Item7_FEMA-FIS-and-FIRM-Update-Adoption — Grover Beach City Council, May 28, 2024

Agenda Item No. 7

CITY COUNCIL STAFF REPORT
TO: Honorable Mayor and City Council DATE: May 28, 2024 FROM: Matthew Bronson, City Manager
PREPARED BY: Greg Ray, Public Works Director/City Engineer Gabriel Munoz-Morris, Senior Engineer
SUBJECT: Adoption of Federal Emergency Management Agency Flood Insurance Study Report and Flood Insurance Rate Maps

RECOMMENDATION
Adopt a Resolution adopting the current effective Flood Insurance Study report and Flood Insurance Rate Maps prepared by the Federal Emergency Management Agency.

BACKGROUND
The Federal Emergency Management Agency (FEMA) prepares and distributes a Flood Insurance Study (FIS) report and Flood Insurance Rate Maps (FIRM) which detail areas subject to flooding. These documents are used as the basis for flood plain ordinances and flood insurance programs within local jurisdictions.

On September 28, 2021, FEMA presented communities in San Luis Obispo County with preliminary copies of the updated FIS report and FIRM for the entire county. The FIS report described the flood hazard information updates made to the FIRM and the sources of information used in making the updates. FEMA initiated a statutory 90-day appeal period, which is required in certain communities when FEMA adds or modifies Base (1-percent-annual-chance) Flood Elevations (BFEs), base flood depths, Special Hazard Flood Areas (SFHA), flood zone designations, or regulatory floodways within a community, as shown on the preliminary FIRM.

The 90-day appeal period was not required in Grover Beach as no modifications to the FIRM were made that warranted the review period. After the appeal period for San Luis Obispo County was completed and FEMA addressed all comments/appeals, FEMA prepared the final FIRM and FIS report for the county which will now be effective for Grover Beach on June 6, 2024.

The City is now required under the standards specified in 44 CFR Part 60.3 (d) and (e) of the National Flood Insurance Program (NFIP) to adopt the current FIS report and FIRM. Attachment 2 includes the full countywide FIS report and Attachment 3 shows the FIRM maps for Grover Beach though the FIS report and FIRM do not create or show any new impacts to properties within Grover Beach. Section 5.10.030 (B) of the City of Grover Beach Development Code titled “Basis for establishing the areas of special flood hazards” states that “The areas of special flood hazard identified by the Federal Emergency Management Agency (FEMA) in the “Flood Insurance Study (FIS) for San Luis Obispo County, California and Incorporated Areas” dated August 28, 2008, with accompanying Flood Insurance Rate Maps (FIRM’s) and Flood Boundary and Floodway Maps (FBFM’s), dated August 28, 2008, and all subsequent amendments and/or revisions, are hereby adopted by reference and declared to be part of this Section.” Through the recommended adoption of the updated FIS report and FIRM, the City will adopt the revision to the August 28, Staff Report: Federal Emergency Management Agency FIS and FIRM Adoption Page 2 May 28, 2024

2008 maps as a basis for establishing requirements of Section 5.10 of the Development Code for Flood Hazard Area Use Control.

FISCAL IMPACT
This recommended action has no fiscal impact.

ALTERNATIVES
The Council has the following alternatives to consider:

1. Adopt a Resolution adopting the current effective Flood Insurance Study report and Flood Insurance Rate Maps prepared by the Federal Emergency Management Agency; or,

2. Provide alternative direction to staff.

PUBLIC NOTIFICATION
The agenda was posted in accordance with the Brown Act.

Attachments

1. Resolution No. 24-XX

2. Flood Insurance Study

3. Flood Insurance Rate Maps for Grover Beach
Attachment 1
RESOLUTION NO. 24-__

A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF GROVER BEACH,

CALIFORNIA ADOPTING THE FEDERAL EMERGENCY MANAGEMENT

AGENCY FLOOD INSURANCE STUDY REPORT AND FLOOD INSURANCE RATE MAPS EFFECTIVE JUNE 4, 2024
WHEREAS, The Federal Emergency Management Agency (FEMA) creates and routinely updates a Flood Insurance Study (FIS) report and Flood Insurance Rate Maps (FIRM) for the County of San Luis Obispo and incorporated areas; and
WHEREAS, The City of Grover Beach is required to adopt updated FIS reports and FIRMs when finalized by FEMA as part of its flood plane management ordinances; and WHEREAS, The City of Grover Beach adopted the previous FIS report and FIRM effective August 28, 2008; and
WHEREAS, FEMA has completed an update to the FIS report for San Luis Obispo County and incorporated areas effective June 4, 2024; and
WHEREAS, the updated FIS report and FIRM do not create any new impacts to real property in the City of Grover Beach; and
WHEREAS, the City of Grover Beach Development Code Section 5.10 references the FEMA FIS report and FIRM as the basis for establishing areas of special flood hazards within the City; and
WHEREAS, the City of Grover Beach Development Code Section 5.10 automatically incorporates the updated FIS report and FIRM effective June 4, 2024 by reference once adopted by the City Council.

NOW THEREFORE, BE IT HEREBY RESOLVED that the City Council of the City of Grover Beach HEREBY adopts the Flood Insurance Study report and Flood Insurance Rate Maps effective June 4, 2024.

On motion by Council Member __________, seconded by Council Member ________, and on the following roll-call vote, to wit:

AYES: Council Members –
NOES: Council Members –
ABSENT: Council Members –
ABSTAIN: Council Members –
RECUSED: Council Members –
the foregoing Resolution was PASSED, APPROVED, and ADOPTED at a regular meeting of the City Council of the City of Grover Beach, California this 28th day of May 2024.

KAREN BRIGHT, MAYOR
Attest:

WENDI B. SIMS, CITY CLERK
VOLUME OF 4
REVISED:

JUNE 6, 2024

SAN LUIS OBISPO

COUNTY, CALIFORNIA

TABLE OF CONTENTS
Volume 1
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 6 SECTION 2.0 – FLOODPLAIN MANAGEMENT APPLICATIONS 17

2.1 Floodplain Boundaries 17

2.2 Floodways 34

2.3 Base Flood Elevations 35

2.4 Non-Encroachment Zones 35

2.5 Coastal Flood Hazard Areas 36
SECTION 3.0 – INSURANCE APPLICATIONS 40

3.1 National Flood Insurance Program Insurance Zones 40 SECTION 4.0 – AREA STUDIED 40

4.1 Basin Description 40

4.2 Principal Flood Problems 41

4.3 Non-Levee Flood Protection Measures 43

4.4 Levees 46
SECTION 5.0 – ENGINEERING METHODS 49

5.1 Hydrologic Analyses 49

5.2 Hydraulic Analyses 62
Volume 2
SECTION 5.0 – ENGINEERING METHODS

5.4 Alluvial Fan Analyses 116
SECTION 6.0 – MAPPING METHODS 116

6.1 Vertical and Horizontal Control 116

6.2 Base Map 118

6.3 Floodplain and Floodway Delineation 119

6.4 Coastal Flood Hazard Mapping 158

6.5 FIRM Revisions 161
SECTION 7.0 – CONTRACTED STUDIES AND COMMUNITY COORDINATION 165

7.1 Contracted Studies 165

7.2 Community Meetings 176
SECTION 8.0 – ADDITIONAL INFORMATION 179
SECTION 9.0 – BIBLIOGRAPHY AND REFERENCES 180
Volume 1
Volume 2
Volume 1
Volume 2
Volume 3
Volume 4
Published Separately

FLOOD INSURANCE STUDY REPORT
SECTION 1.0 – INTRODUCTION

1.1 The National Flood Insurance Program
Criteria for Land Management and Use

1.2 Purpose of this Flood Insurance Study Report

1.3 Jurisdictions Included in the Flood Insurance Study Project 3 Table 1: Listing of NFIP Jurisdictions
Community CID
HUC-8
SubBasin(s) Located on FIRM Panel(s)
If Not
Included,
Location of
Flood
Hazard Data
Arroyo Grande, City
of 060305 18060006
06079C1363J 06079C1364G
06079C1368G 06079C1601J
06079C1602G 06079C1606G
Atascadero, City of 060700 18060005,
18060006
06079C0612G 06079C0613G
06079C0614G 06079C0618G
06079C0619G 06079C0826G
06079C0827G 06079C0828G1
06079C0829G 06079C0831G
06079C0832G 06079C0833G
06079C0834G 06079C0853G
El Paso De Robles,
City of 060308 18060004,
18060005
06079C0385H 06079C0387H
06079C0389H 06079C0391H
06079C0392H 06079C0393G
06079C0394H 06079C0425G
06079C0602G 06079C0604G
06079C0606G 06079C0607G
06079C0609F1
Grover Beach, City
of 060306 18060006 06079C1344J 06079C1363J 06079C1582J 06079C1601J Morro Bay, City of 060307 18060006
06079C0811H 06079C0813H
06079C0814G 06079C1026H
06079C1027H 06079C1028H
06079C1029H
Pismo Beach, City of 060309 18060006
06079C1337J 06079C1341H
06079C1343H 06079C1344J
06079C1363J
San Luis Obispo,
City of 060310 18060006
06079C1064G 06079C1065G
06079C1066G 06079C1067G
06079C1068G 06079C1069G
06079C1100G 06079C1330J
06079C1331H 06079C1332G
06079C1355G
San Luis Obispo
County,
Unincorporated
Areas
060304
18030003
18030012
18060003
18060004
18060005
18060006
18060007
18090008
06079C0011H 06079C0012H
06079C0014H 06079C0020H
06079C0050F1
06079C0075G
06079C0100G 06079C0125G
06079C0136H 06079C0137H
06079C0138H1
06079C0139H
06079C0143H 06079C0145H
06079C0175G 06079C0200F1
Table 1: Listing of NFIP Jurisdictions (continued)
4 San Luis Obispo
County,
Unincorporated
Areas
060304
18030003
18030012
18060003
18060004
18060005
18060006
18060007
18090008
06079C0225G 06079C0250F1
06079C0252H 06079C0254H
06079C0258H 06079C0260H
06079C0266H 06079C0267H
06079C0269H 06079C0286H
06079C0287H 06079C0288H
06079C0289H 06079C0293H
06079C0295H1
06079C0300H
06079C0325G 06079C0350G
06079C0375G1
06079C0377H
06079C0379H 06079C0380H
06079C0381H 06079C0383H
06079C0385H 06079C0387H
06079C0389H 06079C0390H1
06079C0391H 06079C0392H
06079C0393G 06079C0394H
06079C0425G 06079C0450G
06079C0475G 06079C0500F1
06079C0506H 06079C0507H
06079C0509H 06079C0528H
06079C0529G 06079C0530G
06079C0531F1
06079C0532F1
06079C0533G 06079C0534F1
06079C0536H 06079C0537H
06079C0539H 06079C0541G
06079C0543H 06079C0545H
06079C0575G 06079C0600G
06079C0602G 06079C0604G
06079C0605G 06079C0606G
06079C0607G 06079C0608G
06079C0609F1
06079C0611G
06079C0612G 06079C0613G
06079C0614G 06079C0616F1
06079C0617F1
06079C0618G
06079C0619G 06079C0630H
06079C0635H 06079C0640H1
06079C0641H 06079C0642H
06079C0643H 06079C0644H
06079C0675G 06079C0700G
06079C0725G 06079C0750F1
06079C0756H 06079C0757H
06079C0759H 06079C0776H
06079C0777H1
06079C0778H
06079C0779H 06079C0783H
06079C0784H 06079C0785G
06079C0792H 06079C0805G
06079C0810G1
06079C0811H
06079C0812G 06079C0813H
06079C0814G 06079C0816G
06079C0817G 06079C0818G
06079C0819G1
06079C0826G
06079C0828G1 06079C0829G
06079C0831G 06079C0832G
06079C0833G 06079C0834G
06079C0840G1
06079C0841G1
Table 1: Listing of NFIP Jurisdictions (continued)
5 06079C0842G 06079C0843G1
06079C0844G 06079C0851F1
06079C0852F1
06079C0853G
06079C0854G 06079C0857H
06079C0860H 06079C0861G
06079C0862G 06079C0863G
06079C0864G 06079C0870G
06079C0900G 06079C0925G
06079C0950G 06079C0975G
06079C1000F1
06079C1017H
06079C1019H 06079C1026H
06079C1027H 06079C1028H
06079C1029H 06079C1031G
06079C1032G 06079C1033G
06079C1034G 06079C1036H
06079C1040H 06079C1045G
06079C1055G1
06079C1060G
06079C1064G 06079C1065G
06079C1066G 06079C1067G
06079C1068G 06079C1069G
06079C1100G 06079C1125G
06079C1150G 06079C1175G
06079C1200G 06079C1225G
06079C1250G 06079C1275F1
06079C1282H 06079C1301H
06079C1302H1
06079C1303H
06079C1304H 06079C1308H
06079C1310H 06079C1316H
06079C1317H 06079C1319H1
06079C1328J 06079C1329J
06079C1330J 06079C1331H
06079C1332G 06079C1333F1
06079C1334F1 06079C1336J
06079C1337J 06079C1338H1
06079C1341H 06079C1342G
06079C1343H 06079C1344J
06079C1355G 06079C1360G
06079C1361G 06079C1362G
06079C1363J 06079C1364G
06079C1368G 06079C1370G
06079C1400G 06079C1425G
06079C1450G1
06079C1475G
06079C1500G 06079C1525G
06079C1550G 06079C1575G
06079C1582J 06079C1584H
06079C1592H 06079C1594H
06079C1601J 06079C1602G
06079C1603G 06079C1604G
06079C1606G 06079C1608G
06079C1610G 06079C1611H
06079C1613H 06079C1615H
06079C1616F1
06079C1617G
06079C1618G 06079C1619F
06079C1630G 06079C1635G
06079C1636G 06079C1637G
Table 1: Listing of NFIP Jurisdictions (continued)
6 06079C1638F 06079C1639F
06079C1641F106079C1642F1
06079C1643G 06079C1644F1
06079C1675G 06079C1700G
06079C1725G 06079C1750G
06079C1775G 06079C1800G
06079C1825G 06079C1850G
06079C1857H 06079C1859H
06079C1880F 06079C1885F
06079C1902F 06079C1905F
06079C1906F 06079C1910F
06079C1950F 06079C1975G
06079C2000G 06079C2025G
06079C2050F1
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-percent-annual-chance flood elevation is also referred to as the Base Flood Elevation (BFE)); delineations of the 1-percent-annual-chance and 0.2-percent-annual-chance floodplains; and 1-percent-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 30, “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 https://levees.sec.usace.army.mil/
Guide to Flood Maps
.
keer Coj ava N

Figure 2: FIRM Notes to Users

NOTES TO USERS
Figure 2. FIRM Notes to Users

NOTES FOR FIRM INDEX

SPECIAL NOTES FOR SPECIFIC FIRM PANELS
,
Figure 3: Map Legend for FIRM
SPECIAL FLOOD HAZARD AREAS:

Figure 3: Map Legend for FIRM

OTHER AREAS

FLOOD HAZARD AND OTHER BOUNDARY LINES

GENERAL STRUCTURES
Aqueduct
Channel
Culvert
Storm Sewer
Dam
Jetty
Weir
Bridge

NO SCREEN
Figure 3: Map Legend for FIRM

REFERENCE MARKERS

CROSS SECTION & TRANSECT INFORMATION

ZONE AE
(EL 16)

ZONE AO
(DEPTH 2)

ZONE AO
(DEPTH 2)
(VEL 15 FPS)

BASE MAP FEATURES
Missouri Creek
Figure 3: Map Legend for FIRM
4276000mE
365000 FT
80 16’ 52.5”
SECTION 2.0 – FLOODPLAIN MANAGEMENT APPLICATIONS

2.1 Floodplain Boundaries
Table 2: Flooding Sources Included in this FIS Report
Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued) Table 2: Flooding Sources Included in this FIS Report (continued)

2.2 Floodways
Figure 4: Floodway Schematic

2.3 Base Flood Elevations

2.4 Non-Encroachment Zones

2.5 Coastal Flood Hazard Areas

2.5.1 Water Elevations and the Effects of Waves
Astronomical tides
Storm surge
Freshwater inputs
Wave setup
Storm-induced erosion
Overland wave propagation
Wave runup
Wave overtopping
Figure 5: Wave Runup Transect Schematic

2.5.2 Floodplain Boundaries and BFEs for Coastal Areas

2.5.3 Coastal High Hazard Areas
Coastal High Hazard Area (CHHA)
Primary Frontal Dune (PFD)
Figure 6: Coastal Transect Schematic

2.5.4 Limit of Moderate Wave Action
SECTION 3.0 – INSURANCE APPLICATIONS

3.1 National Flood Insurance Program Insurance Zones
. Table 3: Flood Zone Designations by Community
SECTION 4.0 – AREA STUDIED

4.1 Basin Description
Table 4: Basin Characteristics
Table 4: Basin Characteristics (continued)
41 HUC-8
Sub-Basin
Name
HUC-8
Sub-Basin
Number
Primary
Flooding
Source Description of Affected Area
Drainage Area
(square miles)
Central
Coastal 18060006 PacificOcean
The basin runs along the
California coast through
Monterey and San Luis Obispo
Counties.
1,924
Cuyama 18060007 Cuyama
River
Located in northern Santa
Barbara, southern San Luis
Obispo, southwestern Kern,
and northwestern Ventura
Counties. It is a sparsely
inhabited area where land is
largely used for agriculture.
1,143
Estrella 18060004 Estrella
River
Located in the northern part of
San Luis Obispo County with a
portion located in Monterey
County. Some areas have
been developed, but the vast
majority of the land is
rangeland.
950
Middle KernUpper
TehachapiGrapevine
18030003 Kern River
Drains an area of the southern
Sierra Nevada mountains
northeast of Bakersfield.
2,617
Salinas 18060005 Salinas
River
The Salinas River drainage
basin runs from northern San
Luis Obispo County to its
discharge into the Pacific
Ocean at Monterey Bay.
3,330
Santa Maria 18060008 Santa
Maria River
Located in southern San Luis
Obispo County and northern
Santa Barbara County. The
watershed is dominated by
residential and agricultural land
uses.
684
Tulare Lake
Bed 18030012 Tulare Lake
Small portions of the western
side of the basin are located
on the east side of San Luis
Obispo County. The basin has
been developed extensively for
agriculture and petroleum
extraction. Only about 4% of
the basin area is urbanized.
3,786

4.2 Principal Flood Problems
Table 5 contains a description of the principal flood problems that have been noted for San Luis Obispo County by flooding source.

