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Enhancing SmartConservation ™ : Green Infrastructure Plan Development Robert Cheetham Avencia Incorporated Clare Billett Natural Lands Trust Funding provided by William Penn Foundation. Overall Objectives.
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Enhancing SmartConservation™ : Green Infrastructure Plan Development Robert Cheetham Avencia Incorporated Clare Billett Natural Lands Trust Funding provided by William Penn Foundation
Overall Objectives Develop a green infrastructure plan for SE PA made up of hubs and corridors. Develop a methodology to use in the site-to-site assessment to score SmartConservation™sites based on their proximity to these hubs and corridors – but we’ll defer this until the hubs and corridors are established.
Hubs • Existing Protected Lands (gov & NGO - not ag. lands) • Lands with top 20% of region-wide SmartConservation mapped natural resources • All CNAI-PNDI Locations
Merged Hubs Merged Hubs Protected Lands Before merge merge PNDI Cons. Resource Locations After merge
Corridors - The Real Question • How can we connect the hubs? • Where should the corridors be? • How far is any corridor location from a hub?
Distance vs. ‘Cost Distance’ • Distance ‘as-the-crow-flies’ is really not the distance that we want. • We want to account for ‘barriers’ in the landscape as well as factors that overcome barriers. • We also want to account for ‘density’ of nearby protected lands. • We can use the concept of ‘travel cost’ to model this.
Linear Distance • Like spinning a ruler around a center
What is Cost Distance ? Concept:It costs more to travel through certain ‘cells’ Input:Hubs Friction/Permeability/Cost Surface Output:Represents Accumulated Least Cost from source location (hub) to destination location (another hub)
What is Cost Distance? Cost: Barriers to travel (including factors that might ‘reduce’ barriers) Higher cost values means greater barrier Examples: Roads Wind Railways Salinity Gradient Water
How is it used? – an Example Cost Distance to Sample Site from other protected lands
How is it used? – an Example Least Cost Path from Sample Site to Protected Lands
Green Infrastructure Development Method - TASKS 1. General Permeability Layer Development 2. Corridor Identification Methodology 3. Aquatic Corridor Development
Task 1 Objectives Develop a map layer that represents the degree of permeability for terrestrial movement of animals which migrate through the landscape …but also encapsulates the size, shape and degree of protection for each hub
Barriers • Roads Class • Active Railways • Higher Order Streams • Water bodies Barriers are 50% of Travel Cost
Density • Roads • Active Railways • Higher Order Streams Density is 50% of Travel Cost
Density – 500m • Density calculation done with a radius of 500 m.
Density – 1000m • Density calculation done with a radius of 1000 m.
Density – 1000m w/ CLASS NLT selected this one to use • Density calculation done with a radius of 1000 m and using CLASS as calculation factor.
Density – 2000m • Density calculation done with a radius of 2000 m.
Building the Corridors Basic Principles: • Corridors connect Hubs • Corridors occupy the Least Cost Path between two hubs • Corridor networks are calculated at different scales (regional/ subregional /local) • When multiple corridors are available, the one that combines the best average conservation value, plus destination hub value, will prevail.
Hub Proximity Values • Merged protected land sites with overlapping donut buffers of 1km and 2 km and values of 50% and 10 % respectively. Overlap region with cumulative proximity values
Modified Impermeability - ( + ) Modified Impedance = Barriers Conservation Value Hub Proximity
Modifying Impermeability Again 300 ft 2000 ft 60 ft Least Cost Path w/ modification Least Cost Path w/o modification • Adjust Cost Layer by using Maximum Cost in 150m radius around each cell • Create ‘Snowplow’ effect to encourage paths through areas with best average conservation value and least average barrier costs -- across the entire corridor width of 300m(or 1100ft)
Neighborhood Maximum 5 8 6 3 5 0 1 5 1 8 In Out
Neighborhood Maximum 1 4 3 1 1 3 3 2 1 3 1 1 1 1 1 1 1 2 1 1 0 1 1 2 0 3 4 4 3 4 3 4 4 3 4 3 2 3 2 3 1 2 2 2 2 1 2 2 3 1
Modifying Impermeability Again 300 ft 2000 ft 60 ft Least Cost Path w/ modification Least Cost Path w/o modification • Adjust Cost Layer by using Maximum Cost in 150m radius around each cell • Create ‘Snowplow’ effect to encourage paths through areas with best average conservation value and least average barrier costs -- across the entire corridor width of 300m(or 1100ft)
Modified Impedance • Conservation Resource Value, Protected Land ‘Zone of Influence’ values have been subtracted.
Building the Green Infrastructure Network Basic Principles: • Adjacent and overlapping hubs should be treated as a single hub • ‘Travel Cost’ between hubs is a function of both the barrier types and the density of the barriers. • Barriers have different relative impact values depending on their impermeability (e.g. relative amount of traffic or similar measure such as width, etc.) • Density and Barrier type impact value each comprise 50% of the total corridor cost. • Density is calculated at using a 1000m search radius • Corridor Cost is reduced by 2 factors: • Conservation Resource Value • Proximity to Hubs • Corridor Cost is based on the average cost and values for the entire 300m corridor width, (not just one cell width and then buffered as with other least cost path green infrastructure processes (e.g. TCF, MNRD, etc)).
Discussion Points - This Afternoon P1: Road Class Barrier Cost (value) P2: Railway Barrier Cost (value) P3: Ordered Stream Barrier Cost (value) P4: Water Body Barrier Cost (value)
Green Infrastructure Development Method - Next Steps • 1. General Permeability Layer Development • 2. Corridor Identification Methodology • 3. Aquatic Corridor Development
Task 2 Objective Establish corridors between connecting hubs based on hub size classes
Connect Large Hubs Create a Network of Corridors using the following parameters: • For each Hub > 1000 acres, select all other hubs within 30 miles • Draw ‘least cost path’ to each • Create a Cost Corridor • A = Corridor Conservation Value • B = Hub Conservation Value • C = Length, Cost Length • Corridor Value = Average (A + B) • Select Top 3 • Repeat
Connect Medium Hubs Create a Network of Corridors using the following parameters: • For each Hub > 500 acres, select all other hubs within 15 miles • Draw ‘least cost path’ to each • Create a Cost Corridor • A = Corridor Conservation Value. • B = Hub Conservation Value • Corridor Value = Average(A + B) • Select Top 5 • Repeat
Connect Small Hubs Create a Network of Corridors using the following parameters: • For each Hub > 100 acres, select all other hubs within 3 miles • Draw ‘least cost path’ to each • Create a Cost Corridor • A = Corridor Conservation Value. • B = Hub Conservation Value • Corridor Value = Average (A + B) • Select Top 5 • Repeat
Least Cost Path - Example Least cost path -- between source & destination hubs