Region 3 Exhibit 15..23.150000.Pdf

Erl;i,/-tt Exhibit l5

SETTINGAND ALLOCATING THECHESAPEAKE BAY BASINNUTRIENTAND SEDIMENTLOADS The ColaborativeProcess, Technical Tools and InnovativeApproaches

PRINCIPALAUTHORS Robert Koroncai Q.S. EnvironmentalProtection Agcncy RegionIII Philadelphia,PA

Lewis Linker U.S. EnvironmentalProtection Agency ChesapeakeBay Progtam Offrce Annapolis,Maryland

Jeff Sweeney Universityof Maryland ChesapeakeBay Program Annapolis,Maryland

Richard Batiuk U.S. EnvironmentalProtection Agency ChesapeakeBay ProgramOffice Annapolis,Maryland

U.5.Environmental Protection Agency Regionlll ChesapeakeBay Program Office Annapolis,Maryland

DECEMBER2OO3 cha pter I Background

For the pasttwenty years,the ChesapeakeBay Programpartners have been conmifted to achieving and maintaining water quality conditions necessaryto support living resource$throughout the ChesapeakeBay ecosystem.The 1983 ChesupeakeBay Agreementset the siage tbr the collaborative multi-state and federal partnership, and the 1987Chesapeake Bay Agreementset the first quantitativenutrient reduction goals (ChesapeakeExecutive Council 1983, 1987).With the signing of the Chesapeake 2000agteement (Chesapeake Executive Council 2000),the ChesapeakeBay Program partnerscommitted to: DeJiningthe water quality con.litionsnecessary to protect aquaricliving reaources and then assigning load reductions for nitrogen and phosphorus to each major lributary: arLd Using a processparallel to that establishedfor nutrients, deterrnining the sedimentload reductionsnecessary to achievethe wdter quality con- dilions that protecl aquatic living resources, and assigning load reductionsfor sedimentto eochmajor lributary. Through a six-state memorandum of understanding,the headwater states of Delaware,West Virginia andNew Yorkjoined Maryland,Virginia, Pennsylvania,the District of Columbia, the U.S. EnvironmentalProtection Agency (EPA) and the ChesapeakeBay Commissionin committing to restoreChesapeake Bay and river water quality throughthe adoptionof new cap load allocationsfor nitrogen,phosphorusand sediment(Chesapeake Bay WatershedPartners 2001). All the watershed partnersunderstood that these allocationsrepresented loading caps that must be achievedand maintained,even in the thce of increasinganthropogenic activities in thewatershed-

Using the best scientific informationavailable, Chesapeake Bay Programpadners have agreedto nutrient and sedimentcap loading allocations.On March 21, 2003 and April 15, 2003, the ChesapeakeBay ProgramPrincipals' Staff Committeeand representativesof the headwaterstates convened to adoptthe nutrient and sediment cap load allocationsand submergedaquatic vegetation (SAV) restorationgoals for the ChesapeakeBay (AppendixA)- The cap loads,allocated by major hibutarybasin

Lt'r.rpt{-'ri . Backqrcund and by statejurisdiction, will serveas a basisfor eachstate's tributary strategies that, whencompleted by April 2004,will describelocal implementationactions necessary to meetthe Crresapeake2000 nrstient and sedimentcap load allocationsby 2010.

This documentdescribes the scientificand technicalinformation and policy agreements that formed the basis for the important,comprehensive agreements that the ChesapeakeBay Programpartners made with regard to cap load allocationsfor nitrogen,phosphorus and sediments,as well as new baywideand local SAV restoration goals. The assessmenttools and techniquesevolved significantly over the allocationdecision-making process, therefore, it shouldbe notedthat this document is basedon the most recentinformation and proceduresused in supportof the cap load allocationdecisions that were made.

FUNDAMENTALSOF DEVEI.OPING CAP LOAD ALTOCATIONS

Cap loadallocations can be definedas cumulative pollutant loadings for all point and non-pointsources established and assigned to differentfibutary basinswithin a larger watershedthat, when achieved,will allow the receivingwater body to attain the prescribedwater quality goals.With the acc€lerateddevelopment of total maximum daily loads (TMDL$ over the recent years,the developmentof loading caps has becomecommonplace, but the sizeand complexity ofthe ChesapeakeBay watershed has madeallocation ofthe nutrientand sedimentcap loadssimilarly complex.

Typically, water quality goals are prescribed in stat€ water quality standards. I{owever,current statewater quality standardsaddressing nutrient- and sediment- related impairments for the ChesapeakeBay and its tidal fibutaries, which are based on nationalcriteria first publishedin the 1960sfor freshwatersystems, only address dissolvedoxygen. For this reason,the EPA,in direct consultationwith the watershed states,developed comprehensive, Chesapeake Bay regionalwater quality criteria for dissolvedoxygen, chlorophyll a and clarity, along with SAV restorationgoals for each segmentof the ChesapeakeBay and its tidal tributaries(U.S. EpA 2003a, 2003b).While at the time ofpublication of this documentthese criteria had not yet beenadopted into statewater quality standards,they were usedas the water quality basis for setting and allocating the nutrient and sediment cap loads for the Chesa- peakeBay watershed.

To determinethe appropriatecap loads and allocate them to individuat tributary basins,the pollutantsources must be relatedto impactson water quality.It is important to quantify the loadingsfrom all significant sourcesand to track the fate and hansportofthose pollutantsfrom the sourceto the Bay's tidal waters.In the caseof nutrlentsand sediments,the fate and transportmechanisms can be quite complex.

A complementarysuite of modelswas employedio simulatethe sources,tansport, fate and ultimate impact on tidal Bay water quality conditions of nutrient and sedimentloads. The airshedmodel was usedto track air sourcesfrom the 350,000- chaptor i - Backg()und square-mileChesapeake Bay airshedand the transportand depositionof atmos- phericnitrogen loads to the ChesapeakeBay watershedand directly to tidal surface waters.The watershedmodel trackedall sources-point, non-pointand air deposition within the watershedand simulatedthe fate of thosepollutants as they were transportedthrough the free-flowingriver systemsofthe watershedand deliveredto the tidal Bay waters.The water quality model, which is actually a compilation of severalmodels, then simulatedthe water quality impactsof thosepollutants on the water quality of the ChesapeakeBay and its tidal tributaries.

Knowing the water quality goals through the water quality criteria as applied within the refinedtidal-water designated uses and the reducedpollutrant loading effectson waterquality throughthe models,it waspossible to developdefensible, equitable cap load allocations.However, good sciencewas not enoughto derivethe cap load allocations.It was also importantto blend the scientificunderstanding with policy input to derive cap load allocationsthat not only could achievethe statedwater quality goals but also could gain considerablesupport from local shkeholdersultimately responsiblefor taking the actionsnecessary to reducenulrient and sediment loadings.

Policy input to settingthe cap load allocationswas most importantin determiningan appropriatedistribution of the allowablepollutant loads by major tributarybasin and jurisdiction. 'Fair and equitable'werethe basic principlesused by the Chesapeake Bay Programpartners in allocatingthe cap loads.Such subjectivequalities do not readily lend themselvesto technically based solutions without significant policy directionon how to achievethis desiredresult. Once the policy directionwas established on distributing the cap loads'fairly and equitably', a technical construct supportingthese policy principleswas developed.

KEY PLAYERSIN DEVELOPINGTHE ALLOCATIONS

The ChesapeakeBay Programcarries out its restorationand protectionfunctions throughan extensivecommittee structure led by the original ChesapeakeBay agree- mcnt signatoriesof Pennsylvania,Maryland, Virginia, the District of Columbia,the EPA and the ChesapeakeBay Commission(Figure I-l). For the developmentof water quality criteria, refined tidal-waier designateduse and cap load allocations, more than500 individualsrepresenting state, federal, regional and local govemment agencies,academic institutions, businesses, conservation organizations, community watershedorganizations, many othernongovemmental organizations, as well as the headwaterstates of New York, WestVirginia and Delawarejoined as full partners. Point sourcerepresentatives and environmentalgroups also were well-represented on the committeesduring this effort.An overviewofthe rolesofeach groupand the interplay betweengroups is describedbelow and illustratedin figures I-1 ard I-2. A brief review of the primary groupsis providedbelow.

WATERQUI\LIry TECHNICAL WORK6ROUP 'l l.risworkgroup consisted oftechnical staff and midlevel managersfiom the states, the EPA and stakeholdersfrom point source and environmental group interests and

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Figure l-1. chesapeakeBay program orqani?ational strudure. Source:Chesapeake Bay Program website http:/,/lJvww.chesapeakebay.net.

was expandedto include many of the modeling experts.Based on generalpolicy direction given by the Water Quality Steering Committee, the Water Quality Tech- nical Workgroup assessedmodeling results, explored options, developed the allocation methodology and made recommendationsto the Water euality Steering Cornrnittee on technical issues with regard to the allocations. The workgroup's efforts were supported by severalother groups:

' The Modeling Subcommitteemaintained and updatedthe watershedand water quality models used in the allocation effort and provided for all modeling analyses,including an ass€ssmentof the r€lative irnpact of pollutant loadings from the major basinson Bay water quality; the impact of nitrogenversus phos- phorusversus sediment inputs on Bay water quality; and all sensitivityand cap Ioad allocationproduction runs leadingup to the cap load allocations.

' The Nutrient Subcommittee developed the tiered scenarios and conducted an assessmentof sediment reduction effrciencies for near shore sedirnentreduction bestmanagement practices.

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Figurel-2. ChesapeakeBay Program partner's organizational structure supporting the developmentand adoption of the chesapeake8ay nutrient and sediment cap load allocations.

. The Living resourcesSubcommittee developed the baywide and local SAV restorationgoals. . The Monitoring andAnalysis Subcommitteeprovided technical input and tecorn- mendationson monitoring-relatedissues, including using a three-ycaraveraging periodfor all integratedmonitoring and modeling results to determineattainability. . The DissolvedOxygen Criteria,Water Clarity Criteria, Chlorophyll Criteria and WaterQuality StandardsCoordinators teams derived the watet quality criteriaand refinedtidal-water designated uses that wereas the basisfor settingand allocating the cap loads and developedthe cumulative fiequency distribution biological referencecurve approachto determiningcriteria attainment. . The UseAttainability Analysis Workgroupprovided input on where to apply the criteriathroughout the Bay tidal watersand providedinput on feasibilityand cost of ootions.

WATERQUATITY 5TEERING COMMITTEE This committeeconsisted of seniorwater programmanagers ftom all statesin the Bay watershed,EPA Headquartersand regions II and III, the ChesapeakeBay Commission.the SusouehannaRiver Basin Commissionand the PotomacRiver

cl].1p te. i - Background Basin Commission.In addition,representatives from the point sourceand environmental group interestsattended the meetings.The committee provided critical direction to the Water Quality TechnicalWorkgroup, which explored policy and technical issuesrelated to the restoring Bay water quality initiative. The issues exploredincluded the derivationof the Bay water quality criteria,the refinementof the tidal-waterdesignated uses, analysis ofthe attainabilityofcurrent andthe refined designateduses and the establishmenland allocationof nutrient and sedim€ntcap loads.The committeeselected the baywide nutrientcap loadsfrom variousoptions that the workgroup forwarded.The Water Quality SteeringCommittee ultimately forwardeda full packageofnuhient and sedimentcap load allocationrecommenda- tions to the Principals'StaffCommittee for reviewand formal adoption.

PRINCIPALS'STAFF COMMITTEE

The Principals'Staff Committee(PSC) consists ofthe secretariesofthe appropriate natural resource, agricultual, and fegulatory pollution control agencies for the original signatory states of Pennsylvania,Maryland, Virginia, the District of Columbia,the RegionalAdminisrrator ofEPA RegionIII and the ExecutiveDirector of the ChesapeakeBay Commission.While the headwaterstates of Delaware,New York andWest Virginia werenot membersof the committee,representatives of these statesattended PSC meetingsand were directly involved in all decisionsrelaied to the cap load allocations.The committeewas responsiblefor approvingthe allocations, but the PSC's involvement went well beyond approving th€ package recommendedby the WaterQuality SteeringCommittee. Since the recommendation of the Water Quality SteeringCommittee did not fully allocate the agreed-upon basinwidecap loads,the PSC and the headwaierstate representatives were called upon to negotiatethe allocation of the additional 12 milion pounds per year of nitrogenreduction and I million poundsper yearofphosphorus reduction nec€ssary to achievethe baywideloading caps.

REEVALUATING THE ALLOCATIONS

The nutrientand sediment cap loadallocations adopted by the sevenwatershedjuris- dictions and EPA are the best scientific estimatesof the annual load reductions neededto attain proposedwater quality criteria and tidal-water designateduses describedin the lrrl bient WaterQuality C teriafor Dissolved Orygen, W'aterClarity and Chlorophyll a for the ChesapeakeBay and I* Ttdal Trtbuturies (Regional Crileia Guiclance)published by the EPA (U.S. EPA 2003a). Over the next two years,Maryland, Virginia, Delawareand the District of Columbia will promulgate new water quality standardsbased on the regionalguidance published by EPA.

Although the public processfor adoptingwater quality standardsvaries among the states,each state's process will provide opportunitiesfor consideringand acquiring new lnformation at the local levbl. Statesmay chooseto exDlore a number of issues

ch;r ptcr i - Background during their adoptionprocess, such as the economic impact of water quality stan- dardsand specificdesignated use boundaries.

While the allocationsadopted at this time will providethe basisfor tributary strategies, theseallocations may need to be adjustedto reflect final statewater quality standards.Furthermore, planned Bay model refinements,designed to estimatewater quality benefitsfrom filter feeding resources(such as oystersand menhaden)and improve understandingof the sourcesand effects of sediments,will increasethe partners'understanding ofthe relationshipbetween nutrient and sedimentreductions and living resourceresponses in the ChesapeakeBay. For thesereasons, th€ states and EPA ageed to a reevaluationofthese cap load allocationsby no laterthan 2007-

As partners,the jurisdictions committedto correcting the nutrient- and sediment- relatedproblems in the ChesapeakeBay and its tidal tributariesenough to remove them from the list of impairedwaters by 2010 underthe CleanWater Act. The states recognize,however, that it will be dillcult to meet projected water quality standards in all partsof the ChesapeakeBay tidal watersby that time.A key reasonfor this dif- ficulty is that once nutrient and sediment reduction practicesare installed and implemented,it may be yearsor evendecades before the ChesapeakeBay benefits from thesereductions. The jurisdictionsintend to haveprograms in place.andfunc- tioningby 2010.The ChesapeakeBay and its tidal tributariesare expected to become to be eligible for delisting when nutrient and sedimentprograms are fully imple- mentedin the basin.

SUPPORTINGDOCUMENTS

In addition to recognizingthe need for cap load allocationsfor nutrientsand sediments, Chesapeake2000 also acknowledgedthe need for the developmentof scientifically soundwater quality criteria for the protection ofthe ChesapeakeBay's living resources llom nutrient- and sediment-relatedimpacts. Through exlensive scientific research, parher involvement and stakeholder and scientific review, the EPA has published regional water quality criteria for the ChesapeakeBay and its tidal tributaries for dissolvedoxygen, water clarity and chlorophyll a. A full descriptionof thesewater quality criteria can be found in the Regionql Criteria Guidance (U.5. EPA 2003a).

To support the Regional Criteria Guidance, the EPA has published lhe Technical Support Document for the ldentiJication of ChesapeakeBay Designated Uses and Attainability (TechnicalSupport Document) (U.S. EPA 2003b).The purposeof the TechnicalSupport Document is Io identiff new refinedtidal habitatzon€s, or designated uses, to which the ChesapeakeBay criteria will apply. In addition, SAV restoration goals have been esiablishedby the Chesapeak€Bay Program partners for segmentstkoughout the ChesapeakeBay tidal waters.The TechnicalSupport Docu- ment also delineatesthe boundariesof these designateduses and assessestheir technologicalattainability. The EPA also has published a companion document entitledEconomic Analysis and Impactsof Nutrient and SedimentReduction Actions

ch.rptt.-r i . Ba.kground to RestoreChesupeake Bay WaterQuality, which providesinformation on costsand impactsof variouslevels of nutrientand sedimenttechnology and bestmanagement pmcticescontrols across the ChesapeakeBay watershedthat may be necassaryto meet the new criteriaand designateduses (U.S. EPA 2003c).

Collectively,these three documents support the establishmentofcap load allocations for nutrientsand sedimentsby identifying attainablewater quality and resource restorationgoals for all habitatswithin the ChesapeakeBay and its tidal tributaries.

A memorandumfrom SecretaryTayloe Murphy (2003),Virginia Natural Resources Secretaryto the Principals' Staff Committeemembers and representalivesof the ChesapeakeBay headwaterstates formally summarizedthe decisionsregarding the nutrient and sedimentcap load allocationsand the new submergedaquatic vegetation restorationgoals-

A memorandumfrom SecretaryTayloe Murphy (2003),Virginia Natural Resources Secretariate,to the Principals'Staff Committeemembers and representativesof the ChesapeakeBay headwaterstates formally summarizedthe decisionsregarding the nutrientand sedimentcap load allocationsand the new submergedaquatic vegetation restorationgoals.

ORGANIZATIONOF THE ALLOCATIONSDOCUMENT

The cap load allocationswere basedlargely on a scientific understandingof what affectsth€ water quality of the ChesapeakeBay and its tidal tributaries.Therefore, much of this documentis dedicatedto presentingthe scientifictools and issuesthat were important to the developmentof the allocations.Accordingly, Chapter II reviewsthe primary tools usedin developingthe cap load allocations,including the loadingscenarios. These scenados were usedto estimatethe nutrient and sediment loads associatedwith increasedlevels of pollution control measuresand to gain insight into the sourceloadings and associated impacts on water quality.In addition, this chaplerprovides a brieftechnicalreview of the variousmodels used to simulate the sourceloads and their impacton the Bay's tidal water quality.

ChapterIII reviews the major technicaldiffrculties that fiose and documentsthe innovativesolutions crealed by th€ partners'technical staff. Includedin this chapter are issuesrelated to developingthe methodologyfor determiningattainment of the water quality criteria (e.g.,applying biological referencecurves), results of assessmentson the impact ofeach major basinon the Bay's tidal water quality,results of assessmentson the water quality impact fiom nitrogenversus phosphorus inputs to the Bay (e.g., analyzingrelative effectiveness)and a brief technicalreview of the attainmentsimulations for the SAV acreagegoals established for the Bay.

Howwer, signihcantpolicy guidancewas vital in order to arrive at cap load alloca- 'buy-in' tions with the highest probability of and, therefore, th€ greatestassurance of implementation.Chapter IV describeshow scienceinformed the policy decisions

.h.r ptcr i . BJckgrou nd appliedduring the cap load allocationprocess. It providesa detailedreview of the methodologies.model results and policy decisionsused to derivethe cap load allocations for nutrientsand sediments.Specifically, it presentsthe principlesapplied and approachestaken to derivebaywide loading caps for nutrientsand sedimentand the two separdtemethodologies used to distribute the cap loads to the major tnburary basinsand then tojurisdictions within the Bay watershedfor nutrientsand sediments.

Finally, appendicesA through F provide extensivemodel resultsand analysesin supportof the allocations.

IITERATURECITED

ChesapeakeBay WatershedPartners. 2001.

ChcsapeakeBay ExecutiveCouncil. 2000. Chesapeake 2000 agreement.Annapolis, Maryland,

ChesapeakeBay Executive Council. 1987. CheoapeakeBey Agrcement. AnrLapalis,Maryland.

ChcsapeakeBay Executive Council 1983. ChesapeakeBay AgreemenL Annapolis, Maryland, SecretaryTayloe Murphy. 2003. "Summary of DecisionsRegarding Nutrient and Sediment Load Allocationsand New SubrnergedAquatic Vegetation(SAV) RestorationCoals." April 25, 2003, Mernorandumto the Principals'Staff Committeemembers and representativesof the ChesapeakeBay headwaterstates. Virginia Office of the Covemor, Natural Resources S€cretariate,Richmond, Virginia.

U.S. EPA. 2003a.Anbient WaterQuality Criteriafor DissolvedOxygen, Warer Clarity and Chlorcphyll aJor the ChesapeakeBay and IB ndal Tributuies. EPA 903-R-03-002.Chesa- peakeBay ProgramO{fice, Annapolis, Maryland.

U.S. EPA. 2O03b. Technical Support Document for the ldentiJication of ChesapeakeBay DesignaledUses and Attdinabilttl. EPA 903-R-03-004.Chesapeake Bay Ptogram Office, Annapolis,Muryland.

U.S. EPA. 2003c. Economic Analysis aad lmpacts of Nutient and Sediment Reduction ]lctiotts to Restore Chesapeake Bey ll/ater SualitJ. Chesapekc Bay Program Offrce, A nnapolis,Maryland. http ://www.chesapeakebay.net/ecoanalyses.htm.

ch;r ptc-r i . Background Contents

Acknowl€dgment3 vll

Executiv€Summary xi CHAPTERI Background I Fundamentalsof DevelopingCap Load Allocations Key Phyers in Developing the Allocations 3 WaterQualiry TechnicalWorkgroup WaterQuality SteeringCommittee 5 Principals'Staff Committee 6 Reevaluatingthe Allocations 6 SupportingDocuments 7 Otganization of the Allocations Document 8 .. Literature Cited 9

CHAPTERII Overview of the TechnicalTools .. u Tiered Management Implemeniation Scenarios ll Developmentof the Tiered Scenarios l3 Tiered ScenarioEstimated Nutrient and SedimentLoads ...... l5 ChesapeakeBay Program Environmental Models t7 ChesapeakeBay Airshed Model andAtmospheric Deposition . . . l9 ChesapeakeBay WatershedModel . . . ChesapeakeBay Wat€r Quality Mod€l 29 Hydrodynamic Model . WaterQuality Model ..... 3l Adjustmentof Model DissolvedOxygen, Water Clarity and Chlorophyll .r Estimates ManagementApplication of Model Outputs . . 36 Literature CIted . . .. . 39 Contenls M./ {

CHAPTERIII Technicaland ModelingConsiderations in Settingthe Allocations . . 43 43 44 AssessingMonitoring Data 44 AssessingModeling Data 44 Delining Allowable Frequency and Duration of CriteriaExceedances ...... 46 Establishing the Geographic Influence of the Loads on TidalWater Quality ...... - 48 Focusingon MainstemSegments CB3MH, CB4MH andCB5MH ....,-,,.. 48 ComparingAbsolute Versus Relative Eflectiveness ...... 48 Normalizingfor the CornbinedNitrogen and PhosphorusLoad . . 49 GeneralFindings from theGeographic Isolation Runs ...... 51 Establishing Wetland Influence on Tidal-Water DissolvedOxygenConcentrations ...... 54

Water Quality Model Runs Isolating Individual PollutantEffects on WaterQuality ...... 54 SurfaceAnalysis Plots . . . 54 SurfaceAnalysis Utility ...... , 56 Influence of Sedimentationon ChesapeakeBay DissolvedOxygen . Establishlng and Ass€ssingthe N€w SAV Restoration Goals . . . . . 60 Developingthe 185,000-Acre SAV Restoration Goal ...... 6l WaterClarity and SAV ...... 65 SedimentLoads: Local Effects ...... 67 Calibratingthe WaterQuality Model for Clarity ...... 68 RelatingSAV Biomass to Acreage . . . . . -...... 70 SpatialAnalysis of EffectiveShoreline Load Reductions ...... 74 MonitoringApproach ,... .,..... 78 SedimentCap Load Allocation Principles ...... 78 Lit€ratureCited

Contents CHAPTERIV Settingthe Nutrientand SedimentAllorations ._...... gl EstablishingNutri€nt Cap LoadAllocations ...... 82 CeographicLocation and Criterion Driving the Allocation . . . . . 82 BaywideCap Loading Options ...... 83 DistributingBasinwide Allocations to the MajorBasins and Jurisdictions ...... 9l ThePSC Completes the Allocation Process...... 99 Cap Load Allocationsto Achieve the Chlorophyll a Criteria . . . . 99 Additional Nutrient Cap Load Allocation Considerations...... 103 EstablishlngSediment Cap LoadAllocations ...... 103 SAVRestoration as the Coal .....103 Land-Based(Upland) Sediment Allocation ...... 104 EslablishingNear-Shore Sediment Allocation ...... 105 SAV-BasedSediment Cap Load Allocarions ...... 106 Summary of Nutrient and Sediment Cap Load Atlocations . . . . . 106 LiteratureCited ..110

APPENDICES

Appendix A: Summaryof DecisionsRegarding Nutrient and SedimentLoad Allocations and New Submerged Aquatic Veg€tation(SAV) Restoration Goal$- Memorandumfrom W TayloeMurphy, Jr., Chair, ChesapeakeBay ProgramPrincipals' Staff Committee, to the Principals'Staff CommitteeMembers and ..Headwatef' Representaiivesof Chesapeake Bay States...... Al

Appendix 8: Summaryof Water Quality Criteria and Use BoundariesUsed in Setting the Allocations ...... B I Appendix C: Summary of Watershed Model Results forAll LoadingScenarlos ...... Cl Appendix D: Summaryof Key Attainment Scenarlos DI

Contents 'w ,f !

Acknowledgments

nevelopment- of the nutrient and sedimentallocations for the ChesapeakeBay l-rfinvolved sifiing througha wealthofscientific dataand information,constructing a technicallysound decision making processand factoringin an aray ofpolicy considerations.The collaborativeefforts, collective knowledge -andand appliedexperiise ot the following committees,subcommittees. workgroups, heaiwarerrepresenra- tiveswere contributedto th€ successof the process.

