Transcript Neuse River Basin Plan Presentation

North Carolina
Neuse River Basin Plan
Final Scoping Meetings
April 23, 24, and 25, 2001
North Carolina
Cooperating Technical State
Flood Mapping Program
Overview
Purposes of the NFIP
1. Make flood insurance
available
2. Identify floodplain
areas and flood risk zones
3. Provide framework for a community’s
floodplain management ordinances
Importance of Updated Flood
Hazard Information

With up-to-date flood hazard data:

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Map users can make prudent siting,
design, and flood insurance purchase
decisions
Communities can administer sound
floodplain management programs
North Carolina’s Flood
Mapping Program

Program established to implement the
Cooperating Technical State (CTS)
Partnership with FEMA, signed
September 15, 2000

Ownership and responsibility for Flood
Insurance Rate Maps (FIRMs) delegated
to State
Organization of the CTS
Flood Mapping Program
OSBPM
John Dorman,
Program Director/Chair
CTS
Committee
NC Center for
Geographic Information
and Analysis
NC
Geodetic Survey
NC Division of
Emergency
Management
Federal Emergency
Management Agency
Rodger Durham,
Abdul Rahmani,
Program Manager
Project Manager
Mapping
Coordination
Contractor
Dewberry &
Davis LLC
State Floodplain
Mapping
Contractor
Greenhorne &
O’Mara, Inc.
State Floodplain
Mapping
Contractor
Watershed
Concepts, Inc.
Why North Carolina Is
Undertaking This Project

State’s vulnerability to hurricanes
and flooding

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
14 federally declared disasters since 1989
Hurricane Floyd damages = $3.5 billion
4,117 uninsured/under-insured homes
destroyed as result of Hurricane Floyd
Accurate, up-to-date flood hazard
information crucial to protect lives
and property
Why North Carolina Is
Undertaking This Project

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Hurricane Floyd revealed flood hazard data
and map limitations
Age of North Carolina FIRMS

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
FEMA’s mapping budget is finite


55% at least 10 years old
75% at least 5 years old
North Carolina receives only one updated
flood study for one county per year
Many counties and communities lack
resources to take on this responsibility
Benefits of North
Carolina’s CTS Program




Current, accurate data for sound siting
and design decisions
Better floodplain management to
reduce long-term flood losses
Updated data to alert at-risk property
owners of the need for flood insurance
Faster, less expensive FIRM updates
Program Components

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Developing flood hazard studies through
community mapping needs analysis (Scoping)
Acquiring high-resolution topographic data and
accurate Digital Elevation Models (DEMs)
Conducting engineering studies
Generating countywide digital FIRMs (DFIRMs)
Designing and implementing state-of-the-art,
dynamic IT infrastructure
Supporting real-time flood forecasting and
inundation mapping capability
Digital FIRMs
+
Base
=
Topography
+
Flood Data
Digital
FIRM
Digital FIRMs



Digital FIRMs will be produced in a
countywide format
Will depict all flood hazard data
FIRM panels will be consistent with the
State land records 10,000’ by 10,000’
tiling scheme
Community Review and
Due Process

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Preliminary FIRMs provided when the
Neuse River Basin Study is complete
90-day appeal period
Preliminary Countywide FIRMs provided
when adjacent basin studies are complete
All appeals evaluated and resolved
Final Effective FIRMs provided and made
available by the State on its Information
Management System
Additional Benefits of
the CTS Program

Digital format to allow:

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More efficient, precise flood risk
determinations
Geographic Information System (GIS)
analysis and planning
Online access 24 hours a day
DEMs will be useful for almost any
engineering or planning application
Neuse River Basin



