Paso Robles Municipal Code Ch. 20.16 Grading Requirements

A. Availability of Permit at Site. No person shall perform any grading for which a permit is required under this title unless a copy of the grading permit is in the possession of a responsible person and available at the site.

B. Nuisance or Hazardous Conditions. Whenever the director of public works determines that a severe nuisance condition has been created from blowing dust, sloughed or spilled dirt, uncontrolled drainage and siltation, or that any excavation, embankment or fill has become a hazard to life and limb, or endangers structures, or adversely affects the safety, use, or stability of a public way or drainage channel, the owner of the property upon which the excavation, embankment, or fill is located, or other person or agent in control of the property, upon receipt of notice in writing from the director of public works shall within the period specified therein repair, reconstruct or remove such excavation, embankment, or fill so as to eliminate the nuisance or hazard. If necessary, all site work shall be halted as directed until the corrective work has been satisfactorily completed.

C. Supervision. The permittee shall provide sufficient supervisory control during the grading operations to insure compliance with the approved plans and with the provisions of this chapter. The permittee shall avail himself of geologic and/or soils engineering services to implement the supervisory control of the permittee's registered civil engineer. The engineering geologist and/or soils engineer shall be properly qualified to perform such services within the city. Periodic reports as required by the city engineer shall be submitted by the soils engineer and/or engineering geologist.

D. Safety Precautions During Grading. If, at any stage of work on an excavation or fill, the city engineer determines by inspection that further work as authorized by an existing permit is likely to endanger any property or public way, the city engineer may require the plans for such affected area be amended to include adequate safety precautions as a condition to allow the work to continue. The city engineer may cause the work on the affected area to be halted and may require that plans be amended to include adequate safety precautions as a condition to allow the work to continue.

E. Supervised Grading.

1. Where necessary, the city engineer shall require the permittee to employ:

a. A registered civil engineer to observe construction to determine substantial conformance to the approved plans;

b. A soils engineer to provide either constant or continuous soils inspections and testing; or

c. An engineering geologist to provide either constant or continuous geological inspections as needed on job.

2. The employment of such persons shall not be deemed to render unnecessary inspections described in this chapter except that on any work requiring the continuous observation and inspection of a registered civil engineer, the inspections required by this section may be delegated to the registered civil engineer by the city engineer.

3. If the registered civil engineer, soils engineer, or engineering geologist, fulfilling his responsibility pursuant to the provisions of this section, finds that work is not being done in conformance with the provisions of this title or the plans and specifications approved by the city engineer, the registered civil engineer, soils engineer, or engineering geologist shall immediately notify the person in charge of the grading work, and if the nonconformity is not corrected, the city engineer shall be notified in writing of the nonconformity and of the corrective measures to be taken.

4. If for any reason, the services of any of the professional persons are terminated during the progress of the grading work, such professional person and the permittee shall immediately notify the city engineer in writing. Such termination may result in temporary delays in the grading operations until satisfactory arrangements are made to assure the city engineer that competent professional supervision is provided. When the services of any of the professionals of record are terminated, the professional whose services have been terminated shall submit to the city engineer certification of work performed under his supervision, along with deficiencies to be corrected. The new professional shall submit to the city engineer a letter of certification that the previous professional's design, reports, and recommendations have been reviewed, that the conditions city engineer required as conditions of the grading permit will be complied with during the course of the work, and that he shall review the detailed grading plans and thus assume his responsibility as set forth in this chapter for all future grading on the project.

5. The certification shall state that the job was constructed as indicated by the "as-built" plan, that the soils engineer and engineering geologist's reports and certifications have been submitted, that they have provided their services in accordance with good practices, and that all drainage provisions and safety features have been incorporated in the grading of the site.

F. Hillside Grading.

1. The rules and regulations set forth in this subsection shall apply to all hillside area grading in the city which shall be considered supervised grading.

2. The permittee shall employ a registered civil engineer to prepare the design of grading plans for all hillside grading. The design civil engineer shall prepare his design in accordance with good planning practices and applicable codes and to the restrictions imposed as determined by detailed studies of the site and materials to be graded. Such studies shall be performed by a soils engineer, and if required, an engineering geologist approved by the city engineer and shall be submitted prior to the issuance of permits. The civil engineer shall furnish sufficient observation during construction to obtain compliance with the plans as approved.

