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Developing Linkage Between Sediment and Aquatic Life

Developing Linkage Between Sediment and Aquatic Life. Gene Yagow Virginia Tech Biological Systems Engineering Department December 5, 2012 A Webinar Presentation to the Joint DEQ-DCR TMDL Work Group. Overview. Intro to Maryland’s Methodology Out-of-Bay application example

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Developing Linkage Between Sediment and Aquatic Life

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  1. Developing Linkage Between Sediment and Aquatic Life Gene Yagow Virginia Tech Biological Systems Engineering Department December 5, 2012 A Webinar Presentation to the Joint DEQ-DCR TMDL Work Group

  2. Overview • Intro to Maryland’s Methodology • Out-of-Bay application example • Little Otter River and Buffalo Creek • GWLF • Potential In-Bay application example • Taylor Creek, CBWM • Long Meadow Run and Turley Creek, pseudo-GWLF

  3. Maryland’s Methodology Summary • Non-tidal sediment impairments • at the 8-digit watershed level • 24 watersheds: 12 impaired, 12 reference • Long-term average annual sediment loads • CBWM EOS target loading rates by 13 landuses • Spatially-explicit, landuse-specific SDRs • Load calculations • existing (2006) • all-forested

  4. Maryland’s Methodology (cont.) • Developed relationships between sediment and aquatic life • Sediment: normalized forest load (existing load/all-forest load) • Aquatic Life: benthic IBI • Two methods • EPA method: 75th %-ile of reference watershed values • Logistical regression with an 80% confidence interval • 2006, revised and updated in 2009 • Validated with habitat sediment metrics

  5. Maryland’s Target Sediment Threshold Sediment / Aquatic Life Relationship Methods Comparison Reference Impaired Maryland’s sediment threshold Habitat Sediment Metrics Validation

  6. Little Otter River/Buffalo Creek Application Example

  7. SelectedWatersheds N.F. Buffalo River (BNF) Northern Piedmont Buffalo Creek (BLD) Hat Creek (HAT) Blue Ridge Ridge and Valley Buffalo Creek (BWA) Little Otter River (LOR) Impaired Green Creek (GCR) Piedmont Big Chestnut Creek (CNT)

  8. GWLF Sediment Modeling UAL = Load / Area Adjusted UALref = UALref x SDRimp / SDRref

  9. Reference Watershed Approach CNT TMDL = AreaIMP x UALREF Target Load = TMDL - MOS RWA:

  10. All-Forest Load Multiplier Approach AllForX = Existing Load / All-Forest Load TMDL = AllForX x AllForLoadIMP Target Load = TMDL - MOS • MOS Options: • implicit • Default explicit value, e.g., 10% • (AllForX60 – AllForXLCL)/AllForX60 80% CI Upper CL: 3.24 Lower CL: 2.65 2.65 2.94 RWA: AllForX:

  11. Validation of AllForX with Habitat Sediment Metrics

  12. Taylor Creek Application Example

  13. SelectedWatersheds Blue Ridge Ridge and Valley Northern Piedmont I I I Piedmont I

  14. CBWM Sediment Modeling

  15. All-Forest Load Multiplier Approach Taylor Creek 2.93 1.46 3.152

  16. Target Load ComparisonTaylor Creek (TLR) tons/yr tons/yr tons/yr DM: tons/yr AllForX: tons/yr AllForX - select: Target Load = TMDL - MOS

  17. Validation of AllForX with Habitat Sediment Metrics

  18. Turley Creek and Long Meadow RunGWLF Application Example(uses DCR 2006 VAHU6 modeling and a nearby watershed group)

  19. Selection Criteria • DEQ biological monitoring • 9 or more samples • Nearby in same basin • 1st – 3rd order streams • Must include some non-impaired streams Turley Creek Long Meadow Run

  20. GWLF Sediment Modeling (≈DCR,2006) AllForX = Existing Load / All-Forest Load

  21. All-Forest Load Multiplier ApproachTurley Creek and Long Meadow Run LOM LOM TRL TRL 3.07 2.21 DM: AllForX: AllForX (LOM): AllForX (TRL):

  22. AllForX Procedure Summary • Identify 3-6 nearby DEQ bio-monitoring stations that are non-impaired • 9+ samples each • Same river basin as impaired stream • 1st to 3rd order streams • Simulate existing and all-forest loads, then AllForX • Calculate average VSCI and habitat sediment metric scores from EDAS • Develop regression between VSCI and AllForX • Exclude non-impaired stations with AllForX > the impaired station • Calculate 80% confidence intervals • Set target load = All-Forest load x AllForXLCL • Calculate MOS = (AllForX60 – AllForXLCL)/AllForX60

  23. Issues and Unanswered Questions • Period for summary of biological data? • Marginally-impaired and urban streams? • Fourth quadrant problems? • DEQ biologists screening procedure for sediment-dominated impairments?

  24. Questions • Presentation available at: ftp://bsesrv214.bse.vt.edu/Yagow/LittleOtter_BuffaloCrk/ • File name is: “AllForestedReferenceApproach_120512.pptx”

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