Volume I of the Flood Insurance Study

Home , Presumpscot River, Stroudwater River

VOLUME 1 OF 4 CUMBERLAND COUNTY, MAINE (ALL JURISDICTIONS)

COMMUNITY NAME NUMBER COMMUNITY NAME NUMBER BALDWIN, TOWN OF 230200 POWNAL, TOWN OF 230204 BRIDGTON, TOWN OF 230041 RAYMOND, TOWN OF 230205 BRUNSWICK, TOWN OF 230042 SCARBOROUGH, TOWN OF 230052 CAPE ELIZABETH, TOWN OF 230043 SEBAGO, TOWN OF 230206 CASCO, TOWN OF 230044 SOUTH PORTLAND, CITY OF 230053 CHEBEAGUE ISLAND, TOWN OF 231037 STANDISH, TOWN OF 230207 CUMBERLAND, TOWN OF 230162 WESTBROOK, CITY OF 230054 FALMOUTH, TOWN OF 230045 WINDHAM, TOWN OF 230189 FREEPORT, TOWN OF 230046 YARMOUTH, TOWN OF 230055 FRYE ISLAND, TOWN OF 231036 GORHAM, TOWN OF 230047 GRAY, TOWN OF 230048 HARPSWELL, TOWN OF 230169 HARRISON, TOWN OF 230049 LONG ISLAND, TOWN OF 231035 NAPLES, TOWN OF 230050 NEW GLOUCESTER, TOWN OF 230201 NORTH YARMOUTH, TOWN OF 230202 PORTLAND, CITY OF 230051 EFFECTIVE:

FLOOD INSURANCE STUDY NUMBER 23005CV001A Version Number 2.3.2.1

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 18

SECTION 2.0 – FLOODPLAIN MANAGEMENT APPLICATIONS 28 2.1 Floodplain Boundaries 28 2.2 Floodways 39 2.3 Base Flood Elevations 40 2.4 Non-Encroachment Zones 40 2.5 Coastal Flood Hazard Areas 41 2.5.1 Water Elevations and the Effects of Waves 41 2.5.2 Floodplain Boundaries and BFEs for Coastal Areas 42 2.5.3 Coastal High Hazard Areas 43 2.5.4 Limit of Moderate Wave Action 44

SECTION 3.0 – INSURANCE APPLICATIONS 45 3.1 National Flood Insurance Program Insurance Zones 45 3.2 Coastal Barrier Resources System 46

SECTION 4.0 – AREA STUDIED 47 4.1 Basin Description 47 4.2 Principal Flood Problems 48 4.3 Non-Levee Flood Protection Measures 49 4.4 Levees 53

SECTION 5.0 – ENGINEERING METHODS 53 5.1 Hydrologic Analyses 53 5.2 Hydraulic Analyses 74 5.3 Coastal Analyses 94 5.3.1 Total Stillwater Elevations 98 5.3.2 Waves 99 5.3.3 Coastal Erosion 100 5.3.4 Wave Hazard Analyses 100 5.4 Alluvial Fan Analyses 112

TABLE OF CONTENTS - continued Volume 1 - continued

Figures Page

Figure 1: FIRM Index 20 Figure 2: FIRM Notes to Users 21 Figure 3: Map Legend for FIRM 24 Figure 4: Floodway Schematic 39 Figure 5: Wave Runup Transect Schematic 42 Figure 6: Coastal Transect Schematic 44 Figure 7: Frequency Discharge-Drainage Area Curves 72 Figure 8: 1% Annual Chance Total Stillwater Elevations for Coastal Areas 98 Figure 9: Transect Location Map 111

Tables Page

Table 1: Listing of NFIP Jurisdictions 2 Table 2: Flooding Sources Included in this FIS Report 30 Table 3: Flood Zone Designations by Community 46 Table 4: Coastal Barrier Resources System Information 47 Table 5: Basin Characteristics 48 Table 6: Principal Flood Problems 48 Table 7: Historic Flooding Elevations 49 Table 8: Non-Levee Flood Protection Measures 50 Table 9: Levees 53 Table 10: Summary of Discharges 60 Table 11: Summary of Non-Coastal Stillwater Elevations 72 Table 12: Stream Gage Information used to Determine Discharges 74 Table 13: Summary of Hydrologic and Hydraulic Analyses 81 Table 14: Roughness Coefficients 93 Table 15: Summary of Coastal Analyses 94 Table 16: Tide Gage Analysis Specifics 99 Table 17: Coastal Transect Parameters 102 Table 18: Summary of Alluvial Fan Analyses 112 Table 19: Results of Alluvial Fan Analyses 112

Volume 2 Page

SECTION 6.0 – MAPPING METHODS 113 6.1 Vertical and Horizontal Control 113 6.2 Base Map 114 6.3 Floodplain and Floodway Delineation 115 6.4 Coastal Flood Hazard Mapping 166

TABLE OF CONTENTS - continued Volume 2 - continued Page

6.5 FIRM Revisions 176 6.5.1 Letters of Map Amendment 176 6.5.2 Letters of Map Revision Based on Fill 177 6.5.3 Letters of Map Revision 177 6.5.4 Physical Map Revisions 178 6.5.5 Contracted Restudies 179 6.5.6 Community Map History 179

SECTION 7.0 – CONTRACTED STUDIES AND COMMUNITY COORDINATION 182 7.1 Contracted Studies 182 7.2 Community Meetings 190

SECTION 8.0 – ADDITIONAL INFORMATION 195

SECTION 9.0 – BIBLIOGRAPHY AND REFERENCES 198

Tables Page

Table 20: Countywide Vertical Datum Conversion 113 Table 21: Stream-Based Vertical Datum Conversion 114 Table 22: Base Map Sources 115 Table 23: Summary of Topographic Elevation Data used in Mapping 116 Table 24: Floodway Data 117 Table 25: Flood Hazard and Non-Encroachment Data for Selected Streams 166 Table 26: Summary of Coastal Transect Mapping Considerations 167 Table 27: Incorporated Letters of Map Change 178 Table 28: Community Map History 180 Table 29: Summary of Contracted Studies Included in this FIS Report 182 Table 30: Community Meetings 191 Table 31: Map Repositories 195 Table 32: Additional Information 197 Table 33: Bibliography and References 199

Volume 3 Exhibits

Flood Profiles Panel Androscoggin River 01-06 P Breakneck Brook 07-09 P Capisic Brook 10-12 P Clark Brook 13-14 P

iii

TABLE OF CONTENTS - continued Volume 3 – continued

Exhibits - continued

Flood Profiles Panel Collyer Brook 15-18 P Colley Wright Brook 19 P Corn Shop Brook 20 P Crooked River 21-25 P Crooked River (Town of Harrison) 26-28 P Crystal Lake Brook 29 P Ditch Brook 30-32 P Dug Hill Brook 33-34 P East Branch Capsic Brook 35 P Eddy Brook 36 P Fall Brook 37-39 P Hobbs Brook 40-41 P Long Creek and Jackson Brook 42 P Jackson Brook 43 P Milliken Brook 44 P Mill Brook 45-46 P Minnow Brook 47-49 P Nasons Brook 50 P North Branch Little River 51 P Pigeon Brook 52-53 P Pigeon Brook Tributary 54 P Piscataqua River 55-58 P Pleasant River 59-60 P Presumpscot River 61-70 P Quaker Brook 71 P Red Brook 72 P Royal River (Downstream) 73-74 P Royal River (Upstream) 75-83 P

Volume 4

Exhibits - continued

Flood Profiles Panel Saco River 84-94 P Saco River Left Channel 95 P Songo River 96-97 P Stevens Brook 98-99 P Stroudwater River 100-105 P Thayer Brook 106-107 P Tributary 1 to Presumpscot River 108 P Tributary 2 to Presumpscot River 109 P

TABLE OF CONTENTS - continued Volume 4 – continued

Exhibits - continued

Flood Profiles Panel Tributary A 110 P Tributary to Clark Brook 111 P Trout Brook 112-113 P Unnamed Tributary to Colley Wright Brook 114 P Unnamed Tributary to Presumpscot River 115 P Unnamed Tributary to Rich Mill Brook 116 P Unnamed Tributary to Tucker Brook 117 P Westcott Brook 118 P West Branch Capisic Brook 119 P Willet Brook 120 P

Published Separately

Flood Insurance Rate Map (FIRM)

FLOOD INSURANCE STUDY REPORT CUMBERLAND COUNTY, MAINE

SECTION 1.0 – INTRODUCTION

1.1 The National Flood Insurance Program The National Flood Insurance Program (NFIP) is a voluntary Federal program that enables property owners in participating communities to purchase insurance protection against losses from flooding. This insurance is designed to provide an alternative to disaster assistance to meet the escalating costs of repairing damage to buildings and their contents caused by floods.

For decades, the national response to flood disasters was generally limited to constructing flood-control works such as dams, levees, sea-walls, and the like, and providing disaster relief to flood victims. This approach did not reduce losses nor did it discourage unwise development. In some instances, it may have actually encouraged additional development. To compound the problem, the public generally could not buy flood coverage from insurance companies, and building techniques to reduce flood damage were often overlooked.

In the face of mounting flood losses and escalating costs of disaster relief to the general taxpayers, the U.S. Congress created the NFIP. The intent was to reduce future flood damage through community floodplain management ordinances, and provide protection for property owners against potential losses through an insurance mechanism that requires a premium to be paid for the protection.

The U.S. Congress established the NFIP on August 1, 1968, with the passage of the National Flood Insurance Act of 1968. The NFIP was broadened and modified with the passage of the Flood Disaster Protection Act of 1973 and other legislative measures. It was further modified by the National Flood Insurance Reform Act of 1994 and the Flood Insurance Reform Act of 2004. The NFIP is administered by the Federal Emergency Management Agency (FEMA), which is a component of the Department of Homeland Security (DHS).

Participation in the NFIP is based on an agreement between local communities and the Federal Government. If a community adopts and enforces floodplain management regulations to reduce future flood risks to new construction and substantially improved structures in Special Flood Hazard Areas (SFHAs), the Federal Government will make flood insurance available within the community as a financial protection against flood losses. The community’s floodplain management regulations must meet or exceed criteria established in accordance with Title 44 Code of Federal Regulations (CFR) Part 60, Criteria for Land Management and Use .

SFHAs are delineated on the community’s Flood Insurance Rate Maps (FIRMs). Under the NFIP, buildings that were built before the flood hazard was identified on the community’s FIRMs are generally referred to as “Pre-FIRM” buildings. When the NFIP was created, the U.S. Congress recognized that insurance for Pre-FIRM buildings would be prohibitively expensive if the premiums were not subsidized by the Federal

Government. Congress also recognized that most of these floodprone buildings were built by individuals who did not have sufficient knowledge of the flood hazard to make informed decisions. The NFIP requires that full actuarial rates reflecting the complete flood risk be charged on all buildings constructed or substantially improved on or after the effective date of the initial FIRM for the community or after December 31, 1974, whichever is later. These buildings are generally referred to as “Post-FIRM” buildings.

1.2 Purpose of this Flood Insurance Study Report This Flood Insurance Study (FIS) Report revises and updates information on the existence and severity of flood hazards for the study area. The studies described in this report developed flood hazard data that will be used to establish actuarial flood insurance rates and to assist communities in efforts to implement sound floodplain management.

In some states or communities, floodplain management criteria or regulations may exist that are more restrictive than the minimum Federal requirements. Contact your State NFIP Coordinator to ensure that any higher State standards are included in the community’s regulations.

1.3 Jurisdictions Included in the Flood Insurance Study Project This FIS Report covers the entire geographic area of Cumberland County, Maine.

The jurisdictions that are included in this project area, along with the Community Identification Number (CID) for each community and the United States Geological Survey (USGS) 8-digit Hydrologic Unit Code (HUC-8) sub-basins affecting each, are shown in Table 1. The FIRM panel numbers that affect each community are listed. If the flood hazard data for the community is not included in this FIS Report, the location of that data is identified.

The location of flood hazard data for participating communities in multiple jurisdictions is also indicated in the table.

Table 1: Listing of NFIP Jurisdictions If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0195F 23005C0213F 23005C0406F

01060001 23005C0407F Baldwin, Town of 230200 01060002 23005C0408F 23005C0409F 23005C0416F 23005C0417F

2 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0426F 23005C0427F 23005C0428F¹ 23005C0429F¹ 23005C0431F¹ 01060001 23005C0432F Baldwin, Town of - continued 230200 01060002 23005C0433F 23005C0434F 23005C0436F 23005C0437F 23005C0441F 23005C0442F 23005C0015F¹ 23005C0055F 23005C0056F¹ 23005C0057F 23005C0058F 23005C0059F 23005C0065F 23005C0070F 23005C0076F 23005C0077F 23005C0078F 23005C0079F 23005C0081F 01060001 Bridgton, Town of 230041 23005C0083F 01060002 23005C0086F 23005C0087F 23005C0090F 23005C0091F 23005C0092F 23005C0093F 23005C0094F 23005C0185F¹ 23005C0203F 23005C0204F 23005C0205F 23005C0206F 23005C0208F

1 Panel Not Printed

3 Table 1: Listing of NFIP Jurisdictions • continued

If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0330F¹ 23005C0331F 23005C0333F 23005C0334F 23005C0340F 23005C0346F 23005C0347F 23005C0348F 23005C0349F 23005C0359F 23005C0361F 23005C0362F 23005C0363F 23005C0364F 23005C0366F 01040002 23005C0367F Brunswick, Town of 230042 01060001 23005C0368F 23005C0369F 23005C0378F 23005C0386F 23005C0388F 23005C0556F 23005C0557F 23005C0558F 23005C0559F 23005C0576F 23005C0577F 23005C0578F 23005C0579F 23005C0581F 23005C0582F 23005C0583F

23005C0713F 23005C0714F Cape Elizabeth, Town of 230043 01060001 23005C0807F 23005C0809F 23005C0817F

1 Panel Not Printed

4 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0826F 23005C0827F Cape Elizabeth, Town of - 23005C0828F 230043 01060001 continued 23005C0829F 23005C0836F 23005C0837F 23005C0117F 23005C0118F 23005C0119F 23005C0136F 23005C0138F 23005C0139F 23005C0227F 23005C0229F 23005C0231F 23005C0232F 23005C0233F 01040002 Casco, Town of 230044 23005C0234F 01060001 23005C0237F 23005C0239F¹ 23005C0241F 23005C0242F 23005C0243F 23005C0244F 23005C0251F 23005C0252F 23005C0253F 23005C0261F 23005C0456F 23005C0544F 23005C0563F 23005C0564F 23005C0706F Chebeague Island, Town of 231037 01060001 23005C0707F 23005C0708F 23005C0709F 23005C0726F 23005C0727F

1 Panel Not Printed

5 Table 1: Listing of NFIP Jurisdictions • continued

If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0728F 23005C0729F Chebeague Island, Town of - 231037 01060001 23005C0733F continued 23005C0736F 23005C0737F 23005C0504F 23005C0506F 23005C0508F 23005C0509F 23005C0512F 23005C0516F 23005C0517F 23005C0518F 23005C0519F Cumberland, Town of 230162 01060001 23005C0536F 23005C0537F 23005C0538F 23005C0539F 23005C0543F 23005C0701F 23005C0702F 23005C0706F 23005C0707F

23005C0511F 23005C0512F 23005C0513F 23005C0514F 23005C0516F 23005C0518F 23005C0519F 23005C0538F Falmouth, Town of 230045 01060001 23005C0676F 23005C0677F 23005C0681F 23005C0682F 23005C0683F 23005C0684F 23005C0701F 23005C0702F

6 Table 1: Listing of NFIP Jurisdictions • continued

If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0703F 23005C0704F Falmouth, Town of - 23005C0706F 230045 01060001 continued 23005C0708F 23005C0711F 23005C0712F

23005C0320F 23005C0340F 23005C0348F 23005C0531F 23005C0532F 23005C0533F 23005C0534F 23005C0542F 23005C0551F 23005C0552F 01040002 Freeport, Town of 230046 23005C0553F 01060001 23005C0554F 23005C0556F 23005C0557F 23005C0558F 23005C0559F 23005C0561F 23005C0562F 23005C0564F 23005C0566F 23005C0568F

23005C0456F 23005C0457F Frye Island, Town of 231036 01060001 23005C0458F 23005C0459F

23005C0469F 23005C0479F 23005C0486F 23005C0487F Gorham, Town of 230047 01060001 23005C0488F 23005C0489F 23005C0631F 23005C0632F

7 Table 1: Listing of NFIP Jurisdictions • continued

If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0633F 23005C0634F 23005C0642F 23005C0651F 23005C0652F 23005C0653F 23005C0654F 23005C0656F 23005C0658F 23005C0659F Gorham, Town of - continued 230047 01060001 23005C0661F 23005C0662F 23005C0663F¹ 23005C0664F 23005C0666F 23005C0667F 23005C0668F 23005C0669F 23005C0777F 23005C0781F

23005C0259F 23005C0264F 23005C0266F 23005C0267F 23005C0268F 23005C0269F 23005C0280F 23005C0286F 23005C0287F Gray, Town of 230048 01060001 23005C0288F 23005C0289F 23005C0291F 23005C0292F 23005C0293F 23005C0294F 23005C0481F 23005C0482F 23005C0501F 23005C0502F

1 Panel Not Printed

8 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0503F 23005C0504F Gray, Town of - continued 230048 01060001 23005C0506F 23005C0507F 23005C0508F 23005C0558F 23005C0559F 23005C0564F 23005C0566F 23005C0567F 23005C0568F 23005C0569F 23005C0576F 23005C0577F 23005C0578F 23005C0579F 23005C0581F 23005C0582F 23005C0583F 23005C0584F 23005C0586F Harpswell, Town of 230169 01060001 23005C0587F 23005C0588F 23005C0589F 23005C0591F 23005C0592F 23005C0593F 23005C0594F 23005C0727F 23005C0729F 23005C0731F 23005C0732F 23005C0733F 23005C0734F 23005C0751F 23005C0752F 23005C0753F

9 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0754F 23005C0756F Harpswell, Town of - 230169 01060001 23005C0757F continued 23005C0758F 23005C0759F 23005C0015F¹ 23005C0017F 23005C0018F 23005C0019F 23005C0036F 23005C0038F 23005C0039F 23005C0077F 23005C0079F 23005C0081F 23005C0082F¹ Harrison, Town of 230049 01060001 23005C0083F 23005C0084F 23005C0091F 23005C0092F 23005C0094F 23005C0101F 23005C0102F 23005C0103F 23005C0111F 23005C0112F 23005C0113F

23005C0704F 23005C0706F 23005C0708F 23005C0709F 23005C0712F 23005C0716F Long Island, Town of 231035 01060001 23005C0717F 23005C0718F 23005C0719F 23005C0728F 23005C0736F 23005C0738F

1 Panel Not Printed

10 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0093F 23005C0094F 23005C0111F 23005C0112F 23005C0113F 23005C0114F 23005C0118F 23005C0204F 23005C0206F 23005C0207F 23005C0208F Naples, Town of 230050 01060001 23005C0209F 23005C0216F 23005C0217F 23005C0226F 23005C0227F 23005C0228F 23005C0229F 23005C0231F 23005C0233F 23005C0236F 23005C0237F

23005C0144F¹ 23005C0165F¹ 23005C0170F 23005C0257F 23005C0259F 23005C0280F 23005C0281F 01040002 23005C0282F New Gloucester, Town of 230201 01060001 23005C0283F 23005C0284F 23005C0287F 23005C0291F 23005C0292F 23005C0294F 23005C0305F 23005C0315F

1 Panel Not Printed

11 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0294F 23005C0315F 23005C0506F 23005C0507F 23005C0508F 23005C0509F 23005C0517F North Yarmouth, Town of 230202 01060001 23005C0526F 23005C0527F 23005C0528F 23005C0529F 23005C0531F 23005C0533F 23005C0536F 23005C0537F

23005C0677F 23005C0679F 23005C0681F 23005C0682F 23005C0683F 23005C0684F 23005C0687F 23005C0688F 23005C0689F 23005C0691F 23005C0692F 23005C0693F Portland, City of 230051 01060001 23005C0694F 23005C0703F 23005C0704F 23005C0709F 23005C0711F 23005C0712F 23005C0713F 23005C0714F 23005C0716F 23005C0717F 23005C0718F 23005C0719F

12 Table 1: Listing of NFIP Jurisdictions • continued

If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0728F 23005C0729F 23005C0736F Portland, City of - continued 230051 01060001 23005C0737F 23005C0738F 23005C0827F

23005C0305F 23005C0310F 23005C0315F 23005C0320F Pownal, Town of 230204 01060001 23005C0340F 23005C0527F 23005C0531F 23005C0532F 23005C0533F

23005C0139F 23005C0143F¹ 23005C0242F 23005C0243F 23005C0244F 23005C0251F 23005C0252F 23005C0253F 23005C0254F 23005C0256F 23005C0257F 01040002 Raymond, Town of 230205 23005C0258F 01060001 23005C0259F 23005C0261F 23005C0262F 23005C0263F 23005C0264F 23005C0266F 23005C0267F 23005C0268F 23005C0280F 23005C0456F 23005C0457F

1 Panel Not Printed

13 Table 1: Listing of NFIP Jurisdictions • continued

If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data

23005C0459F Raymond, Town of - 01040002 23005C0476F 230205 continued 01060001 23005C0477F 23005C0478F

23005C0663F¹ 23005C0664F 23005C0668F 23005C0669F 23005C0688F 23005C0689F 23005C0776F 23005C0777F 23005C0779F 23005C0781F 23005C0782F 23005C0783F¹ 23005C0784F 23005C0792F Scarborough, Town of 230052 01060001 23005C0801F 23005C0802F 23005C0803F 23005C0804F 23005C0806F 23005C0807F 23005C0808F 23005C0809F 23005C0811F 23005C0812F 23005C0814F 23005C0816F 23005C0817F 23005C0818F 23005C0836F

23005C0195F 23005C0203F 01060001 23005C0204F Sebago, Town of 230206 01060002 23005C0208F 23005C0211F 23005C0212F

1 Panel Not Printed

14 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0213F 23005C0214F 23005C0216F 23005C0217F 23005C0218F 23005C0219F 23005C0236F 23005C0237F 23005C0238F 01060001 23005C0239F¹ Sebago, Town of 230206 01060002 23005C0243F 23005C0426F 23005C0427F 23005C0431F¹ 23005C0432F 23005C0434F 23005C0451F 23005C0452F¹ 23005C0453F 23005C0456F

23005C0688F 23005C0689F 23005C0693F 23005C0694F 23005C0711F South Portland, City of 230053 01060001 23005C0713F 23005C0714F 23005C0802F 23005C0806F 23005C0807F 23005C0826F

23005C0434F 23005C0441F 23005C0442F 01060001 Standish, Town of 230207 23005C0443F 01060002 23005C0444F 23005C0451F 23005C0452F¹

1 Panel Not Printed

15 Table 1: Listing of NFIP Jurisdictions • continued

If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0453F 23005C0454F 23005C0456F 23005C0457F 23005C0458F 23005C0459F 23005C0461F 23005C0462F 23005C0463F 23005C0464F 23005C0466F 23005C0467F 23005C0468F 23005C0469F 23005C0476F Standish, Town of - 01060001 23005C0477F 230207 continued 01060002 23005C0478F 23005C0479F 23005C0486F 23005C0487F 23005C0488F 23005C0607F 23005C0608F 23005C0609F 23005C0626F 23005C0627F 23005C0628F 23005C0629F 23005C0631F 23005C0632F 23005C0633F 23005C0640F

23005C0513F 23005C0514F 23005C0659F 23005C0667F Westbrook, City of 230054 01060001 23005C0669F 23005C0676F 23005C0677F 23005C0678F

16 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0679F 23005C0681F Westbrook, City of - 23005C0686F 230054 01060001 continued 23005C0687F 23005C0688F 23005C0689F

23005C0264F 23005C0268F 23005C0476F 23005C0477F 23005C0479F 23005C0481F 23005C0482F 23005C0483F 23005C0484F 23005C0487F 23005C0489F 23005C0491F 23005C0492F 23005C0493F Windham, Town of 230189 01060001 23005C0494F 23005C0501F 23005C0503F 23005C0504F 23005C0511F 23005C0512F 23005C0513F 23005C0652F 23005C0656F 23005C0657F 23005C0658F 23005C0659F 23005C0676F 23005C0678F

23005C0528F 23005C0529F Yarmouth, Town of 230055 01060001 23005C0533F 23005C0534F

17 Table 1: Listing of NFIP Jurisdictions • continued If Not Included, HUC-8 Located on Location of Flood Community CID Sub-Basin(s) FIRM Panel(s) Hazard Data 23005C0536F 23005C0537F 23005C0539F 23005C0541F 23005C0542F 23005C0543F Yarmouth, Town of - 230055 01060001 23005C0544F continued 23005C0561F 23005C0562F 23005C0563F 23005C0564F 23005C0706F 23005C0707F 1 Panel Not Printed

1.4 Considerations for using this Flood Insurance Study Report The NFIP encourages State and local governments to implement sound floodplain management programs. To assist in this endeavor, each FIS Report provides floodplain data, which may include a combination of the following: 10-, 4-, 2-, 1-, and 0.2-percent annual chance flood elevations (the 1% annual chance flood elevation is also referred to as the Base Flood Elevation (BFE)); delineations of the 1% annual chance and 0.2% annual chance floodplains; and 1% annual chance floodway. This information is presented on the FIRM and/or in many components of the FIS Report, including Flood Profiles, Floodway Data tables, Summary of Non-Coastal Stillwater Elevations tables, and Coastal Transect Parameters tables (not all components may be provided for a specific FIS).