3. The permittee shall employ a soils engineer whose duties shall be to work closely with the civil engineer, to examine surface and subsurface conditions and to submit reports thereon. Such reports, in conjunction with the provisions of this chapter, shall form the basis for the design of the grading project. Such reports shall be based upon a detailed topographic base map of the area to be graded and shall include specific conclusions and recommendations for avoidance or correction of all known existing or anticipated geologic hazards and adverse soil conditions on or affecting the site or contiguous property.

4. The soils engineer, in addition to his pre-grading exploratory work, shall provide inspections during the placement of all compacted fill in accordance with the requirements of this chapter, the approved plans and good engineering practices. In addition, he shall follow the progress of the job sufficiently close to determine that the recommendations of his pre-grading report are followed. If conditions which require the modification of plans are encountered during grading, he shall submit a report of his findings and recommendations for a change of plans to the permittee and the civil engineer, the engineering geologist, and the city engineer.

(Ord. 702 N.S. (part), 1995; Ord. No. 994 N.S., § 4, 8-20-2013)

A. Vegetation. Areas not directly involved in grading operations shall remain undisturbed in order to preserve the natural vegetation and to reduce the potential for dust or erosion. Oak trees are a protected species within the city, and all work in the vicinity of any Oak trees shall be done in accordance with Chapter 10.01, Oak Tree Preservation.

B. Topsoil. Within the areas to be graded, the topsoil shall be stripped and stockpiled for later use at the sites. Upon completion of the rough grading, the topsoil shall be spread as directed over the slopes to promote the establishment of reseeding or landscaping.

(Ord. 702 N.S. (part), 1995; Ord. No. 994 N.S., § 4, 8-20-2013)

In the interest of preserving and blending with the natural land forms, the final graded slopes shall be rounded and contoured so as to avoid abrupt grade-breaks and sharp edges where desirable and as directed. Long linear slopes are to be avoided.

(Ord. 702 N.S. (part), 1995; Ord. No. 994 N.S., § 4, 8-20-2013)

A. Height. Cut slopes shall not exceed a vertical height of twenty-five feet unless approved by the planning commission. If a cut slope is permitted above such height, a horizontal bench with a minimum width of six feet shall be required to be installed at each fifteen feet of vertical height. Additional grading restrictions may be required in accordance to the zoning regulations of the city's Municipal Code.

B. Slope. Excavations shall not be made with a cut face steeper in slope than is safe and shall be no steeper than two horizontal to one vertical.

Exception. The city may permit the excavation to be made with a cut face in slope one and one-half horizontal to one vertical if the applicant shows through subsurface exploration, by both a soils engineer and an engineering geologist, to the satisfaction of the city engineer, that the material making the slope of the excavation and the underlying material is capable of permanent stability on a steeper slope.

C. Unstable Material. If the material of the slope is of such composition and character as to be unstable, considering all types of anticipated loading and moisture conditions, the engineering geologist and soils engineer shall, by testing and analysis, provide specific criteria for the stabilization of such material by the reduction of the slope angle, by buttressing, or by a combination of these or other means.

D. Bedding Planes. No slope shall be cut steeper than the bedding planes or adverse components of dips. Where the excavation exposes strata above the top of the cut which will permit the entry of water along bedding planes, such area shall be sealed with a compacted soil blanket of low permeability having a minimum thickness of two feet. The soil for such blanket shall be relatively impervious and shall be tested and approved by the soils engineer.

E. Cut Slope Limits. Tops of cut slopes shall not be made nearer than two feet plus one-fifth of the height of the cut to the project boundary but need not exceed a horizontal distance of ten feet. Cut slopes shall not be divided horizontally by property lines, and cut slopes occurring on a side or rear lot line shall be made a part of the downhill lot. If the city engineer determines that such requirement is unnecessary because of special conditions, he may make adjustments as a condition of the grading permit.

