Volume 1 (PDF)

Federal Emergency Management Agency 
FLOOD INSURANCE STUDY NUMBER 
09011CV001B 
  
BOZRAH, TOWN OF 
COLCHESTER, TOWN OF 
EAST LYME, TOWN OF 
FRANKLIN, TOWN OF 
GRISWOLD, TOWN OF 
GROTON LONG POINT ASSOCIATION 
GROTON, CITY OF 
GROTON, TOWN OF 
JEWETT CITY, BOROUGH OF 
LEBANON, TOWN OF 
LEDYARD, TOWN OF 
LISBON, TOWN OF 
LYME, TOWN OF 
MONTVILLE, TOWN OF 
NEW LONDON, CITY OF 
NOANK FIRE DISTRICT 
NORTH STONINGTON, TOWN OF 
NORWICH, CITY OF 
OLD LYME, TOWN OF 
PRESTON, TOWN OF 
SALEM, TOWN OF 
SPRAGUE, TOWN OF 
STONINGTON, BOROUGH OF 
STONINGTON, TOWN OF 
VOLUNTOWN, TOWN OF 
WATERFORD, TOWN OF 
090094 
090095 
090096 
090154 
090173 
090167 
090126 
090097 
090098 
090155 
090157 
090172 
090127 
090099 
090100 
090129 
090101 
090102 
090103 
090139 
090156 
090105 
090193 
090106 
090143 
090107 
 
Volume 1 of 4 
Revised: 
August 5, 2013 
New London County 

 
 
 
 
 
NOTICE TO 
 
FLOOD INSURANCE STUDY USERS 
 
 
Communities participating in the National Flood Insurance Program have established repositories of flood 
hazard data for floodplain management and flood insurance purposes.  This Flood Insurance Study (FIS) 
report may not contain all data available within the repository.  It is advisable to contact the community 
repository for any additional data. 
 
Part or all of this FIS may be revised and republished at any time.  In addition, part of this FIS report may be 
revised by the Letter of Map Revision process, which does not involve republication or redistribution of the 
FIS report.  It is, therefore, the responsibility of the user to consult with community officials and to check 
the community repository to obtain the most current FIS report components. 
 
 
Initial Countywide FIS Effective Date:  July 18, 2011 
 
Revised Countywide FIS Date:  August 5, 2013 
 

i 
 
 
TABLE OF CONTENTS – Volume 1 – August 5, 2013 
 
Page 
 
1.0 
INTRODUCTION 
1 
1.1 
Purpose of Study 
1 
1.2 
Authority and Acknowledgments 
1 
1.3 
Coordination 
7 
 
2.0 
AREA STUDIED 
 9 
2.1 
Scope of Study 
9 
2.2 
Community Description 
19 
2.3 
Principal Flood Problems 
20 
2.4 
Flood Protection Measures 
26 
 
3.0 
ENGINEERING METHODS 
  28 
3.1 
Riverine Hydrologic Analyses 
28 
3.2 
Riverine Hydraulic Analyses 
47 
3.3 
Coastal Hydrologic Analyses 
54 
3.4 
Coastal Hydraulic Analyses 
56 
3.5 
Vertical Datum 
76 
 
4.0 
FLOODPLAIN MANAGEMENT APPLICATIONS 
78 
4.1 
Floodplain Boundaries 
78 
4.2 
Floodways 
80 
 
 
 
FIGURES 
 
Figure 1 – Transect Schematic 
59 
 
Figure 2 – Transect Location Map 
70 
 
Figure 3 – Floodway Schematic 
82 
 
 
 
 
 
 
 

ii 
 
TABLE OF CONTENTS – Volume 1 – continued 
    Page 
 
 
TABLES 
 
Table 1 – CCO Meeting Dates for Precountywide FIS 
7-8 
 
Table 2 – Flooding Sources Studied by Detailed Methods 
9-14 
 
Table 3 – Flooding Sources Studied by Approximate Methods 
15-18 
 
Table 4 – Letters of Map Change 
19 
 
Table 5 – Summary of Discharges 
35-46 
 
Table 6 – Summary of Pond Stillwater Elevations 
46-47 
 
Table 7 – Manning's "n" Values 
52-54 
 
Table 8 – Summary of Coastal Stillwater Elevations 
55 
 
Table 9 – Transect Descriptions 
60-69 
 
Table 10 – Transect Data 
71-76 
 
 
TABLE OF CONTENTS – Volume 2 – August 5, 2013 
 
Page 
 
5.0 
INSURANCE APPLICATIONS 
143 
 
6.0 
FLOOD INSURANCE RATE MAP 
144 
 
7.0 
OTHER STUDIES 
149 
 
8.0 
LOCATION OF DATA 
149 
 
9.0 
BIBLIOGRAPHY AND REFERENCES 
149 
 
 
 TABLES 
Table 11 – Floodway Data 
83-142 
 
Table 12 – Community Map History 
145-148 
 

iii 
 
TABLE OF CONTENTS – Volume 3 – August 5, 2013 
 
 
EXHIBITS 
 
Exhibit 1 - Flood Profiles 
 
Anguilla Brook  
 
 
 
 
 
Panels 1P-4P 
Beaver Brook (Town of Lyme)  
 
 
 
Panels 5P-6P 
Beaver Brook (Town of Sprague) 
  
 
 
Panels 7P-8P 
Birch Plain Creek  
 
 
 
 
 
Panels 9P-12P 
Blissville Brook  
 
 
 
 
 
Panels 13P-15P 
Bobbin Mill Brook   
 
 
 
 
Panel 16P 
Copps Brook  
 
 
 
 
 
Panels 17P-18P 
Day Meadow Brook   
 
 
 
 
Panel 19P 
Denison Brook  
 
 
 
 
 
Panels 20P-21P 
East Branch Eight Mile River  
 
 
 
Panels 22P-24P 
Eccleston Brook  
 
 
 
 
 
Panels 25P-26P 
Eight Mile River  
 
 
 
 
 
Panels 27P-29P 
Fishtown Brook  
 
 
 
 
 
Panels 30P-31P 
Flat Brook   
 
 
 
 
 
Panels 32P-33P 
Ford Brook   
 
 
 
 
 
Panels 34P-36P 
Fort Hill Brook  
 
 
 
 
 
Panels 37P-42P 
Fourmile River  
 
 
 
 
 
Panels 43P-46P 
Gardner Brook  
 
 
 
 
 
Panels 47P-49P 
Goldmine Brook  
 
 
 
 
 
Panel 50P 
Great Meadow Brook  
 
 
 
 
Panels 51P-53P 
Great Plain Brook  
 
 
 
 
 
Panel 54P 
Green Fall River  
 
 
 
 
 
Panels 55P-57P 
Harris Brook  
 
 
 
 
 
Panels 58P-61P 
Hunter Brook  
 
 
 
 
 
Panel 62P 
Jeremy River  
 
 
 
 
 
Panel 63P 
Joe Clark Brook  
 
 
 
 
 
Panels 64P-65P 
Jordan Brook  
 
 
 
 
 
Panels 66P-70P 
Judd Brook   
 
 
 
 
 
