Virginia Assessment Scenario Tool VAST Developed by: Interstate Commission on the Potomac River Basin.

Virginia Assessment Scenario Tool

VASTDeveloped by:

Interstate Commission on the Potomac River Basin

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VALUE FOR JURISDICTIONS

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• Builds load reduction strategies (by local area) • Identifies the BMPs that give the greatest

load reductions• Specifies the extent these BMPs are to be

implemented

• Meets the allocations• Compares among scenarios

• Produces CBP Scenario Builder model inputs

• Assesses WIPs and 2-Year Milestones

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VAST FEATURES• Is Replicable , Consistent, and Transparent

– Consistent with EPA Phase 5.3.2 and WIP Phase II

• Available/approved load reduction practices with efficiencies– Continuous no-till is calculated differently than the

Chesapeake Bay Program

• Serves as a data management system

• Facilitate stakeholder involvement, teach stakeholders implications of decisions

• Facilitate an adaptive process, scenario development is iterative

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PLANNING YOUR SCENARIOWhat do I need to know?

• Chesapeake Bay Program vocabulary– Land Use names– BMP names

• Initial idea of which BMPs you want to implement – VAST will help you refine BMP choices

You don’t have to know how the BMPs are calculated.

• VAST does the calculations for you.• Documentation on the website steps through all the

BMPs calculations.1/6/2012 4

VAST OUTPUTS• Land use acres available

• Changes in the acres of each land use

• BMPs submitted – Lists the BMPs in your scenario– Shows your notes for each BMP. The notes field is your

justification. – Shows which BMPs it was not possible to credit

• Loads for each land use – Edge of stream (EOS)– Delivered to the Chesapeake Bay (DEL)

• Inputs to the Chesapeake Bay Program’s Scenario Builder1/6/2012 5

DATA INPUT SEQUENCE

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LOG IN

SCENARIO LIST

URBAN BMPs

SEPTICBMPs

WASTE WATER

FOREST BMPs

ANIMAL BMPs

MANURE TRANSPORT

AGRICULTURAL BMPs

SUMMARY

SCENARIODETAILS

COMPARE SCENARIOS

VASTTOOL.ORG

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FINE TUNE TO MAXIMIZE REDUCTIONS• Calculations and the sequence in which they are done are critical—

And VAST does them for you!

• Target implementation to areas where the pre-BMP load and the delivery to the Bay is highest

• Land use change BMPs provide more of a reduction than effectiveness value BMPs because they are always calculated before effectiveness value BMPs, where the pre-BMP load is similar– Effectives BMPs are calculated after the land use changes, so prioritize land use

change BMPs since they will be applied to the greater portion of land

• Where BMPs are mutually exclusive (in the same group in the table, such as with NM), prioritize the BMP in the group with the higher effectiveness.– Nutrient Management– Stormwater practices– Cover crops 81/6/2012

• General Features and Users Guide– Available via the link on the

VAST website

• BMP Definitions

• Chesapeake Bay Program Land Use Definitions

• BMP Calculation Sequence and Groups

• BMP effectiveness values by land use and HGMR and pollutant

• And more.

REFERENCE MATERIAL

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FUTURE REFINEMENTS• Users input acres or percent implementation

• BMP costs

• Data Quality– P on AFO/CFO– Improved estimation of animal BMPs– Additional testing

• Speed—upgrade tool to accommodate increased usage, larger scenarios

• Show results as percent implementation, not just loads

• Continued technical support and updating documentation

1/6/2012

Olivia DevereuxInterstate Commission on the Potomac River Basin/

Potomac Valley Conservancy District301-274-8114

[email protected]

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VIRGINIA’S PHASE II APPROACHLOCAL DELIVERABLES & DEADLINES

• Desired local deliverables– Current BMPs

• Update progress in current model– Land Use / Land Cover

• Work with EPA for use in Phase 6 model– 2017/2025 BMP Scenarios– Strategies to implement BMP scenarios– Resource needs

• Final opportunity to submit data – Deadline – 2/01/2012– Incorporation into Final WIP II

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ASSESSING OUTPUT• The Chesapeake Bay Program’s Watershed Model

has some illogical loadings in some locations in Virginia

• Use of some BMPs can increase loads in these locations– Nutrient management in Loudoun and Henrico, among

others

• VAST models the BMPs the same as the Chesapeake Bay Program, so the results may seem illogical

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GEOGRAPHICAL AREAS NOT ENTIRELY WITHIN THE CHESAPEAKE BAY WATERSHED

• The tool models the state’s portion of the Chesapeake Bay Watershed.

• The percent implementation the user enters is only for the land use area or number of animals shown in the Pre=BMP table on the left of the BMP screen.

• The Pre-BMP land use table shows only the portion of the geographical area within the Watershed

• The animals and manure transport pages show the number of animals in the entire county (data is not available at a finer scale)

• BMPs entered on the animal pages are applied to the entire number of animals in the county.

• Manure transport is applied proportionally to the portion of the county in the Watershed1/6/2012 14