Land Conservation Strategies- Conor Gillespie
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Transcript of 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
May 2012
Legacy SedimentHydric Soils
Basal Gravels
Existing Conditions
Legacy Sediment is the impairment to the aquatic resource
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
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
Floodplain Restoration
Cost $100 - $200 / lf
Existing Grade
Hydric SoilsBasal Gravels
Short & Long Term Benefit- Removal of impairment
- Restored function of aquatic resource
Natural Piedmont Stream Valley
Floodplain Soils –Shallow, Peaty,Organic, & Porous
BedrockCobble/Gravel Bed (Groundwater)
Connectivity betweenRooting Zone,Groundwater,andStream Flow
Roots extendto groundwater
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
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
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.
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.
Big Spring Run
Pre-settlement floodplain
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
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
Thank You