Panels 71P-74P 
Latimer Brook  
 
 
 
 
 
Panels 75P-82P 
Little River   
 
 
 
 
 
Panels 83P-84P 
Meadow Brook  
 
 
 
 
 
Panels 85P-88P 
Nevins Brook  
 
 
 
 
 
Panels 89P-90P 
Norwichtown Brook  
 
 
 
 
Panel 91P 
Oxoboxo Brook  
 
 
 
 
 
Panels 92P-95P 
 
 
 
 
 
 
 
 
 
 
 

iv 
 
TABLE OF CONTENTS – Volume 4 – August 5, 2013 
 
 
EXHIBITS – continued 
 
Exhibit 1 - Flood Profiles - continued 
 
Pachaug River  
 
 
 
 
 
Panels 96P-101P 
Pachaug River (Town of Voluntown)                                        Panels 102P-104P 
Pattagansett River   
 
 
 
 
Panels 105P-109P 
Pawcatuck River  
 
 
 
 
 
Panels 110P-111P 
Pine Swamp Brook   
 
 
 
 
Panel 112P 
Quinebaug River  
 
 
 
 
 
Panels 113P-116P 
Shewville Brook  
 
 
 
 
 
Panel 117P 
Shunock River  
 
 
 
 
 
Panels 118P-123P 
Spaulding Pond Brook  
 
 
 
 
Panels 124P-126P 
Susquetonscut Brook (Town of Franklin) 
 
 
Panels 127P-129P 
Susquetonscut Brook (Town of Lebanon)  
 
 
Panels 130P-132P 
Tenmile River  
 
 
 
 
 
Panels 133P-135P 
Thames River and Shetucket River   
 
 
Panel 136P 
Shetucket River  
 
 
 
 
 
Panels 137P-140P 
Trading Cove Brook  
 
 
 
 
Panels 141P-142P 
Tributary A   
 
 
 
 
 
Panels 143P-145P 
Tributary B   
 
 
 
 
 
Panel 146P 
Tributary C   
 
 
 
 
 
Panel 147P 
Tributary D   
 
 
 
 
 
Panel 148P 
Tributary F   
 
 
 
 
 
Panel 149P 
Whitford Brook (Town of Groton)  
 
 
 
Panels 150P-151P 
Whitford Brook (Town of Ledyard)   
 
 
Panel 152P 
Williams Brook  
 
 
 
 
 
Panels 153P-154P 
Yantic River  
 
 
 
 
 
Panels 155P-161P 
Yantic River East Channel                                             
Panel 162P 
 
 
 
 
 
Exhibit 2 - 
Flood Insurance Rate Map Index 
 
Flood Insurance Rate Map 

 
1 
 
 
FLOOD INSURANCE STUDY 
NEW LONDON COUNTY, CONNECTICUT (ALL JURISDICTIONS) 
 
1.0 
INTRODUCTION 
 
1.1 
Purpose of Study 
 
This Flood Insurance Study (FIS) revises and supersedes the FIS reports and/or Flood 
Insurance Rate Maps (FIRMs) in the geographic area of New London County, including 
the Cities of Groton, New London and Norwich, the Towns of Bozrah, Colchester, East 
Lyme, Franklin, Griswold, Groton, Lebanon, Ledyard, Lisbon, Lyme, Montville, North 
Stonington, Old Lyme, Preston, Salem, Sprague, Stonington, Voluntown, and Waterford, 
the political subdivisions of Noank Fire District, and Groton Long Point Association, and 
the Boroughs of Jewett City and Stonington  (referred to collectively herein as New 
London County), and aids in the administration of the National Flood Insurance Act of 
1968 and the Flood Disaster Protection Act of 1973.  The Pequot Indian Reservation is 
also labeled on the FIRMs. This study has developed flood-risk data for various areas of 
the county that will be used to establish actuarial flood insurance rates. This information 
will also be used by the communities of New London County to update existing 
floodplain regulations as part of the Regular Phase of the National Flood Insurance 
Program (NFIP), and by local and regional planners to further promote sound land use 
and floodplain development. Minimum floodplain management requirements for 
participation in NFIP are set forth in the Code of Federal Regulations at 44 CFR, 60.3. 
 
In some States or communities, floodplain management criteria or regulations may exist 
that are more restrictive or comprehensive than the minimum Federal requirements.  In 
such cases, the more restrictive criteria take precedence, and the State (or other 
jurisdictional agency) will be able to explain them. 
 
1.2 
Authority and Acknowledgments 
 
The sources of authority for this FIS report are the National Flood Insurance Act of 1968 
and the Flood Disaster Protection Act of 1973. 
 
The July 18, 2011 Countywide FIS was prepared to incorporate all the communities 
within New London County in a countywide format.  Information on the authority and 
acknowledgements for each jurisdiction included in this countywide FIS, as compiled 
from their previously printed FIS reports and FIS Supplement-Wave Height Analysis 
Reports, is shown below: 

 
2 
Bozrah, Town of: 
In the original March 30, 1981 study, the 
hydrologic and hydraulic analyses were 
prepared by the U.S. Army Corps of Engineers 
(USACE) 
for 
the 
Federal 
Insurance 
Administration (FIA), under Inter-Agency 
Agreement No. IAA-H-9-79. That work was 
completed in March 1980. 
 
In the 1995 revision, the hydrologic and 
hydraulic analyses for the Yantic River were 
prepared by Roald Haestad, Inc., for the 
Federal Emergency Management Agency 
(FEMA), under Contract No. EMW-90-C-
3126. This work was completed in December 
1992. Additional hydrologic and hydraulic 
analyses were prepared by Roald Haestad,
Inc., during the preparation of the FIS for the 
City of Norwich. That work was completed in 
March 1992. 
 
Colchester, Town of: 
In the original December 15, 1981 study and 
June 15, 1982 FIRM, the hydrologic and 
hydraulic analyses were prepared by the U.S. 
Geological Survey (USGS) for the FIA, under 
Inter-Agency Agreement No. IAA-H-14-78. 
That work was completed in March 1980. 
 
In the July 15, 1992 revised study, hydrologic 
and hydraulic analyses for Meadow Brook and 
Day Meadow Brook were prepared by the 
USGS 
for 
the 
Federal 
Emergency 
Management Agency (FEMA) under Inter-
Agency Agreement No. EMW-87-E-2764,
Project Order No. 1. This study was completed 
in December 1990. 
 
For the June 4, 1996 revision, the hydrologic 
and hydraulic analyses for Judd Brook were 
taken from the precountywide FIS for the 
Borough of Colchester. 
 
East Lyme, Town of: 
For the December 15, 1980 study, the 
hydrologic and hydraulic analyses were 
prepared by James P. Purcell Associates, Inc., 
for the FIA, under Contract No. H-4561. That 
work was completed in March 1979. 
 
The wave height analysis, dated December 15, 
1983, was prepared by Dewberry & Davis for 

 
3 
East Lyme, Town of: - continued 
the FEMA, under Contract No. EMW-C-0543. 
That work was completed in January 1982. 
 
For the June 16, 1992 revision, the hydrologic 
and hydraulic analyses were prepared by 
Green International Affiliates, Inc., for FEMA, 
under Contract No. EMW-93-C-4144 This 
work was completed in January 1994. 
 
