Sediment Quality Assessment and Management Framework for Dam Removal Projects Brian Graber & Karen Pelto Riverways Program, Massachusetts Fish & Game Joseph.

Sediment Quality Assessment Sediment Quality Assessment and Management Framework and Management Framework

for Dam Removal Projectsfor Dam Removal ProjectsBrian Graber & Karen Pelto Brian Graber & Karen Pelto Riverways Program, Massachusetts Fish & GameRiverways Program, Massachusetts Fish & Game

Joseph Rathbun Joseph Rathbun Water Bureau, Michigan Dept. of Environmental QualityWater Bureau, Michigan Dept. of Environmental Quality

James TurekJames TurekNOAA Restoration CenterNOAA Restoration Center

Laura WildmanLaura WildmanAmerican RiversAmerican Rivers

Basic Concepts: Basic Concepts: Reservoirs are Sediment TrapsReservoirs are Sediment Traps

Many trap Many trap 95 %95 % of the sediment that enters of the sediment that enters them from upstreamthem from upstream

LargeLarge sediment particles typically form sediment particles typically form deltas at upstream enddeltas at upstream end

SmallSmall sediment particles typically sediment particles typically transported farther into reservoirtransported farther into reservoir– Many contaminants typically bind to small particlesMany contaminants typically bind to small particles

Basic Concepts: Issues with Basic Concepts: Issues with Contaminated SedimentContaminated Sediment

Direct Direct toxicitytoxicity to organisms to organisms– AcuteAcute– ChronicChronic

BioaccumulationBioaccumulation in organisms in organisms

Alter Alter benthic communitybenthic community

Contaminate overlying Contaminate overlying waterwater

Affect disposal of Affect disposal of dredged materialdredged material

Sediment Assessment Framework

Reconnaissance and/or definitive survey

SQC exceeded

Analyze transport capacity & downstream sensitivity

Low transport capacity

High transport capacity

Not bioavailable Bioavailable

Initial screening indicates sediment contamination likely

SQC not exceeded

(Optional)

Sediment ManagementFramework

Initial Landscape-Level Initial Landscape-Level ScreeningScreening

Screen impoundment Screen impoundment sediment quality based sediment quality based on on landscape-level GISlandscape-level GIS informationinformation

Screening can flag an Screening can flag an impoundment, impoundment, watershed, or regionwatershed, or region for for likely contaminantslikely contaminants

Predictive Model - RISQAPredictive Model - RISQA

RRegionalegional

IImpoundedmpounded

SSediment ediment

QQualityuality

AAssessmentssessment

Working with USGSWorking with USGS

Probabilistic model to Probabilistic model to estimate:estimate:

– Sediment quantitySediment quantity– Trace elementsTrace elements– Organic contaminantsOrganic contaminants

Developing and Validating RISQADeveloping and Validating RISQA

Compile existing data on sediment quality Compile existing data on sediment quality and quantity in impoundmentsand quantity in impoundments

Field assess volume and quality of sediment Field assess volume and quality of sediment in selected impoundmentsin selected impoundments

Develop and validate a GIS-based model for Develop and validate a GIS-based model for predicting sediment quantity and quality predicting sediment quantity and quality based on basin characteristicsbased on basin characteristics

*preliminary data**preliminary data*

HazardHazard ImpoundmentImpoundment PEC PEC exceedancesexceedances

Sig.Sig. PXZ-001PXZ-001 nonenone

Sig.Sig. D2Z-008D2Z-008 PAHPAH

HighHigh UXZ-001UXZ-001 Cd, Cu, Pb, CrCd, Cu, Pb, Cr

Sig.Sig. NUZ-001NUZ-001 CuCu

LowLow HKZ-001HKZ-001 nonenone

nonenone LVZ-001LVZ-001 CrCr

LowLow A2Z-001A2Z-001 nonenone

LowLow PTZ-001PTZ-001 Pb, PAH, PCBPb, PAH, PCB

Sig.Sig. FTZ-001FTZ-001 Cd, PbCd, Pb

Sig.Sig. AJZ-001AJZ-001 DDEDDE

Combine Combine dam hazard classificationdam hazard classification with contaminant with contaminant assessment?assessment?

