VOLUME 1 OF 2 JEFFERSON COUNTY, WISCONSIN, AND INCORPORATED AREAS Community Community Name Number Cambridge, Village of 550080 Fort Atkinson, City of 555554 Jefferson, City of 555561 Jefferson County, Unincorporated Areas 550191 Johnson Creek, Village of 550194 Lac LaBelle, Village of 550565 Lake Mills, City of 550195 Palmyra, Village of 550196 Sullivan, Village of 550197 Waterloo, City of 550198 Watertown, City of 550107 Whitewater, City of 550200 PRELIMINARY Federal Emergency Management Agency FLOOD INSURANCE STUDY NUMBER 55055CV001B NOTICE TO FLOOD INSURANCE STUDY USERS Communities participating in the National Flood Insurance Program have established repositories of flood hazard data for floodplain management and flood insurance purposes. This Flood Insurance Study (FIS) may not contain all data available within the repository. It is advisable to contact the community repository for any additional data. The Federal Emergency Management Agency (FEMA) may revise and republish part or all of this Preliminary FIS report at any time. In addition, FEMA may revise part of this FIS report by the Letter of Map Revision (LOMR) process, which does not involve republication or redistribution of the FIS report. Therefore, users should consult community officials and check the Community Map Repository to obtain the most current FIS components. Initial Countywide FIS Effective Date: June 2, 2009 Revised Countywide FIS Date: TBD TABLE OF CONTENTS – VOLUME 1 Page 1.0 INTRODUCTION 1 1.1 Purpose of Study 1 1.2 Authority and Acknowledgments 1 1.3 Coordination 3 2.0 AREA STUDIED 4 2.1 Scope of Study 4 2.2 Community Description 6 2.3 Principal Flood Problems 7 2.4 Flood Protection Measures 12 3.0 ENGINEERING METHODS 12 3.1 Hydrologic Analyses 12 3.2 Hydraulic Analyses 20 3.3 Vertical Datum 24 4.0 FLOODPLAIN MANAGEMENT APPLICATIONS 25 4.1 Floodplain Boundaries 25 4.2 Floodways 26 5.0 INSURANCE APPLICATIONS 56 6.0 FLOOD INSURANCE RATE MAP 56 7.0 OTHER STUDIES 57 8.0 LOCATION OF DATA 57 9.0 BIBLIOGRAPHY AND REFERENCES 60 i TABLE OF CONTENTS – VOLUME 1 (continued) Page FIGURES Figure 1 – Flood Scenes from June 21, 2008 in the City of Jefferson...........................................9 Figure 2 – Flood Scenes from June 2008 in the City of Jefferson...............................................10 Figure 3 – Flood Scenes from June 2008 in the City of Waterloo...............................................11 Figure 4 – Floodway Schematic....................................................................................................27 TABLES Table 1 – Initial and Final CCO Meetings..................................................................................... 4 Table 2 – Flooding Sources Studied by Detailed Methods for this FIS........................................ 4 Table 3 – Letters of Map Change................................................................................................... 6 Table 4 – Summary of Discharges.................................................................................................14 Table 5 – Summary of Stillwater Elevations.............................................................................. 20 Table 6 – Summary of Roughness Coefficients.......................................................................... 24 Table 7 – Floodway Data Table................................................................................................... 28 Table 8 – Community Map History.............................................................................................. 58 TABLE OF CONTENTS – VOLUME 2 EXHIBITS Exhibit 1 - Flood Profiles Allen Creek Panels 01P-03P Ashippun River Panels 04P-05P Bark River Panels 06P-19P Battle Creek Panel 20P Carriage Hill Drive Tributary Panels 21P-22P Carriage Hill Drive Tributary – Diversion Structure Panel 23P Carriage Hill Drive Tributary – Overland Flowpath Panel 24P Crawfish River Panels 25P-32P Galloway Creek Panels 33P-34P Johnson Creek Panels 35P-36P Koshkonong Creek Panels 37P-42P Maunesha River Panels 43P-45P Oconomowoc River Panels 46P-49P Rock Creek Panels 50P-55P Rock River Panels 56P–104P Scuppernong River Panels 105P-108P South Branch Panels 109P-110P South Branch Tributary Panel 111P Spring Creek Panels 112P-113P Tributary to Galloway Creek Panels 114P-115P Tributary to Whitewater Creek Panels 116P-118P Unnamed Tributary to Johnson Creek Panels 119P-120P Unnamed Tributary to Koshkonong Creek Panel 121P ii TABLE OF CONTENTS – VOLUME 2 (continued) EXHIBITS (continued) Whitewater Creek Panels 122P-127P Exhibit 2 - Flood Insurance Rate Map Index Flood Insurance Rate Map iii FLOOD INSURANCE STUDY JEFFERSON COUNTY, WISCONSIN AND INCORPORATED AREAS 1.0 INTRODUCTION 1.1 Purpose of Study This countywide Flood