Developmentof the technicalrecommendations that met the diverseneeds of the ChesapeakeBay Programpartners would not havebeen possible without the under- standingofwater quality conditionneeds of the Bay.energy and enthusiasm,which was provided by membersof and staff to the ChesapeakeBay program Water Quality Technlcal Workgroup: Alan Pollock, Ctraia Virginia Diiartment of -EnvironmentalQuality; RichardBatiuk, U.S. EpA ChesapeakJBayprogram Office; Victor Bierman, Jr., LimoTech Inc.; Michael Bowmar1 Virginia De-partmentof Conservation& Recreation;Charles Lunsford, Virginia Departirentofionservation & Recreation; William Brown, pennsylvania Department of Environmental Protection; -Arthur Butt, Virginia Department of Elnvironmentaleuality; John Kennedy,Virginia Departmentof Environmenialeuality; JamesColliir, Disirict of Columbia Department of Health; Carol young, pennsylvania Department of Environmental Protection; Richard Drapeg New york State Deiartment of Environmental Conservation; Richard Eskin, Maryland Deparhnentof Environment; DaveMontali, WestVirginia Departmentof Environmentaiprotection; Will Hunley, Hampton Roads Sanitation Dishict; Maggie Kerchner,NOAA ChesapeakeBay Offce; Wendy Jastremski,U.S. EPA ChesapeakeBay program Offrce; Robert Korolcai, US,. EPA ChesapeakeBay ProgramOfiicet Norm LeBlanc, Hampton RoadsSanitation District; Lewis Linker, U.S. EpA ChesapeakeBay programOlirce; Russel Mader, National Resources Conservaiion Siwice; Roberi Magnien, Maryland Department of Natural Resources; Lee McDonnell, pennsvlvania Depadmentof EnvironmentalProtection; Mark Morris, U.S. EpA Office of Water; Scott Phillips, U.S. Geological Suwey; Ana pomales, U.S. EpA Region III; Pomeroy, 9,M"qp!". Aqualaw PLC; John Schneider, Delaware Depariment-Chesapeake of Natural Resources& Environmental Control; Ga.ry Shenk, U.S. EpA Bay Program Oflice; Tom Simpson, University of Maryland; Tanya'Maryland Spano, Metropolitan petli - Washington Council of Govemments; Tango, DepartmentofNahrral Rcsources;Lyle Vamell,Virginia Instituteof Marine Science; Lauren Wenzel, Maryland Departmentof Naturai Resources;Allison Wiedeman, y I Et+ ChesapeakeBay Program Office; Clyde Wilbur, Greeley & Hanseq and Kyle Zieba, U.S. EPA ChesapeakeBay program Ofiice.

n cknowleLjgmcnts vulif :f

Developmentofth€ nuhient and sedimentcap load allocationswould not havebeen possible without the ability to understandthe water quality and living resource responsesto pollutant loadings in the Bay. Such understandingis made possible throughthe ChesapeakeBay Airshed,Watershed and WaterQuality models,which are ably managed,maintained, and continually enhancedby members of the ChesapeakeBay Program'sModeling Suttcommittee:James Collier, Chair,District of Columbia Departmentof l{ealth; Lowell Bahner,National Oceanic& Atmos- pheric Administration; Mark Bennett, U.S. Geological Suwey; Peter Bergstrom, U.S. Fish & Wildlife Service; Michael Bowman, Virginia Departmentof Conservation& Recreation;William Brown, PennsylvaniaDepartment of En- vironmentalProtection; Arthur Butt, Virginia Departmentof EnvironmentalQuality; Robin Dennis, National Oceanographicand AtmosphericAdministration; Lewis Linkeq U.S. EPA ChesapeakeBay Program Ofiice; Chades Lunsford, Virginia Departmentof Conservation& Recreation;Robert Magnien, Maryland Department of Natural Resources;Ross Mandel, InterstateCommission on the PotomacRiver Basin; Timothy Murphy, Metropolitan Washington Council of Governments; Narendra Pandan Maryland Department of Environment; Kenn Pattison, PennsylvaniaDeparfnent of EnvironmentalProtection; Jeff Raffensperger,U.S. Geological Survey-Baltimore;Helen Stewart, Maryland Departmentof Natural Resources; Peter Tango, Maryland Department of Natural Resources; and Harry Wang,Virginia Instituteof Marine Science.

While all of the Modeling Subcommitteemembers made important contributions, specialrecognition is appropriaielydue to Lewis Linker (EPA), Cary Shenk(EPA) and Jeff Sweeney(University of Maryland) lor pioneeringefforts in creatingnew approachesto diffrcult problemsthrough relentlessdedication to th€ task at hand' Specialthanks and rccognitionto Ping Wang(University of Maryland) for his skill, expertise,and dedicationin scenariooperation and developmenton The National Environmental Super Computer Center, and to Kate Hopkins (University Of Maryland) for her expert application of GIS modeling support to the allocation analyses.

The sediment allocation recommendationswere driven by the new Submerged Aquatic Vegetation(SAV) restorationgoal. Without the close coordinationbeaween the ChesapeakeBay Program'sSAV Workgroup and the WaterQuality Technical Workgroup,linking the SAV resourceto the sedimentcap load allocationswould not havebeen possible. Mike Naylor (MarylandDepartment of Natural Resources),Ken Moore (Vitginia Instituteof Marine Science),Frank Dawson (Maryland Deparfinent of Natural Resources)and Mike Fritz (EPA) in particular, led the effort to assure integration of the SAV restoration goal with efforts to derive water clarity criteria, set shallow-waterdesignated use boundariesand establishthe sedimentcap load allocations.

The ChesapeakeBay Program'sScientilic and Technical Advisory Committ€e (STAC)provided timely and importantinput to the allocationprocess during a critical junchrre in the deliberations.Special thanks to Scott Phillips for his leadership in facilitating communication between STAC and the Water Quality Technical Workgroup.

Cap load allocations,especially as complex as that for the ChesapeakeBay, are a uniqueblend ofscienceand policy. The ChesapeakeBay Program'sWater Quality Steering Committee provided much needed direction to the Water Quality

Acknowlcdgcments TechnicalWorkgroup on difficult mattersof€quity andprocess. Furthermore, it was the Water Quality SteeringCommittee that forwardedthe cap load allocationsto the Principals' Staff Committee for approval.The memberswere: Jon Capacasa, 9o-chair,U.S. EPA Region III; RebeccaHanmer, co-chair, U.S. EpA Chesapeake Bay Program; Russell Baxter, ChesapeakeBay Commission;Jerusalem Bekele, District of ColumbiaDepadment of Health;Michael Bowman.Virsinia DeDarfinent of Conservation& Recreation;Edward Brezina. pennsvlva-niaDeoartment of EnvironmentalProtection: Patricia Buckley, pennsylvaniaDepartment of Environmental Protection; William Brannon, W€st Virginia Department of EnvironmentalProtection; James Collier, District of Columbia Departmentof Ilealth; Melanie Davenport, ChesapeakeBay Commission; Kevin Donne y, Delaware Departmentof Natural Resourceand EnvironmentalControl: Richaid Dra-per,New York State Departmentof EnvironmentalConserrration; phillip M. Decaetano, New York State Departmentof EnvironmentalConservation; Mario DelVicario, U.S. EPA RegionII; Diana Esher,U.S. EpA ChesapeakeBay pmgram Olftce; Richard Eskin, Maryland Departmentof the Environment; jack Frye, Virginia Departmentof Conservationand Recreation;Stuart Gansell, pennsvlvania Departmentof EnvironmentalProtection; Carlton Haywood,Interstate Commission on the PotomacRiver Basin;David Heicher,Susquehanna River BasinCommission; JamesKeating, U.S. EPA Office of Water,Oflice of Scienceand Technology;Felix Locicero, U.S. EPA Region II; Steve Luckman, Maryland Departmenl of the Environment;Robert Magnien, Maryland Departmentof Natural Resources;Chris Miller, U.S. EPA Offrce of Water, Offce of Scienceand Technology;Matthew Monroe, West Virginia Departmentof Agriculture; Kenn pattison,Finnsylvania Departmentof EnvirorunentalProtection; Alan pollock, Virginia Departmentof EnvironmentalQuality; John Schneider, Delaware Department ofNatural Resources and EnvironmenlalControl; Thomas Simpson, University of Maryland; Robert Summers,Maryland Departmentof Environment;Ann Swanson,Chesapeake Bay Commission; Robert Yowell, Pennsylvania Department of Enviionmental Protection;and RobertZimmerman, Delaware Deparhnent ofNatural Resourcesand EnvironmentalControl-

Withoul a unified commitmentto restoringthe ChesapeakeBay, agreementon allocating the last 12 million poundsof nitrogenand I million poundsof phosphorus that is necessaryto achievethe basinwidecap loadswould nbt havebeen poisible. The ChesapeakeBay ProgramPrincipals' Staff Committeealong with its niw partner statesof Delaware,New York, and WestVirginia, providedthe leadershipthat was nec€ssaryto approvethe allocation recommendationsand to allocate further remainingloads.

Principals'Staff Committee W. TayloeMurphy, Jr., Secretaryof Natural Resources,Mrginia, Office of Covernor(Chair) JosephMaroon, Director,Virginia Departmentof Conservationand Recreation RobertG. Bumley,Director, Virginia Departmentof Environmentaleuality TheodoreJ. Gordon,Chiefoperating Officer, District of ColumbiaDepartment of Health ElizabethBerry, SpecialAssistant, Executive Office of Mavor. District of Columbia

Acknowiedgments Lewis R. Riley, Secretary,Maryland Departmentof Agriculture Lynn Y Buhl, Acting SecretaryMaryland Departrnent of the Environment C. Ronald Franks, Secretary,Maryland Department of Natural Resources Audrey E. Scott,Secretary Maryland Departmentof Planning KathleenA. McGinty, Secretary,Pennsylvania Department of Environmental Protection Michael DiBerardinis,Secretary, Pennsylvania Department of Conservation& NafuralResources RichardG. Sprenkle,Deputy Secretary,Pennsylvania Department of Conservation andNatural Resources Ann Swanson,Executive Director, Chesapeake Bay Commission Donald S. Welsh,Regional Administrator, U.S. EPA RegionIII RebeccaW. Hanmer,Director, U.S. EPA ChesapeakeBay ProgramOffrce

HeadwaterState Representatives William Brannon,West Virginia Departmentof EnvironmentalProtection Matthew Monroe, West Virginia Department of Agriculture RichardDraper, New York StaieDepartment of EnvironmentalConservation Kevin Donnelly,Delaware Department ofNatural Resourcesand Environmental Conservation

Acknowicdgmcnts ExecutiveSummary

lhe Chesapeake)000 agreementhas been guiding Maryland, pemsylvania, I Virginia, the District of Columbia, the ChesapeakeBay Comrnissionand the U.S. EnvironmentalProtection Agency (EPA) in their combinedeforts to restore ..achieve and protect the ChesapeakeBay. It definedthe goal to and maintain the waterquality necessaryto supportthe aquaticliving resourcesofthe Bay and its tributariesand to protecthuman health." Subsequently, Delaware, New york and West Virginia signed a Memorandumof Understandingcommitting to implement the WaterQuality Protectionand Restorationsection of the agreement. Chesapeake2000 committedits signatoriesto:

conlinueeforts to achieveand, maintain the 40 percentnutrient reduction goal agreed to in 1987 and correct the nutrient- qnd .rediment-related problems in the ChesapealceBay and its tidal tributaries sujJicienlly to remoye the Bay and the tidal portions ol its tributaries from the list of impaired waters under the Clean WaterAct by Z0lO. Defining science-basedloading caps for nutrients and sediment and allocating responsibilityby major tributary basin to the jurisdictions were critical steps to fulfilling the water quality commitments.This documentpresents the collaborative process,technical tools and innovativeapproaches that madepossible the successful allocationof nuhient and sedimentcap loadsto eachjurisdiction by major tributary basin.

NUTRIENTCAP LOAD ALLOCATIONS Excessivenutrients in the ChesapeakeBay and its tidal tributariespromote a number ofundesirablewater quality conditionssuch as excessive algal growth, low dissolved oxygenand reducedwater clarity.The effect of nutrient loadson water quality and living resourcestends to vary considerablyby seasonand region. Low dissolved oxygenproblems tend to be more pronouncedin the deeperparts of th€ upperbay region during the summer months.The allocationsfor nutrients were develooed primarily to addressthis problem.

As a result,New York, Pennsylvania,Maryland, Delaware, Virginia, WestVirginia, the District of Columbia and the U.S. Erwironmentalprotection Agency agreedto cap annualnitrogen loads delivered to the Bay's tidal watersat 175 million pounds

Execlttive5u mmary and annualphosphorus loads at 12.8million pounds.It is estirnatedthat theseallocations will require reductions,from 2000 levels, in nitrogen pollution by 110 million poundsand phosphoruspollution by 6.3 million pounds. The ChesapeakeBay Programpartners agreed to theseload reductionsbased upon ChesapeakeBay WaterQuality Model projectionsof attainmentof publishedBay dissolvedoxygen criteria applied to the refined tidal water designateduses. The model projectsthese load reductionswill significantlyreduce the petsistentsummer anoxicconditions in the deepbottom watersof the ChesapeakeBay andrestore suit- able habitat quality conditions throughout the tidal tributaries. Furthermore, these reductionsare projected to eliminateexcessiv€, sometimes harmfirl, algae conditions (measuredas chlorophylla) throughoutthe ChesapeakeBay and its tidal tributaries. Thejurisdictions agreed to distributethe basinwidecap loadsfor nitrogenand phos- phorusby major tributarybasin (Table l) andjurisdiction(Table 2). This distribution of responsibilityfor load reductionswas based on threebasic principles: l. Tributarybasins with the highestimpact on ChesapeakeBay tidal waterquality would be allocatedthe highestreductions of nutrients. 2. Stateswithout tidal waters-Pennsylvania,New York and West Virginia- would be providedsome relief from Principle I sincethey benefitless directly from improvedwater quality in the ChesapeakeBay and its tidal tributaries. 3. Nutrientreductions prior to 2000 would be creditedtowards achievement ofthe cap load allocations. The nine major tributarybasins were separatedinto threecalegories based upon their impact on Bay tidal water quality. Each basin within an individual categorywas assignedthe same percent reduction of anthropogenic,or human-caused,load- Consequently,basins with the highestimpact on tidal water quality were assigned the highestpercentage reduction of antkopogenicload. A{ier completingthe abovecalculations and applyingPrinciple 2, New York, Penn- 'Tier sylvaniaand WestVirginia allocationswere set at the 3'scenario nutrientload levels.The Tier 3 scenariois one of severaltiers representingdifferent implementation scenarios of nutrient reduction measures for the ChesapeakeBay watershed developedby the ChesapeakeBay Programpartners. ThE Tier 3 scenariorepresenied nutrientand sedinlentloads of 181million poundsofnitrogen per year, 13.4million poundsof phosphorusper yeart 4.14 million tons of land-basedsediment per year and includeda 20 percentreduction in tidal shorelineerosion sediment loads' Addi- tionally,allocations forVirginia's York andJames River basinswere set at previously establishedtributary strategynutrient cap load levelssince these two basinshave a minimal impact on mainstemBay water quality conditions,and their influenceon tidal water quality is predominantlylocal. Application ofthese rulesresulted in shortfallsof l2 million poundsofnitrogen and I million poundsof phosphorusabove the basinwidecap loads.However, the EPA committedto pursue the Clear Skies initiative, which is estimatedto reducethe nitrogenload to Bay tidal watersby 8 million poundsper year-Furthermore, the Bay watershedstates agreed to takeresponsibility for the remaining4 million poundsof nitrogenand I million poundsof phosphorus.The nutrient cap load allocationsin tables L and 2 reflect theseagreements.

Exccutivp5Lrmmary The cap load allocationsfor nitrogen and phosphoruswere adoptedas .nitrogen equivalents'-Included was a commitmentto explorehow actionsbeyond traditional best manag€mentpractices (BMPS) might help meet the ChesapeakeBay water quality restorationgoals. A nihogen equivalentis an action that resultsin the same water quality benefitas removingnitrogen. The ChesapeakeBay programpartners will evaluatehow tidal water quality benefitsfiom continuedand expandedliving resourcefestoration, such as oystersand menhaden,can be accountedfor in offset- ting the reductionsof watershed-basednutrient and sediment loads. Seasonal fluctuations in implementationof biological nutrient removal, nutrient reduction from shorelineerosion control, implementationof enhancednutrient removaltech- nologiesat largewastewatcr treatment plants, and trade-offsbetween nitrogen and phosphoruswill alsobe evaluated.

Also, while the allocationsadopted at this time will provide the basisfor tributary strategies,these allocations may need to be adjustedto reflect final staie water quality standards.Ifthe final adoptedstate water quality standardsare different than the criteria and designateduse usedto establishthese cap load allocations.then the cap load allocationswill needto be amendedaccordingly.

SEDIMENTCAP I.OAD ALLOCATTONS

Sedimentssuspended in the water column reducethe amount of light availableto support healthy and extensive submergedaquatic vegetation (SAV), or underwater bay grass,communities. The relativecontribution of suspendedsediment and algae that causepoor light conditionsvaries with location in the Bay tidal waters.The ChesapeakeBay Programpartners agreed that a primary reasonfor reducing sediment loadsto the Bay tidal watersis to provide suitablehabitat lor restoringSAV. As a result,the cap load allocationsfor sedimentsare linked to the recommendedwater clarity criteria and the new SAV restorationgoals and recognizethat sedimentload reductionsare essential to sAV r€storation.The jurisdictions also agreedthat nutrient load reductionsarc citical for restoringSAV as well as improvingoxygen levels. To support the sedimentcap load allocations,it becameclear that updatedSAV restorationgoals were needed.The partnersexplored various methodologiesfor developinga baywide SAV acreagerestoration target using the availablehistorical record.The methodologyselected used aerial photography from the l9l0s to present to identify the besty€ar of record(in terms of acresof SAV) for eachChesapeake Bay Programsegment. The acreagedetermined to be the best year of record was designat€das the SAV acreagegoal for that segment.In aggregatingall ofthe single bestyear resultsfor eachsegment, a baywide SAV acreagerestoration goal for the entireBay of 185,000acres was established.Table 3 providesthe SAV acreagegoal for each Bay segmentwhile Table 4 provides the SAV acreagegoal for each major tributary basin in the ChesapeakeBay watershedadopted by the ChesapeakeBay Program partners.

Unlike nutrients,where loads from virtually the entire ChesapeakeBay watenhed affect mainstemChesapeake Bay water quality, impacts from sedimentsare pre- dominantly localized.For this reason,Iocal, segment-specificSAV acreagegoals have been establishedand the sedimentcap load allocationsare taryetedtowards achievingthose restoration goals.

Executive5u mrnary The partners recognize that the current understandingof sediment sourcesand their impact on the ChesapeakeBay is not yet complete. Currently, understandingof land- based sediments that are carried into local waterways through stream bank erosion and runofl is still basic. Knowledge about nearshoresediments that enter the Bay and its tidal rivers difectly through shoreline erosion or shallow-water suspensionis even more limiied. Consequently,the sedimentcap load allocations are curently focus€d on land-basedsediment cap loads by major tributary basin (Table l) and jurisdiction (Table2). Most land-basedbest managementpractices, which reduce nonpoint sourcesof phosphorus,will also reduce sediment runoff. Therefore, the partnersagreed to land- basedsediment allocations that representthe sediment load reductionslikely to result from implementing managementactions required for the allocatedphosphorus reductions. The sediment cap load allocations were set at the tier lwel for the phosphorus cap 'phos- loadallocation for eachjurisdiction-basin.This designationis referredto asthe 'phosphotus phorus equivalent' land-based sediment reduction. If the equivalent' land-basedsediment reductions were found to be more than that which are necessary lo achievethe local SAV restoration goals,then the land-basedsediment cap load allocations were lowered to that level necessaryto achievethe SAV restoration goal. The tidal-fresh SusquehannaFlats and tidal-fresh Potomac River are two exampleswhere this modified approachwas applied. If, in the developmentof their tributary strategies, tributary teams conclude that the land-basedsediment allocations need revisions, the tributary teams may identiff an altemate land-basedallocation. For example,ajurisdiction may selectdifferent nonpoint source management actions than those prescribed in the tier approach to reach the phosphorus goal; the jurisdiction may adjustthe sedimentcap load allocationaccordingly so long as SAV restoration and protection is not compromised.The tributary teams must work with all the jurisdictions within the afected basin in revising the sediment cap load allocations. It is likely that reductionsin nutrientsand land-basedsediments alone will not be suffrcientto achievethe local SAV restorationgoals for many areasof the Chesa- peake Bay and its tidal tributaries. In these areas, tributary leams will be asked io further assessvaried and innovative methods to achieve SAV establishment and growth. Such methodsmay include, but are not limited to SAV planting, offshore breakwaters,shore erosion controls, beach nourishment,establishment of oyster bars,and other actionsas appropriate.

ExecutiveSummary Table1. ChesapeakeBay watershed nitrogen, phosphorus and sedimentcap loadallocations by majorbasin.

Nitrogcn Phosphorus Uplard Sediment Cap Load Allocation Cap LoNd Allocation Cap LoadAllocation Bssir/Jurisdictiotr (million pounds/yeff) (million pounds/yerr) (million tons/year) SUSQUEHANNA PA 67.58 1.90 0.793 NY 12.58 0.59 0.131 MD 'Iotal 0_83 0.01 0.01'l SUSQUEI{ANNA n0.99 2.52 0.962 EASTERNSHORE - MD MD 10.89 0.81 0.1t6 DE 2.88 0.30 o.042 PA 0.2'1 0.03 0.004 0,06 0.01 0.001 EASllil{N S[{ORE- MD lbral t4.l0 l.t4 0.l6l WESTERNSHORE MD r t.27 0.84 0.100 PA 0.02 0.00 0.001 WESlt.lRN SIIORE Total I1.29 0.84 0.100 PATUXENT MD 2.46 0.21 0.095 PAIUXENT Total 2.46 0.2| 0.095 POTOMAC 12.84 1.40 o.6t't MD I 1.81 1.04 0.364 4.7| 0.36 0.31I PA 4.O2 0.33 0.t97 DC 2.40 o.34 0,006 POTOMAC'lotul 35.78 1..18 I .494 RAPPAHANNOCK s.24 0_62 0.288 R.APPAtIANNOCKToral 5.)4 0.62 0.288 YORK 5.70 0_4E 0.103 YOIt K fotaI 5.70 0.48 0.L0l JAMES 26.40 3.41 o.925 0.03 0,01 0.010 Jr\lvlES'fotal 26.43 0.935 EASTERNSHORE . VA 'tbt.rl L16 0.08 0.008 tlAS'fLRNSIIORE - V' t.t6 0.08 0.{.108

SUBTOTAL 183 t2.8 4.15 CLEAR SKIES REDUCTION -8 'I'O B,\SINWIDE I',\L 175 It.8 4 t)

Executive5u rn mary Table2. chesapeakeBay watershed nitrogen, phosphorus and sedimentcap load allocations by jurisdiction.

NitrogeD Phosphorus Upland Sediment Cap Load Allocation Cap Lord Allocation CNp l,oad Allocation Jurisdiction/Basin (million pounds/year) (millionpounds/year) (milliotr tons/year)

PENNSYLVANIA Susquehanna 6't.58 1.90 0.'193 Potomac 4.O2 0.33 0.197 WestemShore 0.02 0,00 0.001 - 0.27 0.03 0.004 EastemShor€ MD 't PA Total 1.91) 2.26 0.995

MARYLAND Susquehanna 0.83 0.03 0.037 Patuxent 2.46 0.21 0.095 Potomac I t.8l 1.04 o.364 Westem Shore lt.27 0.84 0.100 EasternShore - MD 10.89 0.81 0.1l6 iVlD Total 3',1.25 2_92 0.112

VIRGINIA Potomac t2.84 L40 o.6t'1 Rappahannock 0.62 0.288 York 5.70 0.48 0.r03 James 26.40 3.41 o.925 EastemShore - MD 0.06 0.01 0.001 EastemShore - VA l.l6 0.08 0.008 VA lbtaL 51.40 6.00 1.9,1L

DISTRICT OF COLUMBIA Potomac 2.40 0.34 0.006 DC Total 2.40 0.14 0.{J06

NEWYORK Susquehanna 12.58 0,59 0.131 NY'tbtal 12.58 0.59 0.l3l

DELAWARE EastemShore - MD 2.88 0.30 o.o42 DETotal 2.88 0.10 0.042

WEST VIRGINIA Potomac 4.71 0.36 0.31l James 0.01 0.01 0.010 WV |-otal 4.',l5 o.31 0.320

SUBTOTAL r83 12.E 4.15 CLEAR SKIES RNDUCTION -8 B.\SINWIDE TOIAL 175 12.8 4.ls

Executive5u mmary Table3. ChesapeakeBay submerged aquatic vegetation (SAV) restorationgoal acreage by ChesapeakeBay Program (CBp) segment basedon the singlebest year of recordfrom | 930 to present.

CBP Segmgrt Nsme Segm€nt Northem ChesaoeakeBav CB ITF 12,90E

Upper CenrralCh€sapeake Bay C83MH Middle Cenral ChesapeakeBay CB4MH 2,51I Lower Ccntral ChesapcakeBay CB5MH 14.961 WestemLower ChesapeakeBay CB6PH 980 E^t"- Lo*ar i Mouth ofthe ChesapeakeBay CBSPH 6 BushRiver BSHOH 158

Middle River Back River BACOH PatapscoRive! PATMH

SevemRiver SEVMH SouthRiver SOUMH RhodeRiver RHDMH WestRiver WSTMH UpDerPatuxent River

Middle PatuxentRiver PAXOH Lowcr PatuxentRiver PAXMH 1,325 POTTF AnacosaiaRiver ANATF

Mattawoma. Creek MATTF Middle PotomacRiver POTOH 3.721 Lowcr PotomacRiver POTMH UpperRappahannock River RPPTF 20 Middle RappahannockRiver RPPOH O LowerRappahannock River RppMH 5.180 Corotoma[ River CRRMH 516 PiankatankRiver PIAMH 3,256

Lowcr MattaponiRiver MPNOH

PMKOH Middle York River YRKMH t76 Lower York River r5,096

FxecutiveSummary Table3. ChesapeakeBay submerged aquatic vegetation (SAV) restorationgoal acreageby ChesapeakeBay Program (CBP) segment basedon the singlebest year of recordfrom 1930to present(cont.).

CBP SegmentName S€gment Acreg Upper JamesRiver JMSTF 1,600 AppomattoxRiver APPTF 319 Middle JamcsRiver JMSOH ChickahominyRiver CHKOH Lower JamesRiver JMSMH JMSPH WestemBranch Elizabcth fuver WBEMH SouthemBranch Elizabeth River SBEMH EastemBranch Elizabeth River EBEMH Lafayette River LAFMH Mouth to mid-ElizabethRiver ELIPH LynnhavenRiver LYNPH NortheastRiver NORTF 88 C&D Canal C&DOH BohemiaRiver BOHOH Elk River ELKOH SassailasRivcr SASOH UDoerChcster River CHSTF Middl€ Ch€sterRiver CHSOH Lower ChesterRiver CHSMH EastemBay EASMH 6,108 Upper ChoptankRiver CHOTF 0 Middle ChootankRiver CHOOH bJ Lower ChoptankRiver CHOMH2 1,499 Mouth of the Choptankfuver CHOMHI 8,044 Little ChoptankRiver LCHMH 3,950 llonga River HNCMH 7,686 FSBMH 193 UpperNanticoke River NANTF 0 Middle NanticokeRiver NANOH Lower NanticokeRiver NANMH Wicomico River WICMH Manokin River MANMH 41tO

Upper Pocomoke River Middle PocomokeRiver POCOH Lower Pocomgke River POCMH 4,O92 TangierSound TANMH 37,965 lbtrl xcrcs I8.r.8rJ9

Exccutivc5u mrrary Table4. ChesapeakeBay submerged aquatic vegetation (SAV)restoration goal acreageby maior basin by jurisdiction.

