Conditions of permit

The requirements of subsections (a), (b), and (c) may be modified by the director of planning and permitting based on the engineer’s soils report and engineering slope hazard report. (a) Height. Where a cut or fill is greater than 15 feet in height, terraces or benches shall be constructed at vertical intervals of 15 feet, except that where only one bench is required, it shall be at the midpoint. The minimum width of such terraces or benches shall be at least 8 feet and provided with drainage provisions to control erosion on the slope face and bench surface. (b) Cut slopes. Under the following soil conditions, no cut may be steeper in slope than the ratio of its horizontal to its vertical distance as shown below: (1) One-half horizontal to one vertical in unweathered rock or mudrock; (2) One horizontal to one vertical in decomposed rock; and (3) One and one-half horizontal to one vertical in soils of low plasticity, cuts of any height in highly plastic soils shall be as recommended in the applicable report. (c) Fill slopes. Fills shall not be steeper than a ratio of two horizontal to one vertical, except that fill using highly plastic clays shall have slopes as recommended in the applicable report. (d) Distance from property line. The horizontal distance from the top of a cut slope or the bottom of a fill slope to the adjoining property line shall not be less than as follows: Height of Cut or Fill Distance from Property Line (in feet) Zero feet to 4 feet 2 More than 4 feet to 8 feet 4 More than 8 feet to 15 feet 6 More than 15 feet 8 These requirements may be modified by the director of planning and permitting when cuts or fills are supported by retaining walls or when the permittee submits an engineer’s soils report or engineering slope hazard report stating that the soil conditions will permit a lesser horizontal distance without causing damage or danger to the adjoining property. (e) Area opened. The maximum-sized parcel of land that may be opened for grading or grubbing is 15 acres. Noncontiguous increments may be worked concurrently provided no single parcel exceeds 15 acres, provided the work is in conformance with the NPDES permit. The area of land that may be opened may be reduced by the director of planning and permitting to control pollution and minimize storm damage. However, if soils, hydrologic, climatic and construction conditions warrant, and adequate erosion prevention measures have been taken, the director of planning and permitting may authorize additional area to be opened. Additional area may not be opened for grading or grubbing until measures to prevent dust or erosion problems in the area already graded or grubbed have been undertaken to the satisfaction of the director. (f) Fills. The requirements of subdivisions (1), (2), and (3) may be modified by the director of planning and permitting if the permittee submits an engineer’s soils report recommending criteria for the proposed fill for its intended use. (1) Fill material shall be selected to meet the requirements and conditions of the particular fill for which it is to be used. The fill material shall not contain vegetation or organic matter. Where rocks, concrete, or similar materials of greater than 8 inches in diameter are incorporated into the fill, they shall be placed in accordance with the recommendation of a soils engineer. (2) Preparation of ground surface. Before placing or stockpiling, the natural ground surface shall be prepared by removing the vegetation and, if required by the director of planning and permitting, shall be notched by a series of benches or subsurface drains, or both, installed. No fill shall be placed over any water spring, marsh, refuse dump, nor upon a soft, soggy, or springy foundation; provided that this requirement may be waived by the director of planning and permitting if the permittee submits an engineer’s soils report recommending criteria for the fill. (3) Placement and compaction. Fill materials shall be spread and compacted in a series of 8-inch to 10-inch layers when compacted, unless otherwise recommended by the soils engineer. Except for slopes, the fill shall be compacted to 90 percent of maximum density as determined by the most recent ASTM soil compaction test D1557 unless the engineer’s soils report justifies a lesser degree of compaction, or unless otherwise recommended by the soils engineer. (g) Vegetation. Whenever feasible, natural vegetation should be retained by becoming part of the erosion control plan during construction or part of the permanent landscaping plan, if applicable. If it is necessary that vegetation be removed, trees, timber, plants, shrubbery, and other woody vegetation, after being uprooted, displaced, or dislodged from the ground by excavation, clearing, or grubbing, shall not be stored or deposited along the banks of any stream, river, or natural watercourse. After being uprooted, displaced, or dislodged, such vegetation shall be disposed of by means approved in writing