Originates in north central Piedmont region
of North Carolina in Person and Orange
Counties, extends southeast through the
Coastal Plain region, and eventually flows
into Pamlico Sound
Third largest river basin in North Carolina,
encompassing an area of approximately
6,200 square miles
Encompasses all or parts of 23 counties
and 78 municipalities
Scoping Phase for
Neuse River Basin
The Scoping Phase determines:
 What areas are floodprone and need
flood hazard data developed
 Determine appropriate technical method
for developing up-to-date flood hazard
data and establish priority level
 How flood hazard data will be presented
on FIRMs
SCOPING
PRODUCTION
Step 1
Step 2
Step 3
Step 4
Step 5
Initial Research
and Community
Coordination
Initial
Scoping
Meeting
Draft
Basin
Plans
Final
Scoping
Meeting
Final Basin
Plans
Initial
Scoping
Meetings
Develop
Draft
Basin
Plans
Final
Scoping
Meetings
State
Kickoff
Meeting with
County/Local
Floodplain
Administrators
Questionnaire
State
Mapping
Needs
Assessment
NC
Scoping
Database
Generate
Initial
Scoping
Package
Finalize
Basin
Plans
FEMA
Effective
FIS & FIRM
Research
FEMA
Evaluate
Post-Floyd
Data
Process for Scoping Six River Basins
in Eastern North Carolina
Prepare
Delivery
Orders
& CTC
Mapping
Activity
Agreements
& Update
CTS
Mapping
Agreement
Analysis
and
Mapping
Step 4 — Final Scoping Meeting
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THIS IS WHERE WE ARE TODAY!
All impacted counties and communities invited
Three separate Final Scoping Meetings:
 April 23rd – Raleigh, NC
 April 24th – Goldsboro, NC
 April 25th – New Bern, NC
Draft Neuse River Basin plan presented
Provides final opportunity for input
Step 5 — Final Basin Plan
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Draft Basin Plan may be revised following
the Final Scoping Meeting
Watershed Concepts, the State’s Floodplain
Mapping Contractor for the Neuse River
Basin, will develop proposals for the State
Neuse River Basin Plan will be finalized and
notification sent to impacted counties and
communities
Production phase will then begin
North Carolina
Neuse River Basin Meeting
QUESTIONS ON THE
SCOPING PHASE
???
Draft Neuse
River Basin Plan

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Summarizes scoping phase
Outlines how base maps and
topography will be acquired
Proposes engineering methods by
which each flooding source reach will
be studied
Describes the process and schedule for
completing the map production
Detailed Study — Riverine

This method requires the following:


Digital Elevation Data
Field Surveys

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Channel bathymetry
Bridge/culvert opening geometry
Channel and floodplain characteristics
Detailed Hydrologic and Hydraulic Analyses

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10%, 2%, 1%, and 0.2% annual chance flood
elevations and boundaries identified (Zone AE)
Floodways delineated
Riverine Areas to be
Studied in Detail
County
Durham
Franklin/
Wake
Granville
Flooding Sources
Portions of: Crooked Creek, Crooked Creek Tributary 1, Ellerbe Creek, Eno
River, Eno River Tributaries A, Z, and 3, Goose Creek, Goose Creek
Tributary A, Sevenmile Creek, South Ellerbe Creek, South Ellerbe Creek
Tributary, Warren Creek, Warren Creek Tributaries A and B, Unnamed
Tributary to Warren Creek
Portions of: Moccasin Creek
Portions of: Holman Creek, Holman Creek Tributaries A and B, Picture
Creek
Approx.
Length
(miles)
47.1
9.1
8.8
Greene/Pitt/
Lenoir
Portions of: Contentnea Creek
Johnston
Portions of: Little River
29.7
Jones
Portions of: Crooked Run, Trent River
11.0
Lenoir
Portions of: Adkin Branch, Neuse River
45.1
Lenoir/
Wayne
Portions of: Bear Creek
16.2
12.0
Riverine Areas to be
Studied in Detail
County
Flooding Sources
Approx.
Length
(miles)
Orange
Portions of: Cates Creek, Unnamed Tributary to Cates Creek, McGowan
Creek, Strouds Creek
14.4
Person
Portions of: Unnamed Tributary to North Flat River, Unnamed Tributaries
A, B, and C
6.4
Pitt
Portions of: Fork Swamp, Unnamed Tributaries A, B, and C, Swift Creek
22.6
Wake
Portions of: Bagwell Branch, Beaverdam Creek, Big Branch, Briar Creek,
Little River, Marsh Creek, New Hope Tributary, Perry Creek, Richland
Creek, Unnamed Tributary to Richland Creek, Swift Creek, Walnut Creek,
Basal Creek
73.9
Wayne
Portions of: Billy Bud Creek, Mill Creek North, Unnamed Tributaries A, B,
and C, Unnamed Tributary D, Unnamed Tributary E, Richland Creek,
Stoney Creek
22.3
Wilson
Portions of: Contentnea Creek, Headwaters of Hominy Swamp, Hominy
Swamp
34.6
Total
353.2
(cont’d)
Detailed Study — Coastal
This method produces the following:

