1Spray Drift ExposureSpray Drift ExposureRefinements forRefinements forSalmonidSalmonidOff-Channel HabitatChannel HabitatNick Poletika, DowNick Poletika, DowAgroSciencesAgroSciencesLLCRick Reiss, Exponent, Inc.Rick Reiss, Exponent, Inc.SteveCryer,DowAgroSciencesDowAgroSciencesLLCSteve Cramer, Cramer Fish SciencesSteve Cramer, Cramer Fish Sciences27 July 2010 EMPM Meeting27 July 2010 EMPM Meeting2BackgroundBackground3⁄4Pesticide exposure from spray drift deposition in PacificPesticide exposure from spray drift deposition in Pacificsalmonidsalmonidoff-channel habitat was identified as a specificchannel habitat was identified as a specificconcern in the 18 Nov 2008 National Marine Fisheriesconcern in the 18 Nov 2008 National Marine FisheriesService (NMFS) ESA Section 7 consultation biologicalService (NMFS) ESA Section 7 consultation biologicalopinionopinion3⁄4NMFS modeled offNMFS modeled off-channel exposure with thechannel exposure with theAgDRIFTAgDRIFT2.0.05 Aquatic Assessment Tool, static User2.0.05 Aquatic Assessment Tool, static User-defineddefinedWater Body with 10Water Body with 10-m width and 0.1m width and 0.1-m depthm depth3⁄4Two questions related to this exposure modelingTwo questions related to this exposure modelingemergedemergedzNature of offNature of off-channel habitat and related scenarios?channel habitat and related scenarios?zAppropriate transport and fate models?Appropriate transport and fate models?3Range of Off-Channel HabitatTypes3⁄4Examples given in NMFSExamples given in NMFSbiopzAlcoves, channel edge sloughs, overflowAlcoves, channel edge sloughs, overflowchannels, backwaters, terrace tributaries, offchannels, backwaters, terrace tributaries, off-channel dredge ponds, and braidschannel dredge ponds, and braids3⁄4For definition of exposure scenariosFor definition of exposure scenariosassociated with agricultural landscapes, isassociated with agricultural landscapes, isit necessary to include all examples?it necessary to include all examples?4Representative Data: Stream Segmentsin Oregon with Stream Survey Data andAgricultural UseSource: http://oregonstate.edu/dept/ODFW/freshwater/inventory/index.htm5Primary Channel, Secondary Channel,and Off-Channel Areas (m2)3⁄4Secondary (side) channels with flow can beconsidered “off-channel”3⁄4Note that secondary channel area >> other “offchannel” areaRiver Basin Primary Channel SecondaryChannelSecondaryChannel Area(%)Off ChannelOff-ChannelArea (%)Coquille 303,729 5,8081.881,3480.44Hood 424,232 14,8763.391,2930.29Rogue 675,047 29,8434.237290.10Umpqua 1,334,737 38,8772.838,9450.65Willamette 157,711 2,4041.504660.29Total 2,895,456 91,8083.0712,7690.436Off-Channel Habitat Data for SitesAdjacent to Agricultural Lands3⁄4Possible habitat units: alcove, backwater pool,isolated pool3⁄4Shade averages suggest presence of a riparianspray drift interception zone is commonLength (m)Width (m) Area (m2)Shade (%)HabitatUnitaNo. Mean Min Max Mean Min Max Mean Min MaxMeanMin MaxAlcove47 10.82 1.50 101.10 2.25 0.60 8.50 22.38 1.20 121.3070.995.60 100BackwaterPool147 10.06 1.00 85.20 2.95 0.50 13.00 36.11 0.90 545.3067.975.60 100IsolatedPool101 9.74 0.00 117.10 3.02 0.30 42.50 63.74 0.00 3621.0068.743.00 100All 295 10.08 0.00 85.20 2.860.30 42.50 43.29 0.00 545.3068.723.00 100aRiver basins: Coquille, Hood, Rogue, Umpqua, and Willamette. Note: not all units are present in all basins.7Salmonid Preference for Off-ChannelHabitat Found in Agricultural Areas3⁄4Stream-dwelling salmon and steelhead aredwelling salmon and steelhead arestrongly adapted to coldwater environmentsstrongly adapted to coldwater environments(<20°C) and to feeding on organisms that drift inC) and to feeding on organisms that drift inthe currentthe currentzMake use of side (secondary) channels for protectionMake use of side (secondary) channels for protectionfrom predatorsfrom predators3⁄4Will also use calm water habitats for refuge fromWill also use calm water habitats for refuge fromsuch factors as high velocity and highsuch factors as high velocity and hightemperaturetemperaturezAlcoves and backwaters preferredAlcoves and backwaters preferredzIsolated pools less favorable for migratory behaviorIsolated pools less favorable for migratory behaviorand may have reduced water qualityand may have reduced water quality8Off-Channel Features ofChannel Features ofImportance in Agricultural AreasImportance in Agricultural Areas3⁄4Three basic types, all with connection to theThree basic types, all with connection to themain channelmain channelzSide channelsSide channels•Flowing water bodies with clearly identifiable upstream andFlowing water bodies with clearly identifiable upstream anddownstream connectionsto the main channeldownstream connectionsto the main channelzAlcovesAlcoves•Water bodies that maintain a downstream connection to theWater bodies that maintain a downstream connection to themain channel at summer low flow, but have no upstreammain channel at summer low flow, but have no upstreamconnection during low flowconnection during low flowzBackwater poolsBackwater pools•A pool formed in freeA pool formed in free-flowing streams by an eddy alongflowing streams by an eddy alongchannel margins downstreamfrom obstructions such aschannel margins downstreamfrom obstructions such asbars,rootwadsrootwads, or boulders, or boulders9Source: http://www.fsl.orst.edu/pnwerc/wrb/Atlas_web_compressed/3.Water_Resources/3d.off-channel%20habs_web.pdfSide Channel



