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Watershed Implementation Plan Tools

The following is a collection of resources to aid in the creation, implementation and understanding of the Watershed Implementation Plans (WIPs).

Best Management Practices Tools:

Modeling Tools:

Other Supporting Materials:

Best Management Practices Tools

Nutrient and Sediment Control Review Protocol

Best Management Practices (BMPs) will play a vital role in the restoration of the Bay.

Crediting Nutrient/Sediment Reductions from Agricultural Conservation Practices in the Chesapeake Bay Watershed Model

The U.S. EPA has developed a fact sheet which provides answers to frequently asked questions regarding how the Chesapeake Bay Program partnership credits agricultural conservation practices and the associated nutrient and sediment reductions in the Chesapeake Bay Watershed Model.

Nutrient and Sediment Control Review Protocol

The Protocol for the Development, Review, and Approval of Loading and Effectiveness Estimates for Nutrient and Sediment Controls in the Chesapeake Bay Watershed Model  describes the process a BMP must go through to be approved. Best Management Practices (BMPs) will play a vital role in the restoration of the Bay. For a table depicting the BMPs identified for review, as well as the status of the practice’s review, please visit ChesapeakeStat.

Scenario Builder BMPs, Land Uses, and Processes

The Scenario Builder tool and the Chesapeake Assessment Scenario Tool (CAST) use the same land uses, BMPs and BMP effectiveness values.  Descriptions of each BMP, land use, and processes for how the BMPs are credited can be found at: http://casttool.org/Documentation.aspx.

Mid-Atlantic Water Program BMP Report

This report, Developing Best Management Practice Definitions and Effectiveness Estimates For Nitrogen, Phosphorus and Sediment in the Chesapeake Bay Watershed , includes nutrient and sediment reduction effectiveness estimates of select agricultural, stormwater and forestry BMPs. With funding from the Chesapeake Bay Program Office, the University of Maryland Mid-Atlantic Water Program developed definitions and effectiveness estimates for BMPs that states were implementing or proposing to implement as part of their efforts to meet the nutrient and sediment reduction goals necessary to restore the Bay. The report provides realistic, science-based estimates of expected nutrient and sediment reduction performance from these BMPs and reflects current research and knowledge as well as average operational conditions representative of the entire Chesapeake Bay watershed.

Assessment and Scenario Tools (CAST, MAST, VAST, and BayFAST)

The Chesapeake, Maryland, and Virginia Assessment and Scenario Tools (CAST, MAST, VAST, and BayFAST) allow users to rapidly develop scenarios with varying best management practices. Output includes nitrogen, phosphorus, and sediment loads from all sectors and sources and the acres of each BMP for any area in the Chesapeake Bay Watershed. These loads are consistent with the Chesapeake Bay Program’s Watershed Model. CAST, MAST, and VAST also provide inputs to the Chesapeake Bay Program computer models. BayFAST allows users to rapidly develop scenarios with varying best management practices. BayFAST allows users to define their parcel boundaries and land uses.

Users can compare among scenarios to select the practices that reduce the most pollution and target these practices to the highest impact areas. Scenarios can be used for TMDL Watershed Implementation Plans, Milestones, or for local planning purposes.

Modeling Tools

The Chesapeake Bay Program uses many models to guide its decisions and approach. The following materials show these tools and their outputs.

Chesapeake Bay Program Model Phase 5

Access Phase 5.3 Watershed Model input decks and outputs for information on land uses, BMP implementation, and edge-of-stream and delivered nutrient and sediment loads for key scenarios. Information is available by state, major basin, county, or land-river segment. Please refer back to this ftp site often for any new or updated files and contact Sucharith Ravie if you have questions.

Access Phase 5.2 Watershed Model loads, landuse acres, and BMP implementation data for key scenarios including 1985, 2002, 2008, 2010 Tributary Strategy, 2010 E3, and 2010 No-Action.

FTP Site

As of June 2, 2010, the Phase 5.3 version of Chesapeake Bay watershed model is available for download at ftp://ftp.chesapeakebay.net/Modeling/phase5/community/P53/.  Please follow the steps outlined in the README file as you carry out your download.  Since the Bay Program has made several changes to the model code and has run scripts since June 2, please re-download the run scripts and model code to keep up with the latest developments if you downloaded Phase 5.3 prior to that date.