Franklin, Town of 
The hydrologic and hydraulic analyses for the 
1981 study were prepared by the USACE, 
New England Division for the FIA, under 
Inter-Agency Agreement NO. IAA-H-9-79. 
This work was completed in May 1980. 
 
Griswold, Town of: 
The hydrologic and hydraulic analyses for the 
1983 study were completed by Dewberry & 
Davis, a technical evaluation contractor, for 
FEMA, under Contract No. EMW-C-0543. 
This work was completed in May 1983. 
 
Groton, City of: 
The wave height analysis for this study was 
prepared by Dewberry & Davis for FEMA, 
under Contract No. EMW-C-0543. This work 
was completed in March 1983.  
 
Groton Long Point Association: 
The wave height analysis for this study was 
prepared by Dewberry & Davis for FEMA. 
This work was completed in March 1982. 
 
Groton, Town of: 
The hydrologic and hydraulic analyses in the 
February 15, 1984 study represent a revision 
of the original analyses by the USACE for 
FEMA, under Inter-Agency Agreement No. 
lAA-H-2-73, project Order 1, and lAA-H-19-
74, project Order 22.  The updated riverine 
analysis was prepared by James P. Purcell 
Associates, Inc., under agreement with FEMA. 
The updated riverine analysis was completed 
in March 1979. The wave height analysis for 
this study was prepared by Dewberry & Davis 
for FEMA, under Contract No. EMW-C0543. 
This work was completed in March 1983. 
 
Jewett City, Borough of: 
The hydrologic and hydraulic analyses for the 
1984 study were prepared by Dewberry & 
Davis, taken from the FIS for the Town of 
Griswold, Connecticut, for FEMA under  
 

 
4 
Jewett City, Borough of: - continued 
Contract No. EMW-C-0968. This work was 
completed in May 1983. 
 
Lebanon, Town of: 
The hydrologic and hydraulic analyses for the 
1988 study were prepared by the USGS for 
FEMA, under Inter-Agency Agreement No. 
EMW-85-E-1823, Project Order No. 20. This 
work was completed in December 1986. 
 
Ledyard, Town of: 
The hydrologic and hydraulic analyses for the 
1980 study were prepared by Luchs and 
Beckerman for the FIA, under Contract No. H-
4725. This study was completed in April 1979.
 
Lisbon, Town of: 
The hydrologic and hydraulic analyses for the 
1984 study were completed by Dewberry & 
Davis, a technical evaluation contractor, for 
FEMA, under Contract No. EMW-C-0543. 
This work was completed in April 1983. 
 
Lyme, Town of: 
The hydrologic and hydraulic analyses for the 
1978 study were performed by the Soil 
Conservation Service (SCS NRSC), Storrs, 
Connecticut, for the FIA, under Inter-Agency 
Agreement No. IAA-H-9-76, Project Order 
No. 1. This work, which was completed in 
November 1976, covered all flooding sources 
affecting the Town of Lyme, with the 
exception of Uncas Pond and Norwich Pond, 
which were determined to be Zone A in 
December 1976, by Dames and Foore, under 
Contract to FIA. 
 
Montville, Town of: 
In the original January 1980 study, the 
hydrologic and hydraulic analyses were 
prepared by James P. Purcell Associates, Inc., 
for the FIA, under Contract No. H-4561. That 
work was completed in March 1979. 
 
In the December 5, 1995 revision, the 
hydrologic and hydraulic analyses for Latimer 
Brook were prepared by Green International 
Affiliates, Inc., for FEMA, under Contract No. 
EMW-93-C-4144. This work was completed 
in February 1994. The hydrologic and 
hydraulic analyses for Trading Cove Brook 
were obtained from the March 1994 study for 
the City of Norwich. 
 

 
5 
New London, City of  
The wave height analysis for this study was 
prepared by Dewberry & Davis for FEMA, 
under Contract No. EMW-C-0543. This work 
was completed in March 1983. 
 
Noank Fire District  
The wave height analysis for this study was 
prepared by Dewberry & Davis for FEMA, 
under Contract No. EMW-C-0543. This work 
was completed in December 1982.  
 
North Stonington, Town of: 
The hydrologic and hydraulic analyses for the 
1984 study were completed by Dewberry & 
Davis, a technical evaluation contractor, for 
FEMA under Contract No. EMW-H-4833. 
This work was completed in August 1983. 
 
Norwich, City of: 
The hydrologic and hydraulic analyses for the 
June 15, 1978 study were prepared by 
Anderson-Nichols and Company, Inc., for 
FEMA, under Contract No. H-3862.   
 
In the November 1, 1985 revision, the updated 
analyses for the Thames and Yantic Rivers 
were prepared by Dewberry & Davis under 
agreement with FEMA. That revised study 
was completed in July 1984. In the April 15, 
1992 revision updated information for the 
Shetucket River was prepared by the USGS 
for FEMA under Inter-Agency Agreement No. 
EMM-86-E-2224, Project Order No. 1. That 
work was completed in December 1989. In the 
1994 revision, the hydrologic and hydraulic 
analyses for the streams studied by detailed 
methods were prepared by Roald Haestad, 
Inc., 
for 
FEMA, 
under 
Inter-Agency 
Agreement No. EMW-90-C-3126. That work 
was completed in March 1992. 
 
Old Lyme, Town of  
The wave height analysis for this study was 
prepared by Dewberry & Davis for FEMA, 
under Contract No. EMW-C-0543. This work 
was completed in February 1983.  
 
Preston, Town of: 
The hydrologic and hydraulic analyses for the 
1984 study were completed by Dewberry & 
Davis, a technical evaluation contractor, for 
FEMA, under Contract No. EMW-C-0543. 
This work was completed in April 1983. 
 

 
6 
Salem, Town of: 
The hydrologic and hydraulic analyses for the 
1981 study were prepared by the USACE for 
FEMA, under Inter-Agency Agreement No. 
IAA-H-9-79. This work was completed in 
January 1980. 
 
Sprague, Town of: 
The hydrologic and hydraulic analyses for the 
1984 study were completed by Dewberry & 
Davis, a technical evaluation contractor, for 
FEMA, under Contract No. EMW-C-0543. 
This work was completed in July 1983. 
 
Stonington, Borough of  
The wave height analysis for this study was 
prepared by Dewberry & Davis for FEMA, 
under Contract NO. W-C-0543. This work 
was completed in November 1982.  
 
Stonington, Town of  
The wave height analysis for this study was 
prepared by Dewberry & Davis for FEMA, 
under Contract No. EMW-C-0543. This work 
was completed in January 1983. 
 
Voluntown, Town of: 
The hydrologic and hydraulic analyses for the 
1984 study were prepared by the USGS for the 
FEMA, under Inter-Agency Agreement No. 
EMU-85-E-1823, Project Order No. 20. This 
work was completed in September 1985. 
 
