9.05.110 Excavations.
This section applies to all excavations in the City regardless of whether a permit is required by this ordinance for the excavations, except that the tests and reports specified by this section shall not be necessary in connection with excavations for which no permit is required.
A. Slope Standards Generally. No permanent excavation shall be made with a face steeper in slope than one and one-half horizontal to one vertical, unless a retaining wall or other approved support is provided to support the face of the excavation.
B. Deviation from Slope Standard. The city engineer may on request, permit deviations from the above standard that do not conflict with the purpose of this ordinance; provided, that the owner shall first furnish the city engineer with a written opinion of a soils engineer, certifying that the soils engineer has investigated the site and that the proposed deviations will not endanger property.
C. Flatter Excavation Face – When Required. The city engineer may require the excavation to be made with an excavation face flatter in slope than one and one-half horizontal to one vertical if the city engineer finds the material in which the excavation is to be made unusually subject to erosion or if other conditions make the flatter excavation necessary for stability and safety.
D. Erosion Control. All demolition areas, exposed slopes (excavation and fill slopes), stockpiles, grading areas and other areas of the site to be disturbed shall receive erosion control treatment meeting applicable standards of the City, Washington County Clean Water Services, and Oregon Department of Environmental Quality. In the event of a conflict or inconsistency, those standards affording the most protection to persons and property off-site shall apply. Before any area or combination of areas that exceed 500 square feet of the surface of a site is disturbed by, or for purposes of, any of the following construction activities or combination thereof, all downstream property lines of the site shall be fenced with erosion control (silt) fencing, downstream street inlets and water courses shall be protected from sedimentation, and construction vehicle accesses shall be provided with a gravel construction (wash-down) entrance pad for each access:
1. Demolition.
2. Construction staging.
3. Multiple trips by vehicles over undisturbed ground or parking of multiple construction vehicles on undisturbed ground.
4. Clearing, stripping, or removal of existing trees, vegetation, groundcover or topsoil.
5. Scraping of the ground surface, as for example, in or around a stockpile area to remove materials that would otherwise contaminate the materials to be stockpiled (such as clean fill material or clean crushed rock for roadbuilding).
6. Depositing debris.
7. Grading, excavation or filling.
8. Depositing, stockpiling or storage of soil, sand, gravel, crushed rock, demolition materials, recycled concrete, asphalt or other recycled demolition materials.
9. Pot-holing, geotechnical test drilling, exploratory excavations or well-drilling.
E. Distance from Property Line. The beginning of an excavation shall be located one-half its vertical height but not less than ten feet from an adjoining property line. Request for waiver of this requirement may be made to the city engineer by presentation of detailed plans along with appropriate substantiating evidence in the form of a written opinion of a soils engineer or engineering geologist to support justification for the waiver.
F. Rounding of Excavations Required. The top of excavations slopes and the ends of excavations shall be rounded as required by the city engineer. [BC 9.05.110, amended by Ordinance No. 4249, 4/7/03]