§ 23.05.048. Standards.

a.

Grading standards.

(1)

Excavation standards. All excavations are to be conducted in compliance with the provisions of California Building Code Section 1804.7, as modified by Section 19.03.010 of the Building and Construction Ordinance and the following standards:

(i)

No excavation shall be made with a cut face steeper in slope than two horizontal to one vertical, except under one or more of the following conditions.

(a)

The Director may permit an excavation to be made with a cut face steeper than two horizontal to one vertical if the applicant provides a slope stability analysis prepared by a geotechnical engineer or engineering geologist that the material making up the slope of the excavation and the underlying earth material is capable of standing on a steeper slope, and a certified soil and erosion control specialist or other qualified professional indicates, in writing, that either it is feasible to mitigate erosion and sedimentation impacts and that successful revegetation of the site with native plants can be accomplished or that due to the nature or composition of the cut slope, erosion and sedimentation measures and revegetation are unnecessary.

(b)

A retaining wall or other approved support which also mitigates visual impacts of the device is provided to support the face of the excavation.

(ii)

The Director may require an excavation to be made with cut face flatter in slope than two horizontal to one vertical if a slope stability analysis or other appropriate method of review indicates that the material in which the excavation is to be made is such that the flatter cut slope is necessary for stability, safety, or to prevent erosion and sedimentation and stormwater impacts.

(iii)

No cut slope shall exceed a height of 25 feet without intervening terraces having a minimum width of six feet. These terraces shall be vertically spaced at intervals of 25 feet except that for slopes less than 40 feet in vertical height the terrace shall be approximately at mid-height. Suitable access shall be provided to permit cleaning and maintenance. The Director may modify this requirement because of geologic or other special conditions.

(iv)

The border of all cut slopes shall be rounded off to a minimum radius of five feet to blend with the natural terrain.

(v)

All cut slopes shall be within parcels under common ownership unless written permission is granted by the adjacent owner.

(2)

Fill standards. All fills are to be conducted in compliance with the provisions of California Building Code Section 1804.7, as modified by Section 19.03.010 of the Building and Construction Ordinance and the following standards:

(i)

No fill shall be made which creates any exposed surface steeper in slope than two horizontal to one vertical, except under one or more of the following conditions:

(a)

A retaining wall or other approved support is provided to support the face of the fill which also mitigates visual impacts of the device.

(b)

The Director may permit a fill to be made which creates an exposed surface steeper in slope than two horizontal to one vertical (2:1) if a geotechnical engineering report demonstrates that slope stability will be ensured. The geotechnical engineer shall certify that the strength characteristics of the material to be used in the fill are such as to produce a safe and stable slope and that the areas on which the fill is to be placed are suitable to support the fill. Additionally, a certified soil and erosion control specialist or other qualified professional shall indicate in writing that it is feasible to prevent erosion and sedimentation impacts, and successful revegetation of the site can be accomplished. All such reports are subject to the approval of the Director.

(ii)

The Director may require that fill be constructed with an exposed surface flatter than two horizontal to one vertical (2:1) if a slope stability analysis or other appropriate method of review indicates that such flatter surface is necessary for stability, safety, or to prevent erosion and sedimentation impacts.

(iii)

Unless specified as a non-structural land reclamation, erosion control, or agricultural fill, all fills shall be placed, compacted, inspected, and tested in compliance with the following provisions:

(a)

The natural ground surface shall be prepared to receive fill by removing vegetation, non-complying fill, topsoil and other unsuitable materials. The surface shall be scarified to provide a bond with the new fill and where slopes are steeper than five horizontal to one vertical (5:1) and the height is greater than five feet, by benching into sound bedrock or other competent material as determined by the soils engineer. The bench under the toe of a fill on a slope steeper than five horizontal to one vertical (5:1) shall be at least 10 feet wide. The area beyond the toe of fill shall be sloped for sheet overflow or a paved drain shall be provided. When fill is to be placed over a cut, the bench under the toe of fill shall be at least 10 feet wide, but the cut shall be made before placing the fill. The soils engineer, engineering geologist, or both, shall certify that the bench is a suitable foundation for the proposed fill.

