Transcript CHOOSING A PATH FORWARD FOR THE CHESAPEAKE BAY AND ITS WATERSHED Seminar For International Visitors June 26, 2012 Lewis Linker and CBP Modeling Team U.S.

CHOOSING A
PATH
FORWARD
FOR THE
CHESAPEAKE
BAY AND ITS
WATERSHED
Seminar For International Visitors
June 26, 2012
Lewis Linker and CBP Modeling Team
U.S. EPA Chesapeake Bay Program Office
Jane Thomas/IAN
We need to
view the CBP
integrated
models of the
airshed,
watershed, and
tidal Bay
models as a
whole.
Together they
relate the
watershed and
airshed loads to
water quality
impairments in
the Chesapeake.
2
Chesapeake Bay WatershedBy the Numbers
• Largest U.S. estuary
• Six-states and DC, 64,000
square mile watershed
• 10,000 miles of shoreline
(longer then entire U.S. west
coast)
• Over 3,600 species of plants,
fish and other animals
• Average depth: 21 feet
• Home to 17 million people
(and counting) and 77,000
(principally) family farms
• Declared “national treasure” by
President Obama
….but, low to no
dissolved oxygen
in the Bay every
summer
3
Source: www.chesapeakebay.net
What happens on the land affects all
estuaries, but especially the Chesapeake
R ela tive W a tersh ed S izes
(m e tric u n its )
Largest
land to
water
ratio of all
estuaries.
C h es a pe a k e B a y
G u lf of Fin la nd
Ara bian (P ersia n ) G ulf
B a ltic S e a
G re a t La ke s
S e a o f C o rte z
N o rth S e a
B lac k S e a
Red Sea
M e diterra n e an S e a
G u lf of M e x ico
S o uth C h ina S ea
S e a o f Ja pa n
0
10 00
20 00
W a te rs h ed /V o lu m e R a tio
30 00
Summary: 2008 Bay Health Assessment
Restored Bay
Priority Areas
Water Quality
Dissolved Oxygen
21%
of
Goals Achieved
16
Mid-Channel Clarity
14
Chlorophyll a
27
Chemical Contaminants
28
Habitats & Lower Food Web
Bay Grasses
42
Phytoplankton
45%
of
Goals Achieved
Fish & Shellfish
48%
of
Goals Achieved
53
Bottom Habitat
Tidal Wetlands
42
Not quantified in relation to a goal
Blue Crab
Oyster
60
9
Striped Bass
100
Shad
Juvenile Menhaden
23
Not quantified in relation to a goal
6
Data and Methods: www.chesapeakebay.net/status_bayhealth.aspx
The Chesapeake Bay TMDL
• EPA sets basin-State nutrient
and sediment targets to meet
states’ Bay clean water
standards.
• Caps on nitrogen, phosphorus
and sediment loads for all 6
Bay watershed States and DC
• With the State-basin targets
the States set load caps for
point and non-point sources
7
Taking Responsibility for Load
Reductions
Identify
basinwide
target loads
EPA, States,
Identify major
basin by
jurisdiction
target loads
8
Identify tidal segment
watershed, county and
source sector target loads
States, DC, local
Bay Dissolved Oxygen Minimum Amount of Oxygen
(mg/L) Needed to Survive by
Criteria
Species
Migratory Fish Spawning &
Nursery Areas
6
Striped Bass: 5-6
Shallow and Open Water
Areas
5
American Shad: 5
White Perch: 5
4
Hard Clams: 5
Deep Water
Deep Channel
Yellow Perch: 5
3
Alewife: 3.6
2
Crabs: 3 Bay Anchovy: 3
1
0
Spot: 2
Worms: 1
Refined Designated Uses for
the Bay and Tidal Tributary Waters
A. Cross Section of Chesapeake Bay or Tidal Tributary
Shallow-Water
Bay Grass Use
Open-Water
Fish and Shellfish Use
Deep-Water
Seasonal Fish and
Shellfish Use
Deep-Channel
Seasonal Refuge Use
B. Oblique View of the “Chesapeake Bay” and its Tidal Tributaries
Migratory Fish
Spawning and
Nursery Use
Shallow-Water
Bay Grass Use
Deep-Water
Seasonal Fish and
Shellfish Use
Open-Water
Habitat
Deep-Channel Seasonal Refuge Use
Source: U.S. EPA 2003
11
Healthy vs. Unhealthy Bay Water Quality
Sunlight
Minimal Nitrogen,
Phosphorus and
Sediment Inputs
Excessive Nitrogen,
Phosphorus and
Sediment Inputs
Sunlight
Algal Bloom
Healthy
Bay Grasses
