Projecting Chesapeake Bay Watershed Conditions

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ProjectingChesapeake Bay Watershed Conditions

• Jeffrey S. Sweeney
• University of Maryland
• Chesapeake Bay Program Office
• jsweeney_at_chesapeakebay.net
• 410-267-9844
• Developing Alternative Land Use and Nutrient
  Source Scenarios for the Chesapeake Bay Phase V
  Watershed Model
• Smithsonian Environmental Research Center
• February 7, 2006

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Chesapeake Bay ProgramCurrent Modeling Structure
Nitrate and ammonia deposition from Regression
Model (NADP concentrations, precipitation, time,
and latitude) applied to precipitation data from
gauging stations. Adjustments to deposition
from Regional Acid Deposition Model (RADM)
Chesapeake Bay Estuary Model Package Hydrodynamic
Model, Sediment Benthic Model, and Submerged
Aquatic Vegetation
Chesapeake Bay Watershed Model Lumped-parameter,
physically-based Land and water simulation,
Nutrient and sediment simulation
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Chesapeake Bay ProgramNew Modeling Structure
Nitrate and ammonia deposition from improved
Daily Nitrate and Ammonium Concentration
Models Adjustments to deposition from
Models-3/Community Multi-scale Air Quality
(CMAQ) Modeling System
Phase 5 Watershed Model Better year-to-year
simulation mass balance modeling Large
aggregate land simulation with distributed
rivers Time series of management practices
Automated calibration
Chesapeake Bay Estuary Model New grid Bank
loads Nutrient controls on TSS and chlorophyll-a
sinking/suspension Hydrodynamic and Wave Models
for sediment re-suspension in the Water Quality
Model
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Needed Components for ProjectionsChesapeake Bay
Program Watershed Model

• Landuses
• Agriculture
• Urban
• Extractive
• Construction
• Forest
• Natural Grass
• Nutrient Inputs to the Land
• Manure Applications and Excretions
• Animal Populations
• Chemical Fertilizers
• Agricultural
• Non-Agricultural
• Atmospheric Deposition
• Point Sources
• Septic
• Best Management Practices

Need the ability to evaluate the long-term
effectiveness of tributary strategies to
reduce nutrients and sediment. Need to
quantify and credit the nutrient load reduction
benefits from land use planning and land
preservation.
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Needed Components for ProjectionsChesapeake Bay
Program Watershed Model

• Landuses
• Agriculture
• Urban
• Extractive
• Construction
• Forest
• Natural Grass
• Nutrient Inputs to the Land
• Manure Applications and Excretions
• Animal Populations
• Chemical Fertilizers
• Agricultural
• Non-Agricultural
• Atmospheric Deposition
• Point Sources
• Septic
• Best Management Practices

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Chesapeake Bay WatershedModeled Landuses
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Phase 4.3 Watershed Model 2010 Agricultural
Landuse Projections
What best reflects what is expected to occur?
Long-term Ag Census trend (two points 82 97)
Short-term Ag Census trend (two points 92
97) Linear regression of four Ag Census years
Average of regressions four Ag Census years and
short-term Ag Census trend
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Phase 4.3 Watershed Model 2010 Agricultural
Landuse Projections
What best reflects what is expected to occur?
Short-term Ag Census trend (two points 92
97) Average of regressions four Ag Census
years and short-term Ag Census trend
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Phase 4.3 Watershed Model 2010 Urban Landuse
Projections
Urban Land Forecast Non-MD Jurisdictions
Urban land area increased at the same rate as
projected population increases. MD Applied
DNR/MDP 2000-2010 urban growth data.
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Phase 4.3 Watershed Model 2010 Forest and Mixed
Open Landuse Projections
Forest and Mixed Open Land Forecast MD
Applied forest loss data from the state. VA
Applied forest loss method from the state.
Other jurisdictions Forest and mixed open were
the defaults from agricultural and urban
changes.
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Needed Components for ProjectionsChesapeake Bay
Program Watershed Model

• Landuses
• Agriculture
• Urban
• Extractive
• Construction
• Forest
• Natural Grass
• Nutrient Inputs to the Land
• Manure Applications and Excretions
• Animal Populations
• Chemical Fertilizers
• Agricultural
• Non-Agricultural
• Atmospheric Deposition
• Point Sources
• Septic
• Best Management Practices

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Phase 4.3 Watershed Model 2010 Animal Projections
What best reflects what is expected to occur?
From state agencies/animal industry experts.
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Phase 4.3 Watershed ModelAnimal Nitrogen
Generation
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Phase 4.3 Watershed ModelAnimal Manure Mass
Balance
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Needed Components for ProjectionsChesapeake Bay
Program Watershed Model

• Landuses
• Agriculture
• Urban
• Extractive
• Construction
• Forest
• Natural Grass
• Nutrient Inputs to the Land
• Manure Applications and Excretions
• Animal Populations
• Chemical Fertilizers
• Agricultural
• Non-Agricultural
• Atmospheric Deposition
• Point Sources
• Septic
• Best Management Practices