(b)

Except as otherwise permitted by the Director, no rock or similar irreducible material with a maximum dimension greater than six inches shall be buried or placed in fills. No organic material shall be permitted in structural fills. The Director may permit placement of larger rock when the soils engineer properly devises a method of placement, continuously inspects its placement, and approves the fill stability. The following conditions shall also apply:

1.

Prior to issuance of the grading permit, potential rock disposal areas shall be identified on the grading plan.

2.

Rock sizes greater than six inches in maximum dimension shall be 10 feet or more below grade, measured vertically.

3.

Rocks shall be placed so as to assure filling of all voids with well-graded soil.

(c)

A fill shall be spread in a series of horizontal lifts as specified by the geotechnical engineer or other approved professional approved by the Director. The distribution of material throughout each layer shall be free of lenses, pockets or layers of material differing substantially in texture or gradation from the surrounding material. All material shall be compacted into a fill of uniform moisture and density as specified in Subsection a(2)(iii)(d).

(d)

All fills shall be compacted to a minimum of 90 percent of maximum density as determined by ASTM D 1557-(latest edition) or other approved testing method giving equivalent test results. Field density shall be determined by ASTM D 1556-(latest edition) or other equivalent methods approved by the Director.

(e)

A field density test, as herein provided, shall be taken for each 24 inches of fill, or portion thereof, measured vertically from the lowest point of the area to be filled, and for each 200 cubic yards of fill placed unless a variation is recommended by the Soils Engineer and approved by the Director. In addition, in the case of a subdivision, field density tests shall be taken on lots which receive fill based upon the recommendations of a soils engineer.

(f)

All fills regulated by the Grading Ordinance shall be tested for relative compaction by a qualified geotechnical testing agency. Final reports, including a letter certifying compliance with the terms of the Grading Ordinance, and the grading permit, setting forth densities, relative compaction and other fill characteristics shall be prepared and signed by a geotechnical engineer or soils engineer. This report shall be submitted to and approved by the Director before any final approval of the fill is given and before any foundation construction begins except for the digging of trenches and placing of reinforcing steel.

(iv)

Fills toeing out on natural slopes which are steeper than two horizontal to one vertical shall not be permitted unless evaluated and approved by a geotechnical engineer or engineering geologist.

(v)

The border of fill slopes shall be rounded off to a minimum radius of five feet to blend with the natural terrain.

(3)

Grading setback standards. Cut and fill slopes shall be set back from site boundaries in compliance with the provisions of California Building Code Section 1804.7, as modified by Section 19.03.010 of the Building and Construction Ordinance and the following standards:

(i)

General. Setback dimensions shall be horizontal distances measured perpendicular to the site boundary. Setback dimensions shall be as shown in Figure 5-A.

Figure 5-A

(ii)

Top of cut slope. The top of the cut slopes shall not be closer to a site boundary line than one fifth of the vertical height of cut with a minimum of two feet and a maximum of 10 feet. The setback may need to be increased for any required interceptor drains or maintenance easements. The Director may approve adjustments as a condition of the permit, as required by individual site conditions.

(iii)

Toe of fill slope. The toe of fill slopes shall not be closer to the site boundary line than one-half the height of the slope with a minimum of two feet and a maximum of 20 feet. Where a fill slope is to be located near the site boundary and the adjacent off-site property is developed, or site conditions warrant, special precautions shall be incorporated in the work as the Director deems necessary to protect the adjoining property from damage as a result of such grading. These precautions shall include, but are not limited to the following:

(a)

Additional setbacks.

(b)

Provisions for retaining or slough walls.

(c)

Mechanical or vegetative treatment of the fill slope to minimize erosion.

(d)

Provisions for the control of surface waters.

(e)

Provisions for maintenance access.

(iv)

Modification of slope location. The Director may approve alternate setbacks. The Director may require an investigation and recommendation by a qualified engineer, engineering geologist, or erosion control specialist to demonstrate that the intent of this Section has been satisfied.

(v)

Distance from property line. No cut or fill shall be made which is sufficiently close to the property line to endanger any adjoining public or private property or structures without supporting and protecting such property or structures from any settling, cracking, or other damage which might result.

(4)

Landform alterations within public view corridors. Grading, vegetation removal, and other landform alterations shall be minimized on sites located within public view corridors. Where feasible, contours of finished grading are to blend with adjacent natural terrain to achieve a consistent grade and appearance.