Balanced
Algae Growth
Reduced
Bay Grasses
Healthy Unhealt
Habitat hy
Habitat
Algae Die-off
Algae
Decomposition
Healthy
Oyster
Reef
Benthic Community
Adequate
Oxygen
No Oxygen
Barren
Oyster
Reef
No Benthic Community
Source: www.chesapeakebay.net
Nitrogen Loads to the Chesapeake
Time series of atmospheric, fertilizer, manure, and
point source nitrogen input loads to the Chesapeake
Bay Water Quality and Sediment TransportPoint
Model.
sources
1000
Total Nitrogen Input Loads (millions of lbs/yr)
Atmospheric Deposition
900
N Fertilizer
N Manure
800
700
600
500
400
300
200
100
0
1980
1985
1990
1995
2000
2005
2010
An Overview of the CBP Integrated Models:
Basic Chesapeake Bay Modeling Structure - 2003
A Regression Model of 15 monitoring sites
over 10 simulation years.
Changes in air quality management
simulated with the
Regional Acid Deposition Model (RADM)
with a domain covering the Eastern states
and limited grid capabilities
Watershed Model Phase 4.3
94 model segments, 9 land uses, 20
calibration sites, 10 simulation years,
fixed annual land use
Chesapeake Bay
Water Quality Model
Hydrodynamic Model, Sediment
Benthic Model, and Submerged
Aquatic Vegetation, 10 simulation
years, 13,000 model cells
16
An Overview of the CBP Integrated Models:
Basic Chesapeake Bay Modeling Structure – 2009 to present
Nitrate and ammonia deposition from
improved Daily Nitrate and Ammonium
Concentration Models using 35 monitoring
stations over 18 simulation years.
Adjustments to deposition from the
Community Multi-scale Air Quality (CMAQ)
Modeling System
Phase 5 Watershed Model
Year-to-year changes in land use and
BMPs; 899 segments; 24 land uses; 296
calibration stations; 21 simulation years;
sophisticated calibration procedures;
calibration demonstrably better in
quality and scale
Chesapeake Bay Estuary Model
Detailed sediment input; Wave
model for resuspension, Full
sediment transport; Filter feeder
simulation; Simulation of Potomac
17cells;
algal blooms; 54,000 model
18 simulation years
Environmental Management Information Needs:
• How are pollutant sources ranked? What are cost effective
reductions?
• What are my loads and how do they compare to other sources in
the watershed?
• What is the range of feasible reductions?
• What is the range of meaningful/environmentally protective
reductions?
• What are equitable reductions?
• What are cost effective reductions?
• What are the expected water quality and living resource
improvements?
• What are the load reductions necessary to meet water quality
standards in all 92 Bay segments?
• Understanding affects of alternative policies, regulations, and
authorities.
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History of CBP Airshed Model
The 1st generation CBP Airshed Model
(RADM) covered only the Eastern US.
The current 2nd generation CBP
Airshed Model, CMAQ, is a
continental scale “one-model” design
and uses a nested grid of 36 km in the
US and a 12 km fine grid for the
Chesapeake watershed.
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The Bay Airshed Model - CMAQ
Combining
a regression
model of
wetfall
deposition...
…with
CMAQ
estimates
of dry
deposition
for the
base…
…and using the
power of the
CMAQ model20for
scenarios.
A Quarter Century of Watershed Model Development
Phase 1
• Completed in 1982.
• 63 model segments.
• 2 year calibration period
(Mar.- Oct.).
• 5 land uses.
Phase 4
• Completed in 1998.
• 94 model segments.
• 9 land uses.
• 14 year calibration period (198497) using automated input and
output model processors.
Phase 5
• May 2009 roll-out
• ~ 1,000 model segments.
• 21 year calibration period (‘85’05).
