Published on October 4, 2007
BMP Project Statusand Overview: BMP Project Status and Overview Tom Simpson Sarah Weammert University of Maryland Mid Atlantic Water Program [email protected] 301-405-1215 Agricultural Nutrient and Sediment Reduction Workgroup July 12, 2007 Presentation Outline: Presentation Outline Process Overview Explanation of Approach Recommended efficiencies Next Steps Discussion Process: Process Scientific Literature Search Development of Practice Definition and Efficiency Review Documentation and Reporting Year One BMPs: Year One BMPs Field and Pasture Erosion Control Practices Conservation Tillage Off-stream Watering Practices Buffers Cover Crops Forest Harvesting Practices Wetland Restoration and Creation Urban wet ponds and wetlands Urban erosion and sediment control Dry detention ponds and hydrodynamic structures Dry extended detention basins Urban stream restoration Desired outcome of BMP review and revisions: Desired outcome of BMP review and revisions Develop BMP definition and efficiency that reflects what field implementation Revise efficiency, as needed, to be as close as possible to what occurs under average implementation and O&M with widespread adoption, accounting for variability across space and time Generate efficiencies that can be used in CBP WSM Ph5 for calibration and to estimate both progress and scenario reductions as close as possible to what will occur WSM BMP efficiencies: WSM BMP efficiencies Realistic estimates of actual performance Not designed to be: Aspirational Promotional Maintenance of status quo (unchangeable) Designed to be applied in an adaptive management framework Uses of BMP efficiencies: Uses of BMP efficiencies Tributary Strategies Trading TMDLs MS4 Permits? Conservation Effect Assessment Project Used by states and feds across country Slide9: “Adaptive management does not postpone actions until ‘enough’ is known about a managed ecosystem (Lee, 1999), but rather is designed to support action in the face of the limitations of scientific knowledge and the complexities and stochastic behavior of large ecosystems (Holling, 1978). Adaptive management aims to enhance scientific knowledge and thereby reduce uncertainties. Such uncertainties may stem from natural variability and stochastic behavior of ecosystems and the interpretation of incomplete data (Parma et al., 1998; Regan et al., 2002), as well as social and economic changes and events (e.g., demographic shifts, changes in prices and consumer demands) that affect natural resources systems. National Academy of Sciences, National Research Council, 2004 Cover CropsMeeting – July 6, 2007: Cover Crops Meeting – July 6, 2007 Josh McGrath, UMD Dean Hively, USDA-ARS Dave Hansen, UDEL Ken Staver, UMD-Wye Research Center Russ Brinsfield, UMD-Wye Research Center Andy Clark, USDA-SAN Bob Kratochvil, UMD Jack Meisinger, USDA-ARS Russ Perkinson, VDCR Mark Dubin, UMD-CBPO Kelly Shenk, US-EPA-CBPO Slide11: For conventional plow till subtract 5% for all to account for mineralization of N due to tillage For fly-on seeding use 50% of all values From cc rye to wheat multiply by .8 From cc wheat to commodity wheat/barley multiply by .5 From early to standard multiply by 0.5 These are research level efficiencies, adjust by 0.75 for spatial, temporal and O&M variability Research-scale cover crop N uptake efficiency Slide12: For conventional plow till subtract 5% for all to account for mineralization of N due to tillage For fly-on seeding use 50% of all values From cc rye to wheat multiply by .8 From cc wheat to commodity wheat/barley multiply by .5 From early to standard multiply by 0.5 Recommended cover crop nitrogen uptake efficiencies (Conservation tillage) Phosphorus and Sediment: Phosphorus and Sediment Reviewed and supported the current efficiencies for phosphorus and sediment, as revised and adopted in 2003 Buffers: Buffers Developer- Carrie Graff; Reviewer – Richard Lowrance and Judy Okay UMD contracted with Graff, Limnotech Inc., to run the Riparian Ecosystem Management Model for grass and forested buffers. Delays in and questions about model input data and questions about input hydrology (flux) have raised questions about Met with experts in mid-June to discuss Meetings/discussions: Meetings/discussions Richard Lowrance, ARS-Tifton, Andrew Sharpley, U. Ark., Judy Meyer, UGA Deanna Osmond, NC State Greg McCarty, Dean Hively and other, ARS-Beltsville Lowrance, Sharpley and Meyer: Lowrance, Sharpley and Meyer Agreed that N should be 30-40% and P 20-30%, vary by geomorphic regions but Lowrance changed mid upon return home and suggested values similar to current Sharpley had no comment on N but questioned DRP removal by buffers Simpson raised question of P accumulation in buffer making it a source of P in future based on P site index work Osmond, NC: Osmond, NC NC had set buffer N efficiencies of 75-85% based on limited research data In 1996, established buffer research watershed and monitored at different times throughout last 10 years Data support 30% N reduction but have revised state efficiencies to 20-60% based on buffer width to promote wider buffers and to “soften” change Their data suggest buffers are a source of P over time, not a sink, so do not give buffers a P efficiency Hively and others at Beltsville: Hively and others at Beltsville Monitored “OPE-3” watershed field and buffer for ~8 years Found nonuniform gw and sw flow through field and buffer Upwelling in buffer represented major discharge areas One site was 