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Floodplain mapping for areas along
open coast and embayments
Designations as Zones AE or VE
Redelineation

This method requires the following:


Digital Elevation Data
Effective FIS flood elevations
Proposed for all areas currently shown
on effective FIRM as Zone A1-30/AE or
V1-30/VE and not being restudied
Approximate Study

This method requires the following:

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Digital Elevation Data
Delineation of 1% annual chance floodplain
boundaries using approximate methods
May include collection and use of fieldcollected topographic data or bridge/culvert
data if plans are not readily available
Proposed for all areas currently
shown on effective FIRM as Zone A
and not being restudied in detail.
Use of Effective
Information

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This method involves no new analyses or
floodplain mapping
Effective FIS and FIRM data are digitized and
fitted to updated base map
This method is not anticipated to be
used for any communities in the
Neuse River Basin.
Going Beyond the
Minimum

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Communities are encourgaged to
manage floodplain development
according to standards that are more
stringent than FEMA minimums.
Benefits of adopting higher standards:


Reduced risk to lives and property, and
Lowered flood insurance premiums,
including possible Community Rating
System discounts.
Community Mapping
Options

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Community-adopted higher standards
can be supported by optional map
features shown digitally in a separate
GIS layer, or possibly printed on the
FIRM, or both.
Communities can have “customized”
flood hazard data generated for their
area through the NC Flood Mapping
Program.
Community Mapping
Options (continued)

Customized flood hazard data options:


1% annual chance floodplains and
elevations based on future land use
conditions (in addition to existing
conditions data),
Wider floodways based on a reduced
surcharge value (i.e., less than the 1-foot
FEMA maximum), and
Community Mapping
Options (continued)

Flood hazard data options: (continued)

Areas within a community-adopted
“freeboard contours” (i.e., areas that
would be inundated if floodwaters
reached the freeboard level)
Guidance for
Communities

The State will provide guidance to
communties on:
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Selecting higher standards options that
meet community needs,
Data the communities must provide (land
use plan, etc.),
Potential community cost sharing to cover
increased mapping costs,
Higher Standards
(continued)

State guidance: (continued)
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Model Flood Hazard Damage Prevention
ordinances that reflect enhanced
floodplain management standards, and
Outreach programs for citizens and
businesses affected by newly mapped
flood hazard areas or updated
ordinances.
Schedule for FIRM
Production
County
FIRM
Panels in
Neuse Basin
Projected
Preliminary
Date for Neuse
Portion
Other Basin(s)/
Projected Preliminary Date
Carteret
36
August 2002
White Oak (August 2001)
Craven
109
August 2002
Durham
43
February 2002
Cape Fear (February 2002)
Franklin
9
August 2002
Tar-Pamlico (August 2001)
Granville
24
February 2002
Greene
31
August 2002
N/A
Johnston
111
February 2002
Cape Fear (February 2002)
Jones
29
August 2002
White Oak (August 2001)
Lenoir
59
August 2002
Cape Fear (August 2002)
Nash
4
August 2002
Tar-Pamlico (August 2001)
Tar-Pamlico (August 2001)
White Oak (August 2001)
Tar-Pamlico (August 2001)
Roanoke (Est. 2003)
Schedule for FIRM
Production
County
FIRM
Panels in
Neuse Basin
Projected
Preliminary Date
for Neuse Portion
Orange
43
February 2002
Pamlico
25
August 2002
Person
10
February 2002
Pitt
37
August 2002
Tar-Pamlico (August 2001)
Wake
181
February 2002
Cape Fear (February 2002)
Wayne
69
August 2002
Cape Fear (August 2002)
Wilson
59
August 2002
Tar-Pamlico (August 2001)
Other Basin(s)/
Projected Preliminary Date
Cape Fear (February 2002)
Roanoke (Est. 2003)
Tar-Pamlico (August 2001)
Tar-Pamlico (February 2002)
Roanoke (Est. 2003)
(cont’d)
North Carolina
Neuse River Basin Meeting
QUESTIONS ON THE
DRAFT BASIN PLAN
???
North Carolina
Flood Mapping Program
For More Information
Web Site: www.ncfloodmaps.com
FEMA Map Assistance: 1-877-336-2627
State POC: Rodger Durham (919) 715-2127