Section 20.30.070 Minimum standards and safety precautions.

A grading permit may be issued to remain in force for up to twelve months. A grading permit may be renewed for additional twelve-month periods upon compliance with the following requirements:

1. The faces of cut and fill slopes shall be prepared and maintained to control soil erosion. Where necessary, vegetative plantings, check dams, cribbing, riprap or other devices or methods shall be employed to control erosion and provide safety.

2. All drainage provisions shall be designed to carry surface waters to the nearest practical storm drain, natural water course, or street approved by the city engineering division as a suitable place to deposit and receive such waters.

a. Cut and fill slopes shall be set back from site boundaries in accordance with this section. Setback dimensions shall be horizontal distances measured perpendicular to the site boundary.

b. The setback from a site boundary line for the top of a cut section or the toe of a fill section which does not involve a professionally designed retaining wall structure shall be the determined as follows: B = H ( 1 – S/4 ) , where B is the setback required, H is the height of the cut or fill section and S is the horizontal element of the slope ratio (e.g. S = 4 for a 4:1 slope). The setback shall not be less than 5 feet.

c. The setback for a retaining wall structure designed by a registered professional engineer, architect or landscape architect shall be sufficient to contain any of the structure of the retaining wall and to assure the adjoining property owner will not be deprived of rights to build

d. The setback may be reduced to zero if a recorded easement on the adjoining property for construction and maintenance of the cut or fill section equal in width to the reduction of the setback required by the provisions of subsection b. or c. above is secured.

e. The minimum setback may be increased as a result of a determination by the city engineering division that it is necessary to support a load on adjacent properties or that special site conditions warrant increased setbacks.

f. Where a cut or fill slope is to be located near the site boundary, special precautions shall be incorporated in the work as the city engineering division deems necessary to protect the adjoining property from damage. These precautions may include but are not limited to:

g. The city engineering division may require or approve alternate setbacks. The division may require an investigation and recommendation by a registered professional engineer experienced in soil mechanics or an engineering geologist to demonstrate that the intent of this section has been satisfied.

4. No grading shall allow earthen materials to be deposited upon, or to roll, flow or wash upon or over the premises of another without the explicit written consent of the owner of such premises so affected, or upon or over any public street, walk, place or way; nor so close to the top of a bank of a channel as to create the possibility of bank failure and sliding.

5. No cut or fill materials shall be transported to or from a site in such a manner as to permit it to be deposited upon any public street. In the event cut or fill material is deposited or tracked upon the public streets, the permit holder shall clean it up by the end of each working day or the City may clean it up and assess the costs of the cleanup.

6. Fill material shall be obtained from approved sources which shall be free of vegetative matter and deleterious material such as broken concrete, asphalt and large rocks unless specifically included in the specifications of the approved grading plan.

a. Excavations and fills should have a finished slope of three horizontal to one vertical; however, steeper excavations and fills may be made in extreme cases were a 3:1 slope is impossible to achieve and subject to the approval of the City Engineer and the following design certifications:

(1) An excavation or fill steeper than a 3:1 slope, but not steeper than 1:1 slope, that is less than 20 feet in height must be based upon a design prepared and certified by an architect, landscape architect, or professional engineer, registered in the state of Iowa.

(2) An excavation or fill steeper than a 3:1 slope that is more than 20 feet in height or which has a slope greater than 1:1 must be based upon a design prepared and certified by a registered professional engineer experienced in soil mechanics with substantiation by a soils investigative report.

c. The top of the cut or fill or any terrace created shall be shaped in such a manner that no surface water is allowed to flow over the edge. The top surface shall be stabilized by vegetation or other non-erodible surface.

a. For areas not covered by the provisions of (1), (2) or (3) below, the minimum soil compaction shall be 90% standard proctor (the maximum theoretical density using ASTM D-698).

(1) For fill associated with building construction projects for which the building official requires a design certified by a professional architect or engineer, the minimum soil compaction shall be specified by said design professional.

(2) For fill associated with grading in subdivisions or planned developments approved pursuant to Titles 24 or 25 of the Municipal Code, the minimum soil compaction shall be specified by the professional engineer who certifies the grading plan for said subdivision or planned development. The specified minimum soil compaction within a current or proposed public right-of-way or easement shall comply with the applicable requirements of the Sioux City Standard Specifications for Public Improvements.

(3) For fill that is placed on a site with on plan for how the site is to be used, the minimum soil compaction shall be 85% standard proctor, provided the owner of the site and the grading permit holder acknowledge in writing that the site of the fill is not appropriate for any construction unless soil testing confirms the bearing capacity of the soils at the time of application for a building permit.

b. Grading Tolerance: Areas to be graded by cutting or filling shall be rough graded to within ½ foot of accepted elevation after allowance has been made for thickness of top soil, paved areas and other installations.

c. Preparation of the natural ground surface by removing topsoil and vegetation and by compacting the fill upon a series of terraces or benches. Hillside or slope fills shall require scarification of terraces in the original ground after it has been divested of vegetation and rubbish.

e. Limitation on the use of various kinds of materials. Frozen materials or soft, mucky, friable, easily compressible materials shall not be incorporated in fills intended to support buildings, structures, sewers or conduits, or in the embanked ends of fills. Fill material shall not be placed, spread, or rolled while the ground is frozen or thawing.

f. Maximum thickness of layers of the fill to be compacted shall not exceed 8 inches unless an architect, landscape architect, or professional engineer, registered in the state of Iowa, specifies a higher maximum thickness of the layers of fill and methods to achieve the required compaction. The equipment and methods used shall be consistent with the type and condition of the material to be compacted.
9. Timber, logs, trees, tree stumps, brush, vegetable matter, masonry and rubbish of any description shall be removed and disposed of so as to leave the disturbed area with a neat and finished appearance. Solid rock, shale or similar materials shall be removed to a depth of 15 inches below subgrade for paved areas and 2 feet below finish grade for lawn areas except where it is impractical because of rock out-cropping.

10. Ground cover shall be established within 30 days after a phase of grading work is completed or by April 1 of the next year if completion is after October 1 in order to prevent erosion of finished grading. Such ground cover must be maintained in such a manner as to assure the long-term stability of the grading

a. A fill addendum shall be filed in the office of the County Recorder if current grading activity or if known grading activity within ten years prior to the current grading includes placement of fill material in excess of five feet in depth any where on the site of the grading.

b. The fill addendum shall be in the form of a duplicate of the site grading plan upon which has been indicated in a clearly interpretable pattern or other lines and annotations, the fill information needed by subsequent owners of the land.

d. The fill addendum shall include a certificate of a registered professional engineer who designed or supervised the grading project indicating the characteristics of the fill or the results of professionally competent soil testing. (Ord. 2006-0146; 2000-9159; 88/T-6762)