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(g) Within a landlocked basin, lowest floor elevations must be at least one foot above the surveyed <br />basin overflow elevation. Where a structure is proposed below the runoff elevation of a land-locked basin, <br />the low-floor elevation will be a minimum of two feet above the high water level as determined from an <br />estimate of high water levels determined from the highest of either the 100-year, ten-day runoff event or <br />back-to-back 100-year, 24-hour rainfalls. Aerial photos, vegetation, soils, and topography will be used to <br />derive a "normal" water elevation for the basin for the purpose of computing the 100-year elevation. <br /> (7) Drainage and utility easements. <br /> (a) If a stormwater management plan involves direction of some or all runoff off of the site, it shall be <br />the responsibility of the applicant to obtain from adjacent property owners any necessary easements or <br />other property interests concerning flowage of water. <br /> (b) Easements are required for all stormwater management facilities, stormwater conveyances and on- <br />site floodplain and shall extend a minimum of ten feet beyond the basin's 100-year storm high water level <br />elevation. <br /> (c) Easements are required for all outlet swales and ditches, and for overland overflow routes located <br />downstream of basins located on site. <br /> (d) If the storm sewer is to be installed less than ten feet deep within private property, the easement <br />shall be a minimum of 20 feet wide. If the storm sewer is ten feet or greater, the easement shall be twice as <br />wide as the depth. <br /> (e) Easements necessary for maintenance vehicle access are required for all of the above where not <br />directly available on a public road. <br /> (8) Stormwater management plan required exhibits. The stormwater management plan shall be prepared <br />and signed by a duly licensed engineer in the State of Minnesota. The following exhibits must accompany <br />the permit application: two plan sets, full size (22 inches by 34 inches); one plan set, reduced to maximum <br />size of 11 inches by 17 inches. Additional copies may be required in accordance with applicable zoning and <br />subdivision provisions of city code. All plan sets shall also be submitted electronically in a .dwg format or <br />as otherwise determined by the City Engineer. The minimum information requirements of the stormwater <br />management plan shall be consistent with the most recent version of the NPDES permit requirements and <br />include the following information: <br /> (a) A grading, erosion and sediment control plan and, for projects that require a NPDES permit, a <br />stormwater pollution prevention plan (SWPPP) is required; <br /> (b) Stormwater management plan including existing and proposed hydrologic calculations for total <br />runoff volume and peak discharge rates as described in this chapter, including: <br /> 1. A narrative including a project description, discussion of BMP selection, incorporation of <br />infiltration BMPs, and revegetation plan for the project site; <br /> 2. Delineation of all drainage areas, including contributing runoff from off-site areas, proposed and <br />existing subwatersheds on-site, emergency overflows, and drainage ways; <br /> 3. Existing, proposed, and total amount of impervious surfaces created by the project; <br /> 4. Existing and proposed runoff curve numbers; <br /> 5. Time of concentration used in calculations; and <br /> 6. Existing and proposed total runoff volume and peak discharge rates for the two-, ten-, and 100- <br />year critical events utilizing NOAA Atlas 14. <br /> (c) Property of lines and delineation of lands under ownership of the applicant.