controller plus an overriding rain switch, or an alternative irrigation method which provides sufficient water to ensure that the plants will establish and remain healthy. Irrigation systems should be adjusted seasonally to accommodate changing weather conditions.
b. The use of drip, bubbler, or subsurface drip systems shall be required for landscaping. Fixed or rotary spray heads are only permitted for lawn areas. Turf drip systems are encouraged.
c. Runoff and Overspray. Soil types and infiltration rate shall be considered when designing irrigation systems. All irrigation systems shall be designed to avoid runoff, low head drainage, overspray, or other similar conditions where water flows onto adjacent property, nonirrigated areas, walks, roadways or structures. Proper irrigation equipment and schedules, including repeat cycles, shall be used to closely match application rates to infiltration rates to minimize runoff. Special attention shall be given to avoid runoff on slopes and to avoid overspray in planting areas in median strips.
d. Irrigation shall occur during evening or morning hours and shall not occur between the hours of ten a.m. and six p.m. Watering schedules should apply water in a manner that waters deeply and less frequently, providing for deeper root systems.
e. Water features may be permitted where it can be determined that other water minimizing techniques have been used to compensate for the additional water use, i.e., only drought resistant turf species are utilized in the landscape areas. Water features shall have recirculating water systems.
4. Pruning and Maintenance.
a. Pruning. Pruning of trees shall be consistent with the standards of the International Society of Arboriculture, as of February 7, 2012, http://isa-arbor.com/. Some low water and xeric plants will require a programmatic approach to pruning for the long term health and sustainability of the plant. Where such pruning is necessary, pruning guidelines should be provided to the property owner or developer within the maintenance plan described within subsection (D)(4)(b) of this section.
b. Maintenance shall be in conformance with the maintenance provisions of DCC Section 20.40.070. Drought tolerant plant selections typically require less maintenance activities. However, a programmatic approach to the long term application of appropriate fertilizers and/or natural compost material to vegetation on site will assist with the long term sustainability of vegetation and decrease watering needs. The submission of landscape plans shall include a plan component which outlines recommendation for a long term maintenance plan that addresses fertilizers and/or compost material application appropriate to the landscape material chosen.
5. Comparable Water Use Design. Plants with similar water requirements should be grouped together in distinct hydrozones. Plants should be selected appropriately based upon their adaptability to the climatic, geological, and topographical conditions of the site. Protection and preservation of native species and natural areas is encouraged. Different areas receive different amounts of light, wind and moisture. Grouping together plants with similar sunlight and water requirements will minimize water waste. Place moderate water use plants in low lying drainage areas, near downspouts or along the side of other plants. Turf areas will require the most water, and shrub and perennial beds will require less water. Dry, sunny areas support low water use plants that grow well in this region’s climate. (Ord. TLS 12-04-06B Exh. B (part): Ord. TLS 00-02-06 Exh. B (part): Ord. TLS 97-10-71B Exh. H (part))
20.40.070 Landscape maintenance.
All landscaping shall be maintained for the life of the completed development.
A. The applicant and/or landowner shall follow accepted nursery standards and practices in the planting and maintenance of vegetation required by this chapter. During site development, care shall be taken not to compact the planting areas and compacted soils shall be loosened.
B. A permanently installed irrigation system shall be provided with adequate water pressure and coverage to serve all landscaped areas, except for areas with existing native species that are incorporated into the approved design.
C. The property owner shall keep the landscaped areas free of weeds, trash and replace any diseased, damaged, unhealthy or dead plants in conformance with the approved landscape plan. All landscape materials shall be pruned and trimmed as necessary to maintain a healthy growing condition. If the director determines the maintenance required under this subsection has not been performed, the county shall take enforcement action pursuant to DCC Chapter 14.92.
D. Planting areas shall be clearly separated from parking spaces and driveways by a raised curb, earthen berm or other suitable formal separation permanently affixed to the ground. Planting areas shall not have artificial impervious material underlying the top soil.
E. Soil Amendments and Mulching Within Required Landscape Areas.
1. Mulch.
a. Mulch shall be applied regularly to, and maintained in all, planting areas to assist soils in retaining moisture, reducing weed growth and minimizing erosion.
b. Mulches shall be applied to the following depths: three inches over bare soil and two inches where plant materials will cover.
c. Acceptable mulches include organic materials such as wood chips and shredded bark and inert organic materials such as decomposed lava rock, cobble, and gravel.
d. Nonporous materials, such as plastic sheeting, are not allowed in any areas of the landscape because of down-slope erosion and potential soil contamination from herbicide washing.
2. Soil Amendments.
a. Landscape areas shall be deep tilled to a depth of at least four to six inches to facilitate deep water penetration and soil oxygenation. Use of soil amendments is encouraged to improve water drainage, moisture penetration, soil oxygenation, and/or water holding capacity. Soil amendments are organic matter such as composted yard waste, sewer biosolids, and forestry by-products, but do not include topsoil or any mix with soil as an element. Sphagnum moss is not allowed because it provides only short-term benefits.
b. For all newly landscaped areas, organic matter (three to four cubic yards of organic matter per one thousand square feet of landscape area) shall be incorporated to a depth of at least four inches.
c. For newly landscaped areas where topsoil is limited or nonexistent, or where soil drainage is impeded due to subsurface hardpan, a minimum of six inches of sandy loam topsoil shall be spread in all planting and turf areas, in addition to the incorporation of organic matter into the top horizon of the imported soil. (Ord. TLS 12-04-06B Exh. B (part): Ord. TLS 97-10-71B Exh. H (part))
20.40.080 Performance assurance.
A. The required landscaping shall be installed prior to occupancy or the issuance of an occupancy permit, whichever occurs first, unless the director determines that a performance assurance device will adequately protect the interest of the county. In no case may the property owner/developer delay performance for more than one year, unless a time schedule is developed to phase in the landscaping and is approved by the director.
B. The review authority may require performance assurance as a warranty of plant survival. Such an assurance shall, if required, be in effect through one complete growing season following planting.
C. If a performance assurance device is required it shall be in substantial conformance with DCC Chapter 14.90. (Ord. TLS 12-04-06B Exh. B (part): Ord. TLS 97-10-71B Exh. H (part))