Table 5: Principal Flood Problems
. Table 6: Historic Flooding Elevations
[Not Applicable to this Flood Risk Project]

4.3 Non-Levee Flood Protection Measures
Table 7: Non-Levee Flood Protection Measures
Table 7: Non-Levee Flood Protection Measures (continued) Table 7: Non-Levee Flood Protection Measures (continued) Table 7: Non-Levee Flood Protection Measures (continued)

4.4 Levees

Table 8: Levees
SECTION 5.0 – ENGINEERING METHODS

5.1 Hydrologic Analyses

Table 9: Summary of Discharges (
Table 9: Summary of Discharges (Continued)
(
Table 9: Summary of Discharges (Continued)
(
Table 9: Summary of Discharges (Continued)
(
Table 9: Summary of Discharges (Continued)
(
Table 9: Summary of Discharges (Continued)
(
Table 9: Summary of Discharges (Continued)
(
Table 9: Summary of Discharges (Continued)
(
Table 9: Summary of Discharges (Continued) ( *
Figure 7: Frequency Discharge-Drainage Area Curves [Not Applicable to this Flood Risk Project] Table 10: Summary of Non-Coastal Stillwater Elevations
Table 11: Stream Gage Information used to Determine Discharges

5.2 Hydraulic Analyses
.

Table 12: Summary of Hydrologic and Hydraulic Analyses
Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) .

Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) .

Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) .

Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) .

Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) Table 12: Summary of Hydrologic and Hydraulic Analyses (continued) VOLUME OF 4

AND INCORPORATED AREAS

COMMUNITY NAME COMMUNITY
NUMBER
ARROYO GRANDE, CITY OF 060305
ATASCADERO, CITY OF 060700
EL PASO DE ROBLES, CITY OF 060308
GROVER BEACH, CITY OF 060306
MORRO BAY, CITY OF 060307
PISMO BEACH, CITY OF 060309
SAN LUIS OBISPO, CITY OF 060310

SAN LUIS OBISPO COUNTY,
UNINCORPORATED AREAS 060304
REVISED:

JUNE 6, 2024

FLOOD INSURANCE STUDY NUMBER
06079CV00 D
Version Number 2.6.3.6

SAN LUIS OBISPO

COUNTY, CALIFORNIA
i

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 6 SECTION 2.0 – FLOODPLAIN MANAGEMENT APPLICATIONS 17

2.1 Floodplain Boundaries 17

2.2 Floodways 34

2.3 Base Flood Elevations 35

2.4 Non-Encroachment Zones 35

2.5 Coastal Flood Hazard Areas 36

2.5.1 Water Elevations and the Effects of Waves 36

2.5.2 Floodplain Boundaries and BFEs for Coastal Areas 37

2.5.3 Coastal High Hazard Areas 38

2.5.4 Limit of Moderate Wave Action 39
SECTION 3.0 – INSURANCE APPLICATIONS 40

3.1 National Flood Insurance Program Insurance Zones 40 SECTION 4.0 – AREA STUDIED 40

4.1 Basin Description 40

4.2 Principal Flood Problems 41

4.3 Non-Levee Flood Protection Measures 43

4.4 Levees 46
SECTION 5.0 – ENGINEERING METHODS 49

5.1 Hydrologic Analyses 49

5.2 Hydraulic Analyses 62
Volume 2
SECTION 5.0 – ENGINEERING METHODS

5.3 Coastal Analyses 98

5.3.1 Total Stillwater Elevations 99

5.3.2 Waves 101

5.3.3 Coastal Erosion 102

5.3.4 Wave Hazard Analyses 102

5.4 Alluvial Fan Analyses 116
SECTION 6.0 – MAPPING METHODS 116
ii

6.1 Vertical and Horizontal Control 116

6.2 Base Map 118

6.3 Floodplain and Floodway Delineation 119

6.4 Coastal Flood Hazard Mapping 158

6.5 FIRM Revisions 161

6.5.1 Letters of Map Amendment 162

6.5.2 Letters of Map Revision Based on Fill 162

6.5.3 Letters of Map Revision 162

6.5.4 Physical Map Revisions 163

6.5.5 Contracted Restudies 163

6.5.6 Community Map History 164
SECTION 7.0 – CONTRACTED STUDIES AND COMMUNITY COORDINATION 165

7.1 Contracted Studies 165

7.2 Community Meetings 176
SECTION 8.0 – ADDITIONAL INFORMATION 179
SECTION 9.0 – BIBLIOGRAPHY AND REFERENCES 180
Figures
Page
Volume 1
Figure 1: FIRM Index 8
Figure 2: FIRM Notes to Users 10
Figure 3: Map Legend for FIRM 13
Figure 4: Floodway Schematic 34
Figure 5: Wave Runup Transect Schematic 37
Figure 6: Coastal Transect Schematic 39
Figure 7: Frequency Discharge-Drainage Area Curves 60
Volume 2
Figure 8: 1% Annual Chance Total Stillwater Elevations for Coastal Areas 100 Figure 9: Transect Location Map 114
Tables
Page
Volume 1
Table 1: Listing of NFIP Jurisdictions 3
Table 2: Flooding Sources Included in this FIS Report 18 Table 3: Flood Zone Designations by Community 40
Table 4: Basin Characteristics 40
Table 5: Principal Flood Problems 42
iii
Table 6: Historic Flooding Elevations 42
Table 7: Non-Levee Flood Protection Measures 43
Table 8: Levees 48
Table 9: Summary of Discharges 51
Table 10: Summary of Non-Coastal Stillwater Elevations 61 Table 11: Stream Gage Information used to Determine Discharges 62 Table 12: Summary of Hydrologic and Hydraulic Analyses 63 Volume 2
Table 13: Roughness Coefficients 97
Table 14: Summary of Coastal Analyses 99
Table 15: Tide Gage Analysis Specifics 101
Table 16: Coastal Transect Parameters 103
Table 17: Summary of Alluvial Fan Analyses 116
Table 18: Results of Alluvial Fan Analyses 116
Table 19: Countywide Vertical Datum Conversion 117
Table 20: Stream-Based Vertical Datum Conversion 117
Table 21: Base Map Sources 118
Table 22: Summary of Topographic Elevation Data used in Mapping 120 Table 23: Floodway Data 122
Table 24: Flood Hazard and Non-Encroachment Data for Selected Streams 158 Table 25: Summary of Coastal Transect Mapping Considerations 159 Table 26: Incorporated Letters of Map Change 163
Table 27: Community Map History 165
Table 28: Summary of Contracted Studies Included in this FIS Report 166 Table 29: Community Meetings 177
Table 30: Map Repositories 179
Table 31: Additional Information 180
Table 32: Bibliography and References 181
Volume 3
Exhibits
Flood Profiles Panel
Arroyo Grande Creek 01 – 06 P
Atascadero Creek 07 – 10 P
Carpenter Canyon Creek 11 P
Cayucos Creek 12 P
Chorro Creek 13 P
Corbett Canyon Creek 14 – 15 P
Deleissigues Creek 16 – 17 P
East Branch Huerhuero Creek 18 – 20 P
Graves Creek 21 – 26 P
Little Cayucos Creek 27 P
Little Morro Creek 28 – 29 P
Los Berros Creek 30 – 33 P
Meadow Creek 34 – 37 P
iv
Flood Profiles Panel
Middle Branch Huerhuero Creek 38 – 42 P
Miller Overland Flow 43 P
Morro Creek 44 – 46 P
Mountain Springs Creek 47 – 48 P
Nipomo Creek 49 – 52 P
Noname Creek 53 – 54 P
North Fork Los Berros Creek 55 P
North Fork Paloma Creek 56 P
Old Garden Creek 57 – 58 P
Paloma Creek 59 – 61 P
Peachy Canyon Creek 62 P
Pismo Creek 63 P
Prefumo Canyon Creek 64 P
Prefumo Creek 65 – 66 P
Volume 4
Exhibits
Flood Profiles Panel
67 – 72 P
73 – 81 P
82 – 92 P
93 – 98 P
99 P
100 P
101 – 104 P
105 – 107 P
108 P
109 P
110 P
111 P
112 – 113 P
114 – 116 P
117 P
118 – 119 P
120 P
121 – 124 P
125 – 126 P
127 – 131 P
132 P
Salinas River Reach 1
Salinas River
San Luis Obispo Creek South
San Luis Obispo Creek
San Luis Obispo Creek Overflow
San Luis Obispo Creek Splitflow
Santa Margarita Creek
Santa Rosa Creek
Santa Rosa Creek Split Flow
See Canyon Creek
South Branch Toad Creek
South Branch Unnamed Creek No.
1 Stenner Creek
Tefft Road Tributary
Tefft Road Tributary East Fork
Toad Creek (Main and North
Branch)
Toro Creek
Unnamed Creek No. 1
Unnamed Creek (Alva Paul Creek)
Upper Huerhuero Creek
Willow Creek
Yerba Buena Creek 133 P
v
Published Separately
Flood Insurance Rate Map (FIRM)
97 Table 13: Roughness Coefficients
Flooding Source Channel “n” Overbank “n”
Arroyo Grande Creek 0.025 - 0.100 0.030 - 0.120
Atascadero Creek 0.030 - 0.060 0.030 - 0.070
Bradley Canyon 0.048 0.075
Canyon Creek No. 1 0.035 0.055
Canyon Creek No. 2 0.035 0.055
Carpenter Canyon Creek 0.025 - 0.100 0.030 - 0.120
Cayucos Creek 0.030 - 0.060 0.020 - 0.070
Chorro Creek 0.015 - 0.040 0.045 - 0.100
Corbett Canyon Creek 0.025 - 0.100 0.030 - 0.120
Davenport Creek 0.035 0.055
Davis Canyon Creek 0.035 0.055
Deleissigues Creek 0.030-0.070 0.100
Dry Creek 0.035 0.055
East Branch Huerhuero Creek 0.020 - 0.093 0.020 - 2.000 East Branch Huerhuero Creek 0.035 0.055
East Branch San Luis Obispo Creek 0.035 0.055
East Fork Meadow Creek 0.035 0.055
Froom Creek 0.035 0.055
Graves Creek 0.030 - 0.050 0.030 - 0.050
Harford Canyon Creek 0.035 0.055
Huerhuero Creek 0.035 0.055
Little Cayucos Creek 0.040 - 0.070 0.060 - 0.090
Little Morro Creek 0.020 - 0.090 0.100
Los Berros Creek 0.025 - 0.100 0.030 -0.120
Meadow Creek 0.030 - 0.100 0.020 - 2.000
Middle Branch Huerhuero Creek 0.020 - 0.093 0.020 - 2.000 Middle Branch Huerhuero Creek 0.035 0.055
Morro Creek 0.015 - 0.080 0.045 - 0.100
Mountain Springs Creek 0.030 - 0.050 0.030 - 0.040
Nipomo Creek 0.030 - 0.070 0.100
Noname Creek 0.015 - 0.040 0.045 - 0.100
North Fork Los Berros Creek 0.025 - 0.100 0.030 - 0.120 North Fork Paloma Creek 0.030 - 0.050 0.040 - 0.050
Paloma Creek 0.020 - 0.040 0.030 - 0.050
Peachy Canyon Creek 0.024 - 0.050 0.025 - 0.050
Pismo Creek 0.025 - 0.010 0.030 - 0.100
Pismo Creek 0.035 0.055
Pismo Lake Tributary 0.035 0.055
Prefumo Creek, Downstream of
Laguna Lake 0.030 - 0.035 0.035 - 0.080
Prefumo Creek, Upstream of Laguna
Lake 0.060 0.060 - 0.100
Salinas River 0.050 - 0.060 0.060 - 0.070
Table 13: Roughness Coefficients (continued)
98 Flooding Source Channel “n” Overbank “n”
Salinas River Reach 1 0.020 - 0.100 0.021 - 0.100
San Luis Obispo Creek 0.035 - 0.12 0.03 - 0.12
San Luis Obispo Creek South 0.030 - 0.065 0.035 - 0.065 San Marcos Creek 0.035 0.055
Santa Margarita Creek 0.030 - 0.050 0.030 - 0.080
Santa Rosa Creek 0.048 0.016 - 0.100
Santa Rosa Creek Split Flow 0.050 0.100 - 0.200
See Canyon Creek 0.040 0.020 - 0.050
See Canyon Creek (Lower Reach) 0.035 0.055
See Canyon Creek (Upper Reach) 0.035 0.055
South Branch Toad Creek 0.040 0.016 - 0.100
South Branch Unnamed Creek No. 1 0.015 - 0.050 0.030 - 0.050 Stenner Creek 0.065 0.040 - 0.070
Tank Farm Creek 0.035 0.055
Tefft Road Tributary 0.250 0.250
Tefft Road Tributary East Fork 0.070 0.100
Toad Creek (Main and North
Branches) 0.020 - 0.050 0.030 - 0.060
Toro Creek 0.015 - 0.040 0.045 - 0.100
Unnamed Creek (Alva Paul Creek) 0.015 - 0.040 0.045 - 0.100 Unnamed Creek No. 1 0.015 - 0.050 0.030 - 0.050
Unnamed Stream HU-01 0.035 0.055
Unnamed Stream HU-02 0.035 0.055
Unnamed Stream HU-03 0.035 0.055
Unnamed Stream HU-04 0.035 0.055
Unnamed Stream HU-05 0.035 0.055
Unnamed Stream HU-06 0.035 0.055
Unnamed Stream SO-03 0.035 0.055
Upper Branch Huerhuero Creek 0.020 - 0.093 0.020 - 2.000 Vineyard Canyon Creek 0.035 0.055
Willow Creek 0.030 - 0.070 0.030 - 0.070
Yerba Buena Creek 0.030 - 0.050 0.020 - 0.080

5.3 Coastal Analyses
For the areas of San Luis Obispo 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 14 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.
99 Table 14: Summary of Coastal Analyses
Flooding
Source
Study Limits
From
Study Limits
To
Hazard
Evaluated
Model or
Method
Used
Date Analysis
was
Completed
Pacific
Ocean
Southern
Monterey
County
Border
Northern
Santa
Barbara
County
Border
Runup
WHAFIS
FEMA
Pacific
Guidelin
es
(2005).

Stockdon,
DIM, and
TAW used
to evaluate
Runup
12/30/2014

5.3.1 Total Stillwater Elevations
The total stillwater elevations (stillwater including storm surge plus wave setup) for the 1- percent-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 14. The stillwater elevation that was used for each transect in coastal analyses is shown in Table 16, “Coastal Transect Parameters.” Figure 8 shows the total stillwater elevations for the 1-percent-annual-chance flood that was determined for this coastal analysis.
100
Figure 8: 1% Annual Chance Total Stillwater Elevations for Coastal Areas Astronomical Tide
Astronomical tidal statistics were generated directly from local tidal constituents by sampling the predicted tide at random times throughout the tidal epoch.

Storm Surge Statistics
Storm surge is modeled based on characteristics of actual storms responsible for significant coastal flooding. The characteristics of these storms are typically determined by statistical study of the regional historical record of storms or by statistical study of tidal gages.

When historic records are used to calculate storm surge, characteristics such as the strength, size, track, etc., of storms are identified by site. Storm data was used in conjunction with numerical hydrodynamic models to determine the corresponding storm surge levels. An extreme value analysis was performed on the storm surge modeling results to determine a stillwater elevation for the 1-percent-annual-chance event. 101
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 storm surge component. Table 15 provides the gage name, managing agency, gage type, gage identifier, start date, end date, and statistical methodology applied to each gage used to determine the stillwater elevations. For areas between gages, peak stillwater elevations for selected recurrence intervals were estimated by combining interpolation between gages and observed high water marks during major storms. A regionalized statistical approach was applied to the gage data so that stillwater elevations in areas between gages could be identified.

Table 15: Tide Gage Analysis Specifics
Gage Name
Managing
Agency of
Tide Gage
Record Gage Type Start Date End Date
Statistical
Methodology
Port San
Luis
(9412110)
NOAA Tide 05/31/1945 04/14/2011 GEV
Combined Riverine and Tidal Effects
This section is ot applicable to this Flood Risk Project.

Wave Setup Analysis
Wave setup was computed during the storm surge modeling through the methods and models listed in Table 14 and included in the frequency analysis for the determination of the total stillwater elevations.

5.3.2 Waves
An integral component of the transect-based TWL analysis is an accurate determination of the offshore and nearshore wave climate. A continuous 50- year hourly deep-water wave hindcast was developed by Oceanweather Inc using reanalysis of historical wind fields. Three nested model grid components of sequentially higher resolution were used to resolve wave conditions of varying spatial scales, including basin (global), regional (Northeast Pacific Ocean), and coastal (California) grids.

The deep-water dataset was further transformed to reflect nearshore conditions at the edge of the surf zone in approximately 33-49 feet water depth. The nearshore wave transformation component was carried out by the Scripps Institute of Oceanography (SIO) Coastal Data Information Program (CDIP) research group in collaboration with BakerAECOM using the SIO SHELF model. The output from this wave transformation model provides the input conditions for the 1-D transect-based coastal hazard analysis used to calculate BFEs.
102

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 14. 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- percent-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 16 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 14, “Summary of Coastal Analyses”. For the 0.2-percent-annual-chance event, wave profiles were created to indicate the results of the wave height analysis at each transect. Such wave profiles may show greater detail than the mapping product, due to limitations of the map scale and smoothing tolerances applied during boundary cleanup. Wave runup analysis for the 0.2-percent-annual-chance event was not performed for this study and is not included in the profiles.