• ~ 25 land uses using time-varying
land use & BMPs.
21
Finer Segmentation and Longer Simulation Periods
Increases the Calibration Sites By An Order of Magnitude
Phase 4 Segmentation and
Calibration Sites
Calibration sites = 20
Land Segments = 94
River Segments = 94
Land uses = 9
Simulation Years = 10
Phase 5 Segmentation and
Calibration Sites
Calibration sites = 296
Land Segments = 308
River Segments= 1,063
Land uses = 25
Simulation Years = 20
22 22
How the Watershed Model Works
Annual or Monthly:
Land Use Acreage
BMPs
Fertilizer
Manure
Atmospheric Deposition
Point Sources
Septic Loads
Hourly Values:
Rainfall
Snowfall
Temperature
Evapotranspiration
Wind
Solar Radiation
Dewpoint
Cloud Cover
HSPF
Daily output compared
To observations23 23
How the Watershed Model Works
Each segment consists of separately-modeled land uses:
•
•
•
•
•
•
•
•
High Density Pervious Urban
High Density Impervious Urban
Low Density Pervious Urban
Low Density Impervious Urban
Construction
Extractive
Forest/Woodland
Disturbed Forest
Plus: Point Source and
Septic Loads, and
Atmospheric
Deposition Loads
• Corn/Soy/Wheat rotation (high
till)
• Corn/Soy/Wheat rotation (low
till)
• Other Crops
• Alfalfa
• Nursery
• Pasture
• Degraded Riparian Pasture
• Animal Feeding Operations
• Fertilized Hay
• Unfertilized Hay
– Nutrient management versions
of the above
Each calibrated to nutrient and
Sediment targets
24 24
How the Watershed Model Works
Each land use type is divided into four soil layers:
Water, Sediment, Nitrogen, Phosphorus
25 25
How the Watershed Model Works
Denitrification
Trees
Roots
Leaves
Atmospheric Deposition
Nitrate
Export
Solution
Ammonia
Export
Export
Adsorbed
Ammonia
Particulate
Labile
Organic N
Export
Export
Solution
Labile
Organic N
Each
submodel
has a
complex
hydrologic
or nutrient
cycling
structure.
Particulate
Refractory
Organic N
Export
Export
Solution
Refractory
Organic N
26 26
ble 6.4.3b. Jurisdictional BMP Listing for the Chesapeake Bay Program.
A Short List of
the Management
Practices
Simulated by the
Watershed Model
Agricultural BMPs
Conservation Tillage
Forest Buffers (Agriculture)
Wetland Restoration
Agricultural Land Retirement
Grass Buffers (Agriculture)
Tree Planting (Agriculture)
Nutrient Management Plan Implementation
(Agriculture)
Farm Plans/Soil Conservation Water Quality Plans
(Non-Nutrient Management Plans)
Cover Crops
Stream Protection with Fencing / Stream
Stabilization-Restoration
Stream Protection without Fencing
Rotational Grazing/Grazing Land Protection
Animal Waste Management Systems:
Animal Waste Management Systems:
Livestock
Animal Waste Management Systems: Poultry
Units
acres
acres
acres
acres
acres
acres
acres
Land Use Applied To
High-Till to Low-Till
High-Till, Low-Till, Hay
High-Till, Low-Till, Hay
High-Till, Low-Till, Hay
High-Till, Low-Till
High-Till, Low-Till, Pasture
High-Till, Low-Till, Hay
acres
High-Till, Low-Till, Hay,
Pasture
High-Till, Low-Till
Pasture
acres
acres or
linear
feet
acres
acres
systems
systems
Barnyard Runoff Control
systems
Loafing Lot Management
systems
Developed Land and Other BMPs
Forest Conservation
Abandoned Mine Reclamation
Units
acres
acres
Stormwater Management:
Stormwater Dry and Extended Detention
Ponds
Stormwater Wet Ponds
acres
Stormwater Wetlands
acres
Infiltration Practices
acres
Filtering Practices
acres
Open Channel Practices
acres
Non-Structural Practices
acres
Hydrodynamic or Other Structural Practices
(Pretreatment or Retrofit Only)
acres
acres
Pasture
Pasture
1 (One) system treats waste
from 145 animal units
1 (One) system treats waste
from 145 animal units
1 (One) system treats waste
