Transcript managing coastal wetland impoundments in an era of climate change

COASTAL IMPOUNDMENT DECISION MAKING
ADAPTATION IN ACTION
Rob Hossler and Karen Bennett – Delaware Div. Fish & Wildlife
Austin Kane - National Wildlife Federation
LIONS, TIGERS and On The GROUND CLIMATE
CHANGE ADAPTATION…
OH MY!
Delaware’s Efforts to get over the Fear and Make Decisions to
Implement/Adapt to Climate Change for its Coastal Impoundments
Coastal Impoundments History
Salt hay farming
Rice production
Waterfowl habitat
Mosquito control
Today…Multiple Functions for Wildlife:

Breeding habitat for shorebirds,
rails, bitterns, waterfowl

Roosting habitat for
shorebirds, waterfowl

Feeding habitat for migrating
shorebirds, waterfowl, postbreeding wading birds

Fish nursery habitat

Muskrat habitat
Today…Multiple Socioeconomic Functions:





Waterfowl hunting
Birding, wildlife viewing, photography
Furbearer trapping
Flood-hazard reduction
Mosquito control
Coastal Impoundments in DE:
• State maintains 14 coastal
impoundments comprising
2,400 acres on several state
wildlife areas along the central
to southern Delaware Bay
coast, and a few along the
Atlantic Coast.
• USFWS maintains 1,100 acres
at Bombay Hook NWR and
4,200 acres at Prime Hook
NWR, both along Delaware
Bay coast.
Urgency to Do Adaptation Thrust Upon Us
Breaches 2010
Breaches
2012
Impoundment
Wetland Habitat
at risk
Impoundment wetlands
converting to open water.
Prime Hook NWR – after
Hurricane Sandy 2012.
Prime Hook NWR – after
2009 Mother’s Day storm.
STATE IMPOUNDMENTS ARE NOT IMMUNE!
Breach of State Impoundment Dikes after
Hurricane Irene (2011)
Step 1: Initiation of a State Impoundment
Management Plan/Philosophy
• Collective wisdom of administrator, program and land
managers, and staff scientists to support continued
management and preservation of state impoundments.
• Goal is to Avoided Administrative Neglect, i.e., “I will be
retired before it’s an issue” and make adaptation an
immediate priority among other current funding needs.
• Begin the development of a systematic approach for
evaluating the current status of impoundments,
identifying objectives and developing an adaptive strategy
to enhance resilience in face of climate change.
Multiple OBJECTIVES:
• Maximize Juvenile Fish
Populations
• Maximize Breeding Marsh
• Maintain Furbearer
Birds
populations at a desired level
• Maximize Roosting Red
(e.g., Muskrat)
Knots and Spring
• Minimize Mosquito Production
Migrating Shorebirds
• Maximize Recreational Use
• Maximize Breeding
• Minimize Cost
Shorebirds (e.g., Blacknecked Stilt)
• Maximize Migrating and
Wintering Waterfowl
• Maximize Fall Migrating
Shorebirds
• Maximize Breeding
Waterfowl
Now what??? It’s complicated….
• We can’t manage for everything,
everywhere…not physically possible given
biological needs of target wildlife.
• We’ll never have all the data we think we need.
• Cost constraints and uncertainty are a reality.
• Tradeoffs among competing objectives must
be made.
• We want to find the best combination of
management actions to achieve multiple
affordable objectives in the face of climate
change uncertainty.
Step 2: Approach - Structured Decision Making
• Developed a prototype decision model for 4 impoundments
looking 30 years out (estimated impoundment life span).
• Small team of experts identified key management
objectives and predicted outcomes (e.g., duck-use days,
roosting red knots, mosquito and fish counts) of different
