17.05.150 Dust control. All graded surfaces and materials, whether filled, excavated, transported or stockpiled, shall be wetted, protected or contained in such a manner to prevent dust or spillage upon adjacent property or streets. Equipment, material and roadways on the site shall be used in such manner or so treated as to prevent excessive dust conditions. (Ord. 16432 § 6(2), 3-10-92. Code 1995 § 66-122.) 17.05.160 Slope of cut surfaces. The slope of cut surfaces shall be no steeper than is safe for the intended use and shall be no steeper than three horizontal to one vertical unless approved by the department of public works. (Ord. 16432 § 6(3), 3-10-92. Code 1995 § 66-123.) 17.05.170 Fills. (a) Fill Location. Fill slopes shall not be constructed on natural slopes steeper than three to one unless approved by the department of public works. (b) Preparation of Ground. The ground surface shall be prepared to receive fill by removing vegetation, noncomplying fill, topso