Mchenry County Natural Hazards Mitigation Plan
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McHenry County Natural Hazards Mitigation Plan McHenry County Hazard Mitigation Planning Committee December 2010 Planning Assistance Provided By: McHenry County, Illinois Natural Hazards Mitigation Plan McHenry County Alden Township Village of Algonquin Algonquin Township Village of Bull Valley Burton Township Village of Cary Chemung Township City of Crystal Lake Coral Township Village of Fox River Grove Dorr Township Village of Greenwood Dunham Township City of Harvard Grafton Township Village of Hebron Greenwood Township Village of Holiday Hills Hartland Township Village of Huntley Hebron Township Village of Johnsburg Marengo Township Village of Lake in the Hills McHenry Township Village of Lakewood McHenry Township Road District Village of McCullom Lake McHenry Township Fire Protection Village of City of McHenry District City of Marengo Nunda Township Village of Oakwood Hills Richmond Township Village of Prairie Grove Riley Township Village of Richmond Seneca Township Village of Ringwood Woodstock Fire Rescue Village of Spring Grove Village of Trout Valley Village of Union Village of Wonder Lake City of Woodstock McHenry County Hazard Mitigation Planning Committee December 2010 This Natural Hazards Mitigation Plan was prepared with the plan development and technical support of Molly O’Toole & Associates, Ltd., 450 S. Stewart Avenue, Lombard, IL 60148, www.mollyotoole.com, and technical support of Johnson, Depp & Quisenberry, 6450 S. 6th Street, Suite B, Springfield, IL 62712, www.jdq-engineers.com. McHenry County Natural Hazards Mitigation Plan McHenry County Natural Hazards Mitigation Plan December 2010 Table of Contents Page Number: Executive Summary ES-1 Chapter 1. Introduction 1-1 1.1 Purpose of This Plan 1-2 1.2 Planning Approach 1-3 1.3 McHenry County Overview 1-8 1.4 McHenry County Land Use & Development 1-18 1.5 McHenry County Critical Facilities 1-19 Chapter 2. Natural Hazard Risk Assessment 2-1 2.1 Natural Hazards in McHenry County 2-1 2.2 McHenry County Assets and Property Value 2-3 2.3 Flood 2-10 2.4 Severe Summer Storms 2-20 2.5 Severe Winter Storms and Extreme Cold 2-29 2.6 Tornado 2-36 2.7 Extreme Heat 2-44 2.8 Drought 2-48 2.9 Earthquake 2-52 2.10 Dam Failure 2-58 2.11 Summary of Natural Hazards 2-63 2.12 References 2-66 Chapter 3. Goals 3-1 3.1 Consideration of Community Priorities 3-1 3.2 Plan Focus 3-2 3.3 Goals and Guidelines 3-3 3.4 Consistency with Other County and Municipal Planning 3-4 Chapter 4. Preventive Measures 4-1 4.1 Building Codes 4-1 4.2 Manufactured Home Installation 4-4 iii December 2010 McHenry County Natural Hazards Mitigation Plan Page 4.3 Critical Facility Construction 4-5 4.4 Planning and Zoning 4-7 4.5 Subdivision Regulations 4-10 4.6 Comprehensive Stormwater Management 4-10 4.7 Conclusions 4-19 4.8 Recommendations 4-20 4.9 References Chapter 5. Property Protection 5-1 5.1 Barriers, Elevation, Relocation, and Acquisition 5-1 5.2 Retrofitting – Modify the Building 5-5 5.3 Insurance 5-10 5.4 The Government’s Role 5-12 5.5 Repetitive Flood Loss Properties 5-14 5.6 Conclusions 5-17 5.7 Recommendations 5-18 5.8 References 5-19 Chapter 6. Structural Projects 6-1 6.1 Reservoirs and Detention 6-2 6.2 Levees and Barriers 6-4 6.3 Channel Improvements and Divers 6-5 6.4 Crossings and