Basio/Jurisdictlon SAVRestorationGoal{Acresl SUSQUEHANNA t2,856 EASTERN SHORE_ MD 76,t93 WESTERNSHORE _ MD 5,651 PATUXENT POTOMAC' MD 12,74'7 6,320 DC 384 RAPPAHANNOCK YORK JAMES EASTERNSHORE , VA 'I'O[AL 184.ri89 ' Brcokdownof PototrucSAV reriorationgouls byjurisdiciions are draft, pending confirmationofsplit b€twcenMaryland, Virginia and lhe Disidct ofCotumbia alongjurisdicliorsl lin€s. Duc to ongoingr€finement, some numbers in this table difTerfrom lhe Apiil 25, 2003 veBion jncludedin AppendixA aDdprevious model cstimatespresented in tabl€slIl-3 and lI-4.

Exccutive5|l mrnary cha pte.r | | Overviewof TechnicalTools

Pollutantloading allocationsmust be basedon credible science.It is impodant to understand and simulate the source loadings, as well as their impact on the water quality of the receiving water body. Because the ChesapeakeBay nutrient and sediment dynamics are so complex, establishing the scientific basis required the applicationof severalcoupled models of the ChesapeakeBay ecosystem: . The ChesapeakeBay Airshed Model provided simulationsof air sourcesof nutrients and air deposition onto the ChesapeakeBay watershed and the tidal surfacewaters; . The ChesapeakeBay WatershedModel tracked loadings from all sourcesof nutrients and sedimentsin the watershedand simulated pollutant transpod down to the ChesapeakeBay and its tidal tributaries;

. The ChesapeakeBay WaterQuality Model is an aggregateof severalmodels- hydrodynamic, water quality, hottom sediment, benthic community and SAV community which combined effectively, simulated the effects of nutrient and sedimentpollutant loadingson the water quality of the ChesapeakeBay and its tidal tributaries. A briefreview ol theseimportant tools is providedbelow. In addition,a description 'tiers', is provided of the developmentof managementcontrol scenarios,called which playeda critical role in the processof developingallocations,

TIERED MANAGEMENT IMPLEMENTATION SCENARIOS A seriesof watershedmodel scenarioswere designedto estimatethe nutrient and sedimentloads associated with increasedimplementation l€vels ofbest management practices(BMPs), wastewatertreatment upgrades and/or other point or non-point controltechnologies. The resultantwatershed model outputs-various combinations of nihogen, phosphorusand sedimentdelivered loads to tidal Bay waters-were usedas inputsto th€ ChesapeakeBay WaterQuality Model to evaluatethe relative responseof key tidal water quality parameters(i.e. dissolvedoxygen, water clarity and chlorophyll a concentrations)to thesewatershed loading levels. The rangeof

chapLer ii - Ovcrvrewof [r:chnrca]Tools water quality responses,in turn, helpeddefine cause(nutrient and sedimentloadings) and effect (tidal water quality) relationshipsand were used in assessing*re attainabilityof currentand refined designateduses (see TieredScenario Estimated Nutrient and SedimentLoads).

Thesetiered scenarios do not prescribecontrol measures necessary for the watershed jurisdictions to meet the Chesapeake2000 nntitenaand sedimentcap load allocations.Again, they were developedas a tool to assessrelative water quality impacts from a rangeof load reductions.The scenariosare theoreticalconstructs of iech- nologicallevels ofeffort anddo not representactual programs thatjurisdictions must implementor requiredcombinations of region-specificBMPs. Cost effectivecombi- nationsof BMPs will be evaluatedby the jurisdictions working directly with their tributarystrategy teams, who will addressreal issuessuch as physical limitations and any potentialadverse economic impacts from implementation.

The tieredscenarios characterize the ChesapeakeBay watershed,snutrient and sediment reductionpotential in terms of types of BMPs, extentof implementationand performanceof BMPs for both point and nonpointsources (Appendix B). Tier defi- nitionswere designed to ensureeach Tier went beyondthe nutrient and sediment load reductionsof the prwious tier and,therefore, irnply a'level of efiort'. The scenarios range from the Tier I scenario, representing extensions of cunent implementation ratesthroughout the watershedplus regulatoryrequirements in place by 2010, to everything, everyvhere by everybody (E3 scenario),which goesbeyond any previous 'limit ChesapeakeBay Programdefinition of oftechnology'(LOT). Two intermediate levelsof implementation,the Tier 2 and Tier 3 scenarios,were also developed. If the only objectiveofdeveloping the tier scenarioswas to relatetidal water quality responseto nutrientand sedimentload reductions,it would not hav€been necessary to define the scenariosin terms of increasedimpl€mentation levels of BMps and controltechnologies. This objectivecould havebeen accomplished by settingincre- mental loading reductions from all tributary basins in the Bay watemhed. However, assessmentsof attainability of the cuffent and refined tidal water designateduses required the associationof load reductionsto specific implementationlevels of BMPs or controltechnologies, their nutrientand sediment reduction efficiencies, and theirfeasibility of implementation.

Impoftant Note: Trersure artiJicial constructs oftechnological levels of efort and were not meant to representaclual programs thejwisdictions will eventu- ally implementto meet water quality standards.tn addition, the tiers do not denote combinations of region-specilic BMPs that would besl reach the nitrogen, phosphorus and sediment cap loads allocated to each juisdiction within each tributary- They were developeclas an assessmenttool to determine relative wster quality impactsJiom a range of load reductions. Tier deJinilions were designedto ensure each ner went bqtond the nutrient and sediment load reductions of the previous Tier

Appendix A of the kchnical Support Document describesthe developmentof the tier scenariosand the pollutant control technologiesrepresented in each tier (U.S. EPA 2003a).Both Appendix A and ChapterV of this documentpresent the

(:h;r pter ii - Overvir.woi lcchnicalToois ChesapeakeBay watershed model estimates of the nitrogen, phosphorusand sed.i- ment load reductionsassociated with eachofthe tier scenarios. The tier scenarioswere basedprimarily on BMPs and control technologiesdirected towardreductions in nitrogenand phosphorusloads. The model-simulatedsediment reductions were incidental responsesto the implementation of nutrient reduction BMPs. Other sedimentreduction management practices are availableand may, if implementedalong with nutrient reductionefforts, afford additionalwater quality improvements(see Chapter III). This is especiallytrue for BMPs appliedin the near shoreareas of the tidal Bay.

DEVELOPMENTOF THE TIERED SCENARIOS 'source'work- The tiered BMP implementationlevels werc initially definedby the groups of the ChesapeakeBay Program Nutrient Subcommittee-The Agricultural Nutrient Reduction, Forestry, Point Source and Urban Stormwater workgroups, which is comprisedofrepresentatives ofBay watershedjurisdictions and othertech- 'source'. nical experts,contributed expertise and information for their assigned In some cases,the Nutrient Subcomrnittee'sTributary Strategy Workgroup edited the tier scenario definitions so that necessary input decks for the watershed rnodel, which capturedthe essenceof the definitions,could be developed.

Projected201 0 Conditions All tier scenarioswere basedon 2010 projectionsofland uses,human populations, agriculturalanimal populations,point sourceflows, and septicsystems, as well as 200712010or 2020 air emissions.Land use and human and animal population projectionswere developedfrom an array of national,regional, and statedatabases as describedin ChesapeakeBay WatershedModel Lqnd Useand Model Linkryes to the Airshedand EstuarineModels (Hopkins et al. 2000). Agricultural land uses were projected from agriculhral censuscounty information (1982, 1987,1992 and 1997)according to methodologieschosen by individualstates. The projected animal populations were also based on county agricultural census trends and information proyided by state envfuonmentaland agricultural agencies. Urban land uses for 2010 were projectedfrom a methodologyinvolving humal populationchanges, as determined by the U.S. CensusBureau for 1990and 2000,as well as by someindividual stateagencies. The populationchanges were relatedto 1990 high-resolutionsatellite imagery ofthe ChesapeakeBay watersfied,which is the root sourceof urban and forest land acreages.In the caseof Maryland, urban growth from 2000 to 2010 was deierminedby Maryland Departmentof Natural Resourcesand Maryland Departmentof Planning. With urbanand agricultural land use acreages fixed for 2010,the remainingland was divided betweenforest and mixed open in the sameproportion that existedin 1990 for New York, Pennsylvania,Delaware, West Virginia, andthe District of Columbia. The 2010 forestacreage was fixed for Maryland andVirginia following methodologies or datasubmitted by thosestates with the remainingacreage being mixed open.

ch.rpter ii . Overviewof TechnicalTools Tier Scenario Components Point Source

A multi-stakeholderNutrient Reduction Technology Cost Task Force, which consistedof federal,state and local representativesas well as municipal authority representativesand expertconsultants, was formed as a temporaryextension of the Nutrient Subcommittee'sPoint SourceWorkgroup. The Task Force defined what would be logical tiers (breakpoints) for incrementallevels of point sourcecontrol technologyimplementation (U.S. EPA 2002). Using wastewaierflows projectedfor the year 2010,the tier scenariosrange frorn the current(year 2000)treatment levels to the E3 scenario.

Futureflow projectionswere developedeither from populationprojections or information obtained directly from the municipal facility operators.The tier and E3 scenarioflows for industrialdischargers remained at 2000 levelsbecause these flows arenot necessarilysubject to populationgrowth. The point sourcefacilities analyzed in this effort include all signifrcant facilities (including indusrial) as defined by New York, Pennsylvania,Marytand, Virginia, Delaware,West Vrginia and the District of Columbia.

Nonpoint Source:Agriculture

In the Tier I scenario,nonpoint source agricultural BMP implementationrates between1997 and 2000 were continuedto the year 2010 with certainlimitations. Since historic BMP data were not available lrom New York, Delawareand West Virginia, 2010 Tier I projectionswere determinedfrom watershed-wideimplementation rates from statesthat employed and tracked similar practicesfrom 1997 through2000.

The Tier 2 and Tier 3 scenarioBMP implementationlevels were generallydetermined by increasingBMP implementationby a fixed percentageof the rernaining acreagebetween Tier I and E3 levels.The percentageswere specifrcfor eachBMp and appliedwatershed-wide.

Nonpoint Source:Urban

The Tier I scenario representsvoluntary and regulatory stofm water management programsthat are or will be in placeby 2010.These include both federalprograms, such as the EP.{s National PollutantDischarge Elimination SystemPhase I and II storm water regulations, and state erosion control/stom water management programs.The Tier 2 and 3 scenariosrepresent progressively increasing levels of urbannonpoint source BMP implementationbeyond Tier l.

Atmospheric Deposition

The ChesapeakeBay Programmodeled four different nitrogenoxide (NOj emission reductionscenarios to estimatechanges in atmosphericnitrate deposition and loading to the ChesapeakeBay watershed(U.S. EPA 2003a):The NOy emission reductionsassociated with Tier I and 2 scenariosare based on Clean Air Act regulations.In the Tier 3 and E3 scenarios,NOx emissionreductions go beyond currentregulations and include aggressivevoluntary controls. All scenariosinvolve chr p ler ii - O'c,y,6', o1 f r hnrr,rl OOs the combinedNOx emissionreductions from 37 stateswithin the ChesapeakeBay airshed,well beyondthe ChesapeakeBay watershedjurisdictions' boundaries.

E3 Scenario To estimatenon-attainment caused by human-causedconditions that cannot be remedied,a boundaryscenario had to be defined.In the past,the ChesapeakeBay Program partnersdefined this as the 'limit of technology'. The BMP levels and controltechnologies in the E3 scenarioare believed by the ChesapeakeBay Program partners to be beyond feasible. Cosr, physical limitations and sociaUeconomic impacts were not takefi into accountin order to eliminate subjectivityas much as possiblefrom the E3 definitions. The E3 scenariorepresents rhe maximum theoreticalimplementation of the besl combinationof BMPs or control technologiesavailable to a land useor situation.It is assumedthat nutrient and sediment reductions beyond this level represent "human-causedconditions that cannotbe remedied."Cenerally, these are the best nutrient and sedimentreductions possible with current technologiesat maximum BMP implementationlevels and include new technologiesand managementpruc- tices that are not currently part of jurisdictioral pollutant control stmtegiesor federal, stateor local cost-shareprograms. Appendix A of the TechnicalSupport Documentdetails the assumptionsand methodologiesused to developeach control technologyand BMP-basedimplementation level in the E3 scenariofor all nutrient and sedimentsource categories and land uses(U.S. EPA 2003a).

TIEREDSCENARIO ESTIMATED NUTRIENT AND SEDIMENTLOADS The estimatedWatershed Model loadsfor nitrogen,phosphorus and sedimentloads from simulatedimplementation of the tiered and E3 scenariosare describedbelow and graphicallysummarized in figuresII-1, II-2 and II-3, respectively. Theseload estimates are compared with modeled2000 Progressloads of285 million poundsof nitrogen per year, 19 million poundsof phosphorusper year, and 5.04 million tons per year of land-basedsediment.

Tier 1 The nutrientand sedimentloads associated with the Tier I scenarioare 261 million poundsof nitrogenper year, 19.1million poundsof phosphorusper year' and4.64 million tons of land-basedsediment per year.This rqrresentsan 8 percentreduction in nitrogen,a I percentreduction in phosphorus,and an 8 percentreduction in sediment loadsto the ChesapeakeBay from 2000 progresslevels.

Tier2 The nutrientand sedimentloads associated with the Tier 2 scenarioare 221 million pounds of nitrogen per year, 16.4 million pounds of phosphorusper yeat, and 4.14 million tons of land-basedsediment per year. Comparedto 2000 progress estimatedloads, this repr€sentsa 22 percent reduction in nitrogen, a 14 percent reductionin phosphorus,and an 18 percentreduction in sedimentloads.

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Figure ll-1 . Nitrogenloads delivered to the ChesapeakeBay and its tidaltributaries under the watershedmodel-simulated 2000 Progress,tiered and E3 scenarios. SourceiChesapeake Bay Progaam website http/ vww(hesapeakebay.net.

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Figure ll:2. Phosphorusloads delivered to the chesapeakeBay and itstidal tributariesunder the Watershedmodelsimulated 2000 Progress,tiered and E3 scenarios, Source:Chesapeake Bay Program website http:/,vww.chesapeakebay.net.

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Figure ll-3. Land-basedsediment loads delivered to the ChesapeakeBay and itstidal tributaries under the water5hedmodel-simulated 2000 Progress,tiered and E3 5cenarios. SourceiChesapeake Bay Program website http:/Arww.(hesapeakebay.net.

Tier 3 The nutrientand sedimentloads associated with the Tier 3 scenarioare l8l million pounds of nitrogen per year, 13.4 million pounds of phosphorusper year, and 3.62 million tons of land-basedsediment per year. This representsa 37 percent reductionin nitrogen,a 30 percentreduction in phosphorus,and a 28 percentreduction in sedimentloads from 2000 levels.

E3 The combinationofaggressive land and air nutrientcontrols resulted in E3 scenario loadsofabout I 16 million poundsofnitrogen per year, l0.l million poundsofphos- phorusper year,and 2.95 million tonsofland-based sediment per year.Compared to 2000progress loads, this representsa 59 percentreduction in nitrogen,a 47 percent reductionin phosphorus,and a 4l percentreduction in land-basedsediment loads.

CHESAPEAKEBAY PROGR^AM ENVIRONMENTALMODELS The ChesapeakeBay Programpartners use a seriesof environmentalmodels to project changesin the complex Bay ecosystemdue to managementactions. The ChesapeakeBay Programhas developedwhat have becomestandard large watershed estuarine modeling tools, including an airshed model or Regional Acid DepositionModel (RADM) (Shin and Carmichael1992; Appleton 1995, 1996),a watershedmodel (Donigian et al. 1994;Linker 1996;Linker et al. 2000), an estuarine hydrodynamicmodel (Wang and Johnson2000), an estuarinewater quality

ch.rptcr ii - Over,/ic\,vof lechncal fools model (Cerco and Cole 1993, 1995a, 1995b; Thomann et al. 1994; Cerco and Meyers 2000; Cerco 2000; Cerco and Moore 2001; Cerco et al. 2002a),and an estuarinesediment diagenesis model (Di Toro and Fitzpatrick 2001). The Chesa- peakeBay Programhas used these environrnental models for morethan l8 yearsand has refined and upgradedeach of the modelsseveral times. Figure II4 portraysthe interconnectionsamong these cross-media models. Resultsfrom the integratedairshed, watershed and estuarinemodels are used to elucidatecomplexities like eutrophicationof the ChesapeakeBay or to closely examine sediment soufces to assesstheir impacts on water quality and living resourcesin tidal waters.Together, these linked simulationsprovide a syst€mto estimatedissolved oxygen, water clarity and chlorophyll a conditionsin 35 major segmentsof the ChesapeakeBay and its tidal tributaries. The same criteria attainmentassessment process applied to observeddata is applied to integrated 'scenario' modelingimonitoring data to determinelikely criteria attainmentunder managementloading scenarios(U.S. EPA 2003b,Linker et al. 2002). Th€ watershedand airshedmodels are loading models.As such,they provide estimates of the impacts of manag€ment actions through air emission controls, agricultural and urban best-managementpractices, and point sourcetechnologies

Figuae ll-4. Cross-mediamodels of the ChesapeakeBay airshed, watershed and e5tuary. Source:Chesapeake 8ay Program website http://www.chesapeakebay.net.

.tr.rpte r ii . Ovl'rvicwol Tcchnicalloo ls that will reducenutrient or sedimentloads to the ChesapeakeBay tidal waters.The advantageof using loading models is that the full simulation through different hydrologyperiods (i.e., wet, dry and average)can be simulatedon existingor hypo- theticalland use pattems.All of the ChesapeakeBay Programmodels used in this systemsimulate the samel0-year period from 1985to 1994(Linker et al. 2000). The models are linked together so that the output of one simulation provides input data for anothermodel. For example,the nitrogenoutput from RADM affectsthe nitrogeninput from atmosphericdeposition to the WatershedModel. The Watershed Model, in turn, transportsthe total nutrientand sedimentloads, including the contributionsfrom atmosphericdeposition, to the ChesapeakeBay and its tidal tributaries throughthe boundaryof the watershedand estuarinedomains. The WaterQuality Model examinesthe effcctsof the loadsgenerated by the WatershedModel, as well as the effects of direct atmosphericdeposition, on Bay water quality and living resources. The modelsused by the ChesapeakeBay Programfocus on quantifiableoutcomes, suchas reductions in estimatednutrient and sedimentloads resulting from integrated point source,nonpoint sourceand air emissionmanagement actions, rather than a pollutant reduction strategy based on a single medium. For ChesapeakeBay Programdecision-makers, model resultsare optionsto be examined,analyzed and furtherdeveloped through an iterativeprocess with the modelpractitioners. This was the processinvolved in determiningcap load allocations(see section above titled TieredManagement Implementation Scenarios). The modelsproduce estimates, not perfectforecasts. Hence, they reduce,but do not elirninate,uncertainty in environmentaldecision making. Used properly, the models assistin developingnutrient and sedimentreductions that aremost protectiveof the environment,while being equitableand achievable.

CHE5APEAKEBAY,AIRSHED MODEL AND AIMOSPHERICDEPOSITION RegionalAcid DepositionModel The RegionalAcid DepositionModel, or RADM, is designedto provide estimates ofatmosphericnitrogen deposition resulting from changesin precursorair emissions due to managementactions or growth, and to predict the influenceof sourceloads from one region on depositionin other regions(Chang et al. 1987).The current versionof RADM, RADM 2.61, encompassesa geographicdomain of 2,800 kilo- metersby 3,040 kilometers (Dennis 1996). Longitudinal coveragein the €astem United Statesis centralTexas to Bermudawhile latitudinal coverageis fiom south ofJames Bay, Canadato Florida, inclusive(Figure lI-5). Grid cells are 80 kilometer by 80 kilometerwith 15 vertically layeredcells placedfrom ground level to the top ofthe troposphere,which equalsan altitudeof 16 kilometers.The total numberof cells in the model domain is 19,950(Chang et al. 1990).As shown in Figure II-5, over the regionsof the mid-Atlantic statesand the ChesapeakeBay watershed,the RADM containsa finer grid of 20 kilometer by 20 kilomeier cells nestedinto the largergrid, allowing liner spatialdistribution ofnitrogen deposition.

chirpter ii - Overvicwr.)f fe'chnical lools FigurelF5. RegionalAcid Deposition Model domain grid and fine-scale nested grid for the ChesapeakeBay waterrhed. Source:Dennis 1996.

The RADM hasbeen used to estimatethe areawhere nitrogen emission sources have the greatestpotential in depositingnitrogen, both wet and dry, to a watershed.The .principal areaencompassing these sources is referredto as the airshed'.Figure II-6 shows the boundariesof the ChesapeakeBay watershedjuxtaposed with the principle airshedsfor both reduced(ammonia) and oxidized (NOx) nitrogen.The ChesapeakeBay's ammoniaairshed is about 688,000 squarekilometers (266,000 squaremiles) in size.This is four times largerthan the ChesapeakeBay's watershed andtwo-thirds the sizeofthe NO1 airshedwhich is 418,000square miles (1,091,600 squarekilometers) (Paerl et al. 2002).

Airshedsare not as lirmly definedas watersheds in that thereare no clearboundaries to the llow of chemicalsin the atmosphereas thereare for the flow of surfaceand groundwaters in watersheds.The absoluteinfluence that an emissionsource has on depositionto an areacontinuously diminishes with distance.Operationally, modelers

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Figure ll-6. Principlenitrogen airsheds lor the ChesapeakeBay and itswatershed. Sour(e:Chesapeake Bay Program websile htlp//www.chesapeakebay.nevwq

have found that a good distanceof demarcationfor settidgthe airshedboundary is the 65 percentcontour of the normalizedrange of influenceof a sourceregion. It is impofiant to understandthis concept of airshedsbecause the relationships betweenemissions and deposition,and subsequentlyatmospheric loadings into a waterbody, are not equal.For example,if 100pounds ofnitrogen werereleased into the air from a source,it will not all be depositedat oncenor in one area.The annual depositionwill be distributedover spaceand will be unevenlydistributed in time. Just as emissionsand depositionare not in a 1:l ratio, neither are depositionand loadingsto a waterbody. The terestrial landscapewill retainmuch ofthe deposited

ctra[)te. ii . Overvicwof Tr:<-hnrcalTools nitrogen.For example,current belief is that approximatelyl0 percentof nitrogen depositedto a typical forestecosystem will be transportedinto receivingwaters. The three-dimensionalRADM solves a series of conservationequations and considersa complexrange ofphysical and chemicalprocesses and their interactions. It is an Eulerian model in which the concentrationsof gaseousand particulate speciesare calculatedfor the specificgrid cells as a function of time. The calcula_ tion dependson emission input rates, as well as three-dimensionaladvective lransport,dry depositionrates, turbulent transport, chemical transformations, scav_ engingand precipitation.

Meteorologicalfields used for advectivetransport and meteorologicalconditions for RADM chemistryare from the PennsylvaniaState University National Centerfor AtmosphericResearch Mesoscale Model (MM4). The MM4 is a weathermodel used to recreatedetailed meteorology (Dennis et al. 1990;Brook et al. 1995a,b). The chemistrythat is simulatedby the model consistsof 140 reactionsamong 60 species.Photolysis and oxidant photochemistryis includedin the simulationas are aqueousphase reactions which occur in clouds.Forty-one of the longerJivedchem_ ical speciesare transportedbetween model cells.

The key nitrogenspecies that are simulatedand areofconcem to coastalwatersheds are: l) particulatenitrate (pNO3-),nitdc acid gas (HNO3) and nirate (NO3) in precipitation,which all originate from NOx emissions;2) particulateammonium (NHa+),ammonia gas (NH3) and ammonium in precipitation,which all originate from ammoniaemissions; and 3) dissolvedorganic nitrogen (DON). Although the sourcesof DON are not well identified,it is believedto be a small fractionof the total nitrogend€position.

The itrogen oxide ernissionsthat are accountedfor in the RADM include those from anthropogenicfuel combustion,soil biological processesand ammonia.These emissionsare input to the completelymixed grid cells of the model on an hourly time step.The simulationuses dynamically determinedtime stepsof secondsto minutesto generatemodel outputof wet and dry depositionon an hourly basisfor eachsurface cell.

Determinationof AtmosphericFlux

While the RADM providesestimates of atmosphericdeposition due to growth or managementof atmosphericemissions, a basedata set of atmosphericdeposition is neededto provide a continuousl0-year time seriesof daily atmosphericdeposition loadsto the watershedand estuarymodels. This basecondition of depositionestab_ lishes a referenceto which other atmosphericdeposition reduction scenariosare compared,quantifying the effectsof managedreductions in emissions.The reduction scenariosare rooted in RADM results, representchanging levels of both regulatory and voluntary controls, and are simulated liom utilitv, industrial and mobilesources,

Sinceprecipitation is theprimary forcing functionin the ChesapeakeBay Watershed Model, greatcare is taken in dweloping the time-variableatrnospheric flux. A data

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7 set of wet depositionof nitrateand ammoniais formed throughconcentration data from a regressionmodel and precipitation data from gauging stations that are weightedaccording to a Thiessenpolygon method. The regressionmodel uses National Atmospheric Deposition Program,National Trends Network data from monitoring stations in the Chesapeakewaiershed area to determinewet inorganicnitrogen concentrations. The regressioncalculates concentrations ftom measuredprecipitation amounts, the month of the year, and latitude. The concentationsare then appliedto the volume of precipitation,for eachmodel segment,to establishdaily depositionofwet nitrate, ammonia,and organic nitrogen for the l0-year simulationperiod ofthe WatershedModel. A rate ofdry deposition of nitrateis determinedfor eachmodel segmentfrom averageproportions of wet-to- dry depositioncalculated by RADM. When usedfor scenariosthat havereduced emissions and subsequentdeposition in the Chesapeakewatenhed, RADM informationon nitrogen emissionreductions is appliedto the WatershedModel througha proportioningmethod. It is assumedthat the RADM referenceinputs are the sameas the calculatedatmospheric flux. Frac- tional changesto the ITADM referencedeposition are related to the deposition databasefor eachchemical species and both spatiallyand temporally.The resultsare revisedfluxes to the watershed,tidal waters and their respectivemodels that are used,in part, to determinethe effectsof emissioncontrols on nutrient loads,water quality and living resources.