This section presents important considerations for using the information contained in this FIS Report and the FIRM, including changes in format and content. Figures 1, 2, and 3 present information that applies to using the FIRM with the FIS Report.

• Part or all of this FIS Report may be revised and republished at any time. In addition, part of this FIS Report may be revised by a Letter of Map Revision (LOMR), which does not involve republication or redistribution of the FIS Report. Refer to Section 6.5 of this FIS Report for information about the process to revise the FIS Report and/or FIRM.

It is, therefore, the responsibility of the user to consult with community officials by contacting the community repository to obtain the most current FIS Report components. Communities participating in the NFIP have established repositories of flood hazard data for floodplain management and flood insurance purposes. Community map repository addresses are provided in Table 31, “Map Repositories,” within this FIS Report.

• New FIS Reports are frequently developed for multiple communities, such as entire counties. A countywide FIS Report incorporates previous FIS Reports for individual communities and the unincorporated area of the county (if not jurisdictional) into a single document and supersedes those documents for the purposes of the NFIP.

The initial Countywide FIS Report for Cumberland County became effective on Date [TDB]. Refer to Table 28 for information about subsequent revisions to the FIRMs.

• Selected FIRM panels for the community may contain information (such as floodways and cross sections) that was previously shown separately on the corresponding Flood Boundary and Floodway Map (FBFM) panels. In addition, former flood hazard zone designations have been changed as follows:

Old Zone New Zone A1 through A30 AE V1 through V30 VE B X (shaded) C X (unshaded)

• FEMA does not impose floodplain management requirements or special insurance ratings based on Limit of Moderate Wave Action (LiMWA) delineations at this time. The LiMWA represents the approximate landward limit of the 1.5-foot breaking wave. If the LiMWA is shown on the FIRM, it is being provided by FEMA as information only. For communities that do adopt Zone VE building standards in the area defined by the LiMWA, additional Community Rating System (CRS) credits are available. Refer to Section 2.5.4 for additional information about the LiMWA.

The CRS is a voluntary incentive program that recognizes and encourages community floodplain management activities that exceed the minimum NFIP requirements. Visit the FEMA Web site at www.fema.gov/national-flood-insurance- program-community-rating-system or contact your appropriate FEMA Regional Office for more information about this program.

• FEMA has developed a Guide to Flood Maps (FEMA 258) and online tutorials to assist users in accessing the information contained on the FIRM. These include how to read panels and step-by-step instructions to obtain specific information. To obtain this guide and other assistance in using the FIRM, visit the FEMA Web site at www.fema.gov/online-tutorials .

The FIRM Index in Figure 1 shows the overall FIRM panel layout within Cumberland County, and also displays the panel number and effective date for each FIRM panel in the county. Other information shown on the FIRM Index includes community boundaries, and flooding sources.

19 Figure 1: FIRM Index

OXFORD COUNTY

0015F* 0017F 0036F HUC8 01060001 0018F 0019F 0038F 0039F Presumpscot ¬«117 0055F HUC8 01040002 0056F* 0057F 0076F 0077F 0081F 0082F* 0101F 0102F ¬«37 TOWN OF HARRISON Lower Androscoggin 230049 0058F 0059F 0078F 0079F 0083F 0084F 0103F ¬«93

0065F 0070F 0086F 0087F 0091F 0092F 0111F 0112F 0117F 0136F 0165F* TOWN OF BRIDGTON 0170F ¬«35 230041 ANDROSCOGGIN COUNTY 0090F 0093F 0094F 0113F 0114F 0118F 0119F 0138F 0139F 0143F* 0144F* ¬«122 ¬«117 ¤£302 SAGADAHOC 0185F* COUNTY 0205F 0206F 0207F 0226F 0227F 0231F 0232F 0251F 0252F 0256F 0257F 0280F 0281F 0282F 0305F 0310F 0330F* TOWN OF NAPLES TOWN OF CASCO 0331F TOWN OF NEW GLOUCESTER 230050 230044 230201 0203F 0204F 0208F 0209F 0228F 0229F 0233F 0234F 0253F 0254F 0258F 0259F 0283F ¬«26 0284F 0333F 0334F 0359F TOWN OF RAYMOND 0378F 121 ¬« ¬«85 230205 0195F 0211F 0212F 0216F 0217F 0236F 0237F 0241F 0242F 0262F 0267F 0286F 0287F 0291F 0261F 0266F 0292F 0340F 0346F 0347F ¬«107 0315F 0320F 0361F 0362F 0366F 0367F 0386F ¤£302 ¤£202 ¬«231 TOWN OF POWNAL 295 ¤£1 0213F 0214F 0218F 0219F 0238F 0239F** 0243F ¨¦§ 0244F 0264F 0269F 0289F 125 0263F 0268F 0288F 0293F 0294F 230204 ¬« 0348F 0349F 0363F 0364F 0368F 0369F 0388F TOWN OF SEBAGO TOWN OF GRAY 230206 ¬«11 ¬«136 TOWN OF BRUNSWICK ¤£302 230048 ¬«115 ¬«9 230042 0406F 0407F 0426F 0427F 0431F* 0432F 0451F 0452F** 0456F 0457F 0476F 0477F 0481F 0482F 0501F 0502F 0506F 0507F 0526F 0527F 0531F 0532F 0551F 0552F 0556F 0557F 0576F 0577F 0581F 0582F ¬«5 Sebago ¤£302 TOWN OF Lake NORTH YARMOUTH ¬«115 230202 0408F 0409F 0428F* 0429F* 0433F 0434F 0453F 0454F 0458F 0459F 0478F 0479F 0483F 0484F 0503F 0504F 0508F 0509F TOWN OF 0528F 0529F 0533F 0534F 0553F 0554F 0558F 0559F 0578F 0579F 0583F 0584F TOWN OF BALDWIN FRYE 113 ISLAND TOWN OF FREEPORT ¬« 230200 202 123 231036 ¤£ ¬« 24 0416F 0417F 230046 ¬« 0436F 0437F 0441F 0442F 0461F 0462F 0466F 0467F 0486F 0487F 0491F 0511F 0512F 0516F 0517F 0536F 0492F 0537F 0541F 0542F 0561F 0562F 0566F 0567F 0586F 0587F 0591F 0592F TOWN OF WINDHAM TOWN OF TOWN OF ¬«35 CUMBERLAND TOWN OF HARPSWELL 230189 ¨¦§95 YARMOUTH 230162 230055 230169 0443F 0444F 0463F 0464F 0468F 0469F 0488F 0489F 0493F 0494F 0513F 0514F 0518F 0519F 0538F 0539F TOWN OF STANDISH 0543F 0544F 0563F 0564F 0568F 0569F 0588F 0589F 0593F 0594F ¬«113 ¤£302 HUC8 230207 237 TOWN OF FALMOUTH 114 ¬« 295 ¬« 230045 ¬«9 ¨¦§ 0607F 0626F 0627F 0631F 01060002 0632F 0651F 0652F 0656F 0676F 0681F 0701F 0702F 0657F 0677F 0682F 0706F 0707F 0726F 0727F 0731F 0732F 0751F 0752F 0756F 0757F ¬«26 TOWN OF Saco ¬«25 202 495 ¬«88 ¤£ ¨¦§ CHEBEAGUE ISLAND 231037 0608F 0609F 0628F 0629F 0633F 0634F 0653F 0654F 0658F 0659F 0678F 0679F 0683F 0684F 0703F 0704F 0708F 0709F 0728F 0729F 0733F 0734F 0753F 0754F 0758F 0759F TOWN OF GORHAM CITY OF TOWN OF 230047 WESTBROOK ¤£1 LONG ISLAND 230054 231035 0640F 0642F 0661F 0662F 0666F 0667F 0686F 0687F 0691F 0692F 0711F 0712F 0716F 0717F 0736F 0737F ¬«25 CITY OF PORTLAND CITY OF HUC8 ¬«112 230051 PORTLAND ¤£1A 230051 01060001 0663F* 0664F 0668F 0669F 0688F 0689F 0693F 0694F 0713F 0714F 0718F 0719F 0738F ¬«22 CITY OF SOUTH PORTLAND Casco Presumpscot 114 ¬« 295 230053 Bay 0776F ¨¦§ 0777F 0781F 0782F 0801F 0802F 0806F 0807F 0826F 0827F YORK COUNTY TOWN OF SCARBOROUGH TOWN OF CAPE ELIZABETH Atlantic Ocean 230052 £1 ¤ 230043 0779F 0783F* 0784F 0803F 0804F 0808F 0809F 0828F 0829F §¨¦95 ¬«207 ¬«77 0792F 0811F 0812F 0816F 0817F 0836F 0837F ¬«9

0814F 0818F

ATTENTION: The corporate limits shown on this FIRM Index are based on the best Information available at the time of publication. As such, they may be more current than those shown on FIRM panels issued before TBD

1 inch = 28,000 feet 1:336,000

feet NATIONAL FLOOD INSURANCE PROGRAM 0 7,500 15,000 30,000 45,000 60,000 FLOOD INSURANCE RATE MAP INDEX Map Projection: Universal Transverse Mercator Zone 19 North; CUMBERLAND COUNTY, MAINE (All Jurisdictions) North American Datum 1983 PANELS PRINTED: 0017, 0018, 0019, 0036, 0038, 0039, 0055, 0057, 0058, 0059, 0065, 0070, 0076, 0077, 0078, 0079, 0081, 0083, 0084, 0086, 0087, 0090, 0091, 0092, 0093, 0094, 0101, 0102, 0103, 0111, 0112, 0113, 0114, 0117, 0118, 0119, 0136, 0138, 0139, 0170, 0195, 0203, 0204, 0205, 0206, 0207, 0208, 0209, 0211, 0212, 0213, 0214, 0216, 0217, 0218, 0219, 0226, 0227, 0228, 0229, 0231, 0232, 0233, 0234, 0236, 0237, 0238, 0241, 0242, 0243, 0244, 0251, 0252, 0253, 0254, FEMA THE INFORMATION DEPICTED ON THIS MAP AND SUPPORTING 0256, 0257, 0258, 0259, 0261, 0262, 0263, 0264, 0266, 0267, 0268, 0269, 0280, 0281, 0282, DOCUMENTATION ARE ALSO AVAILABLE IN DIGITAL FORMAT AT 0283, 0284, 0286, 0287, 0288, 0289, 0291, 0292, 0293, 0294, 0305, 0310, 0315, 0320, 0331, REVISED 0333, 0334, 0340, 0346, 0347, 0348, 0349, 0359, 0361, 0362, 0363, 0364, 0366, 0367, 0368, 0369, 0378, 0386, 0388, 0406, 0407, 0408, 0409, 0416, 0417, 0426, 0427, 0432, 0433, 0434, PRELIMINARY HTTP://MSC.FEMA.GOV 0436, 0437, 0441, 0442, 0443, 0444, 0451, 0453, 0454, 0456, 0457, 0458, 0459, 0461, 0462, MAP NUMBER 0463, 0464, 0466, 0467, 0468, 0469, 0476, 0477, 0478, 0479, 0481, 0482, 0483, 0484, 0486, 0487, 0488, 0489, 0491, 0492, 0493, 0494, 0501, 0502, 0503, 0504, 0506, 0507, 0508, 0509, 23005CIND0A 0511, 0512, 0513, 0514, 0516, 0517, 0518, 0519, 0526, 0527, 0528, 0529, 0531, 0532, 0533, 0534, 0536, 0537, 0538, 0539, 0541, 0542, 0543, 0544, 0551, 0552, 0553, 0554, 0556, 0557, 0558, 0559, 0561, 0562, 0563, 0564, 0566, 0567, 0568, 0569, 0576, 0577, 0578, 0579, 0581, 0582, 0583, 0584, 0586, 0587, 0588, 0589, 0591, 0592, 0593, 0594, 0607, 0608, 0609, 0626, SEE FLOOD INSURANCE STUDY FOR ADDITIONAL INFORMATION 0627, 0628, 0629, 0631, 0632, 0633, 0634, 0640, 0642, 0651, 0652, 0653, 0654, 0656, 0657, 0658, 0659, 0661, 0662, 0664, 0666, 0667, 0668, 0669, 0676, 0677, 0678, 0679, 0681, 0682, 0683, 0684, 0686, 0687, 0688, 0689, 0691, 0692, 0693, 0694, 0701, 0702, 0703, 0704, 0706, 0707, 0708, 0709, 0711, 0712, 0713, 0714, 0716, 0717, 0718, 0719, 0726, 0727, 0728, 0729, EFFECTIVE DATE * PANEL NOT PRINTED - NO SPECIAL FLOOD HAZARD AREAS 0731, 0732, 0733, 0734, 0736, 0737, 0738, 0751, 0752, 0753, 0754, 0756, 0757, 0758, 0759, ** PANEL NOT PRINTED - AREA WITHIN ZONE AE (EL 267.1) 0776, 0777, 0779, 0781, 0782, 0784, 0792, 0801, 0802, 0803, 0804, 0806, 0807, 0808, 0809, COUNTY LOCATOR 0811, 0812, 0814, 0816, 0817, 0818, 0826, 0827, 0828, 0829, 0836, 0837

Each FIRM panel may contain specific notes to the user that provide additional information regarding the flood hazard data shown on that map. However, the FIRM panel does not contain enough space to show all the notes that may be relevant in helping to better understand the information on the panel. Figure 2 contains the full list of these notes.

Figure 2: FIRM Notes to Users NOTES TO USERS For information and questions about this map, available products associated with this FIRM including historic versions of this FIRM, how to order products, or the National Flood Insurance Program in general, please call the FEMA Map Information eXchange at 1-877- FEMA-MAP (1-877-336-2627) or visit the FEMA Flood Map Service Center website at msc.fema.gov . Available products may include previously issued Letters of Map Change, a Flood Insurance Study Report, and/or digital versions of this map. Many of these products can be ordered or obtained directly from the website. Users may determine the current map date for each FIRM panel by visiting the FEMA Flood Map Service Center website or by calling the FEMA Map Information eXchange.

Communities annexing land on adjacent FIRM panels must obtain a current copy of the adjacent panel as well as the current FIRM Index. These may be ordered directly from the Flood Map Service Center at the number listed above.

For community and countywide map dates, refer to Table 28 in this FIS Report.

To determine if flood insurance is available in the community, contact your insurance agent or call the National Flood Insurance Program at 1-800-638-6620.

PRELIMINARY FIS REPORT: FEMA maintains information about map features, such as street locations and names, in or near designated flood hazard areas. Requests to revise information in or near designated flood hazard areas may be provided to FEMA during the community review period, at the final Consultation Coordination Officer's meeting, or during the statutory 90-day appeal period. Approved requests for changes will be shown on the final printed FIRM.

The map is for use in administering the NFIP. It may not identify all areas subject to flooding, particularly from local drainage sources of small size. Consult the community map repository to find updated or additional flood hazard information.

BASE FLOOD ELEVATIONS: For more detailed information in areas where Base Flood Elevations (BFEs) and/or floodways have been determined, consult the Flood Profiles and Floodway Data and/or Summary of Non-Coastal Stillwater Elevations tables within this FIS Report. Use the flood elevation data within the FIS Report in conjunction with the FIRM for construction and/or floodplain management.

Coastal Base Flood Elevations shown on the map apply only landward of 0.0' North American Vertical Datum of 1988 (NAVD88). Coastal flood elevations are also provided in the Coastal Transect Parameters table in the FIS Report for this jurisdiction. Elevations shown in the Coastal Transect Parameters table should be used for construction and/or floodplain management purposes when they are higher than the elevations shown on the FIRM.

21 Figure 2. FIRM Notes to Users

FLOODWAY INFORMATION: Boundaries of the floodways were computed at cross sections and interpolated between cross sections. The floodways were based on hydraulic considerations with regard to requirements of the National Flood Insurance Program. Floodway widths and other pertinent floodway data are provided in the FIS Report for this jurisdiction. FLOOD CONTROL STRUCTURE INFORMATION: Certain areas not in Special Flood Hazard Areas may be protected by flood control structures. Refer to Section 4.3 "Non-Levee Flood Protection Measures" of this FIS Report for information on flood control structures for this jurisdiction. PROJECTION INFORMATION: The projection used in the preparation of the map was Universal Transverse Mercator (UTM) Zone 19N. The horizontal datum was the North American Datum of 1983 NAD83, GRS1980 spheroid . Differences in datum, spheroid, projection or State Plane zones used in the production of FIRMs for adjacent jurisdictions may result in slight positional differences in map features across jurisdiction boundaries. These differences do not affect the accuracy of the FIRM. ELEVATION DATUM: Flood elevations on the FIRM are referenced to the North American Vertical Datum of 1988. These flood elevations must be compared to structure and ground elevations referenced to the same vertical datum. For information regarding conversion between the National Geodetic Vertical Datum of 1929 and the North American Vertical Datum of 1988, visit the National Geodetic Survey website at www.ngs.noaa.gov. Local vertical monuments may have been used to create the map. To obtain current monument information, please contact the appropriate local community listed in Table 31 of this FIS Report. BASE MAP INFORMATION: Base map information shown on the FIRM was provided by MeGIS. High resolution orthophoto imagery was produced from 3-inch, 6-inch, and 2-foot pixel cells. Photography was captured during spring 2012 and produced at a scale of 1:600 on August 2012. For information about base maps, refer to Section 6.2 “Base Map” in this FIS Report. The map reflects more detailed and up-to-date stream channel configurations than those shown on the previous FIRM for this jurisdiction. The floodplains and floodways that were transferred from the previous FIRM may have been adjusted to conform to these new stream channel configurations. As a result, the Flood Profiles and Floodway Data tables may reflect stream channel distances that differ from what is shown on the map. Corporate limits shown on the map are based on the best data available at the time of publication. Because changes due to annexations or de-annexations may have occurred after the map was published, map users should contact appropriate community officials to verify current corporate limit locations.

NOTES FOR FIRM INDEX REVISIONS TO INDEX: As new studies are performed and FIRM panels are updated within Cumberland County, Maine, corresponding revisions to the FIRM Index will be incorporated within the FIS Report to reflect the effective dates of those panels. Please refer to Table 28 of this FIS Report to determine the most recent FIRM revision date for each community. The most recent FIRM panel effective date will correspond to the most recent index date.

22 Figure 2. FIRM Notes to Users

SPECIAL NOTES FOR SPECIFIC FIRM PANELS This Notes to Users section was created specifically for Cumberland County, Maine, effective Date [TBD].

COASTAL BARRIER RESOURCES SYSTEM (CBRS): This map includes approximate boundaries of the CBRS for informational purposes only. Flood insurance is not available within CBRS areas for structures that are newly built or substantially improved on or after the date(s) indicated on the map. For more information see www.fws.gov/cbra, the FIS Report, or call the U.S. Fish and Wildlife Service Customer Service Center at 1-800-344-WILD.

LIMIT OF MODERATE WAVE ACTION: Zone AE has been divided by a Limit of Moderate Wave Action (LiMWA). The LiMWA represents the approximate landward limit of the 1.5-foot breaking wave. The effects of wave hazards between Zone VE and the LiMWA (or between the shoreline and the LiMWA for areas where Zone VE is not identified) will be similar to, but less severe than, those in Zone VE.

STATE OF MAINE FLOODWAY NOTE: Under the Maine Revised Statutes Annotated (M.R.S.A) Title 38 § 439-A, 7C where the floodway is not designated on the Flood Insurance Rate Map, the floodway is considered to be the channel of a river or other water course and the adjacent land areas to a distance of one-half the width of the floodplain, as measured from the normal high water mark to the upland limit of the floodplain, unless a technical evaluation certified by a registered professional engineer is provided demonstrating the actual floodway based upon approved FEMA modeling methods.

COASTAL STRUCTURES: Only coastal structures that are certified to provide protection from the 1-percent-annual chance flood are shown on the panels. However, all structures taken into consideration for the purpose of coastal flood hazard analysis and mapping are present in the DFIRM database in S_Gen_Struct.

FLOOD RISK REPORT: A Flood Risk Report (FRR) may be available for many of the flooding sources and communities referenced in this FIS Report. The FRR is provided to increase public awareness of flood risk by helping communities identify the areas within their jurisdictions that have the greatest risks. Although non-regulatory, the information provided within the FRR can assist communities in assessing and evaluating mitigation opportunities to reduce these risks. It can also be used by communities developing or updating flood risk mitigation plans. These plans allow communities to identify and evaluate opportunities to reduce potential loss of life and property. However, the FRR is not intended to be the final authoritative source of all flood risk data for a project area; rather, it should be used with other data sources to paint a comprehensive picture of flood risk.

Each FIRM panel contains an abbreviated legend for the features shown on the maps. However, the FIRM panel does not contain enough space to show the legend for all map features. Figure 3 shows the full legend of all map features. Note that not all of these features may appear on the FIRM panels in Cumberland County.

Figure 3: Map Legend for FIRM

SPECIAL FLOOD HAZARD AREAS: The 1% annual chance flood, also known as the base flood or 100-year flood, has a 1% chance of happening or being exceeded each year. Special Flood Hazard Areas are subject to flooding by the 1% annual chance flood. The Base Flood Elevation is the water surface elevation of the 1% annual chance flood. The floodway is the channel of a stream plus any adjacent floodplain areas that must be kept free of encroachment so that the 1% annual chance flood can be carried without substantial increases in flood heights. See note for specific types. If the floodway is too narrow to be shown, a note is shown. Special Flood Hazard Areas subject to inundation by the 1% annual chance flood (Zones A, AE, AH, AO, AR, A99, V and VE)

Zone A The flood insurance rate zone that corresponds to the 1% annual chance floodplains. No base (1% annual chance) flood elevations (BFEs) or depths are shown within this zone. Zone AE The flood insurance rate zone that corresponds to the 1% annual chance floodplains. Base flood elevations derived from the hydraulic analyses are shown within this zone. Zone AH The flood insurance rate zone that corresponds to the areas of 1% annual chance shallow flooding (usually areas of ponding) where average depths are between 1 and 3 feet. Whole-foot BFEs derived from the hydraulic analyses are shown at selected intervals within this zone. Zone AO The flood insurance rate zone that corresponds to the areas of 1% annual chance shallow flooding (usually sheet flow on sloping terrain) where average depths are between 1 and 3 feet. Average whole-foot depths derived from the hydraulic analyses are shown within this zone. Zone AR The flood insurance rate zone that corresponds to areas that were formerly protected from the 1% annual chance flood by a flood control system that was subsequently decertified. Zone AR indicates that the former flood control system is being restored to provide protection from the 1% annual chance or greater flood. Zone A99 The flood insurance rate zone that corresponds to areas of the 1% annual chance floodplain that will be protected by a Federal flood protection system where construction has reached specified statutory milestones. No base flood elevations or flood depths are shown within this zone. Zone V The flood insurance rate zone that corresponds to the 1% annual chance coastal floodplains that have additional hazards associated with storm waves. Base flood elevations are not shown within this zone. Zone VE Zone VE is the flood insurance rate zone that corresponds to the 1% annual chance coastal floodplains that have additional hazards associated with storm waves. Base flood elevations derived from the coastal analyses are shown within this zone as static whole-foot elevations that apply throughout the zone.

24 Figure 3: Map Legend for FIRM

Regulatory Floodway determined in Zone AE.

