A. Plans Required: Proposed subdivisions shall be carefully planned to be compatible with natural topography, soil conditions, geology and hydrology of the site, as well as to minimize cuts, fills, alterations of topography, streams, drainage channels and disruption of soils or vegetation. Fill within the floodplain shall comply with the requirements of the flood hazard overlay district of the zoning ordinance.
1. A preliminary soil report prepared by a qualified engineer may be required by the hearing examiner or commission and/or council as part of the preliminary plat application.
2. A preliminary grading plan prepared by a civil engineer may be required by the hearing examiner or commission and/or the council as part of the preliminary plat application, to contain the following information:
a. Proposed contours at a maximum of two foot (2') contour intervals;
b. Cut and fill banks in pad elevations;
c. Drainage patterns;
d. Areas where trees and/or natural vegetation will be preserved;
e. Location of all street and utility improvements, including driveways to building envelopes; and
f. Any other information which may reasonably be required by the administrator, hearing examiner, commission and/or council.
B. Design Standards: The proposed subdivision shall conform to the following design standards:
1. Grading shall be designed to blend with natural landforms and to minimize the necessity of padding or terracing of building sites, excavation for foundations, and minimize the necessity of cuts and fills for streets and driveways.
2. Areas within a subdivision which are not well suited for development because of existing soil conditions, steepness of slope, geology or hydrology shall be allocated for green space for the benefit of future property owners within the subdivision.
3. Where existing soils and vegetation are disrupted by subdivision development, provision shall be made by the developer for revegetation of disturbed areas with perennial vegetation sufficient to stabilize the soil upon completion of the construction, including temporary irrigation for a sufficient period to establish perennial vegetation. Until such time as the vegetation has been installed and established, the developer shall maintain and protect all disturbed surfaces from erosion.
4. Where cuts, fills or other excavation are necessary, the following development standards shall apply:
a. Fill areas for structures or roads shall be prepared by removing all organic material detrimental to proper compaction for soil stability.
b. Fill for structures or roads shall be compacted to at least ninety five percent (95%) of maximum density as determined by American Association Of State Highway And Transportation Officials (AASHTO) and American Society For Testing Materials (ASTM).
c. Cut slopes shall be no steeper than two horizontal to one vertical (2:1). Subsurface drainage shall be provided as necessary for stability.
d. Fill slopes shall be no steeper than three horizontal to one vertical (3:1). Neither cut nor fill slopes shall be located on natural slopes of three to one (3:1) or steeper, or where fill slope toes out within twelve feet (12') horizontally of the top of existing or planned cut slope.
e. Tops and toes of cut and fill slopes shall be set back from structures and property lines as necessary to accommodate drainage features and drainage structures.
5. The developer shall provide storm sewers and/or drainage areas of adequate size and number to contain the runoff upon the property in conformance with the applicable federal, state and local regulations. The developer shall provide copies of state permits for shallow injection wells (dry wells). Drainage plans shall be reviewed by planning staff and shall meet the approval of the city engineer. Developer shall provide a copy of EPA's "NPDES General Permit For Stormwater Discharge From Construction Activity" for all construction activity affecting more than one acre. (Ord. 1191, 2015)