by the director of planning and permitting or removed from the site within a reasonable time, but not to exceed three months. (h) Drainage provisions. Adequate provisions shall be made to prevent surface waters from damaging the cut face of an excavation or the sloped surfaces of a fill. Positive drainage shall be provided to prevent the accumulation or retention of surface water in pits, gullies, holes or similar depressions. All drainage facilities shall be designed to carry surface waters to a street, storm drain inlet, or natural watercourse and shall include an erosion and sedimentation control plan to prevent sediment-laden runoff from leaving the site, either during or following construction. The director of planning and permitting may require such detention or retention drainage structures and pipes to be constructed or installed, which in the director’s opinion, are necessary to prevent erosion damage, prevent sediment-laden runoff from leaving the site, and to satisfactorily carry off surface waters. The flow of any existing and known natural underground drainage shall not be impeded or changed so as to cause damage to adjoining property. (i) Debris prohibited. No person shall perform any grading operation so as to cause falling rocks, soil, or debris in any form to fall, slide, or flow onto adjoining properties, streets, or natural watercourses. (j) Work days. No grading work may be done on Saturdays, Sundays, and holidays at any time without prior notice to the director of planning and permitting; provided that the grading work is also in conformance with Hawaii Administrative Rules Chapter 11-46, “Community Noise Control.” (k) Dust control. All work areas within and without the actual grading area must be maintained free from dust that will cause a nuisance or hazard to others and in conformance with the air pollution control standards contained in Hawaii Administrative Rules Chapter 11-60.1, “Air Pollution Control.” (l) Water quality standards. All grading operations authorized under this chapter shall be performed in conformance with the water pollution control and water quality standards contained in Hawaii Administrative Rules Chapter 11-55, “Water Pollution Control” and Chapter 11-54, “Water Quality Standards” and if applicable, the NPDES permit for the project. Any dewatering discharge into State waters will require an NPDES permit from the State department of health under Chapter 11-55, “Water Pollution Control”. Any dewatering discharge into the city-owned storm sewer system will require a construction dewatering permit from the director of planning and permitting and an NPDES permit for the discharge of any pollutant into State waters through the city-owned storm sewer system from the State department of health. (m) Notification of completion. The permittee or the permittee’s agent shall notify the director of planning and permitting or the director’s representative when the grading operation is ready for final inspection. Final approval shall not be given until completion of all work including installation of all drainage structures and their protective devices, completion of all planting showing a healthy growth in conformance with the approved plans and specifications, and the required reports have been submitted. (n) Report after grading. (1) When grading involves cuts or fills for which an engineer’s soils report was required, the permittee shall submit a final report, prepared by an engineer, upon the completion of such work. This report shall contain: (A) A description of materials used in the fill and its moisture content at the time of compaction, the procedure used in depositing and compacting the fill, the preparation of original ground surface before making the fill, but not limited to benching and subsurface drainage, and a plan or tabulation showing the general location and elevation of compaction tests made in the fill together with a tabulation of relative compaction densities obtained at each location, the location of subdrains and other pertinent features of the fill necessary for its stability; and (B) A certification that the work was done in conformity to this chapter, the approved plans and specifications, and the engineer’s soils report. (2) Where a slope hazard evaluation and mitigation plan was required to be submitted with a grading permit application, the permittee shall submit a final assessment report, prepared by an engineer, upon the completion of site work, before building construction. The assessment report shall contain a verification that the prevention measures and any stabilization measures called for in the engineering slope hazard report or construction plans were done in conformity with this chapter, and the approved plans and specifications. (o) As-graded plan. Upon completion of grading areas over 1 acre or areas graded under subdivision rules, an as-graded plan prepared by an engineer or land surveyor shall be submitted if required by the director of planning and permitting. )