Agricultural BMP Expert Panels
CompleteBMP Expert Panel reports for Agricultural BMPs
Description
BMP Expert Panels are convened to develop the BMP effectiveness estimates and the Water Quality Goal Implementation Team (WQGIT) is responsible for approving the loading rate reductions, and percentage adjustments to these rates, used in the Chesapeake Bay Watershed Model.
Throughout time, the AgWG has been involved in a variety of Expert Panels and related studies to evaluate agricultural BMPs. This page is intended to provide the AgWG with easy access to resources related to agricultural BMPs and BMP expert panels.
Below you will find a list of Expert Panels that the Agriculture Workgroup has been involved with. The underlined title of each practice links to the relevant Expert Panel report. A description of each Expert Panel is also provided and, where applicable, recommendations are listed for both Phase 5 and Phase 6 Expert Panels. The "Project Resources" panel includes additional resources related to Expert Panels. Resources include: BMP Quick Reference Guide; a report from Simpson and (Weammert) Lane (2009) which served as a model for the current BMP Protocol/expert panel process and defines various BMP and effectiveness values; a link to the BMP Expert Panel page documenting all BMP Expert Panels; and a spreadsheet (created March 2026) summarizing BMPs and the last time they were evaluated for credit, as well as a breakout of potential opportunities for remote sensing verification of agricultural BMPs.
Expert Panels Supporting Currently Credited Agricultural BMPs
Agricultural Stormwater Management
The Agricultural Stormwater Management Practices Expert Panel Establishment Group (EPEG) was formed to determine if there is a need for an Agricultural Stormwater Management BMP Expert Panel. It was recommended by the EPEG that the AgWG approach crediting of agricultural stormwater practices (ASP) based on the stormwater treatment adjustor curves for TN, TP and TSS provided in the Urban Stormwater Workgroup Expert Panel Report on defining removal rates for new state stormwater performance standards, with modifications for the agriculture sector. Given the pre-existing Urban Stormwater Workgroup (USWG) recommendations, it was determined that a BMP Expert Panel to address agricultural stormwater management was not necessary. The EPEG recommends a 10-year credit duration for ASP BMPs with verification by multi-year visual assessment, as well as field inspections to be conducted at least every 5 years to maintain credit. Management practices such as ponds, constructed wetlands, and grass swales (often configured in a treatment train) that are designed, constructed, and maintained to treat stormwater from confined animal production facilities, are eligible for credit in the Model.
The Forestry Workgroup and the Agriculture Workgroup convened an Expert Panel Evaluation Group (EPEG) to evaluate whether Silvopasture and Alley Cropping practices should be credited by the Bay Program for their water quality benefits. The EPEG recommended crediting these practices as efficiency BMPs based on the credit that would be received from converting 25% of the agricultural lands where the practice is applied into forest. The EPEG recommended crediting these practices without the formation of an Expert Panel because the approach is based on partnership approved forested land use loading rates.
This Expert Panel was charged with defining and configuring the Animal Mortality Management Best Management Practice (BMP) for use in the Phase 6.0 Chesapeake Bay Watershed Model. Specifically, the panel was charged with defining the load reduction efficiencies for Nitrogen and Phosphorus for selected mortality management methods and determining how the practice can be represented in the model. The panel looked in depth at the following mortality disposal methods: Animal mortality disposal by landfill or rendering; Animal mortality disposal by burial; Animal mortality disposal by incineration; and Animal mortality disposal by composting. As a result of the Panel recommendations, the previously existing Mortality Composters BMP was replaced with the new Animal Mortality Disposal by Composting practice and the planning-only BMP for broiler mortality freezers was eliminated and replaced in favor of the rendering BMP.
Animal Waste Management Systems
The Animal Waste Management System (AWMS) expert panel convened in March 2016 and was instructed to evaluate the existing assumptions of manure lost and manure recovered for each animal type in the Chesapeake Bay Watershed Model and the potential benefits of storage best management practices represented by the AWMS BMP. The panel did not recommend changes to the Phase 5 reporting elements of the AWMS BMP as part of these Phase 6 recommendations (i.e. states report each AWMS system implemented, and animal type/group associated with it if known).
The Agricultural Ditch Management BMP Expert Panel convened in 2016 to review the available science on the nutrient and sediment removal efficiencies associated with agricultural ditch best management practices of particular concern to the Delmarva Peninsula but applicable across the Chesapeake Bay watershed. The BMPs recommended by the panel for purposes of nutrient and sediment reductions in the Phase 6 Watershed Model are as follows: Blind inlets; Blind inlets w/ P-sorbing materials; Denitrifying Bioreactors; Monitored Denitrifying Bioreactor for spring or seep; Drainage Water Management; P removal systems; Monitored P removal system; and Saturated buffers.
Phase 6: This Expert Panel proposes that the Chesapeake Bay Program’s existing definitions and credits associated with implementation of Conservation Tillage be replaced by four new categories of conservation tillage best management practices that are defined primarily by soil residue cover and soil disturbance. Three of these categories represent reductions in tillage compared to conventional/high tillage, which is considered the baseline. Any tillage routine that does not achieve 15 percent crop residue coverage immediately after planting is considered conventional tillage and does not qualify as a BMP. Definitions of these practices are listed in the Technical Appendix (Page 27 of the Expert Panel Report).
