Chapter 15.16
GRADING, EXCAVATION AND FILL
Sections:
15.16.030 Regulated activities.
15.16.050 Permit application and submittals.
15.16.090 Drainage, benching and terraces.
15.16.110 Permitted work hours.
15.16.010 Purpose.
The purpose of this chapter is to protect, maintain and enhance the public health, safety and general welfare by establishing minimum requirements and procedures to control the adverse impact associated with earthwork grading activity.
Grading activity specifically associated with building construction shall comply with International Building Code Chapter 18, Sections 1803 and 1804. (Ord. 3575 § 4, 2012).
15.16.020 Definitions.
Words and phrases used in this chapter have the meaning set forth in this section. The definitions found within MVMC 14.05.220 are hereby adopted by reference in their entirety as they are currently written or as they may be amended in the future.
A. “Bench” means a relatively level step excavated into the earth material on which fill is to be placed.
B. “Compaction” means the densification of a fill by mechanical means.
C. “Cut” is the removal of earth material by artificial means, also referred to as an excavation.
D. “Erosion” is the wearing away of the ground surface as a result of the movements of wind, water, ice or other geological agents, including such processes as gravitational creep.
E. “Excavation” means the removal of earth material by artificial means, also referred to as a cut.
F. “Fill” is the deposition of earth materials by artificial means.
G. “Grade” is the vertical location of the ground surface.
H. “Grading” or “graded” is the importing, exporting, stockpiling or moving of materials on, off or through a site. Digging trenches for utility installation is considered grading.
I. “Grade, existing” is the grade prior to grading activity.
J. “Grade, finished” is the grade of the site at the conclusion of all grading efforts.
K. “Key” is a compacted fill placed in a trench excavated in earth material beneath toe of a slope.
L. “Pipe slope drain” refers to a device for collecting water from a swale or ditch located on or above a slope, and safely delivering it to an approved drainage facility.
M. “Scarify” means to abrade, scratch or break up the surface of the soil so that fill material will bind to the surface.
N. “Slope” is an inclined surface, the inclination of which is expressed as a ratio of horizontal distance to vertical distance.
O. “Terrace” is a relatively level step constructed in the face of a graded slope for drainage and maintenance purposes.
P. “Turbidity, allowable” refers to the DOE designation of no greater than five nephelometric turbidity units (NTU) over background turbidity when the background turbidity is 50 NTU or less, or no more than 10 percent increase in turbidity when the background turbidity is more than 50 NTU. (Ord. 3575 § 5, 2012).
15.16.030 Regulated activities.
A. No grading shall be performed without first having obtained a fill and grade permit issued by the community and economic development department.
B. A fill and grade permit shall not be required for the following:
1. Excavation or fill for construction of a structure permitted under a building permit. This exception is only for grading associated with the foundation of a structure, not other site grading that may be necessary.
2. Grading of less than 50 cubic yards of material located outside of a critical area or critical area buffer.
3. Grading of agricultural fields for agricultural related activities.
4. Grading activity performed during a flooding emergency in an effort to protect life or property.
5. Grading associated with the creation of cemetery graves.
C. Exemption from permit requirements of this chapter shall not be deemed to grant authorization for any work to be done in any manner in violation of the provisions of this code or any other laws or ordinances of the city of Mount Vernon. (Ord. 3575 § 6, 2012).
15.16.040 General provisions.
A. All grading design and construction activity shall comply with this code and all Mount Vernon Municipal Code provisions, including but not limited to Chapter 13.33 MVMC, Storm Water Drainage Utility, and Chapter 15.40 MVMC, Critical Areas. In case of conflict the more stringent code shall apply.
B. All grading design and construction activity shall comply with the city of Mount Vernon Engineering Standards as they are currently written and as they may be amended in the future.
C. No grading activity may occur within a critical area or critical area buffer without specific approval for this activity.
D. A safety fence may be required around grading activities on a project site.
E. It shall be the responsibility of both the permittee and the property owner to advise the city immediately of any discrepancies, hazardous conditions or problems affecting safety and stability of the project. (Ord. 3575 § 7, 2012).
15.16.050 Permit application and submittals.
A. All permit submittals shall include the submittal materials outlined within Chapter 14.05 MVMC for fill and grade I and fill and grade II permits.
B. All permit submittals shall identify source of fill material and destination of excavated material. The property owner of any off-site location the excavated material is to be placed may be required to obtain a fill and grade permit from the appropriate jurisdiction.
C. The geotechnical report prepared by a licensed engineer shall be provided and shall contain at a minimum the following:
1. The nature and distribution of existing soils;
2. Conclusions and recommendations for grading procedures;
3. Soil design criteria for any structures or embankments required to accomplish the proposed grading; and
4. Where necessary, slope stability studies, and recommendations and conclusions regarding site geology.
D. A geotechnical report is not required when the project includes placement of material with less than four-foot vertical lift and the existing and proposed slopes are not steeper than 3:1, or, where the building code official determines that the nature of the work applied for is such that a report is not necessary. (Ord. 3575 § 8, 2012).
15.16.060 Excavations.
Unless otherwise recommended in the geotechnical report, excavations shall comply with the provisions of this section.
A. The slope of cut surfaces shall be no steeper than is safe for the intended use, and shall not be steeper than three units horizontal to one unit vertical (3:1).
