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Buffalo River and Long Branch Sediment TMDLs. Upper Buffalo River. Middle Buffalo River. Public Meeting Gene Yagow April 25, 2013. Long Branch. Lower Buffalo River. Overview. Impairment Stressor Analysis → Sediment Watershed characterization GWLF sediment modeling

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Buffalo river and long branch sediment tmdls

Buffalo River and Long Branch Sediment TMDLs

Upper

Buffalo

River

Middle

Buffalo

River

Public Meeting

Gene Yagow

April 25, 2013

Long Branch

Lower

Buffalo

River


Overview
Overview

  • Impairment

  • Stressor Analysis → Sediment

  • Watershed characterization

  • GWLF sediment modeling

  • Reference Watershed Approach

  • TMDL components

  • Allocation Scenarios



Biological monitoring and rating
Biological Monitoring and Rating

Healthy

Impaired

VSCI = Virginia Stream Condition Index


Biological monitoring and rating1
Biological Monitoring and Rating

Healthy

Impaired

VSCI = Virginia Stream Condition Index



Stressor analysis sediment
Stressor Analysis → Sediment

  • Long Branch

    • Poor habitat metric scores for: “Sediment Deposition”

    • > 50% mean Embeddedness

    • LRBS = 0.28 (LRBS > -0.5 indicates normal sediment load)

  • Buffalo River

    • Poor habitat metric scores for: “Riparian Buffer Zone Width”

    • > 50% mean Embeddedness

    • LRBS = - 0.32



Watershed characterization1
Watershed characterization

Watershed segmentation

Land use

Soils

Slope

“Future Growth”

Existing BMPs




Future growth
Future Growth

  • Simulation of a “future” land use condition

    • Assume growth is minimal in the watershed

    • Allocated construction permit area as 2% of developed land uses


Bmp representation
BMP representation

  • DCR data downloaded by 6th order watershed for those BMPs relevant to sediment removal

  • None in the reference watershed, but several throughout the Long Branch and Buffalo River watersheds

  • BMPs are land use-specific

  • BMPs were credited as:

    • A land use change, or as

    • An efficiency applied to the applicable land use or to the upland area benefitted



Example reference watershed tmdl

TMDL Target Load

Reducing load in the impaired watershed to the target TMDL load is expected to restore the benthic community

Example Reference Watershed TMDL

Impaired

Load

Non-impaired

ImpairedWatershed

TMDL Reference Watershed


Impaired and comparison watersheds
Impaired and Comparison Watersheds

Healthy VSCI Score

Land use distribution

Size

Slope

Elevation

Physiographic region

River basin

Soil erodibility

Beaver

Creek

Harris

Creek

Reed

Creek

Wreck

Island

Creek

Fishpond

Creek

SF Falling

River


Reference watershed selection
Reference Watershed Selection

  • Fishpond Creek

    • Most similar land use distribution

    • Smallest drainage area


Reference watershed selection1
Reference Watershed Selection

  • Fishpond Creek

    • Most similar land use distribution

    • Similar elevation


Reference watershed area adjustment example

HYSadj

4,252 ha

Reference Watershed Area-adjustment Example

HYS

20,789 ha

TMB

4,252 ha



Gwlf sediment loads
GWLF Sediment Loads

Cropland

Pasture

Categories

Developed

Land uses

LDI = low intensity developed; MDI = medium intensity developed; HDI = high intensity developed

TMDL


Gwlf sediment loads1
GWLF Sediment Loads

Cropland

Pasture

Categories

Developed

Land uses

LDI = low intensity developed; MDI = medium intensity developed; HDI = high intensity developed

TMDL



Permitted sediment loads wla
Permitted Sediment Loads (WLA)

Industrial Stormwater General Permits

*Average annual runoff simulated for the HDI land use category.

Construction Permits

*Average annual load simulated for the Barren land use category.


Long branch sediment tmdl components
Long Branch Sediment TMDL Components

  • TMDL = WLA + LA + MOS

    • TMDL = area-adjusted load from reference watershed

    • WLA = permitted loads

    • MOS = margin of safety (10%)

    • LA = remaining load allocated for non-point sources


Buffalo river sediment tmdl components
Buffalo River Sediment TMDL Components

  • TMDL = WLA + LA + MOS

    • TMDL = area-adjusted load from reference watershed

    • WLA = permitted loads

    • MOS = margin of safety (10%)

    • LA = remaining load allocated for non-point sources



Allocation scenarios long branch
Allocation Scenarios – Long Branch Components

  • Sediment load reductions are required

    • from “Future” Conditions in Long Branch

    • To the target allocation load

Target Allocation Load = TMDL - MOS

= 456.5 – 45.6 = 410.9 tons/yr


Allocation scenarios buffalo river
Allocation Scenarios – Buffalo River Components

  • Sediment load reductions are required

    • from “Future” Conditions in Buffalo River

    • To the target allocation load

Target Allocation Load = TMDL - MOS

= 4,414.8 – 441.5 = 3,973.3 tons/yr


Potential sediment reduction targets
Potential Sediment Reduction Targets Components

Pastures with stream access

Pastures with fair or poor conditions

Eroding field roads

Localized disturbed areas


Next steps
Next Steps Components

  • Report will be available April 30, 2013

  • Public comment open until June 13, 2013

  • Finalize report and submit to EPA

  • Begin implementation planning


Contact information
Contact ComponentsInformation

Gene Yagow Biological Systems Engr. Dept.

306 Seitz Hall (0303)Virginia TechBlacksburg, VA 24061

[email protected]


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