1. PURPOSE. To preserve open space and natural uses of lands which are unsuitable for intensive urban development purposes due to poor natural soils conditions, poor drainage, and the need to preserve floodplain storage. The regulation of the se areas will serve to maintain and improve water quality, prevent flood damage, protect wildlife habitat, and prohibit the location of structures on soils which are generally not suited for such use. In delineating the FSO district, consideration shall be given to the maintenance of flood storage capacity and preventing significant increases in the flood discharges identified in the Flood Insurance Study--City of Waukesha, Waukesha County, Wisconsin, dated March 2, 1982. Significant increases are those which result in a rise of the regional flood profile of 0.01 foot or more.
2. PERMITTED PRINCIPLE USES.
   1. Drainage.
   2. Functionally water dependent uses such as docks or wharves.
   3. Historic structures provided that said structure was in existence within the Flood Storage Overlay District prior to the adoption of this section.
   4. Movement of floodwater.
   5. Navigation.
   6. Stream bank protection.
   7. Water measurement and control facilities.
   8. Any of the following uses are permitted provided that they are permitted uses in the underlying basic use district, and further provided that such use shall not involve the erecting or placing of a structure.
      1. Horticulture.
      2. Local streets, provided that no street shall not be subject to inundation depths greater than two (2) feet or flood velocities greater than two (2) feet per second.
      3. Open markets.
      4. Open recreational uses, such as parks, sport fields, beaches, bathing, hunting, fishing, rinks, golf courses, and driving ranges.
      5. Outdoor plant nurseries.
      6. Parking and loading areas, provided that no such area shall not be subject to inundation depths greater than two (2) feet or flood velocities greater than two (2) feet per second.
      7. Sod Farms.
      8. Truck farming.
      9. Utility poles, towers, and underground conduit for transmitting electricity, telephone, cable television, natural gas, and similar products and services.
      10. Grape growing.
      11. Wildlife preserves.
3. CONDITIONAL USES.
   1. Open space and related uses for the following uses numerated below provided that the applicant shows that such use or improvement will not impede drainage; will not cause ponding; will not obstruct the floodway; will not increase flood flow velocities; will not increase the flood stage; and will not retard the movement of floodwaters. Structures, when permitted shall be floodproofed in accordance with Section 22.58(11) to the flood protection elevation and shall be anchored to protect them from larger floods. Certification of floodproofing shall be made to the Building Inspector and shall consist of a plan or document certified by a registered professional engineer or registered architect that the floodproofing measures are consistent with the flood velocities, forces, depths, and other factors associated with the 100-year recurrence interval flood.
      1. Navigational structures.
      2. Public water measuring and control facilities.
      3. Bridges and approaches.
      4. Marinas.
      5. Filling as authorized by the Wisconsin Department of Natural Resources to permit the establishment of approved bulkhead lines.
      6. Other open space uses consistent with the purpose and intent of the district and compatible with uses in adjacent districts, not including structures.
   2. Accessory structures provided that any structures are not designed for human habitation, have a low flood damage potential, are constructed and placed to provide minimum obstruction to flood flows and are firmly anchored to prevent them from floating away and restricting bridge openings, and have all service facilities, such as electrical and heating equipment, at an elevation of at least two (2) feet above the 100-year recurrence interval flood. Whenever possible, accessory structures shall be placed with their longitudinal axis parallel to the flow of floodwaters. Certification of floodproofing shall be made to the Building Inspector and shall consist of a plan or document certified by a registered professional engineer or registered architect that the floodproofing measures are consistent with the flood velocities, forces, depths, and other factors associated with the 100-year recurrence interval flood.
   3. Municipal water supply and municipal sewerage collection systems, provided that the system is floodproofed in accordance with Section 22.58(11) to an elevation of at least two (2) feet above the elevation of the 100-year recurrence interval flood, and is designed to eliminate or minimize infiltration of floodwaters into the system. All floodproofed utilities shall be anchored to prevent floatation. Certification of floodproofing shall be made to the Building Commissioner and shall consist of a plan or document certified by a registered professional engineer or registered architect that the floodproofing measures are consistent with the flood velocities, forces, depths, and other factors associated with the 100-year recurrence interval flood level for the particular stream reach.
   4. Floodplain boundary adjustments provided that an equal volume of storage--as defined by the ground surface of the 100-year recurrence interval flood elevation--shall be provided to compensate for the volume of storage which is lost. Lands removed from the floodplain by floodplain boundary adjustment shall be filled to an elevation of at least two (2) feet above the elevation of the 100-year recurrence interval flood and such lands shall be contiguous to lands lying outside of the floodlands. Excavation below the groundwater table shall not be considered as providing an equal volume of storage. Compensating storage shall not be provided on lands owned by others unless appropriate legal arrangements have been entered into with all property owners affected by the modification. Lands affected by limited floodplain boundary adjustments may be removed from or added to the Flood Storage Overlay District provided that the property owner, or his agent, has compiled with all the requirements for amending the zoning map.
   5. Wireless communications facilities as set forth and under conditions authorized in Section 22.21.
4. PROHIBITED ACTIVITIES.
   1. Dumping and Filling. Lands lying within the Flood Storage Overlay District shall not be used for dumping or be filled except as authorized to permit establishment of approved bulkhead lines or to accommodate bridge approaches. Normal earth grading activities to permit utilization of the lands for open space, outdoor recreation, yard, parking, and similar uses are permitted.
   2. Dangerous Materials Storage. Lands lying within the Flood Storage Overlay District shall not be used for the storage of materials that are buoyant, flammable, explosive, or injurious to human, animal, or plant life. Semi-tractors and their trailers shall not be stored or parked in the Flood Storage Overlay District.
   3. Incompatible Uses. Lands lying within the Flood Storage Overlay District shall not be used for any solid waste disposal site or on site soil absorption sanitary sewerage system site, or the construction of any well which is used to obtain water for ultimate human consumption. Sewage treatment plants and treatment ponds shall not be constructed in the Flood Storage Overlay District.
   4. Mobile Homes. No mobile home, manufactured home, mobile home park, or trailer camp shall be placed or moved onto lands lying in the Flood Storage Overlay District.
5. MAINTENANCE OF DRAINAGEWAYS. No development in the Flood Storage Overlay District shall increase flood stages as determined by the Flood Insurance Study--City of Waukesha, Waukesha County, Wisconsin, dated March 2, 1982, or amendments thereto, decrease flood storage, or increase flood velocity as determined by the federal Flood Insurance Study or amendments thereto, in the channels, floodways, or shorelands of the Fox River, Pebble Brook Tributary, Pebble Creek, any tributary thereto, or drainage ditches. No development in the Flood Storage Overlay District shall increase the areal extent of the floodplain to other lands lying outside the floodlands unless compensating storage agreements have been entered into.
6. FLOODLANDS USED FOR DENSITY CALCULATION. Where a lot is located partially within a Flood Storage Overlay District and partially within an adjoining use district, that area of the parcel in the Flood Storage Overlay District may be used to meet the minimum lot area requirements of the adjoining use district provided that not more than twenty percent (20%) of the lot area requirement may be met by the use of Flood Storage Overlay District lands.

(Cr. #66-01)