(5)

Grading near watercourses. Grading, dredging or diking shall not alter any intermittent or perennial stream, or natural body of water, except as permitted through approval of a County drainage plan and a streambed alteration permit from the California Department of Fish and Game issued under Sections 1601 or 1602 of the Fish and Game Code. Watercourses shall be protected as follows:

(i)

Watercourses shall not be obstructed unless an alternate drainage facility is approved.

(ii)

Fills placed within watercourses shall have suitable protection against erosion during flooding.

(iii)

Grading equipment shall not cross or disturb channels containing live streams without siltation control measures approved by the Public Works Director in place.

(iv)

Excavated materials shall not be deposited or stored in or alongside a watercourse where the materials can be washed away by high water or stormwater runoff.

b.

Drainage standards. Designs for site area drainage and terraces shall be consistent with the Low Impact Development (LID) Handbook and the following minimum standards:

(1)

Design and construction. Drainage systems and facilities subject to drainage plan review and approval that are to be located in existing or future public rights-of-way are to be designed and constructed as set forth in the latest edition of the Public Works Department's Public Improvement Standards, or as per the project's conditions of approval. Applicants may request an adjustment pursuant to the Public Improvement Standards in order to allow for a design that is more compliant with LID practices. Other systems and facilities subject to drainage plan review and approval are to be designed in accordance with good engineering practices. The design of drainage facilities in new land divisions and other new development subject to Minor Use Permit or Development Plan approval shall maximize groundwater recharge through on-site or communitywide stormwater infiltration measures. Examples of such measures include constructed wetlands, vegetated swales or filter strips, small percolation ponds, subsurface infiltration basins, infiltration wells, and recharge basins. Where possible, recharge basins shall be designed to be available for recreational use.

(2)

Natural channels and runoff. Proposed projects are to include design provisions to retain natural drainage patterns and, when required, limit peak runoff to pre-development levels. To the maximum extent feasible, all drainage courses shall be retained in, or enhanced to appear in, a natural condition, without channelization for flood control. On downhill sites, encourage drainage easements on lower properties so that drainage can be released on the street or other appropriate land area below.

(3)

Best Management Practices (BMPs). All new development subject to drainage plan review shall use BMPs to address polluted runoff. BMPs shall be consistent with the guidance found in documents such as the LID Handbook. Such measures shall include, but not be limited to: minimizing the use of impervious surfaces (e.g., installing pervious driveways and walkways); directing runoff from roofs and drives to vegetative strips before it leaves the site; and/or managing runoff on the site (e.g., percolation basins); and other Low Impact Design (LID) techniques. The installation of vegetated roadside drainage swales shall be encouraged and, if used, calculated into BMP requirements. The combined set of BMPs shall be designed to treat and infiltrate stormwater runoff up to and including the 85th percentile storm event. The BMPs shall include measures to minimize post-development loadings of total suspended solids.

(4)

Runoff volume. Runoff conveyance systems shall be capable of carrying the computed runoff volume from a 25-year frequency storm or greater if deemed necessary by the Public Works Director. This may be reduced to a 10-year storm for small watersheds.

(5)

Interceptors. Concrete ditches, bio-swales or other approved methods capable of intercepting surface runoff waters shall be installed along the top of all cut slopes where the tributary drainage area has a slope 10 percent or greater and a horizontal projection greater than 40 feet.

(6)

Berms. Berms or drainage divides at least one foot high and three feet wide at the base shall be constructed at the top of all fill slopes where runoff would be directed towards the top of fill.

(7)

Over side drains. Over side drains shall be of concrete or corrugated metal pipe having a diameter required by runoff calculations, but not less than eight inches, and shall be aligned so as to minimize velocity at discharge points. Alternate designs, such as LID methods, approved by the Public Works Director may be permitted.

(8)

Inlets. Inlets shall be constructed of galvanized iron, or approved equivalent, and shall be provided with overflow structures.

(9)

Outlets. Outlet structures shall be provided with approved velocity reducers, diversion walls, rip-rap, concrete aprons or similar energy dissipaters where necessary and aligned to minimize downstream erosion and reasonably maximize recharge at discharge points, and shall be approved by the Public Works Director.