Waterford, Town of: 
The hydrologic and hydraulic analyses for the 
February 4, 1981 study were prepared by 
James P. Purcell Associates, Inc., for FEMA, 
under Contract No. H-4561. The work for the 
original study was completed in March 1979. 
 
The hydrologic and hydraulic analyses, 
including wave height analysis, in the 
September 5, 1990 revision were prepared by 
the USACE, New England Division, for 
FEMA, under Inter-Agency Agreement No. 
EMW-E-0941, 
Project 
Order 
No. 
1, 
Amendment No. 26. The work for this 
revision was completed in August 1987. 
 
For the July 18, 2011 countywide FIS, redelineation of coastal flood hazard data was 
performed for open water flooding sources in the Town of East Lyme, City of Groton, 
Groton Long Point Association, Town of Groton, Noank Fire District, Town of Old 
Lyme, City of New London, Borough of Stonington, Town of Stonington and Town of 
Waterford. It was prepared by CDM for FEMA, under Contract No. EME-2003-CO-

 
7 
0340, and by Ocean and Coastal Consultants, Inc. for CDM, under Contract No. 2809-999-
003-CS. 
 
Base map information shown on the original countywide FIRM was derived from digital 
orthophotography. Base map files were provided in digital form by the Connecticut 
Department of Environmental Protection.  Ortho imagery was produced at a scale of 
1:12,000. Aerial photography is dated 2000, 2004 and 2005.  The projection used in the 
preparation of this map was Connecticut State Plane zone (FIPSZONE0600). The 
horizontal datum was NAD83, GRS1980 spheroid. 
 
August 2013 Coastal Study Update 
 
The coastal wave height analysis for this countywide coastal study was prepared by the 
Strategic Alliance for Risk Reduction (STARR) for FEMA under Contract No. 
HSFEHQ-09-D-0370 and completed in July 2011. This new analysis resulted in revisions 
to the FIRM for the Town of East Lyme, City of Groton, Groton Long Point Association, 
Town of Groton, Noank Fire District, Town of Old Lyme, City of New London, Borough 
of Stonington, Town of Stonington and Town of Waterford. 
 
Base map information shown on FIRM panels produced for this revision was derived 
from digital orthophotography. Base map files were provided in digital form by the 
Connecticut Department of Environmental Protection.  Ortho imagery was produced at a 
scale of 1:12,000. Aerial photography is dated 2000, 2004 and 2005.  The projection used 
in the preparation of this map was Connecticut State Plane Feet zone (FIPSZONE0600). 
The horizontal datum was NAD83, GRS1980 spheroid. 
 
1.3 
Coordination 
 
The purpose of an initial Consultation Coordination Officer’s (CCO) meeting is to 
discuss the scope of the FIS.  A final meeting is held to review the results of the study.  
 
The dates of the initial, intermediate and final CCO meetings held for the incorporated 
communities within New London County are shown in Table 1, “CCO Meeting Dates for 
Precountywide FIS.” 
 
TABLE 1 – CCO MEETING DATES FOR PRECOUNTYWIDE FIS 
Community Name 
Initial CCO Date 
Intermediate CCO Date 
Final CCO Date 
 
 
 
 
Town of Bozrah 
August 3, 1992 
* 
* 
Town of Colchester 
July 18, 1988 
* 
* 
Town of East Lyme 
* 
* 
   November 18,1994 
Town of Franklin 
November 1978 
* 
January 29, 1981 
Town of Griswold 
March 19, 1978 
November 26, 1980 
   October 20, 1983 
Town of Groton 
June 8, 1977 
January 11, 1979 
April 19, 1983 
Groton Long Point 
Association 
* 
* 
 September 30, 1981 
City of Groton 
* 
* 
April 20, 1983 
 
 
 
 
*Data not available 
 
 
 

 
8 
 
 
 
 
TABLE 1 – CCO MEETING DATES FOR PRECOUNTYWIDE FIS - continued 
Community Name 
Initial CCO Date 
Intermediate CCO Date 
Final CCO Date 
 
Borough of Jewett City 
* 
* 
March 28, 1984 
Town of Lebanon 
February 5, 1985 
December 1986 
May 7, 1987 
Town of Ledyard 
March 22, 1978 
* 
May 1, 1980 
Town of Lisbon 
May 12, 1978 
November  25, 1980 
October 20, 1983 
Town of Lyme 
March 1975 
November 1975 
November  3, 1976 
Town of Montville 
July 15, 1993 
* 
November 18, 1994 
City of New London 
* 
* 
* 
Noank Fire District 
* 
* 
January 14, 1983 
Town of North Stonington 
April 13, 1978 
March 5, 1980 
April 26, 1984 
City of Norwich 
April 21, 1992 
* 
* 
Town of Old Lyme 
* 
* 
March 30, 1983 
Town of Preston 
April 14, 1978 
November 25, 1980 
October 19, 1983 
Town of Salem 
November 1978 
* 
March 24, 1981 
Town of Sprague 
April 13, 1978 
December  9, 1980 
October 20, 1983 
Town of Stonington 
* 
* 
February 25, 1983 
Borough of Stonington 
* 
* 
January 13, 1983 
Town of Voluntown 
February 5, 1985 
December 1986 
May 7, 1987 
Town of Waterford 
May 1, 1985 
* 
May 31, 1989 
 
 
 
 
*Data not available 
 
 
For the July 18, 2011 Countywide FIS, the initial CCO meetings were held on October 24 
and 25 of 2006 and were attended by representatives of FEMA, USACE, Connecticut 
Department of Transportation (DOT), Southeastern Connecticut Council of Governments 
(SCCOG), Connecticut Department of Environmental Protection (DEP), University of 
Connecticut (UCONN), Natural Resources Conservation Service (NRCS), CDM, and 
New London County communities. 
 
The results of the July 18, 2011 study were reviewed at the final CCO meeting held on 
Wednesday, July 15, 2009, and attended by representatives of Town of Montville, Town 
of Colchester, Town of Lebanon, Town of East Lyme, Town of Salem, Town of Preston, 
Groton Long Point Association, Town of Waterford, Town of Groton, City of Norwich, 
Town of North Stonington, Town of Griswold, City of New London, Town of Old Lyme, 
Town of Sprague, Town of Franklin and Town of Voluntown. All problems raised at that 
meeting have been addressed in the July 18, 2011 study. 
 
For this 2013 coastal study revision, letters were sent to all communities within the 
county notifying them of the scope of the FIS, and soliciting pertinent information from 
them. Letters were mailed on April 28, 2010. The results of this countywide study were 
reviewed at the final CCO meetings held on January 17, 2012, and attended by 
representatives of the communities, the Connecticut Department of Energy and 
Environmental Protection (DEEP), FEMA Regional Service Center (RSC), FEMA, and 
STARR. All problems raised at that meeting were addressed in this study. 
 

 
9 
 
2.0 
AREA STUDIED 
 
2.1 
Scope of Study 
 
 
 
This FIS report covers the geographic area of New London, Connecticut.  The areas 
studied by detailed methods were selected with priority given to all known flood hazards 
and areas of projected development or proposed construction. 
 
July 18, 2011 Countywide FIS: 
 
All or portions of the flooding sources listed in Table 2 were studied by detailed methods. 
   