Preliminary Modeling ResultsPreliminary Modeling ResultsPreliminary Modeling ResultsPreliminary Modeling Results

Preliminary regression analyses indicate that Preliminary regression analyses indicate that sediment contamination variability may be sediment contamination variability may be best explained by:best explained by:

• Percent impervious areaPercent impervious area

• Number of point sources Number of point sources (NPDES, 21E, underground tanks, etc.)(NPDES, 21E, underground tanks, etc.)

Additional impoundments are currently Additional impoundments are currently being assessed to validate the modelbeing assessed to validate the model

Preferred Survey Design ProcessPreferred Survey Design Process

1.1. Establish Establish study objectivesstudy objectives, evaluate , evaluate existing data, etc.existing data, etc.

2.2. Conduct Conduct reconnaissancereconnaissance surveysurvey

3.3. Refine study objectivesRefine study objectives - Choose minimum number of stations that - Choose minimum number of stations that

are representative of study areaare representative of study area

4.4. Conduct Conduct definitive surveydefinitive survey

Reconnaissance SurveyReconnaissance Survey

ObjectivesObjectives– Sampling accessSampling access– Sample collectabilitySample collectability– Qualitatively assess nature and extent of depositsQualitatively assess nature and extent of deposits– Quantitatively collect a small number of (silt) Quantitatively collect a small number of (silt)

sediment quality samplessediment quality samples

EquipmentEquipment– Probing rod or tubeProbing rod or tube– Small grab or core samplerSmall grab or core sampler– GPSGPS

Reconn. Survey – Mud Music Reconn. Survey – Mud Music ♫♫

Use Use hollow metal tubehollow metal tube to identify surface to identify surface sediment type:sediment type:RockRock = bounce & clang = bounce & clangClayClay = bounce & silent = bounce & silentGravelGravel = crunch = crunchSiltSilt = silent, penetration = silent, penetrationSandSand = silent, no penetration = silent, no penetration

Reconn. sample from silt portionReconn. sample from silt portion

Moving from Reconn Survey to Moving from Reconn Survey to Definitive Survey Definitive Survey

Combine:Combine:Reconn survey infoReconn survey infoRegulatory guidelines/requirementsRegulatory guidelines/requirements– State specificState specific

Watershed screening information (due Watershed screening information (due diligence)diligence)Best professional judgmentBest professional judgment

To determine if additional assessment is To determine if additional assessment is neededneeded

ex. headwaters; run-of-river; gravelex. headwaters; run-of-river; gravel

Definitive SurveyDefinitive Survey

ObjectiveObjective

– Quantitatively Quantitatively establish magnitude establish magnitude and extent of contaminationand extent of contamination

EquipmentEquipment

– Grab or core samplersGrab or core samplers

– GPSGPS

Largely the same as reconn…Largely the same as reconn…

Definitive Survey Definitive Survey Sampling DesignSampling Design

How manyHow many samples will be collected samples will be collected

WhereWhere samples will be collected samples will be collected

HowHow samples will be collected samples will be collected

Sampling Design – How Many?Sampling Design – How Many?

Most subjective part of survey designMost subjective part of survey design

BBest est PProfessional rofessional JJudgment and regulatory udgment and regulatory guidelines guidelines – Minimum 50-ft diameter “hot spots”?Minimum 50-ft diameter “hot spots”?

$$$$$$$$ (affects sampling resolution) (affects sampling resolution)

Elipgrid-PCElipgrid-PC software software– Computes probability of locating “hot spots”Computes probability of locating “hot spots”– Based on total area, grid spacing, and potential Based on total area, grid spacing, and potential

hot spot size, shape, orientationhot spot size, shape, orientation– Can use to determine number of samplesCan use to determine number of samples

Sampling Design – Where?Sampling Design – Where?

