Tehama Municipal Code Art. IV Grading Standards

The purpose of these standards is to safeguard life, limb, property, environmental health and water quality and the public welfare by regulating grading on private property.

(Ord. 1901 § 1(part), 2008)

As used in this article, and unless the context in which a word is used requires a different meaning, the following terms have the meanings indicated in this section:

A. "Approval" shall mean a written engineering or geological opinion concerning the progress and completion of the work.

B. "As graded" shall mean the surface conditions extent on completion of grading.

C. "Bedrock" shall mean in-place solid rock.

D. "Bench" shall mean a relatively level step excavated into earth material on which fill is to be placed.

E. "Borrow" shall mean earth material acquired from an off-site location for use in grading on a site.

F. "Civil engineer" shall mean a professional engineer registered in the State of California to practice in the field of civil works.

G. "Civil engineering" shall mean the application of the knowledge of the forces of nature, principles of mechanics and the properties of the materials to the evaluation, design and construction of civil works for the beneficial uses of mankind.

H. "Compaction" shall mean densification of a fill by mechanical means.

I. "Earth material" shall mean any soil, sand, gravel, decomposed granite, or other natural material or fill or any combination thereof.

J. "Engineered grading" shall mean grading in excess of five thousand cubic yards or in variance with the grading standards.

K. "Engineering geologist" shall mean a geologist experienced and knowledgeable in engineering geology.

L. "Engineering geology" shall mean the application of geologic knowledge and principles in the investigation and evaluation of naturally occurring rock and soil for use in the design of civil works.

M. "Engineering geology report" shall mean a report prepared by an engineering geologist that includes an adequate description of the geology of the site, conclusions and recommendations regarding the effect of geological conditions on the proposed development, and opinions and recommendations covering the adequacy of sites to be developed by the proposed grading.

N. "Erosion" shall mean the wearing away of the ground surface as a result of the movement of wind, water, ice or a combination thereof.

O. "Excavation" shall mean the mechanical removal of earth material.

P. "Fill" shall mean a deposit of earth material placed by artificial means.

Q. "Grade" shall mean the vertical location of the ground surface.

R. "Existing grade" shall mean the grade prior to grading.

S. "Rough grade" shall mean the stage at which the grade approximately conforms to the plan.

T. "Finish grade" shall mean the final grade of the site which conforms to the plan.

U. "Grading" shall mean any excavating or filling or combination thereof for which a grading permit is required.

V. "Key" shall mean a designed compacted fill placed in a trench excavated in earth material beneath the toe of a proposed fill slope.

W. "Site" shall mean any lot or parcel of land or contiguous combination thereof, under the same ownership, where grading is performed or permitted.

X. "Slope" shall mean an inclined ground surface, the inclination of which is expressed as a ratio of horizontal distance to vertical distance.

Y. "Soil" shall mean naturally occurring surficial deposits overlying bedrock.

Z. "Soil engineer" shall mean a civil engineer experienced and knowledgeable in the practice of soil engineering.

AA. "Soil engineering" shall mean the application of the principles of soil mechanics in the investigation, evaluation and design of civil works involving the use of earth materials and the inspection and testing of the construction thereof.

BB. "Soil engineering report" shall mean a report prepared by a soil engineer that includes data regarding the nature, distribution and strength of existing soils, conclusions and recommendations for grading procedures and design criteria for corrective measures when necessary, and opinions and recommendations covering adequacy of sites to be developed by the proposed grading.

CC. "Terrace" shall mean a relatively level step constructed in the face of a graded slope surface for drainage and maintenance purposes.

DD. "Vertical height" shall mean the vertical distance between the toe of a slope and a line level with the top of that slope.

(Ord. 1901 § 1(part), 2008)

A. General. Unless otherwise recommended in a soil engineering and/or engineering geology report, cuts shall conform to the provisions of this section.

B. Slope. The slope of cut surfaces shall be no steeper than is safe for the intended use. Cut slopes shall be no steeper than two horizontal to one vertical unless a soil engineering report is submitted and approved by the enforcing officer substantiating the need for a steeper cut slope, and a discretionary grading permit is obtained in accordance with this chapter.

C. Drainage and Terracing. Drainage and terracing shall be provided as required by Section 9.43.320.

(Ord. 1901 § 1(part), 2008)

A. General. Unless otherwise recommended in an approved soil engineering report, fills shall conform to the provisions of this subsection.

B. Fill Location. Fill slopes shall not be constructed on natural slopes steeper than two to one. Fill slopes in excess of thirty percent shall be constructed under the direction of a soil engineer.

C. Preparation of Ground. The ground surface shall be prepared to receive fill by removing vegetation, non-complying fill, topsoil and other unsuitable materials and scarifying to provide a bond with the new fill, and where slopes are steeper than five to one, and the height is greater than five feet, by benching into sound bedrock or other competent material. The bench under the toe of a fill on a slope steeper than five to one shall be at least ten feet wide. The area beyond the toe of fill shall be sloped for sheet overflow or a paved drain shall be provided. Where fill is to be placed over a cut, the bench under the toe of fill shall be at least ten feet wide but the cut must be made before placing fill.

D. Compaction. All fills shall be compacted to a minimum of ninety percent of maximum density. Compaction tests shall be conducted by a California registered civil engineering or geotechnical engineering company, or by an approved materials testing laboratory. Compaction tests shall be done in compliance with California test methods 216 and 231.