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-percent-annual-chance flood. Wave runup elevations were modeled using the methods and models listed in Table 14. 103 Table 16: Coastal Transect Parameters Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 107597.70 3968584.17 17.9 20.7 22.0 25.4 108264.75 3966493.04 17.3 18.9 19.5 21.1 108481.74 3963784.35 19.3 21.6 22.7 25.8 108827.74 3961592.56 14.5 15.7 16.1 17.3 109157.62 3960146.10 14.0 15.9 16.7 18.8 110453.02 3957863.40 15.0 19.1 21.6 29.3 110618.10 3957701.94 29.6 35.4 37.7 42.9 Table 16: Coastal Transect Parameters (continued) 104 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 111406.39 3955775.11 19.4 20.8 21.4 22.6 115231.24 3953168.02 19.6 26.9 31.1 44.5 116581.38 3952280.83 14.7 18.0 19.8 25.2 117233.38 3951906.80 15.5 16.9 17.6 19.1 118845.89 3951282.83 30.9 35.2 37.0 41.2 120508.76 3950828.22 14.8 16.4 17.1 18.7 120671.59 3950799.03 15.1 16.5 17.0 18.2 121009.02 3950739.14 16.0 19.2 21.1 27.0 Table 16: Coastal Transect Parameters (continued) 105 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 16 121318.70 3950679.41 13.6 14.8 15.4 16.6 17 122784.66 3950045.32 28.1 34.3 37.2 44.2 18 123957.48 3948465.85 15.9 18.3 19.6 23.2 19 124800.76 3946727.87 15.3 20.8 24.5* 37.6 20 125012.87 3946288.26 16.2 18.0 18.8 20.8 21 125225.85 3945766.71 17.2 19.0 19.9 22.0 22 126018.27 3944135.05 16.0 17.6 18.4 20.4 23 126627.90 3943321.25 17.1 18.8 19.6 21.5 Table 16: Coastal Transect Parameters (continued) 106 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 24 127137.36 3942514.42 22.0 26.6 28.7 33.8 25 127632.44 3941567.44 16.0 21.1 24.4 36.2 26 128101.97 3940620.42 13.8 16.3 17.8 23.0 27 132469.61 3934923.28 19.6 22.0 23.2 26.3 28 137543.97 3930574.65 16.5 18.2 18.9 20.7 29 139854.02 3929349.37 20.0 25.4 28.7 39.4 30 142800.77 3928600.26 19.1 23.6 25.6 30.7 31 144824.25 3928722.73 18.5 22.2 24.1 29.2 Table 16: Coastal Transect Parameters (continued) 107 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 32 144876.60 3928703.00 13.1 14.1 14.6* 15.5 33 144899.47 3928693.56 13.1 14.3 14.8 16.1 34 145088.15 3928597.27 14.7 16.7 17.8* 20.8 35 145497.36 3928248.45 16.7 18.2 18.8 20.2 36 146164.73 3927113.48 14.0 16.2 17.3 20.5 37 146444.79 3926457.76 14.0 16.8 18.4 23.5 38 147026.60 3925417.45 14.8 16.3 16.9 18.5 39 147587.19 3924358.29 14.7 17.3 18.7 23.0 Table 16: Coastal Transect Parameters (continued) 108 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 40 147676.28 3924138.58 13.0 13.8 14.2 14.9 41 147895.86 3923422.60 12.7 14.1 14.8 16.7 42 148148.07 3921478.72 14.1 15.1 15.6 16.6 43 147857.59 3918184.81 19.4 20.9 21.5 22.9 44 147304.66 3915738.59 23.3 25.1 25.9 27.5 45 146632.36 3913939.98 20.2 21.8 22.6 24.2 46 146060.59 3912736.01 14.1 15.8 16.6 18.5 47 145330.40 3911011.16 23.3 25.5 26.5* 28.8 Table 16: Coastal Transect Parameters (continued) 109 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 48 144750.71 3908695.56 16.9 20.2 21.7 25.8 49 146617.25 3904707.98 18.7 21.5 22.9 26.9 50 148152.83 3903031.90 32.3 37.2 39.3 44.3 51 148857.97 3902488.58 18.0 21.4 22.4 23.8 52 153585.46 3898489.00 15.8 18.3 19.5* 22.4 53 158966.50 3897559.64 9.4 10.2 10.5* 11.2 54 159060.30 3897852.61 21.4 25.8 28.1 34.3 55 159111.16 3897880.68 11.9 13.1 13.7 15.3 Table 16: Coastal Transect Parameters (continued) 110 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 56 159122.75 3897881.35 15.9 20.1 22.4 28.9 57 159430.71 3897873.59 13.1 14.4 15.1 16.7 58 159640.30 3897850.56 14.3 15.8 16.5* 18.2 59 159782.25 3897826.63 14.0 16.0 17.0 19.7 60 160929.03 3897366.61 29.5 32.0 33.0 35.1 61 161666.90 3896876.01 22.4 24.2 25.0 26.5 62 162449.65 3896309.31 16.9 18.2 18.8 20.1 63 163543.69 3895431.75 13.1 16.1 17.9 23.4 Table 16: Coastal Transect Parameters (continued) 111 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 64 163772.33 3895256.99 12.9 15.4 16.9 21.2 65 165935.26 3894674.64 23.8 26.1 27.2 29.6 66 166054.02 3894597.46 18.3 20.5 21.4 23.3 67 166422.49 3894308.22 12.4 13.6 14.1 15.5 68 166618.01 3894122.24 12.2 13.1 13.5 14.6 69 166795.66 3893931.32 14.0 17.1 19.0 25.3 70 166914.14 3893790.86 12.9 14.1 14.7 16.1 71 166999.95 3893681.64 12.3 13.2 13.7 14.8 Table 16: Coastal Transect Parameters (continued) 112 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 72 167572.10 3892597.22 13.5 14.7 15.2 16.5 73 167792.62 3891579.05 13.1 14.1 14.5* 15.4 74 167953.88 3890288.16 13.7 14.9 15.4 16.6 75 167951.18 3888905.74 14.3 15.4 15.9 17.1 76 167847.98 3886987.21 13.5 14.3 14.6 15.2 77 167546.01 3884353.76 22.3 24.5 25.5* 27.7 78 167385.20 3883333.58 20.8 22.7 23.5* 25.3 79 166352.97 3878838.95 17.4 19.1 19.8 21.5 Table 16: Coastal Transect Parameters (continued) 113 Transect X,Y Coordinates (Meters, NAD83 UTM Zone 11N) Total Water Level (feet NAVD88)1 10% Annual Chance 2% Annual Chance 1% Annual Chance 0.2% Annual Chance 80 150416.84 3918291.35 --1 --1 12.2 --1 812,3 151493.19 3917425.72 --1 --1 9.5 --1 82 150588.04 3916765.21 --1 --1 12.3 --1 832,4 150340.83 3915525.93 --1 --1 9.8 --1 1North American Vertical Datum of 1988 *Value has been rounded to the nearest tenth of a foot – precision of results to the hundredths of a foot resulted in rounding the BFE on the FIRM down to the nearest whole foot due to the analysis precision. 1Data not calculated for this Flood Risk Project 2Transects were mapped using wave height analysis. Static Wave setup was less than half a foot and 1% SWEL is 7.8 feet. 31% wave crest elevation of 9.5 feet. 41% wave crest elevation of 9.8 feet. (18
(2
(
(
(8
(
(
(4
(
(24
(21
(
(
(28
(
(6
(
(14
(
(11
(5
(23
(
(7
(12
(20
(15
(
(13
(
Shoreline
Nacimiento Reservoir
Villa Creek
Perry Creek
Arroyo De
La Cruz
Las Tablas Creek
San Simeon Creek
Green Valley Creek
Pico Creek
Santa Rosa Creek
San Carpoforo Creek
Nacimiento River

NATIONAL FLOOD INSURANCE PROGRAM
Transect Locator Map
SAN LUIS OBISPO COUNTY, CALIFORNIA and Incorporated Areas PANELS WITH TRANSECTS FEMA 0012, 0014, 0252, 0254, 0258, 0266, 0288, 0289, 0293, 0506, 0507, 0509, 0528, 0536, 0756, 0778, 0779, 0783, 0784, 0792, 0811, 0813, 1017, 1019, 1026, 1028, 1029, 1036, 1282, 1301, 1303, 1316, 1317, 1336, 1337, 1339, 1341, 1343, 1344, 1582, 1584, 1592, 1857 COUNTY LOCATOR 0 6,500 13,000 26,000
feet Map Projection: North American Datum 1983
1 inch = 13,333 feet 1:160,000
Figure 9: Transect Location Map
11 (
(44
(42
(
(74
(72
(81
(50
(43
(76
(
(45
!(
(
(
(77
(53
(
(
( ( !(
!(
(
(80
(
(39
(40
(
(48
(73
(75
(33
(46
(32
(71
(31
(59
(70
(58
(38
(57
(56
!(
(35
!(78
(64
(36
(
(69
68 (
(
(
Shoreline
Willow Creek
Noname Creek
Santa Margarita Creek
Cayucos
Creek
Toro Creek
Unnamed
Creek
(Alva
Paul
Creek)
Middle Branch
Huerhuero Creek
Black Lake
Canyon Creek
Brizziolari Creek
North Fork Paloma Creek
Davis Canyon Creek
Little Morro Creek
Santa Maria River
Prefumo Creek
Paloma Creek
San Luis Obispo Creek
Chorro Creek
San Luisito Creek
Pismo Creek
Morro Creek
San Bernardo Creek
Islay Creek
Los Berros Creek
San Luis Obispo
Creek South
Salinas River
Stenner Creek
Arroyo
Grande
Creek
Los Osos Creek
Rogers Creek
Yerba Buena Creek
Oso Flaco Creek
Trout Creek
Pilitas
Creek
Whale Rock Reservoir
Atascadero Creek
Meadow
Creek
Graves Creek
Canyon Creek
Number 2
Old Garden Creek
Froom Creek
East Fork
Meadow
Creek
East Branch
Huerhuero Creek
Santa
Margarita
Lake
Canyon Creek
Number 1
Hazard Canyon Creek
See Canyon Creek
(Lower Reach)
See Canyon Creek
(Upper Reach)
Davenport Creek
Corbett
Canyon
Creek

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

Table 17: Summary of Alluvial Fan Analyses
[Not Applicable to this Flood Risk Project]
Table 18: Results of Alluvial Fan Analyses
[Not Applicable to this Flood Risk Project]
SECTION 6.0 – MAPPING METHODS

6.1 Vertical and Horizontal Control
All FIS Reports and FIRMs are referenced to a specific vertical datum. The vertical datum provides a starting point against which flood, ground, and structure elevations can be referenced and compared. Until recently, the standard vertical datum used for newly created or revised FIS Reports and FIRMs was the National Geodetic Vertical Datum of 1929 (NGVD29). With the completion of the North American Vertical Datum of 1988 (NAVD88), many FIS Reports and FIRMs are now prepared using NAVD88 as the referenced vertical datum.

Flood elevations shown in this FIS Report and on the FIRMs are referenced to NAVD88, with the exception of 10 panels: 06079C1619F, 06079C1638F, 06079C1639F, 06079C1880F, 06079C1885F, 06079C1902F, 06079C1905F, 06079C1906F, 06079C1910F and 06079C1950F. These panels were not updated with the November 16, 2012 revision and are referenced to NGVD 29. Flooding sources on the non-updated FIRMS include Nipomo Creek and Santa Maria River. Profile 43P is a duplicate of profile 40P provided in NGVD 29 for use only with effective panels 06079C1639F, 06079C1902F, and 06079C1906F. Due to the fact that base flood elevations along Nipomo Creek are depicted on panel 06079C1643G in NAVD 88 and on panels 06079C1639F, 06079C1902F, and 06079C1906F in NGVD 29, differences in base flood elevations may result across panel edges.

These flood elevations must be compared to structure and ground elevations referenced to the same vertical datum. For information regarding conversion between NGVD29 and NAVD88 or other datum conversion, visit the National Geodetic Survey website at www.ngs.noaa.gov. Temporary vertical monuments are often established during the preparation of a flood hazard analysis for the purpose of establishing local vertical control. Although these monuments are not shown on the FIRM, they may be found in the archived project documentation associated with the FIS Report and the FIRMs for this community.

Interested individuals may contact FEMA to access these data.

To obtain current elevation, description, and/or location information for benchmarks in the 117
area, please visit the NGS website at www.ngs.noaa.gov. The datum conversion locations and values that were calculated for San Luis Obispo County are provided in Table 19.

Table 19: Countywide Vertical Datum Conversion
[Not Applicable to this Flood Risk Project]
A countywide conversion factor could not be generated for San Luis Obispo County because the maximum variance from average exceeds 0.25 feet. Calculations for the vertical offsets on a stream by stream basis are depicted in Table 20.

Table 20: Stream-Based Vertical Datum Conversion
Flooding Source
Average Vertical Datum
Conversion Factor (feet)
Arroyo Grande Creek 2.82
Atascadero Creek 3.15
Carpenter Canyon Creek 2.84
Cayucos Creek 2.76
Chorro Creek 2.79
Corbett Canyon Creek 2.84
Deleissigues Creek 2.77
Graves Creek 3.13
Little Cayucos Creek 2.76
Little Morro Creek 2.80
Los Berros Creek 2.82
Morro Creek 2.80
Mountain Springs Creek 3.13
Nipomo Creek 2.73
Noname Creek 2.78
North Fork Los Berros Creek 2.83
North Fork Paloma Creek 3.15
Old Garden Creek 2.86
Peachy Canyon Creek 3.16
Prefumo Canyon Creek 2.87
Prefumo Creek 2.87
Pismo Creek 2.86
Salinas River 3.15
San Luis Obispo Creek 2.89
Santa Margarita Creek 3.07
Santa Rosa Creek 2.73
Santa Rosa Creek Split Flow 2.71
See Canyon Creek 2.92
South Branch Toad Creek 3.12
South Branch Unnamed Creek No. 1 3.17
Stenner Creek 2.86
Tefft Road Tributary 2.77
Table 20: Stream-Based Vertical Datum Conversions (continued) 118
Flooding Source
Average Vertical Datum
Conversion Factor (feet)
Tefft Road Tributary East Fork 2.78
Toad Creek 3.14
Toro Creek 2.77
Unnamed Creek (Alva Paul Creek) 2.78
Unnamed Creek No. 1 3.15
Willow Creek 2.78
Yerba Buena Creek 2.96
Static Elevation Along Arroyo Grande Creek 2.82
Static Elevation Along Paloma Creek 3.17
Static Elevation Along Salinas River 3.12
Static Elevation Along Santa Margarita Creek 3.05
Static Elevation Along Toad Creek 3.12
Static Elevation At Laguna Lake 2.86
Static Elevation At Morro Bay 2.86
Static Elevation At Pacific Ocean 2.80

6.2 Base Map
The FIRMs and FIS Report for this project have been produced in a digital format. The flood hazard information was converted to a Geographic Information System (GIS) format that meets FEMA’s FIRM Database specifications and geographic information standards.

This information is provided in a digital format so that it can be incorporated into a local GIS and be accessed more easily by the community. The FIRM Database includes most of the tabular information contained in the FIS Report in such a way that the data can be associated with pertinent spatial features. For example, the information contained in the Floodway Data table and Flood Profiles can be linked to the cross sections that are shown on the FIRMs. Additional information about the FIRM Database and its contents can be found in FEMA’s Guidelines and Standards for Flood Risk Analysis and Mapping, www.fema.gov/media-library/resources-documents/collections/361. Base map information shown on the FIRM was derived from the sources described in Table 21.

Table 21: Base Map Sources
Data Type Data Provider
Data
Date
Data
Scale Data Description
Administrative
Forest
USDA Forest
Service 2020 National Forest Boundaries
BOE City
Boundaries
County of San
Luis Obispo GIS 2015 City Boundaries of San Luis Obispo CA California State
Parks System
California
Department of
Parks and
Recreation
2018 1:24,000 State Park Boundaries
Table 21: Base Map Sources (continued)
119
Data Type Data Provider
Data
Date
Data
Scale Data Description
Coastal California
Digital Imagery
Coastal Services
Center 2011 1:24,000 Coastal California Digital Imagery Coastal California
LiDAR and Digital
Imagery
Coastal Services
Center 2011 1:24,000 Coastal California LiDAR and Digital Imagery County Boundary County of San
Luis Obispo GIS 2020 County Boundary of San Luis Obispo CA County of San Luis
Obispo
Transportation Lines
County of San
Luis Obispo GIS 2017 1:24,000 Transportation Lines for San Luis Obispo County National Agriculture
Imagery Program
United States
Department of
Agriculture Farm
Service Agency
2016 1:24,000 Basemap Imagery Index
National Agriculture
Imagery Program
U.S. Department
of Agriculture
Farm Service
Agency
2005 1:12,000
Location of roads, railroads,
bridges, streams, general
structures, and other physical
features.

National
Hydrography
Dataset
United States
Geological
Survey
2018 1:24,000 National Hydrology used for Water
Line feature
NOAA Tides and
Currents NOAA 2015 1:24,000 Coastal Gage Location
San Luis Obispo
County PLSS data,
State and Federal
land boundaries
California Spatial
Information
Library
1993 1:100,000 Public Land Survey System (range,
township, and sections)
TIGER/Line Files
Transportation
Layer
U.S. Department
of Commerce,
U.S. Census
Bureau,
Geography
Division
2013 1:24,000 Spatial and attribute information for
Transportation

USDA-FSA-APFO
NAIP MrSID Mosaic
US Department
of Agriculture
Farm Service
Agency Aerial
Photography
Field Office
2012 1:40,000 Countywide Digital Ortho Mosaic

6.3 Floodplain and Floodway Delineation
The FIRM shows tints, screens, and symbols to indicate floodplains and floodways as well as the locations of selected cross sections used in the hydraulic analyses and floodway computations.

For riverine flooding sources, the mapped floodplain boundaries shown on the FIRM have 120
been delineated using the flood elevations determined at each cross section; between cross sections, the boundaries were interpolated using the topographic elevation data described in Table 22. For each coastal flooding source studied as part of this FIS Report, the mapped floodplain boundaries on the FIRM have been delineated using the flood and wave elevations determined at each transect; between transects, boundaries were delineated using land use and land cover data, the topographic elevation data described in Table 22, and knowledge of coastal flood processes. In ponding areas, flood elevations were determined at each junction of the model; between junctions, boundaries were interpolated using the topographic elevation data described in Table 22.

In cases where the 1-percent and 0.2-percent-annual-chance floodplain boundaries are close together, only the 1-percent-annual-chance floodplain boundary has been shown.

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 data.

