VOLUME 7 OF 7 NORFOLK COUNTY, MASSACHUSETTS (ALL JURISDICTIONS)
COMMUNITY NAME NUMBER COMMUNITY NAME NUMBER AVON, TOWN OF 250231 MILTON, TOWN OF 250245 BELLINGHAM, TOWN OF 250232 NEEDHAM, TOWN OF 255215 BRAINTREE, TOWN OF 250233 NORFOLK, TOWN OF 255217 BROOKLINE, TOWN OF 250234 NORWOOD, TOWN OF 250248 CANTON, TOWN OF 250235 PLAINVILLE, TOWN OF 250249 COHASSET, TOWN OF 250236 QUINCY, CITY OF 255219 DEDHAM, TOWN OF 250237 RANDOLPH, TOWN OF 250251 DOVER, TOWN OF 250238 SHARON, TOWN OF 250252 FOXBOROUGH, TOWN OF 250239 STOUGHTON, TOWN OF 250253 FRANKLIN, TOWN OF 250240 WALPOLE, TOWN OF 250254 HOLBROOK, TOWN OF 255212 WELLESLEY, TOWN OF 250255 MEDFIELD, TOWN OF 250242 WESTWOOD, TOWN OF 255225 MEDWAY, TOWN OF 250243 WEYMOUTH, TOWN OF 250257 MILLIS, TOWN OF 250244 WRENTHAM, TOWN OF 250258
REVISED: PRELIMINARY 06/19/2020
FLOOD INSURANCE STUDY NUMBER 25021CV007D
Version Number 2.6.3.6
TABLE OF CONTENTS Volume 1 Page
SECTION 1.0 – INTRODUCTION 1 1.1 The National Flood Insurance Program 1 1.2 Purpose of this Flood Insurance Study Report 2 1.3 Jurisdictions Included in the Flood Insurance Study Project 2 1.4 Considerations for using this Flood Insurance Study Report 4
SECTION 2.0 – FLOODPLAIN MANAGEMENT APPLICATIONS 15 2.1 Floodplain Boundaries 15 2.2 Floodways 36 2.3 Base Flood Elevations 37 2.4 Non-Encroachment Zones 37 2.5 Coastal Flood Hazard Areas 37 2.5.1 Water Elevations and the Effects of Waves 37 2.5.2 Floodplain Boundaries and BFEs for Coastal Areas 39 2.5.3 Coastal High Hazard Areas 40 2.5.4 Limit of Moderate Wave Action 41
SECTION 3.0 – INSURANCE APPLICATIONS 42 3.1 National Flood Insurance Program Insurance Zones 42
SECTION 4.0 – AREA STUDIED 43 4.1 Basin Description 43 4.2 Principal Flood Problems 44 4.3 Non-Levee Flood Protection Measures 46 4.4 Levees 54
SECTION 5.0 – ENGINEERING METHODS 59 5.1 Hydrologic Analyses 59 5.2 Hydraulic Analyses 86
Figures Page
Figure 1: FIRM Panel Index 7 Figure 2: FIRM Notes to Users 8 Figure 3: Map Legend for FIRM 11 Figure 4: Floodway Schematic 36 Figure 5: Wave Runup Transect Schematic 39 Figure 6: Coastal Transect Schematic 41 Figure 7: Frequency Discharge-Drainage Area Curves 84
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Tables Page
Table 1: Listing of NFIP Jurisdictions 2 Table 2: Flooding Sources Included in this FIS Report 16 Table 3: Flood Zone Designations by Community 42 Table 4: Basin Characteristics 43 Table 5: Principal Flood Problems 44 Table 6: Historic Flooding Elevations 46 Table 7: Non-Levee Flood Protection Measures 54 Table 8: Levees 58 Table 9: Summary of Discharges 60 Table 10: Summary of Non-Coastal Stillwater Elevations 85 Table 11: Stream Gage Information used to Determine Discharges 86 Table 12: Summary of Hydrologic and Hydraulic Analyses 88
Volume 2 Page
5.3 Coastal Analyses 186
Tables Page
Table 13: Roughness Coefficients 179 Table 14: Summary of Coastal Analyses 186
Volume 3 Page
5.3.1 Total Stillwater Elevations 188 5.3.2 Waves 190 5.3.3 Coastal Erosion 190 5.3.4 Wave Hazard Analyses 190 5.4 Alluvial Fan Analyses 197
SECTION 6.0 – MAPPING METHODS 197 6.1 Vertical and Horizontal Control 197 6.2 Base Map 198 6.3 Floodplain and Floodway Delineation 199
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Figures Page
Figure 8: 1% Annual Chance Total Stillwater Elevations for Coastal Areas 189 Figure 9: Transect Location Map 196
Tables Page
Table 15: Tide Gage Analysis Specifics 189 Table 16: Coastal Transect Parameters 191 Table 17: Summary of Alluvial Fan Analyses 197 Table 18: Results of Alluvial Fan Analyses 197 Table 19: Countywide Vertical Datum Conversion 198 Table 20: Stream-Based Vertical Datum Conversion 198 Table 21: Base Map Sources 198 Table 22: Summary of Topographic Elevation Data used in Mapping 200 Table 23: Floodway Data 203