E. Slope. The slope of fill surfaces shall be no steeper than is safe for the intended use.

F. Drainage and Terracing. Drainage and terracing shall be provided and the area above fill slopes and the surfaces of terraces shall be graded and paved as required by Section 9.43.320.

(Ord. 1901 § 1(part), 2008)

A. General. The setbacks and other restrictions are minimum and may be increased by the recommendation of a civil engineer, soils engineer or engineering geologist, if necessary for safety and stability or to prevent damage of adjacent properties from deposition or erosion or to provide access for slope maintenance and drainage. Retaining walls may be used to reduce the required setbacks.

B. Setbacks from Property Lines. The tops of cuts and toes of fill slopes shall be set back from the outer boundaries of the property line, including slope areas and easements, in accordance with the Tehama County Land Development Standards.

C. Design Standards for Setbacks. Setbacks between graded areas (cut or fill) and structures shall be provided in accordance with the Tehama County Land Development Standards.

(Ord. 1901 § 1(part), 2008)

A. General. Unless otherwise indicated on a grading plan prepared pursuant to Section 9.43.340, drainage facilities and terracing shall conform to the provision of this section.

B. Terrace. Terraces at least six feet in width shall be established at not more than thirty-foot vertical intervals on all cut or fill slopes to control surface drainage and debris except that where only one terrace is required, it shall be at mid-height. For cut or fill slopes greater than sixty feet and up to one hundred twenty feet in vertical height one terrace at approximately mid-height shall be twelve feet in width. Terrace widths and spacing for cut and fill slopes greater than one hundred twenty feet in height shall be designed by a civil engineer. Suitable access shall be provided to permit proper cleaning and maintenance.

Swales or ditches on terraces shall have a minimum gradient of five percent and must be paved with reinforced concrete not less than three inches in thickness or an approved equal paving or rock and fabric lining. They shall have a minimum depth at the deepest point of one foot and a minimum paved width of five feet.

A single run of swale or ditch shall not collect runoff from a tributary area exceeding thirteen thousand five hundred square feet (projected) without discharging into a downdrain.

C. Subsurface Drainage. Cut and fill slopes shall be provided with subsurface drainage as necessary for stability.

D. Disposal. All drainage facilities shall be designed to carry waters to the nearest practicable drainage way or other appropriate jurisdiction as a safe place to deposit such waters. Erosion of ground in the area of discharge shall be prevented by installation of non-erosive downdrains or other devices.

Building pads shall have a drainage gradient of two percent toward approved drainage facilities, provided that the gradient from the building pad may be one percent if all of the following conditions exist throughout the permit area:

1. No proposed fills are greater than ten feet in maximum depth; and

2. No proposed finish cut or fill slope faces have a vertical height in excess of ten feet; and

3. No existing slope faces, which have a slope face steeper than ten horizontally to one vertically, have a vertical height in excess of ten feet.

E. Interceptor Drains. Paved interceptor drains or properly designed rock channels lined with fabric shall be installed along the top of all cut slopes where the tributary drainage area above slopes towards the cut and has a drainage path greater than forty feet measured horizontally. Interceptor drains shall be paved with a minimum of three inches of concrete or gunite and reinforced. They shall have a minimum depth of twelve inches and a minimum paved width of thirty inches measured horizontally across the drain. Rock and fabric lined channels shall be designed by a soil engineer and must withstand the maximum potential flow and retain its integrity.

(Ord. 1901 § 1(part), 2008)

When construction activities propose to disturb areas of existing vegetation and ground cover by grading, effective erosion and sediment control measures shall be employed.

A. Erosion Control Plan. Whenever a grading permit requires an erosion control plan, it shall be submitted with the grading plan as per stipulations in the grading permit.

If the site or portion of the site is planned to be idle for more than forty-five days, then vegetative stabilization must be accomplished within seven days. The wet weather plan shall include a plan for the immediate (within twenty-four hours of the first forecast of a storm front) installation of emergency erosion control measures.

B. Design Standards. Best management practices shall be employed.

(Ord. 1901 § 1(part), 2008)

All engineered grading requires a grading plan prepared by a civil engineer prior to commencement of work.

The civil engineer who prepares a grading plan shall incorporate all recommendations from the soil engineering report and any engineering geology report into the grading plan. He shall also be responsible for the professional inspection and approval of the grading within his area of technical specialty. This responsibility shall include, at a minimum, grade and drainage of the development area.

A soil engineering report shall be prepared for each grading plan prepared by a civil engineer.

The soil engineer's area of responsibility shall include, at a minimum, the professional inspection and approval concerning the preparation of ground to receive fills, testing for required compaction, stability of all finish slopes and the design of buttress fills, where required, incorporating any data supplied by an engineering geologist.

If an engineering geologist is retained for the work, his area of responsibility shall include, at a minimum, professional inspection and approval of the adequacy of natural ground for receiving fills and the stability of cut slopes with respect to geological matters, and the need for subdrains or other ground water drainage devices. He shall report his findings to the soil engineer and the civil engineer for engineering analysis. If an engineering geologist is not retained, the civil engineer who prepares the grading plan shall assume the responsibilities of the engineering geologist.

(Ord. 1901 § 1(part), 2008)

If, in the course of development, any archeological or cultural remains are encountered, work shall cease and a qualified archeologist contacted immediately. If any potential prehistoric, protohistoric, and historic cultural resources are encountered during any phase of the project operations, all work should cease in the area of the find pending examination of the site and materials by a qualified archaeologist.

(Ord. 1901 § 1(part), 2008)