Chesapeake Bay ProgramDecision Support System

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Area of AllowableCriteria

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Management Actions

Watershed Model

Bay Model

CriteriaAssessmentProcedures

Effects

Allocations

Airshed Model

Land UseChange Model

COAST

Annual or Monthly:

Land Use AcreageBMPsFertilizerManureAtmospheric DepositionPoint SourcesSeptic Loads

Hourly Values:

RainfallSnowfallTemperatureEvapotranspirationWindSolar RadiationDewpointCloud Cover

Daily output comparedTo observations

Quick overview of watershed model Calibration

HSPF

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 • Wooded• Disturbed Forest

• 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

Plus Point Source and Septic

Each calibrated to nutrient and Sediment targets

Agriculture40%

Forest15%

Atmospheric Deposition to Non-

Tidal Water1%

Urban & Suburban Runoff18%

Municipal & Industrial

Wastewater21%

Septic5%

Agriculture - manure19%

Agriculture - chemical fertilizer

16%

Agriculture - Atmospheric Deposition - livestock & fertilized soil

emissions6%

Atmospheric Deposition - mobile (on-road + non-

road) + utilities + industries

21%

Natural - lightning + forest soils

1%

Urban & Suburban Runoff - chemical

fertilizer11%

Municipal & Industrial Wastewater

21%

Septic5%

Land Use Source

Ultimate SourceWSM Uses:

Divide Load into contributing areas and sources

From the Chesapeake Bay Commission Report: Cost-Effective Strategies for the BayDecember, 2004

WSM Uses:Determine Effective Practices

WSM Uses:Track Implementation Progress

WSM Uses:Track Implementation Progress

WSM Uses:Track Implementation Progress

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1985 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

TN

(M

illi

on

LB

S/Y

R)

Cap Load Allocation

WSM Uses:Estimate annual loads below monitoring stations

Roughly 25% of the total load is unmonitored

2003 Decision:Reduce annual

loads to 175 million lbs TN and 12.8

million lbs TP

Phase 4

Phase 5 Development

Phase 5

Large Community of Developers

Maryland Department of the EnvironmentVirginia Department of Conservation and Recreation

DevelopersEPA

U of MarylandUSGSNRCS

Chesapeake Research ConsortiumVirginia Tech

Interstate Commission onthe Potomac River Basin

Chesapeake Bay Program

Advisors and data suppliersState Governments of

NY, PA, MD, DE, VA, WV, DCScientific and Technical Advisory Committee

USGS

$

$

$

Phase 4.3 Calibration Phase 5 Calibration

Calibration sites = 20Land Segments = 94River Segments = 94Land uses = 9Simulation Years = 10

Calibration sites = 296Land Segments = 308

River Segments= 1,063Land uses = 25

Simulation Years = 20

Fine Segmentation

ETM Functionality

• Greater Accuracy:– Time Varying Land Use– Time Varying BMPs– BMP efficiency reacting to hydrologic condition – Design life of BMPs– Sub-grid effects (differential land-to-river transport)

• Easier Data Handling– Easily allows large-scale parameter adjustments during

calibration– Parallel computing operations convenient– Easy to add new land use types– Easily integrated into outside databases for scenarios– Relatively easy to add new WQ constituents (bacteria)

Additional CBPO-coded features allow:

Flexible Functionality

Better, extended, and finer scale data sets

High Resolution Input Data

Land Use AcreageBMPsFertilizerManureAtmospheric DepositionPoint SourcesSeptic Loads

RainfallSnowfallTemperatureEvapotranspirationWindSolar RadiationDewpointCloud Cover

Simulation period is 1984-2005: Two decades of meteorology and watershed management data

Open-Source Model• Entire model available on web• Already in Use

– Climate Change Study– Community model at ICPRB– Potomac PCB TMDL– MDE TMDLs– USGS Factors Affecting Trends– USGS Shenandoah Models– Academic studies– UNC / Baltimore LTER study– 60-year ‘Tipping point’

investigation

Transferability

User-Friendliness

• Ensures even treatment across jurisdictions

• Fully documented calibration strategy

• Repeatable

• Makes Calibration Feasible

• Enables uncertainty analysis

Automated Calibration

Chesapeake Bay ProgramDecision Support System

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Management Actions

Watershed Model

Bay Model

CriteriaAssessmentProcedures

Effects

Allocations

Airshed Model

Land UseChange Model

COAST

Nitrogen Pollution and Cost

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Non-attaining water vs annual cost

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Tier3

Drastic Option

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Absolute Effect Normalized by load

Susquehanna

MD Western Shore

Patuxent

Potomac

Rappahannock

York

James

MD Eastern Shore

VA Eastern Shore

Estuarine model used to determine basins with highest effect on DO

Incr

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Effect of Geographic Targeting

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Tier3

Drastic Option Efficient Option

WatershedStates

Responsibility

Nitrogen-Phosphorus-Sediment

Load Allocation Process

By 9 major river basins

...then by 20 major tributary basins by

jurisdiction

…then by 44 state-defined tributary

strategy subbasins

WatershedPartners

Responsibility

WatershedStates

Responsibility