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Table 6. Low Floor and Low Entry Freeboard Requirements h. Within a landlocked basin, lowest floor elevations must be at least one foot above the surveyed basin overflow elevation. Where a structure is proposed below the runoff elevation of a land -locked basin, the low -floor elevation will be a minimum of two feet above the high water level as determined from an estimate of high water levels determined from the highest of either the 100 -year, ten-day runoff event or back-to-back 100 -year, 24-hour rainfalls. Aerial photos, vegetation, soils, and topography will be used to derive a "normal" water elevation for the basin for the purpose of computing the 100 -year elevation. 7) Drainage and utility easements. a. If a stormwater management plan involves direction of some or all runoff off of the site, it shall be the responsibility of the applicant to obtain from adjacent property owners any necessary easements or other property interests concerning flowage of water. b. Easements are required for all stormwater management facilities, stormwater conveyances and on-site floodplain and shall extend a minimum of 10 feet beyond the basin's 100 -year storm high water level elevation. c. Easements are required for all outlet swales and ditches, and for overland overflow routes located downstream of basins located on site. d. If the storm sewer is to be installed less than ten feet deep within private property, the easement shall be a minimum of 20 feet wide. If the storm sewer is ten feet or greater, the easement shall be twice as wide as the depth. e. Easements necessary for maintenance vehicle access are required for all of the above where not directly available on a public road. 8) Stormwater management plan required exhibits. The stormwater management plan shall be prepared and signed by a duly licensed engineer in the State of Minnesota. The following exhibits must accompany the permit application: two plan sets, full size (22 inches by 34 inches); one plan set, reduced to maximum size of 11 inches by 17 inches. Additional copies may be draft 06-15 ECS Ordinance.docx 23/29 Regional Elevations Local Detention Basins & Wetlands Infiltration Basins Rain Gardens Groundwater Elevation 100 year EOF 100 year EOF Bottom 100 year EOF EOF Seasonal High Level Low Floor 2 -ft 1 -ft 0 -ft N/A 0 -ft N/A N/A N/A 4 -ft Low Entry NA NA 2 -ft 1 -ft NA 2 -ft 1 -ft 0.5 -ft N/A h. Within a landlocked basin, lowest floor elevations must be at least one foot above the surveyed basin overflow elevation. Where a structure is proposed below the runoff elevation of a land -locked basin, the low -floor elevation will be a minimum of two feet above the high water level as determined from an estimate of high water levels determined from the highest of either the 100 -year, ten-day runoff event or back-to-back 100 -year, 24-hour rainfalls. Aerial photos, vegetation, soils, and topography will be used to derive a "normal" water elevation for the basin for the purpose of computing the 100 -year elevation. 7) Drainage and utility easements. a. If a stormwater management plan involves direction of some or all runoff off of the site, it shall be the responsibility of the applicant to obtain from adjacent property owners any necessary easements or other property interests concerning flowage of water. b. Easements are required for all stormwater management facilities, stormwater conveyances and on-site floodplain and shall extend a minimum of 10 feet beyond the basin's 100 -year storm high water level elevation. c. Easements are required for all outlet swales and ditches, and for overland overflow routes located downstream of basins located on site. d. If the storm sewer is to be installed less than ten feet deep within private property, the easement shall be a minimum of 20 feet wide. If the storm sewer is ten feet or greater, the easement shall be twice as wide as the depth. e. Easements necessary for maintenance vehicle access are required for all of the above where not directly available on a public road. 8) Stormwater management plan required exhibits. The stormwater management plan shall be prepared and signed by a duly licensed engineer in the State of Minnesota. The following exhibits must accompany the permit application: two plan sets, full size (22 inches by 34 inches); one plan set, reduced to maximum size of 11 inches by 17 inches. Additional copies may be draft 06-15 ECS Ordinance.docx 23/29