01/25/2011 Env Bd Packet - Laserfiche WebLink

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DRAFT 01 -19 -2011 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 runout 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. JIM WILL REVIEW WITH RCWD (f) All stormwater management structures and facilities must be designed for maintenance access and properly maintained in perpetuity to assure that they continue to function as designed. (g) Before work under the permit is deemed complete, as- builts must be submitted demonstrating that at the time of final stabilization, stormwater facilities conform to design specifications. (9) 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 10 feet deep within private property, the easement shall be a minimum of 20 feet wide. If the storm sewer is 10 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. (10) Exceptions. Alternative Format 18 • • Regional Elevations Detention Basins & Wetlands Infiltration Basins Rain- gardens Ground Water Elevation 100yr EOF 100yr EOF Bottom 100yr EOF EOF Bottom Low Floor Freeboard 2 -ft 1 -ft 0 -ft NA 0 -ft NA NA NA 4 -ft Low Entry Freeboard NA NA 2 -ft 1 -ft NA 2 -ft 1 -ft 0.5 -ft NA 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 runout 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. JIM WILL REVIEW WITH RCWD (f) All stormwater management structures and facilities must be designed for maintenance access and properly maintained in perpetuity to assure that they continue to function as designed. (g) Before work under the permit is deemed complete, as- builts must be submitted demonstrating that at the time of final stabilization, stormwater facilities conform to design specifications. (9) 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 10 feet deep within private property, the easement shall be a minimum of 20 feet wide. If the storm sewer is 10 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. (10) Exceptions. Alternative Format 18 • •