Non-encroachment zone (see Section 2.4 of this FIS Report for more information) OTHER AREAS OF FLOOD HAZARD Shaded Zone X: Areas of 0.2% annual chance flood hazards and areas of 1% annual chance flood hazards with average depths of less than 1 foot or with drainage areas less than 1 square mile. Future Conditions 1% Annual Chance Flood Hazard – Zone X: The flood insurance rate zone that corresponds to the 1% annual chance floodplains that are determined based on future-conditions hydrology. No base flood elevations or flood depths are shown within this zone. Area with Reduced Flood Risk due to Levee: Areas where an accredited levee, dike, or other flood control structure has reduced the flood risk from the 1% annual chance flood. Area with Flood Risk due to Levee: Areas where a non-accredited levee, dike, or other flood control structure is shown as providing protection to less than the 1% annual chance flood. OTHER AREAS Zone D (Areas of Undetermined Flood Hazard): The flood insurance rate zone that corresponds to unstudied areas where flood hazards are undetermined, but possible. NO SCREEN Unshaded Zone X: Areas of minimal flood hazard.

FLOOD HAZARD AND OTHER BOUNDARY LINES

Flood Zone Boundary (white line on ortho-photography-based mapping; gray line on vector-based mapping) (ortho) (vector)

Limit of Study

Jurisdiction Boundary

Limit of Moderate Wave Action (LiMWA): Indicates the inland limit of the

area affected by waves greater than 1.5 feet

GENERAL STRUCTURES

Aqueduct Channel Channel, Culvert, Aqueduct, or Storm Sewer Culvert Storm Sewer

25 Figure 3: Map Legend for FIRM

______Dam Jetty Dam, Jetty, Weir Weir

Levee, Dike, or Floodwall

Bridge Bridge

COASTAL BARRIER RESOURCES SYSTEM (CBRS) AND OTHERWISE PROTECTED AREAS (OPA): CBRS areas and OPAs are normally located within or adjacent to Special Flood Hazard Areas.

Coastal Barrier Resources System Area: Labels are shown to clarify where this area shares a boundary with an incorporated area or overlaps with the floodway. CBRS AREA 09/30/2009

Otherwise Protected Area OTHERWISE PROTECTED AREA 09/30/2009

REFERENCE MARKERS

River mile Markers

CROSS SECTION & TRANSECT INFORMATION

Lettered Cross Section with Regulatory Water Surface Elevation (BFE)

Numbered Cross Section with Regulatory Water Surface Elevation (BFE)

Unlettered Cross Section with Regulatory Water Surface Elevation (BFE)

Coastal Transect

Profile Baseline: Indicates the modeled flow path of a stream and is shown on FIRM panels for all valid studies with profiles or otherwise established base flood elevation. Coastal Transect Baseline: Used in the coastal flood hazard model to represent the 0.0-foot elevation contour and the starting point for the transect and the measuring point for the coastal mapping.

Base Flood Elevation Line

26 Figure 3: Map Legend for FIRM

ZONE AE Static Base Flood Elevation value (shown under zone label) (EL 16) ZONE AO (DEPTH 2) Zone designation with Depth ZONE AO (DEPTH 2) Zone designation with Depth and Velocity (VEL 15 FPS) BASE MAP FEATURES Missouri Creek River, Stream or Other Hydrographic Feature

Interstate Highway

U.S. Highway

State Highway

County Highway

MAPLE LANE Street, Road, Avenue Name, or Private Drive if shown on Flood Profile

Railroad RAILROAD

Horizontal Reference Grid Line

Horizontal Reference Grid Ticks

Secondary Grid Crosshairs

Land Grant Name of Land Grant

7 Section Number

R. 43 W. T. 22 N. Range, Township Number

42 76 000m E Horizontal Reference Grid Coordinates (UTM)

365000 FT Horizontal Reference Grid Coordinates (State Plane)

80 °°° 16’ 52.5” Corner Coordinates (Latitude, Longitude)

SECTION 2.0 – FLOODPLAIN MANAGEMENT APPLICATIONS

2.1 Floodplain Boundaries To provide a national standard without regional discrimination, the 1% annual chance (100-year) flood has been adopted by FEMA as the base flood for floodplain management purposes. The 0.2% annual chance (500-year) flood is employed to indicate additional areas of flood hazard in the community.

Each flooding source included in the project scope has been studied and mapped using professional engineering and mapping methodologies that were agreed upon by FEMA and Cumberland County as appropriate to the risk level. Flood risk is evaluated based on factors such as known flood hazards and projected impact on the built environment. Engineering analyses were performed for each studied flooding source to calculate its 1% annual chance flood elevations; elevations corresponding to other floods (e.g. 10-, 4, 2-, 0.2-percent annual chance, etc.) may have also been computed for certain flooding sources. Engineering models and methods are described in detail in Section 5.0 of this FIS Report. The modeled elevations at cross sections were used to delineate the floodplain boundaries on the FIRM; between cross sections, the boundaries were interpolated using elevation data from various sources. More information on specific mapping methods is provided in Section 6.0 of this FIS Report.

Depending on the accuracy of available topographic data (Table 23), study methodologies employed (Section 5.0), and flood risk, certain flooding sources may be mapped to show both the 1% and 0.2% annual chance floodplain boundaries, regulatory water surface elevations (BFEs), and/or a regulatory floodway. Similarly, other flooding sources may be mapped to show only the 1% annual chance floodplain boundary on the FIRM, without published water surface elevations. In cases where the 1% and 0.2% annual chance floodplain boundaries are close together, only the 1% annual chance floodplain boundary is shown on the FIRM. Figure 3, “Map Legend for FIRM”, describes the flood zones that are used on the FIRMs to account for the varying levels of flood risk that exist along flooding sources within the project area. Table 2 and Table 3 indicate the flood zone designations for each flooding source and each community within Cumberland County, respectively.

Table 2, “Flooding Sources Included in this FIS Report,” lists each flooding source, including its study limits, affected communities, mapped zone on the FIRM, and the completion date of its engineering analysis from which the flood elevations on the FIRM and in the FIS Report were derived. Descriptions and dates for the latest hydrologic and hydraulic analyses of the flooding sources are shown in Table 13. Floodplain boundaries for these flooding sources are shown on the FIRM (published separately) using the symbology described in Figure 3. On the map, the 1% annual chance floodplain corresponds to the SFHAs. The 0.2% annual chance floodplain shows areas that, although out of the regulatory floodplain, are still subject to flood hazards.

Small areas within the floodplain boundaries may lie above the flood elevations but cannot be shown due to limitations of the map scale and/or lack of detailed topographic

28 data. The procedures to remove these areas from the SFHA are described in Section 6.5 of this FIS Report.

Table 2: Flooding Sources Included in this FIS Report Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis Cumberland- Approximately 1.38 1980 Androscoggin Brunswick, Town of Sagadahoc county miles upstream of dam 01040002 6.8 Y AE (redelineated River boundary in Town of Brunswick 2013) Cape Elizabeth, VE, AE, Town of; Shoreline at 001 Shoreline at 032 Atlantic Ocean 01060001 110.3 N AO, X 2013 Scarborough, Town (001-032) (001-032) (Shaded) of 1979 Within the Town of Within the Town of Bay of Naples Naples, Town of 01060001 1.2 N AE (redelineated Naples Naples 2013) Douglas Hill Road in 1978 Confluence with Saco Breakneck Brook Baldwin, Town of the Town of West 01060002 3.6 Y AE (redelineated River Baldwin 2013) 1995 Confluence with Fore Warren Avenue in the Capisic Brook Portland, City of 01060001 2.5 Y AE (redelineated River City of Portland 2013) Portland, City of; South Portland, City of; Brunswick, Town of; Cape Elizabeth, Town of; Chebeague Island, Shoreline at 033 Shoreline at 161 Town of; VE, AE, Casco Bay (033-131, 134-149, (033-131, 134-149, 01060001 374.3 N 2013 Cumberland, Town AH, AO 151-152, and 154-161) 151-152, and 154-161) of; Falmouth, Town of; Freeport, Town of; Harpswell, Town of; Long Island, Town of; Yarmouth, Town of

30 Table 2: Flooding Sources Included in this FIS Report • continued Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis Approximately 1.06 miles upstream from its 1978 Confluence with AE, X Clark Brook Westbrook, City of confluence with 01060001 1.3 Y (redelineated Stroudwater River (Shaded) Tributary to Clark 2013) Brook Approximately 1,975 Approximately 3,800 2006 Colley Wright feet upstream of its feet upstream of its Windham, Town of 01060001 0.4 N AE (redelineated Brook confluence with confluence with 2013) Unnamed Tributary Unnamed Tributary Approximately 100 feet 1980 Confluence with upstream of Park AE, X Collyer Brook Gray, Town of 01060001 8.1 Y (redelineated Stevens Brook Street in Town of (Shaded) 2013) Bridgton 1980 Confluence with Park Street in the Town AE, X Corn Shop Brook Bridgton, Town of 01060001 0.2 Y (redelineated Stevens Brook of Bridgton (Shaded) 2013) 1979 Casco, Town of; Within the Town of Within the Town of Crescent Lake 01060001 1.1 N AE (redelineated Raymond, Town of Casco and Raymond Casco and Raymond 2013) Approximately 1.40 1979 Casco, Town of; Confluence with Songo miles upstream of Edes AE, X Crooked River 01060001 6.7 Y (redelineated Naples, Town of River Falls Dam in the Town (Shaded) 2013) of Naples Approximately 1,200 Town of Naples and 1979 Crooked River feet upstream of State AE, X Harrison, Town of Town of Harrison 01060001 1.6 N (redelineated (Town of Harrison) Route 117 in the Town (Shaded) community boundary 2013) of Harrison 1980 Within the Town of Within the Town of Crystal Lake Gray, Town of 01060001 1.0 N AE (redelineated Gray Gray 2013) 1979 Confluence with Long Crystal Lake Dam in Crystal Lake Brook Harrison, Town of 01060001 0.1 Y AE (redelineated Lake the Town of Harrison 2013)

31 Table 2: Flooding Sources Included in this FIS Report • continued

Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis 1980 Mill Pond Dam in the Ditch Brook Windham, Town of Varney’s Mill Dam 01060001 2.4 Y AE, A (redelineated Town of Windham 2013) Approximately 1,350 1978 Confluence with Saco feet upstream from AE, X Dug Hill Brook Baldwin, Town of 01060002 0.7 Y (redelineated River State Route 113 in the (Shaded) 2013) Town of Cornish Approximately 1,560 1995 East Branch Confluence with feet downstream from AE, X Portland, City of 01060001 0.4 N (redelineated Capisic Brook Capisic Brook the confluence of (Shaded) 2013) Capisic Brook 1980 Confluence with Collyer Town of Gloucester Eddy Brook Gray, Town of 01060001 0.3 Y AE (redelineated Brook corporate limits 2013) Confluence with Back Just upstream of Allen AE, X Fall Brook Portland, City of 01060001 2.5 Y 2013 Cove Street (Shaded) Cumberland, Town Within the towns of Within the towns of 2001 Forest Lake of; Gray, Town of; Cumberland, Gray, and Cumberland, Gray, and 01060001 0.3 N AE (redelineated Windham, Town of Windham Windham 2013) Brunswick, Town of; Shoreline at 132 Shoreline at 133 Harpswell Sound 01060001 30.8 N VE, AE 2013 Harpswell, Town of (132, 133) (132, 133) 1980 Within the Town of Within the Town of Highland Lake Bridgton, Town of 01060001 2.1 N AE (redelineated Bridgton Bridgton 2013) Within the Town of Within the Town of 1980 Falmouth, Town of; Highland Lake Falmouth and Falmouth and 01060001 1.0 N AE (redelineated Windham, Town of Windham Windham 2013) 2009 Corporate limits of Hobbs Brook Falmouth, Town of Gray Road 01060001 0.4 N AE (redelineated Falmouth 2013)

32 Table 2: Flooding Sources Included in this FIS Report • continued

Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis Approximately 820 feet 2006 Hobbs Brook Falmouth, Town of Schuster Road upstream of Schuster 01060001 0.1 N AE (redelineated Road 2013) Approximately 3,600 1980 South Portland, City Confluence with Long AE, A, X Jackson Brook feet downstream of the 01060001 2.3 Y (redelineated of Creek (Shaded) Maine Turnpike 2013) 1980 Within the Town of Within the Town of Little Sebago Lake Gray, Town of 01060001 3.1 N AE (redelineated Gray Gray 2013) 1980 South Portland, City Confluence of Fore Confluence with Long Creek 01060001 1.5 Y AE (redelineated of River Jackson Brook 2013) 1979 Within the Town of Within the Town of Long Lake Naples, Town of 01060001 8.3 N AE (redelineated Naples Naples 2013) Approximately 3,450 Approximately 5,525 2006 feet upstream of its feet upstream of its Milliken Brook Windham, Town of 01060001 0.4 N AE (redelineated confluence with confluence with 2013) Inkhorn Brook Inkhorn Brook 1978 Confluence with Austin Street in the AE, A, X Mill Brook Westbrook, City of 01060001 1.6 Y (redelineated Presumpscot River Town of Westbrook (Shaded) 2013) Approximately 1.36 1978 Confluence with miles upstream of AE, A, X Minnow Brook Westbrook, City of 01060001 2.2 Y (redelineated Presumpscot River Brook Road in the (Shaded) 2013) Town of Westbrook Approximately 25 feet 1979 Confluence with upstream of the AE, A, X Nasons Brook Portland, City of 01060001 1.8 Y (redelineated Capisic Brook Portland Railroad (Shaded) 2013) Terminal

33 Table 2: Flooding Sources Included in this FIS Report • continued

Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis Approximately 7,000 2006 North Branch Little feet downstream of its Confluence with Gorham, Town of 01060001 0.2 Y AE (redelineated River confluence with Westcott Brook 2013) Westcott Brook 1979 Within the Town of Within the Town of Panther Pond Raymond, Town of 01060001 2.2 N AE (redelineated Raymond Raymond 2013) Within the Town of Within the Town of Pettingill Pond Windham, Town of 01060001 0.1 N AE 2001 Windham Windham Approximately 50 feet 1978 Confluence with Saco upstream of Chase AE, X Pigeon Brook Baldwin, Town of 01060002 1.9 Y (redelineated River Siding Road in the (Shaded) 2013) Town of West Baldwin Upstream side of 1978 Pigeon Brook Confluence with AE, A, X Baldwin, Town of Chase Siding Road in 01060002 0.9 Y (redelineated Tributary Pigeon Brook (Shaded) the Town of Baldwin 2013) Approximately 1,000 Approximately 3,625 2005 feet upstream of State feet upstream of State Piscataqua River Falmouth, Town of 01060001 0.5 N AE, A (redelineated Route 100 in the Town Route 100 in the Town 2013) of Falmouth of Falmouth Approximately 1,000 1980 Confluence with feet upstream of State AE, A, X Piscataqua River Falmouth, Town of 01060001 2.4 Y (redelineated Presumpscot River Route 100 in the Town (Shaded) 2013) of Falmouth Approximately 1,400 1980 Town of Gray feet upstream of Hunts AE, A, X Pleasant River Gray, Town of 01060001 4.1 Y (redelineated corporate limits Hill Road in the Town (Shaded) 2013) of Gray Portland Harbor Confluence with Fore VE, AE, (Atlantic Ocean Portland, City of Maine State Pier 01060001 110.3 N 2011 River AH and Casco Bay)

34 Table 2: Flooding Sources Included in this FIS Report • continued

Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis 1980 Highway 295 in Town of Falmouth AE, X Presumpscot River Falmouth, Town of 01060001 3.5 Y (redelineated Falmouth corporate limits (Shaded) 2013) 1980 Within the Town of Within the Town of AE, X Presumpscot River Windham, Town of 01060001 6.5 Y (redelineated Windham Windham (Shaded) 2013) 1979 Within the Town of Within the Town of AE, X Presumpscot River Gorham, Town of 01060001 5.2 Y (redelineated Gorham Gorham (Shaded) 2013) Gorham, Standish and 1979 Highway 295 in AE, X Presumpscot River Portland, City of Windham corporate 01060001 3.1 Y (redelineated Falmouth (Shaded) limits 2013) 1978 Within the City of Within the City of AE, X Presumpscot River Westbrook, City of 01060001 3.8 Y (redelineated Westbrook Westbrook (Shaded) 2013) Shoreline at 150 Shoreline at 153 Quahog Bay Harpswell, Town of 01060001 5.9 N AE, VE 2013 (150, 153) (150, 153) Approximately 455 feet 1978 Confluence with Saco upstream of State AE, A, X Quaker Brook Baldwin, Town of 01060002 1.0 Y (redelineated River Route 113 in the Town (Shaded) 2013) of East Baldwin Within the corporate Corporate limits with 1980 South Portland, City limits of South Portland AE, A, X Red Brook the Town of 01060001 1.6 Y (redelineated of from confluence with (Shaded) Scarborough 2013) Jackson Brook Approximately 0.83 1980 Royal River Confluence with Casco miles upstream of AE, A, X Yarmouth, Town of 01060001 2.0 Y (redelineated Downstream Bay North Elm Street (Shaded) 2013) Railroad Town of North Town of New 1980 Royal River AE, A, X Gloucester, Town of Yarmouth corporate Gloucester corporate 01060001 10.6 Y (redelineated Upstream (Shaded) limits limits 2013)

35 Table 2: Flooding Sources Included in this FIS Report • continued Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis 1980 Royal River Within the Town of Within the Town of AE, A, X Gray, Town of 01060001 2.7 Y (redelineated Upstream Gray Gray (Shaded) 2013) Town of North Town of New 1980 Royal River North Yarmouth, AE, A, X Yarmouth corporate Gloucester corporate 01060001 7.9 Y (redelineated Upstream Town of (Shaded) limits limits 2013) 1979 York-Cumberland Town of Baldwin AE, A, X Saco River Standish, Town of 01060002 10.8 Y (redelineated County Boundary corporate limits (Shaded) 2013) 1978 York-Cumberland Cumberland-Oxford AE, A, X Saco River Baldwin, Town of 01060002 12.9 Y (redelineated County Boundary County Boundary lines (Shaded) 2013) Confluence with the 1979 Saco River Left AE, X Standish, Town of Cataract Dam Saco River in the Town 01060001 0.4 Y (redelineated Channel (Shaded) of Standish 2013) Casco, Town of; Frye Island, Town of; Naples, Town of; 1979/1980 Sebago Lake Raymond, Town of; Entire Shoreline Entire Shoreline 01060001 47.7 N AE (redelineated Sebago, Town of; 2013) Standish, Town of; Windham, Town of Confluence with the 1979 Casco, Town of; Confluence with Songo River Bay of Naples in the 01060001 1.6 Y AE (redelineated Naples, Town of Sebago Lake Town of Naples 2013) 1980 Highland Lake Dam in AE, A, X Stevens Brook Bridgton, Town of Kansas Road 01060001 1.6 Y (redelineated the Town of Bridgton (Shaded) 2013) Approximately 75 feet 1979 Confluence with Fore downstream from the Stroudwater River Portland, City of 01060001 1.0 Y AE, A (redelineated River Town of Gorham 2013) corporate limits

36 Table 2: Flooding Sources Included in this FIS Report • continued

Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis Approximately 75 feet 1978 Confluence with Fore downstream from the AE, A, X Stroudwater River Westbrook, City of 01060001 3.8 Y (redelineated River Town of Gorham (Shaded) 2013) corporate limits Approximately 2,000 1980 Confluence with feet upstream of the AE, A, X Thayer Brook Gray, Town of 01060001 2.0 Y (redelineated Pleasant River confluence with (Shaded) 2013) Tributary A Approximately 50 feet 2005 Tributary 1 to upstream of Gorham- Approximately 30 feet Standish, Town of 01060001 0.8 N AE (redelineated Presumpscot River Standish Corporate from Route 35 2013) Limites Confluence with Approximately 1,900 2003 Tributary 2 to Standish, Town of Tributary 1 to feet upstream of 01060001 0.4 N AE (redelineated Presumpscot River Presumpscot River Lucky’s Run 2013) Approximately 250 feet 1980 Confluence with upstream of Farm Tributary A Gray, Town of 01060001 0.3 Y AE (redelineated Thayer Brook Road in the Town of 2013) Gray Approximately 3,500 1978 Tributary to Clark Confluence with Clark feet downstream of the Westbrook, City of 01060001 0.7 Y AE (redelineated Brook Brook confluence with Clark 2013) Brook Approximately 13 feet 1980 South Portland, City Confluence with Fore upstream of Spurwick AE, X Trout Brook 01060001 1.4 Y (redelineated of River Avenue in the Town of (Shaded) 2013) Cape Elizabeth Approximately 2,850 Unnamed Tributary Approximately 520 feet 2006 feet upstream of its to Colley Wright Windham, Town of upstream of private 01060001 0.2 N AE (redelineated confluence with Colley Brook drive 2013) Wright Brook

37 Table 2: Flooding Sources Included in this FIS Report • continued

Length (mi) Area (mi 2) Zone HUC-8 Sub- (streams or (estuaries Floodway shown Date of Flooding Source Community Downstream Limit Upstream Limit Basin(s) coastlines) or ponding) (Y/N) on FIRM Analysis Approximately 700 feet Unnamed Tributary 2005 upstream of its Approximately 510 feet AE, X to Presumpscot Westbrook, City of 01060001 0.4 N (redelineated confluence with upstream of dirt road (Shaded) River 2013) Presumpscot River Approximately 700 feet Approximately 2,000 2006 Unnamed Tributary Standish, Town of downstream of Maine upstream of Maine 01060002 0.6 N AE (redelineated to Rich Mill Brook Central Railroad Central Railroad 2013) Approximately 800 feet Approximately 2,900 2006 Unnamed Tributary Standish, Town of downstream of Maine upstream of Maine 01060002 0.7 N AE (redelineated to Tucker Brook Central Railroad Central Railroad 2013) 1995 West Branch Confluence with Maine Turnpike in the AE, X Portland, City of 01060001 0.5 N (redelineated Capisic Brook Capisic Brook City of Portland (Shaded) 2013) Approximately 150 feet 2006 upstream of its AE, X Westcott Brook Gorham, Town of Plummer Road 01060001 0.3 Y (redelineated confluence with North (Shaded) 2013) Branch of Little River Approximately 1 foot 1980 Confluence with upstream from Willett AE, X Willet Brook Bridgton, Town of 01060001 0.8 Y (redelineated Stevens Brook Road in the Town of (Shaded) 2013) Bridgton Numerous Unnamed 01040002 Tributaries or Refer to FIRM Refer to FIRM Refer to FIRM 01060001 31.5 N A 2012 / 2013 Local Ponding 01060002 Areas

2.2 Floodways Encroachment on floodplains, such as structures and fill, reduces flood-carrying capacity, increases flood heights and velocities, and increases flood hazards in areas beyond the encroachment itself. One aspect of floodplain management involves balancing the economic gain from floodplain development against the resulting increase in flood hazard.

For purposes of the NFIP, a floodway is used as a tool to assist local communities in balancing floodplain development against increasing flood hazard. With this approach, the area of the 1% annual chance floodplain on a river is divided into a floodway and a floodway fringe based on hydraulic modeling. The floodway is the channel of a stream, plus any adjacent floodplain areas, that must be kept free of encroachment in order to carry the 1% annual chance flood. The floodway fringe is the area between the floodway and the 1% annual chance floodplain boundaries where encroachment is permitted. The floodway must be wide enough so that the floodway fringe could be completely obstructed without increasing the water surface elevation of the 1% annual chance flood more than 1 foot at any point. Typical relationships between the floodway and the floodway fringe and their significance to floodplain development are shown in Figure 4.

To participate in the NFIP, Federal regulations require communities to limit increases caused by encroachment to 1.0 foot, provided that hazardous velocities are not produced. The floodways in this project are presented to local agencies as minimum standards that can be adopted directly or that can be used as a basis for additional floodway projects.

Figure 4: Floodway Schematic

Floodway widths presented in this FIS Report and on the FIRM were computed at cross sections. Between cross sections, the floodway boundaries were interpolated. For certain stream segments, floodways were adjusted so that the amount of floodwaters conveyed on each side of the floodplain would be reduced equally. The results of the floodway computations have been tabulated for selected cross sections and are shown in Table 24, “Floodway Data.”

All floodways that were developed for this Flood Risk Project are shown on the FIRM using the symbology described in Figure 3. In cases where the floodway and l% annual chance floodplain boundaries are either close together or collinear, only the floodway boundary has been shown on the FIRM. For information about the delineation of floodways on the FIRM, refer to Section 6.3.