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Needed Components for ProjectionsChesapeake Bay
Program Watershed Model

• Agricultural Chemical Fertilizers
• Phase 4.3 Pre-nutrient management application
  rates from state agricultural experts that are
  adjusted in the model according to peer-reviewed
  nutrient management rules ? reduction of chemical
  fertilizer applications as reported plan
  implementation increases Assumes both N- and
  P-based nutrient management.
• Phase 5 Chemical fertilizer applications rooted
  in sales data Assumes N-based nutrient
  management for calibration period and will
  account for P-based when reported.
• Non-Agricultural Chemical Fertilizers
• Phase 4.3 Assumes 50 pounds N/acre application
  rate on all pervious urban and 12.5 pounds N/acre
  on mixed open No P applications to urban or
  mixed open lands.
• Phase 5 Chemical fertilizer applications rooted
  in sales data Incorporates P applications to
  urban land.

Chemical Fertilizer Nitrogen Applications to the
Chesapeake Bay Watershed Phase 4.3 Watershed Model
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Needed Components for ProjectionsChesapeake Bay
Program Watershed Model

• Landuses
• Agriculture
• Urban
• Extractive
• Construction
• Forest
• Natural Grass
• Nutrient Inputs to the Land
• Manure Applications and Excretions
• Animal Populations
• Chemical Fertilizers
• Agricultural
• Non-Agricultural
• Atmospheric Deposition
• Point Sources
• Septic
• Best Management Practices

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Chesapeake Bay Watershed Model Atmospheric
Deposition Projections

• Nutrient Inputs to the Land
• Atmospheric Deposition
• Phase 4.3 Projections out to 2020 with various
  levels of regulatory (Clean Air Act) and
  voluntary emission controls on utility, mobile,
  and industrial sources.
• Phase 5 Projections out to 2030 with various
  levels of regulatory (Clean Air Act) and
  voluntary emission controls as well as past
  trends in deposition.

Nitrogen Deposition to the Chesapeake Bay
Watershed Phase 4.3 Watershed Model
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Chesapeake Bay Watershed Model Point Source
Projections

• Point Sources
• Phase 4.3 Projections out to 2010 with various
  levels of effluent concentrations and forecasted
  flows from facilities.
• Phase 5 Projections out to 2030 with emphasis
  on attainment and maintenance of permit limits,
  but need projection of flows from sewer-sheds.

Point Source Nitrogen Loads to the Chesapeake
Bay Phase 4.3 Watershed Model
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Chesapeake Bay Watershed Model Septic Projections

• Septic
• Phase 4.3 Projections out to 2010 based on
  human population increase, 1990 U.S. Census
  Bureau data for people on septic, and literature
  values for loads per person.
• Phase 5 Ideally, projections out to 2030 would
  be mass balance knowing human generation of
  nutrients and loads to waste treatment
  facilities.

Septic Nitrogen Loads to the Chesapeake Bay Phase
4.3 Watershed Model
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Needed Components for ProjectionsChesapeake Bay
Program Watershed Model

• Landuses
• Agriculture
• Urban
• Extractive
• Construction
• Forest
• Natural Grass
• Nutrient Inputs to the Land
• Manure Applications and Excretions
• Animal Populations
• Chemical Fertilizers
• Agricultural
• Non-Agricultural
• Atmospheric Deposition
• Point Sources
• Septic
• Best Management Practices

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Tributary Strategy Agricultural, Urban and Mixed
Open BMPs
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Tributary Strategy Forestry, Septic and
Shoreline BMPs
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Needed Components for ProjectionsChesapeake Bay
Program Watershed Model

• Landuses
• Agriculture
• Urban
• Extractive
• Construction
• Forest
• Natural Grass
• Nutrient Inputs to the Land
• Manure Applications and Excretions
• Animal Populations
• Chemical Fertilizers
• Agricultural
• Non-Agricultural
• Atmospheric Deposition
• Point Sources
• Septic
• Best Management Practices

Need the ability to evaluate the long-term
effectiveness of tributary strategies to
reduce nutrients and sediment. Need to
quantify and credit the nutrient load reduction
benefits from land use planning and land
preservation.
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Purposes of the Chesapeake Bay ProgramWatershed
Model

• Measure the environmental effects of particular
  management schemes for planning purposes.
• Whats the impact of BMP implementation on
  nitrogen, phosphorus, and sediment loads?
• Results help direct tributary strategy
  development
• What yields the biggest bang and the biggest bang
  for the buck?
• Load allocations
• Equitably account for all load sources TMDL
• Measure of loading cap maintenance TMDL
• Provide loads to the Estuary Model
• Whats the impact of BMP implementation on living
  resources/water quality?
• What yields the biggest bang and the biggest bang
  for the buck?
• Attainment of water quality standards in the
  Chesapeake Bay will be determined by tidal water
  monitoring data, not the models.
• Remove impairments by 2010