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Phase 5.3 Watershed Model

Phase 5.3 is the latest version of the Chesapeake Bay Program's Watershed Model.

A number of improvements are being made from the previous version of the model, Phase 4.3. The most significant improvement is the scale in which the data are now available. The Phase 5.3 Watershed Model can be used at the Chesapeake watershed scale as well as smaller scales for state-developed TMDLs. This will allow watershed load analysis to be consistent between state-led basin and small tributary TMDLs and the Bay Program-led assessment of overall Chesapeake Bay water quality.

Specific improvements include:

  • Refined and updated rainfall, fertilizer, best management practice (BMP) and landscape processes data. All data will be updated to 2002, allowing a 20-year simulation period from 1984 to 2005.
  • Refined segmentation of land segments and river reaches, including the simulation of major reservoirs in the watershed.
  • Additional land use simulations. There are more than 20 Phase 5.3 land uses, a two-fold increase from Phase 4.3. Phase 5 land uses include 12 different crop types and several new BMPs such as CAFOs, surface mines and construction sites.

The collaboration between the U.S. Environmental Protection Agency, the Chesapeake Bay Program, U.S. Geological Survey, Interstate Commission on the Potomac River Basin, Maryland Department of the Environment, Virginia Department of Conservation and Recreation, and the University of Maryland has allowed the Bay Program to significantly improve the spatial and computational scale of the model.

For more information, view the Bay Program’s model-related publications. Featured publications include:

Phase 5.3 Community Model Documentation

The Phase 5.3 model documentation is provided below. This documentation includes updates in October 2006, January 2007, April 2007, July 2007 and February 2010.

These reports should be cited as "USEPA (U.S. Environmental Protection Agency). 2010. Chesapeake Bay Phase 5.3 Community Watershed Model. EPA 903S10002 - CBP/TRS-303-10. U.S. Environmental Protection Agency, Chesapeake Bay Program Office, Annapolis MD. December 2010."

Section 1: Watershed Model Overview (Download)

Section 2: Meteorology and Precipitation (Download)

Section 3: Land and River Segmentation (Download)

Section 4: Land Use (Download)

Section 5: Non Point Source Nutrient Inputs (Download)

Section 6: Best Management Practices (BMP) (Download)

Section 7: Point Sources, Water Withdraws, and On-Site Waste Disposal Systems (Download)

Section 8: Hydrology Simulation (Download)

Section 9: Sediment Simulation (Download)

Section 10: Non Point Source Simulation (Download)

Section 11: Riverine Simulation (Download)

Section 12: Key Scenarios and Findings (Download)

Section 13: Community Model (Download)

Phase 5.3 Model Calibration Information (42.5MB)

Scenario Builder Documentation

Scenario Builder Documentation

Latest Draft

 

Download

Phase 5.3 Watershed Model Calibration Output Data

Phase 5.3 Watershed Model Calibration Input Data

Non-Point Source Nutrients

Fertilizer

The comma-separated values files within this zip directory contain input loads from fertilizer to the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. The loads of different species (organic nitrogen and phosphorous, nitrate, ammonia and phosphate) are displayed by land segment and land use.

The data is organized as follows: Land Segment, Land Use, Species (nh3n, orgp etc.), Load (lbs/acre) by month

Manure

The comma-separated values files within this zip directory contain input loads from manure to the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. The loads of different species are displayed by land segment and land use.

The data is organized as follows: Land Segment, Land Use, Species (nh3n, orgp etc.), Load (lbs/acre) by month

Legumes

The comma-separated values files within this zip directory contain input loads from legumes to the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. The loads of different species are displayed by land segment and land use.

The data is organized as follows: Land Segment, Land Use, Species (nh3n, orgp etc.), Load (lbs/acre) by month

Septic

The comma separated values file septic_p53cal_allyears.csv contains estimated septic load for each land-river segment in pounds per day.

Crop Cover

The comma-separated values files within this zip directory contain crop cover data for the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. Crop cover percentages are displayed by land segment and land use.

The data is organized as follows: Land Segment, Land Use, Crop Cover % by month

Land Use

The comma-separated values files within this zip directory contain land use data for the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. Acres of each land use are displayed by land-river segment.

The data is organized as follows: River Segment, Land Segment, Land Use (Acres), Best Management Practices (BMPs)

BMP Pounds

The comma-separated values files within this zip directory contain BMP data for the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. Reductions in pounds are displayed for each combination of land-river segment, BMP, land use type, and constituent (ex. total nitrogen). Please note that the 1985 and 1987 files are empty.

The data is organized as follows: River segment, Land Segment, BMP Shortname, Landuse_Type, Constituent, Pounds

BMP Acres

The comma-separated values files within this zip directory contain BMP data for the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. Acres of each BMP are displayed for each combination of land-river segment, BMP, land use type, and constituent (ex. total nitrogen).

The data is organized as follows: River segment, Land Segment, BMP Shortname, Landuse_Type, Acres Uptake

Maximum Uptake

The comma separated values files within this zip directory contain maximum uptake data for the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. Maximum uptake in pounds per year is listed for each land segment, land use, and constituent (nitrogen or phosphorous).

The data is organized as follows: Land Segment, Land Use, Constituent (N or P), Maximum Uptake (lbs/yr)

Uptake Curve

The comma-separated values files within this zip directory contain uptake curve data for the Phase 5.3 Watershed Model Calibration for the years 1985, 1987, 1992, 1997, 2002 and 2005. The uptake curve is displayed as a decimal fraction for each land segment, land use, constituent (nitrogen or phosphorous), and month.

The data is organized as follows: Land Segment, Land Use, Constituent (N or P), Uptake fraction by month

Atmospheric Deposition

The Excel worksheets provided summarize annual and monthly average atmospheric deposition for each model land segment (i.e., county) for 1984-2005.

Non-point Source Best Management Practices (NPSBMP) Exchange Network Data Flow

The Chesapeake Bay Program operates a node on the Environmental Information Exchange Network, and, through this node, receives NPSBMP implementation data from Program partners. Scenario Builder can then use the data when producing inputs for the Watershed Model. Below is the documentation for this data flow.

Schema:

Additional Documents:

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