Largescale Acquisitions & Associated Ecosystem Services in Floodplain Management. Julia Rinaldi, MEM Jarred White, EIT John Bucher, AICP

Transcription

1 Largescale Acquisitions & Associated Ecosystem Services in Floodplain Management Julia Rinaldi, MEM Jarred White, EIT John Bucher, AICP KAMM May 2018

2 Agenda I. Research Objectives II. Methodology III. Results IV.Recommendations V. Contact Information

3 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

4 Research Objective 1 Gain greater understanding of cost-effectiveness and viability of individual versus largescale acquisition projects. Individual Acquisitions ( Checkerboarding ) Largescale Acquisition

5 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

6 Scenarios 1 2 Individual acquisitions National ESB values Individual acquisitions Regional ESB values 3 4 Largescale acquisition National ESB values Largescale acquisition Regional ESB values

7 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)

8 Methodology: Project Area Selection

9 Methodology: Inputs For BCA Building Replacement Value* Depth Damage Function First Floor Elevation* Parcel Lot Area* Flooding Depth* Constants Ecosystem Type FEMA National Value (per acre per year) New Jersey Value (per acre per year) Greenspace (Contiguous) $8, $3, Greenspace (Checkerboard) $ $ Riparian $41, $4, Forest $ $1, Wetlands $6, $15, Estuary $1, $8, Riverine Discharges and many others * Sourced from MBE Restoration Action Structure Demolition Regrading Revegetation (Contiguous Greenspace) Revegetation (Checkboard Greenspace) Revegetation (All Other) Roadway and Utility Demolition Annual Maintenance Cost (Contiguous and Checkerboard Greenspace) Annual Maintenance Cost (All Other) Estimated Cost** $5.36 per square foot $4.00 per cubic yard $2,750 per acre $500 per acre $5,500 per acre $25,000 per acre $200 per acre per year $50 per acre per year * Specific to New Jersey

10 Methodology: Analysis For all scenarios of all study areas, the FEMA BCA Toolkit was used to calculate: Initial Project BCR (Structure Damages Avoided + Content Damages Avoided) (Aquisition Cost + Demolition Cost) Final Project BCR (Structure Damages Avoided + Content Damages Avoided + Ecosystem Services Benefits) (Aquisition Cost + Demolition Cost + Resoration Costs)

11 Results Passaic Linwood Study Area Restoration Type Area (Acres) % of Total Urban Greenspace % Riparian Buffer % Total % Activity Cost/Unit Area 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 NJ Checkerboard FEMA Largescale NJ Largescale Cumulative BCR from Toolkit w/o ESBs or restoration Cumulative BCR inclusive of ESBs and restoration

12 Results Passaic Linwood Study Area Restoration Type Area (Acres) % of Total Urban Greenspace % Riparian Buffer % Total % Activity Cost/Unit Area 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 NJ Checkerboard FEMA Largescale NJ Largescale Cumulative BCR from Toolkit w/o ESBs or restoration Cumulative BCR inclusive of ESBs and restoration

13 Results Passaic Linwood Study Area Restoration Type Area (Acres) % of Total Urban Greenspace % Riparian Buffer % Total % Activity Cost/Unit Area 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 NJ Checkerboard FEMA Largescale BCR increases with addition of ESBs and restoration benefits. NJ Largescale Differences b/w FEMA BCR and NJ BCRs Cumulative BCR from Toolkit w/o ESBs or restoration Cumulative BCR inclusive of ESBs and restoration

14 Results Checkerboard vs. Largescale Project Area ESB Values Source Final Project BCR (Checkerboard) Final Project BCR (Largescale) Atlantic Motts Bergen Lamker Gloucest Poplar Gloucester Willow Passaic Linwood Salem Crossland Salem Pine Warren River FEMA New Jersey FEMA New Jersey FEMA New Jersey FEMA New Jersey FEMA New Jersey FEMA New Jersey FEMA New Jersey FEMA New Jersey

15 Results National vs. Regional ESBs Project Area Project Approach Final Project FEMA Eco BCR Values (FEMA ESBs) BCR Final NJ Eco Values (NJ ESBs) BCR Final Project BCR Atlantic Motts Bergen Lamkar Lamker Gloucest Poplar Gloucester Willow Passaic Linwood Salem Crossland Salem Pine Warren River Checkerboard Largescale Checkerboard Largescale Checkerboard Largescale Checkerboard Largescale Checkerboard Largescale Checkerboard Largescale Checkerboard Largescale Checkerboard Largescale

16 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.

17 Contact Information Julia Rinaldi John Bucher Jarred White