2.3 Base Flood Elevations The hydraulic characteristics of flooding sources were analyzed to provide estimates of the elevations of floods of the selected recurrence intervals. The Base Flood Elevation (BFE) is the elevation of the 1% annual chance flood. These BFEs are most commonly rounded to the whole foot, as shown on the FIRM, but in certain circumstances or locations they may be rounded to 0.1 foot. Cross section lines shown on the FIRM may also be labeled with the BFE rounded to 0.1 foot. Whole-foot BFEs derived from engineering analyses that apply to coastal areas, areas of ponding, or other static areas with little elevation change may also be shown at selected intervals on the FIRM.

Cross sections with BFEs shown on the FIRM correspond to the cross sections shown in the Floodway Data table and Flood Profiles in this FIS Report. BFEs are primarily intended for flood insurance rating purposes. For construction and/or floodplain management purposes, users are cautioned to use the flood elevation data presented in this FIS Report in conjunction with the data shown on the FIRM.

2.4 Non-Encroachment Zones Some States and communities use non-encroachment zones to manage floodplain development. For flooding sources with medium flood risk, field surveys are often not collected and surveyed bridge and culvert geometry is not developed. Standard hydrologic and hydraulic analyses are still performed to determine BFEs in these areas. However, floodways are not typically determined, since specific channel profiles are not developed. To assist communities with managing floodplain development in these areas, a “non-encroachment zone” may be provided. While not a FEMA designated floodway, the non-encroachment zone represents that area around the stream that should be reserved to convey the 1% annual chance flood event. As with a floodway, all surcharges must fall within the acceptable range in the non-encroachment zone.

General setbacks can be used in areas of lower risk (e.g. unnumbered Zone A), but these are not considered sufficient where unnumbered Zone A is replaced by Zone AE. The NFIP requires communities to ensure that any development in a non-encroachment area causes no increase in BFEs. Communities must generally prohibit development within the area defined by the non-encroachment width to meet the NFIP requirement.

2.5 Coastal Flood Hazard Areas For most areas along rivers, streams, and small lakes, BFEs and floodplain boundaries are based on the amount of water expected to enter the area during a 1% annual chance flood and the geometry of the floodplain. Floods in these areas are typically caused by storm events. However, for areas on or near ocean coasts, large rivers, or large bodies of water, BFE and floodplain boundaries may need to be based on additional components, including storm surges and waves. Communities on or near ocean coasts face flood hazards caused by offshore seismic events as well as storm events.

Coastal flooding sources that are included in this Flood Risk Project are shown in Table 2.

2.5.1 Water Elevations and the Effects of Waves Specific terminology is used in coastal analyses to indicate which components have been included in evaluating flood hazards.

The stillwater elevation (SWEL or still water level) is the surface of the water resulting from astronomical tides, storm surge, and freshwater inputs, but excluding wave setup contribution or the effects of waves. • Astronomical tides are periodic rises and falls in large bodies of water caused by the rotation of the earth and by the gravitational forces exerted by the earth, moon and sun. • Storm surge is the additional water depth that occurs during large storm events. These events can bring air pressure changes and strong winds that force water up against the shore. • Freshwater inputs include rainfall that falls directly on the body of water, runoff from surfaces and overland flow, and inputs from rivers.

The 1% annual chance stillwater elevation is the stillwater elevation that has been calculated for a storm surge from a 1% annual chance storm. The 1% annual chance storm surge can be determined from analyses of tidal gage records, statistical study of regional historical storms, or other modeling approaches. Stillwater elevations for storms of other frequencies can be developed using similar approaches.

The total stillwater elevation (also referred to as the mean water level) is the stillwater elevation plus wave setup contribution but excluding the effects of waves. • Wave setup is the increase in stillwater elevation at the shoreline caused by the reduction of waves in shallow water. It occurs as breaking wave momentum is transferred to the water column.

Like the stillwater elevation, the total stillwater elevation is based on a storm of a particular frequency, such as the 1% annual chance storm. Wave setup is typically estimated using standard engineering practices or calculated using models, since tidal gages are often sited in areas sheltered from wave action and do not capture this information.

Coastal analyses may examine the effects of overland waves by analyzing storm- induced erosion, overland wave propagation, wave runup, and/or wave overtopping. • Storm-induced erosion is the modification of existing topography by erosion caused by a specific storm event, as opposed to general erosion that occurs at a more constant rate. • Overland wave propagation describes the combined effects of variation in ground elevation, vegetation, and physical features on wave characteristics as waves move onshore. • Wave runup is the uprush of water from wave action on a shore barrier. It is a function of the roughness and geometry of the shoreline at the point where the stillwater elevation intersects the land. • Wave overtopping refers to wave runup that occurs when waves pass over the crest of a barrier.

Figure 5: Wave Runup Transect Schematic

2.5.2 Floodplain Boundaries and BFEs for Coastal Areas For coastal communities along the Atlantic and Pacific Oceans, the Gulf of Mexico, the Great Lakes, and the Caribbean Sea, flood hazards must take into account how storm surges, waves, and extreme tides interact with factors such as topography and vegetation. Storm surge and waves must also be considered in assessing flood risk for certain communities on rivers or large inland bodies of water.

Beyond areas that are affected by waves and tides, coastal communities can also have riverine floodplains with designated floodways, as described in previous sections.

Floodplain Boundaries In many coastal areas, storm surge is the principle component of flooding. The extent of the 1% annual chance floodplain in these areas is derived from the total stillwater elevation (stillwater elevation including storm surge plus wave setup) for the 1% annual chance storm. The methods that were used for calculation of total stillwater elevations for coastal areas are described in Section 5.3 of this FIS Report. Location of total

stillwater elevations for coastal areas are shown in Figure 8, “1% Annual Chance Total Stillwater Levels for Coastal Areas.”

In some areas, the 1% annual chance floodplain is determined based on the limit of wave runup or wave overtopping for the 1% annual chance storm surge. The methods that were used for calculation of wave hazards are described in Section 5.3 of this FIS Report.

Table 26 presents the types of coastal analyses that were used in mapping the 1% annual chance floodplain in coastal areas.

Coastal BFEs Coastal BFEs are calculated as the total stillwater elevation (stillwater elevation including storm surge plus wave setup) for the 1% annual chance storm plus the additional flood hazard from overland wave effects (storm-induced erosion, overland wave propagation, wave runup and wave overtopping).

Where they apply, coastal BFEs are calculated along transects extending from offshore to the limit of coastal flooding onshore. Results of these analyses are accurate until local topography, vegetation, or development type and density within the community undergoes major changes.

Parameters that were included in calculating coastal BFEs for each transect included in this FIS Report are presented in Table 17, “Coastal Transect Parameters.” The locations of transects are shown in Figure 9, “Transect Location Map.” More detailed information about the methods used in coastal analyses and the results of intermediate steps in the coastal analyses are presented in Section 5.3 of this FIS Report. Additional information on specific mapping methods is provided in Section 6.4 of this FIS Report.

2.5.3 Coastal High Hazard Areas Certain areas along the open coast and other areas may have higher risk of experiencing structural damage caused by wave action and/or high-velocity water during the 1% annual chance flood. These areas will be identified on the FIRM as Coastal High Hazard Areas.

• Coastal High Hazard Area (CHHA) is a SFHA extending from offshore to the inland limit of the primary frontal dune (PFD) or any other area subject to damages caused by wave action and/or high-velocity water during the 1% annual chance flood. • Primary Frontal Dune (PFD) is a continuous or nearly continuous mound or ridge of sand with relatively steep slopes immediately landward and adjacent to the beach. The PFD is subject to erosion and overtopping from high tides and waves during major coastal storms.

CHHAs are designated as “V” zones (for “velocity wave zones”) and are subject to more stringent regulatory requirements and a different flood insurance rate structure. The areas of greatest risk are shown as VE on the FIRM. Zone VE is further subdivided into elevation zones and shown with BFEs on the FIRM.

The landward limit of the PFD occurs at a point where there is a distinct change from a relatively steep slope to a relatively mild slope; this point represents the landward extension of Zone VE. Areas of lower risk in the CHHA are designated with Zone V on the FIRM. More detailed information about the identification and designation of Zone VE is presented in Section 6.4 of this FIS Report.

Areas that are not within the CHHA but are SFHAs may still be impacted by coastal flooding and damaging waves; these areas are shown as “A” zones on the FIRM.

Figure 6, “Coastal Transect Schematic,” illustrates the relationship between the base flood elevation, the 1% annual chance stillwater elevation, and the ground profile as well as the location of the Zone VE and Zone AE areas in an area without a PFD subject to overland wave propagation. This figure also illustrates energy dissipation and regeneration of a wave as it moves inland.

Figure 6: Coastal Transect Schematic

Methods used in coastal analyses in this Flood Risk Project are presented in Section 5.3 and mapping methods are provided in Section 6.4 of this FIS Report.

Coastal floodplains are shown on the FIRM using the symbology described in Figure 3, “Map Legend for FIRM.” In many cases, the BFE on the FIRM is higher than the stillwater elevations shown in Table 17 due to the presence of wave effects. The higher elevation should be used for construction and/or floodplain management purposes.

2.5.4 Limit of Moderate Wave Action Laboratory tests and field investigations have shown that wave heights as little as 1.5 feet can cause damage to and failure of typical Zone AE building construction. Wood- frame, light gage steel, or masonry walls on shallow footings or slabs are subject to damage when exposed to waves less than 3 feet in height. Other flood hazards associated with coastal waves (floating debris, high velocity flow, erosion, and scour) can also damage Zone AE construction.

Therefore, a LiMWA boundary may be shown on the FIRM as an informational layer to assist coastal communities in safe rebuilding practices. The LiMWA represents the approximate landward limit of the 1.5-foot breaking wave. The location of the LiMWA relative to Zone VE and Zone AE is shown in Figure 6.

The effects of wave hazards in Zone AE between Zone VE (or the shoreline where Zone VE is not identified) and the limit of the LiMWA boundary are similar to, but less severe than, those in Zone VE where 3-foot or greater breaking waves are projected to occur during the 1% annual chance flooding event. Communities are therefore encouraged to adopt and enforce more stringent floodplain management requirements than the minimum NFIP requirements in the LiMWA. The NFIP Community Rating System provides credits for these actions.

Where wave runup elevations dominate over wave heights, there is no evidence to date of significant damage to residential structures by runup depths less than 3 feet. Examples of these areas include areas with steeply sloped beaches, bluffs, or flood protection structures that lie parallel to the shore. In these areas, the FIRM shows the LiMWA immediately landward of the VE/AE boundary. Similarly, in areas where the zone VE designation is based on the presence of a primary frontal dune or wave overtopping, the LiMWA is delineated immediately landward of the Zone VE/AE boundary.

SECTION 3.0 – INSURANCE APPLICATIONS

3.1 National Flood Insurance Program Insurance Zones For flood insurance applications, the FIRM designates flood insurance rate zones as described in Figure 3, “Map Legend for FIRM.” Flood insurance zone designations are assigned to flooding sources based on the results of the hydraulic or coastal analyses. Insurance agents use the zones shown on the FIRM and depths and base flood elevations in this FIS Report in conjunction with information on structures and their contents to assign premium rates for flood insurance policies.

The 1% annual chance floodplain boundary corresponds to the boundary of the areas of special flood hazards (e.g. Zones A, AE, V, VE, etc.), and the 0.2% annual chance floodplain boundary corresponds to the boundary of areas of additional flood hazards.

Table 3 lists the flood insurance zones in Cumberland County.

Table 3: Flood Zone Designations by Community

Community Flood Zone(s) Baldwin, Town of A, AE, X Bridgton, Town of A, AE, X Brunswick, Town of A, AE, VE, X Cape Elizabeth, Town of A, AE, AO, VE, X Casco, Town of A, AE, X Chebeague Island, Town of AE, VE, X Cumberland, Town of A, AE, VE, X Falmouth, Town of A, AE, VE, X Freeport, Town of A, AE, VE, X Frye Island, Town of AE, X Gorham, Town of A, AE, X Gray, Town of A, AE, X Harpswell, Town of AE, VE, X Harrison, Town of A, AE, X Long Island, Town of AE, VE, X Naples, Town of A, AE, X New Gloucester, Town of A, AE, X North Yarmouth, Town of A, AE, X Portland, City of A, AE, AH, AO, VE, X Pownal, Town of A, X Raymond, Town of A, AE, X Scarborough, Town of A, AE, VE, X Sebago, Town of A, AE, X South Portland, City of A, AE, VE, X Standish, Town of A, AE, X Westbrook, City of A, AE, X Windham, Town of A, AE, X Yarmouth, Town of A, AE, VE, X

3.2 Coastal Barrier Resources System The Coastal Barrier Resources Act (CBRA) of 1982 was established by Congress to create areas along the Atlantic and Gulf coasts and the Great Lakes, where restrictions for Federal financial assistance including flood insurance are prohibited. In 1990,

Congress passed the Coastal Barrier Improvement Act (CBIA), which increased the extent of areas established by the CBRA and added “Otherwise Protected Areas” (OPA) to the system. These areas are collectively referred to as the John. H Chafee Coastal Barrier Resources System (CBRS). The CBRS boundaries that have been identified in the project area are in Table 4, “Coastal Barrier Resource System Information.”

Table 4: Coastal Barrier Resources System Information

Date CBRS Area FIRM Panel Primary Flooding Source CBRS/OPA Type Established Number(s)

23005C0812F 23005C0816F Atlantic Ocean CBRS 10/1/1983 23005C0817F 23005C0836F

23005C0828F Atlantic Ocean CBRS 11/16/1990 23005C0836F 23005C0828F 23005C0829F Atlantic Ocean OPA 11/16/1991 23005C0836F 23005C0837F 23005C0726F Casco Bay CBRS 10/1/1983 23005C0728F

23005C0707F CBRS 11/16/1990 23005C0709F Casco Bay 23005C0728F 23005C0729F

23005C0569F Harpswell Sound CBRS 2/24/1997 23005C0588F

23005C0569F Harpswell Sound CBRS 11/16/1990 23005C0588F

SECTION 4.0 – AREA STUDIED

4.1 Basin Description Table 5 contains a description of the characteristics of the HUC-8 sub-basins within which each community falls. The table includes the main flooding sources within each basin, a brief description of the basin, and its drainage area.

Table 5: Basin Characteristics

Drainage HUC-8 Primary Area HUC-8 Sub- Sub-Basin Flooding (square Basin Name Number Source Description of Affected Area miles) This watershed intersects some of the towns on the southwest boundary of Cumberland county. Saco 01060002 Saco River 1,701 It accounts for the Saco River and it's tributaries in Baldwin and Standish. This watershed intersects some of the towns on the northeast Lower Lower boundary of Cumberland county. 01040002 Androscoggin 2,157 Androscoggin The Androscoggin River in River Brunswick is coverd by this subbasin. Largest watershed within Presumpscot Cumberland County, fully Presumpscot 01060001 1,424 River encompassing 19 out of 28 towns in the county.

4.2 Principal Flood Problems Table 6 contains a description of the principal flood problems that have been noted for Cumberland County by flooding source.

Table 6: Principal Flood Problems

Flooding Source Description of Flood Problems Androscoggin Combination of heavy spring rains and melting snow River A major flood on Breakneck Brook occurred in 1939 as a result of a localized Breakneck storm centered over the drainage basin. A total of $105,000 in damages to Brook bridges, roads, and private property occurred during this flood. USGS stream gage no. 01059800 is located on Collyer Brook in Gray and has records dating from September 1964. The highest recorded discharge at this gage was 1,220 cfs on December 27, 1969. Due to its short period of record, Collyer Brook an adequate frequency analysis could not be made for this gage; however, based on the TR-20 watershed model, the December 27, 1969 discharge had a recurrence interval of approximately 30 years. Flooding on Highland and Long Lakes in Bridgton damaged residences, Corn Shop seasonal homes, businesses, property, and roads. On Corn Shop Brook, Brook flooding resulted in damage to numerous businesses, several residences, public buildings, roads, and bridges.

Table 6: Principal Flood Problems • continued Flooding Source Description of Flood Problems A substantial number of seasonal homes have been constructed within the floodplains of the Crooked and Songo Rivers. Many of these properties sustain Crooked River damage from relatively frequent floods. Major floods have occurred in 1896, 1936, 1942, and 1953. Because of the small drainage area and short reaches between dams, the Presumpscot Presumpscot River can rise from normal to flood flow in a short period of time. River Once flood discharges are attained, high flows can persist for several days while the many ponds behind dams in the basin are drained to normal levels. The flood of record occurred on March 13, 1977, and had a peak discharge of Royal River 11,500 cfs and an estimated recurrence interval in excess of 1-percent-annual- Downstream chance. The major flood related damage along the Royal River (upstream) in North Royal River Yarmouth and Gray has been to a brickyard, several homes, farmland, roads, Upstream and bridges. In Standish, major floods on the Saco River have occurred in the spring, usually the result of heavy rainfall combined with snowmelt. Although flooding has occurred during other months, 10 of the 14 highest floods on record occurred during March, April, or May. Heavy rainfall associated with hurricanes Saco River moving up the coast of Maine has caused flooding in the fall. The most severe flooding occurs in the early spring as a result of snowmelt and heavy rain in conjunction with ice jams. Additional floods, generally less severe, also occur in late summer as a result of hurricanes and tropical storms. Major floods occurred on Stevens Brook in 1896, 1936, and 1953. The most destructive flood is that of March 1953. Under present conditions, the 1953 Stevens Brook flood was estimated to have a recurrence interval of approximately 1-percent- annual-chance. Major floods occurred on Willett Brook in 1896, 1936, and 1953. The most destructive flood is that of March 1953. Under present conditions, the 1953 Willet Brook flood was estimated to have a recurrence interval of approximately 1-percent- annual-chance.

Table 7 contains information about historic flood elevations in the communities within Cumberland County.

Table 7: Historic Flooding Elevations [Not Applicable to this Flood Risk Project]

4.3 Non-Levee Flood Protection Measures Table 8 contains information about non-levee flood protection measures within Cumberland County such as dams, jetties, and or dikes. Levees are addressed in Section 4.4 of this FIS Report.

Table 8: Non-Levee Flood Protection Measures

Flooding Type of Description Source Structure Name Measure Location of Measure Central Maine Androscoggin Power Company Dam Brunswick N/A River Dam Along the shore of the Androscoggin Dam Androscoggin River in N/A River Harpswell Atlantic Jetty Various Locations N/A Ocean Atlantic Revetment Various Locations N/A Ocean Atlantic Seawall Various Locations N/A Ocean At the coast of Broad Sound in Broad Sound Revetment N/A Harpswell Broad Sound Seawall Various Locations N/A Buttermilk Revetment Various Locations N/A Cove Buttermilk At the coast of Broad Sound in Seawall N/A Cove Harpswell Capisic Dam Various Locations N/A Brook Casco Bay Jetty Various Locations N/A Casco Bay Revetment Various Locations N/A Casco Bay Seawall Various Locations N/A Collyer Brook Old Mill Dam Dam Gray N/A Collyer Brook Pineland Dam Dam Gray N/A Crooked Edes Falls Dam Dam Naples N/A River Crooked Scribner'S Mill Dam Harrison N/A River Dam Collins Pond Ditch Brook Dam Windham N/A Dam Ditch Brook Mill Pond Dam Dam Windham N/A Varney'S Mill Ditch Brook Dam Windham N/A Dam Doughty Revetment Various Locations N/A Cove Fore River Revetment Various Locations N/A

Table 8: Non•Levee Flood Protection Measures • continued Flooding Type of Description Source Structure Name Measure Location of Measure At the coast of Broad Sound in Fore River Seawall N/A Harpswell Gun Point Revetment Various Locations N/A Cove Harpswell Revetment Various Locations N/A Sound Harpswell Seawall Various Locations N/A Sound Harraseeket At the shoreline of Harraseeket Revetment N/A River River in Yarmouth Jackson Clark Pond Dam Dam South Portland N/A Brook Little Sebago Little Sebago Dam Windham N/A Lake Lake Dam Little Sebago Sebago Lake Dam Standish N/A Lake Dam Mackeral Revetment Various Locations N/A Cove Mackeral Seawall Various Locations N/A Cove Maquoit Bay Revetment Various Locations N/A At the shoreline of Harraseeket Maquoit Bay Seawall N/A River in Yarmouth Merepoint Revetment Various Locations N/A Bay Merepoint At the shoreline of Harraseeket Seawall N/A Bay River in Yarmouth Middle Bay Revetment Various Locations N/A Middle Bay Seawall Various Locations N/A New Meadow At the shoreline of New Meadow Revetment N/A River River in Harpswell New Meadows Revetment Various Locations N/A River New Meadows Seawall Various Locations N/A River Presumpscot Abandoned Dam Falmouth N/A River Dam

Table 8: Non•Levee Flood Protection Measures • continued Flooding Type of Description Source Structure Name Measure Location of Measure Presumpscot Dundee Dam Dam Gorham N/A River Presumpscot Little Falls Dam Dam Gorham, Windham N/A River Presumpscot Newhall Dam Dam Gorham, Windham N/A River Presumpscot North Gorham Dam Gorham, Windham N/A River Dam Presumpscot Power Station Dam Windham N/A River Dam Presumpscot South Windham Dam Gorham, Windham N/A River Dam Presumpscot Revetment Various Locations N/A River

Royal River Dam Various Locations N/A

Bonnie Eagle Saco River Dam Standish N/A Dam Bonny Eagle Saco River Hydro Station Dam Standish N/A Dam

Saco River Hiram Falls Dam Dam Baldwin N/A

At the shoreline of the Scarborough Revetment Scarborough River in Cape N/A River Elizabeth At the shoreline of the Scarborough Seawall Scarborough River in Cape N/A River Elizabeth Songo Lock Songo River Dam Naples N/A Dam Stevens Bisbee Mill Dam Dam Bridgton N/A Brook Stevens Highland Lake Dam Bridgton N/A Brook Dam Stevens Tannery Dam Dam Bridgton N/A Brook Stevens Downstream of Highland Lake Dam N/A Brook Dam Stroudwater Just before Fore River in Dam N/A River Scarborough

4.4 Levees This section is not applicable to this Flood Risk Project.

Table 9: Levees [Not Applicable to this Flood Risk Project]

SECTION 5.0 – ENGINEERING METHODS

For the flooding sources in the community, standard hydrologic and hydraulic study methods were used to determine the flood hazard data required for this study. Flood events of a magnitude that are expected to be equaled or exceeded at least once on the average during any 10-, 25-, 50-, 100-, or 500-year period (recurrence interval) have been selected as having special significance for floodplain management and for flood insurance rates. These events, commonly termed the 10-, 25-, 50-, 100-, and 500-year floods, have a 10-, 4-, 2-, 1-, and 0.2% annual chance, respectively, of being equaled or exceeded during any year.

Although the recurrence interval represents the long-term, average period between floods of a specific magnitude, rare floods could occur at short intervals or even within the same year. The risk of experiencing a rare flood increases when periods greater than 1 year are considered. For example, the risk of having a flood that equals or exceeds the 100-year flood (1-percent chance of annual exceedance) during the term of a 30-year mortgage is approximately 26 percent (about 3 in 10); for any 90-year period, the risk increases to approximately 60 percent (6 in 10). The analyses reported herein reflect flooding potentials based on conditions existing in the community at the time of completion of this study. Maps and flood elevations will be amended periodically to reflect future changes.

The engineering analyses described here incorporate the results of previously issued Letters of Map Change (LOMCs) listed in Table 27, “Incorporated Letters of Map Change”, which include Letters of Map Revision (LOMRs). For more information about LOMRs, refer to Section 6.5, “FIRM Revisions.”

5.1 Hydrologic Analyses Hydrologic analyses were carried out to establish the peak elevation-frequency relationships for floods of the selected recurrence intervals for each flooding source studied. Hydrologic analyses are typically performed at the watershed level. Depending on factors such as watershed size and shape, land use and urbanization, and natural or man-made storage, various models or methodologies may be applied. A summary of the hydrologic methods applied to develop the discharges used in the hydraulic analyses for each stream is provided in Table 13. Greater detail (including assumptions, analysis, and results) is available in the archived project documentation.

Pre-countywide Analyses

Flood discharge estimates for Stevens, Willett, and Corn Shop Brooks in Bridgton (FEMA 1981a), Songo River and Crooked River in Casco and Naples (FEMA 1980b and FEMA 1981c), Pleasant River, Collyer Brook, Thayer Brook, Little Sebago Lake, Tributary A and Eddy Brook in Gray (FEMA 1981g), Crooked River (Town of Harrison) and Crystal Lake Brook in Harrison (FEMA 1981b), Royal River (upstream) in New Gloucester, North Yarmouth and Gray (FEMA 1981d, FEMA 1981e, and FEMA 1981g), Capisic Brook, East Branch Capisic Brook and West Branch Capisic Brook in the City of Portland (FEMA 1988) were generated from the U.S. Department of Agriculture, Natural Resources Conservation Service (USDA NRCS) TR-20 hydrologic evaluation model (USDA NRCS 1991). This model utilizes such variables as rainfall-frequency data, soil type, antecedent moisture condition, land use, time of concentration, and drainage area.