The floodway widths presented in this FIS Report and on the FIRM were computed for certain stream segments on the basis of equal conveyance reduction from each side of the floodplain. Floodway widths were computed at cross sections. Between cross sections, the floodway boundaries were interpolated. Table 2 indicates the flooding sources for which floodways have been determined. The results of the floodway computations for those flooding sources have been tabulated for selected cross sections and are shown in Table 23, “Floodway Data.”
Certain flooding sources may have been studied that do not have published BFEs on the FIRMs, or for which there is a need to report the 1-percent-annual-chance flood elevations at selected cross sections because a published Flood Profile does not exist in this FIS Report. These streams may have also been studied using methods to determine nonencroachment zones rather than floodways. For these flooding sources, the 1-percentannual-chance floodplain boundaries have been delineated using the flood elevations determined at each cross section; between cross sections, the boundaries were interpolated using the topographic elevation data described in Table 22. All topographic data used for modeling or mapping has been converted as necessary to NAVD88. The 1- percent-annual-chance elevations for selected cross sections along these flooding sources, along with their non-encroachment widths, if calculated, are shown in Table 23, “Flood Hazard and Non-Encroachment Data for Selected Streams.” Table 22: Summary of Topographic Elevation Data used in Mapping Community
Flooding
Source
Source for Topographic Elevation Data
Description
Vertical
Accuracy
Horizontal
Accuracy Citation
San Luis Obispo
County
Pacific
Ocean
Coastal California LiDAR
and Digital Imagery N/A 2 ft N/A
San Luis Obispo
County
Various
Sources
U.S. Department of
Agriculture Farm
Service Agency

N/A N/A N/A
Table 22: Summary of Topographic Elevation Data used in Mapping (continued) 121
Community
Flooding
Source
Source for Topographic Elevation Data
Description
Vertical
Accuracy
Horizontal
Accuracy Citation
San Luis Obispo
County
Cuyama
River, Oso
Flaco
Creek,
Santa
Maria
River, and
Suey
Creek
Digital Orthophoto
Quadrangles 1:12,000 N/A N/A
BFEs shown at cross sections on the FIRM represent the 1-percent-annual-chance water surface 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. 122 Table 23: Floodway Data LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE A-H* 14,599 1,204 13.1 61.3 61.3 61.3 0.0 15,000 1,611 6.5 64.2 64.2 64.2 0.0 15,470 1,853 5.7 68.0 68.0 68.7 0.7 15,803 1,674 6.3 69.8 69.8 70.3 0.5 16,474 1,747 6.0 73.0 73.0 73.4 0.4 17,794 1,286 8.2 78.3 78.3 78.9 0.6 18,480 1,859 5.6 82.5 82.5 82.9 0.4 19,013 1,446 7.3 84.2 84.2 84.4 0.2 19,800 1,183 8.9 89.3 89.3 89.3 0.0 20,830 2,128 4.9 93.6 93.6 93.6 0.0 24,204 1,286 8.2 115.3 115.3 115.3 0.0 24,816 854 12.3 119.9 119.9 119.9 0.0 26,083 1,490 7.0 128.8 128.8 129.4 0.6 27,657 1,358 7.7 133.7 133.7 134.6 0.9 29,325 883 11.9 145.6 145.6 145.6 0.0 30,371 1,623 6.5 149.0 149.0 149.6 0.6 31,442 1,703 6.2 152.9 152.9 153.3 0.4 33,026 1,590 6.6 160.5 160.5 160.7 0.2 AA 34,162 1,579 6.7 166.6 166.6 166.9 0.3 AB 35,772 2,173 4.8 173.4 173.4 173.7 0.3 AC 37,752 1,558 5.6 198.0 198.0 198.0 0.0 1Feet above Pacific Ocean *Data not available TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: ARROYO GRANDE CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 123 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 1,168 985 6.8 827.5 827.5 827.6 0.1 1,625 1,514 4.4 829.2 829.2 829.3 0.1 2,158 1,270 5.3 829.7 829.7 829.8 0.1 2,682 669 10.0 834.5 834.5 834.5 0.0 3,832 705 9.4 839.1 839.1 839.1 0.0 4,728 1,226 5.4 842.2 842.2 842.2 0.0 5,325 625 10.6 845.4 845.4 845.4 0.0 6,265 1,035 6.4 852.8 852.8 852.8 0.0 7,081 1,162 5.6 854.2 854.2 854.2 0.0 7,544 1,397 4.6 856.3 856.3 856.4 0.1 8,224 1,538 4.2 864.3 864.3 864.3 0.0 9,091 589 10.8 870.1 870.1 870.1 0.0 10,348 709 9.0 877.9 877.9 878.1 0.2 11,133 581 10.7 880.4 880.4 881.4 1.0 12,117 846 7.5 891.9 891.9 891.9 0.0 13,199 656 9.6 896.4 896.4 896.4 0.0 14,384 891 7.1 902.8 902.8 903.0 0.2 15,213 911 6.8 907.3 907.3 907.3 0.0 16,214 1,645 3.7 908.3 908.3 909.1 0.8 17,124 1,238 4.9 909.3 909.3 909.9 0.6 18,023 1,363 4.3 916.1 916.1 916.1 0.0 19,067 1,433 4.1 916.4 916.4 916.4 0.0 1Feet above confluence with Salinas River TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: ATASCADERO CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 124 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 290 30 111 5.4 163.8 163.8 164.8 1.0 407 30 69 8.7 165.6 165.6 165.6 0.0 528 90 99 6.1 168.9 168.9 168.9 0.0 1Feet above confluence with Corbett Canyon Creek TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: CARPENTER CANYON CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 125 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 438 581 12.1 12.9 12.9 12.9 0.0 671 858 8.2 14.8 14.8 14.8 0.0 898 1,346 5.2 15.9 15.9 16.6 0.7 1,082 1,348 5.2 16.2 16.2 17.0 0.8 1,309 1,009 6.9 16.7 16.7 17.2 0.5 1,542 960 7.3 17.9 17.9 18.6 0.7 1,758 1,113 6.3 19.0 19.0 19.7 0.7 2,107 1,653 4.2 20.4 20.4 21.0 0.6 2,413 1,025 6.8 20.8 20.8 21.4 0.6 2,598 1,488 4.7 24.0 24.0 24.7 0.7 2,904 982 7.1 24.2 24.2 24.8 0.6 1Feet above Pacific Ocean TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: CAYUCOS CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 126 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 348 2,961 0.9 122.5 122.5 123.5 1.0 544 2,481 1.0 122.5 122.5 123.5 1.0 834 973 2.7 122.5 122.5 123.5 1.0 1,024 1,013 2.6 122.6 122.6 123.6 1.0 1,225 1,634 1.6 122.9 122.9 123.9 1.0 1,563 1,333 2.0 123.3 123.3 124.3 1.0 1,922 438 9.4 124.3 124.3 125.0 0.7 2,123 512 6.8 127.0 127.0 127.7 0.7 2,724 837 4.9 131.9 131.9 132.9 1.0 3,564 456 5.7 137.1 137.1 137.7 0.6 3,865 268 9.0 139.8 139.8 140.0 0.2 4,166 962 3.6 144.4 144.4 145.3 0.9 4,404 762 3.4 145.8 145.8 146.0 0.2 5,074 298 9.3 151.9 151.9 152.5 0.6 5,618 204 11.3 157.5 157.5 157.8 0.3 6,146 252 9.1 162.9 162.9 163.4 0.5 6,574 271 8.5 169.3 169.3 170.3 0.9 1Feet above confluence with Arroyo Grande Creek TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: CORBETT CANYON CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 127 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 1,056 155 8.4 315.0 315.0 315.0 0.0 1,320 264 4.9 319.3 319.3 319.4 0.1 1,980 192 6.8 325.1 325.1 325.1 0.0 2,820 365 3.6 334.5 334.5 334.9 0.4 3,823 166 7.8 339.8 339.8 339.8 0.0 4,208 316 4.1 344.8 344.8 344.8 0.0 4,404 162 8.0 347.4 347.4 347.4 0.0 4,504 148 8.8 348.4 348.4 348.4 0.0 5,095 681 1.9 354.3 354.3 354.7 0.4 1Feet above confluence with Nipomo Creek TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: DELEISSIGUES CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 128 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 626 714 8.6 774.1 774.1 774.2 0.1 936 747 8.3 776.4 776.4 776.4 0.0 1,351 727 8.5 777.5 777.5 777.5 0.0 1,482 539 11.2 777.8 777.8 777.8 0.0 2,198 1,027 5.9 781.1 781.1 781.1 0.0 2,315 786 7.7 781.1 781.1 781.1 0.0 3,020 811 7.2 782.6 782.6 782.6 0.0 3,515 439 13.5 783.5 783.5 783.5 0.0 4,527 700 8.5 794.2 794.2 794.2 0.0 4,835 857 6.9 795.3 795.3 795.3 0.0 5,954 548 10.5 798.5 798.5 798.5 0.0 6,554 591 9.6 806.5 806.5 806.5 0.0 7,490 745 7.3 809.9 809.9 809.9 0.0 7,667 1,058 5.2 814.4 814.4 814.4 0.0 8,634 602 9.0 815.7 815.7 815.7 0.0 9,242 382 13.4 819.1 819.1 819.1 0.0 9,847 639 8.2 825.6 825.6 825.6 0.0 10,625 380 13.7 830.2 830.2 830.2 0.0 11,175 569 9.2 836.7 836.7 836.7 0.0 12,105 999 5.2 843.3 843.3 843.3 0.0 12,803 522 9.8 844.5 844.5 844.5 0.0 13,193 851 6.3 847.2 847.2 847.2 0.0 13,955 1,307 4.0 848.6 848.6 848.7 0.1 14,440 695 7.1 859.3 859.3 859.3 0.0 14,915 679 6.9 860.9 860.9 861.3 0.4 15,881 978 6.2 862.9 862.9 863.0 0.1 1Feet above confluence with Salinas River TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: GRAVES CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 129 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE AA 16,893 540 8.6 867.1 867.1 867.1 0.0 AB 17,798 398 11.6 875.0 875.0 875.0 0.0 AC 18,228 624 7.4 880.2 880.2 880.2 0.0 AD 18,907 560 8.2 882.7 882.7 882.7 0.0 AE 19,286 416 10.9 885.1 885.1 885.1 0.0 AF 20,071 616 7.0 893.5 893.5 893.5 0.0 AG 21,051 542 7.39 897.7 897.7 897.7 0.0 AH 21,766 353 12.1 904.0 904.0 904.0 0.0 AI 22,098 398 10.9 909.4 909.4 909.4 0.0 AJ 22,753 316 12.5 915.7 915.7 915.7 0.0 AK 22,948 363 10.8 919.0 919.0 919.0 0.0 AL 23,974 511 7.8 925.3 925.3 925.3 0.0 AM 24,742 876 4.5 934.2 934.2 934.2 0.0 AN 25,742 458 8.7 939.3 939.3 939.3 0.0 AO 26,420 633 6.3 947.3 947.3 947.3 0.0 AP 27,477 374 10.5 951.1 951.1 951.1 0.0 AQ 27,848 730 5.1 959.4 959.4 959.4 0.0 AR 28,499 446 7.1 963.9 963.9 963.9 0.0 AS 29,202 530 5.0 967.3 967.3 967.3 0.0 AT 30,391 269 5.8 975.9 975.9 975.9 0.0 AU 31,515 444 6.9 987.7 987.7 987.7 0.0 AV 32,327 352 8.6 994.3 994.3 994.3 0.0 AW 33,052 310 10.0 1,001.5 1,001.5 1,001.5 0.0 AX 34,475 302 10.0 1,017.2 1,017.2 1,017.2 0.0 1Feet above confluence with Salinas River TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: GRAVES CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 130 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 269 47 158 7.3 12.7 12.7 12.7 0.0 401 70 553 2.1 20.6 20.6 21.6 1.0 634 28 223 5.1 20.6 20.6 21.6 1.0 792 47 183 6.3 22.0 22.0 22.2 0.2 1,088 47 233 4.9 25.2 25.2 25.2 0.0 1,373 51 204 5.6 27.1 27.1 27.2 0.0 H2 1,742 61 267 4.3 30.1 30.1 30.2 0.1 I2 1Feet above Pacific Ocean 2Data not available TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: LITTLE CAYUCOS CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 131 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 5,523 249 9.6 82.4 82.4 1.0 6,103 658 3.6 88.1 88.1 0.6 6,494 235 10.2 90.2 90.2 0.1 6,721 338 7.1 95.3 95.3 0.7 7,054 897 2.7 97.8 97.8 0.8 7,424 213 11.3 100.7 100.7 0.6 7,582 837 2.9 106.5 106.5 0.7 7,920 293 8.2 108.0 108.0 0.4 8,078 1,326 1.8 111.3 111.3 0.8 8,459 477 5.0 112.9 112.9 0.3 9,018 830 2.9 118.8 118.8 0.6 9,282 346 6.9 120.3 120.3 0.3 9,689 219 10.9 130.2 130.2 0.1 10,359 756 3.2 138.3 138.3 0.3 1Feet above confluence with Morro Creek TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: LITTLE MORRO CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 132 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 3,062 1,424 7.0 72.5 72.5 73.5 1.0 4,435 3,119 3.2 76.2 76.2 77.0 0.8 6,178 1,899 5.3 87.2 87.2 88.0 0.8 7,286 2,252 4.4 94.5 94.5 95.4 0.9 9,082 1,012 6.0 106.2 106.2 106.4 0.2 9,805 1,198 10.8 111.5 111.5 112.3 0.8 10,291 743 7.7 117.5 117.5 117.5 0.0 11,806 650 8.0 131.0 131.0 131.6 0.6 13,765 652 8.0 149.7 149.7 149.8 0.1 J 15,069 61 411 12.7 164.3 164.3 164.6 0.3 K2 16,753 * * * 185.0 * * * L 18,142 565 9.2 195.5 195.5 195.9 0.4 M 20,096 886 5.7 209.6 209.6 210.0 0.4 N 20,418 571 8.8 212.0 212.0 212.3 0.3 O 21,410 1,047 4.8 221.5 221.5 221.9 0.4 22,139 904 5.5 225.9 225.9 226.9 1.0 24,964 526 9.5 247.7 247.7 248.5 0.8 25,603 * * 258.5 * * * 26,727 * * 262.4 * * * 1Stream distance in feet above confluence with Arroyo Grande Creek 2Floodway not calculated *Data not available TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: LOS BERROS CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 133 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE A 16,798 299 1,053 1.2 22.9 22.9 23.1 0.2 B 17,960 405 566 2.3 27.4 27.4 27.6 0.2 C 18,495 73 252 5.2 33.9 33.9 34.1 0.2 D 19,047 75 161 7.9 36.0 36.0 36.3 0.3 E 19,144 179 1,319 1.0 39.5 39.5 40.4 0.9 F 19,795 185 281 4.6 40.2 40.2 40.9 0.7 G 20,159 58 151 5.7 43.1 43.1 43.6 0.5 H 21,576 36 160 5.8 56.9 56.9 56.9 0.0 I 21,836 111 427 2.2 59.4 59.4 59.5 0.1 J 22,308 105 367 2.5 60.1 60.1 60.3 0.2 K 22,493 245 1,645 0.6 66.6 66.6 66.8 0.2 L 23,019 54 163 5.7 68.4 68.4 68.5 0.1 M 23,526 166 283 3.3 74.5 74.5 74.5 0.0 N 24,043 204 392 2.4 80.1 80.1 80.2 0.1 O 24,864 378 256 3.7 86.6 86.6 86.6 0.0 P 25,590 167 181 5.2 96.8 96.8 96.8 0.0 1Feet above confluence with Arroyo Grande Creek TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: MEADOW CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 134 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE AB-H 8,506 176 1,746 6.4 67.4 67.4 0.0 9,240 110 972 11.5 73.1 73.1 0.0 10,032 100 1,172 9.6 84.7 84.7 0.1 10,270 109 1,051 10.7 90.0 90.0 0.1 11,030 199 2,372 4.7 94.2 94.2 0.0 11,774 100 715 15.7 104.8 104.8 0.0 12,313 120 1,523 7.4 113.6 113.6 0.6 12,545 197 3,020 3.7 114.8 114.8 0.5 12,883 110 1,661 6.7 116.2 116.2 0.3 13,364 118 1,109 10.1 118.2 118.2 0.9 14,235 179 2,156 5.2 124.8 124.8 0.1 14,847 125 1,266 8.8 127.1 127.1 0.0 15,682 121 1,341 8.4 134.6 134.6 0.0 16,368 104 1,332 8.4 139.6 139.6 0.0 *Data not available 1Feet above Pacific Ocean 2Controlled by coastal flooding – see Flood Insurance Rate Map for regulatory base flood elevation TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: MORRO CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 135 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 40 45 170 4.5 766.1 766.1 766.1 0.0 195 70 110 7.0 767.3 767.3 767.5 0.2 752 60 110 7.0 783.4 783.4 783.4 0.0 812 50 200 3.8 786.8 786.8 787.8 1.0 1,375 50 100 7.7 804.0 804.0 804.0 0.0 1,473 60 110 6.9 812.0 812.0 812.4 0.4 1,533 70 180 4.2 813.1 813.1 813.9 0.8 1Feet above center line of Vine Street TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: MOUNTAIN SPRINGS CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 136 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NGVD29)2 CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 686 2,320 3.4 206.5 206.5 207.5 1.0 1,320 3,791 2.1 207.5 207.5 208.5 0.8 2,255 1,087 7.4 207.5 207.5 208.3 0.8 2,355 809 9.9 208.9 208.9 209.6 0.7 2,508 4,006 2.0 215.4 215.4 216.2 0.8 3,326 4,423 1.8 215.6 215.6 216.5 0.9 3,511 2,752 2.9 215.7 215.7 216.5 0.8 3,775 681 11.8 215.8 215.8 216.5 0.7 4,066 1,279 6.3 218.3 218.3 218.6 0.3 4,462 2,871 2.8 219.1 219.1 219.7 0.6 4,963 3,534 2.0 220.0 220.0 220.7 0.7 5,217 4,125 1.7 220.1 220.1 220.8 0.7 5,333 1,965 3.7 220.1 220.1 220.8 0.7 5,887 3,003 2.4 220.9 220.9 221.8 0.9 6,468 4,348 1.7 221.2 221.2 222.1 0.9 6,917 8,497 0.8 221.3 221.3 222.2 0.9 7,471 7,273 0.9 221.4 221.4 222.3 0.9 8,026 6,488 1.0 221.5 221.5 222.4 0.9 8,501 3,970 1.7 221.6 221.6 222.5 0.9 9,187 5,201 1.3 221.9 221.9 222.9 1.0 1Feet above confluence with Santa Maria River 2This table is provided in NGVD 29 for use with the following FIRM panels: 06079C1639F, 06079C1902F, and 06079C1906F.

TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: NIPOMO CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 137 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 686 2,320 3.4 209.2 209.2 210.2 1.0 1,320 3,791 2.1 210.2 210.2 211.0 0.8 2,255 1,087 7.4 210.2 210.2 211.0 0.8 2,355 809 9.9 211.6 211.6 212.3 0.7 2,508 4,006 2.0 218.1 218.1 218.9 0.8 3,326 4,423 1.8 218.3 218.3 219.2 0.9 3,511 2,752 2.9 218.4 218.4 219.2 0.8 3,775 681 11.8 218.5 218.5 219.2 0.7 4,066 1,279 6.3 221.0 221.0 221.3 0.3 4,462 2,871 2.8 221.8 221.8 222.4 0.6 4,963 3,534 2.0 222.7 222.7 223.4 0.7 5,217 4,125 1.7 222.8 222.8 223.5 0.7 5,333 1,965 3.7 222.8 222.8 223.5 0.7 5,887 3,003 2.4 223.6 223.6 224.5 0.9 6,468 4,348 1.7 223.9 223.9 224.8 0.9 6,917 8,497 0.8 224.0 224.0 224.9 0.9 7,471 7,273 0.9 224.1 224.1 225.0 0.9 8,026 6,488 1.0 224.2 224.2 225.1 0.9 8,501 3,970 1.7 224.3 224.3 225.2 0.9 9,187 5,201 1.3 224.6 224.6 225.6 1.0 23,971 1,021 5.8 290.0 290.0 291.0 1.0 24,367 435 13.6 292.5 292.5 292.6 0.1 24,816 849 7.0 298.5 298.5 298.5 0.0 1Feet above confluence with Santa Maria River TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: NIPOMO CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 138 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 25,302 554 10.7 301.6 301.6 301.6 0.0 25,529 513 11.5 305.9 305.9 306.2 0.3 25,819 1,007 5.9 309.5 309.5 310.1 0.6 26,136 972 6.1 310.8 310.8 311.2 0.4 26,252 934 6.3 311.1 311.1 311.7 0.6 26,690 1,579 3.7 314.1 314.1 315.0 0.9 27,034 1,329 4.7 314.8 314.8 315.6 0.8 27,245 2,730 1.1 315.3 315.3 316.2 0.9 27,984 3,936 0.5 315.3 315.3 316.3 1.0 28,380 1,489 1.3 315.3 315.3 316.3 1.0 29,251 533 3.6 316.6 316.6 317.3 0.7 30,360 581 3.3 321.8 321.8 321.8 0.0 30,994 668 2.8 324.1 324.1 324.2 0.1 1Feet above confluence with Santa Maria River TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: NIPOMO CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 139 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 895 187 3.7 884.8 884.8 885.8 1.0 1,708 143 4.7 888.6 888.6 889.3 0.7 2,400 196 3.5 895.4 895.4 896.3 0.9 2,949 1,720 0.4 901.2 901.2 901.7 0.5 3,446 138 4.8 901.4 901.4 901.9 0.5 4,062 277 2.5 908.1 908.1 908.2 0.1 4,510 224 3.0 908.1 908.1 908.5 0.4 5,053 164 4.1 908.5 908.5 909.5 1.0 1Feet above confluence with Paloma Creek TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: NORTH FORK PALOMA CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 140 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 100 354 6.4 872.0 869.62 869.6 0.0 719 284 7.9 873.5 873.5 873.5 0.0 965 454 5.0 881.7 881.7 881.7 0.0 1,859 678 3.4 881.7 881.7 882.1 0.4 2,660 330 6.9 883.7 883.7 883.9 0.2 3,276 194 7.8 885.2 885.2 885.8 0.6 3,838 190 8.2 888.4 888.4 888.5 0.1 4,402 152 9.7 891.3 891.3 891.4 0.1 5,068 204 7.4 896.8 896.8 897.0 0.2 5,389 219 7.0 898.3 898.3 898.6 0.3 5,671 368 4.2 899.5 899.5 899.7 0.2 5,935 583 2.7 904.3 904.3 904.4 0.1 6,706 588 2.6 904.6 905.4 905.7 0.3 7,256 178 8.7 905.4 905.4 905.7 0.3 8,507 342 4.5 910.0 910.0 910.9 0.9 9,660 391 3.9 918.2 918.2 918.3 0.1 10,435 371 4.2 918.1 918.1 918.6 0.5 10,989 85 8.4 918.9 918.9 919.0 0.1 11,275 233 3.2 921.6 921.6 921.8 0.2 12,067 136 5.4 926.5 926.5 927.0 0.5 12,791 124 4.4 931.7 931.7 931.7 0.0 13,588 95 5.7 939.4 939.4 939.7 0.3 14,353 67 8.1 950.2 950.2 950.2 0.0 15,200 72 7.1 959.9 959.9 959.9 0.0 1Feet above confluence with Salinas River 2Elevation computed without consideration of backwater effects from Salinas River TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: PALOMA CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 141 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 60 35 90 4.4 750.9 750.9 750.9 0.0 144 30 120 3.3 751.0 751.0 751.0 0.0 598 70 90 4.4 756.8 756.8 757.0 0.2 723 50 70 5.7 760.0 760.0 760.0 0.0 899 75 1,140 0.4 783.5 783.5 783.5 0.0 1,185 35 500 0.8 783.5 783.5 783.5 0.0 1Feet above center line of Spring Street TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: PEACHY CANYON CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 142 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 2,772 506 8,066 1.8 33.9 33.9 34.5 0.6 3,432 432 6,836 2.2 33.9 33.9 34.5 0.6 4,250 144 2,401 6.1 34.8 34.8 35.5 0.7 4,731 748 8,592 1.7 35.9 35.9 36.5 0.6 5,755 566 5,499 2.7 36.2 36.2 36.8 0.6 F 6,547 504 3,780 3.9 37.1 37.1 37.8 0.7 G 7,339 364 2,191 6.7 39.6 39.6 40.5 0.9 1Feet above Pacific Ocean TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: PISMO CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 143 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 634,853 575 5,622 7.6 675.7 675.7 676.1 0.5 635,864 464 5,841 7.4 678.0 678.0 678.7 0.3 636,894 428 5,264 8.2 680.1 680.1 681.0 0.9 637,915 486 5,887 7.3 682.8 682.8 683.7 0.9 637,915 486 5,887 7.3 682.8 682.8 683.7 0.9 640,022 612 7,162 6.0 686.1 686.1 686.9 0.8 641,032 691 9,310 4.6 687.9 687.9 688.4 0.5 642,121 679 8,165 5.3 689.2 689.2 689.9 0.7 643,287 542 6,796 6.3 691.1 691.1 691.3 0.2 644,867 463 6,656 6.6 694.1 694.1 694.2 0.1 646,192 488 7,187 5.8 696.8 696.8 697.5 0.7 647,232 909 11,493 3.7 698.1 698.1 698.8 0.7 648,377 868 8,578 4.9 699.1 699.1 699.7 0.6 649,465 782 7,416 5.7 700.7 700.7 701.6 0.9 650,707 765 7,944 5.3 703.1 703.1 704.0 0.9 652,714 605 6,973 6.0 707.3 707.3 708.2 0.9 654,878 628 6,889 6.1 711.2 711.2 711.7 0.5 657,043 1,401 9,514 4.4 715.3 715.3 715.9 0.6 658,997 1,360 8,196 5.1 717.9 717.9 718.6 0.7 661,214 1,417 11,694 3.6 721.4 721.4 722.2 0.8 663,326 1,129 9,090 4.6 724.1 724.1 725.0 0.9 665,544 739 6,517 6.4 729.6 729.6 729.8 0.2 668,131 1,069 8,111 5.2 735.0 735.0 735.8 0.8 670,138 1,063 4.3 738.4 738.4 739.3 0.9 672,197 761 6.8 741.3 741.3 742.1 0.8 Z 673,147 773 7,917 5.3 743.7 743.7 744.5 0.8 TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SALINAS RIVER AND INCORPORATED AREAS Table 23: Floodway Data (continued) 144 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 675,206 1,044 4.0 746.8 746.8 747.2 0.4 677,477 956 4.7 750.7 750.7 750.9 0.2 679,536 677 6.6 755.8 755.8 756.1 0.3 681,437 565 5.8 759.6 759.6 760.3 0.7 682,334 499 7.5 761.3 761.3 761.9 0.6 684,288 588 5.8 766.8 766.8 767.3 0.5 686,347 760 4.7 770.1 770.1 771.1 1.0 688,090 779 4.9 773.1 773.1 773.7 0.6 689,832 685 5.9 776.0 776.0 776.4 0.4 691,944 923 4.9 780.9 780.9 781.2 0.3 694,056 612 6.4 787.7 787.7 787.9 0.2 696,432 1,325 3.4 792.9 792.9 793.0 0.1 698,597 1,408 3.7 797.1 797.1 797.2 0.1 700,498 1,107 4.5 801.1 801.1 802.0 0.9 702,451 946 4.7 808.0 808.0 808.9 0.9 704,299 852 4.7 814.1 814.1 814.4 0.3 705,989 664 5.2 817.7 817.7 818.2 0.5 708,048 932 4.9 821.0 821.0 821.4 0.4 709,685 590 6.2 826.4 826.4 826.4 0.0 AT 712,114 358 4,118 6.8 834.2 834.2 834.5 0.3 AU 713,856 224 2,910 9.6 841.3 841.3 841.6 0.3 AV 716,179 505 4,940 5.4 845.7 845.7 846.1 0.4 AW 718,661 1,810 8,443 3.1 849.9 849.9 850.0 0.1 AX 721,776 390 3,932 5.9 861.7 861.7 861.7 0.0 AY 724,099 1,267 7,793 3.0 865.6 865.6 865.6 0.0 AZ 726,211 1,356 7,241 3.1 869.0 869.0 869.0 0.0 1Feet above confluence with Pacific Ocean TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SALINAS RIVER AND INCORPORATED AREAS Table 23: Floodway Data (continued) 145 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE BA 728,534 764 4,959 4.5 874.1 874.1 874.1 0.0 BB 730,805 783 4,775 4.4 880.4 880.4 880.5 0.1 BC 733,286 806 5,583 3.8 885.6 885.6 885.8 0.2 BD 736,190 639 4,775 4.4 892.7 892.7 892.8 0.1 BE 738,197 490 4,289 4.9 898.0 898.0 898.0 0.0 1Feet above confluence with Pacific Ocean TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SALINAS RIVER AND INCORPORATED AREAS Table 23: Floodway Data (continued) 146 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE A – U2 * * * * * * * * V 140,472 1,521 14,642 6.5 583.6 583.6 584.4 0.8 W 147,033 892 13,902 6.3 599.3 599.3 599.8 0.5 X 148,750 1,117 18,143 4.8 600.5 600.5 601.1 0.6 Y 153,733 1,267 14,433 6.1 604.4 604.4 604.8 0.4 Z 156,346 891 12,738 6.9 608.8 608.8 609.2 0.4 AA 167,589 1,045 7,260 7.5 624.5 624.5 625.1 0.6 AB 171,754 804 7,891 6.9 631.3 631.3 631.7 0.4 AC 178,057 1,655 9,761 5.6 639.8 639.8 640.5 0.7 AD 180,250 2,073 17,342 3.2 645.0 645.0 645.2 0.2 AE 188,764 848 8,187 4.9 661.5 661.5 662.4 0.9 1 Distances are measure in feet approximately 4.5 miles downstream of Cattleman Road 2 XS A – U are located in Monterey County, CA. For more information, reference the Monterey County, CA FIS Report TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SALINAS RIVER REACH 1 AND INCORPORATED AREAS Table 23: Floodway Data (continued) 147 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE A 143 426 3,148 7 13.4 13.4 14.4 1.0 B 2,154 295 3,690 6 15.5 15.5 16.2 0.7 C 2,640 363 3,946 5.6 16.0 16.0 16.0 0.0 3,890 606 5,995 3.7 17.6 17.6 18.1 0.5 5,240 348 3,757 5.9 18.7 18.7 19.3 0.6 8,904 553 6,410 3.5 30.2 30.2 30.7 0.5 11,853 778 11,330 2 32.7 32.7 33.3 0.6 13,216 680 8,074 2.7 33.2 33.2 33.8 0.6 13,847 886 5,300 4.2 34.2 34.2 34.7 0.5 14,484 703 7,831 2.8 37.4 37.4 37.9 0.5 15,322 1,014 11,032 2.5 39.2 39.2 39.9 0.7 17,368 1,314 7,653 3.1 39.9 39.9 40.5 0.6 18,759 * * * 42.4 * * * 19,488 * * * 47.6 * * * 23,407 * * * 56.3 * * * 25,770 * * * 63.9 * * * 27,317 * * * 71.0 * * * 31,129 * * * 76.9 * * * 33,822 * * * 88.8 * * * 34,978 * * * 91.7 * * * 36,694 * * * 95.0 * * * 37,625 * * * 97.2 * * * 1Feet above Pacific Ocean *Floodway data not calculated for this cross section TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SAN LUIS OBISPO CREEK SOUTH AND INCORPORATED AREAS Table 23: Floodway Data (continued) 148 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE D 38,016 241 3,231 4.1 101.7 101.7 102.5 0.8 E 38,886 144 1,492 9.0 104.3 104.3 104.6 0.3 F 40,128 206 2,020 6.6 111.9 111.9 112.0 0.1 G 41,184 183 1,740 7.7 114.9 114.9 114.9 0.0 H 42,082 163 1,564 8.6 118.5 118.5 118.5 0.0 I 42,768 192 1,923 7.0 121.3 121.3 121.3 0.0 J 43,718 80 804 16.7 126.8 126.8 126.9 0.1 K – AO* 1Feet above mouth *Data not available TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SAN LUIS OBISPO CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 149 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 545 1,227 11.2 896.6 896.32 896.7 0.4 1,745 1,541 9.0 902.0 902.0 0.0 3,503 1,552 8.8 911.8 912.3 0.5 4,030 2,344 4.1 913.8 914.2 0.4 5,458 751 12.4 921.9 921.9 0.0 6,545 919 10.2 930.8 930.8 0.0 7,717 1,535 6.1 939.7 939.7 0.0 9,021 1,027 9.1 943.6 943.7 0.1 10,083 783 11.8 947.6 947.6 0.0 11,333 1,320 5.4 953.9 954.8 0.9 12,469 703 10.0 956.5 956.8 0.3 13,459 1,333 5.5 965.4 965.4 0.0 21,799 733 7.5 1,003.8 1,004.1 0.3 22,195 792 6.9 1,005.2 1,005.3 0.1 22,818 650 8.4 1,005.4 1,006.3 0.9 24,091 526 10.2 1,011.0 1,011.2 0.2 24,973 624 8.6 1,015.3 1,015.3 0.0 1Feet above confluence with Salinas River 2 Elevation computed without consideration of backwater effects from Salinas River TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SANTA MARGARITA CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 150 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 1,536 1,512 11.9 14.1 14.1 14.1 0.0 2,191 2,737 6.6 16.9 16.9 17.9 1.0 2,666 1,357 13.3 18.1 18.1 18.1 0.0 3,168 1,587 11.3 21.3 21.3 21.3 0.0 3,353 2,532 6.0 24.3 24.3 24.3 0.0 3,865 1,999 7.7 25.6 25.6 25.6 0.0 4,467 1,622 9.4 27.9 27.9 27.9 0.0 4,974 1,845 8.3 31.1 31.1 31.1 0.0 5,449 2,082 7.3 33.4 33.4 33.4 0.0 5,940 3,433 3.8 34.7 34.7 34.7 0.0 6,574 2,355 5.5 35.5 35.5 35.5 0.0 7,080 1,596 8.1 36.5 36.5 36.5 0.0 7,593 4,069 4.4 40.7 40.7 41.4 0.7 7,968 3,634 5.0 41.2 41.2 42.1 0.9 8,564 3,493 5.2 42.4 42.4 43.4 1.0 9,071 1,231 14.6 43.9 43.9 43.9 0.0 9,504 3,092 5.8 47.8 47.8 48.8 1.0 9,926 1,934 9.3 49.2 49.2 50.1 0.9 10,307 2,453 7.3 50.6 50.6 51.6 1.0 10,676 1,683 10.7 51.2 51.2 52.1 0.9 11,088 1,540 11.7 53.3 53.3 54.0 0.7 11,906 1,564 11.5 59.3 59.3 59.3 0.0 12,302 2,049 8.8 60.7 60.7 0.6 12,672 2,064 8.7 61.5 61.5 1.0 13,174 3,060 5.9 63.9 63.9 0.9 13,781 2,246 8.0 65.3 65.3 0.6 1Feet above Pacific Ocean TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SANTA ROSA CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 151 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 14,177 2,590 6.9 66.9 66.9 0.4 14,516 1,416 12.7 67.3 67.3 0.0 14,942 3,825 4.7 72.0 72.0 1.0 15,418 4,073 4.4 72.5 72.5 1.0 15,956 2,973 6.1 72.9 72.9 1.0 16,400 3,391 5.3 73.7 73.7 0.8 16,658 3,448 5.2 74.0 74.0 0.8 17,350 3,448 5.2 74.0 74.0 0.8 17,905 1,241 14.5 77.8 77.8 1.0 18,464 1,804 10.0 85.3 85.3 0.0 18,929 2,318 7.8 87.5 87.5 0.0 19,209 1,951 9.2 87.8 87.8 0.1 19,483 1,036 17.4 92.1 92.1 0.0 20,117 1,824 9.9 100.7 100.7 0.0 1Feet above Pacific Ocean TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SANTA ROSA CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 152 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 927 42 90 3.6 799.5 799.5 799.5 0.0 1,536 40 82 3.9 811.1 811.1 811.1 0.0 1Feet above confluence with Toad Creek TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SOUTH BRANCH TOAD CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 153 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 350 35 60 5.3 773.8 773.8 774.1 0.3 1,040 45 120 2.7 778.6 778.6 779.3 0.7 1,040 45 120 2.7 778.6 778.6 779.3 0.7 2,850 15 30 7.7 789.6 789.6 789.6 0.0 1Feet above confluence with Unnamed Creek No. 1 TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: SOUTH BRANCH UNNAMED CREEK NO. 1 AND INCORPORATED AREAS Table 23: Floodway Data (continued) 154 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 100 190 10.1 740.7 735.12 735.0 0.0 655 180 10.6 740.7 739.12 739.0 0.1 1,705 77 296 6.5 784.1 784.1 784.6 0.5 2,276 408 6.4 753.1 753.1 753.1 0.0 5,217 210 3.1 761.1 761.1 761.4 0.3 6,104 150 4.4 766.1 766.1 766.1 0.0 7,048 150 4.4 770.6 770.6 770.8 0.2 7,773 300 2.2 777.6 777.6 777.8 0.2 8,509 130 5.1 779.1 779.1 779.8 0.7 9,206 160 4.1 784.6 784.6 784.9 0.3 10,181 230 2.9 792.5 792.5 792.6 0.1 10,381 320 2.1 792.7 792.7 792.9 0.2 11,097 41 8.4 796.1 796.1 796.1 0.0 1Feet above confluence with Salinas River 2Elevation computed without consideration of backwater effects from Salinas River *Data not available TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: TOAD CREEK (MAIN AND NORTH BRANCH) AND INCORPORATED AREAS Table 23: Floodway Data (continued) 155 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 1,850 37 206 4.6 724.8 724.8 725.8 1.0 2,205 46 255 3.7 725.9 725.9 726.5 0.6 3,285 30 100 9.6 740.8 740.8 740.8 0.0 4,375 50 190 5.1 751.0 751.0 751.0 0.0 5,334 40 230 4.2 756.0 756.0 756.1 0.1 6,401 35 130 7.4 758.9 758.9 759.8 0.9 7,418 45 160 6.0 763.1 763.1 763.9 0.8 8,308 50 170 5.6 767.3 767.3 767.8 0.5 9,048 65 190 5.1 771.1 771.1 771.2 0.1 10,038 30 150 4.5 775.5 775.5 775.7 0.2 10,968 65 230 2.9 779.7 779.7 779.7 0.0 11,728 50 170 3.9 785.6 785.6 785.6 0.0 12,753 35 80 8.4 791.1 791.1 791.1 0.0 13,198 30 130 5.2 796.2 796.2 796.5 0.3 13,353 85 260 2.5 801.1 801.1 801.8 0.7 14,190 75 230 2.3 801.2 801.2 802.1 0.9 15,005 75 140 3.7 804.2 804.2 804.3 0.1 15,725 40 140 3.7 807.0 807.0 807.1 0.1 16,370 80 310 1.7 808.0 808.0 808.2 0.2 16,700 60 270 1.8 811.0 811.0 811.3 0.3 17,736 50 210 2.3 811.2 811.2 811.5 0.3 18,750 20 80 5.8 815.9 815.9 816.8 0.9 19,445 30 120 3.9 820.0 820.0 820.4 0.4 20,641 30 80 5.8 823.7 823.7 823.9 0.2 21,466 86 90 4.9 828.4 828.4 828.4 0.0 22,271 101 85 5.2 831.1 831.1 831.1 0.0 1Feet above confluence with Salinas River TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: UNNAMED CREEK NO. 1 AND INCORPORATED AREAS Table 23: Floodway Data (continued) 156 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 792 1,049 2.1 38.6 38.6 39.4 0.8 950 538 4.1 38.7 38.7 39.4 0.7 1,109 526 4.2 39.0 39.0 39.8 0.8 1,320 179 12.3 40.4 40.4 40.4 0.0 1,573 453 4.9 45.0 45.0 45.0 0.0 1Feet above confluence with Pacific Ocean TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: WILLOW CREEK AND INCORPORATED AREAS Table 23: Floodway Data (continued) 157 LOCATION FLOODWAY 1% ANNUAL CHANCE FLOOD WATER SURFACE ELEVATION (FEET NAVD88) CROSS SECTION DISTANCE1 WIDTH (FEET) SECTION AREA (SQ. FEET) MEAN VELOCITY (FEET/ SEC) REGULATORY WITHOUT FLOODWAY WITH FLOODWAY INCREASE 6,241 364 6.9 993.8 993.8 994.0 0.2 6,923 582 4.4 997.2 997.2 997.8 0.6 7,083 1,298 2.0 1,000.9 1,000.9 1,001.6 0.7 9,608 197 10.3 1,010.1 1,010.1 1,010.1 0.0 10,536 222 8.9 1,014.6 1,014.6 1,014.6 0.0 11,626 301 6.8 1,021.3 1,021.3 1,021.3 0.0 12,076 266 7.6 1,022.9 1,022.9 1,023.0 0.1 6,241 364 6.9 993.8 993.8 994.0 0.2 6,923 582 4.4 997.2 997.2 997.8 0.6 7,083 1,298 2.0 1,000.9 1,000.9 1,001.6 0.7 1Feet above confluence with Santa Margarita Creek *Data not available TABLE 23 FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATA SAN LUIS OBISPO COUNTY, CALIFORNIA FLOODING SOURCE: YERBA BUENA CREEK AND INCORPORATED AREAS 158
Table 24: Flood Hazard and Non-Encroachment Data for Selected Streams [Not Applicable to this Flood Risk Project]