F. Intervening Terraces. Terraces on cut slopes, shall have a minimum width of six feet, shall be extensively landscaped in accordance with an approved landscaping plan, and shall be spaced at intervals of fifteen feet measured vertically. Where only one terrace is utilized, it shall be placed at approximate mid-height. Where soil conditions warrant, additional intervening terraces may be required.

G. Temporary Excavations and Shoring. Excavations shall not remove the lateral support from a public way or from an existing structure. For the purposes of this section, the lateral support shall be considered to have been removed when any of the following conditions exist:

1. The excavation exposes any adverse geological formations which would affect the lateral support of a public way or of an adjacent structure;

2. The excavation extends below a plane extending downward at an angle of forty-five degrees from the edge of the public way.

Exception. Normal footing excavations not exceeding two feet in depth shall not be construed as removing lateral support.

3. The excavation extends below a plane extending downward at an angle of forty-five degrees from the bottom of a footing of an existing structure.

(Ord. 702 N.S. (part), 1995; Ord. No. 994 N.S., § 4, 8-20-2013)

A. Height. No finished fill slope shall exceed a vertical height of twenty-five feet unless approved by the planning commission. Additional grading restrictions may be required in accordance to the zoning regulations of the city's Municipal Code.

B. Slope. The slope of fill surfaces shall be no steeper than is safe. No fill shall be made which creates any exposed surface steeper in slope than two horizontal to one vertical.

C. Unstable Material. The city engineer may require that the fill be constructed with an exposed surface flatter than two horizontal to one vertical if, under the particular conditions, such flatter surface is necessary for stability or safety.

D. Fill Slope Limits. Toes of fill slopes shall not be made nearer to a project boundary line than two feet plus one-half of the height of the fill, but need not exceed a horizontal distance of twenty feet. Fill slopes shall not be divided horizontally by property lines, and fill slopes occurring on a side or rear lot line shall be made a part of the downhill lot. If the city engineer determines such requirement is unnecessary because of special conditions, he or she may make adjustments as a condition of the grading permit.

E. Intervening Terraces.

1. Terraces shall have a minimum width of six feet, shall be extensively landscaped in accordance with an approved landscaping plan, and shall be spaced at vertical intervals of fifteen feet; where only one terrace is utilized it shall be placed at approximately mid-height. Where soil conditions warrant, additional intervening terraces may be required.

2. Suitable access shall be provided to permit proper cleaning and maintenance.

Exception. The city engineer may waive the requirements for terraces where a soils engineering or engineering geology report indicates the requirements are not necessary to carry out the purpose and intent of this chapter.

F. Compaction. All fills shall be placed, compacted, inspected, and tested in accordance with the provisions of this subsection. If the strict enforcement of the provisions of this subsection is determined by the city engineer to be unnecessary because of the proposed or probable use of the land, he or she may waive the requirements. The requirements of this subsection shall not be waived when structures are to be supported by the fill, or if the fills are being placed in areas to be designated as hillside, or where they are necessary as a safety measure to aid in preventing the saturation, settling, slipping, or erosion of the fill.

1. The natural ground surface shall be prepared to receive fill by removing vegetation, noncomplying fill, top soil, and/or porous, compressible soil. Where natural slopes are five horizontal to one vertical or steeper, the height of the fill is twenty feet or greater, benching into sound bedrock or other competent material, by placing at least ten-foot wide keys and benches, shall be required. Fill slopes which toe on natural slopes shall be provided with adequate drainage.

2. No deleterious material shall be permitted in fills. Except as otherwise permitted by the city engineer, no rock or similar irreducible material with a maximum dimension greater than six inches shall be buried or placed in fills.

Upon recommendations made by a soils engineer and approved by the city engineer prior to the grading of any project, rock with dimensions from twelve inches to thirty-six inches may be placed in compacted fill. Such oversized rocks shall not be in the upper ten feet of compacted fill or nearer than twenty feet to the surface of any fill slope. Such rock areas shall be shown on record drawing plans and certified by the soils engineer to be compacted or placed so as not to create a structural support problem.

3. The fill shall be spread in a series of layers, each not exceeding six inches in thickness, and shall be compacted by an approved method after each layer is spread.