(10)

Dispersal structures. An approved drainage dispersal structure shall be constructed wherever it is necessary to convert channel flow to sheet flow.

(11)

Sensitive habitat and groundwater protection. Runoff from roads and development shall not adversely affect sensitive habitat, groundwater resources and downstream areas, and shall be treated to remove floatable trash, heavy metals and chemical pollutants as necessary prior to discharge into surface or groundwater.

(12)

Groundwater recharge methods. New development shall identify all methods to enhance groundwater recharge.

(13)

Impervious surfaces. New development shall be designed to minimize the amount of impervious surfaces in order to maximize the amount of on-site infiltration.

(14)

Rain gutters. Approved rain gutters shall be provided to receive all roof water and dispose of the water in a groundwater enhancing and non-eroding manner where the Director determines it to be necessary because of steepness of slope or presence of erodible materials. Direct connection of rain gutter outlets to impervious surfaces shall be minimized.

(15)

Building site drainage. All graded building pads shall slope a minimum of five percent for ten feet to an approved drainage device, or as approved by the Director. The drainage device shall be an approved system which conducts the water to a street, recharge area or drainage way. The top of footing stems or finish floor, if a concrete slab, shall extend above the top of street curb or inlet to the drainage device by a minimum of six inches plus two per cent of the distance from the footing to the drainage device or curb. The Director may allow two percent to be used, if, because of terrain or soils, five percent is not reasonably attainable or necessary.

(16)

Capacity of drainage devices. On graded sites, the Director may require that drainage devices calculated to convey runoff from a 25-year frequency storm or greater be installed, if deemed necessary to prevent erosion, to conduct stormwater around buildings or structures and to the nearest recharge area, drainage way, or as approved by the Public Works Director.

(17)

Appearance of drainage or recharge devices. Where drainage devices are highly visible from the street or located in the public viewshed, they shall be shielded from view, if practical. Where visible, drainage devices shall be compatible with the character of the area and the existing topography. Exposed concrete overside drains are prohibited within these situations unless a visual analysis indicates the prohibition to be unnecessary. If they are visible, the size shall be the minimum necessary to handle drainage and ensure ability to maintain all drainage devices which collect from the slopes, and shall convey drainage by means of underground pipes or rock-lined ditches or other approved materials to blend with the natural topography in character, color and design. Transitions from natural drainage courses to developed areas shall be accomplished with comparable landscaping and grading to blend with existing topography. Detention, retention, or recharge basins shall be designed as a visual and/or recreational amenity within a project whenever practical.

(18)

Areas subject to flooding. Buildings or structures are not permitted in an area determined by the Public Works Director to be subject to flood hazard by inundation, overflow, high velocity flows or erosion, except where the buildings or structures comply with the standards in Sections 23.07.060 et seq., and provisions are made to eliminate identified hazards to the satisfaction of the Public Works Director. These provisions may include providing adequate drainage facilities, protective walls, suitable fill, raising the floor level of the building or structure, or other means. The building and other structures (including walls and fences) shall be placed on the site so that water or mud flow will not be a hazard to on- or off-site structures or adjacent property. In the application of this standard, the Public Works Director shall enforce as a minimum the current federal flood plain management regulations as defined in the National Flood Insurance Program authorized by United States Code Title 42, Section 4001-4128 and contained in Title 44 of the Code of Federal Regulations, Part 59 et seq., which are hereby adopted and incorporated into this Title by reference as though they were fully set forth here.

(19)

Design of flood proofing measures. Flood proofing measures required by the Public Works Director shall be designed by a licensed architect or registered civil engineer.

(20)

Sub-drains. The Director may require the installation of approved sub-drains in areas where underground water is anticipated.

(21)

Runoff computations. Runoff computations may be made by the "rational method" except where specific methods for calculating individual residential retention basins have been adopted or with the approval of the Public Works Director.

(22)

Alternate designs. Alternate designs which provide equivalent safety and are approved by the Public Works Director may be used in lieu of those contained in this Section.

(23)

Hydromodification control. If the Director or Public Works Director has determined that the project could cause off-site erosion or adverse impacts to beneficial uses as a result of an increase in runoff rates and/or duration, the project shall incorporate site design Best Management Practices (BMPs) and, if necessary, structural and/or treatment control BMPs in order to match estimated post-development discharge rates as closely as possible to the estimated pre-development discharge rates..