0.06% of total riparian area but contributed 10-15% of flow and 30-40% of NO3 REMM-Grass Riparian Buffers: REMM-Grass Riparian Buffers REMM was run for grass buffers in representative settings in two hydrogeomorphic regions: the Great Valley (Shenandoah) and the Eastern Shore (Talbot County, MD). Time and funding precluded more runs. Propose to extrapolate for other regions. . Location %N reduction %P reduction Shenandoah high till 46.7 32.9 Shenandoah low till 80.3 43.2 Talbot high till 71.5 29.3 Talbot low till 54.9 35.0 Riparian Forest Buffers: Riparian Forest Buffers REMM was run for same areas with same assumptions as for grass. For the Shenandoah, only results from buffers treating high till cropland have not been received. The results for the forested buffers are shown below. Location %N reduction %P reduction Shenandoah high till 78.7 27.3 Shenandoah low till Talbot high till 82.1 29.1 Talbot low till 91.2 36.9 BMP Project Recommendation(Goes to FWG on Monday): BMP Project Recommendation (Goes to FWG on Monday) Adapt current hydrogeomorphic region buffer N efficiencies to account for scaling up, spatial and temporal variability and non-uniform flow Quantitative data is limited but based on NC and Beltsville may be >50% Given limited data, recommend adjusting current efficiencies by 20-33% as interim measure Keep grass as 70% of forest for N Make P efficiencies same for grass and forest and a range of 25-40% across regions Field and Pasture Erosion Control Practices: Field and Pasture Erosion Control Practices Developer/Expert - Tom Simpson & friends Reviewer - Russ Perkinson Name change – formerly Farm Conservation Plans. Description/Definition lists typical practices that may be utilized to reach soil loss tolerance. Field and Pasture Erosion Control Practices: Field and Pasture Erosion Control Practices No change to efficiencies - supported by reviewer and AgNRWG Field and Pasture Erosion Control Practices: Field and Pasture Erosion Control Practices Issues Jurisdictions represented at the May 10, 2007 AgNRWG meeting requested the name and description change. MD is not supportive of the description and name change and wants more time for internal review. NRCS supportive of description and name change. Status pending on MD review Conservation Tillage: Conservation Tillage Advisor – Jack Meisinger; Reviewer – Josh McGrath Mark Dubin added NRCS practice codes definition Efficiencies supported by UMD, reviewers and AgNRWG Conservation Tillage: Conservation Tillage No opposition expressed to efficiencies but AgNRWG is discussing how reporting issues will determine which approach to use. Multiple issues: How practice is defined Residue cover versus SCI and STIR values – Mark Dubin is working w/ NRCS to address this Reporting Can we separate conservation tillage and no-till Different efficiencies???? Separating Conservation Tillage and No-till?: Separating Conservation Tillage and No-till? If done, MAWQ project staff recommend that each conservation tillage technique be assigned its own reduction for TP and TS, but no difference between TN because there is no agreement on what the value should be: 20% on conservation tillage; 40% on no-till As with single practice, TN load reduction approach would depend on the ability to separate surface and subsurface flow. Off-Stream Watering Practices: Off-Stream Watering Practices Developer – Theo Dillaha; Reviewer – Mary Leigh Wolfe Three practices to review Off-stream watering with fencing Off-stream watering without fencing Off-stream watering with rotational grazing Off-stream watering with fencing: Off-stream watering with fencing Off-stream watering with fencing: Off-stream watering with fencing Issues: Should a minimum fencing distance be established in the definition? Setbacks vary by state NRCS codes as some states specify a distance and in some it is a judgment call (MD). AgNRWG requested more time to review Off-stream watering without fencing: Off-stream watering without fencing Recommend adding shade as part of this BMP. Issues with tracking? Off-stream watering without fencing: Off-stream watering without fencing Dillaha recommended a 50% reduction in reported efficiencies to be conservative based on limited data. MAWP does not support. AgNRWG agreed reported values were low, did not support Dillaha’s recommended adjustment and requested more time to review UMD’s recommendation. Off-stream watering w/ rotational grazing: Off-stream watering w/ rotational grazing MAWP recommends that further review of rotational grazing be delayed until the Year 2 due based on following considerations: Treat as stand alone BMP (not compared or grouped with pasture and stream protection). Propose to add to other grazing management practices in Year 2. Work on all pasture management practices to assure consistent definitions and efficiencies. CBP partners, including NY, PA, and USDA-NRCS requested that definition/efficiency be developed later considering additional research sources. Conclusions so far: Conclusions so far Have much better understanding of BMPs, definitions and efficiencies Review was needed for a long time Proposed definitions and efficiencies are more accurate, realistic and defensible than current ones Many BMP specific experts involved Adjustments may cause some reduction in modeled BMP implementation progress This is a successful adaptive management approach and the world is again watching us and following our lead Questions?Discussion?: Questions? Discussion?