Those for the Royal River (downstream) were correlated with statistical analyses of USGS stream gage no. 0106000 at Yarmouth, Maine (FEMA 1984e). The discharges used for the Pleasant River basin and Little Sebago Lake were checked against the USGS regression equation for Maine (USGS 1975).

The attenuation of peak discharges on the Crooked River (Town of Harrison) is caused primarily by an increased storage in the overbank and channel areas.

For the Stroudwater River, discharges were obtained from the USDA NRCS flood hazard analyses for the river (FEMA 1988). The 10-, 1-, and 0.2-percent-annual-chance discharges were given, and the 2-percent-annual-chance discharge was interpolated.

Discharges for several flooding sources within Cumberland were determined using a regional equation developed by USGS. Peak discharges developed for the 10-, 2-, 1-, and 0.2-percent-annual-chance floods at the USGS gaging stations by a log-Pearson Type III analysis were transposed to other stations by the following formula:

0.8 Q/Q g = (A/A g)

where Q and Q g are the discharges at the station and the gage, respectively, and A and Ag are the drainage areas at these locations (WRC 1976).

Below is a compilation of the flooding sources that used the log-Pearson Type III analysis and formula described above:

Discharges for Capisic Brook, from its confluence with the Fore River to Warren Avenue and Nasons Brook were determined using the regional equation developed by USGS (FEMA 1988). The 10-, 2-, and 1-percent-annual-chance discharges at several stations on the streams were calculated. The 0.2-percent-annual-chance discharge at each station was extrapolated from a log-normal plot of the three calculated flow values.

In Baldwin, a USGS gage (no. 01066000) located at Cornish, Maine, on the Saco River, was used to establish the peak discharge-frequency relationships. These discharges are based on statistical analysis of discharge records covering a 60-year record (USGS 1960 and USGS 1976a). Values of the 10-, 2-, 1-, and 0.2-percent-annual-chance peak discharges were obtained from a log-Pearson Type III distribution of annual peak flow

data in accordance with the U.S. Water Resources Council Bulletin No. 17 (WRC 1976). Flood discharges for the remaining streams in Baldwin were based on the USGS Open- File Report 75-292, “A Technique for Estimating the Magnitude and Frequency of floods in Maine,” which is a regional method based on regression analysis (USGS 1975).

In Yarmouth, for the riverine portion of the Royal River (downstream), peak discharges were developed from a weighted combination of the Maine Regional Equation prepared by USGS and flows obtained from the gaging station (no. 010600000, 30 years of record) (USGS 1975). The 10-, 2-, and 1-percent-annual-chance peak flows at several stations on the river were calculated. The 0.2-percent-annual-chance discharge at each station was extrapolated from a log-normal plot of the three calculated flow values. A log-Pearson Type III distribution of annual peak flow data was used to obtain 10-, 2-, 1-, and 0.2-percent-annual-chance peak discharges from the gage (WRC 1976). The flows from the gage were transposed to points along the Royal River (downstream).

Values of the 10-, 2-, 1-, and 0.2-percent-annual-chance peak discharges at the outlet of Sebago Lake in Windham were obtained from a log-Pearson Type III distribution of annual peak flow data according to the Water Resources Council Bulletin 17A (FEMA 1981h and WRC 1977). Using the methods outlined in USGS Open-File Report 75-292, the Presumpscot River flows were adjusted for a drainage area increase below the confluence with the Pleasant River and below the confluence of the Little River (USGS 1975). The values of the peak flows at the 10-, 2-, 1-, and 0.2-percent-annual-chance recurrence intervals at each point of interest were obtained using equations outlined in Open-File Report 75-292 (USGS 1975).

In Brunswick, the stream gaging station on the Androscoggin River at Auburn (no. 01059000, with 49 years of record) was used to aid in defining frequency-discharge relationships for the river (FEMA 1986).

Peak discharges for Trout Brook, Long Creek, Jackson Brook, Red Brook and Piscataqua River were developed using the regional equation prepared by USGS as well (FEMA 1984d and USGS 1975). The 10-, 2-, and 1-percent-annual-chance peak flows at several locations on Trout Brook and Piscataqua River were calculated. The 0.2- percent-annual-chance discharge was extrapolated from a log-normal plot of the three calculated flow values.

Discharges for the Presumpscot River in Falmouth and Portland were taken from the FIS for the City of Westbrook and transposed by the drainage area discharge ratio (FEMA 1980f).

Peak discharges for the 10-, 2-, 1-, and 0.2-percent-annual-chance floods at the spillway of Highland Lake (Town of Falmouth) were determined by hydrologic routing methods (FEMA 1984a). In the routing, it was assumed that the lake was full to the top of the spillway before the storm runoff began entering the lake. This assumption was made because the lake is not regulated to control floods, and it was desired to start with the worst possible conditions. Calculations were made to determine a lake storage curve, a rating curve for the spillway, and an inflow hydrograph. From these working curves, discharges for the 10-, 2-, 1-, and 0.2-percent-annual-chance floods were developed.

In Gorham, the principal source of data for the Presumpscot River is streamflow records published by USGS (station no. 01064000, January 1887 to 1977). In addition, USGS has operated a gage at West Falmouth since October 1975 (station no. 01064140). This station was operating in March 1977 when other USGS gaging stations in the area recorded peak flows with a 0.2-percent-annual-chance recurrence interval.

In Raymond, Sebago, and Windham, the principal source of data for Sebago Lake was the record of lake elevations maintained by S.D. Warren Company for 106 years (1872 to 1977).

Values of the 10-, 2-, l-, and 0.2-percent-annual-chance peak stages for Sebago Lake were obtained by graphical methods. These values of peak stages were plotted using the Weibull formula:

PLOTTING POSITION (exceedence probability) = M/(N+l), where M is the rank of the event and N is the number of events. The values were plotted against the annual maximum lake elevations and a curve was fitted to the data. The peak stage values at the needed recurrence intervals were selected from this curve. .

The source of data for Panther Pond was also records of lake elevations for 38 years (1920 to 1958). The dam at the outlet of Panther Pond also controls the water-surface elevation of Crescent Lake. Values of peak flows at the outlet of Panther Pond and Crescent Lake were determined by using equations developed by R.A. Morrill (FEMA 1980c). These equations relate flood flows to drainage area, main channel slope, and storage area. This method was also adopted for calculating flow for the 0.2-percent- annual-chance recurrence interval.

The estimated flood flows were then used to compute the head on the Panther Pond outlet dam. The geometric features of the dam were surveyed, and all data needed to compute heads were obtained in the field. The formula for computing flow over a broad- crested weir: Q = CLH 3/2 was assumed to be valid for computing flow over the spillway. For flow through the deep control gate, fully opened, the equation used was: Q = CA * 2 gH. In the first formula, Q is discharge in cubic feet per second, C is the coefficient of discharge, L is the length of weir in feet, and H is the head on the dam, in feet (FEMA 1980c). In the second formula, A is the area of the gate-opening, in square feet; g = acceleration of gravity, in feet per second squared; H is the head of water on the gate, in feet; and C is the coefficient of discharge (H.W. King 1954). The peak stage values at the needed recurrence intervals were then computed. The values determined were checked against values determined by formulas given in Bulletin 17A of the Water Resources Council (WRC 1977). It should be noted that the values used in this check were taken from data on maximum month-end lake elevations.

In Westbrook, discharges from Sebago Lake to the Presumpscot River have been recorded continuously since 1887 by the S.D. Warren Company and published by USGS. In 1975, USGS installed a stream gage on the Presumpscot River in Falmouth at the Maine Turnpike bridge crossing, just downstream of the study area. The only other flow data available for the lower Presumpscot River are miscellaneous peak discharges computed at the Cumberland Mills Dam in Westbrook. Extensive regulation of Sebago Lake has greatly attenuated peak flows from the upper 436 square miles of the

Presumpscot River watershed. Runoff from the lower 154-square mile drainage area is the primary contributor to flood flows in Westbrook. The Royal River (downstream) at Yarmouth, Maine, located adjacent to the Presumpscot River basin, has a drainage area of 141 square miles and is considered somewhat indicative of the runoff characteristics of the lower Presumpscot River. Analysis of 28 years of USGS flow data for this stream was therefore used as a basis for estimating discharge frequencies for the lower Presumpscot River. A frequency curve was developed for the Royal River (downstream) using a standard log-Pearson Type III statistical distribution (WRC 1976). Discharge frequencies for the Presumpscot River watershed, between Sebago Lake and Cumberland Mills Dam, were developed by multiplying the Royal River (downstream) curve by the ratio of peak flows experienced at Cumberland Mills Dam and the Royal River (downstream) during the floods of March 1936, September 1954, and March 1977.

An assumed coincident baseflow contribution of 600 cfs from Sebago Lake was then added to the Presumpscot River discharges, reflecting the desynchronization accomplished through regulation at the Eel Weir Canal by the S.D. Warren Company. Frequency data for the Presumpscot River were then transferred downstream to the Falmouth town line by ratio of net drainage areas taken to the 0.7 exponential power, assuming the same continuous baseflow contribution of 600 cfs from Sebago Lake. The resulting peak discharges exceeded those values of the “Floodplain Information, Presumpscot River Study” U.S. Army Corps of Engineers (USACE 1975a), by approximately 20 percent, due mainly to the inclusion of the significant March 1977 event in the discharge-frequency analysis.

It was found that water levels along Mill Brook were nearly equal to those near the mouth and the lower portion of the Scarborough River. Calculated storm levels decreased approximately three-fourths of a foot in the upper portions of the Scarborough, Dunstan, and Nonesuch Rivers. The calculations made above neglected any freshwater inflow at the upstream boundary of the Scarborough and Nonesuch Rivers. However, both these rivers drain a substantial area, and a second set of calculations was made, which included freshwater inflow of 2,000 cfs at the upstream boundary of both rivers. This flow value was taken from a study by USDA NRCS and corresponds roughly to the 1-percent-annual-chance flood (USDA NRCS 1975a). The addition of freshwater inflow indicated the flood level in the upper portions of the Scarborough and Nonesuch Rivers to be approximately one-fourth of a foot less than the level at the open coast.

The freshwater inflow quantity of 2,000 cfs is based on calculations that are only approximate. Nevertheless, it can be inferred from the results of the modeling that the flood elevation throughout the estuary portion of the Scarborough River-Nonesuch River system is essentially uniform.

There being no discharge records for either Mill Brook or Minnow Brook in Westbrook, the runoff characteristics of the watersheds were assumed to be equivalent to those for the lower Presumpscot River basin as a whole, and flows were determined on a direct drainage area relationship. In the case of Mill Brook, the additional effect of storage at Highland Lake (Town of Falmouth) in the upper watershed was also considered in the selection of peak flows from the lower 4.5 square mile drainage area. Several significant flood events were recently recorded on the Stroudwater River by USGS, suggesting the need for some modification of the discharge-frequency relationship previously published

in the “Flood Hazard Analysis Stroudwater River Study” (USDA NRCS 1975b). The discharges developed by USDA NRCS for the 1-percent-annual-chance frequency flood were retained, but values in the more frequent range were increased due to the recent frequency of high flows, particularly the events of April 1975, April 1976, and March 1977. Discharges for the ungaged Clark Brook and Tributary to Clark Brook were established on the basis of the Stroudwater River discharge-frequency curve, making appropriate adjustments for differences in drainage areas.

In Standish, computation of flow past the hydropower plant at West Buxton in York County was the principal source of data for defining discharge-frequency relationships for the Saco River and the Saco River Left Channel (FEMA 1980e). Records of annual maximum dai1y discharge were furnished by the Central Maine Power Company. These discharges were computed from records of flow over dam, through gates, and through wheels of the power plant. The data covers a period of 64 years (1908 to 1916 and 1920 to 1977).

Values of the 10-, 2-, 1-, and 0.2-percent-annual-chance peak discharges for Saco River and Saco River Left Channel in Standish were obtained from a log-Pearson Type III distribution of these annual maximum daily flow data (WRC 1977). The results from this analysis were increased by 1.7 percent to simulate instantaneous peak discharge. The 1.7 percent factor was determined to be the average amount by which instantaneous peak flows exceeded concomitant daily flows at West Buxton and was based on a comparison of 59 events. The instantaneous peak discharges were computed from flow through wheels and gates and flow over spillways. Because of the difference in drainage area from West Buxton (1,571 square miles) to the Buxton-Standish-Limington Town line (1,330 square miles), further adjustments in the peak flows were required to estimate flow at various points along the studied reach.

USGS has kept discharge records of the Saco River at Cornish, Maine (station no. 01066000) since 1916. The drainage area at Cornish is 1,298 square miles. The adjusted flows for the Saco River used in this report were prorated values based on the difference in drainage area between Cornish and West Buxton.

At the southern corporate limits of Standish, the Saco River is divided into two channels, the Saco River and the Saco River Left Channel. The total discharge is divided between the two channels. The Bonny Eagle Hydrologic Dam on the Saco River limits the maximum discharge that will be carried by the Saco River and, through the use of a rating curve, the maximum discharge that the Bonny Eagle Hydrologic Dam can carry was determined to be 4,000 cfs. A maximum discharge of 4,000 cfs was used for all floods for the Saco River, and the remaining discharge was routed through the Saco River Left Channel.

The drainage area for the Presumpscot River at Cumberland Mills Dam and at Westbrook-Falmouth Boundary is 436 square miles above Sebago Lake. The drainage area for Mill Brook at its mouth is 7.9 square miles above Highland Lake (Town of Falmouth).

For Windham, the principal source of data for the Presumpscot River was records published by USGS (gage no. 01064000, Presumpscot River at the outlet of Sebago

Lake, Maine, January 1887 to 1977). In addition, USGS has operated a gage at West Falmouth since 1975 (gage no. 01064140).

Countywide Analyses

For this countywide study, no new detailed riverine Hydrologic Analyses were conducted. All previously studied area were re-delineated using LiDAR information. For details, please refer to the Floodplain and Floodway information.

For this countywide study, all existing approximate analysis reaches were restudied by approximate methods by Atkins in 2013 (Atkins 2013) and Ransom Consulting Engineers and Scientists in 2012 (Ransom 2012). For the Atkins study, the discharges were computed using the SCS TR20 method using Runoff Curve numbers. The reaches covered all existing pre-countywide study reaches.

In the Town of Falmouth, Meader Brook, West Branch Piscataqua, and East Branch of Piscataqua were studied by approximate methods by Ransom Consulting Engineers and Scientists (Ransom 2012). Discharges were calculated using the SCS TR20 method using Runoff Curve numbers and Times of Concentrations for subwatersheds, using 1- percent-annual-chance rainfall distribution for a 24-hour storm. Non-steady flow simulations were used to account for storage and timing differences of peak passage within the watershed. The Cornell University “Extreme Precipitation in New York and New England” website (Cornell 2012) was accessed in 2012 to obtain the 1-percent- annual-chance, 24-hour rainfall.

A summary of the discharges is provided in Table 10. Frequency Discharge-Drainage Area Curves used to develop the hydrologic models may also be shown in Figure 7 for selected flooding sources. A summary of stillwater elevations developed for non-coastal flooding sources is provided in Table 11. (Coastal stillwater elevations are discussed in Section 5.3 and shown in Table 17.) Stream gage information is provided in Table 12.

Table 10: Summary of Discharges

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance At the water quality monitoring station Androscoggin near the State 3,410 65,390 * 93,390 106,960 * 143,070 River Route 201 bridge in Brunswick Confluence of Saco Breakneck Brook 5.5 615 * 1,095 1,350 * 2,075 River At 0.9 mile upstream of Breakneck Brook 4.4 550 * 950 1,225 * 1,900 confluence with Saco River At 1.6 miles upstream of Breakneck Brook 3.6 475 * 850 1,100 * 1,730 confluence with Saco River At 3.5 miles Breakneck Brook upstream of Saco 1.4 340 * 630 795 * 1,320 River At its confluence Capisic Brook 5.09 620 * 890 1,020 * 1,310 with the Fore River At upstream of Capisic Brook confluence of 2.78 539 * 804 935 * 1,337 Nasons Brook At Essex Road Capisic Brook (extended) in 1.92 498 * 724 835 * 1,075 Portland *Not calculated for this Flood Risk Project

60 Table 10: Summary of Discharges • continued

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance At mouth in Clark Brook 1.02 295 * 350 375 * 515 Westbrook Colley Wright Downstream of 3.8 * * * 5,420 * * Brook Chute Road At the confluence Collyer Brook with the Royal River 19.63 1,400 * 2,250 2,630 * 3,750 (Upstream) At Merrill Road in Collyer Brook 19.09 1,350 * 2,180 2,550 * 3,640 Gray At Megquier Road in Collyer Brook 14.49 940 * 1,610 1,860 * 2,890 Gray At U. S. Route 202 Collyer Brook 13.75 870 * 1,480 1,750 * 2,530 in Gray At Mayall Road in Collyer Brook 9.31 700 * 1,100 1,280 * 1,820 Gray At Weymouth Road Collyer Brook 8.51 630 * 1,000 1,160 * 1,640 in Gray At the Maine Collyer Brook 6.78 490 * 770 890 * 1,260 Turnpike in Gray At State Route 26 in Collyer Brook 3.18 190 * 300 340 * 470 Gray At North Raymond Collyer Brook 1.81 80 * 120 130 * 170 Road in Gray At Main Street in Corn Shop Brook 0.67 90 * 190 290 * 900 Bridgton *Not calculated for this Flood Risk Project

61 Table 10: Summary of Discharges • continued

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance At 540 feet above Crooked River confluence with the 151.5 6,100 * 9,500 11,000 * * Songo River At upstream Casco Crooked River 147.5 6,100 * 9,500 11,000 * 14,800 corporate limits Crooked River At the upstream of (Town Of Scribner's Mill in 107.6 6,200 * 9,700 11,200 * 14,500 Harrison) Harrison At the downstream Crooked River of Norway (Oxford (Town Of 95.6 6,300 * 9,700 11,200 * 14,500 County)/Harrison Harrison) corporate limits At State Routes 35 Crystal Lake & 117 bridge over 8.7 40 * 95 125 * 290 Brook Crystal Lake Brook At crossing of Ditch Brook Varney's Mill Road 20.3 535 * 821 988 * 1,380 in Windham At outlet of Little Ditch Brook 18.9 535 * 821 988 * 1,380 Sebago Lake At the Confluence Dug Hill Brook 3.2 315 * 560 700 * 1,130 with Saco River East Branch At its confluence 0.35 191 * 315 370 * 521 Capisic Brook with Capisic Brook At the confluence Eddy Brook 4.29 190 * 360 450 * 710 with Collyer Brook Near its confluence Fall Brook 1.5 1,070 * 1,453 1,619 * 2,287 with Back Cove 1.54 *Not calculated for this Flood Risk Project

62 Table 10: Summary of Discharges • continued

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance Upstream of Fall Brook Washington Avenue 1.271.3 886 * 1,197 1,331 * 1,891 in Portland At Ray Street in Fall Brook 1.0 681 * 900 996 * 1,416 Portland 1.00 At upstream of Red Jackson Brook 3.5 320 * 490 580 * 780 Brook At Gorham Road in Jackson Brook 2.8 230 * 370 440 * 610 South Portland At pipeline crossing Jackson Brook 2.6 170 * 300 360 * 530 in South Portland At Foden Road in Jackson Brook 2.2 150 * 250 310 * 470 South Portland Little Sebago At its outlet 18.9 100 * 130 140 * 180 Lake At its confluence Long Creek 8 500 * 770 900 * 1,220 with the Fore River At downstream of Long Creek 6.9 450 * 700 840 * 1,150 Red Brook Mill Brook At mouth 4.5 480 * 630 700 * 860 At crossing of Milliken Brook 0.5 * * * 350 * * Anderson Road Minnow Brook At mouth 1.3 340 * 460 520 * 660 North Branch Above confluence 12.0 1,070 * 1,650 1,930 * 2,630 Little River with Branch Brook *Not calculated for this Flood Risk Project

63 Table 10: Summary of Discharges • continued Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance At Upstream of the Nasons Brook confluence of 1.43 180 * 270 330 * 440 Capisic Brook At Near Portland Nasons Brook Terminal Railroad 1.15 125 * 195 225 * 310 culvert in Portland At the Confluence Pigeon Brook 4.3 570 * 1,005 1,250 * 2,000 with Saco River At the Confluence of Pigeon Brook Pigeon Brook 1.4 285 * 510 640 * 1,040 Tributary Pigeon Brook At the Confluence 2.9 325 * 580 725 * 1,170 Tributary with Pigeon Brook At the confluence Piscataqua River with the 41.2 2,020 * 3,220 3,850 * 5,380 Presumpscot River At upstream of the Piscataqua River East Branch 21 1,170 * 1,910 2,310 * 3,290 Piscataqua River At upstream of the Tributary which Piscataqua River flows through the 19.6 1,120 * 1,830 2,210 * 3,150 corner of West Falmouth At State Route 100 Piscataqua River 18.6 1,070 * 1,750 2,210 * 3,010 in Falmouth *Not calculated for this Flood Risk Project

64 Table 10: Summary of Discharges • continued

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance At the downstream Pleasant River Gray corporate 13.68 1,210 * 1,990 2,280 * 3,150 limits At Lawrence Road Pleasant River 12.3 1,140 * 1,900 2,180 * 3,030 in Gray At Windham Center Pleasant River 5 520 * 860 980 * 1,360 Road in Gray At Hunts Hill Road Pleasant River 4.72 500 * 830 950 * 1,310 in Gray Presumpscot At Martin Point 638.1 9,800 * 13,600 15,300 * 19,700 River Bridge in Falmouth At downstream of Presumpscot the confluence of 632.2 9,800 * 13,600 15,300 * 19,700 River the Piscataqua River At upstream of the Presumpscot confluence of the 590.9 9,300 * 12,900 14,500 * 18,600 River Piscataqua River At the Gorham-City Presumpscot of Westbrook 574 8,500 * 11,800 13,300 * 17,000 River corporate limits At the Windham-City Presumpscot of Westbrook 574 8,500 * 11,800 13,300 * 17,000 River boundary Presumpscot At the confluence of 516 6,500 * 9,200 10,800 * 15,200 River Little River Presumpscot Above mouth of the 516 6,500 * 9,200 10,800 * 15,200 River Little River *Not calculated for this Flood Risk Project

65 Table 10: Summary of Discharges • continued

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance Presumpscot At the Little Falls 508 6,000 * 8,200 10,000 * 14,000 River Dam in Gorham Presumpscot At Newhall Dam 502 5,870 * 8,020 9,780 * 13,700 River At above mouth of Presumpscot Pleasant River in 452 2,740 * 4,940 6,210 * 10,200 River Gorham Presumpscot At Eel Weir Dam in 441 2,690 * 4,840 6,090 * 10,000 River Gorham Presumpscot At the Windham- 437 1,980 * 4,130 5,380 * 9,290 River Standish boundary Presumpscot At Westbrook- 154 9,300 * 12,900 14,500 * 18,600 River Falmouth Boundary Presumpscot At Cumberland Mills 134 8,500 * 11,800 13,300 * 17,000 River Dam At the Confluence Quaker Brook 12.5 830 * 1,390 1,695 * 2,880 with Saco River At its confluence Red Brook 3.4 210 * 350 430 * 620 with Jackson Brook At Maine Turnpike Red Brook 3.2 190 * 320 390 * 560 exit ramp At the upstream Red Brook South Portland 2.8 160 * 280 340 * 490 corporate limits At the Gray Royal River downstream 72.76 3,390 * 4,670 5,310 * 7,170 (Upstream) corporate limits *Not calculated for this Flood Risk Project