CHESAPEAKEBAY WATERSHED MODEL The ChesapeakeBay WatershedModel estimatesthe delivery of nutrientsand sedi- m€nt from all areas of the watershed to tidal waters under different management scenarios(Donigian et al. 1994;Linker et al. 1996; Linker 1996).The continuous, deterministicmodel has been in operationat the ChesapeakeBay Programsince 1982.Since that time, many refinementsto the simulation and dataused in it havii beenmade. Phase 4.3 of the WatershedModel, in conjunctionwith the airshedanti estuarinemodels, was employedin the developmentof the nutrientand sediment cap load allocations. The ChesapeakeBay Program'sWatershed Model is basedon a slightly modified versionof Hydrologic SimulationProgram-Fortran (HSPF) releaseI I (Bicknell et al.1996),a widely usedpublic domainmodel supportedby the U,S. Environmental ProtectionAgency, U.S. GeologicalSurvey, and U.S. Army CorpsofEngineers. The systemis run on personalcomputers with the Linux operatingsystem. All supporting programsas well as HSPF areopen sourceand written primarily in Fortran77. Nutrient simulationmodules in the WatershedModel are detailedand flexible, and thus can be usedto simulatea varietyof land use types with associatedapplications of chemicalfertilizers and animal manure.The model also takesinto accountloads from point sources,atrnospheric deposition and onsite wastewatermanagement systems.In addition,the simulationconsiders nutrient and sedimentreductions due to BMP implementationas well as attenuationof chemical speciesas they havel through the river reachesto tidal waters of the ChesapeakeBay. The Watershed

chap|er ii . C'/eruiewof icchnical-rools Model simulatesa period of ten years (1985-1994)on a one-hourtime step and resultsare aggregaredinto daily loadsand flows, to be usedas input to the estuary model or into reportedl0-year averageloads lor comparisonamong scenirnos.

WatershedModel Segmentation

To simulatethe deliveryofnutrients andsediment to the ChesapeakeBay, the 64,000 squarernile ChesapeakeBay watershedis divided into 94 majcr hydrologic model segmentsthat havean averagesegment area of 680 squaremiles (177,000hecfares) (Figure II-7). At the interfaceof the WatershedModel and Water Quality Model domains,below-fall-line model segmentsare further divided into sub-segmentsto deliver flow and nutrientand sedimentloads to appropriat€areas of the tidal waters (Hopkinset al. 2000).

Segmentationpartitions the watershedinto regionsof similar characteristicsbased on criteria suchas topographicareas with similar soil characteristicsand slopes.or

MeJorTrlbularlaa ol fi. CtoaaFsk. Bary I elstenlslon: ulavuro I el stenl sxonevraontl I J MEsAtvEa BAsrN I ltturerr av:n aesn ! aorourc nrvenersrn RApPAHANNoCK =l RtvER BASIN ffi susouettlttnntvenarenr f westeatsnonevlnvL,ltto I vonx nrvenersrr,r

Figure ll-7. ChesapeakeBay Watershed Model segmentation and majortributary basins. Source:lanker et al. 2000,

r h.rptcr ii - Ovcrvrcwr:f Tcchnic.rlTools similar travel times in river reaches(Hartigan 1983). Another considerationin defining model segmentsis the locationof reservoirsor monitoringstations. Model segmentsare localedso that segmentoutlets are as close as possibleto monitoring stationsthat collect water quality and dischargedata (Langland et al. 1995).

The proximity of monitoring stationsto the outlet of model s€gmentsis important becausethe model is calibratedat the segmentlevel. It is imperativeto havethe most accuratecalibration of nutrient and total suspendedsediment concentrations and flows in the river reachesso that the output loadsof one segmentaccurately input the adjacentdownstream segment

Overall,the right sizefor segmentationweighs two factors.Ifa segmentis too large, meaningful differences of many of the simulation paramet€rs are missed. If a segmentis too small,it could be difficult to acquireall the datafor the simulationat that level, or the computingcapacity of the model could be limited.

WatershedModel Calibration The ChesapeakeBay Programcalibrates the Watershed Model overall availabledata and then usesthe calibratedmodel to test managementscenarios. In the Phase4.3 version of the model, flow and water quality data from 1984-1997were used for calibration.The calibrationwas reviewedand approved by ChesapeakeBay Program Modeling Subcommittee.The subcommitteemembers and quartedy review par- ticipants are recognized academic experts in the field of modeling and representativesfrom all ChesapeakeBay Agreement signatory jurisdictions- Pennsylvania,Maryland, Virginia and the District of Columbia. For the calibrationof land uses,simulated exports from land usesare comparedto literaturevalues and an analysisof the inputs.For example,the calibrationof ctop- land considersthe growth and nutrient uptakeof estimatedcrop types taking into accountdrought, heat stress,and the growing season- as well as considerationsof the estimatednutrient inputs. The simulatedcropland exports are, in tum, compared to export valuespublished in peer-reviewedscientific literature and relevantmodel parametersare adjusted,if necessary,to achievethe bestmatch. For the calibrationof river reaches,simulated results for streamflows, nutrientand sedimentconcentrations and loads, as well as other water quality parameters,are compared to observed data from in-stream monitoring sites. Results for the .hydrology calibration of the Phase4.3 WatershedModel can be found on the ChesapeakeBay ProgramWeb site at http://wwwchesapeakebay.net/pubs/ll3.pdf while water quality calibration information can be accessedat: http://www. chesapeakebay.net/pubs/23 8.pdf. Calibrationresults are presentedas plots and statisticaltables ofmodel information and monitoring data from calibration stationsfor the following parameters:flow, temperature,dissolved oxygen, total suspendedsediment, total phosphorus,organic and particulatephosphorus, phosphate, total nitrogen, nitrate, total ammoniaand organicnitrogen.

ch.rpter ii . Ov*r',/lewof lechnicllTo(]1! WatershedModel Data Sources

Sinceprecipitation, in a largepart, drives loads to the tidal Bay water,much effort is spentdeveloping this database. For the l0-year simulationperiod of the watershed Model, rainfall data from 147 monitoring stationsare used. Typically, about six stationsare usedto developthe precipitationrecord for a model segmentrhrough a Thiessenpolygon method for spatial distribution. In addition, temperature,solar radiation,wind speed,snow pack and dew-pointtemperature data are collgctedfor the simulation from sevenprimary meteorologicalstations in the watershed(Wang et al. 1997).

A consistentland use datasetis compiled for the €ntire Chesapeakebasin using a LANSAT-derivedGIS land cover as a base (U.S. EpA 1994). The land covei is enhancedwith detailedinformation on agriculturallands at the county level from the U.S. CensusBureau series, Census of Agriculture for 19g2, lgg7,lgg} and 1997 (Volume l, GeographicArea Series).County tillage information is acquiredfor the conventionaland conservationcropland distribution from the conservationTech- nology Information Center (palace et al. l99g). The land or sourc€ catesones simulatedin the WatershedModel are as follows: . Conventional-tilledcropland; . Conservation-tilledcropland; . Croplandin hay; . Pasture;

. Animalwaste areas; . Forest;

. Perviousurban; . Imperviousurban land; . Non-agriculturalherbaceous or mixed_openland; and . Atmosphericdeposition directly to water surfaces.

Calculationsand allocationsof the agricultural land categoriesfollow methods describedin c'lresapeake Bay watershedMocrer Land use ani Moder Linkages to the Airshedand EstuarineModels (Hopkins et al. 2000).The non_agriculturalland use classificationsof 'forest', ,pervious'and.impervious .mixed_open, 'water'are urban', and generallydeveloped through comparisons ofthe agriculturalland u"."ug" and the GIS land coverdatabase and projectionsor interpolationsofthese. Hopkins et al. (2000) describesthese calculations and alloc,ationsin detail. For crop land, stateagricultural engineers provide chemical fertilizer and manure applicationrates and timing of applicationsas well as informationon crop rotations and.the.timing of field operations.The information on manure applicationsto cropland is part of a time-varying mass balanceof manure nutrients develoned through the Agricultural Census, animal populations and predominant manure handlingpractices (Palace et al. 1998).

. lr.rf)tcr ii . Ovr:rvicr,vr:f fr:chnir:al fcols Soil characteristicsfor bothnutrient interactions and hydrology are obtained fiom the Soil ConsewationSewice Soil InterpretationRecords (USDA 1984)with information on soil typesand land slopefrom the NationalResources Instihrte (NRl)' Deliveryof sedimentfrom eachland use is calibratedto the NRI estimatesofannual edge-of-field sedimentloads calculated by the UniversalSoil Loss EqLration(USLE). 'manure For animal wasteareas, the designationofa acre'allows for the simulation of high nutrient contentrunoff from animal operations'Manure acres are basedon the populationof different animal types in the watershedas given in Agricultural Ccnsusdata. The animal types includebeef and dairy cattle,swine and threecate- gories of poultry (layers,broilers and turkeys).Nutrient export from animal waste storageareas is simulatedas a concentrationapplied to the calculatedrunoff where the surfacearea of animalwaste storages, ot manureacres, changes with the number of animalsand implementationof animalwaste management systems. Loadsfrom point sources,combined sewer overflows (CSOs), and septicsystems are input directly to river reaches-Point sourceinputs from municipal and industrial soutcesare developedfrom stateNational Pollution DischargeElimination System (NPDES) records.If no state NPDES data are available,state and year-specific defaultdata are calculated for eachmissing parameter and annualestimates ofloads are basedon tlow from the wastewatertreatment plant. Severalcities in the watershedhave a sewersystem with CSOs' including Wash- ington, D.C., Richmond,Virginia and Harrisburg,Pennsylvania. Estimates of the averageannual discharge from CSOsare only availablefor Washington,D.C andthe annualdischarge is evenlydistributed over the simulationperiod of the model. Loads from septic systemsare calculatedusing U.S. CensusBureau dataof waste disposalsystems associated with households,along with a methodologysuggested in Maizel et al. (t995) where standardengineering assumptions of per capita nitrogenwaste and attenuation ofnitrogen areapplied. Septic system loads are simulatedas nitrateloads discharged to the river reaches.

WatershedModel Simulation Each WatershedModel segmentcontains information generatedby a hydrologic sub-model,a nonpoint sourcesub-model, and a river or transportsub-model. The hydrologicsub-model uses rainfall, evaporationand meteorological data to calculate runoff and subsurfaceflow for land usesin eachmodel segment. The surfaceand subsurfaceflows ultiinately drive the nonpoint sourcesub-model, which simulatessoil erosionand pollutant loads frorn the land to the riversusing, in part,input datafor atmosphericdeposition, land useareas, nutrient applications, and BMP implementationand reductionefliciencies. A river sub-modelroutes flow and associatedpollutant loadsfrom the land throughlakes, rivers and reservoirsto the ChesapeakeBay. For nitrogenand phosphorus,the simulationrepresents a massbalance in the basin, so that the ultimatefate ofthe input nutrientsis l) incorporationinto ctops,forests, or other vegetation,2) incorporationinto soil, or 3) loss through river runoff or

r-h.rptcr ii . Ovcr,rlt:wof feclrnicallools discharge directly to the ChesapeakeBay. Fate of nitrogen may also include volatilizationto the atmosphereand denitrification Much ofthe nutrientsimulation for perviouslands considers cycling and storagesin the soil plant and massas well as movementbetween the storages,fhereby making these land use simulations sensitive to nutrient inputs. Crops are specifically modeled through a yield-basednutrient uptake algorithm allowing for the direct slmulation nutrient of managementpractices since exports rely heavily on the nutrientlevels abovecrop need..Nutrientexports fiom imperviousurban land depend on storage, which accumulatesby a factorequal to atmosphericdeposition. Rainfall washesoff this storage and the intensity oi the rainfali determineshow much is washedoff. Sedimentis modeledas erodedmaterial washedoff perviousland surface,eroded from stream banks and transportedto the tidal Bay waters. This simulatiorLis performedthrough a module,which representssediment export as a functionofthe amountof detachedsediment and the runoff intensity. The lumped-parameter HSPFmodel simulateseach land use as an averagefor the entirc segment.For example, conventionally_tilledcropland i. _oa"fla u. un averagecrop rotation of corn, soybeans,and small grains in a segmentwrth an averagemodel-segment input of chemical fertilizer and manure loads, and with averageslope, soil conditions,and nutrient cycling characteristics.The simulated single-acreland use, in tum, is multiplied Uy the acresof eachland use draining to eachriver segment. EachWatershed Model river reachis simulatedas completelymixed waterswith all land usesconsidered in direct hydrorogiccontact. of'the 4i reachesmodered, the averagelength is 106miles ( 170kilometers), the averagedrainage area is 730 square miles ( 1,900square kilometers),and the averagetime-of travel is one day. Sevenof the reachesare impoundedby reservoirsand are simulatedas such. The riverine simulation includes HSpF modules that consider,in part, sediment transport,oxygen transformations, ammonification,nitriflcation, and modeling of periphytonand phytoplankton. For areasclose to the ChesapeakeBay and its ticlal tributarieswith a time of travel lessthan one day, a river reachis noi modeledand tenestrial nutrientand sedimentloads are directly loadedto the tidal estuary. For all nutrientand sediment reductionscenarios, the Watershed Model is run for a l0_ yearhydrologic period, representingl9g5 to 1994,inclusive. This time rlamematches the yearssimulated in the ChesapeakeBay EstuaryModel and providesa consistent l0-year hydrology, incrudingwet, dry, andaverageperiods offlow in eachbasin. Nutrient and sedimentloads from the WatershedModel are reportedas the average annual load over this l0-year period to make comparisonsamong model scenarios without the influence of variable hydrology on loads. For example, any 2010 scenariohas land uses,human and animal populations,point sourcedischarges, and Iandmanagement projectedto the year20lb but modelei usingthe same rgs5_lgg4 hydrology used for arl other watershedModel scenarios.A"ssessing roads for an average-hydrologyyear showshow anthropogenicfactors, such as changesin land use_andmanagement practice implementation,change average annual nutrient and sedimentloads to the ChesapeakeBay over decadalJeriods o*f ttme. chi:lF)t(-,r ii . Ovr:r'lc'rlof fechncal l-ools CHESAPEAKEBAY WATERQUALITY MODEL the The ChesapeakeBay Water Quality Model used to assist in developing hydrody- Chesapeaki2000 nuirient and sedimentcap load allocationsis a linked processes'benthic namic and water quality model which is coupledto a sediment Chesa- infaunal communiiy and submergedaquatic vegetation (SAV) model' The 'third major peake Bay water quality model is a generation' model with two the original i"fin"-"ni, since its debut in 1992 when it was first used to develop ir| Agreement nutrientcap load allocationscommitted to rhe 1987Chesapeake Bay 1993; (ChesapeakeExecutive Council 1987;Thomann et al' 1994;Cerco and Cole Virginia C"."o ol. 2002a,2002b). In 1998,the modelgrid was refinedin the lower "t infauna tidal tributariesand lower ChesapeakeBay mainstemwith the new benthic tributaries and SAV model. In 2002,the upperChesapeake Bay mainstemand tidal of grid was rehned along with signiticantenhancements in the model simulation During the 2002 model refinements' irimary productivity (Cerco et al. 2002a). oxygen' particuiaiemphasis was placedon the calibrationand analysisof dissolved sediment,water clarity, SAV and chlorophyll a.

HYDRODYNAMIC MODEL in 3 The ChesapeakeBay Hydrodynamic'or CH3D (Curvilinear Hydrodynamics mate- Dimensionsl,Model providesadvective transport for dissolvedand particulate covers the entire rial simulated in the Water Quality Model The model grid l3'000 ChesapeakeBay, tidal tributariesand the adjacentocean boundary with about computationmodel cells. y the density The complexmovement ofwater within the ChesapeakeBay' particula Bay tlriven vertical estuarine stratification, is simulated with a chesapeake Three- hydrodynamicmodel of more than 13,000cells (Wang and Johnson2000) of dimenslonalequations of the intertidal physical system, including equations provide the continuity,momentum, salt balanceand hcat balance,are employedto waterquality correctsimulation ofthe movement,or the baniels to movement,ofthe formula- constituentsof dissolvedoxygen' water clarity and chlorophyll a' Correct diffirsion tion of vertical mixing, including the simulation of vertical eddy dissolved coefhcientsin the hydrodynamicmodel is particularlyimportant for the oxygen oxygen criteria as the principal barrier to vertical movementof dissolved the hydro- frori surfacewatels to the deep water is the pycnocline simulatedby dynamicmodel. hydrody- The tlydrodynamic Model was applied to generatea l0-year record of simulated namic transport for the Water Quality Model The years that were are (1985-94) cover a wide hydrologic range' The years 1985, 1988 and 1992 years;and considereddry years; 1986,1987, 1990 and 1991are consideredaverage a dry 1989, 1993unO tSS+are consideredwet years'Although 1985 is considered over the year overall, in Novemberof that year the track of hurricaneJuan swept flows at the fall upp". Potomu"and Jamesbasins and generatedhundred-year-storm lines ofthese nvers.

{itr;rF)tcr ii ' Ovilrvle\,vof lechnir-alfcol: As llsname implies,the HydrodynamicModelmakes computations on a generalized curvilinear,or boundary-fitted,horizontal grid, i.e., the grid from the planar view follows the shapeof the Bay's shoreline.However, to ensurethat long_tem stratifi_ cation in the deepchannels is maintained,the vertical grid, correspondingto depth, is Cartesian. Boundary-tittedgrids in the horizontalplane allow for a betterreore_ sentationof the shorelineboundaries of rhe ChesapeakeBay, as well as intemal featuressuch as channelsand islands(Figure ll-g). Mathematical simulations of all physical processesinfluencing circulation and mixing in water bodiessuch as ChesapeakeBay are includedin the Hydrodynamic Model. These include freshwater inflows, tides, wind forcing, Coriolis forces,

Figure ll'8. Planview of the ChesapeakeBay Hydrodynamic or CHjD lvlodelboundary titted grid. Sour(e:Cerco and Meyers ?000. r h.JptL-r ii - C,"r:rvicw of li.chnicallools surface heat exchange and turbulence. The vertical turbulence closure model computesthe eddy viscosity and difi:sivity from the kinetic energyand dissipation 'k-e of the turbulence.This type of closuremodel is known as a turbulencemodel" Turbulence is produced by wind stress at the surface, velocity shear in the water columl andbottom friction. Densityeffects due to salinity andtemp€rature are fully coupledwiththedevelopingflowheld.Thus,advection/diffiisionequationsforthe saliniry and temperatureare solved along with the conservationof mass and momentum equations for the flow freld. Completedocumentation of the HydrodynamicModel can be found in "Chapter2: Valid-ationand Application of the SecondCeneration Three-Dimensional Hydrody- namic Model of ChesapeakeBay" of Tributary Reiinementsof the ChesapeakeBay Moti':l (Cercoet al. 2002a)available at: http://wwwchesapeakebaynet/modsc htm under *JreDocumentation tab.

WATERQUALIry MODEL is three- The Water Quality Model, based on the CE-QUALJCM code, a dimensional,time-variable model of eutrophicationprocesses in the watercolumn and bottomsediments. As appliedto the ChesapeakeBay andits tidal tributaries,the model is part ofa packageihat includesthe ChesapeakeBay WatershedModel and the ChesapeakeBay Airshed Model describedpreviously. Th€ water quality model is linked to the hydrodynamicmodel and uses complex nonlinear equationsdescribing 26 state variables relevant to the simulation of dissolvedoxygen, water clarity and chlorophyll a (Cetco and Cole 1995a,1995b' 2000;Thomann et al. 1994;Cerco and Meyers2000). The statevariables include the futl suite of nitrogenparametels (ammonia, nitrate, total nitrogen,dissolved labile organic nitrogen, dissolvedrefractory organic nitrogen, particulatelabile organic niiogen and particulate refractory organic nitrogen) and the equivalent set of phosphorusand carbon parameters.Dissolved oxygen is simulated as the mass Lalancecalculation of reaerationat the surface,rcspiration of algae, benthosand underwaterbay grasses;photosynthesis of algae,benthic algaeand underwaterbay grasses;and the diagenesis,or decayoforganics, by microbialprocesses in the water iolumn and sediment.This massbalance calculation is madetbr eachmodel cell and for associatedsediment cells at each hourly time step, providing an estimateof dissolvedoxygen from nutrient loads from the watershedand airshedto the waters of the 35 major segmentsof the ChesapeakeBay and its tidal tributaries Water clarity is estimatedfrom the daily input loads of sedimentfrom the watershedand shorelineacted on by regionally-calibratedsettling mtes, as well as estimatedadvec- tion due to hydrodynarnics.Chlorophyll a is estimatedbased on Monod calculations of algal growth given resourceconstraints of light, nitrogen,phosphorous or silica AIso, threebasic phytoplankton groups, including greens,blue-greens and diatoms' are simulated.Algal limitation is simulatedby Michaelis-Mentonkinetics, with the resourcein leastsupply providing the limitation to growth' Completediagenesis is simulatedbetween the water column and sedimentas organicssettle to the bottom' are incorporatedin the sediment,undergo decomposition, and are ultimately simulatedas a retum flux of nutrientsto the water column' or as deepburial (DiToro and

clrrJrtr-'r ii . Ovllrvirg/of Tt:chnicalTrrl-ris Fitzpat.ck 1993). Lastly, simularionof SAV in shallow watersrs coupredwith the model(Cerco and Moore 2001). Completedocumentation ..Chapter of the Watereuality Model can be found in 3: Tributary Refinements ,.Chapter to rhe Chesapeakeday Model,, and +: irhyto_ plankton Kinetics in rhe ChesapeakeBay EutrophicationModeli of Tribuiary Rertnementsof the Chesapeake Bay Mottel (Ceico et al. 2OO2a)available at: http://www.chesapeakebay_net/modsc.htm undei the Documentatlontab. Further informationon the model can be found at the sameweb site in the document Three_ DimensionalEutrophication Motlel of rhe ChesapeakeBay (Cercoand Cole 1994). Additional detaileddocumentation of this rnod"'l i, .urr"ntty being developedand will be availableat the aboveweb site in Spring2004.

WetlandSediment Oxygen Demand During the most rec€ntrefinement and recalibrationof the Water euality Model, processesslmulating the incorporationofoxygen -Bay demand by wetlandsediment were built in. In some regions of the Chesapeaki tidal tributariessurface waters, a naturaloxygen deficit below saturationlevels is typically observedin the summer. Theseregions are tbund adjacentto extensivewetlands and contain comparatively small volumesof water. Th1^ti_rflfresh and oligohalineregions of the n4attaponi (segmentsMPNTF pamuntey and MpNOH) and (segmenr*"pMftp and pMKbH) rivers,respectively, are two specificexamptes. on tne*otnerhand, regions ofthe Bay tidal waterswhere thereare extensivetidal wetlantlsbut are borderedby relatively largebodies of water, suchas the TangierSound, have sulficient water volumesand mixing to mask the naturaloxygen demand of adjacentwetland sediments. In the segmentswith extensivetidal wetlandsand small volumesof water,oxygen demand from wetland sedimentsis thought to influence surfacewater dissolved oxygenconcentratrons. Recentstudies estimate wetland sediment oxygen demand to rangefrom | - 5.3 g o2rm2-day(Neubauer et al. 2000;cai er ar. 1999).In the model, a uniform oxygendemand, of 29 O2/m2-daywas used. The wetlandsediment oxygen demandis univenally appliedin the model basedon GIS estimatesoftidal wetland area(Cerco and Noel 2003).

SAVModel Three_components arerequired for a systemwideSAV model.The first is a unillevel model of a plant. The second is a Water euality Model (describedabove) that provides light, temperature, nutrient concentrationsand other forcing fi.rnctionsto the plant component. The third is a coupling algorithm that links the systemwide environmentalmodel to the local_scalepLnt mo

ADJUSTMENTOF MODELDISSOIVED OXYGEN, WATER CLARIry AND CHLOROPHYLLA ESTIMATES Act)' To generatethe modified rlataset for a particularscenario (e'g', 2010 CleanAir compared the-EPAcompared the trequencydistribution output from a scenariowas with the frequency distribution output of the model calibration Data were compared on a month-by-monthbasis For example,Figure II-9 illustraiesthe hypothetical frequencydisiribution for dissolvedoxygen concentrationdata in the deep-channel ofihesapeake Bay mainstemsegment CB5MII. The deep-channeldissolved oxygen criterion is applied May I through September30 From this graphone could infer that the modii was estimatingthe observeddata fairly well, sincemodel-simulated output matchesthe mean, approximatesthe rangeand has the samecharacteristic as the frequencydistribution ol the observeddata However' despite the shape 'dissolved u"a"ptublacalibration, if the criterionhad beenset as oxygen concentration of< 2 mg literl no more than l0 percentofthe time', the model would indicate 'pass' 'fail" a while the observeddata would indicatea during For eachpoint along the frequencydistribution where an obsewationexists and the 1985-1994period, a mathematicalrelationship between the model scenario the the model calibiation was establishedby regressingthe 30 or so daily valuesfor month when the observationoccurred in the water quality model cell that contains the observation.Figurc It-10 compalesthe hypotheticaloutput of a Water Quality

chat)tcr ii . Ovcrui':'rvof lechnic'r iool: I .68 o !; cl 3 ^e o c ="bc o- >< tr4 -.1

OVo 10o/o zOVo 3OVo 4oo/o 50o/o 60% 70% AOo/og}yo l}Oo/o Cumulalive Frequencyof Occurence

Figure ll-9 Frequencydistribution of hypotheti

9 .Eg

-a cl o E^ 6 ()k- c qt-c.Y 4 o'-{-E rc3 ot

iil .g o,l

OVo 10% 20% 31o/o4OYo 50o/o 6}yo TOvo AOo/ogO% 1OO% CumulativeFrequency of Occurence

figure ll- t 0. Frequencydistribution of hypoth€ticarobserved data, moder caribration and modelscenario for a designateduse. Source:Linker et al.2002-

, hill)tL r ii . llvcrvie,/r'of lichnicai fools Model scenariobased on a given load reductionto the Water Quality Model output calibration.These are shownon a frequencyplot so that changesin the predictionof attainmentcan be seenalong with the blue line ofthe observeddata Figure II-ll shows the relationshipbetween the calibration and scenarioWater the Quality Model output in more detail. By regressingthe scenariooutput against calibration output, one can find a relationshipthat can be used to transform the observeddata set. The regressiongenerates a unique equationfor eachpoint and month that transformsa calibrationvalue to a scenariovalue. This relationshipis then appliedto the monitoredobservation as an estimateof what would havebeen observedhad the ChesapeakeBay watershedbeen underthe scenariomanagement ratherthan the managementthat existedduring 1985-1994. Once the relationshipbetween the calibrationand any particularscenario is established,this relationship(applied as a regressionequation illustrated in Figure II-12) 'scenario-modified' is used to generatea observeddata set for the scenario The 'scenario-modified'values represent an estimateof an observeddata set underthe conditionsofnutrient and sedimentmanagement represented by the scenario Each observedvalue for dissolvedoxygen, chlorophyll a and light extinctionin the 1985- 'scenario-modified' 1994data set is replacedwith a value. For a full discussionof this procedure,see A Comparisonof ChesapeakeBay Estuary Model Celibration lfith 1985-1994 Observed Ddta and Methotl oJ' Application to Water Suality Criteria (Linker et al. 2002) available at: http://www.chesapeakebay.net/modsc.htm under the'Documentation' tab'

Calibration

Figure ll-1 1. Exampleof a regressionbetween model calibration and scenariodata' source:Linker et al.2002.

ch.rf)te-r ii - Ovcrvii:r,vof ir:cfnica Tools Y

I .E8 E, cl 36 ;bc Ior4 xtr 'clo=3 >t 6- .o1 o 0 0% lOoA 2lo/o sDo/o 4\yo 5}o/o OOo TO% BOo/o9O% 1}0o/o Cumulative Frequency of Occurence

Figure ll-12, Exampleof the regressionequation applied to the observed, Sou.ceiLinker et al.2002.