TABLE 2 – FLOODING SOURCES STUDIED BY DETAILED METHODS 
Flooding Source Name 
Description of Study Reaches 
 
 
Amston Lake 
For the entire shoreline within the Town of
Lebanon 
 
Beaver Brook (Town of Lyme) 
From its confluence with Eight Mile River to
approximately 6,075 feet  upstream of Route
156 
 
Beaver Brook (Town of Sprague) 
From its confluence with the Shetucket River
to the Sprague-Franklin corporate limits 
 
Birch Plain Creek 
From its confluence with Baker Cove to just
upstream of the Town of Groton-City of
Groton corporate limits  
 
Blissville Brook 
From its confluence with the Shetucket River
to approximately 400 feet upstream of Ames
Road 
 
Bobbin Mill Brook 
From its confluence with the Yantic River to
just upstream of Scotland Road in the City of
Norwich 
 
Connecticut River 
Storm tides from Long Island Sound that affect
Connecticut River in the Town of Lyme 
 
Day Meadow Brook 
From River Road to a point approximately
3,800 feet upstream  (near State Route 2) 
 
Denison Brook 
From State Route 138 to Fish Road 
 
East Branch Eight Mile River 
From approximately 900 feet downstream of
Darling Road to the confluence of Harris Brook
 

 
10 
 
TABLE 2 – FLOODING SOURCES STUDIED BY DETAILED METHODS – continued
 
 
Flooding Source Name 
Description of Study Reaches 
 
 
Eccleston Brook 
From 4,800 feet upstream of State Route 215 to
6,150 feet upstream of State Route 215 
 
Eight Mile River 
From its confluence with the Connecticut River
to just upstream of Route 156 
 
Fishers Island Sound 
* 
 
Fishtown Brook 
From Fishtown Road to U.S. Route 1 
 
Flat Brook 
From its confluence with Mill Cove to
approximately 100 feet upstream of Baldwin
Hill Road 
 
Ford Brook 
From its confluence with Trading Cove Brook
to approximately 100 feet upstream of Newton
Street 
 
Fort Hill Brook 
From Mumford Cove to Interstate 95 
 
Fourmile River 
From its confluence with Long Island Sound to
Boston Post Road 
 
Gardner Brook 
From its confluence with the Yantic River to a
point approximately 13,700 feet upstream 
 
Glasgo Pond 
Within the Town of Griswold 
 
Goldmine Brook 
From its confluence with Trading Cove Brook
to approximately 100 feet  upstream of Salem
Turnpike 
 
Great Meadow Brook 
From its confluence with Pachaug River  to
approximately 4,850 feet  upstream of Wyle
School Road 
 
Great Plain Brook 
From its confluence with Trading Cove Brook
to approximately 700 feet upstream of Norman
Road 
 
 
 
* Detailed study reaches for coastal areas are superseded by the August 2013 Coastal 
Study Update. See coastal sections for more information. 
 

 
11 
TABLE 2 – FLOODING SOURCES STUDIED BY DETAILED METHODS – continued 
 
Flooding Source Name 
Description of Study Reaches 
 
 
Green Fall River 
From 2,100 feet upstream of Wellstown Road 
in the Town of Hopkinton, Washington County, 
Rhode Island, to Clarks Falls Pond Dam 
 
Harris Brook 
From its confluence with East Branch Eight 
Mile River to approximately 4,500 feet 
upstream of dam 
 
Hunter Brook 
From the confluence with the Shetucket River 
to approximately 1,800 feet upstream of the 
second crossing of Hunters Road 
 
Jeremy River 
From 4,600 feet upstream of State Route 149 to 
Old Hartford Road 
 
Joe Clark Brook 
From its confluence with Poquetanuck Cove to 
a point approximately 7,600 feet upstream from 
the Preston-Ledyard corporate limits 
 
Jordan Brook 
From its confluence with Jordan Cove to 
approximately 1,600 feet  upstream from 
Douglas Lane 
 
 
  
Judd Brook 
From Old Hebron Road to approximately 2,350 
feet upstream of Norwich Avenue 
 
Latimer Brook 
From its confluence with Niantic River to 
approximately 400 feet upstream of Beckwith 
Road 
 
Little River 
From its confluence with the Shetucket River to 
approximately 2,750 feet upstream of State 
Route 138 
 
Long Island Sound 
* 
 
Long Island Sound and Connecticut River 
* 
 
Long Island Sound and Thames River 
* 
 
 
* Detailed study reaches for coastal areas are superseded by the August 2013 Coastal   
Study Update. See coastal sections for more information. 
 

 
12 
TABLE 2 – FLOODING SOURCES STUDIED BY DETAILED METHODS – continued 
 
Flooding Source Name 
Description of Study Reaches 
 
 
Meadow Brook   
From its confluence with Jeremy River to a 
point approximately 3,250 feet upstream of 
State Route 16 
 
Nevins Brook 
From its confluence with Jordan Brook to 
approximately 4,950 feet upstream of Fog Plain 
Road 
 
Niantic River 
Within the Town of East Lyme 
 
Norwichtown Brook 
From its confluence with the Yantic River to 
approximately 550 feet upstream of Case Street
 
Oxoboxo Brook 
From Horton Cove to Rockland Pond Dam 
 
Pachaug Pond 
Within the Town of Griswold 
 
Pachaug River 
From its confluence with Quinebaug River to 
its confluence with dam at Pachaug Pond 
 
Pachaug River (Town of Voluntown) 
From a point approximately 800 feet upstream 
of Carol Road to 5,000 feet upstream of Beach 
Pond Dam 
 
Pattagansett River 
From its confluence with Long Island Sound to 
Pattagansett Lake Dam 
 
Pawcatuck River 
From 31,000 feet upstream of the confluence 
with Little Narragansett Bay to the North 
Stonington, 
Connecticut-Hopkinton, 
Rhode 
Island boundary 
 
Pine Swamp Brook 
From its confluence with Thames River to 
approximately 1,300 feet upstream of Harvard 
Terrace 
 
Poquetanuck Cove 
From its confluence with the Thames River to 
the confluence of Joe Clark Brook 
 
Quinebaug River 
From its confluence with the Shetucket River to 
the Lisbon, New London County-Canterbury, 
Windham County boundary 
 
Red Cedar Lake 
For its entire length 
 

 
13 
TABLE 2 – FLOODING SOURCES STUDIED BY DETAILED METHODS – continued 
 
Flooding Source Name 
Description of Study Reaches 
 
 
Shewville Brook 
From 10,650 upstream of its  confluence with 
Hewitt Brook to approximately 750 feet 
upstream of Shewville Road 
 
Shetucket River 
From 16,000 feet upstream of Route 2A to 
approximately 300 feetupstream of North Main 
Street in the Town of Sprague 
 
Shunock River 
From its confluence with the Pawcatuck River 
to approximately 5,200 feet upstream of Main 
Street 
 
Spaulding Pond Brook 
From its confluence with Shetucket River to 
approximately 150 feet upstream of dam 
 
Susquetonscut Brook (Town of Franklin) 
From 2,000 feet upstream of its confluence 
with the Yantic River to Champion Road 
 