Insurance Study (FIS) revises and updates information on the existence and severity of flood hazards in the geographic area of Jefferson County, Wisconsin, including: the Cities of Fort Atkinson, Jefferson, Lake Mills, Waterloo, Watertown and Whitewater; the Villages of Cambridge, Johnson Creek, Lac La Belle, Palmyra and Sullivan, and the unincorporated areas of Jefferson County (hereinafter referred to collectively as Jefferson County). Please note that the City of Watertown is geographically located in Dodge and Jefferson Counties; the City of Whitewater is geographically located in Jefferson and Walworth Counties, Village of Cambridge is geographically located in Dane and Jefferson Counties; and the Village of Lac La Belle is geographically located in Jefferson and Waukesha counties; only the portion of these cities within Jefferson County are shown in this FIS. This FIS aids in the administration of the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973. This FIS has developed flood risk data for various areas of the county that will be used to establish actuarial flood insurance rates. This information will also be used by Jefferson County to update existing floodplain regulations as part of the Regular Phase of the National Flood Insurance Program (NFIP), and will also be used by local and regional planners to further promote sound land use and floodplain development. Minimum floodplain management requirements for participation in the NFIP are set forth in the Code of Federal Regulations at 44 CFR, 60.3. In some States or communities, floodplain management criteria or regulations may exist that are more restrictive or comprehensive than the minimum Federal requirements. In such cases, the more restrictive criteria take precedence and the State or other jurisdictional agency will be able to explain them. 1.2 Authority and Acknowledgments The sources of authority for this FIS are the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973. This FIS was prepared to include the unincorporated areas of, and incorporated communities within, Jefferson County in a countywide format. Information on the authority and acknowledgments for each jurisdiction included in this countywide FIS, as compiled from their previously printed FIS reports, is shown below. Fort Atkinson, City of: The hydrologic and hydraulic analyses for this study were obtained from the State of Wisconsin Department of Natural Resources (WDNR) (Reference 1). 1 Jefferson, City of: The hydrologic and hydraulic analyses for this study were obtained from WDNR (Reference 2). Johnson Creek, Village of: The hydrologic and hydraulic analyses for this study were performed by Donohue & Associates, Inc., for the Federal Emergency Management Agency (FEMA), under Contract No. EMW-C- 0287. This study, completed in April 1981, include all significant flooding sources affecting the Village of Johnson Creek (Reference 3). Palmyra, Village of: The hydrologic and hydraulic analyses for this study were performed by the U.S. Geological Survey (USGS) for FEMA, under Inter-agency Agreement No. EMW-85-E-1823, Project Order No. 14. This study was completed in July 1987. (Reference 4) Watertown, City of: The hydrologic and hydraulic analyses for this study were prepared by the USGS for the Federal Insurance Administration (FIA) under Inter- Agency Agreement No. IAA-H-9-77, Project Order No. 25; that work was completed in February 1979, and revised by the USGS, Madison, Wisconsin; this work was completed October 27, 1993 (Reference 5). Jefferson County: The hydrologic and hydraulic for this study were Unincorporated Areas prepared by the USGS for FEMA under Inter- Agency Agreement Nos. IAA-H-3-73 and IAA- H-20-74, Project Nos. 1 and 10, respectively. The study was completed in June 1974 and covered all significant flooding sources affecting the unincorporated areas of Jefferson County (Reference 6). For the original countywide FIS in 2009, redelineation of SFHAs was performed by Camp Dresser & McKee Federal Programs (CDM), under contract HSFE05-05- D-0027. This work was completed on July 28, 2006. On selected FIRM panels, planimetric base map information was provided in digital format. Information was provided by Jefferson County, as well as the WDNR. Additional information may have been derived from other sources. Users of this FIRM should be aware that minor adjustments may have been made to specific base map features. This countywide FIS includes new hydrologic and hydraulic analyses for Allen Creek, Ashippun River, Bark River, Battle Creek, Carriage Hill Drive Tributary, Carriage Hill Drive Tributary – Diversion Structure, Carriage Hill Drive Tributary – Overland Flowpath, Crawfish River, Galloway Creek, Johnson Creek, Koshkonong Creek,