(24)

Development adjacent to coastal bluffs. Stormwater outfalls that discharge to the bluff, beach, intertidal area, or marine environment are prohibited unless it has been demonstrated that it is not feasible to detain the stormwater on-site, or direct the stormwater to pervious land areas or the street, without causing flooding or erosion. In such instances, stormwater outfalls shall include filtration and treatment systems necessary to protect coastal water quality, be screened from public view using underground pipes and/or native vegetation screening of local stock, and receive all applicable agency approvals. Consolidation of existing outfalls shall be pursued where feasible. The drainage plan shall incorporate all reasonable measures to minimize increased erosion to the coastal bluff as a result of development.

c.

Erosion and sedimentation control standards. When required by Section 23.05.042 or elsewhere in this Title, erosion and sedimentation control plans, and implementation thereof, shall comply with the following standards:

(1)

Exposed man-made slopes shall be planted in permanent native vegetation to prevent erosion unless determined by the Director to be unnecessary.

(2)

Grading limits shall be staked out as shown on the approved plans before site disturbance begins. All land disturbance shall be restricted to this area.

(3)

All cuts, fills, and disturbed areas shall be planted, mulched and maintained, or otherwise protected from the effects of stormwater runoff and wind erosion. Permanent or temporary soil stabilization must be applied to denuded areas within 15 days after final grade is reached on any portion of the site. Denuded areas which may not be at final grade but which will remain undisturbed for longer than 60 days shall also be stabilized within 15 days. All mulching shall provide the same protection as that resulting from the application of two tons of straw mulch per one acre of surface area. All disturbed or denuded area created during the period between October 15 and April 15 of the following year shall be mulched or equally protected before quitting time each day.

(4)

All permanent slopes over three feet high shall be permanently revegetated with native plants to achieve a minimum of 70 percent coverage at 24 months. All slopes shall be maintained to assure the success of the plant material and the maintenance of the slope.

(5)

A minimum of one (1) one-gallon shrub shall be planted per 100 square feet of slope area where shrubs are appropriate to the area unless equivalent alternate measures are approved by the Director. Plant material must be selected to achieve 100 percent coverage of slope at maturity.

(6)

One (1) one-gallon tree shall be planted for every 500 square feet of slope area where appropriate to the area unless equivalent alternative measures are approved by the Director.

(7)

Temporary or permanent irrigation shall be provided to assure the successful establishment of the plant material.

(8)

Grading for agricultural practices to prepare a field or crop or range improvement practices shall be protected by recognized agricultural erosion and sedimentation control methods, such as those found in the Natural Resources Conservation Service (NRCS) Field Office Technical Guide (FOTG).

(9)

Grading permits may be conditioned to provide landscape and maintenance security.

(10)

Sediment basins shall be designed to trap and store all sediment particles larger than those passing a #200 testing sieve, from the peak discharge of a 25-year frequency storm.

(11)

Runoff shall enter and exit a basin through protected inlets and outlets as approved by the Director.

(12)

Sediment removal scheduling and sediment dispersal shall be included with the erosion and sedimentation control plan, subject to approval by the Director.

(13)

Temporary drainage control measures during construction shall avoid concentration of flow which may cause or exacerbate erosion and sedimentation.

(14)

Reserved.

(15)

Topsoil removed from the surface in preparation for grading and construction is to be stored on or near the site and protected from erosion while grading operations are underway, provided that such storage may not be located where it would cause suffocation of root systems of trees intended to be preserved or near a watercourse where sedimentation may occur. After completion of such grading, topsoil is to be restored to exposed cut and fill embankments or building pads to provide a suitable base for seeding and planting.

(16)

Native plant materials are required, in order to reduce irrigation demands. Where riparian vegetation has been removed, riparian plant species shall be used for revegetation.

d.

Stormwater pollution prevention standards. Projects requiring a SWPPP pursuant to Section 23.05.044 shall comply with the standards outlined in SWRCB General Construction Permit Number CAS000002, or any subsequent General Construction Permits that amend or replace Permit CAS000002. These standards include, but are not limited to, the following:

(1)

Discharge prohibitions.