6.4 Coastal Flood Hazard Mapping
Flood insurance zones and BFEs including the wave effects were identified on each transect based on the results from the onshore wave hazard analyses. Between transects, elevations were interpolated using topographic maps, land-use and land-cover data, and knowledge of coastal flood processes to determine the aerial extent of flooding. Sources for topographic data are shown in Table 22.

Zone VE is subdivided into elevation zones and BFEs are provided on the FIRM.

The limit of Zone VE shown on the FIRM is defined as the farthest inland extent of any of these criteria (determined for the 1-percent-annual-chance flood condition):

The primary frontal dune zone is defined in 44 CFR Section 59.1 of the NFIP regulations. The primary frontal dune represents a continuous or nearly continuous mound or ridge of sand with relatively steep seaward and landward slopes that occur immediately landward and adjacent to the beach. The primary frontal dune zone is subject to erosion and overtopping from high tides and waves during major coastal storms. The inland limit of the primary frontal dune zone occurs at the point where there is a distinct change from a relatively steep slope to a relatively mild slope.

The wave runup zone occurs where the (eroded) ground profile is 3.0 feet or more below the 2-percent wave runup elevation.

The wave overtopping splash zone is the area landward of the crest of an overtopped barrier, in cases where the potential 2-percent wave runup exceeds the barrier crest elevation by 3.0 feet or more.

The breaking wave height zone occurs where 3-foot or greater wave heights could occur (this is the area where the wave crest profile is 2.1 feet or more above the total stillwater elevation).

The high-velocity flow zone is landward of the overtopping splash zone (or area on a sloping beach or other shore type), where the product of depth of flow times the flow velocity squared (hv2
) is greater than or equal to 200 ft 3/sec2. This zone may only be used on the Pacific Coast.

The SFHA boundary indicates the limit of SFHAs shown on the FIRM as either “V” zones or “A” zones.

Table 25 indicates the coastal analyses used for floodplain mapping and the criteria used to determine the inland limit of the open-coast Zone VE and the SFHA boundary at each transect.
159
Table 25: Summary of Coastal Transect Mapping Considerations Coastal
Transect
Primary
Frontal Dune
(PFD)
Identified
Wave Runup
Analysis
Wave Height
Analysis
Zone VE
Limit
SFHA
Boundary
Zone
Designation
and BFE
(ft NAVD 88)
Zone
Designation
and BFE
(ft NAVD 88)
1 VE 22 N/A Runup Runup
2 VE 20 N/A Overtopping Overtopping
3 VE 23 N/A Runup Runup
4 VE 16 N/A Runup Runup
5 VE 17 N/A Runup Runup
6 VE 22 N/A Runup Runup
7 VE 38 N/A Overtopping Overtopping
8 VE 21 N/A Runup Runup
9 VE 31 N/A Overtopping Overtopping
10 VE 20 N/A Overtopping Overtopping
11 VE 18 N/A Runup Runup
12 VE 37 N/A Runup Runup
13 VE 17 N/A Runup Runup
14 VE 17 N/A Overtopping Overtopping
15 VE 21 N/A Runup Runup
16 VE 15 N/A Runup Runup
17 VE 37 N/A Overtopping Overtopping
18 VE 20 N/A Runup Runup
19 VE 24 N/A Overtopping Overtopping
20 VE 19 N/A Runup Runup
21 VE 20 N/A Runup Runup
22 VE 18 N/A Runup Runup
23 VE 20 N/A Runup Runup
24 VE 29 N/A Overtopping Overtopping
25 VE 24 N/A Overtopping Overtopping
26 VE 18 N/A Runup Runup
27 VE 23 N/A Runup Runup
28 VE 19 N/A Runup Runup
29 VE 29 N/A Overtopping Overtopping
30 VE 26 N/A Overtopping Overtopping
Table 25: Summary of Coastal Transect Mapping Considerations (continued) 160
Coastal
Transect
Primary
Frontal Dune
(PFD)
Identified
Wave Runup
Analysis
Zone
Designation
and BFE
(ft NAVD88)
Wave Height
Analysis
Zone
Designation
and BFE
(ft NAVD88)
Zone VE
Limit
SFHA
Boundary
31 VE 24 N/A Runup Runup
32 VE 15 N/A Overtopping Overtopping
33 VE 15 N/A Overtopping Overtopping
34 VE 17 N/A Runup Runup
35 VE 19 N/A Runup Runup
36 VE 17 N/A Runup Runup
37 VE 18 N/A Runup Runup
38 VE 17 N/A Runup Runup
39 VE 19 N/A Runup Runup
40 VE 14 N/A PFD PFD
41 VE 15 N/A PFD PFD
42 VE 16 N/A PFD PFD
43 VE 22 N/A PFD PFD
44 VE 26 N/A PFD PFD
45 VE 23 N/A PFD PFD
46 VE 17 N/A Runup Runup
47 VE 26 N/A Runup Runup
48 VE 22 N/A Runup Runup
49 VE 23 N/A Runup Runup
50 VE 39 N/A Runup Runup
51 VE 22 N/A Overtopping Overtopping
52 VE 19 N/A Runup Runup
53 VE 10 N/A Runup Runup
54 VE 28 N/A Overtopping Overtopping
55 VE 14 N/A Runup Runup
56 VE 22 N/A Runup Runup
57 VE 15 N/A Overtopping Overtopping
58 VE 16 N/A Runup Runup
59 VE 17 N/A Runup Runup
Table 25: Summary of Coastal Transect Mapping Considerations (continued) 161
Coastal
Transect
Primary
Frontal Dune
(PFD)
Identified
Wave Runup
Analysis
Wave Height
Analysis
Zone VE
Limit
SFHA
Boundary
Zone
Designation
and BFE
(ft NAVD 88)
Zone
Designation
and BFE
(ft NAVD 88)
60 VE 33 N/A Runup Runup
61 VE 25 N/A Runup Runup
62 VE 19 N/A Runup Runup
63 VE 18 N/A Overtopping Overtopping
64 VE 17 N/A Runup Runup
65 VE 27 N/A Runup Runup
66 VE 21 N/A Runup Runup
67 VE 14 N/A Runup Runup
68 VE 14 N/A Runup Runup
69 VE 19 N/A Overtopping Overtopping
70 VE 15 N/A Runup Runup
71 VE 14 N/A Runup Runup
72 VE 15 N/A PFD PFD
73 VE 14 N/A PFD PFD
74 VE 15 N/A PFD PFD
75 VE 16 N/A PFD PFD
76 VE 15 N/A Runup Runup
77 VE 25 N/A Overtopping Overtopping
78 VE 23 N/A Runup Runup
79 VE 20 N/A Runup Runup
80 VE 12 N/A Runup Runup
81 N/A AE 9-10 WHAFIS WHAFIS
82 VE 12 N/A Runup Runup
83 N/A AE 9-10 WHAFIS WHAFIS

6.5 FIRM Revisions
This FIS Report and the FIRM are based on the most up-to-date information available to FEMA at the time of its publication; however, flood hazard conditions change over time.

Communities or private parties may request flood map revisions at any time. Certain types of requests require submission of supporting data. FEMA may also initiate a revision.

Revisions may take several forms, including Letters of Map Amendment (LOMAs), Letters of Map Revision Based on Fill (LOMR-Fs), Letters of Map Revision (LOMRs) (referred to collectively as Letters of Map Change (LOMCs)), Physical Map Revisions (PMRs), and FEMA-contracted restudies. These types of revisions are further described below. Some 162
of these types of revisions do not result in the republishing of the FIS Report. To assure that any user is aware of all revisions, it is advisable to contact the community repository of flood-hazard data (shown in Table 30, “Map Repositories”).

6.5.1 Letters of Map Amendment
A LOMA is an official revision by letter to an effective NFIP map. A LOMA results from an administrative process that involves the review of scientific or technical data submitted by the owner or lessee of property who believes the property has incorrectly been included in a designated SFHA. A LOMA amends the currently effective FEMA map and establishes that a specific property is not located in a SFHA. A LOMA cannot be issued for properties located on the PFD (primary frontal dune).

To obtain an application for a LOMA, visit www.fema.gov/letter-map-amendment-loma and download the form “MT-1 Application Forms and Instructions for Conditional and Final Letters of Map Amendment and Letters of Map Revision Based on Fill”. Visit the “Flood Map-Related Fees” section to determine the cost, if any, of applying for a LOMA.

FEMA offers a tutorial on how to apply for a LOMA. The LOMA Tutorial Series can be accessed at www.fema.gov/online-tutorials. For more information about how to apply for a LOMA, call the FEMA Map Information eXchange; toll free, at 1-877-FEMA MAP (1-877-336-2627).

6.5.2 Letters of Map Revision Based on Fill
A LOMR-F is an official revision by letter to an effective NFIP map. A LOMR-F states FEMA’s determination concerning whether a structure or parcel has been elevated on fill above the base flood elevation and is, therefore, excluded from the SFHA.

Information about obtaining an application for a LOMR-F can be obtained in the same manner as that for a LOMA, by visiting www.fema.gov/letter-map-amendment-loma for the “MT-1 Application Forms and Instructions for Conditional and Final Letters of Map Amendment and Letters of Map Revision Based on Fill” or by calling the FEMA Map Information eXchange, toll free, at 1-877-FEMA MAP (1-877-336-2627). Fees for applying for a LOMR-F, if any, are listed in the “Flood Map-Related Fees” section.

A tutorial for LOMR-F is available at www.fema.gov/online-tutorials. 6.5.3 Letters of Map Revision A LOMR is an official revision to the currently effective FEMA map. It is used to change flood zones, floodplain and floodway delineations, flood elevations and planimetric features. All requests for LOMRs should be made to FEMA through the chief executive officer of the community, since it is the community that must adopt any changes and revisions to the map. If the request for a LOMR is not submitted through the chief executive officer of the community, evidence must be submitted that the community has been notified of the request.

To obtain an application for a LOMR, visit www.fema.gov/media-library/assets/ documents/1343 and download the form “MT-2 Application Forms and Instructions for Conditional Letters of Map Revision and Letters of Map Revision”. Visit the “Flood MapRelated Fees” section to determine the cost of applying for a LOMR. For more information 163
about how to apply for a LOMR, call the FEMA Map Information eXchange; toll free, at 1- 877-FEMA MAP (1-877-336-2627) to speak to a Map Specialist.

Previously issued mappable LOMCs (including LOMRs) that have been incorporated into the San Luis Obispo County FIRM are listed in Table 26. Please note that this table only includes LOMCs that have been issued on the FIRM panels updated by this map revision.

For all other areas within this county, users should be aware that revisions to the FIS Report made by prior LOMRs may not be reflected herein and users will need to continue to use the previously issued LOMRs to obtain the most current data.

Table 26: Incorporated Letters of Map Change
Case Number Effective Date Flooding Source FIRM Panel(s) 22-09-1729P 10/2/2023 Highway 101
Tributary Creek
06079C1363J
06079C1364G1
1 Although a portion of LOMR 22-09-1729P falls within the scope of this map revision, panel 06079C1364G was not revised. Therefore, users must continue to refer to the annotated FIRM attachment for this LOMR for FIRM panel 06079C1364G.

6.5.4 Physical Map Revisions
A Physical Map Revisions (PMR) is an official republication of a community’s NFIP map to effect changes to base flood elevations, floodplain boundary delineations, regulatory floodways and planimetric features. These changes typically occur as a result of structural works or improvements, annexations resulting in additional flood hazard areas or correction to base flood elevations or SFHAs.

The community’s chief executive officer must submit scientific and technical data to FEMA to support the request for a PMR. The data will be analyzed and the map will be revised if warranted. The community is provided with copies of the revised information and is afforded a review period. When the base flood elevations are changed, a 90-day appeal period is provided. A 6-month adoption period for formal approval of the revised map(s) is also provided.

For more information about the PMR process, please visit www.fema.gov and visit the “Flood Map Revision Processes” section.

6.5.5 Contracted Restudies
The NFIP provides for a periodic review and restudy of flood hazards within a given community. FEMA accomplishes this through a national watershed-based mapping needs assessment strategy, known as the Coordinated Needs Management Strategy (CNMS).

The CNMS is used by FEMA to assign priorities and allocate funding for new flood hazard analyses used to update the FIS Report and FIRM. The goal of CNMS is to define the validity of the engineering study data within a mapped inventory. The CNMS is used to track the assessment process, document engineering gaps and their resolution, and aid in prioritization for using flood risk as a key factor for areas identified for flood map updates.

Visit www.fema.gov to learn more about the CNMS or contact the FEMA Regional Office listed in Section 8 of this FIS Report.
164

6.5.6 Community Map History
The current FIRM presents flooding information for the entire geographic area of San Luis Obispo County. Previously, separate FIRMs, Flood Hazard Boundary Maps (FHBMs) and/or Flood Boundary and Floodway Maps (FBFMs) may have been prepared for the incorporated communities and the unincorporated areas in the county that had identified SFHAs. Current and historical data relating to the maps prepared for the project area are presented in Table 27, “Community Map History.” A description of each of the column headings and the source of the date is also listed below.

Community Name includes communities falling within the geographic area shown on the FIRM, including those that fall on the boundary line, nonparticipating communities, and communities with maps that have been rescinded. Communities with No Special Flood Hazards are indicated by a footnote. If all maps (FHBM, FBFM, and FIRM) were rescinded for a community, it is not listed in this table unless SFHAs have been identified in this community.

Initial Identification Date (First NFIP Map Published) is the date of the first NFIP map that identified flood hazards in the community. If the FHBM has been converted to a FIRM, the initial FHBM date is shown. If the community has never been mapped, the upcoming effective date or “pending” (for Preliminary FIS Reports) is shown. If the community is listed in Table 27 but not identified on the map, the community is treated as if it were unmapped.

Initial FHBM Effective Date is the effective date of the first FHBM. This date may be the same date as the Initial NFIP Map Date.

FHBM Revision Date(s) is the date(s) that the FHBM was revised, if applicable.

Initial FIRM Effective Date is the date of the first effective FIRM for the community.

FIRM Revision Date(s) is the date(s) the FIRM was revised, if applicable. This is the revised date that is shown on the FIRM panel, if applicable. As countywide studies are completed or revised, each community listed should have its FIRM dates updated accordingly to reflect the date of the countywide study. Once the FIRMs exist in countywide format, as PMRs of FIRM panels within the county are completed, the FIRM Revision Dates in the table for each community affected by the PMR are updated with the date of the PMR, even if the PMR did not revise all the panels within that community.

The initial effective date for the San Luis Obispo County FIRMs in countywide format was 08/28/2008.
165
Table 27: Community Map History
Community Name
Initial
Identification
Date
Initial
FHBM
Effective
Date
FHBM
Revision
Date(s)
Initial FIRM
Effective
Date
FIRM
Revision
Date(s)
Arroyo Grande,
City of 06/07/1974 06/07/1974 02/06/1979
10/10/1975
09/19/1984
06/06/2024
05/16/2017
11/16/2012
08/28/2008
Atascadero, City
of 09/16/1980 09/16/1980 N/A 01/20/1982 11/16/2012
08/28/2008
El Paso de
Robles, City of 02/15/1974 02/15/1974 07/23/1976 09/16/1981 06/06/2024
11/16/2012
08/28/2008
Grover Beach,
City of 06/21/1974 06/21/1974 09/26/1975 08/01/1984
06/06/2024
05/16/2017
11/16/2012
08/28/2008
11/05/1997
Morro Bay, City of 05/31/1974 05/31/1974 12/05/1975 12/18/1979 05/16/2017
11/16/2012
8/28/2008
11/01/1985
Pismo Beach,
City of 03/26/1976 03/26/1976 N/A 08/01/1984
06/06/2024
05/16/2017
11/16/2012
08/28/2008
11/05/1997
San Luis Obispo,
City of 10/26/1973 10/26/1973 05/21/1976 04/16/1979
06/06/2024
05/16/2017
11/16/2012
08/28/2008
07/07/1981
San Luis Obispo
County,
Unincorporated
Areas
01/03/1975 01/03/1975 11/22/1977 07/05/1982
06/06/2024
05/16/2017
11/16/2012
08/28/2008
02/04/2004
06/03/1991
07/18/1985
SECTION 7.0 – CONTRACTED STUDIES AND COMMUNITY COORDINATION

7.1 Contracted Studies
Table 28 provides a summary of the contracted studies, by flooding source, that are included in this FIS Report.
166
Table 28: Summary of Contracted Studies Included in this FIS Report Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Alamo Creek 07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
Anderson
Canyon
Creek
07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
Arroyo
Grande
Creek
06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Atascadero
Creek 07/20/1981
George S.

