Enhancing SmartConservation™ :Green Infrastructure Plan

Development

Robert CheethamAvencia Incorporated

Clare BillettNatural 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

1. Existing Protected Lands(gov & NGO - not ag. lands)

1. Lands with top 20% of region-wide SmartConservation mapped natural resources

2. All CNAI-PNDI Locations

Protected Lands

Conservation Resource Lands

PNDI Lands

Merged Hubs

Protected Lands

PNDI

Cons. Resource Locations

Merged Hubs

merge

Before merge

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: HubsFriction/Permeability/Cost Surface

Output: Represents Accumulated Least Costfrom 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

What is Cost Distance?

Cost Distance to Sample Site from other protected lands

How is it used? – an Example

Least Cost Path from Sample Site to Protected Lands

How is it used? – an Example

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

1. Roads Class2. Active Railways3. Higher Order Streams4. Water bodies

Barriers are 50% of Travel Cost

Streets

Active Railways

Ordered Streams

Water bodies

Relative Travel CostRelative Travel Cost

0

20

40

60

80

100

120

Barrier

Co

st

Combine Barriers

Density

1. Roads2. Active Railways3. 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.

Preliminary Impedance

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 cumulativeproximity values

Conservation Resource Value

Modified Impermeability

+Modified Impedance -= ( )Barriers Conservati

on ValueHub Proximity

Modifying Impermeability Again• 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)

Least Cost Path w/o modification

2000 ft

300 ft

60 ft

Least Cost Path w/ modification

Neighborhood Maximum

5 86

3 50

1 51

8

In Out

Neighborhood Maximum

1 4 3 11

3 3 2 13

1 2 1 11

1 1 2 11

0 1 1 10

3 4 4 34

3 4 4 34

3 3 3 23

1 2 2 22

1 2 2 21

Modifying Impermeability Again• 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)

Least Cost Path w/o modification

2000 ft

300 ft

60 ft

Least Cost Path w/ modification

Preliminary Impedance

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

Hubs

Conceptual Corridor Network

Create a Network of Corridors using the following parameters:

1. For each Hub > 1000 acres, select all other hubs within 30 miles

2. Draw ‘least cost path’ to each3. Create a Cost Corridor4. A = Corridor Conservation Value5. B = Hub Conservation Value6. C = Length, Cost Length7. Corridor Value = Average (A + B)8. Select Top 39. Repeat

Connect Large Hubs

Create a Network of Corridors using the following parameters:

1. For each Hub > 500 acres, select all other hubs within 15 miles

2. Draw ‘least cost path’ to each3. Create a Cost Corridor4. A = Corridor Conservation Value. 5. B = Hub Conservation Value6. Corridor Value = Average(A + B)7. Select Top 58. Repeat

Connect Medium Hubs

Create a Network of Corridors using the following parameters:

1. For each Hub > 100 acres, select all other hubs within 3 miles

2. Draw ‘least cost path’ to each3. Create a Cost Corridor4. A = Corridor Conservation Value. 5. B = Hub Conservation Value6. Corridor Value = Average (A + B)7. Select Top 58. Repeat

Connect Small Hubs

Least Cost Path - ExampleLeast cost path -- between source & destination hubs

Least Cost Path - ExampleLeast cost path -- between source & destination hubs

Cost Weighted Corridor - Example

• Corridor calculation using the cost weighted method with minimum extent radius of 10 cost units

Cost Corridor between source & destination hubs

Cost Weighted Corridor - Example

• Corridor calculation using the cost weighted method with minimum extent radius of 10 cost units

Cost Corridor between source & destination hubs

Discussion Points - This Afternoon

CI 1: Network scales

Network Scale

Hub Size Search Radius # of Corridors per hub

Large >1000 acres

30 miles 3

Medium >500 acres

10 miles 3

Small >250 acres

5 miles 3

Green Infrastructure Development Method - Next Steps

1. General Permeability Layer Development

2. Corridor Identification Methodology

3. Aquatic Corridor Development

Task 3 Objectives

Create

special aquatic corridors

that connect hubs using riparian corridors

Aquatic Corridors are built from…

1. Ordered Streams2. Water bodies3. Floodplains4. Wetlands5. Hydric Soils

Stream Order 1-2

Stream Order 3-5

Stream Order 6-12

Flood Plains

Wetlands

Hydric Soils

Water Bodies

Sample Corridor

Sample Corridor

Choosing Aquatic Corridors

The best Aquatic Corridors have:

• Fewest Barriers

• Highest Aquatic Value

Aquatic Barriers are ...

1. Dams (>5ft): 5 points

2. Bridges/CulvertsStream Order 1-2: 3 pointsStream Order 3-5: 2 pointsStream Order 6+: 1 points

Bridges/Culverts 1-2• Bridges 1-2 were

defined by extracting intersection points of roads and streams of order 1-2

Bridges/Culverts 3-5• Bridges 3-5 were

defined by extracting intersection points of roads and streams of order 3-5

Bridges/Culverts 6-12• Bridges 6-12

were defined by extracting intersection points of roads and streams of order 6-12

Dams

Aquatic Conservation Value

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 cumulativeproximity values

Basic Principles:

Aquatic Corridors are Special and the best ones should be highlighted

The Travel Cost approach is not appropriate for aquatic corridors due to the limited number of possible routes

Aquatic corridors are made up from combinations of:- Ordered Streams- Water bodies- Floodplains- Wetlands- Hydric Soils

Aquatic corridor “barriers” are Dams and Bridges/Culverts

The best aquatic corridors are:- Less impeded by dams and other barriers- Have higher aquatic conservation value- Lead to hubs of high conservation value

Highlighting Special Aquatic Corridors

Discussion Points - This Afternoon

AQ1: Aquatic Corridor Value Formula

Input Layers Value Factor Maximum

Conservation Value Layers

Aquatic Conservation Value 0 - 10 2 20

Hub Proximity 0 – 10 2 20

 

Barrier Layers

Dams 5 # of dams

20

Bridges/Culverts 1-3 # of bridges/culverts