MANAGEMENTAPPLICATION OF MODEL OUTPUT5 Apart from the adjustedmodel output that is usedfor assessingaltainment of the three criteria,.it is useful_toexamine the degreeof model calibrationin eachdesig_ nateduse within each ChesapeakeBay program segmentwhere the water quality model will be applied to assessthe quality/accuracyof the model calibration.For this purpose, a strict one-to-onecomparison is madebetween the obsewedand simulated data.The comparisonsare made for the sametime (observedand simulated) and space(real and virhral). A set of empirical decisionrules were developedibr the purposeof assessingthe quarity ofth.ralibration for eachchesapeake Bay programsegment designared-uses (Table II- I ). The relariveperformance ofthe predictedmetric (e.g.,dissolied oxygen concentration) comparedto the observedmetric underthe decisionrules was iaied 'high .moderate .low as certainty', certainty',or certainty,(Linker et al. 2002). One comparisonthat wasmade was the centraliendency, the meanor median,ofthe data. Another was the dispersion,or standarddeviation. Range comparisons ofthe minimum or maximum were also employed, as well as examination oithe frequency and scatterplots. A relativeconfidence estimate ofmodel calibrationwas determined lrom the summarystatistics and statisticalplots of all the comparisons.Best profes- ' sionaljudgement was usedin caseswhere most, but not alr, ofthe criteriaweie met. While the open-waterdissolved oxygen criteria apply year_round,emphasis was on the periods critical for the living resourcesprotected by the criteria.Evaluation ofthe mlgratory spawningand nursery dissolved oxygen criteria focused on the latewinter r:lr.rptcrii . Ovcrvtelvof lcchnicallool: Water Table -1, The relativeconfidence in modelcalibration findings were used directly by the committeein makingi"gg"T:ll: QualityTechnical Workgroup and WaterQuality Steering "-: 1: exactliwhere the watei quility modeloutputi couldbi usedfor settingthe cap load allocations. Best Standard Professional Judgement R! Mean Difference Deviation Dissorvedoxygen>0.5desirabre Do not differ by l:,'ilt"[1,!HXlijjl,f"f]l more than 0.5 diller by more than 2.0 mg litert

Chlorophylla >0'2 desirable Not greaterthan two times the Do not differ by more concentrunon;maxlmum than threetimes the concentrationdo not diffcr observedstandard more than 20,0 mg liter-r deviation more WatcrClarity >0.2 desirable Not greaterthan two times the Do not diller by concentration;maximum than two standard concenrationdo not diller deviations by mqre than two times Kc

Sourcc: Linker et al. 2002.

to late spring period, while evaluationof the open-water,deep-water and deep- channeldissolved oxygen criteria focusedon Junethrough September' A summary of the relative confidencein model calibration by ChesapeakeBay Program segment by designateduse is provided in Table II-2' More detailed infoLationln the ChesapeakeBay water quality model calibration is available at: http://www.chesapeakebayneVmodsc.htm under the publicationstab and within the report A Comp)rison of Chesapeake Bay Estuary Model Calibration llith tgls ig94 ObservedData and Method of Applicalion to WaterSuality Criteria (Linker et al. 2002).

ro:lnnical ( hilpler ii - Ov'.:rvi'"woi Tooi! Tablell-2' Relative confidencein chesapeakeBay water quality model calibrationfor 35 chesapeakeBay Programsegments for the three chesapeakeBay water quaritycriteria by tidar water designateduse.

DissolvedOxygen Chlorodhyll4 ChesapeakeBay Migratory OpenWrter Deep Deep Water ProgramSegment FeLJune All Year Water ChallDel Spring Summer Clarity TF b cB20 CB c cB4 CB b CB6PH CB

Key: a: Iligh Certainty b = Modemre Certtinty c = Low Certainty

Source:Linker et al. 2002.

ch.rpter ii . Cvervrcwof fcchnrraliirols LITERATURECITED

Appleton,E. L., 1995.A cross-mediaapproach to savingthe ChesapeakeBay' Ettvi'anmental Scienceand Technologt29(.12): 550-555-

Appleton,E. L., 1996.Air quality modeling'sbrave new world: A new gencrationofsoftware sysiemsis setto tackleregional and muttipollutant air quality issues EzvironmentalScience arul Technolog 3015)pp 200A-204A.

Bicknelt, B., J. Imhoff, J. Kittle, A. Donigian, R. Johansonand T Bamwell 1996 Hldro' logic Siur ation Progrcm - Fortran rser's manual lor release ll' US Environmental ProtectionAgency EnvironmentalResearch Laboratory Athens,Georgia'

Brook. J.. P Samsonand S. Sillman. 1995a.Aggregatior ofset€cted three-day periods to csti- a mate annual and seasonalw€t depoiition totals for sulfate,nitrate, and aeidity Part li synoptic and chemical climatology for eastemNorth America Jourual of Applied Meteo' rologlt 34:291-325 . to esti- Brook,J., P Samsonand S. Sillman. 1995b.Aggregation of selectedthree-day periods ll: mate annual and seasonalwet deposition toials for sulfate, nitrate, and acidity. Part Applied selectionof cvents,deposition totals, and source-r€ceptorrelationships Journal of M eteorobg1t 3 4:326-339.

Cai, W. J., I-. R. Pomery,M. A. Momo andY Wang. lggg Oxygenand carhon dioxide mass balancefor the estuarine-intertidalmarsh complex of five rivers ir the southeastemU-S Limnologyand Oceanography44(3):639 449.

Cerco, C. F. 2000. Phytoplanktonkinetics in the ChesapeakeBay EutrophicationModel' WaterQu.tlity dnd EcoslstemModeling l(14):5-49 of Cerco, C, F. 1995a. Responseof ChesapeakeBay to nutriert load reductions Joumal EnvironmentalEngineering l2l (8):549-556.

Cerco, C. F. 1995b. Simulation of long term trends ill ChesapeakeBay eutrophication Journal of EnvironmentalEngineering l2l(4) 298-310

Cerco,C.F- and T. Co1e.2003. The 2002 ChcsapeakeBay EutrophicationModcl EL-03-XX' C€ntcr, Vicksburg' [in preparation]U,S, Army Engineering Researchand Dev€lopment Mississippi. for Ccrco, C. F. and K. Moore. 2001. System-widesubmerged aquatic vegetationmodel ChesapeakeB^y. Esta.lries24{4):522-53 4-

Ccrco,C. F.and M. Meyers.2000. Tributary Relinementsto ChesapeakeBay Model Jounal of Environmental Engineering126(2\-164-17 4.

Cerco,C, F. and T. M. Cole. 1994 Thtee-DimensionalEutroPhication Model of the Chesa' peak Ba! Volumel: Main Repofi lJ.S' Army Corps of EngineersWatcrways Experiment Station,Vicksburg, Mississippi.

Cerco,C. F- anrl I M- Cole, 1993 Threc-dimensionalcutrophication modcl of Chesapeake Bay.Journal oJ EnvironmentalEngineering I l9(6):1006-1025'

Cerco.C. F..B. H. Johnsonanrl H. V. Wang.2OO2a. Tributary Rertnements to the Chesapedka BuvMorlel.FinalReDortERDCTR-02-4.U.S.ArmyCorpsofEngineers'Washington'DC

ch.rpt.'r ii - Ovcfviewol Techni.allools Cerco, C. F-,L. Linker,J. Sweeney,C. Shcnkand J. Butt. 2002b.Nutri€nt and solidscontrols in Virginia'sChesapeakc Bay tributaries.Joumal ofl{ater Resourcesplanning and Monage- ment May/ June:.l7 9-189. Chang, J., B Middleton, W Stockwell,C. Walcek,J. pleim, H. Lansford,S. Madronich, F. Binkowski, N. Seamanand D. Stauffer. 1990.The RegionalAcirl DepositionModel and EngineeringModel, NAPAp SOS/T Rcport 4. lN NationalAcid precipitstion Assessment Program: State of Science and Technologt, ,/olume l. National Acid prccipitation Assess- mcnt Program,Washington, D,C. Chang J., R. Brost, [. Isaksen,S. Madronich,p Middleton, W Stockwell and C. Walcek. 1987. A three-dimensionalculerian acid depositionmorlcl.physical concepts and formula- tion. Joutnal of GeophysicalResearch 92: l46gl-14700. Chesapeake ExecutiveCouncil. 1987.Cheupeake Bay Agreement.Annapolis, Maryland. Chi, W., y, L. Pomeroy,M. Moran and Wang. 1999.Oxygen and carbonmass balance for the estuarine-intertidal march complex of five rivcrs in the southeastemIJ.S. Linnologt and Oce a nography 44 :3, 639-649. Dennis, R. L. 1996-Using the RcgionalAcid DepositionModel to determinethe nitrogcn depositionairshed of the ChesapeakeBay watershed.In: Joel Baker (ed.). Atnosphiric Depositio\ to the Great Lakes dnd Coqst.tl lyaters. Socj,ctyof Environmental Toxicotogy and Chemisrry Dennis, R., F. Binkowski,T. Clark, J. McHenry S. Reynoldsand S. Seilkop. 1990.Selected applications of the RegionalAcid DepositionModel anrl EngineeringModel, Appendix 5F (Part 2) of NAPAP SOS/T Reporr5.ln National Acid precipitarion Assessmentprogrum: qnd StateofScieace Technologt,I/olume l.Narional Acidprecipitation nssessment program, Washingron,D.C. Di Toro, D. M. andJ. J- Fitzpatrick.1993. Chesapeake Bay SedimentFhLr ModeL ReportEL- 93-2. U.S,Army CorpsofEngineers Waterways Experiment Station and U.S. Environmental ProtectionAgency ChesapeakeBay programOffici. pp. 198. Donigian, patwardhan, Jr, A-, B. Bicknell,A. L. Linker,C. Chang,C_ and R, Reynolds.1994. Chesape.tke Bay Prcgram WaterchedModel upplication to calculate bay nutrient lo.ldings. Report protection tbr the U.S. Environmental Agency, ChesapeakeBay program Offrce, Annapolis,Maryland. Hartigan, J. 1983, ChesapeakeBay basin model-Jinalrcport. Reportfor the U.S. Environ- mcntal Prot€ctionAgency ChesapeakeBay program,Annapolis, Maryland. t{opkins, K., B. Brown, L. Linker and R. Mader. 2000. ChetapealeBay WatershedModel land use and model linkages to the uirshed and estuarine models. U.S, EpA ChesapeakeBay Program,Annapolis, Maryland. http://www.chesapeakebay,net/pubs/l l27.pdf. Langland, M., P Lietman and S. Hoffman. 1995.gya theiis of nutriefi qntl sedimentdatafor watershedt wirhin the Chesapeake Bay druinage basia. Rcport 95_4233. USGS Water- ResourcesInvestigations,

Linker, L. 1996.Models of the ChesapeakeBay. Sea Technology37(9):49-55. Linker, L., c. Shcnk,P Wang,C. Ccrco,A. Butt, p. Tangoand R. Savidge.2 O02.A Compar- ison,ot cheltapeake Bay Estuary Mode! calibratio, with rgg5-tgg4 ob,erved Data and Method of ApplicutioL to tyater euality Critefia, ChesapeekeBay prcgram Modeling SubcommitteeReport ChcsapeakeBay programOflice, Annnapolis,Maryland.

. h-rptcr i - 0',,crviewof lechnicalfools Link€r. L.. G. Shenk,R. Dennis and J- Sweeney.2000.Cross'media models of the Chesa- peakeBay watershe

Madden,C. J-, M. Kemp andW. Michacl. 1996 Ecosystemmodel ofan cstuarinesubmersed plant community: calibration and simulation of cutrophication responses Estuaries 19(28):457-47 4. Robbin Maizel, M., G. Muehlbach,P' Baynham,J Zoerkcr,D' Monds,T livari, P' Wellc' J to ground and and L Wiles. 1995. Thepotential for nutrient loadingslrom septic sistems surfdce waler resorrces and the ChesapeakeBal RePort lbr ChesapeakeBay Program Offrce,Annapolis, Maryland. Moore, K. A-, D. J. Wilcox and R J. Orth. 2000. Analysis of the abundanceof submersed aquaticvegetation communities in the ChesapeakeBny. Estuqries 23( I ): I 15-127- freshu'atermarsh Neubauer.S., W. Miller and I Anderson.2000. Carboncycling in a tidal ccosystem:a carbongas flux study.M.r,'itle Ecologt ProgressSerres 199:13-30- Nitrogsn: Paert,H. W., R. L. Dennis and D R. Whitall, 2002. AtrnbsphericDeposition of lmplicationsfor Nutrient Over-enrichmentof CoastalWate:s' E$tuaries 25(.48):611-693'

Pahce,M-, J. Hannawald,L. Linker, G. Shenk,J. Stodck and M Clipper' 1998-Appendix tl: r:xckingbest managementpractice nutrient reductionsin the ChesapeakeBay Prcgram' l,r: ChesaleakeBay wtirersheiModel applicltion akd calculatio,nof nutrient and sediment rr..r. EPA 903-R-98-009,CBP/TRS 201/g8 ChesapeakeBay Program Office' Ar,'lrpolis, Maryland. :-lrrr'. W C. and G. R. Carmichael.1992. Sensitivity of acid production/depositionto emls- ' fcductions-Environment..l Science and Technology26:4 pp 715-725'

fhornann,R,V,J.R.Collier,A.Butt,E.CasmanandL'CLinker'1994Responseofthe Trarsfer Report Chrupeake Bay Water Quulity Model to Loading Scenarios Technology CBPi iRS l0l/94 (April, 1994)Chesapeake Bay ProgramOllice Anmpolis' MD Laboratory USDi\. 1984. Soil ConservatioflSeryice Soil InterpretationRccords Statistical towa StateUniversit, Ames, Iowa. Bq) Desig- U.S. EPA.2003a. kchnical SupportDocument Jbr ldentifcation of Chesapeake Officc' nated uses dnd Attainabiliry. EPA 903-R-03-004. ChesapeakeBay Program Annapolis,Maryland. WaterClatity and U.S. EPA 2003b.Ambiant WarerQuality C teria for DissolvedOxygen' Chesa- Chlorophytl alor the ChesapeakeBay and lts Tidal Tributalres-EPA 903-R'03-002 peakeBay ProgramOfftce, Annapolis, Maryland. in the U-S. EPA. 2002. Nutrie t Re(luction Technology Cost Eslimationsfor Poin! Sources Chesapeake ChesapealceBdy Watershed.Nutrient RcductionTechnology Cost Task Force Bay Program.AnnaPolis. Maryland Environmental U.S. EPA. 1994.Chesapeake Brry vtate$hed pilot prciect' EPA/62O1R-94- Monitoring and AssessmentProgram Center, Research Tria[gle Park,NC- generatron Wang,H. V and B. tl Johnson,2000 Validationand applicationof the second gualit) Ecosystem three'dimensionalhyrirodynamic model ofchesapeake Bay. water dnd Modeling l(l-4)51-90.

-iool5 <.fraptcr ii . Overvicw of ltchni{al Wang,P., L. Linker and J. Stonick. 1997.Appendix D: precipitationand met€orologicaldata devclopment and atmospheric nutrieqt dep;sition. tni Ch"sopeake Bay WaterchedModel antl calculation lpllicalion oJ nutrient and seclimentloatlings_phase'lV ChesapeakeBay WatershedModel. EPA 9O3-R-97-O22,CBP/TRS l8l/97, Ch'esapeakeBay programOffice, Annapolis,Maryland.

Wetzel, R. and I{. A- Neckles. 19g6. A model of Zosterq marinq L. photosynthesisand growtht simulated eff€ctsofselected physical_chemical variables and biologrcal intcractions. Aquutic Botany 26:307-323.

.:fr,tfrt.'rii - Ovcrvcwof icchnirallools chapter llN Technicaland Modeling Considerationsfor Setting the Cnp LoadAllocations

using the Water In calculating-ne""s.ury attainability rmder larious loading scenarios Quality technical Model, it is to apply innovative approachesto addressvarious follows: issues.The most important of these issuesare described in this chapter' as refining estimates oi pycnocline depths; setting averaging periods for determining criteria attainment;defining allowable frequency and duration ofcriteria exceedances; the ing ttt" g"ogrupniJ ittfl,rett"e of loads on tidal water quality; establishing of "rtutti.ttidal wettaid infl.."o"" on tidal-wat€r dissolved oxygen; analysis of the isolation individual pollutant effects on water quality; influence of sedimentloads on dissolved oxygen; and the establishmentand assessmentof SAV restoration goals'

REFINING ESTIMATES OF PYCNOCLINE DEPTHS biolog- The pycnoclineis usually characterizedby shong gradientsin chemicaland i*t p.op".ti"t and separatesthe deep,saltier waters from the lesssaline' well-mixed on the surface waters. In the ChesapeakeBay' another well-mixed layer forms stratifica- bottom of the estuary due to bottom shear frorn estuary currents' Vertical tion of the ChesapeakeBay has implicationsfor use designationsand' therefore' The accurateestimatei of the pycnoclin- are important for assessingattainment et al' methodfor assessinguppei-arrd lower mixed layer depthsis basedon Fisher (2003).This methoddiffers from the standardheld methodin that it usesa measured iensiiy gradient based on salinity and temperature rather than on the surrogate' of Generally,the uppeipycnoclinedepth is the shallowestoccurrence "ondu"tiuity. is the a density gradlent ofb.l kg/rna or greaterand a lower mixed layer depth exists' ,leepestoclunence of a densitygra

CapLoad Allocalrons ( lrnpt.rr iii - lt{hrrr(dl,lnd Morlclinq Considcration5 for 5ettirrqlhe AVERAGINGPERIOD FOR DETERMINING CRITERIAATTAINMENT The method-for determiningattainment of the ChesapeakeBay dissolvedoxygen, clarity and chlorophylla criteriabecame an issue.Chesapeake Bay programpartiers decidedthat the Bay modelingtools wouldbe usedto assistin allocatingthe;ufient and scdiment cap loads,and the ambienttidal water quality monitoringdata would be usedto ultimatelydetermine criteria attainment forlistin! anddelisting purposes. This course of action required greatercoordination betwelen monitorine data and modeling output assessmentsand decisionson the methodfor analyzingitonitoring data.

ASSESSINGMONITORING DATA Monitoring criteria attainmentrequires reconciliation of dichotomousneeds. Long averagingperiods are neededto oblain the best assessmentof criteria attainmen-t through wet, dry and averageyears. Data from multiple yearsaverages out other interannual variability, such as the timing of high flow ani load events.The large nutrient and sedimentload reductionscalled foi in the Chesapeake2000 cap toid allocations will occur in different places and at different rates, thereby;dding more variability to interannualmeasurements of dissolved oxygen, ctarity ani chlorophyll a. All of these factors addressassessing attainrnent with the longest monitoringperiod practicable. On the other hand, responsivewater quality managementrequires a reasonable assessmentperiod, which requiresa compromiseon the quality of assessment.To best addressthe dispamteneeds of quality and responsiveness,a three_yearaver- aging period was chosen. See chapter 6 in the Regional criteia cui.rance for a detailedjustific'ation for the serectionof this averagilngperiod (u.s. EpA 2003a).

ASSESSINGMODELING D,ATA Currently, chesapeakeBay water euality Model outputis availabrefbr l0 simulated years (19,85-1994),which provideseight three_yeairunning averages(19g5-19g7, 1986-1988,1987-1989, etc.). To comparethe itandard l0lyear assessmentof the model outputs for dissolvedoxygen, clarity and chlorophyll d to the three_year assessmentof monitoringdata, the model ouhut was mod-ifiedto provideestimates of the highest attainmentof the eight three_yiarassessments, the lowestattainment of the three-year eight assessmentand the averageof the eight three_yearrunning assessments.The modificationallows for .best, 'worst' assessmentof model estimated and casesof altainmentusing a running three-yearassessment penod. The deep waiers of the middle mainstem ChesapeakeBay segmentsCB3MH, C_B4MHand CBSMH, along with the rleep wateis of the iower potomac River (POTMH) and EastemBay (EASMH) form a largecontiguous region of deepwarer in closecontact with the often anoxicwaters oftie deep-channel.Attainment ofthe dissolved oxygencriteria for thesedeep waters is difficult, as FigureIII-l illustrates. Sevenscenarios areshown: 1985,94 Observed, 2000 progress,iiet l, Tier 2, Tier 3, chlpt{rr iji - ,fcchnical andModr.linq Ccnsidr:rations for Sctiirlgthe Cop Lo;rl Allocation: DODeeP

CBSMH cBaMH CB5MH PorMH *tI" Ad,€ .$e *s "S *o"s ..+$i.."r$*$i'""e**r$"""$;$s5*"^,"$'+"$:"41$ i i I 20 l-Hish

l-10Yravg | -ror"rr vtSYc_ IIr I 5ro z, .1lr ;{ 5 rrrr=:_ Ilhr"-lIr=- l- 3E InII=-- o S€gmsnts& Scenarloa

dissolved Figurelll-1- Assessment of the range and mean oJ a three-yearrunning average based on modelestimates.of P6TMHand EA5MH' oxlgencriteria attainment Jor the d!'ep waters o{ thecontiguous region ot CB3MH,C84MH' CB5MH'

Tier 3+20% ShorelineSediment Reduction, and Trial 2 (basinwidecap loads) The 'Not ' lO-yearaverage of waiers in Attainment'(labeled 1O-yravg') is approximated by the averageof the eight tbree'yeatnmning averages(labeled'Total 3-yr avg')' Moreover,as nutrient and sedimentloads move toward the agreed-uponbasinwide cap load values(Trial2 scenarioin FigureIII-1), the l0-year average,the averageof the eight three-yearaverages and the high and low three-yearaverage begin to approachthe samevalue. The mainstemCB4MH segment,located in the middle of the deep-channelanoxia regionofthe ChesapeakeBay, has the greatestdifficulty in attainingthe deep-water dissolvedoxygen criteria.Figure III-1 indicatesthat the l0-year averageestimate of nonattainment(19 percent)is close to.the averageof the eight three-yearrunning averages( I 8 percent)and that the worst thee-year averageperiod of nonattainment (23 percent)is, of course,greater than the bestthree-year average of nonattainment (16 percent).As the loadsof nutrientsand sedimentare reduced,the levelsof nonat- 'best' 'worst' tainment decreas€,and the range between and three-yearaverage nonattainmentdecreases. Model estimatesof the rangeand averageofthe three-year averagesof tlissolvedoxygen, clarity and chlorophylla providean estimat'eof what attainmentmay look like using a three-yearrunning averageof observations'

ch.rpter lii - rtechnitaiand MotlclinqConsliietations for 5ettin!J the CapIOad /rilccaiions $f f

Civen the findings that l0-year and 3-yearaveraging periods tbr determiningattain- m€nt were very close at loading levels approachingthe basinwidecap loads,the Chesapeake Bay Programpartners decided the l0-tear averagedmodeling output could be usedin making cap load allocationdecisions.

DEFININGALLOWA,BLE FREQUENCY AND DURATTON OF CRITERIAEXCEEDANCES Waterquality criteria 'safe'levels are establishedas necessaryfor the protectionof aquaticlife. Continuedattainment of theselevels should result in a healthyaquatic community.Typically, the EPA'Snational water quality criteriaare fudher d;fined by magnitude, maximum durationand llequency of exceedances.Although it is well- estabrishedth€t exceedancesof water quarity criteria within timits sit supporta healthyaquatic community,the ChesapeakeBay programidentified the need'togo beyondthe simple time metricsof frequencyand duration that are usually applied. An innovativeapproach wasadopted based on allowableexceedances of time Grcent of time exceeded-with the criteria applicationperiod) and space(percent uolume or surfacearea of the designateduse within a ChesapeakeBay programsegnent). Monitoring for criteriaattainment requires collection of datathat are as fully repre- sentahveas possible of the extentof spaceand time over which the assessmentrs to be performed, but resourcelimitations inevitably limit datacollection. Therefore, an analytical ftamework is usedto evaluatespatial and temporalcriteria exceedance basedon limited data. As the monitoring programwas being designedfor criteriaassessment, the scientists involved developed an analytical framework based on a cumulative frequency diagram(cFD) approach.Monitoring datacollected at a limited numberoflocations were interpolated over a fixed three-dimensionargrid. criteria valueswere defined for eachgrid cell and combinedwith the datainterpolation to providea cell_by-cell estimateofcriteria exceedance.Then, for eachmonitoring eveni, those grid-cel est! mateswere aggregated .percent to provide a segment_wideestimate of of space, ' exceedingthe criteria. Multipre monitoiing eventsconducted over an assessment period provided ,percent a temporallydefined collection of estimatesof of space, exceedingthe criteria. Those values were then plotted as a CFi using-criteria standard statisticar procedures.The cFD generatedusing this approachreflects 'percent rn ' both spaceand time since ofspace' is represented 'temporal on the horizontalaxis and frequency'is representedon the vertical axis (FigureIII_2; seeChapter 6 of the RegionalCriteria Guitlqncefor more derails)(U.S. ipe ZOO:a). As the CFD approach was developed,it was recognizedthat some spatial and temporalcriteria exceedancecould occur at the sametlme that the overall sesment was achievingits designateduse. For example,some small tidal tributaries;ight chronicallyexceed the criteria simply becausethey are naturally poorly flushed.It was decidedthat these 'alrowabte'and exceedancesshould be considered shourdbe accountedfor in the CFD analyticalframework r:hitpteriii - fcr.hnical andModc/inq Consrdcfitionr for Scttinq the (_,lp Lodd Allor.ations '100 o.9 Allainment Cuwe P6 90 Et, ,z 80 E6tso 70 q6 =o 60 oo (:r x o- Ul (o q, (!E 40 P€ FA 30 oE g< 20 E"b 10 fiE oo b> 0 (L 010203040 Percentage of AraaA/olume Exceedingthe Criteria

Figure lll-2. Non-allowableexceedance illusttated in dark blue' Source:lJ.5- EPA 2001a.

