HAZARD MITIGATION IN HISTORIC DISTRICTS

Louisette L. Scott AICP, CFMDirector, Dept. Planning & DevelopmentMandeville, LAJanuary 31, 2018

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Mandeville, LA

Mandeville is Located on the northshoreof Lake Pontchartrain across from New Orleans.

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“Bay” Pontchartrain3

Mandeville

1851-1860 – active years right after the founding of Mandeville – 6 hurricanes stronger than Cat. 3

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Many of our historic homes were built elevated, especially in era after early hurricanes5

Mandeville has a Historic context for elevated homes.note proportion: 2/3 1/36

Lake Pontchartrain Causeway 1956/1969 resulted in tremendous growth – fastest growing community in the 80’s for~10 years

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With opening of causeway….

Many new residents from New Orleans. New Orleans is protected by a levee system –

Mandeville gravity drainage Many folks did not realize the impacts/flooding

from the Lake Occurred in late 50’s-70’s when post WWII homes

were built – slab on grade Many did not completely understand the

environment they lived in.

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A day in the life by the lake –know your environment

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NOAA - National Oceanic & Atmospheric Administration

Hurricane Track ~100 years10

Hurricane Katrina – the new normal11

Past just to east of Mandeville (NOLA)better situation for LA not for MS (SE wind)12

Hurricane Isaac (2012)13

Eye just to the west of Mandeville – scenario causes more severe impact for storm surge.

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Old Mandeville Shoreline Protection Study15

Goal:

Analyze previously identified flood risk management alternatives (projects) to allow for future planning

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Mandeville’s Entire Historic District in SFHA –Special Flood Hazard Area

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SFHA: Special Flood Hazard Area

FEMA defines the SFHA as the area where the National Flood Insurance Program’s (NFIP) flooodplainmanagement regulations must be enforced and the area where the mandatory purchase of flood insurance applies

Flood Maps - lingo19

Zones AE and VE are:

High Risk Coastal Areas In communities that participate in the NFIP, mandatory flood insurance purchase requirements apply to all of these zones

FEMA defines as follows:

Zone AE: Areas that have a 1% probability of flooding every year (also known as the "100-year floodplain"), and where predicted flood water elevations above mean sea level have been established. Properties in Zone AE are considered to be at high risk of flooding under the National Flood Insurance Program (NFIP).

Zone VE: Coastal areas with a 1% or greater chance of flooding and an additional hazard associated with storm waves. Base flood elevations derived from detailed analyses are shown at selected intervals within these zones.

BFE: The computed elevation to which floodwater is anticipated to rise during the base flood. Base Flood Elevations (BFEs) are shown on FloodInsurance Rate Maps (FIRMs) and on the flood profiles. The BFE is the regulatory requirement for the elevation or floodproofing of structures.

A pretty day on the lakefront20

Overtopping the seawall (5.3’)21

Flood Mitigation/elevation22

Not just flood waters, but all that’s in it….Marsh grass, pigs, snakes

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423 flood claims filed 2005 Katrina/Rita Storm Surge of 9.5’msl - $26,616,924

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226 claims filed after Isaac – Storm surge of 9.5’msl totaling $7,739,531

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The financial value of mitigation

Katrina/Rita - 423 claims @ cost $26,616,924

Isaac - 226 claims @ cost $7,739,531

From Katrina in 2005, to Isaac in 2012, with same storm surge, number of claims was reduced almost in half and damage costs were reduced by 71%.

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According to NOAA – the cumulative damage of 16 U.S. disaster events during 2017 is 306.2 billion, which shatters the previous U.S. annual record cost of $214.8 billion (CPI adjusted), established in 2005 due to the impacts of Hurricanes Dennis, Katrina, Rita and Wilma

Hazard Mitigation Saves! January 11, 2018, the National Institute of Building Sciences found that, on average, every $1 spent on hazard mitigation measures, saves $6 in future disaster costs. For Flood Hazard mitigation $1 spent is $7 saved.

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Reduces Cost of Down time for businesses28

The other storm surge: HFIA Homeowner Flood Insurance Affordability Act

NFIP Increases Began April 2016: 12%/YR FOR PRIMARY RESIDENTIAL – $2500/YR MAX 25% increases for the following:

Non-Primary residences (2nd homes; vacation; rental) Business Buildings (income producing) Severe Repetitive Loss (SRL)

NFIP is reauthorized every 5 years and is up for reauthorization this year. The House version has passed, now Senate has to pass their version, then will vote on final bill. Includes increases in pre-disaster mitigation funding Doubling of Increased Cost of Compliance (ICC) funding.

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PRE-FLOOD MAP BUILDINGS POLICY RATES ARE INCREASING

Many communities have a freeboard requirement, increasing BFE 2’.

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Insurance Premiums: VE zone rated at bottom of lowest horizontal member – in this case, the slab.

VE zone: $12,000 annual policy (to increase annually)

$35,000 annual policy – VE-zone

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Zone AE : significant increases ~ $10,000-$15,000 in four years. Rated at top of finished floor.