Objective Objective of the studyof the study

Cost-effectivenessCost-effectiveness– Use Elipgrid-PCUse Elipgrid-PC

Sediment Sediment patternspatterns

Simple Random SamplingSimple Random Sampling

DamDam

Systematic Grid SamplingSystematic Grid Sampling

DamDam

Subjective SamplingSubjective Sampling

DamDam

OutfallOutfall

Stratified Random SamplingStratified Random Sampling

DamDamGravelGravel

BarBar

Silt BarSilt Bar

Sample Collection: Grab SamplingSample Collection: Grab Sampling

More “recent” sediments (?)More “recent” sediments (?)

Mixed, mobile surface layer Mixed, mobile surface layer – (grab 2 – 24 L)(grab 2 – 24 L)

““Biologically active” zoneBiologically active” zone– Upper 10 cm or soUpper 10 cm or so Ponar SamplerPonar Sampler

Sample Collection: Core SamplingSample Collection: Core Sampling

Recent to older sediment Recent to older sediment Stratified, less mobile depositsStratified, less mobile deposits– important if mobilized during removalimportant if mobilized during removal

Hand corersHand corers– Cores = a few feet long, 2” diameterCores = a few feet long, 2” diameter– Shallow waterShallow water

Gravity corers, piston corers, etc.Gravity corers, piston corers, etc.– Cores < 5’ longCores < 5’ long– Deep waterDeep water

VibrocorersVibrocorers– Cores = up to 20’ long, 4” diameterCores = up to 20’ long, 4” diameter– Deep water (> 1,000’)Deep water (> 1,000’)– Less disruption of sediment columnLess disruption of sediment column

Challenges in gravel, clayChallenges in gravel, clay

Sample Analysis - ChemicalSample Analysis - Chemical

Often only testing done – least Often only testing done – least expensiveexpensive

Methods well-establishedMethods well-established

Common analytes = Common analytes = metals, PCBs, PAHsmetals, PCBs, PAHs

Sediment Analysis – Sediment Analysis – ToxicityToxicity

Done less often than Done less often than chemical testingchemical testing– greater expensegreater expense– requires larger samplerequires larger sample

Why do toxicity testing?Why do toxicity testing?– Integrates effectsIntegrates effects– Uses important food chain Uses important food chain

organismsorganisms– Direct proof of effectsDirect proof of effectsNo effect = no pollution (?)No effect = no pollution (?)

Midge larvaeMidge larvae

AmphipodAmphipod

Data Interpretation:Data Interpretation:Sediment Quality CriteriaSediment Quality Criteria

Uses:Uses:

Evaluate sediment qualityEvaluate sediment quality

Establish cleanup objectivesEstablish cleanup objectives

Assess suitability for disposalAssess suitability for disposal

Assess suitability for Assess suitability for natural erosion & natural erosion & depositiondeposition

Agree to at start of projectAgree to at start of project

Chemical Concentration SQCChemical Concentration SQC

Tied to Tied to biological effectsbiological effects– Cu > X ppm = mortality in mayfliesCu > X ppm = mortality in mayflies

Usually tied to Usually tied to toxicitytoxicity rather than rather than bioaccumulation or changes in bioaccumulation or changes in community structure or human healthcommunity structure or human health

More often More often guidelinesguidelines than than regulationsregulations– vary state to statevary state to state

Database Chemical SQCDatabase Chemical SQC

PEC = probable effects concentration (above which effects are probable)PEC = probable effects concentration (above which effects are probable)

TEC = threshold effects concentration (below which effects rarely observed)TEC = threshold effects concentration (below which effects rarely observed)