actions under different SLR scenarios (5 and 10 mm/year).
• SDM is an explicit, organized way to deal with multiple,
competing objectives and uncertainty.
• Flexible
• Incorporates cost constraints
• Transparent
• Provides a suite of actions that
maximizes benefit
• Adaptive
GOAL: If we are spending the time and
money on these impoundments we need to
maximize their functions in an explicit,
organized way that deals with multiple,
competing management objectives and cost
constraints under the uncertainty of SLR.
 Coordinated water-level management (% of full pool)
across a suite of impoundments to provide for:
 Vegetation growth (waterfowl)
 Exposed mudflat (shorebirds)
 Pools and channels (fish and mosquitos)
Annual Drawdown Actions
120
% of Full Pool
100
80
MOSQ
REKN
60
WF
Es.Fish
40
DE Saline
20
0
Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov
Influences – Consequences Diagram
Predator
Control
Water
Mgmt
Vegetation
Control
Stopover
Population
Predators
Water Level
Amt. Roost
Habitat
Roosting Red
Knots
Habitat
Configuration
Tide
Weather
Distance to
Foraging
Habitat
Climate
Change
Rectangles = management decision nodes; ovals = stochastic process nodes;
rounded rectangles = intermediate calculations; and hexagons = outcomes
(e.g., objectives).
Utility Functions for Objectives
(b) Red Knot
(c) Fish
1.0
1
0.9
0.9
0.9
0.8
0.8
0.8
0.7
0.7
0.7
0.6
0.6
0.6
0.5
0.4
Value
1.0
Value
Value
(a) Waterfowl
0.5
0.4
0.5
0.4
0.3
0.3
0.3
0.2
0.2
0.2
0.1
0.1
0.1
0.0
0.0
0
10000
20000
Waterfowl Abundance Score
30000
0
0
500
1000
Red Knot Abundance Score
0
1
2
3
4
Fish Score
These objectives were than weighted for Relative Importance.
Example - Red Knots = 0.31 Waterfowl = 0.38 Fish = 0.17
Mosquito = 0.14
5
LONG-TERM ACTIONS UNDER SLR UNCERTAINTY:
 Water management regime?
 Repair levees and water-control structures?
 Raise elevation with thin-layer application of
dredge material?
 Create salt marsh buffers?
 Build new impoundments in uplands?
 Abandon and restore to tidal salt marsh habitat?
Consequences – Predictions and
UncertaintyUncertaint
Uncertainty
y
Impoundment
Action Plan
Sea Level Δ
Base Cost
(k)
Add. Cost
(k)
REKN 10yr REKN 20yr REKN 30yr
Primehook - Unit 3
Action 1 ("WF")
Accelerated Rate
22.5
na
75
50
0
Primehook - Unit 3
Action 1 ("WF")
Current Rate
22.5
na
100
75
50
Primehook - Unit 3
Action 2 ("REKN")
Accelerated Rate
15
na
225
150
0
Primehook - Unit 3
Action 2 ("REKN")
Current Rate
15
na
300
225
150
Primehook - Unit 3
Action 3 ("DE Saline")
Accelerated Rate
10
na
50
0
0
Primehook - Unit 3
Action 3 ("DE Saline")
Current Rate
10
na
50
50
15
Primehook - Unit 3
Act.4: Raise levee, replace WCS +WF
Accelerated Rate
22.5
1200
100
75
50
Primehook - Unit 3
Act.4: Raise levee, replace WCS +WF
Current Rate
22.5
1200
100
100
100
Primehook - Unit 3
Act.5: Raise levee, replace WCS +REKN
Accelerated Rate
15
1200
300
235
150
Primehook - Unit 3
Act.5: Raise levee, replace WCS +REKN
Current Rate
15
1200
300
300
300
Primehook - Unit 3
Act.6: Raise levee, replace WCS +DNREC
Accelerated Rate
10
1200
50
40
25
Primehook - Unit 3
Act.6: Raise levee, replace WCS +DNREC
Current Rate
10
1200
50
50
50
How Do We Decide?
• Each action has an expected benefit.
• Benefit is determined by:
– Species response
– Uncertainty
– Species weighting
• Each action has a cost.
Using Excel “Solver” Add-in:
Mgt. Unit
Unit III PH
Unit III PH
Unit III PH
Unit III PH
Unit III PH
Unit III PH
Raymond
Raymond