from 145 animal units
1 (One) system treats waste
from 145 animal units
Land Use Applied To
Pervious Urban
Pervious and Impervious
Urban
Pervious and Impervious
Urban
Pervious and Impervious
Urban
Pervious and Impervious
Urban
Pervious and Impervious
Urban
Pervious and Impervious
Urban
Pervious and Impervious
Urban
Pervious and Impervious
27
Urban
Pervious and Impervious
Urban
A quick tour of the Water Quality
Model History….
1998 Continuous 10-yr model
with SAV & benthic filter/
deposit feeders added
1987 SteadyState Version
(584 cells
summer
months only)
1992 Continuous 4-yr
model with dynamic
sediment flux simulation
(5,000 cells)
(12,000 cells)
28
Water Quality and Sediment
Transport Model
• This model
allows assessment
of dissolved
oxygen and
chlorophyll water
quality standards.
• Because of tight
coupling of processes, several of the
integrated models are coupled to the Water
Quality Model, i.e., interacting at every
model time step. The coupled models are the
SAV, oyster, menhaden, and sediment
transport models.
57,000 cells
29
Water Quality Sediment
Transport Model
• The Water Quality Model combined with the Sediment Transport
and filter feeder models allows assessment of the clarity/SAV water
quality standard.
• Sediment Transport Model includes scour of Bay bottom from
current, wave resuspension in the shallows, and detailed shore
erosion estimates.
30
Coupled Living Resource
Models
• The clarity/SAV WQS is for the
restoration of SAV, yet increased SAV
biomass has positive feedbacks on the
improving clarity.
• For more than a decade oysters have been
demonstrated to improve water clarity, particularly in
shallow water - habitat for both oysters and SAV.
• The influence of menhaden
on water clarity has yet to be
demonstrated.
31
Bay WQ/ST Model Includes:
• Circulation/hydrodynamics
• Water Quality: DO, clarity, N, P, sediment
• Algae
• Zooplankton
• SAV
• Oysters
• Benthos
• Menhaden
32
Assessing the Influence of Filter Feeder Living Resources
on Water Quality
33
Living Resource Models of Trophic Interactions
Coupling the Ecopath with Ecosim ecological model to the water
quality model will examine the Bay’s future trophic system when
nutrient loads are about half what they were at their zenith in the
1980s.
34
Climate Change Model
• 2030 climate change - to provide
“conservative model estimates” for
TMDL model of Chesapeake.
• Linked with socio-economic models
of growth and development and
expected 2030 land use change.
Source: Frumhoff et al. 2006 Climate
change in the NE United States
35
Setting the
Pollution Diet
1960s
The Chesapeake Bay Restoration
A Short History - Key Events
•1960s-70s
•1967
•1976-1982
•1980
•1983
•1987
•1992
•2000
•2008
•2010
2011
Visible decline in Bay resources
Chesapeake Bay Foundation established
EPA conducts 5-year Bay study
Chesapeake Bay Commission established
First Bay Agreement - Bay Program created
Second Bay Agreement – WQ Goals
Amendments to Agreement – Tributary Strategies
Third Bay Agreement – Precursor to TMDL
Water Quality Impairments Acknowledged
Chesapeake Bay TMDL established
37
Chesapeake Bay TMDL: December 2010
• Bay TMDL is the most comprehensive roadmap for restoration we
have ever had for Chesapeake Bay.
• Addresses all sectors and major sources of nutrient and sediment
pollution.
• Designed with rigorous accountability measures to ensure that all
pollution controls needed to restore Bay are in place by 2025, with 60
percent (70% MD) by 2017.
• Restoration activities will protect and enhance the economic value of
the Bay and rivers, and be a driver for local economies.
Why a Chesapeake Bay TMDL?