Susquetonscut Brook (Town of Lebanon) From 15,000 feet upstream of its confluence 
with the Yantic River to Bender Road 
 
Tenmile River 
From its confluence with the Willimantic River 
upstream to Palmer Pond 
 
Thames River and Shetucket River 
From just downstream of the Town of 
Montville-City of Norwich corporate boundary 
to just upstream of its confluence with Yantic 
River 
 
Trading Cove Brook 
From its confluence with the Thames River to 
approximately 300 feet upstream of the 
confluence with Goldmine Brook 
 
Tributary A 
From its confluence with Birch Plain Creek 
approximately 2,070 feet upstream of Tower 
Road 
 
Tributary B 
From its confluence with the Yantic River to 
approximately 
75 
feet 
upstream 
of 
Mediterranean Lane 
 
Tributary C 
From its confluence with Shetucket River to 
approximately 60 feet upstream of the Main 
Street Culvert 
 

 
14 
TABLE 2 – FLOODING SOURCES STUDIED BY DETAILED METHODS – continued 
 
Flooding Source Name 
Description of Study Reaches 
 
 
Tributary D 
From its confluence with the Shetucket River to 
approximately 600 feet upstream of Saint Regis 
Avenue 
 
Tributary E 
Within the City of Norwich 
 
Tributary F 
From its confluence with Thames River to 
Albert Street 
 
Whitford Brook (Town of Groton) 
From its confluence with Mystic River to the 
Groton-Stonington corporate limits 
 
Whitford Brook 
From approximately 1,800 feet upstream of 
Lantern Hill Road to approximately 400 feet 
upstream of the second crossing of Lantern Hill 
Road 
 
Williams Brook 
From approximately 750 feet upstream of its 
confluence with Whitford Brook Swamp to 
approximately 4,950 feet upstream of Town 
Farm Drive 
 
Williams Pond 
For its entire length 
 
Yantic River 
From its confluence with Thames River to 
Sisson Road 
 
Yantic River East Channel 
From approximately 1,000 feet upstream of its 
confluence 
with 
the 
Thames 
River 
to 
approximately 3,700 feet upstream 
 
 
Tributary E was studied in detail: however, no flooding is shown on the FIRM because 
the floodplains were less than 200 feet wide. 
 
Approximate analyses were used to study those areas having a low development potential 
or minimal flood hazards.  The scope and methods of study were proposed to, and agreed 
upon, by FEMA and the individual communities within New London County. For the 
July 18, 2011 countywide revision, no new approximate studies were executed.  All or 
portions of the flooding sources listed in Table 3, “Flooding Sources Studied by 
Approximate Methods,” were studied by approximate methods in the precountywide 
FISs. 
 
 
 

 
15 
TABLE 3 – FLOODING SOURCES STUDIED BY APPROXIMATE METHODS 
Flooding Source Name 
Community 
 
 
Adams Brook 
Sprague 
Amos Lake  
Preston 
Ashwillet Brook 
North Stonington 
Assekonk Brook 
North Stonington 
Avery Pond 
Preston 
Ayer Pond 
Preston 
Babcock Pond 
Colchester 
Bailey Pond 
Voluntown 
Baltic Reservoir 
Sprague 
Bartlett Brook 
Lebanon 
Bates Pond 
Preston 
Beaver Brook 
East Lyme, Franklin 
Beaver Dam Brook 
East Lyme, Groton (Town) 
Beebe Pond 
Groton (Town) 
Bentley Brook 
Bozrah 
Billings Avery Brook 
Ledyard 
Billing's Brook 
Griswold 
Bindloss Brook 
Groton (Town) 
Blissville Brook 
Lisbon 
Bog Meadow Reservoir 
Norwich 
Bogue Brook 
Montville 
Then Brandegee Lake 
Waterford 
Brewster Pond 
Lebanon 
Bride Brook 
East Lyme 
Broad Brook 
Preston 
Burton Brook 
Griswold 
Byron Brook 
Norwich 
Cabin Brook 
Colchester 
Cedar Swamp 
Preston, Voluntown 
Choate Brook 
Preston 
Church Brook 
Waterford 
Clayville Pond 
Griswold 
Cold Brook 
Franklin 
Cold Brook 
Norwich 
Cooks Pond 
Preston 
Cote Pond 
Norwich 
Cranberry Meadow Brook 
East Lyme 
Crooked Brook 
Griswold 
Crowley Brook 
Preston 
Dawley Pond 
Voluntown 
Deep Hollow  Brook 
Montville 
Deep River 
Lebanon 
Deep River Reservoir 
Colchester 
Denison Brook 
Voluntown 
Dickinson Creek 
Colchester 
 

 
16 
TABLE 3 – FLOODING SOURCES STUDIED BY APPROXIMATE METHODS - continued
Flooding Source Name 
Community 
 
 
Doaneville Pond 
Griswold 
Douglas Swamp 
Voluntown 
East Branch Eight Mile River 
Lyme, Salem 
Eccleston Brook (upper portions) 
Groton (Town) 
Elisha Brook 
Norwich 
Exeter Brook 
Lebanon 
Fairview Reservoir 
Norwich 
Falls Brook 
Montville 
Fenger Brook 
Waterford 
Fishtown Brook (upper portions) 
Groton (Town) 
Folwix Brook 
Preston 
Fort Hill Brook (upper portions) 
Groton (Town) 
Fox Brook 
Montville 
Gagers Pond 
Franklin 
Gardner Lake 
Bozrah 
Gay Pond 
Preston 
Glade Brook 
North Stonington 
Goldmine Brook 
Norwich 
Grassy Hill Brook 
Lyme 
Great Brook 
Groton (Town) 
Great Meadow Brook 
Voluntown 
Green Fall Pond 
Voluntown 
Green Fall River 
Voluntown 
Green Swamp Brook 
Waterford 
Haleys Brook 
Ledyard, Groton (Town) 
Hall Brook 
Colchester, Lebanon 
Hallville Pond 
Preston 
Hampstead Brook 
Groton (Town) 
Hanover Reservoir  
Sprague 
Harris Brook 
Salem 
Hatching House Brook 
Groton (Town) 
Havey Brook 
Griswold 
Hazard Pond 
Voluntown 
Hetchel Swamp Brook 
North Stonington 
Hewitt Brook 
Preston 
Hunts Brook 
Montville, Waterford 
Indiantown Brook 
Ledyard, Preston 
Jeremy River 
Colchester 
Jordan Brook 
Lebanon 
Judd Brook 
Colchester 
Kahn pond and adjacent pond areas 
Franklin 
Koistenen Brook 
Voluntown 
Lake of Isles Brook 
North Stonington, Preston 
Lakes Pond Brook 
Waterford 
Lantern Hill Brook 
Ledyard 
Lantern Hill Pond 
North Stonington 

