A. Cut slopes can be no steeper than necessary, but shall in no case be steeper than two feet horizontal to one foot vertical.
B. No cut slope shall be higher than thirty feet unless approved by the director of public services.
C. The top of the excavation slope shall not be closer than three feet to the site boundary.
D. Slopes less than thirty percent shall require six inches of topsoil on all nonpaved areas. Topsoil shall satisfy the following requirements:
1. Criteria.
a. United States Department of Agriculture Classifications: Topsoil shall be sandy loam, sandy clay loam or loam containing: twenty-five to eighty percent sand (0.02 - 2.0 mm), and zero to fifty percent silt (0.002 - 0.05 mm), and ten to thirty percent clay (0 - 0.002 mm).
b. Chemistry: Significant chemistry parameters will be within the following specified ranges:
i. Salinity (ECe) 0 - 4.0
(Saturation extract conductivity)
ii. Sodium (SAR) 0 - 6.0
(Calculated sodium adsorption ratio)
iii. Boron 0 - 1.0
(Concentration in ppm of saturation extract)
iv. Reaction 5.5 - 7.0
(pH of saturated paste)
c. Organic Matter (surface to six inches) permitted range:
(percent dry weight) 2 - 5
d. Fertility: Soil to contain sufficient quantities of available nitrogen, phosphorus, potassium, calcium and magnesium to support initial normal plant growth.
e. Percolation rate: (inches per hour) 0.15 - 2.0
2. In addition to removal and replacement, the following mitigation measures are acceptable.
a. USDA Classifications: None;
b. Chemistry:
i. Salinity (ECe) may be reduced by leaching to extent required to yield a twenty-four-inch profile of nonsaline (ECe less than 4.0) soil,
ii. Sodium may be reduced by amending and leaching to extent required to yield a twenty-four-inch profile of soil with sodium adsorption ratio (SAR) less than 6.0,
iii. Boron may be reduced by leaching to extent required to yield a twenty-four-inch profile with boron concentration in saturation extract solution less than 1.0 ppm;
c. Organic matter: May be enhanced by the addition of organic soil amendments including peat moss, wood residuals or bark residuals as required to yield prescribed organic content in the surface six-inch profile;
d. Fertility: May be enhanced by fertilization extent required;
e. Retesting: Where mitigations are elected, results must be demonstrated by appropriate laboratory testing.
3. Testing: The soil samples shall be taken by developer or its agent under supervision of city staff and delivered to a city approved testing laboratory. All costs for testing shall be paid by the developer including retesting as required to demonstrate success in mitigation attempts. (Ord. 535 §2(part), 1990; Ord. 486 (part), 1986).