4. The moisture content of the fill material shall be controlled at the time of spreading and compacting to obtain the required relative compaction and avoid excessive pore pressure as the fill increases in depth.

5. All fills shall be compacted to a minimum of ninety percent of the maximum density as determined by A.S.T.M. D 1557-66T, Method A or C, modified to three layers. If the required degree of relative compaction cannot be attained on sloped surfaces, the slope shall be cut back until the compacted inner core is exposed.

The field density shall be measured in accordance with the procedure specified in A.S.T.M. D 1556-58T, or later revision, using the optional base plate and making a suitable adjustment for volumes of rocks in the test hole or other approved testing methods giving equivalent test results.

6. A field density test, as set forth in subsection (F)(5) of this section, shall be taken for each two feet of fill, or portion thereof, measured vertically from the lowest point of the area to be filled, or for each one thousand cubic yards of fill placed. In addition, in the case of subdivisions, at least one field density test shall be taken on each lot which receives fill.

7. All fills regulated by the provisions of this chapter shall be tested for relative compaction by the soils engineer. A certificate of compliance with the terms of this section and the grading permit, setting forth densities, relative compaction, the expansive soil report, allowable bearing value, and other soil characteristics, shall be prepared and signed by the soils engineer. Such report shall be submitted to, land be approved by, the city engineer before any final approval of the fill is given and before any foundation construction begins.

8. Fills in non-hillside areas which do not exceed twelve inches in depth need not be compacted, but such fills shall not change the existing drainage pattern of the area.

9. Subdrains. In hillside areas, subdrains shall be constructed under all fills placed in natural watercourses as required by the soils engineer. Typically, subdrains shall be placed along the watercourse flow line and along the flow line of any branches tributary thereto. Additional subdrains may be installed to collect all active or potential springs or seeps which will be covered by the fill. Subdrains when required shall be installed after the watercourse has been excavated to unyielding natural soil in preparation for receiving the fill.

a. The actual design and location of subdrains shall be based on the recommendations of the soils engineer and engineering geologist and subject to the approval of the city engineer.

G. Fills Toeing Out on Natural Slope. Fills toeing out on natural slopes which are steeper than two horizontal to one vertical shall not be permitted.

H. Combined Cut and Fill Slopes.

1. Where a combined cut and fill slope exceeds twenty-five feet in height, a drainage bench shall be placed at the top of the cut slope. The effect of surcharge of the fill upon the underlying soil shall be considered by the soils engineer and engineering geologist, and specific recommendations shall be made relative to the setback between the cut and fill.

2. Fill placed on or above the top of an existing or proposed cut or natural slope steeper than three horizontal to one vertical shall be set back from the top of the slope a minimum distance of six feet.

I. Existing Fills. All existing man-made fills on any and all sites shall be properly evaluated, and if deficiencies exist, recommendations and design criteria for corrective measures shall be included within the soils engineering report.

J. Progress Reports.

1. Periodic soils reports by a soils engineer certifying the compaction or acceptability of all fills may be required. Such reports shall include, but need not be limited to, the inspection of cleared areas and benches prepared to receive fill and the removal of all soil and unsuitable materials, the bearing capacity of the fill to support structures, the placement and compaction of fill materials, and the inspection of buttress fills, subdrains, and similar devices. The frequency of such reports shall be at the discretion of the city engineer and shall be a condition of the grading permit.

2. The city engineer may require sufficient inspections by an engineering geologist to insure that all geologic conditions have been adequately considered. Where geologic conditions warrant, the city engineer may require periodic geologic reports. Such inspections and reports may be required to include, but need not be limited to, the inspection of cut slopes, canyons during clearing, operations for groundwater and earth material conditions, benches or keys prior to the placement of fill, and possible underground water spring locations.

K. Measure of Settlement. On fills of forty feet or more, if recommended by the soils engineer, the city engineer may require the determination of the settlement characteristics of such fills to establish that any movements have substantially ceased.

(Ord. 702 N.S. (part), 1995; Ord. No. 994 N.S., § 4, 8-20-2013)