 
17 
TABLE 3 – FLOODING SOURCES STUDIED BY APPROXIMATE METHODS - continued
Flooding Source Name 
Community 
 
 
Latimer Brook 
Montville, Salem 
Ledyard Lake 
Ledyard 
Lee Brook 
Ledyard 
Lewis Pond 
Preston 
Lisbon Brook 
Lisbon 
Lowden Brook 
Voluntown 
Main Brook 
North Stonington, Preston 
McAlpine  Brook 
Montville 
McCarthy Brook (NE of Baltic Road) 
Franklin 
Meadow Brook 
Colchester 
Mill Brook 
Griswold 
Miller Brook 
North Stonington, Preston 
Mineral Spring Brook 
Bozrah 
Mohegan Brook 
Montville 
Morgan Pond 
Ledyard 
Mount Misery Brook 
Voluntown 
Mountain Brook 
Franklin 
Myers Brook 
Preston 
Myron Kinney Brook 
Voluntown 
Nelkin Brook   
Colchester 
Norwich Pond 
Lyme 
Norwichtown Brook 
Norwich 
Oil Mill Brook 
Waterford 
Papermill Pond 
Sprague 
Pattagansett River 
East Lyme 
Pease Brook 
Franklin, Lebanon 
Pendleton Hill Brook 
North Stonington 
Phelps Brook 
North Stonington 
Pine Brook 
Colchester 
Poquetanuck Brook 
Preston 
Prentice Brook 
North Stonington 
Rattlesnake Brook 
Griswold, Preston 
Red Brook 
East Lyme 
Red Brook 
Ledyard, Groton (Town) 
Roaring Brook 
Lyme 
Rogers Lake 
Lyme 
Rosemond Lake 
Ledyard 
Round Brook 
Bozrah 
Salmon River 
Colchester 
Savin Lake 
Lebanon 
Sheep Barn Brook 
Griswold 
Sherman Brook 
Lebanon 
Shetucket River 
Sprague 
Shewville Brook 
Preston 
Spaulding Pond Brook 
Norwich 
Spinnging Mill Brook 
Lebanon 

 
18 
TABLE 3 – FLOODING SOURCES STUDIED BY APPROXIMATE METHODS - continued
Flooding Source Name 
Community 
 
 
Stone Hill Reservoir 
Griswold 
Stony Brook 
Montville, Waterford 
Susquetonscut Brook 
Franklin 
Swamp area along Hartshorn Brook 
Franklin 
Swamp area along Norwich Lebanon Road southeast 
of Brush Hill Road 
Franklin 
Swamp area at the southern end of Bellows Brook 
Franklin 
Swamp area northeast of the intersection of 
Champion Road and State Route 87 
Franklin 
Swamp area northeast of the intersection of Kahn 
Road and Blue Hill Road 
Franklin 
Swamp area south of Turkey Hill 
Franklin 
Tadman Pond 
Bozrah 
Taftville Reservoir 
Norwich 
Tenmile River 
Lebanon 
The Fourmile River 
East Lyme 
Thompson Brook 
Ledyard 
Trading Cove Brook 
Bozrah, Montville 
Tributary A (upper portions) 
Groton (Town) 
Uncas Pond 
Lyme 
West Branch Brook 
Ledyard 
West Branch Red Brook 
Groton (Town) 
Whalebone Creek 
Lyme 
Whittle Brook 
Montville 
Wood River 
Voluntown 
Wyassup Brook 
North Stonington 
Yantic River 
Lebanon 
Yawkucs Brook 
North Stonington 
 
No new detailed-studies were performed for the July 18, 2011 countywide FIS. 
 
Detail-studied streams that were not re-studied as part of this revision may include a 
profile baseline on the FIRM.  The profile baselines for these streams were based on the 
best available data at the time of their study and are depicted as they were on the previous 
FIRMs.  In some cases the transferred profile baseline may deviate significantly from the 
channel or may be outside of the floodplain. 
 
As part of the July 18, 2011 countywide FIS, redelineation of coastal flood hazard data 
was performed for open water flooding sources in the communities of Town of East 
Lyme, City of Groton, Groton Long Point Association, Town of Groton, Noank Fire 
District, Town of Old Lyme, City of New London, Borough of Stonington, Town of 
Stonington and Town of Waterford. It was prepared by CDM for FEMA, under 
Contract No. EME-2003-CO-0340, and by Ocean and Coastal Consultants, Inc. for CDM, 
under Contract No. 2809-999-003-CS. This study was completed July 11, 2008. This 
study has been superseded by the August 2013 Coastal Study Update. 
 

 
19 
The July 18, 2011 FIS also incorporates the determinations of letters issued by FEMA 
resulting in map changes (Letter of Map Revision [LOMR], Letter of Map Revision - 
based on Fill [LOMR-F], and Letter of Map Amendment [LOMA]), as shown in Table 4, 
“Letters of Map Change.” 
 
TABLE 4 – LETTERS OF MAP CHANGE 
Community 
Case Number 
Flooding Source 
Letter Date 
 
 
 
 
East Lyme, Town of 
93-01-003P 
Niantic Bay 
02/261993 
Groton, Town of 
96-01-051P 
Haleys Brook, West 
Branch Red Brook 
01/20/1997 
East Lyme, Town of 
97-01-051P 
Pattagansett River 
02/21/1999 
Norwich, City of 
03-01-077P 
Great Plain Brook 
01/16/2004 
New London, City of 
05-01-0174P 
Thames River 
04/19/2005 
Colchester, Town of 
09-01-1230P 
Unnamed Tributary To 
Sherman Brook 
02/15/2010 
 
August 2013 Coastal Study Update 
 
The coastal wave height analysis for this countywide coastal study was prepared by 
STARR. This new analysis resulted in revisions to the FIRM for the Borough of 
Stonington, Groton Long Point Association, Noank Fire District, Cities of Groton and 
New London and Towns of East Lyme, Groton, Old Lyme, Stonington and Waterford. 
 
2.2 
Community Description 
 
New London County is located in southeast Connecticut.  In New London County, there 
are nineteen (19) towns, three (3) cities, and two (2) boroughs. The Towns of Colchester, 
Franklin, Griswold, Lebanon, Lisbon, Sprague, Voluntown, and the Borough of Jewett 
City are located in northern New London County.  The Towns of Bozrah, Ledyard, 
Montville, North Stonington, Preston, Salem, and the City of Norwich are in the central 
portion of the county. The Towns of East Lyme, Lyme, Old Lyme, Stonington, 
Waterford, the Cities of Groton and New London, Groton Long Point Association, the 
Borough of Stonington, and the Noank Fire District are located in the southern portion of 
the county. The Pequot Indian Reservation is located in the Town of North Stonington. 
 
New London County is bordered on the north by Windham County, Connecticut, and on 
the west by Middlesex County, Connecticut. It is bordered on the northwest by the 
Counties of Tolland and Hartford, Connecticut. New London County is bordered on the 
east by Washington County, Rhode Island. It is bordered on the south by Fishers Island 
Sound and Long Island Sound. 
 
According to the 2010 US Census, the population of New London County was 274,055 
(Reference 1).  The total land area in New London County consists of 665.91 square 
miles (sq. mi.).   
 