.allowable w€re To accounttbr exceedances'in the cFD apploach,multiple options the best consideretl.tnitially l0-percentof time and/or spacewas consideredto be adher- approachbecause it was consistentwith pastEPA guidance tlowever' strict tendto enceto a t0-percentrule almostalways resulted in a violation becauseCFDs there exceedlo-percent of time or spaceat somelocation on the figure, evenwhen the CFD and so are f'ewmeasured violations. A curvedline is more consistentwith 10- a mathematicallydefined hyperbolic line was developedthat encompassed was percentof the ifO ptot ."o. fnit approachappeared to function well' but achieve' consideredarbitrary because it had no scientificbasis with regardto actual ment of a designateduse. As a result,a third option was consideredwhere a CFD wasdeveloped based on datafiom areasthat werealready achieving their designated 'reference asa benchmark use.That CFD wasdefined as a curve'that woutd be used againstwhich other CFD assessmentcurves could be compared The biologically- 'reference and d-elined curve'was selectedas the bestaltemative ofthose considered Criteria adoptedtbr routineuse in criteriaassessment (see Chaptet 6 of flie Regional Guidancefor more details;U S EPA 2003a). Exceedancesin time andspace for modelwere determined with cumulativefrequency II' each distributions(CFDs) and biological reference curves' As describedin Chapter modelscenario was usedto createa modifieddata set for that scenarioThese results were then interpolatedand used to createCFDs of spatial and temporalcriteria and exceedancefor each segmentand designateduse The CFD for the segment the scenariowas compared to the appropriatebiological referencecurve that defines extent biologically acceplableand protectivecombinations of frequencyand spatial

(lln5iclerati{lns C'rpLoad AllocatLons .hJplc.r iii . icchnicaldncJ t/odeling for 5ctting th{r of criteria excegdances.The total areabelow the CFD for a segment,but abovethe biological refbrencecurve representsthe unallowableexceedaice for that segment and scenario(Figure III-2). Thesecalculations were automaticallycarried oui by a system of computerprograms available from the ChesapeakeOay pmgram Offrce. The development and applicationof CFDs is describedin greaterdetail in Chapter6 of the RegionulCriteio Guidance(U.S. EpA 2003a).

ESTABTISHINGTHE GEOGRAPHICINFTUENC.E OF I-OADSON TIDAL WATERQUALITY In developing the cap load allocations,it was key to understandeach major tributary's influence on tidal llay water quality. To assis!the Water euality Steering Committee in isolatingthe effectsof eachof the nine major basins,the Chesapeake Bay Program ran a seriesofgeographic isolation runs witi the Waterquality Niodel. The model runshelped estabrish estimates ofthe influenceofloads from eachof the nine major tributary basinson water quality in each segmentof the Bay,s tidal waters.Specifically, isolationscenarios, in which the managementcontrols were set at Tier 3 levels for the isoratedbasin and herdat year 2000-leversibr the restof the watershed, performed were for each major basin. Issuesin identifying the most affected segmentsand estimatingthe absoluteand relativeeffects were adtlressed. Absolute effectswere defined as the total efect ofa basinon waterquality, including loads,either large or small,and the geographicinfluence ofa basin;,po.ition in thi estuary(i.e., the Susquehanna,with the largestloads and a positionat the headofthe estuary always had the highestestimated absolute effect). Relative loadswere an estimate ofthe geographiceffect alone, irespective ofthe amountofthe load,so that for upperBay patuxent regions,the westernShore an; wereestimated to haveabout the same relative effect as the Susquehanna.The cap load allocationassessments took estimatesof both the absoluteand relativeeffects into accounl

FOCUSINGON MAINSTEMSEGMENTS CB3MH,CB4MH AND CB5MH As described above, the Bay tidal-water area that requires the highest level of nutrient reduction to attain dissolvedoxygen criteria is the deep_waterand deep_ channel designateduse in the middle and central ChesapeakeBay (segment CB4MH). Hence, all other tidal Bay habitatsthal arenot cunendy in attainmentfor dissolvedoxygen would come into attainmentbefore the CB4MH deep-waterand deep-channel designateduses were fully in attainment.For this reason,the Waler Technical Quality Workgroup focusedon segmentCB4MH when comparingthe influence of difrerent basins.This focus was later broadenedto include seg-ment CB3MH and segmentCB5MH, respectively,since tley werenear segment CB4MH and also requiredhigher levelsof nutrientreduction to reachattamment-

COMPARINGABSOLUTE VERSUS RELATTVE EFFECTIVENESS ettlctrvenessgives an indication l\]lo'fte of the totaleffectiveness of a panicular basrnin reducingnonattainment in a given segmentby taking into accountgeog_ raphy and total load,while relativeeffectiveness takes into acciunt only geography. cfT,rpt.,.riii ' i:r (.cn:irli:rations hnical.rnrl Mode ling for!cttirjq the C,,rp Loltd n llo..ttions a Absolute effectivenessis the changein criteria nonattainmentthat results from It is singlebasin changing from year2000 levelmanagement to Tier 3 management' in the iarne units as the CFD, which is percentageof spaceand time in nonattainment."r,p:."s."d For example,if the lower PotomacRiver segmentPOTMH moves from 35 percentnonattainment to 30 percentnonattainment ftom the imPlementation percent' of Tier I in the Potomac basin, then the absolute effectivenessis 5 Comparingthe absoluteeffectiveness among basins helps to identify basinsthat can Figrre III-3 shows the have'the ireatest total effect in conecting nonattainment' absoluteJffectiveness of eachbasin on reducingthe deep-waterdissolved oxygen criteria nonattainm€ntin middle centralChesapeake Bay segmentCB4MH' Relative effectivenessis the absolute effectivenessdivided by the total load reduction in the necessaryto gainthat water quality response.For example,ifthe loadreduction in Potomacbasln was 5 million poundsof pollutant to get that 5 percentchange nonattainment,the relativeeffectiveness is I percentper million pounds'The relative effectivenesscalculation is an attemptto isolatethe effect of geographyby normal- izing by loa

3.50

3,00 -59 2.50 EE 88.2.OO 5s1.50 ?E1.00 i;E0.50

0.00 MaiorTllbutary Baalns

Figure llt-1. Absoluteeffect oI loadreductions from the ninemajor basins on seqment CB4MHdeep-water dissolved oxygen concentrations'

NORMALIZINGFOR THE COMSINED NITROCEN ATIIDPHOSPHORUS LOAD Sincethe reductionsthat cause the absoluteeffcct are taken across the board from nitrogen,phosphorus and setliment loads, one must determine the pollutant load type resno.-nsibiefoi the increased attainment' The Chesapeake Bay is bothnitrogen- and

(-h.rptcr iii . Tcchni.i:l;ntl l'/odr:lirrgaonsider'rli{rns fLrr' 5r:lting thc C'rpload Allocaiions phosphorus-limited in differentregions and seasons(D'Elia et al_l9g6; Fisheret al. 199,2, 1994,1999,2001; Boynton et al. 1995;Malone et al. 1996;Conley 1999).The spring algal bloom near the tidal-fresh and oligohaline regions is generally controlled by phosphorus.The summeralgal bloom, primarily in the mesohaline regions, is controlledmore by nitrogen.Low dissolvei oxygen conditionsin deep watersare causedby a combinationof theseseasonal blooms. Suspended sediment also has an effect on dissolvedoxygen, but its effect is lesst}tan the nutrienteffect (see Intluence of Sedimenton ChesapeakeBay DissolvedOxygen below). Sincethe effectsof nitrogenand phosphorusare inherentlyconnected in the Chesa_ peakeBay managementcontrol scenariosand cannoteasiiy be isolatedby separate managementpractices, the Watereuality TechnicalWorkgroup agreed that the most appropriate divisor to convert absoluteeffectiveness to ielative effectivenessis a combination of the two nutrients.Since nutrients are takenup by algaein roughly a l0: I N:P ratio (by weight),this ratio wasalso usedin the metric.Therefore, an atgal unit is defined as I unit mass of phosphorusand l0 units mass of nitrogen. Figure III-4 showsthe relative effectivenissof the nine different ma1orbasins on deepwater in segmentCB4MH, normalizedby algal units. To test if the waterquality responsewas further separable by basin,the Susquehanna River basin wasrun with a reductionin phosphorusonly, siice the tidal-freshwaters th-at-itempties into are typically phosphorus-limiteO.ngure III_5 showsthe results of this test in_the three mid-Bay segments.From this graph, it is clear that both nrrogen and phosphorus coming from the SusquehamaRiver basinboth havelarge effectson water quality in the mid-Bay region.

1.20

E! 1.00 E€o.80 EA €g 0.60 .:o 0.40 EE9.E' 0.20

0.00 MaiorTrlbutary B83tns

Figure lll-4. Relative effectof loadreductions from the ninemajor basins on segment CB4MH deep-waterdissolved oxygen concentrations normalized Uy uigaf unltr.

( h'rpt{}r 'ii ' rcchric,rr.rnd M.rlclinc; consicicrationsfor scttingihc cap Lo.rdArocat on5 3,5 E! 3.O =e =s.2.5 E is 2.O zE l-5 Hi1.0 5E0.5 0.0 C84MH CB5MH ChesapeakeBaY Program Sogmsnl

nitrogen Figure lll-5. Estimatedabsolute effectiveness of susquehannareductions of only ani phosphorusloads (N&P) compared to reductiontof the phosphorusload (p onty) on dissolvedoxygen criteria attainment in the deep waters of mid-mainstem Che5apeakeBay tegments C83MH, cB4MH and C85MH'

GENERALFINDINGS FROM THE GEOGRAPHIC ISOLATION RUNS hibutary Figure III-6 shows the absoluteand relative effectivenessof each major and suggests baiin on mainstemChesapeake Bay segmentsCB3MH and CB5MH than .o*e g"n"-tirutions. Northerntributarybasins have a greaterrelative influence southJmtributary basins,due to the generalcirculation pattems ofthe Chesapeake and the York Bay. Water and nutrients from the southem tributaries of the James proximity to rivers haverelatively less influenceon the mainstemBay due to their Bay also the mouth of the Bay, and the counter-clockwisecirculation of the lower mouth' tends to wash nutrient loads from these southern tributaries out of the Bay sincethey are situatedon the westem side of the Bay' This samecounter-clockwise circulationtends to sweeploads from the lower EastemShore northward Basinswhose loads discharge directly to the mainstemBay, like the Susquehanna' river estu- tendto havemore impacton the mainstemBay segmentsthan basins with (burial and aries(e.g., the Patuxentand Rappahannock),due to nutrient attenuation the mainstem denitrifl;ation) within the river eituariesprior to the watersreaching though ChesapeakeBay. The sizeof a basinis uncorrelaiedto its relativeinfluence' ofrela- largeriasins, with largerloads, have a greaterabsolute effect The-uppertier and tivJ effect in the three mainstemsegmints includes the largest(Susquehanna) into the Bay the smallest(Eastem Shore Virginiaj basins,both directly discharging 'up the without interveningriver estuariesio attenuateloads, and both current'to deep-channelregion ofthe mainstemChesapeake Bay (seeChapter IV)'

the CJpl-oad Allccaiions chapt.'r iii . l-ltchnrcal.rlrd i\''llodelingCon5idcratiorlsfor Seiting 1.00

0.90

_a 0.80 EE0.. EEo* 9o 9 r 0.s0 'iEn* gt gE ^^^ "w " 5 o.zo

0.10

o.00 MalorTflbutary Saslns

0.35

- n.rn EO o.n 'i6EP go. -__ g o uzu zE:tt E ai ",=-'" ;e Pt o.ro !! 6E o.os

0.00

Figure lll-6. (a, Absolute c) and rerative(b, c) erfecton mainstemchesapeake Bay segment5 CB3MH and C85MHdeep water dissolvedorygen concentrations,respectiv€ly.

( - haptcr iii TqchnicalJnd l.,lodelrnq(-onride r,.rtions for Scttingthe C,rpLord Allocatron5 1.60

trl '1.,to

1.N co co '1.00 E'F 0.80 zl5i' ET 0.60 oi 93.0.40 ^E6 I'E 0.20

o.00 Maior Ttlbularu Basins

o70 l-t a 0.60 _ao itt - o.so .!f t!o E * o.+o zEiED .EF"""" {ri 9t o.zo 9o 6& o,ro

0.00

Malor Tllbutary Baslns

Figure lll-6. (continued)

('rp ch:t)l.rr iil . Irchtric,tl,rnd l,lctjcllrrq Colrsld{lralior'ls for 5clting thc l-oadAllocai;ons E5TAELISHINGWETLAND INFLUENCEON TIDAL- WATER DISSOLVEDOXYGEN CONCENTRATIONS

In some regionsof the Chesapeaketidal tributariesin the surfacewaters in ttte summer,an oxygen deficit of severalmg/L 02 is typically observed.These regions are found adjacentto extensivetidal wetlands and contain comparativelysmall volumesof tidal waters.Th€ tidal-freshand oligohalineregions of the uppertidal York River is an exampleof relativelysmall volumesof watersfringed by extensive wetlands-Mauaponi (MpNTF, MpNOH) and pammkey(PMKTF. iMKOH; .iu".r. In thes€segments, oxygen demand from tidal wetlandsediments is thoughtto influence surface water dissolved oxygen concentrations.Recent studies estimate wetland sedimentoxygen demandto rangefrom l - 5.3 g Orlm2-day(Neubauer et al. 2000; Cai et al. 1999).In the ChesapeakeBay Watereuality Model, a uniform oxygen demandof 2 g O2/m2-daywas usedas describedin ChapterIL Reeionsof the Bay tidal waterswhere thereare extensivetidar wetrands,but borderJatively large bodies of water, such as in the Tangier Sound have sufficient volume and mixing to mask the oxygendemand ofadjacent wetlandsediments.

WATERQUALITY MODEL RUNS ISOIATING INDIVIDUAL POTLUTANT€FFECTS ON WATERQUATITY Allocations were developedfor nitrogen,phosphorus and sedimentloads for each basin.To achievethe waterquality criteria,some reduction ofeach ofthe threeloads is needed.Within limits, however,the mix of nitrogen,phosphorus and sediment load reductionscan be altered and still achieve attainmeniof the criteria; for example,relatively fewer nitrogen reductionscould be played against relatively more sedimentreductions to achievethe sameresult. To examinethese hade_offs, ,surface an analysis tool called a analysis' was used. While this tool was useful to examinethe tradeoffsbetween reducing nitrogen, phosphorus and sedimentloads, ultimately it will be most usefulfor tributary shategydevelopment, where different load strategiesthat achieve the same level of water quality protection can be examined.

SURFACEANALYSIS PLOTS ln order to examinea particularwater quality parameter,such as dissolvedoxygen, with respectto differentload inputsof nitrogen,phosphorus and sediment,a suriace analysiswas applied. Surface analysisis a statisticalmethod that usesWater euality Model output from multiple scenariosand producesthree-dimensionar plots callei responsesurface plots. A responsesurface plot may be produced.as a concentration of dissolvedoxygen, or as the perc€ntattainment of a dissolvedoxygen criteria for program a particularChesapeake Bay segmentor designateduse over a particular attainmentperiod (i.e., June through September for the segmentCB4MH diep-water designateduse). Response surface plots facilitate the understandingof interactions among nutrient and sedimentloads in the ChesapeakeBay's ecosystemand in

- ch.r Fltcr iii icchnical;nd Mcdcirngt on: 11r:rltion: [or 5ctiln.J thc (ao |oadAllor:"Lronr developingeffective nutrient and sedimentmanagement strategies for improving water quality. Figure III-7 examinesthe influenceofnitrogen andphosphorus loads on the segment CB4MH deep-waterdissolved oxygen concentrations.Note that the nutrientloads are expressedas a portion between0.4 and 1.0 of the 2000 ProgressScenario loads for nitrogen and phosphorus.A 40 percentreduction in nifogen and phosphorus loads,therefore, is representedby the grid positioncorresponding to 0 6 TN and 0'6 TP. The surfaceanalysis estimate of the dissolved oxygen r€sponsem s€gment CB4MH. deepwater showsthat a 40 percentreduction in either nitrogenor phosphorus alone would. improve dissolved oxygen conditions, but reducing both nitrogen and phosphoruswould bring about greater improvements' In using this tool, it is importantto examinethe surfaceresponses with resPectto all the criteria-dissolved oxygen,water clarity and chlorophyll a-and in all regions or designateduses of the ChesapeakeBay and its tidal tributaries,while keepingin mind that the surfaceresponse plots are a statisticalestimate of a seriesof model scenarios,which are also estimatesof Chesapeakewater quality.

CB4MH De€p watel Dlssolved orygen vs. TN and TP loads to ths urhole Bey (io-year ev.rag€). Range o{ TN & TP: ld!% to 40% ol 2qr0 P.Egreas Sc€mdo

5.26

4.50

3.75

Figure lll-7. Surfaceresponie of deep-waterdissolved oxygen concentrations to nitrogenand phosphorusloads in segmentc84Mh.

(,hirpfcr rii ' ll"chni.;rl.rrrd Modclinq Crrn:idi:r.rlions ior 5e11incJth(: C'rp Loiid Al!'rcdti'ns SURFACEANALYSIS UTILITY Despite 'estimate the fact that surfaceanalysis is an ofan estimate'andthe esoteric nature of three-dimensionalregression plots, it remainsa valuabletool. The utility of surfaceanalysis is threefold.First, onecan gain insight from the rerativeresponse of dissolvedoxygen, clarity, SAV,chlorophyli a or any other water quality parameter, to any combinationof nitrogen,phosphorus and sedimentloads. Se;;nd, by interpolating scenarioruns, the surfaceanalysis provides an initial estimateof a waterquality responsewithout the needfor exhaustivegeneration ofnumerous water quality scenarios.Third, and most important,surface analysis enables the tributary teams that are developingdetaited implementation plans to achievethe nuhient and sedimentcap load allocationsto examinepossible tiadeoffs between nltrogen, phos_ phorusand sedimentcao loads.

INFLUENCEOF SEDIMENTON CHESAPEAKE8AY DISSOI-VEDOXYGEN In the Water Quality Model, decreasesin sedimentloads were accompaniedby increasesin water clarity, which resultedin simulatedincreases in shallow-water algae, benthicalgae and SAV.Further examination ofdissolved oxygen responsesro sediment loadsuncovered what initially seemedto be unusualsimulation results. As sediment loads were decreased,deep-water dissolved oxygen concentratton mcreasedslightly. Furtherexamination was necessaryto explainihis response. Shallow watersofthe ChesapeakeBay and its tidal tributariesoccupy a regionat the interface of the land and estuary.Higher sedimentconcentrations are generally otserved in the shallow-waterregions than in deeperopen waters due to local water_ shed inputs, shore erosion and wave resuspensionof sediment.As Figure III-g illustrates, improvedrvater clarity allows moie processingof nutrientsanJ organics in shallow-water regions.Effective interception of nutrientsby benthicalgae, SAV and phytoplankton in shallow,aerobic waters leads to nutrientiiagenesis and lossin sedimentthrough denitrification and phosphorus sequestration. Additional sensitivity runs provided insight into the cascadingeffect of reducing sediment loads in shallow regionsof the ChesapeakeBay on ,iater quality in deef waters(Figures III-9 and III- l0a-b). Figure III_9 showsthe benthicalgae summei biomass for the final calibration.The planarmodel grid showsbenthic algae present in_hany ofthe shallowregions, but rarelyexceeding-2 grams meter2 biomiss. Figure III- l0a is a sensitivityscenario that removes shoreline sediment loads and associated nutrient loads(SENS 146).A relaredsensitivity scenario (SENS 147)removed only the shorelinesedirnent loads, keepingthe nuirients associatedwith the shorelinl sedimentloads unchanged (Figure III- l0b). The pair ofsensitivity scenanos(SENS 146 and 147) demonstratedthat the reducedsediment load was tne causeof the benthicalgae increase.In reality,complete elimination of shorelinesediment loads is extreme and infeasible.I{owever, reducedsediment loads will have a relative eflect on nutrientsand, ultimately, on dissolvedoxygen concentrations.

.h.rptcr iii . fc.h. c.ti,tnd .,lodcling Coosidcrations Ior Sr:ttingthc CnpLoid Allocdtions :t alga€ Shallowwaters are usuallyaerobic, as a aerobic watersi SAV they ar€ localedabove the pycnocline When sedimentis rcducedin shallow N,:*htf"#, waters,light limitation of algaeis rcduced, settling allowingmoro shallow water algal growlh, of algae particularlybenthic algae, and more SAV algae growth.Ovemll more nulrientsare eilher benthic I sequesteredinto lh€ sedimentsof shallov, diffusionto watersor dontrilied. H+ th€ surface

lt algae anaerobicwaters lf shallowwaters have algae sedimont t loads,lh6re is greaterlight limitationof algae,benlhic algae, and SAV Then settling nutrientsno longereffoctilely sequestoaed of algae by proc€ssesin the shallowti/aters, fuel algalgrowth in the deeperwaters of the -a a Bay wher€ the presence of a pycnocline oo t rflru*-eo.f;lX";3fr3", resultsin low to no dissolvodoxygen oecay welersand ammoniaand Phosphate flux out of the sediment-

qualityand livingresources Figure lll-g. lllustrationof the inJluencesediment load has on shallow-waterwater

Fiqurell|.9'Fina|ca|ibrationsummerbiomassofbenthica|gae'Theunitsareingrams biJmassmeter-2.

<-haptcr iii ' tc.hIica]and l"4odclrrr';consi(ler.ltons firr Settin!l the cJp lo'd Allocdtrons 2.5

I c5 c.0a

Figure lll-10a. Sensitivityscenario of benthicalgae summer biomass with no shoreline sediment or associatednutrient loads.The units are in grams biomassmeterr.

Sensirivity flg.ure lll;19b s(enarioof benthicalgae summer biomass with no shoreline seorment,bul a55o

cililpterr iii . Icchnic.tl rnd N4o.lclingCon:icleratictns for Scttinq thc CJpLc.rd Alt,J,atro|rs of A modeling study of the Delawareinland bays demonstratedthe importance benthic algae on sedimentdiagenesis in shallow waters Figure III-11 shows the simulatedeffect ofthe presenceand absence ofbenthic algaeon nutrientand oxygen (C. Cerco,unpublished data). The presenceofbenthic algaeresults in greatervarla- tion in nutrient and oxygen tlux from the sediment(positive values out of the sediment,negative values into the seriiment)but an overallnet decreaseofdissolved inorganicphosphorus and dissolvedinorganic nitrogen flux out of the sediments' in Voaet nniings were substantiatedby observedflux of oxygen and nutrients Delaware tnland Bay sediments(S. Seitzinger,unpublished data), i e'' shallow greater waters with sufficient light for the growth of benthic algae demonstrated retentionof nutrients. In addition,researchers have shown the role of improvedclarity on decreasedlevel of nutrients.Using a STELLA modelinganalysis' Kemp et al' (1994)explained that the interceptionof nutrientsby "enhancedsuspension feeding in the shallowwaters ofthe Bay ... etTectgreater improvem€nts for bottomoxygen than comparable action at deep sites".The interceptionof nutrientsand increasednutrient processingwas furthei examinedby Newell et al. (2002),who describedthe potentialfor greater denitrification and sequesteringof nutrients in aerobic shallow-watersediment While these researchersspecitically examinedshallow-water oyster beds as the agentfor greaterinterception and processingof nutrientsin aerobicshallow waters'

WithAloae - No Algee-

DissolvedOrygen Flux PhosphateFlux b15

(5o -5 -10

AmmoniumFlux NitrateFlux b rso hzs > 100 iu 275 225 'n 50 C5 ,so -0 -100

YEARS YEARS

Figure ll-11. DelawareInland Bay study showing relative range of nutrientand dissolved ox"ygenflux resultinglrom the presenceor absenceof benthicalgae'

(ih.rf)t.r iii - ftchni(al,rnd l',1od1rlincJ Conridcratlons for Scttii'qthc C'rpLcad Allocdtlons decredsed light attenuationwas the principal factor in increasingnutrient intercep- tron in the model simulations. Estimates ofthe influencethat sediment loads, particularly to shallowwaters, have on dissolved oxygen indicatean interestingsynergy among nutrienVsediment loads and living resources,but care should be taken not to over-interpretthese results.The current sedimentsimulation is the mostrefined model estimate ofsediment loads, fate and effects,and considerable time wasspent with the calibration.However, shoreline loads wereapproximated everywhere as a daily baywideaverage input, and sediment transport and wave resuspensionwere not simulated.overall the influenceof sediment loads on dissolvedoxygen was fbund to be reasonableand conslstentwith cunent understandingof shallow-waterprocesses, but also provecrsright in its errect. A reduction of 20 percentof the loadsfrom shorelineerosion and resuspensionhad the equivalentreduction in deepwater dissolved oxygen as about a five million pound reduction in nitrogen.A 2003review by the ChesapeakeBay program,sScientific and Technical .;. Advisory Committee(STAC) found that the . . techanisms linking shoreline erosionreduction to improvementsin deep-waterdissolved oxygen through rmprovedwatei clarity and increasedshallow_water microphytobenthos productiJn were plausible, but unproven"(STAC 2003).one concemthe srAC revrewraised is the inability of the model structureand mechanismsto scour benthic algae,which may, after ftansportof organicsto deep water, contribute,to deep_wareroxygen demand. The WaterQuality Model is now beingrefined with a sedimenttransport simulation, refined spatialand temporalinputs of shorelineerosion loads and a srmulationof wave resuspension. with enhancedfeedbacks between SAV and resuspendedsedi- ment. The influenceof sedimentload reductionson deep-waterdissolved oxygen concentrations will be reexaminedduring the reevaluationof the nutrient and sediment allocations,which is plannedfor 2007.

