Article III — DESIGN STANDARDS

Excavations shall be constructed or protected so that they do not endanger life or property.

(Code 1968, § 36.04.010)

The slope of cut surfaces of permanent excavations shall not be steeper than two (2) horizontal to one (1) vertical exclusive of terraces and exclusive of roundings described herein. Steeper slopes may be permitted in competent bedrock provided such slope inclinations are in accordance with recommendations contained in the geotechnical or geological report. The bedding planes or principal joint sets in any formation when dipping towards the cut face shall not be daylighted by the cut slope unless the soils and geologic investigations contain recommendations for steeper cut slopes. The Town Engineer may require the excavation to be made with a cut face flatter in slope than two (2) horizontal to one (1) vertical if necessary for stability and safety. Cut slopes shall be rounded into the existing terrain to produce a contoured transition from cut face to natural ground.

(Code 1968, § 36.04.015)

Fills shall be constructed in layers. The loose thickness of each layer of fill material before compaction shall not exceed eight (8) inches. Completed fills shall be stable masses of well integrated material bonded to adjacent materials and to the materials on which they rest. Fills shall be competent to support anticipated loads and be stable at the design slopes shown on the plans. Proper drainage and other appropriate measures shall be taken to ensure the continuing integrity of fills. Earth materials shall be used which have

no more than minor amounts of organic substances and have no rock or similar irreducible material with a maximum dimension greater than six (6) inches.

(Code 1968, § 36.04.020)

All fills shall be compacted throughout their full extent to a minimum of ninety (90) percent of maximum density as determined by appropriate ASTM standard method or other alternate methods approved by the Town Engineer. Tests to determine the density of compacted fills shall be made on the basis of not less than one (1) test for each two-foot vertical lift of the fill but not less than one (1) test for each one thousand (1,000) cubic yards of material placed. Additional density tests at a point approximately one-foot below the fill slope surface shall be made on the basis of not less than one (1) test for each one thousand (1,000) square feet in slope surface but not less than one (1) test for each ten-foot vertical increase of slope height. Additional tests may be required throughout the fill as determined by the inspector for the Town Engineer. All tests shall be reasonably uniformly distributed within the fill or fill slope surface. Results of such testing and location of tests shall be presented in the periodic and final reports. Compaction may be less than ninety (90) percent of maximum density, as determined by the above test, within six (6) inches of the slope surface when such surface material is placed and compacted by a method acceptable to the Town Engineer for the planting of the slopes. Compaction of temporary storage falls, to be used for a period of not greater than six (6) months, shall not be required, except where the Town Engineer determines that compaction is necessary as a safety measure to aid in preventing saturation, sliding, or erosion of the fill. Where compaction is required, it shall be done as specified by the Town Engineer.

(Code 1968, § 36.04.025)

The natural ground surface shall be prepared to receive fill by removing vegetation, noncomplying fill, top soil, and other unsuitable material, and where slopes are five (5) horizontal to one (1) vertical or steeper, by benching into competent material in a manner acceptable to the Town Engineer. The keyway under the toe, if specified, shall be at least ten (10) feet wide.

(Code 1968, § 36.04.030)

The slope of permanent fills shall not be steeper than two (2) horizontal to one (1) vertical exclusive of terraces and exclusive of rounding described herein. The Town Engineer may require that the fill be constructed with an exposed surface flatter than two (2) horizontal to one (1) vertical or may require such other measures as deemed necessary for stability and safety. Fill slopes shall be rounded into existing terrain to produce a contoured transition from fill face to natural ground or to abutting cut or fill surfaces where conditions permit.

(Code 1968, § 36.04.035)

Footings which may be affected by any excavation shall be underpinned or otherwise protected against settlement and shall be protected against lateral movement. Fills or other surcharge loads shall not be placed adjacent to any building or structure unless such building or structure is capable of withstanding the additional loads caused by such fill or surcharge. The rights of coterminous owners shall be as set forth in Civil Code section 832.