Incr

easi

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Co

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ntr

atio

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crea

sin

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on

cen

trat

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PresumedPresumed

NontoxicNontoxic

PresumedPresumed

ToxicToxic

PossiblyPossibly

ToxicToxic

PECPEC

TECTEC

Sediment Management Framework

Fullsediment removal

Partialsediment removal

Cap or isolate

Natural erosion& deposition

Stageddam removal

Low transport capacity and/or

high d/s sensitivity

High transport capacity and/or

low d/s sensitivity

Not bioavailable Bioavailable

(Optional)

Complete Dam Removal & Complete Dam Removal & Natural Erosion & DepositionNatural Erosion & Deposition

Issue:Issue: demonstrate transport & deposition will demonstrate transport & deposition will not:not:

Cause Cause long-termlong-term adverse physical habitat adverse physical habitat changes downstream or upstreamchanges downstream or upstream– Fill pools, bury riffles, etc. downstreamFill pools, bury riffles, etc. downstream– Upstream channel incisionUpstream channel incision

Increase Increase bioavailabilitybioavailability (exposure/mobilization) of contaminants(exposure/mobilization) of contaminants

Staged Dam Removal & Staged Dam Removal & Natural Erosion & DepositionNatural Erosion & Deposition

Issues:Issues:

1.1. Assess Assess engineering suitabilityengineering suitability of dam of dam for staged removalfor staged removal

2.2. Assess probability, magnitude, Assess probability, magnitude, impacts of higher, “pulsed” impacts of higher, “pulsed” water water flows and sediment loadsflows and sediment loads on on downstream geomorphology and downstream geomorphology and ecologyecology

3.3. ((PlusPlus issues for complete dam issues for complete dam removal)removal)

On-Site Isolation or CappingOn-Site Isolation or Capping

Issue:Issue: demonstrate that: demonstrate that:

Capping will reduce contaminant Capping will reduce contaminant availability to aquatic and terrestrial availability to aquatic and terrestrial ecosystems, and humansecosystems, and humans

Capping won’t disrupt remaining Capping won’t disrupt remaining ecosystemecosystem– Decrease riparian zone, wetlands, Decrease riparian zone, wetlands,

bottomlands, etc.bottomlands, etc.

Partial Removal of Hot SpotsPartial Removal of Hot Spots

Tasks:Tasks:

1.1. Locate Locate hot spotshot spots

2.2. Remove & disposeRemove & dispose of sediment of sedimentIn the “dry” or “wet”In the “dry” or “wet”

3.3. Demonstrate that remaining sediment Demonstrate that remaining sediment is is nontoxicnontoxic

4.4. Post-remediation Post-remediation monitoringmonitoring

Sediment Removal – Sediment Removal – “Wet” & “Dry”“Wet” & “Dry”

(HRC, Inc.)(HRC, Inc.)

(ECT, Inc.)(ECT, Inc.)

Full Removal of All SedimentFull Removal of All Sediment

Tasks:Tasks:

1.1. Identify Identify extentextent of contaminated sediment, of contaminated sediment, inin 3D3D

2.2. Characterize Characterize degreedegree of contamination, for of contamination, for disposal decisionsdisposal decisions

3.3. Assess potential disturbance of original Assess potential disturbance of original channel bedchannel bed

4.4. Remove & disposeRemove & dispose5.5. Post-remediation Post-remediation monitoringmonitoring

Sediment Quality and Management Options

Reconnaissance and/or definitive survey

SQC exceeded

Analyze transport capacity & downstream sensitivity

Low transport capacity

High transport capacity

Not bioavailable Bioavailable

Initial screening indicates sediment contamination likely

SQC not exceeded

(Optional)

Sediment ManagementFramework

Contaminated Sediment = Contaminated Sediment = Run Away?Run Away?

Dams as a Dams as a long-termlong-term sediment and sediment and contaminant management plan?contaminant management plan?

Reservoir = contaminant Reservoir = contaminant “time bomb”“time bomb”

For more information:For more information:– Brian Graber, [email protected] Graber, [email protected]– Joseph Rathbun, [email protected] Rathbun, [email protected]