A. Clearing Permits. A permit is required and shall be issued in accordance with Section 24.10.070 for clearing activities in the following areas:

1. The Tualatin River sub-basins, Johnson Creek Basin Plan District, environmental zones, greenway zones, or natural resource management plans; or

2. Property larger than five acres. Except that no permit shall be required for clearing an area less than 5,000 square feet.

B. Grading Permits. A permit is required and shall be issued in accordance with Section 24.10.070 for all grading operations with the exception of the following:

1. Grading in an area, where in the opinion of the Director, there is no apparent danger, adverse drainage, or erosion effect on private/public property, or inspection is not necessary;

2. An excavation below finished grade for basements and footings of a building, retaining wall, or other structure authorized by a valid building permit. This shall not exempt any fill made with the material from such excavation nor exempt any excavation having an unsupported height greater than 5 feet after the completion of such structure.

3. Cemetery graves.

4. Refuse disposal sites controlled by other regulations.

5. Excavations for wells or tunnels.

6. Mining, quarrying, excavating, processing, stockpiling of rock, sand, gravel, aggregate, or clay where established and provided for by law provided such operations do not affect the lateral support or increase the stresses in or pressure upon any adjacent or contiguous property.

7. Exploratory excavations under the direction of soil (geotechnical) engineers or engineering geologists.

8. An excavation which

a. Is less than 2 feet in depth, or

b. Which does not create a cut slope greater than 5 feet in height and steeper than 1-1/2 horizontal to 1 vertical.

9. A fill less than 1 foot in depth, and placed on natural terrain with a slope flatter than 5 horizontal to 1 vertical, or less than 3 feet in depth, not intended to support structures, which does not obstruct a drainage course and which does not exceed 10 cubic yards on any one lot.

C. Tree cutting permit. A tree cutting permit is required for tree cutting (except Christmas trees) and root grubbing operations on slopes with gradients which, in whole or in part, exceed 25%. This regulation applies when more than five trees of six-inch diameter are to be cut or if the area to be cleared is greater than 2,500 square feet. This applies in all areas except those designated environmental zones under the provisions of Title 33. Tree cutting permits shall be issued in accordance with Section 24.10.070.

1. Plans and specifications showing the scope of proposed tree cutting operations, together with a geotechnical engineering report assessing the stability of the slope(s) after both tree felling and root grubbing operations shall be submitted to the Director along with the permit application.

2. Stripping of vegetation or other soil disturbance on the slopes shall be done in a manner which will minimize soil erosion and expose the smallest practical area at any one time. An erosion control and mitigation plan outlining how this is to be achieved and what erosion control measures are proposed to be implemented shall be submitted to the Director for approval.

3. The permit applicant shall also identify the owner’s agent who will be responsible for ensuring compliance with these requirements.