# W i l l

a me

t t e R i

v e r Ma

i

n C h

a n n e lExamples of Side Channels andExamples of Side Channels andAlcovesAlcovesAlcoveAlcoveSide Channel10HyporheicHyporheicFlow is Important inFlow is Important inAlcovesAlcovesSource: http://www.fsl.orst.edu/pnwerc/wrb/Atlas_web_compressed/3.Water_Resources/3d.off-channel%20habs_web.pdf11Example of Backwater PoolExample of Backwater PoolMokelumne River, CAPoolHwy 99 

# B a

r12Mass Exchange Occurs Between MainMass Exchange Occurs Between MainChannel and Backwater PoolsChannel and Backwater PoolsSource: CA Dep. Fish and Game. 1998. California Salmonid StreamHabitat Restoration Manual.Boulder FormedRoot Wad Formed13Exposure ProfileExposure Profile3⁄4Characteristics of the three types of offCharacteristics of the three types of off-channel habitatchannel habitatindicate flowing water is generally involvedindicate flowing water is generally involvedzSide channelSide channel–channelchannelflowzAlcovesAlcoves–hyporheichyporheicflow + mixing with main channelflow + mixing with main channelzBackwater poolsBackwater p–eddy current mass exchangeeddy current mass exchange3⁄4Time-weighted average (TWA) concentrations consistentweighted average (TWA) concentrations consistentwith exposure periods in acute toxicity tests (24with exposure periods in acute toxicity tests (24-96 hr)best describe exposure conditionsbest describe exposure conditions3⁄4Can normalize exposure periods usingCan normalize exposure periods usingGiesy’sreciprocity relationship (reciprocity relationship (Giesyet al., 1999)et al., 1999)3⁄4ToxicokineticToxicokineticmodeling approach also possiblemodeling approach also possible14Spray Drift Modeling ApproachSpray Drift Modeling Approach3⁄4Modeling methodology used to generate TWAModeling methodology used to generate TWAconcentration estimates for each type of offconcentration estimates for each type of off-channel habitatchannel habitatzSide ChannelsSide Channels•Stream Assessment Tool (SAT) inStream Assessment Tool (SAT) inAgDRIFTAgDRIFT2.0.05zAlcovesAlcoves•Predict initial deposition withPredict initial deposition withAgDRIFTAgDRIFT2.0.05 Aquatic2.0.05 AquaticAssessment Tool and use dye study measurements toAssessment Tool and use dye study measurements toestimate change in concentration over timeestimate change in concentration over timezBackwater PoolsBackwater Pools•Predict initial deposition withPredict initial deposition withAgDRIFTAgDRIFT2.0.05 Aquatic2.0.05 AquaticAssessment Tool and use channel flow data andAssessment Tool and use channel flow data andcomputational fluid dynamic modeling to estimate change incomputational fluid dynamic modeling to estimate change inconcentration over timeconcentration over time15Evaluation of Data Sources forEvaluation of Data Sources forCharacterizing OffCharacterizing Off-Channel HabitatChannel Habitat3⁄4CriteriaCriteriazRepresentative of agricultural areasRepresentative of agricultural areaszProvide reliable measurement data for modelProvide reliable measurement data for modelinputs•GeometryGeometry•FlowzSide channel currentSide channel currentzAlcove dye studyAlcove dye studyzMain channels (for fluid dynamic modeling of massMain channels (for fluid dynamic modeling of massexchange with backwater pools)exchange with backwater pools)16Representativeness for AgriculturalRepresentativeness for AgriculturalAreas-Method3⁄4Mapped offMapped off-channel habitat locations inchannel habitat locations inrelation to NLCD 2001 land cover classesrelation to NLCD 2001 land cover classesz11 Open Water11 Open Waterz81 Pasture/Hay81 Pasture/Hayz82 Cultivated Crops82 Cultivated Crops3⁄4Locations confirmed as representativeLocations confirmed as representativezWillamette River, OR.Willamette River, OR.BryentonBryenton(2007)zMokelumneMokelumneRiver, CA. JoeRiver, CA. JoeMerz, Cramer Fish, Cramer