Raymond
Raymond
Raymond
LoganS
LoganS
LoganS
LoganS
LoganS
LoganS
LittleCrk
LittleCrk
LittleCrk
LittleCrk
LittleCrk
LittleCrk
Management Action
WEV Waterfowl WEV Knots WEV Fish
A1: Waterfowl water regime
0.3619
0.1234
0.1255
A2: Red Knot water regime
0.2744
0.1623
0.1255
A3 DE Saline water regime
0.1269
0.0269
0.1255
A4: Raise levee, replace wcs, & (A1)
0.6494
0.0748
0.1255
A5: Raise levee, replace wcs, & (A2)
0.2996
0.2251
0.1255
A6: Raise levee, replace wcs, & (A3)
0.2177
0.0376
0.1255
A1: Waterfowl water regime
0.0369
0.0000
0.0000
A2: Red Knot water regime
0.0191
0.0402
0.0000
A3: DE Saline water regime
0.0126
0.0000
0.0000
A4: Raise wcs @ 20 yrs, & (A1)
0.0382
0.0000
0.0000
A5: Raise wcs @ 20 yrs, & (A2)
0.0191
0.0402
0.0000
A1: Waterfowl water regime
0.0217
0.2688
0.0983
A2: Red Knot water regime
0.0209
0.4159
0.0988
A3: DE Saline water regime
0.0152
0.0021
0.2234
A4: Construct new 150 ac imp, pumping, & (A1)
0.0756
0.2812
0.0072
A5: Construct new 150 ac imp, pumping, & (A2)
0.0442
0.3239
0.0072
A6: Construct new 150 ac imp, pumping, & (A3)
0.0415
0.0000
0.0072
A1:Waterfowl water regime
0.0163
0.2776
0.0588
A2: Red Knot water regime
0.0119
0.4226
0.0588
A3: DE Saline water regime
0.0082
0.0000
0.4382
A4: Replace wcs, dike work, sediment control, & (A1)
0.0191
0.3739
0.0308
A5: Replace wcs, dike work, sediment control, & (A2)
0.0137
0.5610
0.0308
A6: Replace wcs, dike work, sediment control, & (A3)
0.0087
0.0000
0.4396
Portfolio
1
0
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
0
1
0
0
0
0
Management Benefit Cost ($K)
0.6108
$23
0.5622
$15
0.2793
$10
0.8497
$1,200
0.6501
$1,200
0.3807
$1,200
0.0369
$2
0.0593
$2
0.0126
$1
0.0382
$200
0.0593
$200
0.3887
$10
0.5355
$10
0.2406
$13
0.3640
$700
0.3752
$700
0.0487
$700
0.3527
$5
0.4933
$5
0.4465
$7
0.4239
$800
0.6055
$800
0.4484
$800
1.6989
$238
1.6989
Waterfowl 0.4138
Red Knot 1.0021
Fish 0.2831
Cost Constraint
$250
Step 3: Pilot Habitat Projects
• Select “no regret” restoration projects anticipated
to have success to restore wetland habitat and
enhance impoundment resiliency to climate
change.
• These project fall in three categories:
 Better Management Practices
 Resiliency in the Form of Structure Integrity (improvements
or buffers).
 Strategic Retreat.
Better Management Practices
• Better Data Collection: Vegetation Transects,
Integrated Waterbird Management and Monitoring
(“IWMM”), Hydrology and Hydraulic studies.
• Are we achieving what we want – qualitatively and
quantitatively?
• Provides baseline for monitoring of pilot projects,
SLR scenarios and evaluating management
practices.
Buffer Construction
Restore old levee
Create tidal marsh
within 106-acre
containment cell,
eventually with tidal
exchange via channel
creation.
Reinforce existing dikes
Strategic Retreat
• Wildlife Conservation Societyfunded project working with
The National Wildlife
Federation.
• Inland retreat of a 389-acre
impoundment where we
have lost some of our
management capabilities to
maximize functions and
values.
• Creates an 86-acre
impoundment complex from
an existing pond and two
agricultural fields augmented
with freshwater to maximizes
functions and values and
replace larger impoundment.
Thank you!!!
• National Fish and Wildlife Foundation
• Wildlife Conservation Society
• State Wildlife Grants and Wildlife and Sport Fish
Restoration
• National Wildlife Federation – Climate Smart Guidance
Project
• Delaware Impoundment Management and SDM Team