Phase 5.3 Watershed Model Scenario Submissions

The Bay states and D.C. must use the following template when submitting Phase 5.3 Watershed Model scenario requests. The template and instructions are subject to change as new BMPs are added and approved and future phases of Scenario Builder are developed, so please refer back to this site for the most recent documents.

An input deck template, instructions, and example Scenario Builder input decks and outputs for 2009 Progress, 2010 Tributary Strategy, and 2010 E3 are available at ftp://ftp.chesapeakebay.net/Modeling/phase5/Phase53_Loads-Acres-BMPs/. The example inputs and outputs show the complete distribution of BMPs across all landuse types in relevant units (i.e., acres, feet, etc.) at the most detailed scale of land-river segments.

Scenario Builder

Scenario Builder is a computer tool that can generate simulations of the past, present or future state of the watershed to run through the Chesapeake Bay Watershed Model. This allows for the exploration of potential impacts of management actions and evaluation of alternatives.

Scenario Builder simulations are based on factors from a wide range of land uses and restoration activities. Using agriculture as an example, information such as acres of different crops, numbers of animals and extent of conservation practices is used to generate Watershed Model inputs of for agricultural land use types.

In support of the Chesapeake Bay Program's ongoing commitment to scientific integrity, openness and transparency in its computer models and Chesapeake Bay TMDL development, several components of Scenario Builder are provided. These include the programming code for Scenario Builder and the input decks and outputs for the states' draft Phase I Watershed Implementation Plans, Hybrid Backstop TMDL and Full Backstop TMDL. The scenario builder documentation references the information and decisions used in creating this modeling tool used by the Chesapeake Bay Program Partnership for decision making.

Model Segmentation Viewer

The segmentation viewer allows partners to overlay Phase 5 Watershed Model Segments with layers including streets, satellite imagery, shaded relief, MS4 areas, 12-digit watersheds, and counties. This tool will allow local planners the ability to see and verify where specific segments are in relation to other boundaries and features, aiding in the decision-making process.

Relative Effectiveness Factors

Download spreadsheet for the relative effectiveness factors used in Phase 5.3.

Effectiveness Shapefile

This shapefile was used to create Maps of the Nitrogen and Phosphorus Effectiveness throughout the Watershed (10/2009). Please direct any questions to Guido Yactayo at gyactayo@chesapeakebay.net.

MS4 Shapefile

The MS4 Shapefile, as well as related information can be found at the link provided below. This shapefile is the file used to map the MS4s within the Bay watershed. Note: the file found at this link may periodically change. Please check back on a regular basis for the most up-to-date files. Please direct any questions to Guido Yactayo.

Federal Land Shapefile

The Federal Lands Shapefile and related information can be found at the link provided below. This shapefile is the file used to map Federal Lands within the Bay watershed. Note: the file found at this link may periodically change. Please check back on a regular basis for the most up-to-date files. Please direct any questions to Guido Yactayo.

Other Supporting Materials

The documents provided below include the expectations and consequences associated with this process, as well as guidance information.

Guides for Phase II Watershed Implementation Plans


The following letters provide information from EPA to the jurisdictions regarding the TMDL:

Information on EPA's Evaluation of Watershed Implementation Plans

A Guide for EPA’s Evaluation of Phase I Watershed Implementation Plans includes details on how EPA will review and evaluate the Chesapeake Bay TMDL Phase I Watershed Implementation Plans submitted by each of the states and the District of Columbia. For contact information, please consult this list of WIP Evaluation Team Leads.

Local Watershed Implementation Plan Pilot Projects

A recurring theme at meetings is the need for more cutting-edge research and new technologies. EPA is providing funding to pilot projects to begin to conduct needed research and explore untapped options. This document summarizes the process already underway.

Tributary Strategies

The Tributary Strategy plans to reduce pollution to the Chespeake Bay have been replaced by the state-developed Watershed Implementation Plans (WIPs), available on this webpage, and a federal Total Maximum Daily Load (TMDL).


Tributary strategy


http://archive.chesapeakebay.net/pubs/NanTAT_Recommendations.pdf | http://archive.chesapeakebay.net/pubs/UpperChesapeakeTAT_Recommendations.pdf

District of Columbia

http://archive.chesapeakebay.net/pubs/DC Tributary Strategy 2004_public_version_071204.pdf



New York



http://archive.chesapeakebay.net/pubs/PA tribstrategy 2004.pdf


http://archive.chesapeakebay.net/pubs/VA ts_statewide_All 2005.pdf

West Virginia


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