OVERVIEW OF SUSPENDED SOLIDS TRANSPORT AND LIVING RESOURCE INTERACTIONS

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OVERVIEW OFSUSPENDED SOLIDS TRANSPORT AND LIVING
RESOURCE INTERACTIONS

• Ross Mandel
• Interstate Commission on the Potomac River Basin
• March 8, 2004

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SSTLR

• U. S. Army Corps of Engineers, Baltimore District
• Metropolitan Council of Governments
• Carl Cerco
• Engineering Research Development Center
• Supported by
• D. C. Department of Health
• Maryland Department of the Environment
• Chesapeake Bay Program

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GOALS OF SSTLR

• Improve Representation of Suspended Sediment
• Better Simulation of Relation Between Suspended
  Sediment and Living Resources (Algae, SAV)
• Specific Improvements to Eutrophication Model in
  the Potomac

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JANUARY 6, 2004 CBP MODELING SUBCOMMITTEE MEETING

• http//www.chesapeakebay.net/calendar.cfm

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TOPICS

• Refined Modeling Grid
• Bank Loads
• Resuspension and Settling of Sediments
• Light Attenuation
• Phosphorus Dynamics
• pHAlkalinitySediment P Release
• Algal Speciation

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REFINED MODELING GRID

• Improve representation of shoreline processes
• Represent DC, MD, and VA waterbodies on
  303(d)Lists (including Anacostia River)
• Sung-Chan Kim (ERDC)
• Sung-Chan.Kim_at_erdc.usace.army.mil

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BANK LOADS
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BANK LOADS--CURRENT MODEL
Cerco and Noel (2003) http//www.chesapeakebay.ne
t/modsc.htm
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BANK LOADS--SSTLR

• Simulate bank erosion by wave action
• New bank erosion surveys in MD, VA

Photo borrowed from Halka and Hennessee (MSC
1/6/04)
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SEDIMENT RESUSPENSIONCURRENT MODEL

• Resuspension not represented as a physical
  process
• Net Settling Settling Resuspension
• Net Settling Rates 5-10 of Actual Settling
  Velocity

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RESUSPENSION RESEARCHSSTLRFOUR AXIAL SURVEYS OF
POTOMAC

• Larry Sanford (UMCES)
• Carl Friedrichs (VIMS)
• Jerome Maa (VIMS)
• Joe Gailani (ERCD)

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SURVEY SITESfrom Sandford et al. MSC 1/6/04
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PARTICLE SETTLINGSSTLRPHYTOPLANKTON-SEDIMENT
INTERACTIONSMichael Kemp and Walter Boynton
(UMCES)
Diatom-Clay Aggregate Hamm (2002) via Kemp and
Boynton MSC 1/6/04
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LIGHT ATTENTUATIONCURRENT MODEL
a1 to a5 empirical constants ISS inorganic
suspended solids concentration (g m-3) VSS
organic suspended solids concentration (g
m-3) DOC dissolved organic carbon (g C m-3) Chl
chlorophyll (mg m-3)
Cerco and Noel (2003)
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LIGHT ATTENTUATIONSSTLRCharles Gallegos
(Smithsonian)

• Reformulate Representation of Light Extinction in
  terms of Inherent Optical Properties (Absorption
  and Scattering)
• Field measurements of spectral backscattering,
  total scattering, and absorption
• Laboratory measurements of absorption components

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PHOSPHORUS CYCLECURRENT MODEL
Cerco,MSC 1/6/04
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PHOSPHORUS CYCLESSTLRJeff Cornwell (UMCES) and
Vic Bierman (Limno-Tech)
Cornwell, MSC 1/6/04
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PHOSPHORUS CYCLESSTLR

• Add Particulate Inorganic Phosphorus to Model
• Determine Bio-availability of P Species
• Field Work in Potomac Characterize
  Spatial/Temporal Distribution of P Species
• Laboratory Work Determine P Sorption

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pH-ALKALINITY-PHOSPHORUS DYNAMICS

• James Fitzpatrick (Hydroqual)
• Vic Bierman and Joe DePinto (Lino-Tech)

Smith Point, September 2003 Bierman, MSC 1/6/04
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1983 ALGAL BLOOM

• 1970s Phosphorus Controls Installed at Blue
  Plains and Elsewhere to Control Algal Blooms
• 1983 High Spring Flows, Low Summer Flows, Below
  Normal Wind Speeds, Higher Temperatures
• July November Microcycstis Bloom From
  Piscataway Creek to Indian Head, Maximum
  Concentrations gt 200ug/L
• pH Rises from 7 to 9-10 in Vicinity of Bloom

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MECHANISMModeled in Revised Potomac
Eutrophication Model (PEM) Post-1983

• Uptake of Inorganic Carbon By Algae Raises pH
• High pH ( 9-10) Causes Dramatic Increase in P
  Released From Sediments
• Increased P Concentration Increases Algal Growth

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PHOSPHORUS SORPTION DYNAMICS
Hydroqual, (MWCOG 1989)
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pHP SORPTION RELATION
Hydroqual, (MWCOG 1989)
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pH-ALKALINITY MODEL--SSTLR

• Put pH P Release Dynamics from PEM in Current
  Sediment Nutrient Flux Model
• New State Variables and Dynamics to Represent pH,
  Alkalinity, and Calcium in Water Column

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ALGAL SPECIATIONVic Bierman (Limno-Tech) and
Chris Jones (GMU)

• Improve representation of sources, succession,
  food-web dynamics
• Improve representation of spring diatom bloom
• Improve representation of Microcystis dynamics

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ICPRB SUPPORTED ACTIVITIESFUNDED BY EPA REGION
III 104(B) GRANT

• Field Characterization of Sediment P and
  Laboratory Analysis of pH-Mediated Sediment P
  Release ( Boynton and Cornwell, UMCES)
• Collection and Analysis of pH-Alkalinity Data for
  Potomac Estuary
• Review Connection Between Algal Speciation,
  Chlorophyll Criteria, and Higher Trophic Levels

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SCHEDULE

• COMPLETION DATE
• 2007

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CONTACT INFO

• Ross Mandel
• Interstate Commission on the Potomac River Basin
• rmandel_at_icprb.org