Roadways 6-6 6.5 Drainage and Storm Sewer Improvements 6-7 6.6 Drainage System Maintenance 6-9 6.7 Conclusions 6-11 6.8 Recommendations 6-12 6.9 References 6-13 Chapter 7. Resource Protection 7-1 7.1 Wetlands 7-2 7.2 Groundwater Protection 7-3 7.3 Stream Restoration 7-4 7.4 Dumping Regulations 7-7 7.5 Urban Forestry 7-9 7.6 Open Space Preservation 7-10 7.7 Farmland Protection 7-10 7.8 Historic and Natural Area Protection 7-11 7.9 Conclusions 7-12 iv December 2010 McHenry County Natural Hazards Mitigation Plan Page 7.10 Recommendations 7-13 7.11 References 7-14 Chapter 8. Emergency Services 8-1 8.1 Preparedness and Planning 8-1 8.2 Preparedness - Threat Recognition 8-2 8.3 Warning 8-6 8.4 Response 8-8 8.5 Critical Facilities Protection 8-9 8.6 Recovery and Mitigation 8-10 8.7 Conclusions 8-12 8.8 Recommendations 8-13 8.9 References 8-14 Chapter 9. Public Information 9-1 9.1 Outreach Projects 9-1 9.2 Library and Web Sites 9-3 9.3 Technical Assistance 9-4 9.4 Real Estate Disclosure 9-5 9.5 Public Information Program Strategy 9-7 9.6 Conclusions 9-8 9.7 Recommendations 9-8 9.8 References 9-9 Chapter 10. Action Plan 10-1 10.1 Action Plan Overview 10-1 10.2 Mitigation Action Items 10-2 10.3 Summary of Action Plan Items 10-15 10.4 Plan Implementation and Maintenance 10-16 Appendices [Not Printed] Appendix A. McHenry County Hazard Mitigation Planning Committee Participation Appendix B. Example Public Involvement Information Appendix C. McHenry County NCDC Recorded Storm Data Appendix D. McHenry County Critical Facility Information [Confidential – Not Printed] Appendix E. County, Municipal and Township Action Items v December 2010 McHenry County Natural Hazards Mitigation Plan List of Tables Page Table 1-1 McHenry County Hazard Mitigation Planning Participants 1-5 Table 1-2 McHenry County Township Population Data 1-12 Table 1-3 McHenry County Municipal Data 1-13 Table 1-4 McHenry County Major Employers 1-17 Table 1-5 McHenry County Existing Land Use 1-18 Table 1-6 McHenry County Future Land Use 1-18 Table 1-7 McHenry County Summary of Critical Facilities 1-20 Table 2-1 State and Federal Disaster Declarations for McHenry County 2-1 Table 2-2 McHenry County Identified and Potential Hazards 2-2 Table 2-3 McHenry County Mitigation Committee Ranking of Identified and 2-3 Potential Hazards Table 2-4 McHenry County Estimate of Assets 2-4 Table 2-5 McHenry Non-Exempt, Non-Farm Building Values 2-5 Table 2-6 McHenry County Municipal Populations - Ranked 2-6 Table 2-7 McHenry County Housing Density by Township - Ranked 2-7 Table 2-8 McHenry All Non-Exempt Building Values 2-8 Table 2-9 McHenry County Average Building Values 2-9 Table 2-10 McHenry County Watersheds 2-11 Table 2-11 Reported Flood Events in McHenry County 2-19 Table 2-12 Summary of McHenry County Community Flood Insurance Claims 2-17 Information Table 2-13 McHenry County Repetitive Loss Structures 2-18 Table 2-14 Hail Size Descriptions 2-22 Table 2-15 Lightning Events Reported in McHenry County 1996 through August 2-27 31, 2009 Table 2-16 Severe Winter Storm & Extreme Cold Events Reported in McHenry 2-33 County 1994 through August 31, 2009 Table 2-17 Vehicle Crashes During Winter 2-35 Table 2-18 Tornadoes Reported in McHenry County 1958 through August 31, 2-38 2009 Table 2-19 Extreme Heat Events Reported in McHenry County 1995 through 2-47 August 31, 2009 Table 2-20 