ESTAALISHINGAND ASSESSING NEW SAV RESTORATIONGOALS During the developmentofthe waterclarity criteria,the shallow-waterdesignated use and.the associatedsediment cap loadallocations, the partnersag:eed to the alignment of the Chesapeake 2000commitment to establishinga new SAV restoratronsoal with the commitment .,achieve to reducingsediment loads to the wBterquality clnditions that protect living resources."Chesapeake 2000 calledlor a recommitmentto the long-standingI14,000-acre SAV goal and further called for more ambitious.,sAV restorationgoals andstrategies to reflecthistoric abundance, measured as acreage and density from the 1930sro the present-including the specificlevels of water clarity needed(Chesapeate Executive Council 2000). Ultimately the SAV goal established to meetthe Chesapeake2000 commitment Was a 185,000-acre restorationgoal, specifiedas baywide,iributary basin,and segment_ specific restoration goals (Appendix A; SecretaryTayloe Murphy 2003j. The sedimentload allocationis closelyaligned to this goal.

chitPkrr iii - fr:<.hr:ical ( anclMorleli|rq onriclcr,rti0nsfor -Sctiin.lthe C,rpLo.rfJ /illo.,)tions DEVELOPINGTHE 18s,OOO-ACRE sAV RESTORATIONGOAL The ChesapeakeBay Programhas long committedto protectingand restoringSAV' ln 2001,thire were 85,415acres of SAV in the ChesapeakeBay and its tributaries' The total potentialshallow-water habitat availablefor SAV in the ChesapeakeBay out to 2-metersis 640,000acres. SAV never covers 100 percent of the available habitat,but on averagecovers approximately 35 percentof it (U'S' EPA 2003b) On April 15, 2003, the ChesapeakeBay Program'sPrincipals' Staff Committeeand representativesof the headwaterstates approved the new Bay grassrestoration goal of ttS,OOOacres by 2010.The partnerstates ofthe Bay Programhave adoptedthe new goal, meeting.theChesapeake 2000 commitmentto: *By 2002,revise SAV restoration goals und strategiesto rellect hisloric obunrlarr", measuredas lcreage and densityIrom lhe 1930slo the present. The revised goals will include specific levels of water clarity lhal are to be met in 2010 Strategiesto achieve these goals will utltlress specific levels rtf water clarity, water quality and boltom di-,;turbance)' The following principles guided the developmentof the recommendednew SAV goal: . Use the bestavailable data; . Establisha direct link betweenthe new goal and the new water quality criteria; . Recognizethat sAV shouldnot be expectedto cover all availableshallow-water habitat; . Areas cxpectedto contribute to the goal should only include those that have demonstratedsome minimal level of abundanceor persistencein the past;and . Providesegment-specific acreage goals for useby the tributary stmtegyteams' The SAV abundanceand tlistribution record includes interpretedhistorical aerial photographytiorn the late 1930sto the 1960s,as well as the annualbaywide aerial ,r,ru"i Outo-to* 1978and 1984-2000.The singlebest year of SAV growthobserved in eachCBP segmentfrom the entirerecord ofaerial photographs(1938-2000) is the best availabledata on SAV occurence over the long tcrm' Thesesame data were used to define, within each ChesapeakeBay segment,the depth to which the shallow-waterBay grassdesignated use should be considered That depth is the depth at which water clarity criteria would apply in the contextof state maximum 'application water quality standards,and is, theretbre,referred to as the depth' for eachsegment (U.S. EPA 2003b).Table tll-l containsthe derivedsegment-specilic applicationdepths. As the first stepto settingthe SAV goal acteageout to the specificapplication depth was determinedthrough bathymetrydata and aerial photographsused to slice the single-best-yearSAV acreagein eachsegment into threedcpth zones:G 0'5 meters' 0.5 1.0 metersand l-2 meters;antl aerialphotographs used to determinethe depth

( lr,rpl.rr lii - irr.flncal antl I!1o11llirrr;Coi-t':idt:rations for Settin'ltlre C'rpLo'rd AL ocatLons to which SAV grew in eachsegment with eithera minimum abundanceor minimum persistence.

Next, the SAV goal for a segmentis the portion of the single_best_yearacreage that lhlls within this determineddepth range, which, ih hrn, was establishedas follows: In all segments,the 0 0.5 meter depth interval will be designatedfor shallow-waterBay grassuse. In addition,the shallow_waterBay grassuse will be designatedfor deeperdepths within a segmentifeither: . The single-best-yearSAV distributioncovered at least20 Dercentofthe potentialhabitat in a deeperdepth zone; or . The single-best-yearSAV coveredat least l0 percentof the potential habitatin the segment-depthinterval, and at leastthree of the four five- yeauperiods of the record ( 197g_2000)show at least l0 percentSAV coverageof potentialhabitat in the segment_depthinterval.

sAV restorationgoals havebeen estabrished in a mannerconsistent with the sinsle- best-yearmethod used to determinethe applicationdepths. Within eachsegment,-the 2010 restorationgoal for designateduse attainment purposes is equalto the acreage the of single bestyear on recordwithin the r.g-"ni,, applicationdepth (U.S. EpA 2003b).These segment-specific SAV restorationgoals are listed in TableIII-1. New SAV acreagegoals have been establishedon a segment_specificbasis, a baywide basisand, betweenthose two, a major tributary basin_speclficbasis (e.g.,potomac River; seeTable III-2). The new baywideSAV goal, 185,000acres, is the sum ofacreagetargets for eachof the 78 ChesapeakeBay segmentsbased on the single-best_yearacreage on recordfbr eachsegment. The achievementof the baywide goal, as well as the local tributary basinand segment-specificrestoration goals, will be basedon the single-best-year SAV acreagewithin the most recentthree-year record of survey results(U.S. EpA 20O3a). The. ChesapeakeBay Programpartners reached the foltowing agreementson the implementationof lhe SAV restorationgoals:

l The tidal statesof Delaware,Maryland and Virginia and the District of Columbia will adoptnumerical water clarity criteria and considerthe adootionofthe SAV acreagerestoration goals for eachChesapeake Bay program segmentinto their WaterQuality Standards.

2. The SAV acreagerestoration goals will be used as the pnmary metric in the developmentand implementationof the triburarysfrategies with regardto sedimentcontrols. lfthe SAV acreagerestoration goal is achievedin a given segmenq if and the statewater quality standardsallow, that segmentwill be consideredas havingachieved the shallow-waterbay gtassdesignated use evenif the sediment loadingcaps were not met. 3. Virginia and Marylandwill developcomprehensive SAV restorationstratesies to meet the new SAV restorationsoal.

( h.tpifr iii . ;rncl firchnt(.tl ivlodr:lingConriclcrations for S..ttinqthe Cap L.l,td Allo(ations Iable lll-1.The new ChesapeakeBay sAV acreage goal and currentSAV acreages by ChesapeakeBay Program segment. 2001sAv sAv ChesapeakeB&y Program Shallo\fl-waterSAV Acreage Out to Restoratlon Name Application Depth Applicttion Depth Goal Nonhem t-'pp".Ctt"tap."t. euy O.S 203 ]9? g+r Uii"rEnt e"y O.S t "rctt"sap""t" Middle Central tt2 Lower Ccntral WestemLower 7t5 980 EastemLower 9.168 Mouth of the 0.5 8 6 Bush River 0.5 3 158

Middle River 838 Back River 0.5 - PatapscoRiv€r I 298z'o * la"gottty niu€I i S+S SevemRiver I 120 329 South Riv€r 459 RhodeRiver 0.5 48 WestRiver 0.5 Patuxent River WestemBranch 0.5 Middle PatuxentRiver Lower PatuxeDtRiYer PotomacRiver 2 AnacostiaRiver 0.5

MattawomanCrcek Middle PobomacRrver 3.070 3.721 Lower PotomacRiver I t73 River 0.5 66 20 Middle River 0.5 0 River 4',78 80 Corrotoman River 189 516 PiankatankRiver 519 River 0.5 75 Lower River 0.5 0 River 0.5 140 155 0.5 0 River 't'7 Middle York River 0.5 6 Lower York River 801 2 t5 Jam€sRiver 0.5 95 I River 0.5 319 Middlc JamesRiver 0.5 7 co ti\ued

.h:rpL('r iii . lochnicalanC l',/cdelingCon5iCcrtlions lor Settirr-lthc Cdp LoadAllocations 200tsAv Chesapeake sAv Bay Prograrn Shallow-waaerSAV AcreageOut to Restoration SegmentName Goal ChickahominyRivcr 0.5 268 348 Lower JamesRiver Mouthof theJames River 232 604 WestemBranch ElizabethRiver SouthemBranch Elizabeth River EastemBrarrch ElizabethRiver 0 LafayctteRiver Mouthf,r^,.]L ofthe^f.L- ElizabethRivcr *0 l.ynnhavenRiver 69

C&D Canal 0.5 BohcmiaRiver 0.5 354 97 Elk River 0J4 SassafrasRiver 1.169 764 Upper Ch€ste! River Middle Chcster River 0,5 63 Lower ChesterRiver 108 River 0 Middle Riyer 0.5 63 Lower River 499 Mouth of the 2 Liule River 2 River 2 0.5 193 Nanticoke Rivcr 0 Middle NaDticokeRiver 0.5 Lower NanricokcRivcr 0,5 WicomicoRivcr 0.5 Manokin River AnnemessexRiver

Lower PocomokeRiver

+7,561 acresof SAV not includedin the suffey due to heightenedsecurity

85,419 iDenotes no dataavailable or no SAV present_ SourceiU.S. EPA 2003b.

cha p t.ir iii - ftr:ltnic;l and i\,lcdcling Consicie,rJtion,fcr !.-ttrng thc Cdp Lo,rdAllocations Tablelll-2. Chesapeake Bay SAV restoration WATERCLARIW AND SAV goalsby majortributary basin. The \rater quality criteria distin- SAV Restoration guish two types of SA\ Jurisdiction-Basin Goal (acres) communitieswith resPectto light Susquehanna 12,856 requirements(Batiuk et al. 2000; 2003a).The tidal-fiesh EastemShore - MD 76,193 U.S. EPA and oligohaline communities are WestemShore - MD 5,651 €stimatedto require greaterthan 13 t,420 Patux€nt percent light-through-water while Potomac 19,450 the more light-sensitive SAV Rappahannock t2;198 communitiesof the mesohalineand York 21,823 polyhaline areasare estimatedto James 3,483 require 22 percent light-through- water.These light requirementscan EastemShore - VA 31,215 as light attenua- 'l'() also be expressed r.\ r. HJ.r,894 tion (variouslysymbolized as Ka or K"), which representsthe rate of light lost through the water column

Rcpreseitingthe equivalentlight needsfor the tidal-fresh'ioligohaline and the meso- light haline/polyh--alinecommunities, Figure III-12 graphs the tradeoffsbetween a attenu;tio; and depth.Light attenuationis a rate of light lost by passagethrough water column, either by scatteringthrough sediment,absorption by algal chlorophyll, or loss through absorption by dissolved organic material or water' For iidul-fr"rh o, oligohaiineSAV communities,a K6 of 2.0 meter-lis equivalentto the 13 percent lighi+hrough-waterlight requirementat a l-meter. depth' As depth to inc.Lasesthe light path, less light attenuation(greater water clarity) is required achievethe .uri" 1i p".""nt light-through-water,so that 7t a2 meterdepth' light attenuationof no lessthan I meterl is requiredto supportSAV' At decreaseddepths more light attenuationis allowablefor SAV,so that at 0 5 metersdepth, a Ka of4 0 meterl is still supportiveof SAV growth. To achieve the water clarity levels to support SAV, reductions in light attenuation by any of the various components(sediment' algae or color) may achievethe light requirementssupportive of SAY but for much of the Bay's tidal waters,reductions .ot"ly in out i"ni. and ultimately chlorophyll and epiphyticgrowth, are insufficient' the A li;ht attenuationmodel developedby Gallegos(2001) providesinsight into variJus componentsof light attenuation(see http://www'chesapeakebayneVcims/ index.htmunder "Factors Conhibuting to Water-ColumnLight Att€nuation:A Diag- period nostic Tool"). This modelis applicableto any monitoringstation data for any from of time. Figure III- 13 representsestimated seasonal average light attenuation the variouscomponents with color and attenuationdue to water combinedat the to monitoring station EE3 2 in the Tangier Sound for the SAV seasonof April on October.At a l-metcr depthplotted here, only an estimatedI yearin l0 provides' a seasonalaverage Uasis, the lignt requiredfor a mesohalineSAV community of22 percentlight-through-water (Kd of 1.5meter-l ). Reductionsin light attenuationdue to dissolvedorganic material and the baselight 'K,l they attenuationrate of waterare heredepicted as color' and arenot possibleas

Lc'rdAllo'rlion5 chnpt.r iii . Tc.hnic.lland i'.4cdctingCcnsidcralions for Settlngihe Crp AppllcatlonDepth w a ovyabtelq

0.7 r.9 1.1 1.3 AppllcatlonDopth (metors)

Figure lll-12. Plotsof equivalent 13 percert light_through_waterfor tidat_fresh(TD andporvha,ine(pH) oligohaline l?l'#;nHl':::l^'.'"'^:-".::*'l"i,ti;d-*#l';'iiiJi'iii"""r"'r""dsAVcommunities atdepths between o.:1na z.o i"t",ri;;;;r#;ilii:ilffi;*'H1i:i"li:1. ".

2.50

e 2.oo 5 ro 1.50

1.00

0.50

0.00 1986 1987 1988 '1993 1989 | 994 Figure lll-'13.Estimated averaoe co ,.:;;"";,tt*t:,"H ::i!;ll;;rjil:ffi ffi Lffgi.Tiltl1,:f i Jft j[;[l11.TT$fl?ru, source: Chesapeak€Bay water quality output httpy,tvww.chesapeakebay.net.

(:hapL.r 'ii ' Tccirniclr ;nd ir,40rlcrinq consicerationl for 5cltrng the c,rp Lond AJlocJtions reducing algal nutrients will are natural conditions. Managementreductions in but in TangierSound' as reducelight attenuationfiom phytoplanktonand epiphytes' in nutrientsare estimated to be ;;;il;;Gt ;rtne eav's tidat waters'reductioni to supportSAV growth. inrum"i"nito improvewater clarity to levelsnecessary

SEDIMENT LOADS: LOCAL EFFECTS loads and allocations Sedimentloads and allocationsare different from nutrient that sedimentsare more pr*io".ty aon" Uy the ChesapeakeBay Programpartners^in the Bay's tidal waters'as iocar in their aTect.Nutrient loadsaffect larger€gions of oi."u,."oabove.sedimentloadsinthiswaterqualitymodelsimulationhavea simulatedsediment transport' iieiJt*tiite .* than organicmaterial and' without do not resuspendfrom the bottom' behaviorthrough the use FigureIII- 14 illustratesthe local effect of sedimentmodel waterquality model cell (#1720) oi1' .i-utnt"a sedimentload in a particularsurface s€dimentftacer concentra- in the EastemBay of the ChesapeakeBay The simulated with the concentration tion was highestin the cell into which G tracerwas loaded' cells from the cell into which ouicttv aro"ppinein adjacentcells At a distanceof l0 no longerdetectable' il;;";;: i";J.d (about l0 kilometers),the lracerwas researchfrndings of sediment These findings are consistentwith monitoring and cunent lack of a sediment behavior, with ohe lmportant di{ference With the suspendedsedirnent reaches transportmodel in the water quality simulation'once

2.00

.9 €^r.o 9A

091 EE E-t.- UPBaYfvom Cell 1720 t ai )+

0-5{)

1710 17?Io l73O 1740 Wator Ouallly Modol Coll Numbsro

loadedto a singleshoreline Figure lll-14. Lo

ior Settingthc cdp l.oadAllocatlons ch.rl)t.rr iii ' tcchnicalancl NlodeJlnq Cofsi(lel'liions the bottom ofthe water column and is incorporatedinto the bottom sediments,it is lost ftom the system,as no resuspensionis simulated.Work is underway to incor_ porate sediment transport into the simulation. A complete descnption of the Water eualiry Model's sediments;-utution U" for.rndin Cerco and"h::ip"f:^!iI Noel (2003). "un

CALIBRATING THEWATER QUAttry MODELFOR CLARIry To supportthe development ofthe sedimentcap load allocation,much attention given was to calibrating various componentsof light attenuationin the Water euality Model. In the absenceofa full sedimenttransp-ort model, calibration entalled recon- w*:rshedrr,ioder (ph";;4rj;;li-"nt inputroads ::i:l-_i:,*-1y_:T.:!:1k".puywrrnmonrroflng program estimates ofsuspendedsediment concentraiions by region_ ally adjusting the sediment settling rates. nurtner oaiu.tm"oi of the sediment conc€ntrations,particuldrly useful for the calibrationof sedimentin bottom waters and in turbidity maximum zones,used differential ,"ttting ,ui", in flr" water column and in the sedimentbed. The settlingrate of sedimentin tt" *uie, was set at a higherrate thanthat of sediment "orumn bed incorporationto fu"toi in the potentialfor resuspensionofaccumulated sediment in the bottom model cells.Figure III-15 is an exan_pleof the resulting calibration in upper ChesapeafteBay mainstemsegment C^B_2OHsurface waters.and is representativeofa sinlle monitoring stationcalibra_ tlon rn comparisonwith model estimatesof the few associatedmodel cells at the monitoringstation C82.2 location.Full calibration,".utt. foi ..ai_"nt, chlorophyll and light attenuationare documentedin Cerco and f.r""i iZoOii further documentedin http://www.chesapeakebay.net/modsc.htm. ""a

:E[tst34 0N i\tEWGRil] LightExtinction Llght ExtinctionC82.2 Surface

e o =

3 2 1

0 YeaIs

Figure llt- 15,, Time series plot of modelsimulated light attenuation(solid line) and ,'lnremonitorin{ model- surface,lt.:::rj1"?::n*. j.::*'l^t_:j statio",cer.i, ;oipar"a to a sinere modetcelt. rhe time series " r-,n t"ii"f i;;i;i.e."iri#ril: ""t*a, ch.rplcr iii . Technical;ncl tu1r_.r1cli,rr; Con5r(lcr,lironsf'r Sctttnrjthc {,Jp loa. rlilr:catio.s of the long-term While calibrationoflight attenuationwas nece!sarilyat the location deepelwaters and away -""i *i.g stations,tiese stationsare tlpically locatedin at the interfaceof the from shall-ow-waterSAV habitats'Shaliow regions,located 'point sedimentloads from watershedand the tidal Bay' areat the of discharge'of all and generally the adjacentwatershed, shore erosion and shallow-waterresuspension monitoring statlons' iuu" L.t clarity than that found in the traditionaldeep-water for the shallows Figure III-16 showsthe relativedifference of K6 model estimates estimatesthat the and deepwaters ofthe ChesapeakeBay' Typically,the simulation

L.grnd Kd (1/m) f.--] o.mm- o.som []osomr-,.som - ffi r.:ooorz.smo I z.sooor' :.somo

attenuation(Kd) :ioure llt-I 6- ChesapeakeBay water QualityModel estimated light the deeperwaters ol the ,ti*"ing g,""t". fightattenuation in the shaliowsthan in o{ sedimentloads lh*t"oi"-t" aay arid its tidal t.ibutariesdue to the local influence from the adiacentwatershed and shoreline(units are meter-')'

Scttingthe CJpLc'ld Allocdticns r haptcr iii - iechnicalrncl MoclelinqConsidcration! fur shallowshave an attenuation rate fwo times greaterthan that of deeperwaters, a finding consistentwith monitoringprogram obsewations. To addressthe differencebetween light attenuationestimates in shallow and deep waters, the monitoring program initiated a rong-term shallow-watermonitorin! assessmentin 2003_With information from new and existing monitoring assess_ mentsand researchinto sedimentprocesses and transport,the Watereualit Model will be refined with an explicit sedimentrransport simuLtion by 2007, in time to supportthe reevaluationof the nutrientand sedimentallocations.

RELATINGsAV BIOMASSTO ACREAGE SAV abundancehas been assessed by aerial surveysfrom l9g4_2000,usually flown onceannually at the time of€stimatedpeak abunjance(Moore et al. 2000).Area is relatedto abundanceof SAV throughdensity and biomass,that is, the areaof SAV coverageincreases as either densitydeceases or biomassincreases, all elsebeing the same.Fudher, changes in areamay not be linear with changesin biomass.For these reasons,biomass has been describedas a bettermeasure ofibundance thanarea, and biomassis the key SAV metric simulated by the ChesapeakeBay Waier euality Model. On the other hand, aerial llu*"y. of SAV u."u i." and the public goal ofSAV restorationto an establishedacreage is a straightforwardmessage"ost_"tte"tive, to communicateto the public. For thesereasons alone-the aerial surveys of SAV have been,and will continue to be,the basisfor abundanceestimates ofSAV in the chesapeake Bay, augmentedby associatedestimates of SAV biomass. The model structureof simulating ,unit a plant, of SAV withrn the larger water quality contextof the Water euality Model (Cerco et al. 2002; Cercoand Moore 2001) generatesbiomass estimatesof SlV. OUvioustn,n" nrr, .r"p in relating the sAV restorationgoal and the sedimentcap roadalrocations estrmateo in the model is the reconciliationof the acreageand biomassestimates. Fundamental to this reconciliationis the work done by Moore et al. (2000).Buiiding on this approach, the-chesapeake Bay programpartners usedthe watei euarity Model estimatesof SAV biomassto derive SAV acreageestimetes (Cerco ei al. ZbO:;_fne essenceof using the model estimates of biomassrelies on the .i-pl urrurnptronthat SAV densitydoes not changein the model scenarios.Then model estimatesof SAV area can be determinedby the simplerelationship: SAVAcres = (SAVbiomass sc€nario/gAvbiomass calibration) * acres SAV observed | 9g5_1994 As the calibrationrelates the SAV biomassto estimatedSAV areaover the l0_year periodof 1985-1994, and further as the scenariosrelate a relativechange in SAV due to changesin nutrient or sedimentloads, the relationshipabove provides a reason_ ableestimate ofSAV areafor any scenario- SAV biomassraries over the,g.rowing season as shown in figures III_17 through III- 19.Aerial estimatesof SAv abunrlanceare taken once during'the year at about the time of peak biomass, generallyin the rate,un,.", r"'. otigoi-ulineand mesohaline regions,and in the latespring or earlysummer for thepolyhaiine regions (Moore et al. 2000). To coordinate the observedpeak abundanceestimates with model_simulated estimatesof SAV,July averaged simulatedSAV biomasswas used throrighout, except r h.rptcr iii . ii:chnic,tiand itloclclilg Con:ider.ltronsfor Sr,ttrngthe CJpIond Allcc.lttons W

fieshwatercommunny O observ€d _- modslad(cBl' run 178) 2@

1&)

160

140 I 1n

100 I 80 I ti I

12 1234 567 910 11 monlh

percentol com- lll-'l7. Modeled(mean lsolid line] and interval encompassing-gs Figure interval puiations line])and observed (mean [dotl and95 percentconfidence [dashed biomass tinetfrrough dotl) JreshwatersAV community (above ground shoot ivertical susquehanna olt"rv",ion;trom Mooreet al. (2000)Model iimulation from the !'ifri. '1998 Model' iLii (s"g."nt cerrF)using the 10.000-cell versionof theWater Qualitv source:cerco et al.2002.

monthly peak for tidal-freshregions, which use a Septemberaveraged biomass' The biomass' averageis typicJly about thee times higher than the annual average two factors In relatingthe SAV restorationgoal to the sedimentcap load allocations' estimateswill be nee

thc CJpLoad Allocatrons ch.rptcr iii - fr:r:hnical.lnd Modr:lrngLon:idcritions tor 5etting rupPracommunity at obsgrwd model€d(EEl, run 1 Z8l

Figurettl-18 Modeled(mean lsolidline] and interval encompassing 95 percent o, computations linel) [dashed andobserved (mean Idot] and g5 perceitconfidence interval lv€nicattine throush dott) rnesohatinesAV ;;;;d A;;;;":'"uiu" qrouna,hoot bromassonly), Observations from Mooreet al. (2O0Oiyeisl 5;rnrlationfrom Eastern Bayusing the 10,000-cell l99gversion of theChesapeake i"V W"i", ti""fityUra"f. Source:Cerco et al.2002.

rivers,rhough pad l*:{t": of CBITR were assignetlto rhe EastemShore Mary- land,/Delawarebasin (Figure III-20). Model estimatesof the SAV responseunder different managemenrscenanos were estimatedwith two metrics, an SAV single-best_yearestimatl and an SAV running- three-year,single-best-year mean estimate.The single_best-yearestimate is an estimat€of the highestannual biomass .SAV throughiut the simulatedhydrology period of the 1985-1994. The single_best_yearestim-ate most closely resemblesthe new sAV restoration,in that the highestannual biomass is usedfor the entire simu_ la^tionperiod. The SAV running-three-year, single_best-yearmean estimate is a mean of the best year estimatesof the eight thrle_year periods tfrat the 19g5-1994 simulationcan be parsedlnto lllgs_t9t7, l936:198S,1987-1989, etc..) The SAV running-three-year,single-best-year meanan

( lr"rt)t.rriii - lirchnr(,il (_on.,idcrations .lrd llorlcitnq k)rScttrnq fhe C.to to.tci Ailocattons zostaracommunity O obsarved - modsled(wEl, run178)

-l

67 89to 11 12 molilh

FioureIl|.19.Mode|ed(mean[so|id|inelandinterva|encompassing95percentol linel)ani observeJ(mean [dotl and95 percentconfidence intewal ."".p*"ii""i fa"trt"J ground bromass ih;;gh dotl) polvhalinesAV communitv (zosteta above shoot J;;iJl;"; fromthe Mobjack gay onty).OUr".utioni trom Moore et al (2000) Modelsimulation of chesapeakeBay fseimentNaOgpH, lormerly WE4) using the 10,000-cell1998 version the WaierQuality Model. source:cerco et al. 2002.