B. A cut surface in bedrock shall be permitted to be at a slope of one unit horizontal to one unit vertical (1:1). (Ord. 3575 § 9, 2012).
15.16.070 Fills.
Unless otherwise recommended in the geotechnical report, fills shall comply with the provisions of this section.
A. The slope of fill surfaces shall be no steeper than is safe for the intended use, and shall not be steeper than three units horizontal to one unit vertical (3:1).
B. All fill material shall meet the standard for the intended future use. Material to be placed in areas of future building site shall be structural fill material. Testing shall be required as deemed necessary by the city of Mount Vernon.
C. The ground surface shall be prepared to receive fill by removing vegetation, topsoil and other unsuitable materials, and scarifying the ground to prove a bond with the fill material. Fill material shall not include organic, frozen or other deleterious materials. No rock or similar irreducible material greater than 12 inches in any dimension shall be included in fills.
D. All fill material shall be compacted at a minimum to 90 percent of maximum density as determined by ASTMD 1557 modified proctor, in lifts not exceeding 12 inches in depth. Tests to determine the density of compacted fills shall be made on the basis of not less than one test per 7,000 square feet of compacted area per two-foot vertical lift. Additional testing may be required at the direction of the city inspector.
E. Compaction of temporary stockpile fills shall not be required, except where the building official determines that compaction is necessary as a safety measure. (Ord. 3575 § 10, 2012).
15.16.080 Setbacks.
A. Property location and approved setbacks must be established and stakes set under the supervision of a registered land surveyor when grading activities occur that are regulated under this chapter. Those stakes must be maintained in place until final inspection of works so that the inspector can determine at any time if the excavation is properly located as related to property lines.
B. Setback dimensions shall be measured perpendicular to the property line.
C. The setback at the top of a cut slope shall not be less than five feet or than is required to accommodate any required interceptor drains, whichever is greater.
D. The toe of a slope distance to property and easement lines shall be as follows:
1. For slopes less than 11 feet in height the minimum distance shall be five feet.
2. For slopes 11 feet in height or greater the minimum distance shall be height divided by two.
E. The top or toe of a slope distance to a structure shall be not less than 10 feet. (Ord. 3575 § 11, 2012).
15.16.090 Drainage, benching and terraces.
A. Drainage shall be provided in accordance with Chapter 13.33 MVMC and Engineering Standards as they are currently written or as they may be amended in the future.
B. Terracing and benching shall be provided as recommended in the geotechnical report.
C. Interceptor drains shall be installed along the top of cut slopes receiving drainage from a tributary width greater than 40 feet, measure horizontally. Drains shall be constructed of solid, not flexible, pipe.
D. Down drains shall terminate into a catch basin or other approved receiver to prevent scouring at the outfall. (Ord. 3575 § 12, 2012).
15.16.100 Erosion control.
A. Erosion and sediment control shall be provided in accordance with Chapter 13.33 MVMC, Engineering Standards Chapter 2 and 2005 Washington State Department of Ecology Stormwater Management Manual for Western Washington.
B. Temporary erosion control shall be installed if an area is to remain unworked for more than seven days during the dry season (May 1st to September 30th) or for more than two days during the wet season (October 1st to April 30th).
C. Permanent erosion control shall be applied to any area to remain unworked for more than 30 days. Disturbed soils shall be stabilized prior to final inspection.
D. If during the course of grading activity during the seasonal limitation period of October 1st through April 30th silt laden runoff in excess of allowable turbidity leaves the site or if clearing and grading limits or erosion sediment control measures shown in the approved plan are not maintained, the city inspector shall have the responsibility and authority to issue a partial or complete stop work order.
E. For construction sites one acre or larger a certified erosion and sediment control lead shall be identified for the project and shall be on call at all times. The name and phone number of the contact person shall be posted on site.
F. No tracking of mud or debris on to public streets is allowed. (Ord. 3575 § 13, 2012).
15.16.110 Permitted work hours.
All grading activity is limited to the hours between 7:00 a.m. and 9:00 p.m. Monday through Friday and 8:00 a.m. and 9:00 p.m. Saturday and Sunday. The building official is authorized to grant an extension of working hours. (Ord. 3575 § 14, 2012).
15.16.120 Inspection.
A. All activities regulated by this chapter shall be inspected by the public works director and/or building official or their designees.
B. Projects shall be inspected at various stages of the work to determine that adequate control is being exercised. Stages of work subject to inspection include, but are not limited to: pre-construction, erosion control, grading activities, installation of utilities, storm water facilities, retaining walls, landscaping and completion of project. (Ord. 3575 § 15, 2012).
15.16.130 Hazards.
Whenever the building official determines that a proposed or existing excavation, embankment, or fill on any land within the city of Mount Vernon is or may become a hazard to life or limb, endangers property, adversely affects the environment or the safety, use, or stability of a public way, or adversely affects a drainage channel or other natural watercourse by siltation, erosion diversion, concentration, or an increase in storm water runoff, the owner of the property upon which the excavation or fill is located or other person or agent in control of said property shall upon receipt of notice from the building official repair or eliminate such excavations, embankments, or fill so as to eliminate the hazard and be in conformance with the requirements of this code. (Ord. 3575 § 16, 2012).
15.16.140 As built plans.
As built plans shall be submitted to the city of Mount Vernon prior to final inspection and approval. (Ord. 3575 § 17, 2012).