Probability of Earthquake Events in The New Madrid Seismic Zone 2-57 Table 2-21 Classified Dams with McHenry County 2-60 Table 2-22 Summary of McHenry County Natural Hazards 2-64 Table 2-23 McHenry County Hazard Identification by Community and Township 2-65 for Natural Hazards Table 2-24 IEMA Hazard Ratings for McHenry County 2-66 Table 4-1 Building Codes Used in McHenry County and BCEGS Ratings 4-3 Table 4-2 McHenry County Planning and Land Use Ordinances 4-9 vi December 2010 McHenry County Natural Hazards Mitigation Plan Page Table 4-3 McHenry Countywide Stormwater Ordinance – Certified Community 4-17 Status Table 5-1 Reported Types of Existing Flood Problems in McHenry County 5-2 Table 5-2 Identified McHenry County Repetitive Flood Loss Areas 5-17 Table 6-1 McHenry County Bridges and Roadways That Potentially Impede Flood 6-7 Flows Table 6-2 McHenry County Municipal Drainage System Maintenance 6-10 Table 6-3 McHenry County Township Drainage System Maintenance 6-11 Table 7-1 McHenry County Communities that Prohibit Dumping in Streams 7-8 Table 7-2 McHenry County Tree City USA Communities 7-9 Table 7-3 National Register of Historic Places in McHenry County 7-12 Table 8-1 Flood Forecast and Rain and Stream Gage Links 8-3 Table 8-2 McHenry County Rain and Stream Gages 8-4 Table 8-3 Community Emergency Flood Procedures 8-11 Table 9-1 McHenry County Communities Providing Technical Assistance to 9-5 Property Owners Table 10-1 Action Items, Responsible Agencies and Deadlines 10-17 Table 10-2 Action Items, Goals and Guidelines 10-18 Table 10-3 Action Items and Recommendations 10-19 List of Exhibits (Maps) Page Exhibit 1-1 McHenry County Base Map 1-9 Exhibit 1-2 McHenry County Watersheds 1-11 Exhibit 1-3 McHenry County School Districts 1-14 Exhibit 1-4 McHenry County Fire Districts 1-15 Exhibit 1-5 Locations of McHenry County Critical Facilities 1-21 Exhibit 2-1 Recorded McHenry County Wind Events 2-24 Exhibit 2-2 Recorded McHenry County Hail Events 2-26 Exhibit 2-3 Recorded McHenry County Tornado Events 2-39 Exhibit 5-1 McHenry County Repetitive Flood Loss Areas 5-16 Exhibit 6-1 Past Flooding Locations on McHenry County Highways (1980 to 6-8 2010) Exhibit 7-1 McHenry County Sensitive Aquifer Recharge Areas 7-5 Exhibit 8-1 McHenry County Rain and Stream Gage Locations 8-5 vii December 2010 McHenry County Natural Hazards Mitigation Plan List of Figures Page Figure 1-1 McHenry County Employment 1-16 Figure 2-1 McHenry County Flood & Flash Flood Events by Month 1982 through 2-14 8/31/2009 Figure 2-2 McHenry County Flood & Flash Flood Events by Hour 1982 through 2-14 8/31/2009 Figure 2-3 McHenry County Thunderstorm & High Wind Events by Month – 1960 2-23 through 8/31/2009 Figure 2-4 McHenry County Thunderstorm & High Wind Events by Hour – 1960 2-23 through 8/31/2009 Figure 2-5 McHenry County Hail Events by Month 1973 through 8/31/2009 2-25 Figure 2-6 McHenry County Hail Events by Hour 1973 through 8/31/2009 2-25 Figure 2-7 McHenry County Severe Winter Storm & Extreme Cold Events by 2-34 Month 1994 through 8/31/2009 Figure 2-8 McHenry County Severe Winter Storm & Extreme Cold Events by Hour 2-34 1994 through 8/31/2009 Figure 2-9 McHenry County Tornadoes by Month 1958 through 8/31/2009 2-40 Figure 2-10 McHenry County Tornadoes by Hour 1958 through 8/31/2009 2-40 Figure 2-11 Drought Severity Index by Division 2-49 Figure 2-12 U.S.