66 Table 10: Summary of Discharges • continued

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance Royal River At Depot Road in 69.12 3,270 * 4,570 5,220 * 7,110 (Upstream) Gray Royal River At the Main Central 48.99 2,650 * 3,750 4,310 * 5,940 (Upstream) Railroad in Gray At the Gray Royal River upstream corporate 48.35 2,610 * 3,710 4,270 * 5,890 (Upstream) limits Royal River At Morse Road in 48.3 2,610 * 3,710 4,270 * 5,940 (Upstream) New Gloucester Royal River At Penny Road in 45.13 2,450 * 3,530 4,060 * 5,890 (Upstream) New Gloucester Royal River At State Route 231 38.1 2,100 * 3,110 3,620 * 5,090 (Upstream) in New Gloucester At Canadian Royal River National Railroad in 29.15 1,320 * 2,090 2,460 * 3,580 (Upstream) New Gloucester At Cobbs Bridge Royal River Road in New 28.46 1,270 * 2,020 2,390 * 3,490 (Upstream) Gloucester At the New Royal River Gloucester 26.07 1,110 * 1,810 2,150 * 3,190 (Upstream) upstream corporate limits At the North Royal River Yarmouth 136.4 6,490 * 8,930 10,170 * 13,900 (Upstream) downstream corporate limits *Not calculated for this Flood Risk Project

67 Table 10: Summary of Discharges • continued Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance Royal River At State Route 9 in 131.96 6,540 * 8,850 10,020 * 13,820 (Upstream) North Yarmouth Royal River At State Route 231 77.67 3,560 * 4,800 5,420 * 7,250 (Upstream) in North Yarmouth Royal River At Mill Road in North 73.84 3,430 * 4,700 5,330 * 7,190 (Upstream) Yarmouth At the North Royal River Yarmouth upstream 72.76 3,390 * 4,670 5,310 * 7,170 (Upstream) corporate Limits Royal River At USGS gage No. 142 6,085 * 9,060 10,530 * 14,540 (Downstream) 010600000 At Bonny Eagle Saco River 1,560 25,300 * 37,700 43,800 * 60,600 Dam At the Hollis- Saco River Limington-Standish 1,550 25,200 * 37,500 43,600 * 60,200 corporate limits At the upstream Saco River confluence of Little 1,352 23,600 * 34,600 39,800 * 53,800 Ossipee River At the Baldwin Saco River 1,340 23,590 * 34,560 39,835 * 53,755 corporate limits At the Baldwin- Saco River Limington-Standish 1,330 23,600 * 34,600 39,800 * 53,800 corporate limits At the confluence of Saco River 1,313 23,065 * 33,790 38,950 * 52,560 Pigeon Brook *Not calculated for this Flood Risk Project

68 Table 10: Summary of Discharges • continued

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance Saco River And At the Buxton-Hollis- Saco River Left Standish corporate 1,560 25,400 * 37,900 40,000 * 61,000 Channel limits At 5,000 feet upstream of Songo River 292 6,300 * 10,000 11,500 * 15,200 confluence with Sebago Lake At downstream of Songo River 270.9 6,300 * 10,000 11,500 * 15,200 Songo Locks Dam At Smith Avenue in Stevens Brook 41.95 1,440 * 2,590 3,070 * 4,380 Bridgton At 1,100 feet Stevens Brook upstream of Depot 41 1,410 * 2,520 2,910 * 3,670 Street in Bridgton At 75 feet upstream Stevens Brook of Beacon Street in 20.67 330 * 620 740 * 1,320 Bridgton Stroudwater River At Mouth 27.7 2,960 * 3,540 3,760 * 5,200 At the upstream Stroudwater River Portland corporate 27.2 1,885 * 3,100 3,735 * 5,160 limits At Spring Street Stroudwater River 25.1 2,760 * 3,310 3,510 * 4,860 Bridge in Westbrook At Libby Road in Thayer Brook 5.58 520 * 900 1,050 * 1,500 Gray At U.S. Route 202 in Thayer Brook 3.24 300 * 540 630 * 920 Gray *Not calculated for this Flood Risk Project

69 Table 10: Summary of Discharges • continued Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance Approximately 800 Tributary 1 to feet downstream of Presumpscot 330 * * * 380 * * Standish Corporate River Limes Tributary 1 to Approximately 250 Presumpscot feet upstream of 500 * * * 210 * * River community limits Just downstream of Tributary 1 to confluence with Presumpscot 430 * * * 176 * * Tributary 2 to River Presumpscot River 370 feet upstream Tributary 1 to of confluence with Presumpscot 178 * * * 92 * * Tributary 2 to River Presumpscot River Approximately 1,600 Tributary 1 to feet upstream of Presumpscot confluence with 178 * * * 176 * * River Tributary 2 to Presumpscot River Just downstream of Tributary 2 to confluence with Presumpscot 430 * * * 176 * * Tributary 1 to River Presumpscot River Approximately 2,200 Tributary 2 to feet upstream of Presumpscot confluence with 251 * * * 87 * * River Tributary 1 to Presumpscot River *Not calculated for this Flood Risk Project

70 Table 10: Summary of Discharges • continued Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance At Farm Road in Tributary A 0.95 90 * 160 190 * 270 Gray Tributary To Clark At mouth 0.45 165 * 200 210 * 290 Brook At its confluence Trout Brook 2.6 290 * 440 510 * 690 with the Fore River At upstream of Trout Brook 2 210 * 330 390 * 530 Kimball Brook At Fessenden Trout Brook Avenue in South 1.8 170 * 270 320 * 450 Portland At Sawyer Street in Trout Brook 1.7 120 * 220 270 * 390 South Portland At the Cape Elizabeth/South Trout Brook 1.3 94 * 170 200 * 310 Portland corporate limits At Spurwink Avenue Trout Brook in Cape Elizabeth 1 85 * 150 180 * 270 and South Portland Unnamed 2,000 feet upstream Tributary To Rich of Maine Central 0.32 * * * 51 * * Mill Brook Railroad Unnamed 2,800 feet upstream Tributary To of Maine Central 0.37 * * * 43 * * Tucker Brook Railroad West Branch At its confluence 0.56 340 * 447 485 * 601 Capisic Brook with Capisic Brook *Not calculated for this Flood Risk Project

71 Table 10: Summary of Discharges • continued

Peak Discharge (cfs) Drainage Area (Square 10% Annual 4% Annual 2% Annual 1% Annual 1% Annual 0.2% Annual Flooding Source Location Miles) Chance Chance Chance Chance Chance Future Chance Westcott Brook At mouth 3.06 359 * 578 684 * 956 At the confluence Willett Brook 20.21 1,350 * 2,440 2,890 * 4,130 with Stevens Brook At Willet Road in Willett Brook 19.9 1,330 * 2,400 2,850 * 4,070 Bridgton

*Not calculated for this Flood Risk Project

Figure 7: Frequency Discharge-Drainage Area Curves [Not Applicable to this Flood Risk Project]

Table 11: Summary of Non-Coastal Stillwater Elevations

Elevations (feet NAVD88)

10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flooding Source Location Chance Chance Chance Chance Chance Bay Of Naples Town of Naples 272.6 * 273.6 273.8 274.5 Bonny Eagle Pond Town of Standish * * * 268.4 * Collins Pond Town of Windham 271.4 * 271.8 272.0 272.4 Cresent Lake Entire shoreline 277.7 * 278.3 278.4 278.6 Crystal Lake (Town of Entire shoreline 311.6 * 311.7 311.8 311.9 Gray) Crystal Lake (Town of Entire shoreline 298.3 * 399.3 299.4 300.6 Harrison)

*Not calculated for this Flood Risk Project

72 Table 11: Summary of Non•Coastal Stillwater Elevations • continued Elevations (feet NAVD88)

10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flooding Source Location Chance Chance Chance Chance Chance Forest Lake Entire shoreline * * * 278.2 * Highland Lake (Town of Town of Bridgton 426.8 * 427.2 427.3 427.7 Bridgetown) Highland Lake (Town of Town of Falmouth 192.0 * 192.5 192.7 193.1 Falmouth) Little Sebago Lake Entire shoreline 286.5 * 286.9 287.0 287.4 Long Lake Town of Naples 272.6 * 267.0 267.1 267.4 Entire shoreline Long Lake 272.6 * 273.4 273.8 274.5 within Bridgton Entire shoreline Long Lake 272.6 * 273.4 273.8 274.5 within Harrison Mill Pond Town of Windham 283.5 * 284.4 284.8 285.8 At Outlet in Town of Panther Pond 277.7 * 278.3 278.4 278.6 Raymond Pettingill Pond Town of Windham * * * 278.2 * At outlet in the Town Sebago Lake of Standish, and the 266.7 * 267.0 267.1 267.4 Town of Windham

*Not calculated for this Flood Risk Project

Table 12: Stream Gage Information used to Determine Discharges

Agency Drainage Period of Record that Area Flooding Gage Maintains (Square Source Identifier Gage Site Name Miles) From To Presumpscot Presumpscot 01064000 USGS N/A 1887 1977 River River West Presumpscot 01064140 USGS Falmouth, N/A 1975 1977 River ME Royal River Yarmouth, 01060000 USGS N/A 30 years (downstream) ME Saco River 01066000 USGS Cornish, ME N/A 60 years

5.2 Hydraulic Analyses Analyses of the hydraulic characteristics of flooding from the sources studied were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Base flood elevations on the FIRM represent the elevations shown on the Flood Profiles and in the Floodway Data tables in the FIS Report. Rounded whole-foot elevations may be shown on the FIRM in coastal areas, areas of ponding, and other areas with static base flood elevations. These whole-foot elevations may not exactly reflect the elevations derived from the hydraulic analyses. Flood elevations shown on the FIRM are primarily intended for flood insurance rating purposes. For construction and/or floodplain management purposes, users are cautioned to use the flood elevation data presented in this FIS Report in conjunction with the data shown on the FIRM. The hydraulic analyses for this FIS were based on unobstructed flow. The flood elevations shown on the profiles are thus considered valid only if hydraulic structures remain unobstructed, operate properly, and do not fail.

Pre-countywide Analyses

Analyses of the hydraulic characteristics of the flooding sources studied in detail were carried out to provide estimates of the elevations of floods of the selected recurrence intervals along each flooding source.

Elevations on Long Lake were obtained through a log-Pearson Type III method of analysis (WRC 1977) of 40 years of stage-storage records at the Songo Locks in Naples, Maine (FEMA 1981c). The Water Surface Profile (WSP) WSP-2 program was used to compute water-surface profiles from the Songo Locks to the Bay of Naples on which the same elevation as Long Lake is maintained (USDA NRCS 1976).

Elevations on Crystal Lake (Town of Harrison) were taken directly from the results of the USDA NRCS TR-20 hydrologic evaluation (USDA NRCS 1965), which uses known discharge-elevation relationships to route floods through dams.

In Baldwin, starting water-surface elevations for all streams were calculated using the slope-area method. Water-surface elevations of floods of the selected recurrence intervals were computed through the use of the USACE HEC-2 step-backwater computer program (USACE 1978). Flood profiles were drawn showing computed water- surface elevations for floods of the selected recurrence intervals. The approximate zone on Pigeon Brook Tributary above Chase Siding Road was determined using the 1- percent-annual-chance brook elevation. The flood above Chase Siding Road was assumed to be a level backwater at that elevation.

In Bridgton, water-surface elevations of floods of the selected recurrence intervals were computed using the USDA NRCS WSP-2 computer program (FEMA 1981a and USDA NRCS 1976).

Elevations for the streams studied by detailed methods were started from critical depth calculations at the old Central Maine Power Company dam downstream of Kansas Road.

Water-surface elevations on Long Lake and Highland Lake (Town of Bridgetown) were obtained through a log-Pearson Type III method using 40 years of stage-storage records at the Songo Locks in Naples (FEMA 1981c and WRC 1977). The WSP-2 program was used to compute water-surface profiles from the Songo Locks to the Bay of Naples, which maintains the same elevation as Long Lake.

Water-surface elevations of floods of the selected recurrence intervals were computed using the USACE HEC-2 step-backwater computer program (USACE 1978). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Starting water-surface elevations for the Androscoggin River were calculated using the mean high tide for Merrymeeting Bay.

In Cape Elizabeth, water-surface elevations of floods of the selected recurrence intervals were computed using the USACE HEC-2 step-backwater computer program (USACE 1978). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Starting water-surface elevations for Trout Brook were obtained from the FIS for the City of South Portland (FEMA 1984d).

In Casco, water-surface elevations for the selected recurrence intervals on the Songo River and Crooked River were computed by the USDA NRCS WSP-2 computer program (USDA NRCS 1976), starting from critical depth at Sebago Lake.

In Falmouth water-surface elevations of floods of the selected recurrence intervals were computed through the use of the USACE HEC-2 step-backwater computer program (USACE 1978). Starting water-surface elevations for the Presumpscot River were based on the mean tide elevation. Starting water-surface elevations for the Piscataqua River were calculated using the slope/area method.

At various locations along the Presumpscot and Piscataqua Rivers, the analysis indicates that flow would be supercritical flow. Because of the inherent instability of supercritical flow, critical depth was assumed at those locations when establishing the profile elevations for this study.

In Gorham, water-surface elevations of floods of the selected recurrence intervals were computed through the use of the USGS E431 step-backwater computer program (USGS 1976b). Starting water-surface elevations for the profile determination of the Presumpscot River were taken from the FIS for the City of Westbrook (FEMA 1980f). These elevations were verified by ratings developed for flow over dams. Starting elevations upstream of each of the four dams were determined from the stage-discharge relationships, which USGS computed. USGS made direct readings of the pond elevations upstream from the dams, surveyed the dams, and recorded their physical dimensions. Reference points were set in the forebays of the dams so the head on the dams could be computed for observed and measured flows.

Current meter measurements were made to determine the flow of the Presumpscot River at each of the dams. A relationship between stages and discharges was made for each. These ratings were extended on the basis of the standard flow over dam formula (Francis Formula, Q = CLH 3/2) (Francis, J.B. 1909). The discharge is Q, C is the coefficient of discharge, L is the length of the dam perpendicular to the direction of the flow, and H is the head of the dam.

The coefficient of discharge was determined using the tables and graphs presented in a USGS publication, which lists “C” values for various dam types (USGS 1968). The actual “C” value used in the Francis Formula to compute the flood elevation was based on both of these “C” determinations. Ratings were verified by historic flood elevations.

For the streams studied by approximate methods in Gorham, the 1-percent-annual- chance flood elevations were estimated using the regional stage-frequency relationship by USGS hydrologists at the Augusta, Maine, office (FEMA 1981f). This relationship indicates that the 1-percent-annual-chance flood is about 10 feet higher than the stream elevation mapped on USGS topographic maps.

In Gray, water-surface elevations for the selected recurrence intervals were computed by the TR-20 model for Little Sebago Lake and Crystal Lake (Town of Gray), and by the USDA NRCS WSP-2 computer program for each of the streams studied in detail (USDA NRCS 1976 and USDA NRCS 1965).

Starting water-surface elevations for the Royal River (upstream) in Gray were determined using a critical depth elevation at a dam immediately below Elm Street, downstream in the Town of Yarmouth. The Collyer Brook starting water-surface elevations were a continuation of the Royal River (upstream) water-surface profile. The Pleasant River starting water-surface elevations were determined using critical depth taken downstream in the Town of Windham. The starting water-surface elevations for Eddy Brook are a continuation of the water-surface profile of Collyer Brook. Thayer Brook starting water-surface elevations are a continuation of the water-surface profiles of the Pleasant River; the starting elevations for Tributary A are a continuation of the water- surface profile for Thayer Brook.

In Harrison, water-surface elevations for the selected recurrence intervals were computed by the USDA NRCS WSP-2 computer program (USDA NRCS 1976). The water-surface profiles for the Crooked River (Town of Harrison) were continued from the FIS for Naples (FEMA 1981c). The water-surface elevation of Long Lake was used as the starting water-surface elevation for Crystal Lake Brook.

In Naples, water-surface elevations for the selected recurrence intervals on Sebago Lake were furnished by USGS. USGS determined the water-surface elevations by using 40 years (1920 to 1960) of gaging station information from the Sebago Lake dam gage. Water-surface elevations for the Bay of Naples, Long Lake, and the Songo River above Songo Lock were computed through the use of a log-Pearson Type III analysis (WRC 1967) on 40 years of records, 1920 to 1960, from the Songo Lock gaging station.

In Naples, water-surface elevations for the Songo River and Crooked River were computed through the use of the USDA NRCS WSP-2 computer program starting from critical depth at Sebago Lake (USDA NRCS 1976).

In New Gloucester, water-surface elevations of floods of the selected recurrence intervals were computed through the use of the USDA NRCS WSP-2 computer program (USDA NRCS 1976). Critical depth at a dam downstream in the Town of Yarmouth was assumed as starting water-surface elevations for the Royal River (upstream).

In North Yarmouth, water-surface elevations of floods of the selected recurrence intervals were computed using the USDA NRCS WSP-2 computer program (USDA NRCS 1976). Starting water-surface elevations for the Royal River (upstream) were started from critical depth at a dam immediately below Elm Street, downstream in the Town of Yarmouth.

In Portland, for the 1986 FIS, water-surface elevations of floods of the selected recurrence intervals were computed using the USACE HEC-2 step-backwater computer program (USACE 1978). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Starting water-surface elevations for the Presumpscot River were obtained from the previous FIS for the Town of Falmouth (FEMA 1984a). Starting water-surface elevations for the Stroudwater River, Capisic Brook, and Nasons Brook were determined using the mean tide elevation.

For the 1992 Portland revision, water-surface elevations of floods of the selected recurrence intervals were computed for Capisic Brook, East Branch Capisic Brook, and West Branch Capisic Brook, using the NRCS WSP-2 step-backwater computer program (USACE 1978 and USDA NRCS 1976).

Delineation of flooding for small portions of Mackworth and Hope Islands was taken from the FlSs for the Towns of Falmouth and Cumberland, respectively (FEMA 1984a and FEMA 1985b).

In Sebago, analyses of elevations of Sebago Lake were based on 106 years (1872 to 1977) of lake stage data furnished by the S.D. Warren Company of Westbrook, Maine.

In South Portland, water-surface elevations of floods of the selected recurrence intervals were computed using the USACE HEC-2 step-backwater computer program (USACE 1978). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Flooding from Long Creek was found to be completely controlled by tidal flooding from the Fore River. Starting water-surface elevations for Long Creek, Jackson Brook, and Trout Brook were based on mean high

77 tide elevations. Starting water-surface elevations for Red Brook were taken at its confluence with Jackson Brook, assuming coincident peaks.

In Standish, water-surface elevations for the selected recurrence interval floods were computed through use of the USGS E431 step-backwater computer program (USGS 1976b) The starting water-surface elevations used for the Saco River and the Saco River Left Channel profile determination were taken from the FIS for the adjacent community of Buxton (FEMA). The starting elevations upstream of Bonny Eagle Power Station were determined from a spillway discharge rating furnished by Central Maine Power Company. This rating is a stage discharge table that gives flows for peak discharges, including an allowance for water passing the plant while normal power is being generated. Peak discharges obtained were in agreement with flows obtained at the USGS gaging station on the Saco River at Cornish, Maine (station no. 00106600) after an allowance for inflow was made. There is a difference in drainage area of only 262 square miles between the reservoir and gage.

In Westbrook, starting water-surface elevations were determined for the Stroudwater River and the Presumpscot River using previously published elevation discharge relationships (FEMA 1980f). Starting water-surface elevations for Minnow Brook and Mill Brook were determined at their respective mouths at the Presumpscot River. Starting water-surface elevations for Clark Brook were determined at its confluence with the Stroudwater River. Starting water-surface elevations for Tributary to Clark Brook were determined at its confluence with Clark Brook. Flood profiles were computed for all the streams using USACE’s HEC-2 computer program (USACE 1978). Flood profiles were drawn showing computed water-surface elevations to an accuracy of 0.5 foot for floods of the selected recurrence intervals (Exhibit 1).

In Windham, water-surface elevations of floods of the selected recurrence intervals were computed through the use of the USGS E431 step-backwater computer program (USGS 1976b). The starting water-surface elevations used for the profile determination of the Presumpscot River were taken from the FIS for the City of Westbrook (FEMA 1980f). These elevations were verified by ratings developed for flow over dams. Starting water- surface elevations upstream of each of the four dams on the Presumpscot River and upstream of the three dams on Ditch Brook were determined from stage-discharge relationships. For the stage-discharge relationships, USGS personnel made direct readings from the dams, surveyed the dams, and recorded their physical dimensions. Reference points were set in the forebays of the dams so the head on the dams could be computed for observed and measured flows.

Furnished records of discharge measurements or current-meter measurements were made to determine the flow of the streams at each of the dams. These ratings were extended on the basis of the standard flow over dam formula (Francis Formula, Q = CLH3/2) (Francis, J.B. 1909). The discharge being studied is Q, C is the coefficient of discharge, L is the length of the dam perpendicular to the direction of the flow, and H is the head on the dam.

The coefficient of discharge was also determined using the tables and graphs in a USGS publication that lists “C” values for various dam types (FEMA 1981h). The actual “C” value used in the Francis Formula to compute the flood elevations was based on both of these “C” determinations. Ratings were verified by historic flood elevations.

In the area of Elm Street on the Royal River (downstream) in Yarmouth, there is a diversionary channel bypassing the main dam below the Main Street Bridge. A divided flow analysis was performed between the diversion and the main channel by equalizing head losses over the divided flow region. The diversion carries a small percentage of the total discharge and, therefore, the water-surface elevations on the main channel are only slightly affected by including a divided flow analysis.

At various locations along the Royal River (downstream), the analysis indicates that flow would be supercritical. Because of the inherent instability of supercritical flow, critical depth was assumed at those locations when establishing the profile elevations for this study.

The overbank portions of the cross section data for the Androscoggin River, Presumpscot River, Piscataqua River, Saco River, Saco River Left Channel, Royal River (downstream), Songo River, Highland Lake (Town of Falmouth) and Trout Brook were obtained from topographic maps compiled from aerial photographs (USACE 1975b, J.W. Sewall 1979a through 1979c, USACE 1970, and Hansa 1978b). The below-water sections were obtained by field measurement. Cross sections were located at close intervals above and below bridges in order to compute the significant backwater effects of these structures. In long reaches between structures, appropriate valley cross sections were also surveyed. All bridges and culverts were field surveyed to obtain elevation data and structural geometry.

Cross sections for the Crooked River and Crooked River (Town of Harrison) were obtained from aerial photographs (USDA NRCS 1971). The below-water sections, bridges, dams, and culverts were obtained from field surveys.

Cross sections for the backwater analyses in Falmouth were located at close intervals above and below bridges in order to compute the significant backwater effects of these structures. In long reaches between structures, appropriate valley cross sections were also surveyed.

Cross sections on Crystal Lake Brook were obtained from field surveys.

Cross section data in New Gloucester were obtained from field surveys. All bridges and culverts were field surveyed to obtain elevation data and structural geometry.

Overbank portions of cross section data in Portland were obtained from topographic maps (J.W. Sewall 1979d); below-water sections were obtained by field survey. Cross sections were located at close intervals above and below bridges in order to compute the significant backwater effects of these structures. In long reaches between structures, appropriate valley cross sections were also surveyed.

Cross sections for the backwater analysis of Ditch Brook were obtained using maps based on aerial photographs at a scale of 1"=800 feet (Hansa 1978b). The below-water sections were obtained by field measurement. All bridges, dams, and culverts were field checked to obtain elevation data and structural geometry.

Countywide Analyses

For this countywide revision, no new detailed riverine Hydraulic Analyses were conducted. All previously studied area were re-delineated using LiDAR information. For details, please refer to the Floodplain and Floodway information.

All existing approximate analysis reaches were restudied by approximate methods by Atkins in 2013 (Atkins 2013) and Ransom Consulting Engineers and Scientists in 2012 (Ransom 2012). In the Town of Falmouth, Meader Brook, West Branch Piscataqua, and East Branch of Piscataqua were studied by approximate methods by Ransom Consulting Engineers and Scientists (Ransom 2012). All other reaches were studied by Atkins. For both studies, HEC-RAS (USACE 2012) was used to determine the extent of the 1-percent-annual-chance flood. Major bridges and culverts impacting storage were considered in this approach. The reaches covered all existing pre-countywide study reaches.

The Androscoggin River has been redelineated using the LiDAR elevation data obtained for the coastal analyses (Sanborn Map Company, Inc. 2006).

Based on the results of the revised coastal analysis, the backwater elevations are revised where necessary. The flooding sources of Androscoggin River, Capisic Brook, Fall Brook, Long Creek, Presumpscot River, Royal River (downstream), Stroudwater River, and Trout Brook were revised for backwater elevations.

For streams for which hydraulic analyses were based on cross sections, locations of selected cross sections are shown on the Flood Profiles (Exhibit 1). For stream segments for which a floodway was computed (Section 6.3), selected cross sections are also listed in Table 24, “Floodway Data.”