Volume 4 Page
6.4 Coastal Flood Hazard Mapping 316 6.5 FIRM Revisions 320 6.5.1 Letters of Map Amendment 320 6.5.2 Letters of Map Revision Based on Fill 320 6.5.3 Letters of Map Revision 321 6.5.4 Physical Map Revisions 323 6.5.5 Contracted Restudies 323 6.5.6 Community Map History 323
SECTION 7.0 – CONTRACTED STUDIES AND COMMUNITY COORDINATION 327 7.1 Contracted Studies 327 7.2 Community Meetings 344
SECTION 8.0 – ADDITIONAL INFORMATION 351
SECTION 9.0 – BIBLIOGRAPHY AND REFERENCES 353
Tables Page
Table 24: Flood Hazard and Non-Encroachment Data for Selected Streams 316 Table 25: Summary of Coastal Transect Mapping Considerations 317 Table 26: Incorporated Letters of Map Change 321
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Table 27: Community Map History 324 Table 28: Summary of Contracted Studies Included in this FIS Report 327 Table 29: Community Meetings 345 Table 30: Map Repositories 351 Table 31: Additional Information 352 Table 32: Bibliography and References 354
Volume 5 Exhibits
Flood Profiles Panel Arnolds Brook 001 P Beaver Brook (Town of Avon) 002-003 P Beaver Brook (Town of Bellingham) 004-005 P Beaver Brook (Town of Holbrook) 006-007 P Beaver Brook (Town of Sharon) 008 P Beaver Meadow Brook 009 P Billings Brook 010 P Billings Brook Branch 011 P Bogastow Brook 012-017 P Brook A (Stetson Brook) 018 P Brook B 019 P Brook No. 1 020-021 P Bubbling Brook 022-024 P Buckmaster Brook 025 P Bungay Brook 026-027 P Burnt Swamp Brook 028-029 P Canoe River (Town of Foxborough) 030-031 P Canoe River (Town of Sharon) 032 P Canton River 033-035 P Caroline Brook 036 P Charles River 037 P Charles River (Lower Reach) 038-047 P Charles River (Upper Reach) 048-060 P Chicken Brook 061-064 P Cobb’s Brook 065-066 P Cochato River/Trout Brook 067-072 P Cress Brook 073-074 P Crocker Brook 075 P Cunningham Brook 076 P Diamond Brook 077-078 P Dorchester Brook 079 P Farm River 080-082 P Fuller Brook 083 P Furnace Brook 084-086 P Germany Brook 087-089 P Glovers Brook 090-091 P Harlow Pond Lateral 092 P
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Volume 6 Exhibits
Flood Profiles Panel Hawes Brook 093-094 P Hawthorne Brook 095 P Herring Brook 096 P Hopping Brook 097-098 P James Brook 099 P Lily Pond Stream 100 P Mann Pond Lateral 101 P Martin Brook 102-103 P Mary Lee Brook 104 P Massapoag Brook (Town of Canton) 105-106 P Massapoag Brook (Town of Sharon) 107-108 P Meadow Brook 109 P Mill Brook 110-112 P Mill River (Town of Norfolk) 113-114 P Mill River (Town of Weymouth) 115-116 P Mill River Tributary A 117 P Mill River Tributary B 118 P Miller Brook 119 P Mine Brook (Town of Franklin) 120-128 P Mine Brook (Town of Walpole) 129-130 P Monatiquot River 131-136 P Mother Brook 137-139 P Myrtle Street Lateral 140 P Neponset River 141-160 P Norroway Brook 161-162 P Old Swamp River 163-165 P Pequid Brook (Lower Reach) 166 P Pequid Brook (Upper Reach) 167 P Peters River 168-172 P Pickerel Brook 173 P Pine Tree Brook 174-176 P Plantingfield Brook 177-178 P Ponkapoag Brook 179-181 P Prison Farm Lateral 182-183 P
Volume 7 Exhibits
Flood Profiles Panel Purgatory Brook 184-187 P Rabbit Hill Brook 188-189 P Rattlesnake Run 190 P Redwing Brook 191 P Richardsons Brook 192 P Robinson Brook 193-195 P
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Rock Meadow Brook 196-199 P Rocky Brook 200 P Rumford River 201-202 P School Meadow Brook 203-204 P Sevenmile River 205 P Shepards Brook 206 P South Brook 207 P Steep Hill Brook 208-209 P Stony Brook 210-212 P Stop River 213-217 P Sucker Brook 218 P Ten Mile River 219-220 P Town Brook 221-225 P Traphole Brook 226-227 P Tributary C2B 228 P Tributary R2 229 P Tributary R3 230 P Tributary R4 231 P Tributary to Great Black Swamp 232 P Tributary to Steep Hill Brook 233 P Trout Brook (Town of Avon) 234 P Trout Brook (Town of Dover) 235-237 P Turkey Hill Run 238 P Turtle Brook 239-240 P Unnamed Tributary to Mary Lee Brook 241 P Unnamed Tributary to Robinson Brook 242 P Vine Brook 243-244 P Waban Brook 245 P Wading River 246 P Walnut Hill Stream 247 P Whiting Pond Bypass 248-249 P
