Largescale Acquisitions & in Floodplain...

Largescale Acquisitions &

Associated Ecosystem Services

in Floodplain ManagementKAMM

May 2018

Julia Rinaldi, MEMJarred White, EITJohn Bucher, AICP

Agenda

I. Research Objectives

II. Methodology

III. Results

IV.Recommendations

V. Contact Information

Background

Largescale Acquisitions Acquiring multiple structures

on contiguous land with resulting area returned to green

open space with limited allowable use.

Precedents:

Rainbow Bend, WA Hoffman Grove, NJ

Research Objective 1

Gain greater understanding of cost-effectiveness and

viability of individual versus largescale acquisition

projects.

Individual Acquisitions

(“Checkerboarding”)

Largescale Acquisition

Research Objective 2

Gain greater understanding of implications of using

national versus regionally-specific ecosystem service

benefit (ESBs) in a benefit-cost analysis (BCA).

National ESB Values Regional ESB Values

Scenarios

1 2

3 4

• Individual acquisitions

• National ESB values

• Individual acquisitions

• Regional ESB values

• Largescale acquisition

• National ESB values

• Largescale acquisition

• Regional ESB values

Methodology: Project Area Selection

…where to start?

• Results from February 2017 run

of the Mitigation Benefits

Estimator (MBE) Tool

• Used MBE to target viable study

areas (groups of high acquisition

Mitigation Benefit Ratios (MBRs))

• 8 selected hypothetical project

areas (182 structures)

Methodology: Project Area Selection

Methodology: Inputs

For BCA

• Building Replacement Value*

• Depth Damage Function

• First Floor Elevation*

• Parcel Lot Area*

• Flooding Depth*

• Riverine Discharges

• …and many others

Constants

Ecosystem TypeFEMA National Value

(per acre per year)

New Jersey Value

(per acre per year)

Greenspace

(Contiguous)$8,624.92 $3,265.16

Greenspace

(Checkerboard)$993.50 $451.55

Riparian $41,053.50 $4,466.65

Forest $575.13 $1,948.79

Wetlands $6,239.26 $15,273.51

Estuary $1,867.63 $8,093.59

Restoration Action Estimated Cost**

Structure Demolition $5.36 per square foot

Regrading $4.00 per cubic yard

Revegetation

(Contiguous Greenspace)$2,750 per acre

Revegetation

(Checkboard Greenspace)$500 per acre

Revegetation

(All Other)$5,500 per acre

Roadway and Utility Demolition $25,000 per acre

Annual Maintenance Cost

(Contiguous and Checkerboard

Greenspace)

$200 per acre per year

Annual Maintenance Cost

(All Other)$50 per acre per year

* Sourced from MBE* Specific to New Jersey

Methodology: Analysis

For all scenarios of all study areas, the FEMA BCA Toolkit was

used to calculate:

Initial Project BCR

Final Project BCR

(Structure Damages Avoided + Content Damages Avoided)

(Aquisition Cost + Demolition Cost)

(Structure Damages Avoided + Content Damages Avoided + Ecosystem Services Benefits)

(Aquisition Cost + Demolition Cost + Resoration Costs)

Results – Passaic Linwood Study Area

Restoration TypeArea

(Acres)% of Total

Urban Greenspace 1.19 78.9%

Riparian Buffer 0.32 21.1%

Total 1.51 100%

Activity Cost/UnitArea

Cost

Revegetation

(Greenspace)$2,750/acre 1.19 $3,281

Revegetation (Riparian) $5,500/acre 0.32 $1,752

R&U Demolition $25,000/acre 1.51 $37,790

Total - - $42,823

Scenario Initial BCR Final BCR

FEMA Checkerboard 1.100 1.208

NJ Checkerboard 1.100 1.204

FEMA Largescale 0.918 1.023

NJ Largescale 0.918 0.930

Cumulative

BCR from

Toolkit w/o

ESBs or

restoration

Cumulative

BCR inclusive

of ESBs and

restoration

Results – Passaic Linwood Study Area

Restoration TypeArea

(Acres)% of Total

Urban Greenspace 1.19 78.9%

Riparian Buffer 0.32 21.1%

Total 1.51 100%

Activity Cost/UnitArea

Cost

Revegetation

(Greenspace)$2,750/acre 1.19 $3,281

Revegetation (Riparian) $5,500/acre 0.32 $1,752

R&U Demolition $25,000/acre 1.51 $37,790

Total - - $42,823

Scenario Initial BCR Final BCR

FEMA Checkerboard 1.100 1.208

NJ Checkerboard 1.100 1.204

FEMA Largescale 0.918 1.023

NJ Largescale 0.918 0.930

Cumulative

BCR from

Toolkit w/o

ESBs or

restoration

Cumulative

BCR inclusive

of ESBs and

restoration

• BCR increases with addition of

ESBs and restoration benefits.

• Differences b/w FEMA BCR and NJ

BCRs

Results – Checkerboard vs. Largescale

Project Area ESB Values SourceFinal Project BCR(Checkerboard)

Final Project BCR (Largescale)

Atlantic MottsFEMA 4.097 3.202

New Jersey 4.056 3.550

Bergen LamkerFEMA 1.165 0.476


Gloucest PoplarFEMA 7.565 7.340


Gloucester WillowFEMA 5.539 4.958


Passaic LinwoodFEMA 1.208 1.023


Salem CrosslandFEMA 1.391 1.273


Salem PineFEMA 1.943 1.518


Warren RiverFEMA 4.158 3.963


Results – National vs. Regional ESBs

Project Area Project ApproachFinal FEMA Eco

Values BCR

Final NJ Eco

Values BCR

Checkerboard 4.097 4.056

Largescale 3.202 3.550















Salem Crossland

Salem Pine

Warren River

Atlantic Motts

Bergen Lamkar

Gloucest Poplar

Gloucester Willow

Passaic Linwood

Bergen Lamker

Final Project BCR(FEMA ESBs)

Final Project BCR(NJ ESBs)

Conclusions & Recommendations

1. Largescale restoration projects offer higher overall benefits, which can sometimes

translate into viable largescale acquisition projects.

Recommendation: The determination of whether to pursue largescale versus

checkerboard acquisition projects should be done on a case-by-case basis with

detailed assessment.

2. Values assigned to ESBs have meaningful impacts on BCRs and overall benefits.

Recommendation: Locally or regionally appropriate ESBs should be used

whenever possible for most accurate BCA results.

3. Having common ecosystem classification systems would benefit flood mitigation by

providing a “common language” between funding and agencies using BCAs.

Recommendation: A common classification system between agencies to

easier facilitate coordination of mitigation projects.

Contact Information

Julia Rinaldi

[email protected]

John Bucher

[email protected]

Jarred White

[email protected]

Largescale Acquisitions & in Floodplain...

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