20.540.050 Performance Standards.
A. Site area. When the activity includes both extractions and one or more of the conditional uses listed in Section 20.540.030 (B) VMC, the total site area shall be a minimum of 20 acres. Activities that are limited to extractions only shall not have a minimum site size.
B. Lot width. There shall be a minimum lot width of 330’ , unless the activity does not include any one of the uses listed in Section 20.540.030 (B) VMC, in which case, there shall be a minimum lot width of 60’ .
C. Fencing. The periphery of all sites within the site area being actively mined or reclaimed shall be fenced according to the State Department of Natural Resources standards.
D. Berms. Berms of sufficient height, width, and mass to screen the site from adjacent land uses shall be provided. Suitable planting shall be determined by the Planning Official during site plan review.
E. Setbacks. The tops and toes of cut and fill slopes shall be set back from property boundaries according to the State Department of Natural Resources’ standards for safety of the adjacent properties, and to prevent damage resulting from water runoff or erosion of slopes.
F. Maximum permissible noise levels. Maximum permissible noise levels shall be according to the provisions of the 173-60 WAC.
G. Hours of operation. Hours of operation, unless otherwise authorized or restricted by the Planning Official, shall be between 7 a.m. and 7 p.m.
H. Excavations to water-producing depth. The intent of this provision is to allow reclamation of the land that will result in the establishment of a lake of sufficient area and depth of water to be useful for residential or recreational purposes. All excavations must either be made to a water-producing depth, or graded in a manner approved by the City Engineer. The excavations made to a water-producing depth shall be reclaimed in the following manner:
1. The depth of the excavations must not be less than 2’ measured below the low-water mark.
2. All banks shall be sloped to the water line no steeper than 1-1/2’ horizontal to 1’ vertical.
3. All banks shall be sloped from the low-water line into the pond or lake with a minimum slope of 1-1/2’ horizontal to 1’ vertical, to a depth of 5’ .
4. In no event shall the term “water-producing depth,” as herein used, be construed to allow stagnant or standing water to collect or remain in the excavation.
I. Slope. When reclaimed, no slope of cut and fill surfaces shall be steeper than is safe for the intended use, and shall not exceed 1-1/2’ horizontal to 1’ vertical for gravel, and ¼’ horizontal to 1’ vertical, unless otherwise approved by the City Engineer for consolidated material.
J. Erosion control. All disturbed areas including faces of cuts and fill slopes, shall be prepared and maintained to control erosion. This control may consist of planting sufficient in amount or type to stabilize the slope as approved by the Planning Official.
K. Drainage. Provisions shall be made to:
1. Prevent any surface water or seepage from damaging the cut face of any excavations or the sloping face of a hill.
2. Drain any surface waters that are or might be concentrated as a result of a fill or excavation to a natural watercourse, or by other means approved by the City Engineer.
3. Prevent any sediment from leaving the site in a manner which violates 90.48.080 RCW and 173-201-100 WAC.
L. Bench/terrace. Benches shall be back-sloped, and shall be established at not more than 40’ vertical intervals, to control surface drainage and debris. Swales or ditches on benches shall have a maximum gradient of 5%.
M. Maintenance of access roads. Access roads to mining and quarrying sites shall be maintained and located to the satisfaction of the City Engineer, to minimize problems of dust, mud and traffic circulation.
N. Overburden. Overburden shall only be removed to accommodate aggregate and related activities of this chapter.
O. Land restoration.
1. Upon the exhaustion of minerals or materials, or upon the permanent abandonment of the quarrying or mining operation, all buildings, structures, apparatus or appurtenances accessory to the quarrying and mining operation which are nonconforming to the underlying district, shall be removed or otherwise dismantled to the satisfaction of the Planning Official by means of a Type I procedure.
2. Final grades shall be such so as to encourage the uses permitted by right or allowed conditionally within the base zoning district.
3. Unless approved as a sanitary landfill, grading or backfilling shall be made with nonnoxious, nonflammable and noncombustible solids.
4. Such graded or backfilled areas, except for roads, shall be seeded or surfaced with soil of a quality at least equal to the topsoil of the land areas immediately surrounding, and to a depth of at least 4”, or a depth of that of the topsoil of land areas immediately surrounding, if less than 4”.
5. Such topsoil as required by Subsection 4 above shall be planted with trees, shrubs or grasses.
6. Graded or backfilled areas shall be reclaimed in a manner that will not permit stagnant water to remain. Suitable drainage systems approved by the City Engineer shall be constructed or installed if natural drainage is not possible.
7. Waste or soil piles shall be leveled and the area treated, as required in Subsections 4 and 5 above. (Ord. M-3643, 01/26/2004)