Nolte and
Associates
H-4722 December
1979 Atascadero, City of
Brizziolari
Creek 10/1978
USACE,
LosAngeles
District,
California
IAA-H-74 and
IAA-H- 16-75,
Project Order
No.s 13 and
22 June 1977
San Luis Obispo,
City of; San Luis
Obispo County,
Unincorporated
Areas
Canyon
Creek No. 1 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Canyon
Creek No. 1 03/19/1984 USACE IAA-H-10- 77 January 1983
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Canyon
Creek No. 2 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Canyon
Creek No. 2 03/19/1984 USACE IAA-H-10- 77 January 1983
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Carpenter
Canyon
Creek
06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 167
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Cayucos
Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Chorro
Creek 12/18/1979 U.S.Geological Survey
IAA-H-17-75
and IAA- H-8-
76, Project
Order No.s 8
and 13
June 1977
Morro Bay, City of;
San Luis Obispo
County,
Unincorporated
Areas
Corbett
Canyon
Creek
03/19/1984 USACE IAA-H-10- 77 January
1983
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Corbett
Canyon
Creek
06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Davenport
Creek 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Davis
Canyon
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Deleissigues
Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Dry Creek 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
El Paso De Robles,
City of; San Luis
Obispo County,
Unincorporated
Areas
Dry Creek 07/05/1982
George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of; San Luis
Obispo County,
Unincorporated
Areas
East Branch
Huerhuero
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 168
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
East Branch
San Luis
Obispo
Creek
06/06/2024 Schaaf &
Wheeler
HSFE60-15-
D-0005
March
2023
San Luis Obispo
County,
Unincorporated
Areas
East Branch
San Luis
Obispo
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
East Fork
Meadow
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
Arroyo Grande, City
of
East Fork
Meadow
Creek
03/19/1984 USACE IAA-H-10- 77 January
1983
Arroyo Grande, City
of
Froom Creek 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Graves
Creek 07/20/1981
George S.

Nolte and
Associates
H-4722 December
1979
Atascadero, City of;
San Luis Obispo
County,
Unincorporated
Areas
Harford
Canyon
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Highway 101
Tributary
Creek
03/19/1984 USACE IAA-H-10- 77 January
1983
Arroyo Grande, City
of
Huerhuero
Creek 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
El Paso De Robles,
City of; San Luis
Obispo County
Huerhuero
Creek 07/05/1982
George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of; San Luis
Obispo County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 169
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Little
Cayucos
Creek
06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Little Morro
Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Los Berros
Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Los Berros
Creek 02/04/2004
California
Department
of Water
Resources,
San Joaquin
District, in
collaboration
with the San
Luis Obispo
County
Department
of
Engineering
NA June 2001
San Luis Obispo
County,
Unincorporated
Areas
Meadow
Creek 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
February
2020
Arroyo Grande, City
of; Grover Beach,
City of; Pismo
Beach, City of; San
Luis Obispo County
Middle
Branch
Huerhuero
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005 May 2020
San Luis Obispo
County,
Unincorporated
Areas
Middle
Branch
Huerhuero
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Morro Bay 12/18/1979
U.S.

Geological
Survey
IAA-H-17-75
and IAA- H-8-
76, Project
Order No.s 8
and 13
June 1977
Morro Bay, City of;
San Luis Obispo
County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 170
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Morro Creek 12/18/1979
U.S.

Geological
Survey
IAA-H-17-75
and IAA- H-8-
76, Project
Order No.s 8
and 13
June 1977 Morro Bay, City of
Morro Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Mountain
Springs
Creek
03/16/1981
George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
Newsome
Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Nipomo
Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Noname
Creek 12/18/1979 U.S.Geological Survey
IAA-H-17-75
and IAA- H-8-
76, Project
Order No.s 8
and 13
June 1977
Morro Bay, City of;
San Luis Obispo
County,
Unincorporated
Areas
North Fork
Los Berros
Creek
03/19/1984 USACE IAA-H-10- 77 January
1983
Arroyo Grande, City
of
North Fork
Paloma
Creek
07/20/1981
George S.

Nolte and
Associates
H-4722 December
1979 Atascadero, City of
Old Garden
Creek 10/1978
USACE, Los
Angeles
District,
California
IAA-H-74and
IAA-H- 16-75,
Project Order
No.s 13 and
22 June 1977 San Luis Obispo,
City of
Pacific
Ocean 05/16/2017 Baker AECOM
HSFEHQ- 09-
D-0368 07/20/2015
Grover Beach, City
of; Morro Bay, City
of; Pismo Beach,
City of; San Luis
Obispo, City of; San
Luis Obispo County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 171
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Paloma
Creek 07/20/1981
George S.

Nolte and
Associates
H-4722 December
1979
Atascadero, City of;
San Luis Obispo
County,
Unincorporated
Areas
Peachy
Canyon
Creek
03/16/1981
George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of; San Luis
Obispo County,
Unincorporated
Areas
Pismo Creek 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Pismo Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Pismo Creek 02/01/1984 USACE and
Tetra Tech IAA-H-10- 77 January 1983 Pismo Beach, City of Pismo Lake
Tributary 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
Pismo Beach, City
of; San Luis Obispo
County,
Unincorporated
Areas
Poorman
Creek 03/19/1984 USACE IAA-H-10- 77 January 1983
Arroyo Grande, City
of; San Luis Obispo
County,
Unincorporated
Areas
Prefumo
Canyon
Creek
10/1978
USACE, Los
Angeles
District,
California
IAA-H-74 and
IAA-H- 16-75,
Project Order
No.s 13 and
22 June 1977 San Luis Obispo,
City of
Prefumo
Creek 10/1978
USACE, Los
Angeles
District,
California
IAA-H-74 and
IAA-H- 16-75,
Project Order
No.s 13 and
22 June 1977
San Luis Obispo,
City of; San Luis
Obispo County,
Unincorporated
Areas
Salinas River 07/20/1981
George S.

Nolte and
Associates
H-4722 December
1979 Atascadero, City of
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 172
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Salinas River 03/16/1981
George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
Salinas River
Reach 1 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
March
2020
El Paso De Robles,
City of; San Luis
Obispo County,
Unincorporated
Areas
San Luis
Obispo
Creek
10/1978
USACE, Los
Angeles
District,
California
IAA-H-74 and
IAA-H- 16-75,
Project Order
No.s 13 and
22 June 1977 San Luis Obispo,
City of
San Luis
Obispo
Creek
07/05/1982
George S.

Nolte and
Associates
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
San Luis
Obispo
Creek South
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
December
2023
San Luis Obispo
County; San Luis
Obispo, City of
San Luis
Obispo
Creek South
06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
San Marcos
Creek 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Santa
Margarita
Creek
07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
Santa Rosa
Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Santa Rosa
Creek Split
Flow
06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 173
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
See Canyon
Creek 07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
See Canyon
Creek
(Lower
Reach)
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
See Canyon
Creek
(Upper
Reach)
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
South
Branch Toad
Creek
07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
South
Branch
Unnamed
Creek No. 1
03/16/1981
George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
South
Branch
Unnamed
Creek No. 2
03/16/1981
George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
South Fork
Paloma
Creek
07/20/1981
George S.

Nolte and
Associates
H-4722 December
1979 Atascadero, City of
Stenner
Creek 10/1978
USACE, Los
Angeles
District,
California
IAA-H-74 and
IAA-H- 16-75,
Project Order
No.s 13 and
22 June 1977
San Luis Obispo,
City of; San Luis
Obispo County,
Unincorporated
Areas
Tank Farm
Creek 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County; San Luis
Obispo, City of
Tar Spring
Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Tefft Road
Tributary 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 174
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Teft Road
Tributary
East Fork
06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Toad Creek
(Main and
North
Branches)
07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
Toro Creek 12/18/1979
U.S.

Geological
Survey
IAA-H-17-75
and IAA- H-8-
76, Project
Order No.s 8
and 13
June 1977
Morro Bay, City of;
San Luis Obispo
County,
Unincorporated
Areas
Trout Creek 07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
Unnamed
Creek (Alva
Paul Creek)
12/18/1979 U.S.Geologic
al Survey
IAA-H-17-75
and IAA- H-8-
76, Project
Order No.s 8
and 13
June 1977
Morro Bay, City of;
San Luis Obispo
County,
Unincorporated
Areas
Unnamed
Creek No. 1
03/16/1981 George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
Unnamed
Creek No. 2
03/16/1981 George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
Unnamed
Creek No. 3
03/16/1981 George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
Unnamed
Creek No. 4
03/16/1981 George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
Unnamed
Creek No. 5
03/16/1981 George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
Unnamed
Creek No. 6
03/16/1981 George S.

Nolte and
Associates
H-4722 December
1979
El Paso de Robles,
City of
Unnamed
Stream 07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 175
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Unnamed
Stream HU01 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Unnamed
Stream HU02 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Unnamed
Stream HU03
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Unnamed
Stream HU04 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Unnamed
Stream HU05
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Unnamed
Stream HU06
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Unnamed
Stream SO03 06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Upper
Branch
Huerhuero
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005 May 2020
San Luis Obispo
County,
Unincorporated
Areas
Vineyard
Canyon
Creek
06/06/2024
Strategic
Alliance for
Risk
Reduction
(STARR II)
HSFE60-15-
D-0005
October
2020
San Luis Obispo
County,
Unincorporated
Areas
Table 28: Summary of Contracted Studies Included in this FIS Report (continued) 176
Flooding
Source
FIS Report
Dated Contractor Number
Work
Completed
Date
Affected
Communities
Willow Creek 06/03/1991
USACE, Los
Angeles
District for
FEMA
EMW-89-E2994, Project
Order 8
December
1989
San Luis Obispo
County,
Unincorporated
Areas
Yerba Buena
Creek 07/05/1982
George S.

Nolte and
Associates
for FEMA
H-4722 December
1979
San Luis Obispo
County,
Unincorporated
Areas
* Data not available

7.2 Community Meetings
The dates of the community meetings held for this Flood Risk Project and previous Flood Risk Projects are shown in Table 29. These meetings may have previously been referred to by a variety of names (Community Coordination Officer (CCO), Scoping, Discovery, etc.), but all meetings represent opportunities for FEMA, community officials, study contractors, and other invited guests to discuss the planning for and results of the project. 177 Table 29: Community Meetings Community FIS Report Dated Date of Meeting Meeting Type Attended By Arroyo Grande, City of 06/06/2024 9/28/2018 Kick Off Meeting Representatives of Arroyo Grande, CA DWR, Caltrans District V, City of Grover Beach, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II, USACE 11/16/2021 Final CCO Representatives of CA DWR, City of Arroyo Grande, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II Atascadero, City of 07/20/1981 04/1978 Initial CCO FEMA, this community and the study contractor 01/26/1981 Final CCO FEMA, this community and the study contractor El Paso De Robles, City of 06/06/2024 9/28/2018 Kick Off Meeting Representatives of Arroyo Grande, CA DWR, Caltrans District V, City of Grover Beach, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II, USACE 11/16/2021 Final CCO Representatives of CA DWR, City of Arroyo Grande, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II Grover Beach, City of 06/06/2024 9/28/2018 Kick Off Meeting Representatives of Arroyo Grande, CA DWR, Caltrans District V, City of Grover Beach, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II, USACE 11/16/2021 Final CCO Representatives of CA DWR, City of Arroyo Grande, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II Morro Bay, City of 05/16/2017 12/02/2014 FRR Meeting FEMA, City of Grover Beach, City of Morro Bay, City of Pismo Beach, San Luis Obispo County, and BakerAECOM 12/07/2015 Final CCO FEMA, City of Grover Beach, City of Morro Bay, City of Pismo Beach, San Luis Obispo County, and BakerAECOM Table 29: Community Meetings (continued) 178 Community FIS Report Dated Date of Meeting Meeting Type Attended By Pismo Beach, City of 06/06/2024 9/28/2018 Kick Off Meeting Representatives of Arroyo Grande, CA DWR, Caltrans District V, City of Grover Beach, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II, USACE 6/24/2020 Flood Risk Review Representatives of CA DWR, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II 11/16/2021 Final CCO Representatives of CA DWR, City of Arroyo Grande, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II San Luis Obispo, City of 06/06/2024 9/28/2018 Kick Off Meeting Representatives of Arroyo Grande, CA DWR, Caltrans District V, City of Grover Beach, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II, USACE 6/24/2020 Flood Risk Review Representatives of CA DWR, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II 11/16/2021 Final CCO Representatives of CA DWR, City of Arroyo Grande, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II San Luis Obispo County, Unincorporated Areas 06/06/2024 9/28/2018 Kick Off Meeting Representatives of Arroyo Grande, CA DWR, Caltrans District V, City of Grover Beach, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II, USACE 6/24/2020 Flood Risk Review Representatives of CA DWR, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II 11/16/2021 Final CCO Representatives of CA DWR, City of Arroyo Grande, City of Paso Robles, City of Pismo Beach, City of San Luis Obispo, FEMA, San Luis Obispo County, STARR II 179
SECTION 8.0 – ADDITIONAL INFORMATION
Information concerning the pertinent data used in the preparation of this FIS Report can be obtained by submitting an order with any required payment to the FEMA Engineering Library. For more information on this process, see www.fema.gov. Table 30 is a list of the locations where FIRMs for San Luis Obispo County can be viewed.

Please note that the maps at these locations are for reference only and are not for distribution. Also, please note that only the maps for the community listed in the table are available at that particular repository. A user may need to visit another repository to view maps from an adjacent community.

Table 30: Map Repositories
Community Address City State Zip Code
Arroyo Grande, City of City Hall
300 East Branch Street Arroyo Grande CA 93420
Atascadero, City of City Hall
6500 Palma Avenue Atascadero CA 93422
El Paso de Robles, City
of
City Hall
1000 Spring Street Paso Robles CA 93446
Grover Beach, City of City Hall
154 South Eighth Street Grover Beach CA 93433
Morro Bay, City of City Hall
595 Harbor Street Morro Bay CA 93442
Pismo Beach, City of City Hall
760 Mattie Road Pismo Beach CA 93449
San Luis Obispo, City
of
City Hall
990 Palm Street
San Luis
Obispo CA 93401
San Luis Obispo,
Unincorporated Areas
County Government Center
1055 Monterey Street Room
D-430
San Luis
Obispo CA 93408
The National Flood Hazard Layer (NFHL) dataset is a compilation of effective FIRM Databases and LOMCs. Together they create a GIS data layer for a State or Territory.

The NFHL is updated as studies become effective and extracts are made available to the public monthly. NFHL data can be viewed or ordered from the website shown in Table 31.