Published Separately
Flood Insurance Rate Map (FIRM)
vi 184P 185P 186P 187P 188P 189P 35 35
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295 295 LEGEND
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285 50,800 50,900 51,000 51,100 51,200 51,300 51,400 51,500 51,600 FEDERAL EMERGENCY MANAGEMENT AGENCY MANAGEMENT EMERGENCY FEDERAL STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH TEN MILE RIVER 205P 206P 207P 208P 209P 210P 211P 212P 213P HIGHLAND LAKE
214P 215P 216P 217P 218P DAM DAM BRIDGE CULVERT FOOTBRIDGE COUNTYLIMIT BACONSQUARE WITHERELLPLACE WESTBACON STREET TEN MILE RIVER TELFORD FOOTBRIDGEPARK FLOOD PROFILES
210 210 ELEVATION IN FEET (NAVD) ELEVATION
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190 190 LEGEND
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FQ FX 2% ANNUAL CHANCE FLOOD 180 10% ANNUAL CHANCE FLOOD (ALL (ALL JURISDICTIONS) FP FT FW FZ GB GD STREAM BED
FM FN FO FR FS FU FV FY GA GC CROSS SECTION MA NORFOLK COUNTY, LOCATION
108,000 108,500 109,000 109,500 110,000 110,500 111,000 111,500 112,000 112,500 113,000 113,500 114,000 114,500 FEDERAL EMERGENCY MANAGEMENT AGENCY MANAGEMENT EMERGENCY FEDERAL
DISTANCE IN FEET ABOVE CONFLUENCE WITH SEEKONK RIVER 219P BRIDGE CULVERT CULVERT CULVERT HIGHSTREET
240 FULLERSTREET 240 LIMIT LIMIT OFDETAILED STUDY TEN MILE RIVER FLOOD PROFILES
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220 220 ELEVATION IN FEET (NAVD) ELEVATION
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GG GJ GK GM GN GP GQ GR GS GT GU GV CROSS SECTION MA NORFOLK COUNTY, LOCATION
114,500 115,000 115,500 116,000 116,500 117,000 117,500 118,000 118,500 119,000 119,500 120,000 120,500 FEDERAL EMERGENCY MANAGEMENT AGENCY MANAGEMENT EMERGENCY FEDERAL
DISTANCE IN FEET ABOVE CONFLUENCE WITH SEEKONK RIVER 220P
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233P 234P 235P 236P 237P 238P 239P 240P 241P 295 295
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160 160 ELEVATION IN FEET (NAVD) ELEVATION
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CQ CR CS CT CROSS SECTION MA NORFOLK COUNTY, LOCATION
62,700 62,900 63,100 63,300 63,500 63,700 63,900 64,100 64,300 64,500 64,700 64,900 65,100 65,300 FEDERAL EMERGENCY MANAGEMENT AGENCY MANAGEMENT EMERGENCY FEDERAL
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH THREE MILE RIVER 246P 35 35 1% BACKWATER EFFECT FROM THE GULF
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F STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH THE GULF 247P FLOOD PROFILES WHITING POND BYPASS COUNTYLIMIT
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190 190 ELEVATION IN FEET (NAVD) ELEVATION
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2,100 2,200 2,300 2,400 2,500 2,600 2,700 2,800 2,900 3,000 3,100 3,200 3,300 3,400 FEDERAL EMERGENCY MANAGEMENT AGENCY MANAGEMENT EMERGENCY FEDERAL
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH TEN MILE RIVER 248P RIVER BRIDGE WESTBACON STREET DIVERGENCE FROMTEN MILE FLOOD PROFILES WHITING POND BYPASS
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200 200 ELEVATION IN FEET (NAVD) ELEVATION
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3,400 3,600 3,800 4,000 4,200 4,400 4,600 4,800 5,000 5,200 5,400 5,600 5,800 6,000 FEDERAL EMERGENCY MANAGEMENT AGENCY MANAGEMENT EMERGENCY FEDERAL
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH TEN MILE RIVER 249P