A summary of the methods used in hydraulic analyses performed for this project is provided in Table 13. Roughness coefficients are provided in Table 14. Roughness coefficients are values representing the frictional resistance water experiences when passing overland or through a channel. They are used in the calculations to determine water surface elevations. Greater detail (including assumptions, analysis, and results) is available in the archived project documentation.

Table 13: Summary of Hydrologic and Hydraulic Analyses

Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations stream gaging Approximately station on Cumberland- 1.38 miles 1980 Starting water-surface elevations Androscoggin Androscoggin USACE HEC-2 AE w/ Sagadahoc upstream of dam (redelineated calculated using the mean high River River at step-backwater Floodway county boundary in Town of 2013) tide for Merrymeeting Bay Auburn (no. Brunswick 01059000) log-Pearson 1979 Within the Town Within the Town USDA NRCS Bay of Naples Type III (redelineated AE of Naples of Naples WSP-2 analysis 2013) regional regression Douglas Hill 1978 Breakneck Confluence with analysis, USACE HEC-2 AE w/ Road in the Town (redelineated Brook Saco River USGS Open- step-backwater Floodway of West Baldwin 2013) File Report 75-292 Warren Avenue 1995 Confluence with USDA NRCS NRCS WSP-2 AE w/ regional equation developed by Capisic Brook in the City of (redelineated Fore River TR-20 step-backwater Floodway USGS Portland 2013) Approximately 1.06 miles USDA NRCS Confluence with 1978 AE w/ upstream from its discharge- based on Stroudwater River Clark Brook Stroudwater USACE HEC-2 (redelineated Floodway, confluence with frequency updates River 2013) X (Shaded) Tributary to Clark curve Brook Approximately Approximately 1,975 feet 3,800 feet 2006 Colley Wright upstream of its upstream of its N/A N/A (redelineated AE Brook confluence with confluence with 2013) Unnamed Unnamed Tributary Tributary

81 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued

Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations Approximately 100 feet 1980 AE w/ Confluence with USDA NRCS USDA NRCS Collyer Brook upstream of Park (redelineated Floodway, Stevens Brook TR-20 WSP-2 Street in Town of 2013) X (Shaded) Bridgton 1980 AE w/ Corn Shop Confluence with Park Street in the USDA NRCS USDA NRCS (redelineated Floodway, Brook Stevens Brook Town of Bridgton TR-20 WSP-2 2013) X (Shaded) Within the Town Within the Town equations 1979 Crescent Lake of Casco and of Casco and developed by N/A (redelineated AE Raymond Raymond R.A. Morrill 2013) Approximately 1.40 miles 1979 AE w/ Confluence with USDA NRCS USDA NRCS starting from critical depth at Crooked River upstream of Edes (redelineated Floodway, Songo River TR-20 WSP-2 Sebago Lake Falls Dam in the 2013) X (Shaded) Town of Naples Town of Naples Approximately Crooked River and Town of 1,200 feet 1979 USDA NRCS USDA NRCS AE, X (Town of Harrison upstream of State (redelineated TR-20 WSP-2 (Shaded) Harrison) community Route 117 in the 2013) boundary Town of Harrison 1980 Within the Town Within the Town USDA NRCS USDA NRCS Crystal Lake (redelineated AE of Gray of Gray TR-20 TR-20 2013) USDA NRCS Crystal Lake 1979 Crystal Lake Confluence with TR-20 USDA NRCS AE w/ Dam in the Town (redelineated Brook Long Lake hydrologic WSP-2 Floodway of Harrison 2013) evaluation Mill Pond Dam in 1980 AE w/ Varney’s Mill USGS E431 Ditch Brook the Town of N/A (redelineated Floodway, Dam step-backwater Windham 2013) A

82 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued

Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations Approximately regional 1,350 feet regression 1978 AE w/ Confluence with upstream from analysis, USACE HEC-2 Dug Hill Brook (redelineated Floodway, Saco River State Route 113 USGS Open- step-backwater 2013) X (Shaded) in the Town of File Report Cornish 75-292 Approximately 1,560 feet 1995 East Branch Confluence with USDA NRCS NRCS WSP-2 AE, X downstream from (redelineated Capisic Brook Capisic Brook TR-20 step-backwater (Shaded) the confluence of 2013) Capisic Brook Town of 1980 Confluence with USDA NRCS USDA NRCS AE w/ Eddy Brook Gloucester (redelineated Collyer Brook TR-20 WSP-2 Floodway corporate limits 2013) Just upstream of AE w/ Confluence with Fall Brook Allen Street in the HEC-HMS HEC-RAS 2013 Floodway, Back Cove Town of Portland X (Shaded) Within the towns Within the towns The inflow hydrograph was routed USGS of Cumberland, of Cumberland, through Pettingill Pond and Forest Forest Lake regression HEC-RAS 2001 AE Gray, and Gray, and Lake using a level pool reservoir equation Windham Windham routing technique (Chow, 1964) 1980 Within the Town Within the Town log-Pearson USDA NRCS Highland Lake (redelineated AE of Bridgton of Bridgton Type III WSP-2 2013) hydrologic 1980 Within the Town Within the Town Highland Lake routing N/A (redelineated AE at spillway of Falmouth of Falmouth methods 2013) 2009 Corporate limits Hobbs Brook Gray Road HEC-RAS HEC-RAS AE of Falmouth (redelineated 2013)

83 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations

Approximately 2006 820 feet Hobbs Brook Schuster Road HEC-RAS HEC-RAS AE upstream of (redelineated Schuster Road 2013) Approximately regional AE w/ 3,600 feet 1980 Confluence with equation USACE HEC-2 Floodway, Jackson Brook downstream of (redelineated Long Creek prepared by step-backwater A, X the Maine 2013) USGS (Shaded) Turnpike 1980 Little Sebago Within the Town Within the Town USDA NRCS USDA NRCS (redelineated AE Lake of Gray of Gray TR-20 TR-20 2013) regional 1980 Confluence of Confluence with equation USACE HEC-2 AE w/ Long Creek (redelineated Fore River Jackson Brook prepared by step-backwater Floodway 2013) USGS log-Pearson 1979 Within the Town Within the Town USDA NRCS Long Lake Type III (redelineated AE of Naples of Naples WSP-2 analysis 2013) Approximately Approximately 3,450 feet 5,525 feet 2006 Milliken Brook upstream of its upstream of its N/A N/A (redelineated AE confluence with confluence with 2013) Inkhorn Brook Inkhorn Brook no discharge records available; AE w/ runoff characteristics of the Confluence with Austin Street in direct 1978 Floodway, watersheds were assumed to be Mill Brook Presumpscot the Town of drainage area USACE HEC-2 (redelineated A, X equivalent to those for the lower River Westbrook relationship 2013) (Shaded) Presumpscot River basin as a whole.

84 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued

Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations Approximately 1.36 miles AE w/ Confluence with direct 1978 upstream of Floodway, Minnow Brook Presumpscot drainage area USACE HEC-2 (redelineated Brook Road in A, X River relationship 2013) the Town of (Shaded) Westbrook Approximately 25 regional AE w/ 1979 Confluence with feet upstream of equation USACE HEC-2 Floodway, Nasons Brook (redelineated Capisic Brook the Portland developed by step-backwater A, X 2013) Railroad Terminal USGS (Shaded) Approximately 7,000 feet 2006 AE w/ North Branch Confluence with downstream of its N/A N/A Floodway, Little River Westcott Brook (redelineated confluence with 2013) A Westcott Brook equations 1979 Within the Town Within the Town Panther Pond developed by N/A (redelineated AE of Raymond of Raymond R.A. Morrill 2013) The inflow hydrograph was routed USGS Within the Town Within the Town through Pettingill Pond and Forest Pettingill Pond regression HEC-RAS 2001 AE of Windham of Windham Lake using a level pool reservoir equation routing technique (Chow, 1964) regional Approximately 50 regression feet upstream of 1978 AE w/ Confluence with analysis, USACE HEC-2 Pigeon Brook Chase Siding (redelineated Floodway, Saco River USGS Open- step-backwater Road in the Town 2013) X (Shaded) File Report of West Baldwin 75-292

85 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued

Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations regional Upstream side of regression AE w/ 1978 Pigeon Brook Confluence with Chase Siding analysis, USACE HEC-2 Floodway, (redelineated Tributary Pigeon Brook Road in the Town USGS Open- step-backwater A, X 2013) of Baldwin File Report (Shaded) 75-292 Approximately Approximately 1,000 feet 3,625 feet 2005 Piscataqua upstream of State upstream of State N/A N/A (redelineated AE, A River Route 100 in the Route 100 in the 2013) Town of Town of Falmouth Falmouth Approximately 1,000 feet regional AE w/ Confluence with 1980 Piscataqua upstream of State equation USACE HEC-2 Floodway, Presumpscot (redelineated River Route 100 in the prepared by step-backwater A, X River 2013) Town of USGS (Shaded) Falmouth Approximately 1,400 feet AE w/ 1980 Town of Gray upstream of USDA NRCS USDA NRCS Floodway, Pleasant River (redelineated corporate limits Hunts Hill Road TR-20 WSP-2 A, X 2013) in the Town of (Shaded) Gray Town of 1980 AE w/ Discharges taken from the FIS for Presumpscot Highway 295 in drainage area USACE HEC-2 Falmouth (redelineated Floodway, the City of Westbrook and River Falmouth discharge ratio step-backwater corporate limits 2013) X (Shaded) transposed USGS Open- 1980 AE w/ USGS (gage no. 01064000, Presumpscot Within the Town Within the Town USGS E431 File Report (redelineated Floodway, Presumpscot River at the outlet of River of Windham of Windham step-backwater 75-292 2013) X (Shaded) Sebago Lake

86 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued

Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations streamflow records published by 1979 AE w/ Presumpscot Within the Town Within the Town USGS E431 USGS (station (redelineated Floodway, River of Gorham of Gorham step-backwater no. 01064000, 2013) X (Shaded) January 1887 to 1977 Gorham, 1979 AE w/ Discharges taken from the FIS for Presumpscot Standish and Highway 295 in drainage area USACE HEC-2 (redelineated Floodway, the City of Westbrook and River Windham Falmouth discharge ratio step-backwater 2013) X (Shaded) transposed corporate limits multiplying the Royal River 1978 AE w/ Presumpscot Within the City of Within the City of (downstream) USACE HEC-2 (redelineated Floodway, River Westbrook Westbrook curve log- 2013) X (Shaded) Pearson Type III curve Approximately regional 455 feet regression AE w/ 1978 Confluence with upstream of State analysis, USACE HEC-2 Floodway, Quaker Brook (redelineated Saco River Route 113 in the USGS Open- step-backwater A, X 2013) Town of East File Report (Shaded) Baldwin 75-292 Within the corporate limits of regional AE w/ Corporate limits 1980 South Portland equation USACE HEC-2 Floodway, Red Brook with the Town of (redelineated from confluence prepared by step-backwater A, X Scarborough 2013) with Jackson USGS (Shaded) Brook

87 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations Approximately AE w/ 0.83 miles USGS Maine 1980 Correlated with statistical analyses Royal River Confluence with divided flow Floodway, upstream of Regional (redelineated of USGS stream gage no. Downstream Casco Bay analysis A, X North Elm Street Equation 2013) 0106000 (Shaded) Railroad AE w/ Town of North Town of New 1980 Royal River USDA NRCS USDA NRCS Floodway, Yarmouth Gloucester (redelineated Upstream TR-20 WSP-2 A, X corporate limits corporate limits 2013) (Shaded) AE w/ 1980 Royal River Within the Town Within the Town USDA NRCS USDA NRCS Floodway, (redelineated Upstream of Gray of Gray TR-20 WSP-2 A, X 2013) (Shaded) AE w/ Town of North Town of New 1980 Royal River USDA NRCS USDA NRCS Floodway, Yarmouth Gloucester (redelineated Upstream TR-20 WSP-2 A, X corporate limits corporate limits 2013) (Shaded) AE w/ log-Pearson 1979 York-Cumberland Town of Baldwin USGS E431 Floodway, Saco River Type III (redelineated County Boundary corporate limits step-backwater A, X distribution 2013) (Shaded) log-Pearson USGS gage (no. 01066000) Type III, U.S. AE w/ Cumberland- 1978 located at Cornish, Maine, on the York-Cumberland Water USACE HEC-2 Floodway, Saco River Oxford County (redelineated Saco River, was used to establish County Boundary Resources step-backwater A, X Boundary lines 2013) the peak discharge-frequency Council (Shaded) relationships Bulletin No. 17 Confluence with log-Pearson 1979 AE w/ Saco River Left the Saco River in USGS E431 Cataract Dam Type III (redelineated Floodway, Channel the Town of step-backwater distribution 2013) X (Shaded) Standish

88 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations 1980 Within the Town Within the Town Weibull USGS E431 S.D. Warren Company for 106 Sebago Lake (redelineated AE of Windham of Windham formula step-backwater years (1872 to 1977) 2013) Within the Towns Within the Towns 1979 furnished by 40 years of record at Sebago Lake Sebago Lake of Casco and of Casco and N/A (redelineated AE USGS Dam gage Naples Naples 2013) Within the Towns Within the Towns of Frye Island, of Frye Island, 1979 Weibull S.D. Warren Company for 106 Sebago Lake Raymond, Raymond, N/A (redelineated AE formula years (1872 to 1977) Sebago, and Sebago, and 2013) Standish Standish Confluence with 1979 Confluence with the Bay of Naples USDA NRCS USDA NRCS AE w/ starting from critical depth at Songo River (redelineated Sebago Lake in the Town of TR-20 WSP-2 Floodway Sebago Lake 2013) Naples AE w/ Highland Lake 1980 USDA NRCS USDA NRCS Floodway, Stevens Brook Kansas Road Dam in the Town (redelineated TR-20 WSP-2 A, X of Bridgton 2013) (Shaded) Approximately 75 feet downstream USDA NRCS 1979 Stroudwater Confluence with USACE HEC-2 from the Town of flood hazard (redelineated AE, A River Fore River step-backwater Gorham analyses 2013) corporate limits Approximately 75 USDA NRCS feet downstream 1978 Stroudwater Confluence with discharge- AE, A, X from the Town of USACE HEC-2 (redelineated River Fore River frequency (Shaded) Gorham 2013) relationship corporate limits

89 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations Approximately 2,000 feet 1980 Confluence with USDA NRCS USDA NRCS AE, A, X Thayer Brook upstream of the (redelineated Pleasant River TR-20 WSP-2 (Shaded) confluence with 2013) Tributary A Approximately 50 Tributary 1 to Approximately 30 2005 Includes portions of LOMR 03-01- feet upstream of Presumpscot feet from Route LOMR LOMR AE 001P not superseded by LOMR Gorham-Standish (redelineated River 35 05-01-A566P Corporate Limites 2013) Approximately 50 Tributary 2 to Approximately 30 2005 Includes portions of LOMR 03-01- feet upstream of Presumpscot feet from Route LOMR LOMR AE 001P not superseded by LOMR Gorham-Standish (redelineated River 35 05-01-A566P Corporate Limites 2013) Approximately 250 feet 1980 Confluence with USDA NRCS USDA NRCS Tributary A upstream of Farm (redelineated AE Thayer Brook TR-20 WSP-2 Road in the Town 2013) of Gray Approximately USDA NRCS 3,500 feet 1978 Tributary to Confluence with discharge- Based on Stroudwater River downstream of USACE HEC-2 (redelineated AE Clark Brook Clark Brook frequency updates the confluence 2013) curve with Clark Brook Approximately 13 regional feet upstream of 1980 Confluence with equation USACE HEC-2 AE, X Trout Brook Spurwick Avenue (redelineated Fore River prepared by step-backwater (Shaded) in the Town of 2013) USGS Cape Elizabeth

90 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued

Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations Approximately Unnamed 2,850 feet Approximately 2006 Tributary to upstream of its 520 feet N/A N/A AE Colley Wright confluence with upstream of (redelineated Brook Colley Wright private drive 2013) Brook Approximately Unnamed 700 feet Approximately 2005 Tributary to upstream of its 510 feet AE, X N/A N/A Presumpscot confluence with upstream of dirt (redelineated (Shaded) River Presumpscot road 2013) River Approximately Approximately Unnamed 700 feet 2006 2,000 upstream Tributary to downstream of N/A N/A AE of Maine Central (redelineated Rich Mill Brook Maine Central Railroad 2013) Railroad Approximately Approximately Unnamed 800 feet 2006 2,900 upstream Tributary to downstream of N/A N/A AE of Maine Central (redelineated Tucker Brook Maine Central Railroad 2013) Railroad Maine Turnpike 1995 West Branch Confluence with USDA NRCS NRCS WSP-2 AE, X in the City of (redelineated Capisic Brook Capisic Brook TR-20 step-backwater (Shaded) Portland 2013) Approximately 150 feet 2006 upstream of its AE, X Westcott Brook Plummer Road N/A N/A confluence with (redelineated (Shaded) North Branch of 2013) Little River

91 Table 13: Summary of Hydrologic and Hydraulic Analyses • continued Hydrologic Study Limits Study Limits Model or Hydraulic Model Date Analyses Flood Zone Flooding Source Downstream Limit Upstream Limit Method Used or Method Used Completed on FIRM Special Considerations Approximately 1 foot upstream 1980 Confluence with USDA NRCS USDA NRCS AE, X Willet Brook from Willett Road (redelineated Stevens Brook TR-20 WSP-2 (Shaded) in the Town of 2013) Bridgton Meader Brook, East Branch Piscataqua, Falmouth, Town Falmouth, Town regression HEC-RAS 2012 A and West of of equations Branch Piscataqua Numerous Unnamed regression Tributaries or Refer to FIRM Refer to FIRM HEC-RAS 2013 A equations Local Ponding Areas

Table 14: Roughness Coefficients

Flooding Source Channel “n” Overbank “n” All Stream Channels (At 0.035 0.080 Westbrook) All Streams Studied (At Gray) 0.045 - 0.070 0.070 - 0.095 Capisic Brook (At Portland) 0.035 - 0.060 0.055 - 0.120 Corn Shop Brook (At Bridgton) 0.065 0.050 - 0.075 Crooked River (At Casco) 0.037 - 0.071 0.065 - 0.140 Crooked River (Town of 0.039 - 0.078 0.060 - 0.150 Harrison) (At Harrison) Crooked River (At Naples) 0.037 - 0.071 0.065 - 0.150 Crystal Lake Brook (At Harrison) 0.060 - 0.070 0.065 - 0.095 Ditch Brook (At Windham) 0.035 - 0.055 0.045 - 0.115 East Branch Capisic Brook (At 0.035 - 0.060 0.055 - 0.120 Portland) Fall Brook (At Portland) 0.030 - 0.055 0.030 - 0.140 Jackson Brook (At South 0.015 - 0.070 0.050 - 0.120 Portland) Long Creek (At South Portland) 0.015 - 0.070 0.050 - 0.120 Nasons Brook (At Portland) 0.025 - 0.040 0.040 - 0.080 Piscataqua River (At Falmouth) 0.040 - 0.050 0.065 - 0.080 Presumpscot River (At 0.050 0.065 - 0.120 Falmouth; At Portland) Presumpscot River (At Gorham; 0.035 - 0.060 0.045 - 0.125 At Windham) Red Brook (At South Portland) 0.015 - 0.065 0.040 - 0.100 Royal River (Upstream) ( At New 0.055 - 0.070 0.070 - 0.100 Gloucester) Royal River (Upstream) (At 0.036 - 0.056 0.060 - 0.170 North Yarmouth) Royal River (Downstream) (At 0.032 - 0.045 0.060 - 0.150 Yarmouth) Saco River (Baldwin) 0.040 - 0.045 0.080 - 0.100 Saco River (Standish) 0.030 - 0.500 0.035 - 0.120 Saco River Left Channel 0.030 - 0.500 0.035 - 0.120 (Standish) Songo River (Casco) 0.045 - 0.057 0.080 - 0.110 Songo River (Naples) 0.045 - 0.057 0.070 - 0.110

93 Table 14: Roughness Coefficients • continued Flooding Source Channel “n” Overbank “n” Stevens Brook (Bridgton) 0.022 - 0.075 0.085 - 0.100 Stroudwater River (Portland) 0.030 - 0.040 0.040 - 0.080 Trout Brook (Cape Elizabeth) 0.065 0.100 Trout Brook (South Portland) 0.015 - 0.070 0.050 - 0.100 West Branch Capisic Brook 0.035 - 0.060 0.055 - 0.120 (Portland) Willett Brook (Bridgton) 0.055 - 0.070 0.070 - 0.090

5.3 Coastal Analyses For the areas of Cumberland County that are impacted by coastal flooding processes, coastal flood hazard analyses were performed to provide estimates of coastal BFEs. Coastal BFEs reflect the increase in water levels during a flood event due to extreme tides and storm surge as well as overland wave effects.

The following subsections provide summaries of how each coastal process was considered for this FIS Report. Greater detail (including assumptions, analysis, and results) is available in the archived project documentation. Table 15 summarizes the methods and/or models used for the coastal analyses. Refer to Section 2.5.1 for descriptions of the terms used in this section.

