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Cost / Benefit Analysis for the Restoration of Riverine Systems Impacted by Legacy Sediment Presented to 2012 Choose Clean Water Conference Lancaster, PA By Conor Gillespie, CPESC, MBA [email protected] May 2012

Land Conservation Strategies- Conor Gillespie

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Presentation given by Conor Gillespie on June 4, 2012 at the Third Annual Choose Clean Water Conference.

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Page 1: Land Conservation Strategies- Conor Gillespie

Cost / Benefit Analysis for the

Restoration of Riverine Systems Impacted by

Legacy Sediment

Presented to

2012 Choose Clean Water ConferenceLancaster, PA

By

Conor Gillespie, CPESC, MBA

[email protected]

May 2012

Page 2: Land Conservation Strategies- Conor Gillespie

Legacy SedimentHydric Soils

Basal Gravels

Existing Conditions

Legacy Sediment is the impairment to the aquatic resource

Page 3: Land Conservation Strategies- Conor Gillespie

Hard Armor Approach

Cost $200 - $250 / lf

Long Term Risk- Failure of armoring resulting in renewed erosion of impairment

Existing Grade

Short Term Benefit- Reduced erosion of impairment

- Minimal improvement to aquatic resource

Legacy Sediment

Hydric SoilsBasal Gravels

Artificially Elevated StreambedImbricated Wall

Page 4: Land Conservation Strategies- Conor Gillespie

Soft Armor Approach

Cost $100 - $150 / lf

Existing Grade

Short Term Benefit- Reduced erosion of impairment

- Moderate improvement to aquatic resource

Legacy Sediment

Hydric SoilsBasal Gravels

Bioengineering

Long Term Risk- Failure of bioengineering resulting in renewed erosion of impairment

Page 5: Land Conservation Strategies- Conor Gillespie

Floodplain Restoration

Cost $100 - $200 / lf

Existing Grade

Hydric SoilsBasal Gravels

Short & Long Term Benefit- Removal of impairment

- Restored function of aquatic resource

Page 6: Land Conservation Strategies- Conor Gillespie

Natural Piedmont Stream Valley

Floodplain Soils –Shallow, Peaty,Organic, & Porous

BedrockCobble/Gravel Bed (Groundwater)

Connectivity betweenRooting Zone,Groundwater,andStream Flow

Roots extendto groundwater

Page 7: Land Conservation Strategies- Conor Gillespie

Hydrologic Functions: Maximizing Hydrologic Functions: Maximizing Sediment, Nutrient, and Carbon Sediment, Nutrient, and Carbon

Retention in Natural SystemsRetention in Natural Systems

Beaver Dam Controlled Stream Marshland

Page 8: Land Conservation Strategies- Conor Gillespie

Sediment and Nutrient Reduction

Groundwater Recharge

Stormwater Management

Wetland Creation

Regional Flood Reduction

Carbon Retention

Wildlife Habitat Improvement

Invasive Species Removal

Fisheries Improvements

Thermal Improvements – Base Flow

Potential Objectives of Riverine System Restoration

Page 9: Land Conservation Strategies- Conor Gillespie

Restore the natural floodplain, stream and riparian wetland Restore the natural floodplain, stream and riparian wetland functions to its natural ecological potential.functions to its natural ecological potential.

Maximize removal of nutrients and sedimentsMaximize removal of nutrients and sediments

Big Spring Run Restoration

Small headwater stream/springs – characteristic of a sedge dominated wet meadow – Bog Turtle Habitat.

Areas seasonally flooded and extremely wet.

Frequent exchange and interaction between channels and floodplain.

Over time, vegetation will encroach upon the channel increasing carbon, nutrient and sediment retention. The objectives will

improve over time and not be considered optimum immediately after restoration similar to the previous projects discussed.

Page 10: Land Conservation Strategies- Conor Gillespie

Full-Depth Floodplain Restoration Design Features

Channel directly linked to groundwater/bedrock.

Floodplain Elevation – Preferably 6 to 12 inches with vernal pools to maximize – retention areas. This allows the root zone to quickly access and stabilize the floodplain.

Planform is sinuous, single, multi-thread channel or no defined channel; similar to headwater marshes or wet meadows.

Maximize width of floodplain and condition soils for vegetation/root penetration.

Woody debris throughout channel(s) & floodplain.

Page 11: Land Conservation Strategies- Conor Gillespie

Big Spring Run

Pre-settlement floodplain

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Benefit Value Hard Armor$225

Soft Armor$125

Floodplain Restoration

$170

Total Cost $688,500 $382,500 $522,500

Stream Mitigation Dollar Values Vary by State

Mitigation Possibly Achieved

Mitigation Achieved

Mitigation Achieved

Wetland Mitigation$ / ac*

$77,500 / ac($60,000 - $85,000)

$0 $0 $310,000(4 ac)

Wildlife Habitat Conservation Banking Credits

Minimal Medium Maximum

Sediment / Nutrient Reduction (On-site)**

N – $3.37P – $4.73

??? / yrShort term

??? / yrShort term

??? / yrLong Term

Sediment / Nutrient from upstream sources

N – $3.37P – $4.73

$0 / yrTransport

$0 / yrTransport

??? / yrRetention

Legacy Sediment Re-use***

$14$3 - $25 / cy

$2,380(170 cy)

$4,760(340 cy)

$280,000(20,000 cy)

Floodwater Storage None Minimal 12 ac/ft

Infrastructure Maint. Requirements

Likely Likely Minimal

Cost Benefit AnalysisBig Spring Run Case Study

3,060 lf of Restoration

*Courtesy of Resource Environmental Solutions, LLC; Estimated Wetland Mitigation Credit Prices for the State of PA based off current market conditions** Prices based of results of PennVEST Spot and Forward Nutrient Auctions; October 28, 2010 - March 21, 2012*** Courtesy of Joe Sweeney, based on estimated re-sale value of Legacy Sediment from Big Spring Run project

Page 17: Land Conservation Strategies- Conor Gillespie

Cost Benefit Analysis

Benefit Value Hard Armor$225

Soft Armor$125

Floodplain Restoration

$170

Total Cost $688,500 $382,500 $522,500

Total Monetary Benefit $2,380 $4,760 $590,000

Simple Return on Investment

- 99.65% - 98.75% 12.9%

Big Spring Run Case Study3,060 lf of Restoration

Additional Site Specific Benefits with Monetary Value

- Sustainable, Low Impact Site Development- On-site water retention and usage- Reduction in stormwater fee’s due to increased infiltration

Future Market Drivers

- MS4 Permit Requirements- Chesapeake Bay TMDL’s- Wetland Creation & Mitigation

Page 18: Land Conservation Strategies- Conor Gillespie

Thank You