FishSciences, personal communicationSciences, personal communication17Willamette River AlcovesWillamette River Alcoves18MokelumneMokelumneRiver OffRiver Off-Channel PoolsChannel Poolsand Side Channelsand Side Channels19Side ChannelsSide Channels–EstimationEstimationMethodologyMethodology3⁄4SAT runs with numerical integration oftime/concentration curve at each distance inExport file20Inputs for SAT: Relationship of VelocityInputs for SAT: Relationship of Velocitywith Depth inwith Depth inMokelumneMokelumneRiver SideRiver SideChannels*Channels*Range of interest for modeling(p<0.01)* 133 measurements on two side channels, J.* 133 measurements on two side channels,J.Merz, personal communication21Inputs for SAT: Distribution of StreamInputs for SAT: Distribution of StreamVelocities inVelocities inMokelumneMokelumneRiver SideRiver SideChannelsChannels0204060801000 0.5 1 1.5 2 2.5PercentileMeanVelocity(ft/sec)= value used for modeling22Inputs for SAT: Distribution of Depth inInputs for SAT: Distribution of Depth inMokelumneMokelumneRiver Side ChannelsRiver Side Channels22= values used for modelingNMFSvalue23Inputs for SATInputs for SAT–Side ChannelsSide Channels3⁄4Velocity and dimensions characterized withVelocity and dimensions characterized withMokelumneMokelumneRiver dataRiver datazLower 10Lower 10thpercentile velocity: 0.07 ft/secpercentile velocity: 0.07 ft/seczDepths: 4 inches, 1 foot, and 2 feetDepths: 4 inches, 1 foot, and 2 feetzWidth: 10 meters, as per NMFS (insensitiveWidth: 10 meters, as per NMFS (insensitiveparameter)parameter)3⁄4Riparian interception factor: 0.2 (OR streamRiparian interception factor: 0.2 (OR streamsurvey shade data)survey shade data)24AlcovesAlcoves–Estimation MethodologyEstimation Methodology3⁄4Calculate initial concentration in alcoveCalculate initial concentration in alcoveusingAgDRIFTAgDRIFTAquatic Assessment ToolAquatic Assessment ToolzUser-defined water body determined bydefined water body determined bymeasured alcove dimensionsmeasured alcove dimensions3⁄4Estimate timeEstimate time-weighted concentrationweighted concentrationassuming an exponential decline curveassuming an exponential decline curvezModeled with residence time measurementModeled with residence time measurementtaken using trace dyestaken using trace dyes25Key Data for Alcoves in WillametteKey Data for Alcoves in WillametteRiverAlcoveWidth (feet)Width (feet)Depth(feet)ResidenceResidenceTime(hr)HarrisburgBar63.00.651GreenIsland75.42.05.5NorwoodSlough159.73.66026BackwatersBackwaters–EstimationEstimationMethodologyMethodology3⁄4Model flow in backwaters using 2Model flow in backwaters using 2-Dcomputational fluid dynamics (FLUENT 6.3.26)computational fluid dynamics (FLUENT 6.3.26)z2-D used because depth term contributes little toD used because depth term contributes little tomomentum equation relative to river widthmomentum equation relative to river widthzNormalized concentrationNormalized concentration-time relationship calculatedtime relationship calculatedfrom measured channel velocity and pool dimensionsfrom measured channel velocity and pool dimensions3⁄4Determine initial concentration in pool fromDetermine initial concentration in pool fromAgDRIFTAgDRIFTAquatic Assessment Tool with userAquatic Assessment Tool with user-defined water bodydefined water body3⁄4Apply concentrationApply concentration-time curve to initialtime curve to initialconcentration to calculate timeconcentration to calculate time-weightedweightedconcentration in poolconcentration in pool27BackwatersBackwaters–EstimationEstimationMethodologyMethodology3⁄4Modeling based on flow data from theModeling based on flow data from theMokelumneMokelumneRiver (River (PasternackPasternacket al., 2003)et al., 2003)zMeasurements made during a low dischargeMeasurements made during a low discharge“representative of salmon