Table 15: Summary of Coastal Analyses

Date Analysis Flooding Study Limits Study Limits Hazard Model or was Source From To Evaluated Method Used Completed Coastline from Coastline from Primary Cape Elizabeth to Cape Elizabeth to Atlantic Frontal Scarborough Scarborough PFD 4/17/2013 Ocean Dune 004, 009, 010, 004, 009, 010, (PFD) 011, 018, 021 011, 018, 021 Coastline from Coastline from ACES 2- Atlantic Wave Cape Elizabeth to Cape Elizabeth to Slope 4/17/2013 Ocean Runup Scarborough 016 Scarborough 016 Method Coastline from Coastline from Atlantic Wave ACES Cape Elizabeth to Cape Elizabeth to 4/17/2013 Ocean Runup Structure Scarborough 027 Scarborough 027 Coastline from Coastline from Cape Elizabeth to Cape Elizabeth to ACES/ Atlantic Wave Scarborough Scarborough 4/17/2013 Ocean Runup Impermeable 006, 012, 013, 006, 012, 013, Structure 014 014

94 Table 15: Summary of Coastal Analyses • continued Date Analysis Flooding Study Limits Study Limits Hazard Model or was Source From To Evaluated Method Used Completed Coastline from Coastline from Cape Elizabeth to Cape Elizabeth to Atlantic Wave Scarborough Scarborough ACES-Beach 4/17/2013 Ocean Runup 001, 002, 003, 001, 002, 003, 005, 017, 022 005, 017, 022 Coastline from Coastline from Cape Elizabeth to Cape Elizabeth to Atlantic Wave Scarborough Scarborough Runup 2.0 4/17/2013 Ocean Runup 007, 015, 019, 007, 015, 019, 025, 030, 032 025, 030, 032 Coastline from Coastline from Cape Elizabeth to Cape Elizabeth to Atlantic Scarborough Scarborough Wave TAW 4/17/2013 Ocean 008, 020, 023, 008, 020, 023, Runup 024, 026, 028, 024, 026, 028, 031 031 Coastline from Coastline from Atlantic Wave TAW/Casco Cape Elizabeth to Cape Elizabeth to 4/17/2013 Ocean Runup Bay Scarborough 029 Scarborough 029 Coastline from Coastline from South Portland to South Portland to Wave Casco Bay Harpswell 129, Harpswell 129, ACES 4/17/2013 Runup 130, 154, 155, 130, 154, 155, 158 158 Coastline from Coastline from ACES + Wave Casco Bay South Portland to South Portland to Casco Bay 4/17/2013 Runup Harpswell 036 Harpswell 036 Method Coastline from Coastline from South Portland to South Portland to Harpswell 034, Harpswell 034, Wave ACES Casco Bay 037, 049, 051, 037, 049, 051, 4/17/2013 Runup Structure 052, 057, 096, 052, 057, 096, 097, 131, 134, 097, 131, 134, 136, 143 136, 143

Coastline from Coastline from ACES South Portland to South Portland to Wave Casco Bay Structure/ 4/17/2013 Harpswell 039, Harpswell 039, Runup 128, 159 128, 159 Casco Bay

Coastline from Coastline from ACES/ South Portland to South Portland to Wave Casco Bay 4/17/2013 Harpswell 058, Harpswell 058, Runup Impermeable 060, 074, 082 060, 074, 082 Structure

95 Table 15: Summary of Coastal Analyses • continued Date Analysis Flooding Study Limits Study Limits Hazard Model or was Source From To Evaluated Method Used Completed Coastline from Coastline from South Portland to South Portland to Harpswell 040, Harpswell 040, Wave Casco Bay 055, 056, 078, 055, 056, 078, ACES-Beach 4/17/2013 Runup 081, 085, 086, 081, 085, 086, 088, 090, 094, 088, 090, 094, 137, 138, 139 137, 138, 139 Coastline from Coastline from Intact- Wave Casco Bay South Portland to South Portland to SPM/Failed- 4/17/2013 Runup Harpswell 043 Harpswell 043 ACES Coastline from Coastline from Intact- Wave Casco Bay South Portland to South Portland to SPM/Failed- 4/17/2013 Runup Harpswell 044 Harpswell 044 SPM Coastline from Coastline from Intact- Wave Casco Bay South Portland to South Portland to TAW/Failed- 4/17/2013 Runup Harpswell 046 Harpswell 046 ACES Coastline from Coastline from South Portland to South Portland to Wave Casco Bay NA 4/17/2013 Harpswell 041, Harpswell 041, Runup 042 042 Coastline from Coastline from Wave Casco Bay South Portland to South Portland to Runup 4/17/2013 Runup Harpswell 0151 Harpswell 0151 Coastline from Coastline from South Portland to South Portland to Harpswell 045, Harpswell 045, 048, 050, 054, 048, 050, 054, 070, 075, 076, 070, 075, 076, Wave Casco Bay 077, 084, 089, 077, 084, 089, Runup 2.0 4/17/2013 Runup 091, 092, 104, 091, 092, 104, 108, 109, 117, 108, 109, 117, 118, 125, 135, 118, 125, 135, 144, 147, 157, 144, 147, 157, 160 160 Coastline from Coastline from SPM + Wave Casco Bay South Portland to South Portland to Casco Bay 4/17/2013 Runup Harpswell 038 Harpswell 038 Method

96 Table 15: Summary of Coastal Analyses • continued Date Analysis Flooding Study Limits Study Limits Hazard Model or was Source From To Evaluated Method Used Completed Coastline from Coastline from South Portland to South Portland to Harpswell 033, Harpswell 033, 035, 059, 061, 035, 059, 061, 062, 063, 064, 062, 063, 064, 065, 066, 067, 065, 066, 067, 068, 069, 071, 068, 069, 071, 072, 073, 079, 072, 073, 079, 080, 083, 087, 080, 083, 087, Wave Casco Bay 093, 100, 101, 093, 100, 101, TAW 4/17/2013 Runup 102, 103, 105, 102, 103, 105, 106, 107, 110, 106, 107, 110, 111, 112, 113, 111, 112, 113, 114, 115, 116, 114, 115, 116, 119, 120, 121, 119, 120, 121, 122, 123, 124, 122, 123, 124, 126, 127, 140, 126, 127, 140, 141, 146, 152, 141, 146, 152, 156, 161 156, 161 Coastline from Coastline from South Portland to South Portland to Wave Casco Bay Harpswell 047, Harpswell 047, TAW Berm 4/17/2013 Runup 053, 095, 098, 053, 095, 098, 099 099 Coastline from Coastline from South Portland to South Portland to Wave TAW/Casco Casco Bay 4/17/2013 Harpswell 142, Harpswell 142, Runup Bay 145, 148, 149 145, 148, 149 Coastline from Coastline from Harpswell Brunswick to Brunswick to Wave Runup 2.0 4/17/2013 Sound Harpswell 132, Harpswell 132, Runup 133 133 Coastline in Coastline in Wave Quahog Bay Harpswell 150, Harpswell 150, TAW 4/17/2013 Runup 153 153 Portland Harbor Confluence with (Atlantic Maine State Pier N/A N/A 12/27/2011 Fore River Ocean and Casco Bay)

The coastal analysis in Cumberland County is divided into three groups according to the type of study performed by the STARR team. The three groups are referred to in this report as “New Transects,” “Updated Map Mod Transects,” and “Re-Evaluated Transects.” Below is a description of each group.

New Transects

Contains the 26 transects in the towns of Brunswick, Freeport, Long Island, and Yarmouth. A completely new RiskMap engineering analysis was performed for these transects (STARR 2012). This analysis includes transect numbers 68-72, and 100-120.

Updated Map Mod Transects

Contains the 36 transects in the towns of Chebaugue Island, Cumberland, and Scarborough. This study updated the former analysis (performed as part of FEMA’s previous Map Modernization Program) by updating input wave conditions from a newer wave model (Map Mod 2008). This analysis includes transect numbers 1-15 and 73-93.

Re-Evaluated Transects

Contains the 99 transects in the cities of Portland and South Portland and the towns of Cape Elizabeth, Falmouth, and Harpswell. This study updated the former analyses for the 44 community submitted transects (performed by Sebago Technics in 2009/2010 (Sebago Technics 2009a, 2009b, 2010a through 2010c)) and the remaining 55 transects within these communities (performed by STARR in 2013 under Task Order 8) to apply a consistent approach for all transects within the county. Coastal engineering performed in 2013 in these 5 communities were largely based on the additional community data submitted to FEMA in 2009. This data provided newly established initial wave conditions for 44 transects developed from STWAVE, a two-dimensional wave transformation model, but used a different approach that resulted in non- deepwater wave conditions. In 2014, a Scientific Resolution Panel (SRP) ruled that a similar approach used in the communities of Scituate and Marshfield in Plymouth County, Massachusetts was not in compliance with the guidance in the Atlantic Ocean and Gulf of Mexico Coastal Guidelines Update (FEMA, 2007a) as it did not account for depth to wavelength criteria specified to identify deepwater wave conditions. For Task Order 15, STARR updated the former analyses with deepwater wave parameters and wave runup consistent with Appendix D “Guidance for Coastal Flooding Analyses and Mapping,” (FEMA 2003a) of the Guidelines and Specifications, as well as, the “Atlantic Ocean and Gulf of Mexico Coastal Guidelines Update,” (FEMA 2007a). This analysis includes transect numbers 16-67 and 94-161.

5.3.1 Total Stillwater Elevations The total stillwater elevations (stillwater including storm surge plus wave setup) for the 1% annual chance flood were determined for areas subject to coastal flooding. The models and methods that were used to determine storm surge and wave setup are listed in Table 15. The stillwater elevation that was used for each transect in coastal analyses is shown in Table 17, “Coastal Transect Parameters.”

Figure 8: 1% Annual Chance Total Stillwater Elevations for Coastal Areas [Not Applicable to this Flood Risk Project]

Storm Surge Statistics Tidal gages can be used instead of historic records of storms when the available tidal gage record for the area represents both the astronomical tide component and the

98 storm surge component. As part of a study in Cumberland County in 2007, a review was performed between the gage record in Portland and the USACE Tidal Flood Profiles for New England (1988). The analysis indicated that the Tidal Flood Profiles could be used if updated to the 1983-2001 tidal epoch.

The 10-percent, 2-percent, 1-percent, and 0.2-percent stillwater elevations for Updated Map Mod transects should be taken from the “Technical Support Data Notebook for Coastal Engineering Analysis for Flood Insurance Study Revision” (TSDN) report for Cumberland County (OCC, Inc. 2007).

Table 16: Tide Gage Analysis Specifics [Not Applicable to this Flood Risk Project]

Combined Riverine and Tidal Effects Riverine areas that were tidally influenced, the coastal backwater was extended inland until the stillwater elevation or the coastal flooding met another flood source (i.e., a riverine flood source) with an equal water-surface elevation.

Wave Setup Analysis Wave setup was computed through the methods and models listed in Table 15. For those coastal transects where a structure was located, documentation was gathered on the structure, and the wave setup against the coastal structure was also calculated. The oscillating component of wave setup, dynamic wave setup , was calculated for areas subject to wave runup hazards.

5.3.2 Waves The energy-based significant wave height (Hmo) and peak wave period (Tp) are used as inputs to wave setup and wave runup calculations and were calculated using the Steady-State Spectral Wave Model (STWAVE). STWAVE is a phased-averaged spectral wave model that simulates depth-induced wave refraction and shoaling, depth- and steepness-induced wave breaking, diffraction, wind-wave growth, and wave-wave interaction and white capping that redistribute and dissipate energy in a growing wave field. The model accepts a spectral form of the wave as an input condition and provides Hmo and Tp results over the gridded model domain.

STARR team developed STWAVE models for the southern coastline of Cumberland County, and the results were obtained from the model for the coastal flooding analysis in the Towns of Brunswick, Chebeague Island, Cumberland, Freeport, Long Island, Scarborough, and Yarmouth.

STWAVE models were developed for the City of Portand and the towns of Cape Elizabeth, Falmouth, and Harpswell by Sebago Technics as part of their study in 2007. STARR team obtained the results from Sebago Technics models for the coastal flooding analysis in these communities (Sebago Technics 2009a, 2009b, 2010a through 2010c). This analysis was updated by STARR in 2016 to account for deepwater wave conditions and wave runup. Wave model (Coastal State University 2007) was used to calculate the nearshore wave fields required for the addition of wave setup effects. Three nested grids were used to obtain sufficient nearshore resolution to represent the radiation stress gradients required as ADCIRC inputs. Radiation stress fields output

99 from the inner grids are used by ADCIRC to estimate the contribution of breaking waves (wave setup effects) to the total Stillwater elevation.

5.3.3 Coastal Erosion A single storm episode can cause extensive erosion in coastal areas. Storm-induced erosion was evaluated to determine the modification to existing topography that is expected to be associated with flooding events. Erosion was evaluated using the methods listed in Table 15. The Coastal Hazard Analysis Modeling Program CHAMP is a Microsoft (MS) Windows-interfaced Visual Basic language program that allows the user to enter data, perform coastal engineering analyses, view and tabulate results, and chart summary information for each representative transect along a coastline within a user-friendly graphical interface. With CHAMP, the user can import digital elevation data; perform storm-induced erosion treatments, wave height, and wave runup analyses; plot summary graphics of the results; and create summary tables and reports in a single environment. CHAMP version 2.0 (FEMA 2007b) was used to perform erosion analysis, run WHAFIS, and apply RUNUP 2.0 to transects without coastal structures. Application of CHAMP followed the instructions in the FEMA Guidelines and Specifications (FEMA 2007a) and the Coastal Hazard Analysis Modeling Program user’s guide found in the software documentation (FEMA 2007c).The post-event eroded profile was used for the subsequent transect-based onshore wave hazard analyses.

5.3.4 Wave Hazard Analyses Overland wave hazards were evaluated to determine the combined effects of ground elevation, vegetation, and physical features on overland wave propagation and wave runup. These analyses were performed at representative transects along all shorelines for which waves were expected to be present during the floods of the selected recurrence intervals. The results of these analyses were used to determine elevations for the 1% annual chance flood.

Transect locations were chosen with consideration given to the physical land characteristics as well as development type and density so that they would closely represent conditions in their locality. Additional consideration was given to changes in the total stillwater elevation. Transects were spaced close together in areas of complex topography and dense development or where total stillwater elevations varied. In areas having more uniform characteristics, transects were spaced at larger intervals. Transects shown in Figure 9, “Transect Location Map,” are also depicted on the FIRM. Table 17 provides the location, stillwater elevations, and starting wave conditions for each transect evaluated for overland wave hazards. In this table, “starting” indicates the parameter value at the beginning of the transect.

Wave Height Analysis Wave height analyses were performed to determine wave heights and corresponding wave crest elevations for the areas inundated by coastal flooding and subject to overland wave propagation hazards. Refer to Figure 6 for a schematic of a coastal transect evaluated for overland wave propagation hazards.

Wave heights and wave crest elevations were modeled using the methods and models listed in Table 15, “Summary of Coastal Analyses”.

100

Wave Runup Analysis Wave runup analyses were performed to determine the height and extent of runup beyond the limit of stillwater inundation for the 1% annual chance flood. Wave runup elevations were modeled using the methods and models listed in Table 15.

101

Table 17: Coastal Transect Parameters

Starting Wave Conditions for Starting Stillwater Elevations (ft NAVD88) the 1% Annual Chance Significant Peak Wave Coastal Wave Height Period 10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flood Source Transect Hs (ft) Tp (sec) Chance Chance Chance Chance Chance Atlantic Ocean 001 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 002 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 003 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 004 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 005 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 006 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 007 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 008 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 009 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 010 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 011 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 012 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 013 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 014 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 015 29.9 11.4 7.9 * 8.5 8.8 9.5 Atlantic Ocean 016 8.8 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 017 21.2 12.2 7.9 * 8.5 8.8 9.5

*Not calculated for this Flood Risk Project

102 Table 17: Coastal Transect Parameters • continued

Starting Wave Conditions for Starting Stillwater Elevations (ft NAVD88) the 1% Annual Chance Significant Peak Wave Coastal Wave Height Period 10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flood Source Transect Hs (ft) Tp (sec) Chance Chance Chance Chance Chance Atlantic Ocean 018 20.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 019 23.3 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 020 12.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 021 19.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 022 15.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 023 23.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 024 23.5 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 025 24.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 026 21.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 027 22.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 028 21.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 029 21.0 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 030 21.5 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 031 22.3 12.2 7.9 * 8.5 8.8 9.5 Atlantic Ocean 032 24.0 12.2 7.9 * 8.5 8.8 9.5 Casco Bay 033 22.0 12.2 7.9 * 8.5 8.8 9.5 Casco Bay 034 15.0 12.2 7.9 * 8.5 8.8 9.5 Casco Bay 035 10.2 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 036 4.7 12.5 8.0 * 8.6 8.9 9.5

*Not calculated for this Flood Risk Project

103 Table 17: Coastal Transect Parameters • continued

Starting Wave Conditions for Starting Stillwater Elevations (ft NAVD88) the 1% Annual Chance Significant Peak Wave Coastal Wave Height Period 10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flood Source Transect Hs (ft) Tp (sec) Chance Chance Chance Chance Chance Casco Bay 037 4.5 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 038 3.3 11.1 8.0 * 8.6 8.9 9.5 Casco Bay 039 2.8 11.1 8.0 * 8.6 8.9 9.5 Casco Bay 040 3.3 4.4 8.0 * 8.6 8.9 9.5 Casco Bay 041 3.7 4.5 8.0 * 8.6 8.9 9.5 Casco Bay 042 3.7 4.5 8.0 * 8.6 8.9 9.5 Casco Bay 043 4.3 5.3 8.0 * 8.6 8.9 9.5 Casco Bay 044 3.4 4.2 8.0 * 8.6 8.9 9.5 Casco Bay 045 2.7 3.0 8.0 * 8.6 8.9 9.5 Casco Bay 046 2.6 3.0 8.0 * 8.6 8.9 9.5 Casco Bay 047 2.5 4.2 8.0 * 8.6 8.9 9.5 Casco Bay 048 6.0 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 049 3.5 3.8 8.0 * 8.6 8.9 9.5 Casco Bay 050 1.7 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 051 13.8 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 052 16.4 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 053 5.7 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 054 16.9 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 055 18.7 12.5 8.0 * 8.6 8.9 9.5

*Not calculated for this Flood Risk Project

104 Table 17: Coastal Transect Parameters • continued

Starting Wave Conditions for Starting Stillwater Elevations (ft NAVD88) the 1% Annual Chance Significant Peak Wave Coastal Wave Height Period 10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flood Source Transect Hs (ft) Tp (sec) Chance Chance Chance Chance Chance Casco Bay 056 14.2 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 057 10.0 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 058 2.6 3.3 7.9 * 8.5 8.8 9.5 Casco Bay 059 2.6 4.2 7.9 * 8.5 8.8 9.5 Casco Bay 060 2.7 4.2 7.9 * 8.5 8.8 9.5 Casco Bay 061 3.4 4.0 7.9 * 8.5 8.8 9.5 Casco Bay 062 3.1 3.7 7.9 * 8.5 8.8 9.5 Casco Bay 063 3.3 3.7 7.9 * 8.5 8.8 9.5 Casco Bay 064 3.1 4.8 8.0 * 8.6 8.9 9.5 Casco Bay 065 3.0 3.6 8.0 * 8.6 8.9 9.5 Casco Bay 066 2.9 3.7 8.0. * 8.6 8.9 9.5 Casco Bay 067 2.8 3.7 8.0 * 8.6 8.9 9.5 Casco Bay 068 13.1 9.2 8.0 * 8.6 8.9 9.5 Casco Bay 069 18.0 10.2 8.0 * 8.6 8.9 9.5 Casco Bay 070 18.0 10.2 8.0 * 8.6 8.9 9.5 Casco Bay 071 8.5 9.5 8.0 * 8.6 8.9 9.5 Casco Bay 072 2.6 7.7 8.0 * 8.6 8.9 9.5 Casco Bay 073 3.3 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 074 2.0 7.7 8.1 * 8.7 9.1 9.7

*Not calculated for this Flood Risk Project

105 Table 17: Coastal Transect Parameters • continued

Starting Wave Conditions for Starting Stillwater Elevations (ft NAVD88) the 1% Annual Chance Significant Peak Wave Coastal Wave Height Period 10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flood Source Transect Hs (ft) Tp (sec) Chance Chance Chance Chance Chance Casco Bay 075 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 076 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 077 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 078 3.3 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 079 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 080 4.6 7.4 8.1 * 8.7 9.1 9.7 Casco Bay 081 4.3 7.8 8.1 * 8.7 9.1 9.7 Casco Bay 082 4.3 7.8 8.1 * 8.7 9.1 9.7 Casco Bay 083 8.5 9.5 8.1 * 8.7 9.1 9.7 Casco Bay 084 6.2 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 085 6.2 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 086 6.2 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 087 6.2 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 088 6.2 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 089 6.2 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 090 6.2 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 091 8.5 9.5 8.1 * 8.7 9.1 9.7 Casco Bay 092 6.2 8.1 8.1 * 8.7 9.1 9.7 Casco Bay 093 29.9 11.4 8.1 * 8.7 9.1 9.7

*Not calculated for this Flood Risk Project

106 Table 17: Coastal Transect Parameters • continued

Starting Wave Conditions for Starting Stillwater Elevations (ft NAVD88) the 1% Annual Chance Significant Peak Wave Coastal Wave Height Period 10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flood Source Transect Hs (ft) Tp (sec) Chance Chance Chance Chance Chance Casco Bay 094 2.5 3.4 8.0 * 8.6 8.9 9.5 Casco Bay 095 9.5 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 096 9.6 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 097 4.3 11.1 8.0 * 8.6 8.9 9.5 Casco Bay 098 12.0 11.1 8.0 * 8.6 8.9 9.5 Casco Bay 099 7.2 12.5 8.0 * 8.6 8.9 9.5 Casco Bay 100 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 101 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 102 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 103 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 104 2.0 7.7 8.1 * 8.7 9.1 9.7 Casco Bay 105 3.9 6.8 8.1 * 8.7 9.1 9.7 Casco Bay 106 3.9 6.8 8.1 * 8.7 9.1 9.7 Casco Bay 107 4.6 7.4 8.1 * 8.7 9.1 9.7 Casco Bay 108 3.0 5.1 8.1 * 8.7 9.1 9.7 Casco Bay 109 3.0 5.1 8.1 * 8.7 9.1 9.7 Casco Bay 110 3.0 5.1 8.1 * 8.7 9.1 9.7 Casco Bay 111 3.0 5.1 8.1 * 8.7 9.1 9.7 Casco Bay 112 3.0 5.1 8.1 * 8.7 9.1 9.7

*Not calculated for this Flood Risk Project

107 Table 17: Coastal Transect Parameters • continued

Starting Wave Conditions for Starting Stillwater Elevations (ft NAVD88) the 1% Annual Chance Significant Peak Wave Coastal Wave Height Period 10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flood Source Transect Hs (ft) Tp (sec) Chance Chance Chance Chance Chance Casco Bay 113 4.6 7.4 8.1 * 8.7 9.1 9.7 Casco Bay 114 4.6 7.4 8.1 * 8.7 9.1 9.7 Casco Bay 115 4.6 7.4 8.1 * 8.7 9.1 9.7 Casco Bay 116 3.3 3.9 8.1 * 8.7 9.1 9.7 Casco Bay 117 3.3 3.9 8.1 * 8.7 9.1 9.7 Casco Bay 118 3.3 3.9 8.1 * 8.7 9.1 9.7 Casco Bay 119 3.3 3.9 8.1 * 8.7 9.1 9.7 Casco Bay 120 2.0 5.3 8.1 * 8.7 9.1 9.7 Casco Bay 121 3.8 5.9 8.1 * 8.7 9.1 9.7 Casco Bay 122 2.5 4.5 8.1 * 8.7 9.1 9.7 Casco Bay 123 2.1 5.0 8.1 * 8.7 9.1 9.7 Casco Bay 124 2.5 4.8 8.1 * 8.7 9.1 9.7 Casco Bay 125 2.2 3.3 8.1 * 8.7 9.1 9.7 Casco Bay 126 2.8 5.9 8.1 * 8.7 9.1 9.7 Casco Bay 127 3.2 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 128 3.0 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 129 13.9 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 130 6.1 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 131 7.0 12.5 8.1 * 8.7 9.1 9.7

*Not calculated for this Flood Risk Project

108 Table 17: Coastal Transect Parameters • continued

Starting Wave Conditions for Starting Stillwater Elevations (ft NAVD88) the 1% Annual Chance Significant Peak Wave Coastal Wave Height Period 10% Annual 4% Annual 2% Annual 1% Annual 0.2% Annual Flood Source Transect Hs (ft) Tp (sec) Chance Chance Chance Chance Chance Harpswell Sound 132 1.3 2.9 8.1 * 8.7 9.1 9.7 Harpswell Sound 133 2.3 3.2 8.1 * 8.7 9.1 9.7 Harpswell Sound 134 2.0 3.5 8.1 * 8.7 9.1 9.7 Harpswell Sound 135 2.3 4.3 8.1 * 8.7 9.1 9.7 Casco Bay 136 2.5 6.3 8.1 * 8.7 9.1 9.7 Casco Bay 137 4.0 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 138 8.0 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 139 1.0 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 140 19.3 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 141 13.3 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 142 11.7 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 143 9.4 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 144 3.0 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 145 8.5 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 146 1.0 4.5 8.1 * 8.7 9.1 9.7 Casco Bay 147 7.0 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 148 7.2 12.5 8.1 * 8.7 9.1 9.7 Casco Bay 149 5.0 12.5 8.1 * 8.7 9.1 9.7 Quahog Bay 150 2.9 12.5 8.1 * 8.7 9.1 9.7

*Not calculated for this Flood Risk Project

109 Table 17: Coastal Transect Parameters • continued

*Not calculated for this Flood Risk Project

110 Figure 9: Transect Location Map

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5 0 « «¬ ¬ «¬04 9 8 0 ¦95 47 9 ¬« ¨§ 4 0 6 4 CITY OF 3 «¬ 0 CITY OF 0 4 ¬« «¬ 0«¬ 057 PORTLAND «¬ PORTLAND 0 56 «¬42 0¬ 9 « 3 0 «¬0 ¬« 050 5 TOWN 041 8 «¬ 4 «¬055 «¬ 3 OF LONG 0 ¬« ISLAND 052 0 ¬« £1A «¬37 3 1 0«¬5 6 0 3 4 0 0 ¬«0 0 ¬« 3 5 ¬« «¬5 295 1 ¨§¦ 3 3 4 0 CITY OF 3 ¬« 0¬« SOUTH ¬0«32 PORTLAND «¬031 «¬030 TOWN

OF CAPE 8 7 2 2 £1 0¬« 0¬« 1 ELIZABETH 9 0¬«2

0 TOWN OF ¬«2 6 SCARBOROUGH «¬0 1 0 «¬ 5 5 1 02 Atlantic Ocean 4 ¬«

4 0 6 2 0 ¬« 01 2 0 «¬ 0 ¬«1 «¬02 ¬« 3 7 0 «¬02 «¬0 1 4 1 0 0 0 2 ¬« «¬ «¬1 «¬0 2 1 2 3

«¬0 1 0 «¬0 2 3 8 0 0

0 1 1 ¬ « 0 ¬« 5 0 0 0 ¬« ¬«1 «¬01 0 0 9 ¬«09 8 0¬«0 «¬0 6 0

0 7

0 ¬« F FIGURE 9

I APPROXIMATE SCALE G FEDERAL EMERGENCY MANAGEMENT AGENCY 0 5 10 U Miles R

E CUMBERLAND COUNTY, ME

2 (ALL JURISDICTIONS) TRANSECT LOCATION MAP

5.4 Alluvial Fan Analyses This section is not applicable to this Flood Risk Project.

Table 18: Summary of Alluvial Fan Analyses [Not Applicable to this Flood Risk Project]

Table 19: Results of Alluvial Fan Analyses [Not Applicable to this Flood Risk Project]

112