Responds to court orders and legal settlements.
Authorized under Clean Water Act
Chesapeake 2000 Agreement by 2010
Cornerstone of Executive Order
Nitrogen- MD Progress 1985-2010
NOW
1992
Where
we will
be in
2025
2025
Relative Effect of a Pound of Pollution on Bay Water Quality
41
EPA Role in WIP Development
Phase I
Phase II




Provide specific expectations to
support Chesapeake Bay
TMDL
Lead outreach effort on TMDL
Evaluate state strategies in
Phase I WIPs
Establish Chesapeake Bay
TMDL
42

Oversight of Bay TMDL and Phase
I WIP implementation

Support jurisdictions, where
requested, in local outreach effort

Targeted reasonable assurance
evaluation of state strategies

Leave it to states to review
specifics of local strategies

Support jurisdictions in Phase II
WIP development

Refine TMDL allocations as
necessary in late 2012
Bay TMDL and WIP Schedule: 2009-2017
Nov 29, 2010 Final WIPs
Oct 2009
Major basin
jurisdiction
loading
targets
NovemberDecember
2009
Bay TMDL Public
Meetings
Phase I WIP:
November 2009 –
Sept.1 2010
Local Program
Capacity/Gap
Evaluation
July 1 and August 13 Allocations
Draft TMDL
Sept. 24, 2010
(45 days)
Public
Review
And
Comment
December
2010
August 1,
2011
Final
TMDL
Established
Model updates & revised
planning targets
Phase II WIPs:
draft due Dec 15,
2011; final due
Mar 30, 2012
Starting
2011
Divide Target Loads
among Watersheds,
Counties,
Sources
2-year
milestones,
reporting,
modeling,
monitoring
2017 60% of Practices in Place Phase III WIPs to meet 2025 Goal
Phase II WIPs: Taking it local
Phase II WIPs are intended to ensure that local partners
understand their role in meeting TMDL allocations and are
ready to help implement their state’s WIP strategy.
44
Phase II WIP Planning Targets
Jurisdiction
Nitrogen
Phosphorus
Sediment
million lbs/year
million lbs/year
million lbs/year
District of Columbia
2.37
0.12
17
Delaware
3.39
0.28
100
Maryland
41.17
2.81
1350
New York
8.35
0.64
304
Pennsylvania
78.83
3.60
1945
Virginia
52.46
6.46
3251
5.00
0.64
373
191.57
14.55
7341
West Virginia
TOTAL
45
Development of Phase II WIP Planning Targets
• EPA arrived at these planning
targets by running the proposed
reduction strategies in the Phase I
WIPs, adjusted to meet the
12/29/10 Bay TMDL through the
updated Watershed Model.
• Bottom line: Actions needed on
the ground to clean up our
waterways have not changed as a
result of these modeling tool
refinements.
46
Developing a Bay Pollution Diet
Step 1: Quantify per pound impact on Bay water quality.
Step 3: Jurisdictions allocate among sectors (e.g.
Ag, SW, WW) and segment sheds in their WIPs.
Step 4. EPA establishes the Bay TMDL
Step 2: Determine allocation for the major river basins
and jurisdictions by applying the agreed to allocation
methodology.
The resulting dialogues between EPA and the
jurisdictions attempted to take us from
HERE...
…TO
HERE
These discussions have also led to a better understanding of
where our collective approach is working and where we need to
adapt to achieve our common goal of restoring the region’s
waterways.
48
Percent reduction from 2010 noBMPs to E3
100%
90%
80%
70%
TN, p5.2, goal=200, WWTP = 4.5 - 8 mg/l, other: max=min+20%,
Air vs Land
target load controls (% controllable N load)
NOx Deposition Loads
Wastewater Loads
4.5 mg/l
8 mg/l
All other sources
60%
50%
Allocation Method Selected by
Watershed States’ Secretaries
40%
30%
20%
All Other
WWTP
10%
Ammonia Deposition Loads
0%
0
1
2
Air based on 2020 scenario from CMAQ
3
4
5
Relative Effectiveness
6
7
8
9
Nutrient Allocation Decision Support System
Criteria
Assessment
Procedures
Bay
Model
100
90
CFD Curve
80
Percent of Time
Airshed Model
Watershed
Model
70
Area of Criteria
Exceedence
60
50
Area of Allowable
Criteria
Exceedence
40
30
20
10
0
0
10 20 30 40 50 60 70 80 90 100
Percent of Space
Effects
Allocations
50
Scale of Allocations
Major River
Basin
Major River
Basin by
Jurisdiction
Agreed to by the Chesapeake
Bay Program Partners
Jurisdiction
Tributary
Strategy Basin
Partners’
Decision
51