spawningrepresentative of salmon spawningconditionsconditions”zVelocity measurements in main river rangedVelocity measurements in main river rangedup to 4.6 ft/sec with a median ofup to 4.6 ft/sec with a median ofapproximately 1.6 ft/secapproximately 1.6 ft/seczRuns were made at 0.8 and 1.6 ft/sec velocityRuns were made at 0.8 and 1.6 ft/sec velocityin main stem of riverin main stem of river28Characteristics of Backwaters*Characteristics of Backwaters*Backwater PoolBackwater PoolWidth (feet)Width (feet)Depth (feet)Depth (feet)AIB1201.1Highway 99751.0AMBW #1300.8AMBW #2450.8* Pasternak et al., 2003.* Pasternak et al., 2003.29CFD Flow Predictions for HighwayCFD Flow Predictions for Highway99 Site99 Sitem s-130General InputsGeneral Inputs3⁄4Application rate of 1 lbApplication rate of 1 lba.i./A3⁄4Droplet sizesDroplet sizeszAerial•NMFS: FineNMFS: Fine-to-medium•Registrants: mediumRegistrants: medium-to-coarse per existing labelscoarse per existing labelsor agreements to change existing label languageor agreements to change existing label languagezGround:Ground:•Both NMFS and registrants used very fineBoth NMFS and registrants used very fine-fine3⁄4Ground deposition curveGround deposition curvezNMFS: 50NMFS: 50thpercentilepercentilezRegistrants: 90Registrants: 90thpercentilepercentile3031Worst-Case Estimates for EachCase Estimates for EachHabitatHabitatHabitatHabitatScenarioScenarioSide channel4 inch depth, 0.07 ft/secvelocityAlcoveNorwood slough, 60 hourresidence time, 3.6 ft depthBackwaterAIB, 0.8 ft/sec main streamvelocity32Worst-Case Aerial Scenario forCase Aerial Scenario forEach Habitat (1Each Habitat (1-Day Average)Day Average)NMFS: 15993 4021 13 ppb33Worst-Case Ground Scenario forCase Ground Scenario forEach Habitat (1Each Habitat (1-Day Average)Day Average)NMFS: 7.24.4 2.11.1 0.54 ppb34Conservative Features of ExposureAssessment3⁄4Assumed the water body is always directlyAssumed the water body is always directlydownwind of the treated areadownwind of the treated area3⁄4Wind speed is always 10 mphWind speed is always 10 mph3⁄4Conservative water body geometry andConservative water body geometry andflow/mass exchange conditions were selected,flow/mass exchange conditions were selected,where possiblewhere possible3⁄4Medium droplet size more likely to be commonMedium droplet size more likely to be commonin future for both air and ground applicationsin future for both air and ground applications3⁄4No degradation of chemical in water column orNo degradation of chemical in water column orsorption to sedimentsorption to sediment35ConclusionsConclusions3⁄4Well-accepted modeling and engineering methodologiesaccepted modeling and engineering methodologiescan be used to estimate concentrations in offcan be used to estimate concentrations in off-channelchannelhabitatshabitatszResults can be expressed as 1 or 2Results can be expressed as 1 or 2-day averageday averageconcentrations to match toxicity studiesconcentrations to match toxicity studies3⁄4We recommend evaluating additional data sets as theyWe recommend evaluating additional data sets as theybecome available to extend range of predicted outcomesbecome available to extend range of predicted outcomes36ReferencesReferences3⁄4Bryenton, A.G. 2007. Heat Balance of Alcoves on theWillamette River, Oregon. MS Thesis, Oregon StateUniversity, 77 p. Available online athttp://ir.library.oregonstate.edu/jspui/handle/1957/73863⁄4Giesy, J. P., Solomon, K. R. Coates J. R., Dixon K. R.,Giddings J. M., Kenega, E. E. 1999. Chlorpyrifos:Ecological Risk Assessment in North American AquaticEnvironments.Rev Environ Contam Toxicol160: 1-129.3⁄4Pasternack, G.B., Wang, C.L., Merz, J. 2003. Applicationof a 2D hydrodynamic model to design of reach-scalespawning gravel replenishment on the Mokelumne River,California,River Research and Applications, 19, 1-21.