(Code 1968, § 36.04.040)

Unless otherwise recommended in a soil and geologic investigation report, Figure 70-1 on page 881 of the 1988 Uniform Building Code or similar provisions as provided for in an adopted successor code shall be used for establishing setbacks for property boundaries, buildings and structures other than fences and retaining walls.

(Code 1968, § 36.04.045)

The drainage structures and devices required by this chapter shall be designed and constructed in accordance with standards and criteria authorized by the Town Engineer.

(Code 1968, § 36.04.050)

All drainage facilities shall be designed to carry surface and subsurface waters to the nearest adequate street, storm drain, natural watercourse or other juncture, and shall be subject to the approval of the Town Engineer. Drainage areas shall conform to patterns established by the Town Engineer.

(Code 1968, § 36.04.055)

All areas shall be graded and drained so that the water will not pond or accumulate. Drainage shall be effected in such a manner that it will not cause erosion or endanger the stability of any cut or fill slope or any building or structure.

(Code 1968, § 36.04.060)

When surface drainage is discharged onto any adjoining property, it shall be discharged in such a manner that it will not cause erosion or endanger any cut or fill slope or any building or structure.

(Code 1968, § 36.04.065)

Terraces at least eight (8) feet in width shall be established at not more than twenty-five (25) feet in height intervals for all cut and fill slopes exceeding thirty (30) feet in height. Where only one (1) terrace is required, it shall be at approximately mid-height. Suitable access shall be provided to permit proper cleaning and maintenance of terraces and terrace drains. Swales or ditches on terraces shall have a minimum depth of one (1) foot, a minimum longitudinal grade of four (4) percent, a maximum longitudinal grade of twelve (12) percent, and must be paved with reinforced concrete not less than three (3) inches in thickness or an approved equivalent paving. Downdrains or drainage outlets shall be provided at approximately three hundred (300) foot intervals along the drainage terrace. Downdrains and drainage outlets shall be of approved materials and of adequate capacity to convey the intercepted waters to the point of disposal. If the drainage discharges onto natural ground, adequate erosion protection shall be provided.

(Code 1968, § 36.04.070)

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

(Code 1968, § 36.04.075)

The following shall apply to the control of erosion and sediment from grading operations:

(1)

Grading plans shall be designed with long-term erosion and sediment control as a primary consideration.

(2)

No grading operations shall be conducted during the rainy season except upon a clear demonstration, to the satisfaction of the Town Engineer, that at no stage of the work will there be any substantial risk of increased sediment discharge from the site.

(3)

Should grading be permitted during the rainy season, the smallest practicable area of erodible land shall be exposed at any one (1) time during grading operations and the time of exposure shall be minimized.

(4)

Natural features, including vegetation, terrain, watercourses and similar resources shall be preserved wherever possible. Limits of grading shall be clearly defined and marked to prevent damage by construction equipment.

(5)

Permanent vegetation and structures for erosion and sediment control shall be installed as soon as possible.

(6)

Adequate provision shall be made for long term maintenance of permanent erosion and sediment control structures and vegetation.

(7)

No top soil shall be removed from the site unless otherwise directed or approved by the Town Engineer. Top soil overburden shall be stockpiled and redistributed within the graded area after rough grading to provide a suitable base for seeding and planting. Runoff from the stockpiled area shall be controlled to prevent erosion and resultant sedimentation of receiving water.

(8)

Runoff shall not be discharged from the site in quantities or at velocities substantially above those which occurred before grading except into drainage facilities whose design has been specifically approved by the Town Engineer.

(9)

Permittee shall take reasonable precautions to ensure that vehicles do not track or spill earth materials into public streets and shall immediately remove such materials if this occurs.

(Code 1968, § 36.04.080)

Should increased sediment discharge occur or become imminent, permittee shall take all necessary steps to control such discharge. Such steps may include construction of additional facilities or removal or alteration of facilities required by approved erosion and sediment control plans. Facilities removed or altered shall be restored as soon as possible afterward or appropriate changes in the plan shall be immediately requested pursuant to this chapter. Permittee shall take prompt action to resolve emergency problems; otherwise the Town Engineer may suspend or revoke the permit.

(Code 1968, § 36.04.085)