Phase 5.3.2 (Recommendations linked here): The Conservation Tillage Expert Panel evaluated/recommended revised tillage practice of Continuous High Residue, Minimum Soil Disturbance, including a new practice definition and efficiency estimates for inclusion in the Phase 5.3.2 of the Chesapeake Bay Program Watershed Model. The report was approved and enacted for 2013 progress by the Water Quality Goal Implementation Team on October 15, 2013. This practice represents the highest level of soil conservation and soil cover management to improve soil organic matter content and soil quality, and to reduce runoff and sediment and nutrient losses. This practice was proposed to provide stackability with other best management practice (BMP) reductions, such as cover crops and nutrient management.
Phase 6: A Phase 6 Cover Crop Expert Panel was formed to address three primary modifications/additions to previous Panel recommendations (Review of nutrient removal efficiencies of the grass/legume mixture cover crop category; Expansion of the traditional cover crop BMP to include cropland where manure is applied in the fall following harvest of the summer crop; Review of the commodity cover crop BMP, which was not addressed by the previous Panel). The panel recommended three types of cover crop practices for credit in the Phase 6 Model: Traditional Cover Crop, Traditional Cover Crop with Fall Nutrient Applications, and Commodity Cover Crop.
Phase 5.3.2 (Report linked here): The previous 2007 cover crop practice was revised in 2015 for the Chesapeake Bay Program Watershed Model Phase 5.3.2 to include new cover crop species, as well as cover crop mixtures, in order to capture Cover Crops January 2017 the diversity and extent of current cover crop practices being used in the Chesapeake Bay Watershed. Additional cover crops proposed in Phase 5.3.2 include Annual Ryegrass, Annual Legumes, Annual Legume plus Grass Mixtures Brassica (winter hardy), Forage Radish, Forage Radish plus Grass Mixtures, Triticale, Oats (winter hardy), and Oats (winter killed).
The Manure Treatment Technologies Expert Panel convened in December 2014 and worked to evaluate the nutrient reduction benefits associated with the various categories of manure treatment technologies, specifically: 1. Thermochemical Conversion 2. Composting 3. Anaerobic Digestion 4. Settling 5. Mechanical Solid-Liquid Separation 6. Wet Chemical Treatment. Manure Treatment BMPs are defined by the expert panel as technologies designed to alter manure characteristics to achieve one or more of the following goals: separate waste streams into a high and a low solids stream; alter manure organic matter; extract energy from manure organic matter; alter the form or concentration of plant-available nutrients; or concentrate nutrients and stabilize organic matter. Manure Treatment is broken into 19 distinct BMPs based upon the type of treatment technology that can be reported for nitrogen reductions. View Table A.1 (Page 25 of the EP Report) for the full list of manure treatment BMPs eligible for credit.
Manure Incorporation and Injection
The Phase 6 Manure Injection & Incorporation (MII) Expert Panel provided the Bay Program with revised definitions and credits for manure injection and incorporation practices. Specifically, the panel recommended that existing definitions associated with MII be replaced by the three new annual manure injection and incorporation practices (Manure injection, manure incorporation high disturbance, and manure incorporation low disturbance). Phase 5.3.2. previously recognized manure injection as a BMP used for planning purposes. As part of the recommendations, the AgWG approved a proposed amendment to the initial P reduction value that would shift the reduction credit from 0% to 12% for P loss reduction in high disturbance incorporation in upland areas. All efficiency values are available in Table 2 (Nutrient loss reduction efficiency values for upland regions of the Chesapeake Bay Watershed).
Phase 6: The Expert Panel proposed that the CBP existing definitions and credits associated with implementation of Nutrient Management Plans (NMPs) be replaced by independent sets of practice elements for nitrogen and phosphorus management due to the marked difference in the use, fate, and transport of these nutrients in agricultural systems. The structures for both N and P nutrient management are similar, however, with supplemental management elements stacked onto a required core set of management elements.
Phase 5.3.2 (Recommendations linked here): The Panel proposed that the existing set of Nutrient Management practices (nutrient management, enhanced nutrient application, and decision/precision agriculture) be replaced by three tiers of management: (1) Crop Group Nutrient Application Management (CGNAM), (2) Field Level Nutrient Application Management (FLNAM), and (3) Adaptive Nutrient Management (ANM). These practices are defined in the body of the report.
Nontidal Wetland Creation, Rehabilitation and Enhancement
Formed to build upon the CBP-approved report by a previous Wetland Expert Panel that clarified the wetland restoration BMP and established two nontidal wetland land uses in the Phase 6 Chesapeake Bay Watershed Model, the Wetland Workgroup formed an Expert Panel to evaluate the effectiveness of nontidal wetland best management practices (BMPs) to reduce N, P, S loads to the Bay. The panel recommended updated pollutant removal efficiencies for wetland creation and enhancement, summarized in the report, and Wetland enhancement was not recommended for credit by the Expert Panel. This panel did not change the existing definition or effectiveness estimates for wetland restoration.
Riparian Forests & Grass Buffers
The Riparian Buffer Expert Panel reviewed data on nutrient and sediment reductions from riparian buffers to determine whether updates or enhancements to riparian buffer practices were necessary. The review conducted by this Expert Panel builds off of the previous assessment of the riparian forest and grass buffers completed in 2009 by Simpson and Weammert. The Riparian Buffer Expert Panel concluded that there is insufficient new information on buffer efficiencies to make comprehensive changes to the set of efficiencies for buffers. The Panel recommends one adjustment to the existing credits for forest riparian buffers for the next model iteration. This adjustment is for an additional 0.014 lb/foot of total nitrogen reduction for instream processing efficiency when riparian forest buffers that are established on both sides of the stream.
Note: In 2021, the Forestry Workgroup recommended that the CBP approve a 15 year credit duration for all tree planting practices. View the updated credit duration recommendations here.
Additional Expert Panels Undertaken by the AgWG