Commercial property32

What happens if we don’t mitigate?33

How many do we lose?~

37 structures have been lost or demolished as a result of coastal flooding/storm damage

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Lost – historic structures/fabric35

Mitigation – Relocation36

Entire Historic District in SFHA Special Flood Hazard area

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Regulations and Requirements

Variety of regulations for Flood Hazard Mitigation.

ICC: International Building Codes

NFIP: Regulates on the Insurance side of flood prone properties

FEMA: Regulates Compliance within the SFHA, or flood prone properties

ASCE 24: establishes engineering standards for construction in SFHA. Required on all FMA funded grant projects.

Funding Sources39

PRE-DISASTER Private sources: CASH HOME EQUITY Grant funding: FEMA: FLOOD MITIGATION ASSISTANCE (FMA) HAZARD MITIGATION ASSISTANCE (HMA)Other: FEDERAL HOUSING ADMINISTRATION-FHA 203K

LOAN/MORTGAGE

Funding Sources40

POST DISASTER:Private: CASH INCREASED COST OF COMPLIANCE (ICC) = $30,000 from flood

insurance policyGrants: FEMA HAZARD MITIGATION GRANT PROGRAM (HMGP) HUD-CDBG/DR - HOUSING AND URBAN DEVELOPMENT

COMMUNITY DEVELOPMENT BLOCK GRANT-DISASTER RECOVERY

SMALL BUSINESS ADMINISTRATION-SBA, SBA MAY FUND UP TO $200K ADDITIONAL FOR ELEVATION IF SUBSTANTIALLY DAMAGED

FEMA Bulletin for Historic Structures41

-Explains how the NFIP defines historic structures and how it gives relief to historic structures from NFIP floodplain management requirements.

-Provides guidance on mitigation measures that can be taken to minimize the devastating effects of flooding to historic structures.

-The National Flood Insurance Program (NFIP) gives special consideration to the unique value of one of our Nation’s most significant resources – its historic buildings, landmarks, and sites.

To be eligible for the variance, the structure has to be in a historic district and it has to be “individually listed” within the district.

-If exemptions/variances are utilized, buildings still are at risk for flooding and increasing insurance premiums.

Mandeville’s founder – Bernard de Marigny – original home

Premium ~$35,000 (max) in 4 years – will business community abandon these structures?

Historic Commercial property in VE-Zone42

Reception Hall 43

Below BFE, Base Flood Elevation.

Not only risk of flooding but subject to increasing insurance rates.

Can these businesses survive?

Restaurant in historic building Candy shop

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Historic home – damaged, Again45

Elevation and historic context

If we have to mitigate by elevation, what does it do to the historic context of our communities?

Can we elevate and still maintain context? How can we help the property owner mitigate as

well as preserve our community?

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Zoning Issues

Does your community’s zoning ordinance meet the challenges of elevation? Height? Is 35’ your maximum height? Is there a formula

or exception process for elevation? Setbacks? Front yard – stair encroachment? (6’ above grade) Additional height – more adverse impact on sideyard

setbacks. Elevated structures encroach into privacy (above fence line)

Consider increasing yard setbacks Allow formula for height and allow structure to meet

BFE without variances for height and setbacks.

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Tool box

Master Plan for historic area

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Design Considerations for Elevation of Historic Structures:

Minimize changes to parking and circulation that affect the historic setting. On-street parking Driveways – side loaded with screening of vehicles

Retain and Preserve building features/architectural details that contribute to the historic character of the building and streetscape.

Use screening to mitigate underside of structure/storage and vehicles

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Design considerations for Elevation of Historic Structures

Create systems approach review for structure type Base zone detailing – foundation How does it tie into original structure Pier and column design Screening of vehicles

Previous existing driveway? Parking underneath structure? Does it change context from pedestrian scale to vehicular scale?

Access – stair entries/porches Proportion and scale How does it relate to existing structure? How does it relate to adjacent structures/neighborhood

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Base zone detailing52

Base detailing

Screening in wrong place

Paint lattice a dark color to disappear

Finish CMU block

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Screening corrected

lattice painted dark

CMU blocks finished

Base detailing -

Appropriate screening underneath

Column and piers have correct scale and proportion and line up

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Detailing: Commercial structure

Piers do not line up with columns

Stairs not appropriate

Zoning:

Setbacks

Parking in front

Scale/proportion to street incorrect

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Site vehicular access challenges –front loaded, side or none (on street)?

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Side loaded 57

Front Entry Stair58

Elevations- Stair and Access59

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Elevation - Stair and Access

Stair and Access61

Stair and access62

Stair and access - commercial63

In some areas, tax credits may be used to mitigate historic structures

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Summary

Sea level is projected to rise. Know your risk. Evaluate how many non-compliant structures are located in the SFHA

Insurance rates are rising – NFIP reauthorization this year. Historic Structures are at risk – affects local economy and

character of community. Preservation community embrace mitigation and manage

historic resources, not lose them. Work with local architects to review both

elevation/mitigation projects and new construction Create historic properties in SFHA in the future

Each property is unique – don’t try a broad brush approach Keep the historic context of your community intact

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