Table 31 contains useful contact information regarding the FIS Report, the FIRM, and other relevant flood hazard and GIS data. In addition, information about the State NFIP Coordinator and GIS Coordinator is shown in this table. At the request of FEMA, each Governor has designated an agency of State or territorial government to coordinate that State's or territory's NFIP activities. These agencies often assist communities in developing and adopting necessary floodplain management measures. State GIS Coordinators are knowledgeable about the availability and location of State and local GIS data in their state.
180
Table 31: Additional Information
FEMA and the NFIP
FEMA and FEMA
Engineering Library website
www.fema.gov/national-flood-insurance-program-floodhazard-mapping/engineering-library NFIP website www.fema.gov/national-flood-insurance-program NFHL Dataset msc.fema.gov
FEMA Region IX FEMA Regional Center IX
1111 Broadway, Suite 1200
Oakland, CA 94607
510-627-7181
Other Federal Agencies
USGS website www.usgs.gov
Hydraulic Engineering Center
website
www.hec.usace.army.mil
State Agencies and Organizations
State NFIP Coordinator Kelly Soule
State NFIP Coordinator
Chief, Community Assistance & Risk Awareness Branch
Office of Floodplain Management
Division of Flood Management
CA Department of Water Resources
3464 El Camino Ave, Suite 200
Sacramento, California 95821
State Floodplain Manager Mike Mierzwa
State Floodplain Manager
CA Department of Water Resources
3464 El Camino Ave, Suite 200
Sacramento, California 95821
State GIS Coordinator David Harris
Agency Information Officer
California Natural Resources Agency
1416 Ninth Street, Room 1311
Sacramento, CA 95814
916-445-5088
[email protected]
SECTION 9.0 – BIBLIOGRAPHY AND REFERENCES
Table 32 includes sources used in the preparation of and cited in this FIS Report as well as additional studies that have been conducted in the study area. 181 Table 32: Bibliography and References Citation in this FIS Publisher/ Issuer Publication Title, “Article,” Volume, Number, etc. Author/Editor Place of Date/ Date of Issuance Link Avila, 2022 Federal Emergency Management Agency Floodplain Delineation Study of San Luis Obispo Creek Avila and Associates 12/13/2022 CASBOE, 2015 County of San Luis Obispo GIS BOE City Boundaries California State Board of Equalization San Luis Obispo, CA 3/6/2015 https://opendata.slocounty.ca.gov/ CDPR, 2018 California Department of Parks and Recreation California State Parks System California Department of Parks and Recreation Sacramento, CA 2018 https://www.parks.ca.gov/?page_id =862/ CSC, 2011 Coastal Services Center Coastal California Digital Imagery NOAA Oakland, CA February 2011 https://coast.noaa.gov/htdata/raster 1/imagery/CoastalCA_2009 _1168/ CSC, 2011 Coastal Services Center Coastal California LiDAR and Digital Imagery COASTAL SERVICES CENTER Oakland, CA 5/16/2011 CSMP, 2011 Hydrographic survey data bathymetry; 2 – 10 DEM Fugro EarthData, Inc. 2005-2011 https://seafloor.csumb.edu/csmp/ csmp.html Divoky, D., 2007 Supplementary WHAFIS Documentation: WHAFIS 4.0, A Revision of FEMA’s WHAFIS 3.0 Program Divoky, D. Atlanta, GA 2007 FEMA, 1988 Federal Emergency Management Agency Wave Height Analysis for Flood Insurance Studies (Technical Documentation for WHAFIS Program Version 3.0) D.C. 1988 https://www.fema.gov/media- library/assets/documents/11563/ Table 32: Bibliography and References (continued) 182 Citation in this FIS Publisher/ Issuer Publication Title, “Article,” Volume, Number, etc. Author/Editor Place of Date/ Date of Issuance Link FEMA, 2005 Federal Emergency Management Agency Final Draft Guidelines for Coastal Flood Hazard Analysis and Mapping for the Pacific Coast of the United States 2005 FEMA, 2008 Federal Emergency Management Agency San Luis Obispo County, California Effective Digital Flood Insurance Rate Map Federal Emergency Management Agency Washington, D.C. 8/28/2008 FEMA, 2008a Federal Emergency Management Agency San Luis Obispo County, California Digital Flood Insurance Rate Map Federal Emergency Management Agency Washington, D.C. 11/10/2008 FEMA, 2008b Federal Emergency Management Agency San Luis Obispo County, California Digital Flood Insurance Rate Map Federal Emergency Management Agency Washington, D.C. 11/10/2008 FEMA, 2008c Federal Emergency Management Agency MAPIX Task Order 29 Santa Maria River Restudy Federal Emergency Management Agency Washington, D.C. 11/10/2008 FEMA, 2011 Federal Emergency Management Agency Letter of Map Revision, Case number 10-09-3119P, San Luis Obispo County Unincorporated Areas, California Federal Emergency Management Agency Washington, D.C. 12/21/2011 https://msc.fema.gov/ FEMA, 2012 Federal Emergency Management Agency Flood Insurance Study, San Luis Obispo County and Incorporated Areas November 2012 https://msc.fema.gov/ Table 32: Bibliography and References (continued) 183 Citation in this FIS Publisher/ Issuer Publication Title, “Article,” Volume, Number, etc. Author/Editor Place of Date/ Date of Issuance Link FEMA, 2017 Federal Emergency Management Agency San Luis Obispo County, California Coastal Analysis and Mapping Project/Open Pacific Coast Study Federal Emergency Management Agency Washington, D.C. 5/16/2017 https://msc.fema.gov/ FEMA, 2018 Federal Emergency Management Agency LOMR Study Area Federal Emergency Management Agency Washington, D.C. 8/28/2018 https://msc.fema.gov/ FEMA, 2019 Federal Emergency Management Agency LOMR Study Area Federal Emergency Management Agency Washington, D.C. 8/28/2018 https://msc.fema.gov/ FEMA, 2019a Federal Emergency Management Agency LOMR Study Area Federal Emergency Management Agency Washington, D.C. 7/3/2019 https://msc.fema.gov/ FEMA, 2021 Federal Emergency Management Agency LOMR Study Area Federal Emergency Management Agency Washington, D.C. 10/7/2020 https://msc.fema.gov/ FEMA, 2021a Federal Emergency Management Agency LOMR Study Area Federal Emergency Management Agency Washington, D.C. 5/21/2021 https://msc.fema.gov/ FEMA, 2023 Federal Emergency Management Agency Five Cities Center Flood Assessment LOMR Federal Emergency Management Agency 10/4/2023 https://msc.fema.gov/ Table 32: Bibliography and References (continued) 184 Citation in this FIS Publisher/ Issuer Publication Title, “Article,” Volume, Number, etc. Author/Editor Place of Date/ Date of Issuance Link NOAA National Geophysical Data Center Tsunami Inundation Bathymetry; 10 – 30 DEM National Oceanic and Atmospheric Administration https://www.ngdc.noaa.gov/mgg/ inundation/tsunami/inundation.ht ml NOAA, 2015 NOAA NOAA Tides and Currents NOAA Washington, D.C. 9/16/2015 https://tidesandcurrents.noaa.gov / Penfield & Smith, 2007 Survey Report of Stream Surveying in Support of Santa Maria River Restudy W.O. 10358.02 Penfield & Smith 2007 Schaaf & Wheeler, 2023 Federal Emergency Management Agency East Fork Flood Analysis Schaaf & Wheeler San Francisco, CA March 2023 SLO, 2017 County of San Luis Obispo GIS County of San Luis Obispo Transportation Lines County of San Luis Obispo GIS San Luis Obispo, CA 12/27/2017 https://opendata.slocounty.ca.gov / SLO, 2020 County of San Luis Obispo GIS County Boundary County of San Luis Obispo GIS San Luis Obispo, CA 8/27/2020 https://opendata.slocounty.ca.gov / STARRII, 2024a Federal Emergency Management Agency San Luis Obispo County PMR Areas: Huerhuero Creek, Meadow Creek, Salinas River and San Luis Obispo Creek STARRII Austin, TX 6/6/2024 https://hazards.fema.gov/femapor tal/wps/myportal/ STARRII, 2024b Federal Emergency Management Agency Central Coastal Watershed and Salinas Watershed, California Base Level Engineering STARRII 6/6/2024 Table 32: Bibliography and References (continued) 185 Citation in this FIS Publisher/ Issuer Publication Title, “Article,” Volume, Number, etc. Author/Editor Place of Date/ Date of Issuance Link USACE, 1992 U.S. Army Corps of Engineers Automated Coastal Engineering System, version 1.07, Coastal Engineering Research Center, Department of the Army, Waterways Experiment Station Leenknecht, David, Andre Szuwalski, and Ann R. Sherlock 1992 USACE, 1984 U.S. Army Corps of Engineers Shore Protection Manual, Volumes 1-3, 532 pp. Washington, D.C. 1984 USACE, 1973 U.S. Army Corps of Engineers, Hydrologic Engineering Center Computer Program HEC-2, Water Surface Profiles Davis, California October 1973 USACE, January 1973 U.S. Army Corps of Engineers HEC-1 Flood Hydrograph Package Davis, California January 1973 USACE, 1971 U.S. Army Corps of Engineers, South Pacific Division National Shoreline Study: California Regional Inventory August 1971 USDA, 2005 U.S. Department of Agriculture Farm Service Agency National Agriculture Imagery Program U.S. Department of Agriculture Farm Service Agency Washington, D.C. 2005 USDA, 2012 US Department of Agriculture Farm Service Agency Aerial Photography Field Office USDA-FSA-APFO NAIP MrSID Mosaic USDA/FSA - Aerial Photography Field Office Salt Lake City, Utah 2/21/2012 Table 32: Bibliography and References (continued) 186 Citation in this FIS Publisher/ Issuer Publication Title, “Article,” Volume, Number, etc. Author/Editor Place of Date/ Date of Issuance Link USDA, 2016 United States Department of Agriculture Farm Service Agency National Agriculture Imagery Program United States Department of Agriculture Farm Service Agency Washington, D.C. 10/4/2016 https://www.fsa.usda.gov/ USDA, 2020 USDA Forest Service Administrative Forest USDA Forest Service Automated Lands Program (ALP) Salt Lake City, UT 8/24/2020 https://data.fs.usda.gov/geodata/ edw/datasets.php USDC, 2013 U.S. Department of Commerce, U.S. Census Bureau, Geography Division TIGER/Line Files Transportation Layer U.S. Department of Commerce Washington, D.C. 2013 U.S. Department of the Interior, 1976 U.S. Department of the Interior, Geological Survey Open-File Report 76- 499, User’s Manual for Computer Program E- 431: Computer Applications for Step- Backwater and Floodway Analysis J.O. Sherman 1976 U.S. Department of the Interior, 1977 U.S. Department of the Interior, Geological Survey Water Resources Investigation 77-21, Magnitude and Frequency of Floods in California June 1977 U.S. Department of the Interior, 1977 (a) U.S. Department of the Interior, Geological Survey Water Resources Investigation 77-21, Magnitude and Frequency of Floods in California: Menlo Park, California A.O. Waananen and J. R. Crippen June 1977 U.S. Department of the Interior, 1978 U.S. Department of the Interior, Geological Survey Unpublished Records October 25, 1978 Table 32: Bibliography and References (continued) 187 Citation in this FIS Publisher/ Issuer Publication Title, “Article,” Volume, Number, etc. Author/Editor Place of Date/ Date of Issuance Link USGS, 1993 California Spatial Information Library San Luis Obispo County PLSS data, State and Federal land boundaries U.S. Gelogical Survey Reston, VA November 1993 USGS, 1994 U. S. Geological Survey Digital Orthophoto Quadrangles, contour scale 1:12,000, photography dated 1994 or later NP 1994 USGS, 2006 U. S. Geological Survey 2001 California Hydrologic Data Report– 11140000 Sisquoc River near Garey, CA. Downloaded October 2006 https://ca.water.usgs/archive/wat erdata/2001/11140000.html USGS, 2010 United States Geological Survey Airborne Topographic LiDAR data, California Open Pacific Coast, Southern portion of the City and County of San Francisco Fugro EarthData, Inc. 2009-2011 USGS, 2018 United States Geological Survey National Hydrography Dataset United States Geological Survey Washington, D.C. 8/21/2018 https://www.usgs.gov/ U.S. Water Resources Council, 1976 U.S. Water Resources Council, Hydrology Committee Bulletin 17A “Guidelines for Determining Flood Flow Frequency” March 1976 Van der Meer, J.W., 2002 Wave Run-up and Overtopping at Dikes. Technical Report, Technical Advisory Committee for Water Retaining Structures (TAW) Delft, the Netherlands 2002 Table 32: Bibliography and References (continued) 188 Citation in this FIS Publisher/ Issuer Publication Title, “Article,” Volume, Number, etc. Author/Editor Place of Date/ Date of Issuance Link Wesbter, 2021 Steven B. Webster Avila Ranch Tract 3089 - Phase 1 Certified Topographical Map Steven B. Webster 6/24/2021 VOLUME OF 4

AND INCORPORATED AREAS

SAN LUIS OBISPO COUNTY,
UNINCORPORATED AREAS 060304
REVISED:

JUNE 6, 2024

FLOOD INSURANCE STUDY NUMBER
06079CV00 D
Version Number 2.6.3.6

SAN LUIS OBISPO

COUNTY, CALIFORNIA
i

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 6 SECTION 2.0 – FLOODPLAIN MANAGEMENT APPLICATIONS 17

2.1 Floodplain Boundaries 17

2.2 Floodways 34

2.3 Base Flood Elevations 35

2.4 Non-Encroachment Zones 35

2.5 Coastal Flood Hazard Areas 36

2.5.1 Water Elevations and the Effects of Waves 36

2.5.2 Floodplain Boundaries and BFEs for Coastal Areas 37

2.5.3 Coastal High Hazard Areas 38

2.5.4 Limit of Moderate Wave Action 39
SECTION 3.0 – INSURANCE APPLICATIONS 40

3.1 National Flood Insurance Program Insurance Zones 40 SECTION 4.0 – AREA STUDIED 40

4.1 Basin Description 40

4.2 Principal Flood Problems 41

4.3 Non-Levee Flood Protection Measures 43

4.4 Levees 46
SECTION 5.0 – ENGINEERING METHODS 49

5.1 Hydrologic Analyses 49

5.2 Hydraulic Analyses 62
Volume 2
SECTION 5.0 – ENGINEERING METHODS

5.3 Coastal Analyses 98

5.3.1 Total Stillwater Elevations 99

5.3.2 Waves 101

5.3.3 Coastal Erosion 102

5.3.4 Wave Hazard Analyses 102

5.4 Alluvial Fan Analyses 116
SECTION 6.0 – MAPPING METHODS 116
ii

6.1 Vertical and Horizontal Control 116

6.2 Base Map 118

6.3 Floodplain and Floodway Delineation 119

6.4 Coastal Flood Hazard Mapping 158

6.5 FIRM Revisions 161

6.5.1 Letters of Map Amendment 162

6.5.2 Letters of Map Revision Based on Fill 162

6.5.3 Letters of Map Revision 162

6.5.4 Physical Map Revisions 163

6.5.5 Contracted Restudies 163

6.5.6 Community Map History 164
SECTION 7.0 – CONTRACTED STUDIES AND COMMUNITY COORDINATION 165

7.1 Contracted Studies 165

ELEVATIONS DOWNSTREAM OF

THIS POINT CONTROLLED BY

THE PACIFIC OCEAN

SOUTHBOUND

CAYUCOS DRIVE
ELEVATION IN FEET (NAVD 88)

AND INCORPORATED AREAS
FEDERAL EMERGENCY MANAGEMENT AGENCY FLOOD PROFILES LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED CROSS SECTION LOCATION 2 P STREAM DISTANCE IN FEET ABOVE PACIFIC OCEAN

SAN LUIS OBISPO COUNTY, CA

LITTLE CAYUCOS CREEK

ASH AVENUE
STATE HIGHWAY 1

LIMIT OF DETAILED STUDY

OCEAN AVENUE
STATE HIGHWAY 1

NORTHBOUND

760 750 740 730 720 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 ELEVATION IN FEET (NAVD) P LEGEND 0.2% ANNUAL CHANCE FLOOD* 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD* 10% ANNUAL CHANCE FLOOD* STREAM BED 780 770 710 700 5500 6000 6500790 780 770 760 750 740 730 720 CROSS SECTION LOCATION STREAM DISTANCE IN FEET ABOVE CONVERGENCE WITH TOAD CREEK (MAIN AND NORTH BRANCH)

CONVERGENCE WITH TOAD CREEK
(MAIN AND NORTH BRANCH) 790 *DATA NOT AVAILABLE
ELEVATION IN FEET (NAVD88)

P STREAM DISTANCE IN FEET ABOVE PACIFIC OCEAN

SAN LUIS OBISPO COUNTY, CA

MORRO CREEK
ON RAMP STATE HIGWAY 1
STATE HIGHWAY 1
OFF RAMP STATE HIGHWAY 1 MAIN STREET COASTAL FLOOD EFFECTS FROM PACIFIC OCEAN SEE FLOOD INSURANCE RATE MAP FOR BASE FLOOD ELEVATIONS AND COASTAL TRANSECT DATA TABLE FOR STILLWATER ELEVATIONS THE 10% AND 2% ANNUAL CHANCE FLOOD PROFILES ARE TOO CLOSE TO THE 1% ANNUAL CHANCE ELEVATION TO BE SHOWN SEPARATELY

SAN LUIS OBISPO COUNTY, CA P

NIPOMO CREEK

PRIVATE ROAD
FRONTAGE ROAD 101 SOUTHBOUND

PRIVATE ROAD

LIMIT OF DETAILED STUDY

LIMIT OF DETAILED STUDY
U.S. HIGHWAY
101 NORTHBOUND
U.S. HIGHWAY STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SANTA MARIA RIVER ELEVATION IN FEET (NGVD29)1
1 This profile is provided in NGVD29, for use with the following effective FIRM panels not included in this map revision. (06079C1639F, 06079C1902F, 06079C1906F)

VOLUME OF 4

AND INCORPORATED AREAS

SAN LUIS OBISPO COUNTY,
UNINCORPORATED AREAS 060304
REVISED:

JUNE 6, 2024

FLOOD INSURANCE STUDY NUMBER
06079CV00 D
Version Number 2.6.3.6

SAN LUIS OBISPO

COUNTY, CALIFORNIA
i

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 6 SECTION 2.0 – FLOODPLAIN MANAGEMENT APPLICATIONS 17

2.1 Floodplain Boundaries 17

2.2 Floodways 34

2.3 Base Flood Elevations 35

2.4 Non-Encroachment Zones 35

2.5 Coastal Flood Hazard Areas 36

2.5.1 Water Elevations and the Effects of Waves 36

2.5.2 Floodplain Boundaries and BFEs for Coastal Areas 37

2.5.3 Coastal High Hazard Areas 38

2.5.4 Limit of Moderate Wave Action 39
SECTION 3.0 – INSURANCE APPLICATIONS 40

3.1 National Flood Insurance Program Insurance Zones 40 SECTION 4.0 – AREA STUDIED 40

4.1 Basin Description 40

4.2 Principal Flood Problems 41

4.3 Non-Levee Flood Protection Measures 43

4.4 Levees 46
SECTION 5.0 – ENGINEERING METHODS 49

5.1 Hydrologic Analyses 49

5.2 Hydraulic Analyses 62
Volume 2
SECTION 5.0 – ENGINEERING METHODS

5.3 Coastal Analyses 98

5.3.1 Total Stillwater Elevations 99

5.3.2 Waves 101

5.3.3 Coastal Erosion 102

5.3.4 Wave Hazard Analyses 102

5.4 Alluvial Fan Analyses 116
SECTION 6.0 – MAPPING METHODS 116
ii

6.1 Vertical and Horizontal Control 116

6.2 Base Map 118

6.3 Floodplain and Floodway Delineation 119

6.4 Coastal Flood Hazard Mapping 158

6.5 FIRM Revisions 161

6.5.1 Letters of Map Amendment 162

6.5.2 Letters of Map Revision Based on Fill 162

6.5.3 Letters of Map Revision 162

6.5.4 Physical Map Revisions 163

6.5.5 Contracted Restudies 163

6.5.6 Community Map History 164
SECTION 7.0 – CONTRACTED STUDIES AND COMMUNITY COORDINATION 165

7.1 Contracted Studies 165

ELEVATION IN FEET (NAVD 88)

P STREAM DISTANCE IN FEET ABOVE PACIFIC OCEAN

SAN LUIS OBISPO COUNTY, CA

SAN LUIS OBISPO CREEK

AVILA BEACH OF THIS POINT

FOOTBRIDGE

ELEVATIONS DOWNSTREAM

CONTROLLED BY

THE PACIFIC OCEAN
DRIVE

TOAD CREEK (MAIN AND NORTH BRANCH)

FLOOD PROFILES P
P
ELEVATION IN FEET (NAVD88)

SAN LUIS OBISPO COUNTY, CA

TORO CREEK

PACIFIC OCEAN
STATE HIGHWAY 1

LIMIT OF STUDY COASTAL FLOOD EFFECTS FROM PACIFIC OCEAN SEE FLOOD INSURANCE RATE MAP FOR BASE FLOOD ELEVATIONS AND COASTAL TRANSECT DATA TABLE FOR STILLWATER ELEVATIONS

ELEVATION IN FEET (NAVD88)

P STREAM DISTANCE IN FEET FROM STATE BEACH

SAN LUIS OBISPO COUNTY, CA

UNNAMED CREEK (ALVA PAUL CREEK)

STATE BEACH

SANDALWOOD AVENUE

ELEVATIONS DOWNSTREAM

CONTROLLED BY TIDAL FLOODING

FROM PACIFIC OCEAN TIDAL FLOOD EFFECTS FROM PACIFIC OCEAN SEE FLOOD INSURANCE RATE MAP FOR BASE FLOOD ELEVATIONS AND COASTAL TRANSECT DATA TABLE FOR STILLWATER ELEVATIONS

Grover Beach City CouncilMay 28, 2024

Grover Beach City Council
May 28, 2024