The terrain of New London County is mostly level, becoming more elevated only in its 
northern extreme. The topography then ranges from gently rolling terrain in the valleys to 
steep hilly terrain in several upland areas.  The highest point in the county is Gates Hill in 

 
20 
the Town of Lebanon at approximately 660 feet above sea level, and the lowest point is 
sea level (Reference 2).  
 
The land area of the county consists primarily of soil developed on till and bedrock in the 
uplands. Glacial deposits, and the erosion of these deposits by running water from glacial 
melt, have created an irregular earth surface in some areas. The most common soils in 
New London County are loams formed on glacial till. The remainder of the soils are 
alluvial, formed on glacial outwash or floodplains. The bedrock in this area of 
Connecticut is predominantly unweathered gneiss and schist overlain by glacial till or 
outwash. The soils were formed from glacial till, outwash and wind-blown deposits. 
Glacial deposits over bedrock are primarily of two types: nonstratified material or till 
composed of clay, sand, gravel, and boulders, intermingled; and stratified material 
composed of sand and gravel. These soils are deep and well drained with moderate to 
moderately rapid permeability. The characteristics of these soils facilitate precipitation 
retention where the hills are slightly to moderately sloped.  The result is numerous 
streams, valleys, hills, steep slopes, inland wetlands, lakes, ponds, and bedrock 
outcroppings (Reference 3). 
 
Outside the residential, commercial, and industrial areas, the vegetation is composed 
primarily of trees and undergrowth in woodlands, grasses in the open fields and pastures, 
farm crops in the few fields devoted to agriculture, and various swamp plants in the 
inland wetlands. Woodlands predominate, especially on slopes and summits of the many 
hills. In the woodlands, hardwoods far outnumber the softwoods. 
 
New London County is part of the Coastal Lowlands that cover the entire New England 
Coast.  The Connecticut Coastal Lowlands form a narrow strip of land, 6 to 16 miles 
wide, that runs along the southern shore of New London County at Long Island Sound. 
The Coastal Lowlands are characterized by lower ridges and beaches and harbors along 
the coast (Reference 4). 
 
The County of New London has many rivers and brooks, some of which flow to Long 
Island Sound. The Thames River, which flows south into Long Island Sound, is one of 
the principal rivers in Connecticut. Although the Thames River is only 15 miles long, the 
basin extends approximately 75 miles north, with the Shetucket and Quinnebaug Rivers 
being the main contributing sources of water. The drainage area of the Thames River 
basin is 1,478 square miles.  
 
The climate of the county is relatively mild compared to the rest of New England, with 
relatively mild winters and warm summers. The mean annual temperature for the county 
is 50 degrees Fahrenheit (ºF). Generally, summer temperatures range from 70°F to 90 ºF; 
temperatures over 100 ºF do occur, but infrequently. Winter temperatures range between 
10 ºF and 40 ºF. The prevailing winds are northwesterly in the winter and southwesterly 
in the summer. Hurricanes occur most frequently during the months of August, 
September, and October. The average annual precipitation is 46 inches. 
 
2.3 
Principal Flood Problems 
 
Floods in the New London County have occurred in every season of the year. Floods in 
late summer and fall are usually the result of hurricanes or other storms moving northeast 

 
21 
along the Atlantic coast. The most severe flooding occurs during hurricanes or coastal 
storms. These storms, with their intense winds and rainfall, can create abnormally high 
tidal surges, wave runup, and peak runoff. The low-lying tidal shoreline areas of New 
London County are subjected to periodic flooding by severe storms. The shoreline along 
Long Island Sound, with its high concentration of residential structures, is highly 
susceptible to heavy damage. When the hurricane's track is west of the coastal 
communities, the hurricane's counterclockwise winds tend to increase the adverse effect 
of the tidal surge.  
 
Winter floods result from occasional thaws, particularly in years of heavy snowfall. 
Flooding has also occurred in early spring when the ground was frozen. Spring floods are 
common and are caused by rainfall in combination with snowmelt. When coastal storms 
occur in winter and spring, the flooding problem is compounded by ice jams and runoff 
from melting snow. 
 
Historic flooding in eastern Connecticut extends back to the early 17th century. The two 
earliest hurricanes of record in New England, namely August 15, 1635, and August 3, 
1638, created flood levels apparently higher than the recent floods of 1938 and 1954, and 
probably were the greatest experienced in New England during the past 300 years 
(Reference 5). Though no records exist for Connecticut, it is reasonable to assume that 
these hurricanes also caused extensive tidal flooding along the Connecticut coast. 
Records indicate that the coast of Connecticut has experienced hurricane tidal flooding on 
over 60 occasions since 1769. On nine of these occasions, severe tidal flooding occurred. 
The five greatest, as far as can be determined from existing records, were the hurricanes 
of 1938, 1893, 1954, 1815, and 1944 (in descending order of estimated magnitude). 
Historical information regarding flood problems due to hurricanes is included in the 
USACE study entitled, “Hurricane Survey, Connecticut Coastal and Tidal Areas” 
(Reference 6).  
 
The hurricanes of 1938 and 1954 caused some of the worst flooding in New London 
County.  The 1938 hurricane resulted in the greatest disaster in Connecticut's history up 
to that time, because of the combined effects of flooding, gale winds, and storm surge.  
The tide was high when the storm surge struck and resulted in a maximum tidal elevation 
of 8.8 feet. The recurrence interval of this flood height is approximately 2.2-percent-
annual-chance. The hurricane of 1954 moved up the Atlantic coast and entered 
Connecticut in the New London area causing a maximum tidal elevation of 8.0 feet, with 
a recurrence interval of approximately 5-percent-annual-chance (Reference 7). Tidal 
surges during severe storms cause flooding along both the Niantic and the Thames 
Rivers, the larger rivers in the area, and along other smaller streams flowing into either 
these rivers or Long Island Sound.  Where structures are located in the floodplains, 
damage occurs.  In Waterford, hurricane tidal flood damages for the 1938 and 1954 
hurricanes were scattered along the entire shoreline, with principal concentrations at the 
head of Niantic Bay and in the Ridgewood area on the west bank of Alewife Cove. Much 
of the loss in 1954 was from damage to boats (Reference 6).   
 
Shoreline damages in the Town of East Lyme resulted in losses of $1,070,000 and 
$990,000 during the 1938 and 1954 hurricanes, respectively (Reference 6). In addition, 
the Town of Montville suffered losses of $900,000 and $700,000 during the 1938 and 
1954 hurricanes, respectively due to shoreline damages.  At the CCO meetings for the 

 
22 
March 1979 study for the Town of East Lyme, comments were made regarding repeated 
coastal and riverine flooding. Tidal flooding occurs along Shore Drive, Shore Road, and 
Atlantic Street, just off Niantic Bay. Also, tidal flooding was reported on both the east 
and west shores of Black Point. Flooding at Giants Neck Road because of Bride Brook 
overflowing its banks was reported.  
 
The September 1938 storm was the maximum flood of record for the Town of Norwich. 
If this flood were to occur at the present time, it would have an estimated recurrence 
interval of approximately 0.3-percent-annual-chance flood. During the September 1938 
flood, high water marks of 8 feet and 1 inch were recorded at the corner of Bath and 
Franklin Streets and ma