(i)

Approval of a grading plan, stormwater pollution prevention plan, erosion and sedimentation control plan, or drainage plan does not constitute an exemption to applicable discharge prohibitions prescribed in the Central Coast Basin Plan.

(ii)

Discharges of material other than stormwater (which are not otherwise authorized by an NPDES permit) to a separate storm sewer system (MS4) or waters of the nation are prohibited, except as allowed in Subsection 23.05.044.f(v).

(iii)

Stormwater discharges shall not cause or threaten to cause pollution, contamination, or nuisance.

(iv)

Stormwater discharges regulated by the General Construction Permit shall not contain a hazardous substance equal to or in excess of a reportable quantity listed in Title 40 of the Code of Federal Regulations, Part 117 and/or Title 40 of the Code of Federal Regulations, Part 302.

(2)

Receiving water limitations.

(i)

Stormwater discharges and authorized non-stormwater discharges to any surface or ground water shall not adversely impact human health or the environment.

(ii)

The SWPPP developed for the construction activity shall be designed and implemented such that stormwater discharges and authorized non-stormwater discharges shall not cause or contribute to an exceedance of any applicable water quality standards contained in a Statewide Water Quality Control Plan and/or the Central Coast Regional Water Quality Control Board's Basin Plan.

(iii)

Should it be determined by the permit holder, County, State Water Resources Control Board (SWRCB), or Regional Water Quality Control Board (RWQCB) that stormwater discharges and/or authorized non-stormwater discharges are causing or contributing to an exceedance of an applicable water quality standard, the permit holder shall:

(a)

Implement corrective measures immediately following discovery that water quality standards were exceeded, followed by notification to the County and RWQCB by telephone as soon as possible but no later than 48 hours after the discharge has been discovered. This notification shall be followed by a report within 14-calendar days to the County and Central Coast Regional Water Quality Control Board, unless otherwise directed by the County and/or RWQCB, describing the following:

1.

the nature and cause of the water quality standard exceedance;

2.

the BMPs currently being implemented;

3.

any additional BMPs which will be implemented to prevent or reduce pollutants that are causing or contributing to the exceedance of water quality standards;

4.

any maintenance or repair of BMPs; and

5.

an implementation schedule for corrective actions that describes the actions taken to eliminate or reduce the pollutants causing or contributing to the exceedance.

(b)

Revise the SWPPP and monitoring program immediately after the report to the County and RWQCB to incorporate the additional BMPs that have been and will be implemented, the implementation schedule, and any additional monitoring needed.

(c)

Nothing in this section shall prevent the County and/or the Central Coast RWQCB from enforcing any stormwater discharge regulations while the permit holder prepares and implements the above report.

(3)

Anticipated noncompliance. The permit holder shall give advance notice to the County and RWQCB of any planned changes in the construction activity which may result in noncompliance with General Construction Permit or County Code requirements.

e.

Groundwater recharge standards. Groundwater recharge measures shall be required as part of any land use permit processed pursuant to Chapter 23.02. Plan contents and standards shall be as specified in Section 23.05.038 and as listed below. Stormwater impoundment areas shall:

(1)

Be located to use the most permeable soils on the project site, where practical.

(2)

Be sufficiently shallow or properly shielded so that they do not pose a safety hazard.

(3)

Drain fast enough or be designed so that ponded water does not become a vector habitat (mosquito pond).

f.

Pond, reservoir, and dam standards.

Note: All surface stream water impoundments require approval of an application to appropriate water from the California State Water Resources Control Board, Division of Water Rights.

(1)

Location. The proposed site of the pond, reservoir or dam shall not be:

(i)

Identified on any U.S. Geological Survey map as a lake, marsh, or solid or broken "blue line" stream unless the project has been reviewed subject to CEQA and determined not to contain significant adverse impacts to the aquatic or riparian resources.

(ii)

In a location identified on any published geologic or soils maps on soils prone to slip or slide.

(2)

Required reports. The Director, in granting a permit for construction, may require supporting geological and geotechnical engineering reports as deemed necessary for the safe design and construction of such facility. A report from a civil engineer certifying that construction of the facility has been completed in conformity with the approved plans and specifications and the Grading Ordinance may be required.

[Added 2013, Ord. 3253]

Editor's note

See editor's note, § 23.05.020.