Flats in the upper responseis representcdas the SAV rcsponseofthe Susquehanna tidal-freshChesaPeake BaY' Jamesrivers did not Underall scenarios,the lower Rappahannockand the tidal-liesh SAV areain response meet the C2K SAV acreagerestoration goal, as the simulated of SAV historic to the scenarioload reductions*u, .*h less than the estimates goal The Patuxcnt u"r"ug" tfrot formsthe basisofthe 185,000-acreSAV restoration an initial drop in SAV and iappahannocktidal-t'resh €stimates of SAV area show both casesthis counter- acreageLetween the 2000 Progressand Tier 3 scenarios'In an increasein light intuiti'veresponse is due to a decreasein s€dimentloads causing and a simulatedpoorer throughthe water column,resulting in greateralgal biomass SAV responseto habita-tfor SAV Further reductionspast Tier 3 show increasing greaterthan the mean' tlecreasingloads. The standarddeviation is in many cases the high particularl in regionsof the Bay whcre SAV acreageis sparse'indicatiflg variability in year'to-yearSAV rrea.

( !cLtlnqLhr: Cap load Allocdtlor'rs .lr.lFrtrr rii - ft

Figure lll-20. SAVregions associated with the ma.iorChesapeake Bay irtb,r*y b"rl"s'

SPATIAL ANALYSISOF EFFECTIVESHORELINE LOAD REDUCTIONS sedimentreductions from the watershedalone are estimated to be insufrcientfor fu' S,*,1*.:"t" to the 1g5,000-acre SAV restorationgoal. Additional ."du"tions ,o shorellneloads including shorelineerosion loads and resuspension were simulateJ15r key scenarios.In tables III-3 andIII-4, rwo scenanosare simurated with an additionar chapLerii; - []chnical.rnd Mo{Jclinq Con5idcraiionsforSetting thL, L,rp Lc.rd Allocations Tab|et||-].Sing|e-best-yearestlmateofsAVareaunderkeymanagementscenarios'M€etscBPgoa|= 2000 goal = the new sAV the original 1992 sAV l'"rtor"tionlo"l oi t t l,ooo acres' Meets Chesapeake restorationgoal o{ 185,000acres. SAV Acretge

'Iier Goal Tier 3 3 +20'h Scenario 175 CBP Goal CzK 24400 7620 12856 Susquehanna t3l7l 20400 20400 641E 3710 5652 WestemShore MD 4522 49't8 6453 t98 l4 PatuxentTF t42 85 88 '145 712 451 t420 PatuxentLower 209 276 12842 73't4 5438 PotomacTF 6278 8768 t26t8 9751 s244 r4017 Potomac Lower 76ll 7976 too'l2 0 20 TF 48 45 45 3527 53'76 L?778 RappahannockLower 2927 3201 3s39 4851 23r YorkTF t734 2t73 4298 20408 1834't 2t592 York Lower 15995 17848 20't26 552 t944 JamesTF t36 JIJ 580 746 983 838 441 1593 JamesLower o)o '77',l06 54475 42280 Eastem Shore MD/DE 33"t65 40970 548r9 28518 228r8 29'102 EastemShor€ VA zl28r 22'747 2626',7 163601 113675 184954 l'o1^L 108475 130512 l6r6t3

-' Scenario175 nutrientand sedimett cap load allocations goal E s""nntio 175 meetsoriginal 1992cBP SAv restoration (C2K) sAv restoration fl scenario 175 mectsChesapeake 2'u0 Soal

reduce 20 perccntreduction in the baseshoreline loads representing BMPs' which ChesapeakeBay, shoielineerosion or sedimentresuspensionl. In manyregions ofthe reduction particularlythose with extensiveshorelines, the 20 percentshoreline load and in SAV' iesulted in a significant improvement in shallow-water wat'erclarity analysis was To further refine where the shorelineloads should be applied, an the adjacent conducted to determine where any historical sAV occurred and map shorelinereduc- shoreline.The identifiedshoreline was consideredto be that where buffer tionswould be effectivefor improvingSAV habitat'An arbitrary0'5-kilometer protection of SAV was extendedalong the shorelinebeyond the SAV areasas a further and the habitat. The combined shoreline adjacent to any historical SAV occurrence 'effective O.5-kilometerbuffer of shorelinewas calledthe shoreline'' from a low of 16 The percentof effective shorelinevaried from basin to basin ranging PotomacRiver perc;nt in the JamesRiver to an effective shorelineof 73 percentin the

loadsmay bo ffiI i,ru. to thepaftners that a 20perccnt reduction in bas€shoteline n.".ent€d not availableto reach a i""""Joi"*", t'echnicalfcasibility Howwer, suiicient information was definitive conclusionat that time

q,ln51'1".rt (ap LoadAllotations ,::h.rptcr iii - fcchnicaland Modeling onsfor Srlttinqthe c.l a.l E -\o^ I Or a{ 1.. a- Q F. o\ ct r>=0J 4

N t\ t\ r!.. (J a-

E---o hol -Vo t (uo t- c- !r\ + i.] \o o e.l ..i l!Q c+c,P 3S q) (uo "i et) a> "o in dt 9 o\ F oa + lE-. F o.l o\ q \o a.l ors oi -c- s4l .i6 .=l oto 'Ec ?l .=l c., o\ cr \o c\ =l at :i JI U) r.i !ni (.) | 'F> .. I . .og vl< FI FI i;l 'r= (t 9 r'.r 2l AI oi .-l 9E< t 6 g. o. \o a- o< \o [

0.80

0.70

0.60

0,50

0.40

0.30

0.20

0.10

0.00 West Shore Polomac York ESMD/DE ' Patuxent Rappahannock Jamss ESVA

Bayba5|n5. Figure |||.? 1. Estimatedeffe(tive shore|inefor the major chesapeake

basins' Fiqure lll-22. EJfectiveshoreline regions oJ the James,York and lowerRappahannock

lhc C;p Loadi\llocations ch.rptcr iii . i:chnical,rncl Modcling Cofsidcrations {or 5etting MONITORINGAPPROACH

Bay Programpartners ]l,Chesaneake agreedto measurethe achievementof the C"al.atlhe segme_ntscale based :,:^"^i.:11:" on rhe singlebesr year of a running rnree-yearassessment to accountfor year-to-yearfluctuations in water clarity due to changinghydrotogy and loads (u.s, EpA z-oo:ay.ro ensureconsrstency between derive the cap toad T:,*: T:d.l: allocationsand measureathinme;t, modet_ slmuratedsAV acreages were assessedusing the single best year of a running three-yearassessment period. The model estimatesfroir th" l0-y"* averageest! r.nat:w.ere matched with running three_yearsingle_best_year estimates and formed the basisof the final model estimatesof SAV underthe iifferent scenanoassump- tronsas shownin tablesIII_3 and lll-4.

SEDIMENTCAP LOAD ALTOCATION PRINCIPLES The principles applied in deveropingth6 sedimentcap load a ocahonswere as follows:

l. SAV habitat and the setiiment allocationare linked and the primary reasonfor reducing sedimentloads is to providesuitable habitat tor SnV] 2. Sedimentimpacts, unlike thoseofnutrients, are local in their influence;and 3. The analysisand effects of nu.rientson dissolvedoxygen is well developedand understood,but the analysis of sedimentloads and wlter quality effects is in- complete.

With theseprincipals in mind, program the ChesapeakeBay partnersagreed to include SAV goalsinto waterquality lhe standards.The locatn-uture oftt. of sediment roaosrs reltectedin the assignment-ofSAV goalsto eachChesapeake "ftU"tsBay program segment.[t wasdecided that either the SAV acreagegoal or the ciarity goal would be rhroushdetaile

LITERATURECITED Batiuk, R A., p Bergstrom,M. Kemp, E. Koch, L. Munay, J. c. stevensoD,R, Bartreson,v Cartcr,N. B. Rybicki, J. M. Landwehr, (".fr, C. Catiegos,f_. l. f.,f"yf.., D. wilcox, K. A. Moore, S. Aifstock and M. Teichberg.2000.Cheiapeake Bay iubmelged lquatic yegetation w'atel Quality 'tnd Hqbitat-Based Requirementsancr Restoraion Tatgits: ,l second rechnicar Slztiedrr. CBP/TRS 245100EpA 903_R_00_014.U. S. EpA Chlsapeate Bay program, Annapolis,Maryland.

Boynton,R. W, J. H. Garber,R. Summersand W. M, Kcmp. 199j. Inputs,transtbrmation$, l"j lTrllT.:l ^r]rrogcnan{t phosphorus in ChesapeakeO"y uiO triburaries. Estuari es | 8( | Bl:.285_3 | 4 _ ""r..t"a

ch.r p Lc|. ii . lcchnicai,tnd Modclinq Considcrationsfor Si.ttingthc Cap LoaclAllocattors and-carbon dioxide mass Cai, W. J., L. R. Pomeroy,M A. Momn andY Wang 1999'Oxygen in the southeastemU S' batancefor the estuadnc-intertidalmarsh complex of five rivers Limnologt and Oceanogtaphy 44(3):639-M9 ' Bay EutroPhication Cerco, C. F. and M. Noel. In preparation,2O03' The 2002 Chesapeake Center'Vicksburg' Model. EL-I3-XX. U.S. Army EngrneeringResearch and Development Mississippi. Yegetationmodel for Cerco, c, F. and K Moore' 2001. System-widesubmerged aquatic Chesap€akeBay. .6stuuies 24(4)'.522-534

cerco,c.F,'M'R.NoelandL'C'Linker'Inpress,2003'Managingforwaterclarityin ChesapeakeBay. Journal of Enironmenlal Engineering to the Chesapeuke ccrco, C. F., B, H. Johnsonand H V Wang 2002' TtibutaryReJinements D C' ERDC TR-02- BayModel. Final Report.U S. Army Corpi of Engineers,Washington' 4. 201 pp. managemcntstrategies Conley, D. J. 1999. Biogeochemicalnuhient cycles and nutricnt HyIrobiologiu 410 81-96 growth^studiesin a coastal D'Elia, C. F., J. G sandersand w R. Boynton 1986' Nutrient Journul of ptuin fly,oplankton growth in large'scale,continuou s cultnrcs'Canaditn Fisheries""t"ryiand Aquatic Science43397-406 Haasand S Maclntyre ln Fishcr,T. R., A. B. Gustafson,H. L. Bemdt' L Walstad,L W EstuLries' review,2003.The uppermixed layer of ChesapeakeBay, USA to assessP limi- Fisher,T. R. andA. B. Custafson.2001. Draft rcport on Bay-widebioassays of Natural Resources' tation and N distribution in spring.Report to Maryland Department Annapolis,Maryland- R L Wetzel'R Magnien' Fisher,T. R.,A.B. Gustafson,K. Selner,R. Lacouture,L W Haas' variationof resourcelimi' D. Everitt,i. Michaelsand R. Karrh. 1999'Spatial and temporal tation in ChesapeakeBay. Marine Bialogt 133:-76J-7'18' 'fhe phosphorusin ChesapeakeBay Fisher,T. R. and A. J- Butt 1994 role of nitrogenand Committee' Chesa- n ro*i . STAC Lit€ratureSynthesis. Scie[tific and TechnicalAdvisory peakaR€search Consortium Edge\xater' Maryland'

Fisher'T.R.E'R'Peele,J.W.Amm€manandL.wHardingJr.lgg2.Nutiientlimitationof phytoplanktonin ChesapeakeBay. Marine Ecologt ProgreruSeries 82:51-63- restore and protect Gallegos, C- L. 2001. Calculatiog optical water quality targets to p"ttiti"-"]ig-tlj di{Iuseatt€nuatton J-!tr"O aquaticvegetation: Ovcrcoming problems in coeffrcient for photosynthetically active radiation Estu'lries 24:381-39'7 Hagyand R' Bartleson Kemp,W.M.,S.B Bfandt,W. R Boynton,C J Madden'J Luo'J ChesapeakeBay ln: isgal's"*1ti" filtration, nutricnt inputs, and hypoxia in mcsohaline of Natural EcosystenMotJels oJ the Patwent ii'"' *iuo'y' Maryland Department Resources,Annapolis, Maryland. CBRM-CRF-94-2' Pp 51-72' SelnerandJ Kevin' Malone,T. C. D. J. Conley,T. R. Fisher,P- M Gilbert,L W- Harding'K ChesapeakeBay' Estusries 1996. Scalesof nutrient-limitedphytoplankton productivity in l9(28):371-385. of submersed Moore, K. A-, D. J. Wilcox and R. J. Orth 2000' Analysis of tlle abundance 23(1)ill5-12'7' aquaticvegetation communities in the ChesapeakeB^y' Estuaries

Settingthe |:ap LoadAilocations ch.lF)tcr iii - Tcr.hnic.:l;nd 1\lodclinqConsidefJtion5 for -ery

{

Neubaucr,S,, W. Millcr and L Anderson.2000. Carboncycling in a tidal freshwatermarsh ecosystem: a carbongas flux study.Marine Ecology progressSerres 199:13_30 Ncwell, R. I- 8., J. C. Comwell and M. S. Owens.2002. tnfluenccof simulatcdbivalve biode- position and microphytobenthos on sediment nitrogen dynamics: A laboratory study. Lim nolog/ .!n.l Oceanography 47(5): 1367_137 9. SecrctaryTayloe Murphy. 2003. "summary of DecisionsReganling Nutrient and scdiment New Submer8edAquatic Vegetation l:""Ojl":**, "id lSiaVyn"estoration Coals.,t April z), zuuJ memomndumto the principals, Staf Committeemembers and representattvesof the chesapeake Bay headwaterstates. virginia oIfice of thc covemoq Natural Resources Secretariate,Richmond, Virginia. STAC. 2003. Shoreline Erosionand ChesapeakeBay Watereuality: A ScientiticEvaluation ofPrediction Uncertainty,potential for Improuemeni,und ManagementImplications. Scien- tific and Tcchnical Advisory Committee, ChesapeakeReseal Consortrum.Edgewater, Maryland.

U S. EPA. 2003a. I nbient Water euality Criterialor DissolvedOxygen, /qter Clariry and C^llorcph):ll the Chesapeake : for Bay and lts Tidsl Tribut triei. epa SOf-n-Og_OOZ. ChesapeakeBay ProgramOffice, Annapolis,Maryland. US. EPA..?003b,Technical Support DocumentIor the ldentijication of Chevpeake Bay Usesand AttainqbilirJ,. ?esiSna.t:d EpA 903-R-03_004.Chesapeake Bay program Office, Annapolis,Maryland.

.h.rpt.r iii . T|chni.,tl.rnd i\,4odclinqCon!idefafions ior 5ett _.qlhc Lip l-oa{:iAilucations ,'r{

chapter lf SettingNutrient and SedimentAllocations

allocatingthe This chapterdescribes the specificprocesses involved in derivingand processeswere cap loads for nutrients and sediments.While many alternative is only the processultimately agreedto and followed.by the partners are "*pto..O,a.'."rit"i. Th! p.o""*.", for deriving sedimentand nutrientcap load allocations distinct and are describedseparately in this chapter' taken: To establishcap load allocationsfor nutrients,the following stepswere baywide . A basinwideloading cap was established'which requiredidentifying a the Bay' The load that would meet the dissolved oxygen criteria throughout Bayvide sectionsGeographic Location and Criterion Driving the Allocation ar.d Bay's tidal iop toarlin[ Optroasbelow, respectively,identifies the parts.of the allocation. waiersand the ciiteria thatwere most criticatto establishinga baywide Steering' ond p..r"n* the cap options that the ChesapeakeBay Water Quality CommitteeexPlored .Thebaywidenutrientcaptoadsweredistributedamongthebasinsandjuris- Basins rlictions. The section Distribuling Basinwitle Allocations lo Maior rules and altl Jurisdiclions below (page glfdescribes the principles' decision jurisdictions' processesused to distributethe cap loadingto the basinsand the . The initial processdid not result in sufficientnutrient reductionsto achieve baywidecap loads.As describedin the section?'he PSC Completesthe Allocalion Processbelow (page99), it was necessaryto haveinput from the Principals'Staff Committeeand headwaterstate representatives to completethe allocations' ensurethat . The dissolvedoxygen-based nutrient allocationswere examinedto Loatl tfr"y ."roluea ony ,imaining chlorophylln problerns'The brief sectionCap the A Lcqtionsro ichieve the Chloroihyll a Criteria below (page99) reviews resultsof this analYsis. To establishallocations for sedim€nts,the following stepswere taken: alloca- . SAV restorationgoals were set and usedto derive the sedimentcap load why the tions.The section,S'4 V Restor(]tiont]s the Goal bdlwt (page103) explains process' SAV restorationgoals were usedin the sedimentcap load allocation loads . Sedimentloadings were divided into two major sourcecategories; upland (page104) and ncar-shoreloads (page 105). 'lllocutions . Sedimentallocations were set. The section SAV-BqsedSediment process' below (page 106)tlescribes the scientificand policy basesfbr that

Llr.rt)tcr iv . 5i)ttingNtrtr ent 'lrld !L'dim{lntAllocallont The mathematicalmodels describedin ChapterII were usedto identify the sources of pollutantloadings and relate reductionsin thoseloading ,ou."", to ,tturn]n"nt of Bay waterquatity criteriaand 11"Sl,":l**" restorationo"f una".*"t.. tay grasses, n]l.",nese models provided a good L1^i,i]_J understandingof projecied water qualrtyellects trom pollutant sourcereductions, policy decisionswere necessaryto derivean equitabledistribution of the allocatedload. chapter III describesmany ofthe technicarissues that had to be resolvedbefore the allocationscould be derived. The technicalmethods and poliry JJsions that led to the nutrient cap load allocationsare discussedUeto*. g""au." th;se methodsand decisionsdiffered from those usedto developsediment alto"uiion., it pro""r.", fo. derivingeach are describedin separatesections. "

ESTABLISHINGNUTRIENT CAP LOAD ATLOCATIONS Threesteps were involved in settingand allocatingallowable caps on nutrientloads throughoutthe Chesapeake Bay watershedthat, i'ollectively,would restoreChesa- peakeBay and tidal tributarywater quality: l. The basinwidecaps on nitrogenand phosphorusloads necessary to attainthe Bay criteria for dissolved oxygenthrough all iiOd nuy nabitaiswere determined; 2. The loadingcaps were distributedamong the major tributarybasins by jurisdiction; and 3. Carewas taken to ensure thal the dissolvedoxygen-based nutnent cap load allocations would. also bring the Chesapeakefi"iy *a it. tidal hibutaries into attainmentwith the chlorophyll a criteria.

GEOGRAPHICLOCATION AND CRITERION DRIVINGTHE ALLOCATIONS Early in the processof developingnutrient allocations,there was a questtonas to was.ageographic location :-P19 th:." in the ChesapeakeBay fiUatwaters and a crrreflon(dtssotvcd oxygen or chlorophyll a) that would drive the nuhient cap load allocations.If such factors converged,then analysescould be ibcusedon that location and that criterion in derivingiutri"nt toiJuUocutio^.^O*o, if the cap load allocationseliminated "ap the water quality impairmentar that potnt, then they would likely eliminateall other impairmints ,.lur"d to nutrientsacriss a[ othertidal water naotrars.to explorethis issue, the modeledwater quality predictionswere reviewed (seeAppendix D lor modeled water quality resultsofvarious loaOingscenarios). The water quality resurtsfrom 'Tier 3 plus 20 percentnear-shore reductions, were usedin this.analysis because they consiitutedtire likeliest allocationscenario. The rolowtng oDservatronscan be made: . For dissolved oxygen, the migratory spawning and nursery and open-water criteriahave a high level of attainmeniund". observeaconOitions. . "ori"nt For dissolvedoxygen, significant nonattainmentis shownfor the pamunkeyaad Mattaponi rivers. This nonattainmentis observedunder all loadins scenarios ch;t prr.'r . iv 5"rl'']q\'tt..Cni .r^d S.rlirer,l 4 Or.i.Ons resultingin natural becauseit is due to naturalconditions (extensive tidal wetlands in establishing oxygenconsuming processes) antl for this reasonis not considered Document(U.s. the illocations foinutrients. chapter 5 of the TechnicalSupport EPA 2003b)addresses this issuein greaterdetail' criteria was highestin . For dissolvedoxygen, nonattainment of the water quality mainstem (segments ine Jeep-waterpo'.tions ot the middle ChesapeakeBay the deep-watercnterla CB3MIi, Cs4Mii and CB5MH) It should be noted that only apply in summer,from Junethrough September' .Forchlorophylla'theChesapeakeBayanditstidaltributariesachieveasetof local areas' numericaltaryet concentrations except for a limited setof were establishedto These obsewationssuggested that if the nutdent allocations porlions of segments achieve the dissolved oxygen criteria in the de€p-waier for dissolvedoxygen iSgttlH, CB4MH antl CB5MH, then all other impairments III for details)' ana ctrto.optrylta would most likely be corrected(see Chaptet

BAYWIDECAP LOADING OPTIONS oxygen,nonattainmentin Having establishedthe importanceof conecting dissolved CB5MH' it was consid- i;; de;p-waterportions of segmentsCB3MH, CB4MH and their water i. explorevarious baywide nutrient cap load optionsand "."Ji-p"n".,quality effects on thesesegments. control scenanos'or ChapterIII discussesthe developmentof variousmanagement The tier scenarioswere ,i"ra, ift* were usedfor deriving the cap load allocations' the Chesapeak€ basedon increasingpoint and ninpoint sourcecontrols throughout of eachofthese control eay *ut"r.n"A. ft J loadsdeliverei to tidal watersas a result This control scenarro ,"*urio, were then derived through the watershedmodel approachbecause: upprou"hwas consideredsuperior to a straightpercent reduction nonpoint technology . The tier scenariosprovrde a senseof the actualpoint and ncccssaryto achievcthe loadingsland attainabilityanalyses' . Costsfor tier scenarioscan be estimatedfor usein use

FiveOptions ExPlored on the tier approach'were Ultimately,five bay nutnentcap loadoptions, based largely responseto options,and tire model projectionsof th€,water quality "*pf,o.",t.'ift"." lV-t and IV-2 tftJ., ut" below andare furtherdescribed in tables "*pfoin"A per year' phosphorus load Option l: Nitrogen load capped at 160million pounds a model simula- ot tZ.t"*ittion poiias per yean This option wasactually bay dissolvedoxygen tion"opp",t that naa been run and ...uit",l in full attainmentof the cap loads under criteria.r Therefore it representedthe lowest end of basinwide was unknownat the time consideration.While this option resultedin attainment'it whetherhigher lording options would also result in attainment

degrceoJ nonattaitment dre to Gilllfiur", modclresults for optionI showeda small ouo,ity deep-channeldissolved oxvgen cntena ;;;";;;i"g; i;t ihe partners)in how the dccp-waterand woulLlbe aPPlicd.

.ihdptcr iv . !clti'rg i'lrrlri0ntand ScdirncntrilJocation! Option-2: Nitrogen load capped at ITS million pountls per year, phosphoras load capped at 12.6 mirlion pounds per yean This option, whicir consirJersall but the deep-waterportion of segment CB4MH, was developed acknowledging that attainmentofthe dissolvedoxygen criteria in deep-waterpo.tion of ,egrn"oici4tUtt is diflicult. While the total loading under this option i, not much different from Option 3 (5 million poundsnitrogen and 0.g miliion poundsphosphorus less), the critical difference is the geographicdistribution ofthe cap loadings.ihe cap loadsfor Option 3, comparedwith this Option, are higher for the northem tributaries(where additional reductionsimprove the Bay's water quality) with lower cap loads in the southem tributaries(where the impactof loadson Bay waterquality is much less). Option_3: Nitrogen load capped at ItI million pountls per year, phosphorus load cappedat 13,4million poundsper yean This oftion representedthe applicationof the Tier 3 level ofcontrols acrossall major tributarybasins. tt wasconsidered viable becauseit perceived was at the ttmeas an equitable(all basinsat Tier 3) and feasible allocationby the Water euality TechnicalWorkgroup and rhe Water euality Steering Committee. Option,4: Nitrogen load capped u lgg mittion pounds per year, phosphorus load cappedal I3,j million poundsper yean This opiion was createdas an alternativeto Oprion 3, after recognizing that Virginia's lowei westemshore tidal tributarybasins had a much lower effect on the dissolvedoxygen depletion in the middle mainstem chesapeakeBay potomac, than the eastemshore aad northem westernshore tidal tributary basins. The nutrient cap loads for the Rappahannock,york and James basinswere setto their existingtributary strategy leuels of nutnenrreductions. This option was established to determineif simirarwater quality rcsurtsto option 3 can be qained, despitethe higher loading,at a rower cost to ih" lo*". westernshore Vrginia tributaries. Option-S: Nitrogen load capped at I9g million pounds per year, phosphorus load capped u 15,7million poundsper yean Like Option +, Opiion 5 is pridominantly basedon Tier 3 levels.However, the three lower Virginia we;tem shorehibutary basins'caploads were increasedto year2000 progress'ievels. Again, this option was exploredbecause it was knom from previousBay water qualty model scenarios that thesethree tributary basinshad less impact on ttre water quility of the Chesa- peakeBay than the eastemshore and northem westemshore tributaries. Like Option 4, the partn€rs wanted to explore whether Option 5 would provide water quality results similar to Option 3, despitethe higher loading, at less cost for the lower westemshore Virginia tributaries Although the five options focusedon assessingthe effectsof nutrientreductions on the ChesapeakeBay and its tidat tributaries,it was necessaryfor th€m to be applicableto subsequentsediment allocationsas well. Therefore,each option includei a 20 percentreduction in near-shoresediment loads. The five optionswere intendedto tlerive a basinwideloading cap fbr nutrients.At the sametime, theseoptions not only consistedof different bisinwide cap loadings but.also._different geographical distributionsof thosenutrient cap loadingsto the major tributary basins.For distributingthe loadingto individual basins,however, a more deliberate approach was necessary.Discussed later in this chapter, tile approachwas basedon threeunderlying principles that sought to assurethat the allocationprocess was both equilableand feasible. cha p tcr - ' i.ll. 1..tlr"'.1' \.\t iv l,l ,,rU T(,nl \r tr.,t ,-rnr year) by the Tablelv-'t. Basinwidenitrogen cap load options(million pounds per developed b"il-- Water QualityTechnical Woikgroup, broken down by t"iotjlluh'y Option 5 Basin 1 Option 3 '15.9 (r3) 69.2 (T3.25) 82.6(r3 82.6(r3) 82,6 (T3 r3.2(T3) EastemShore-MD/DE l0,6 11.9(T3 l1.2(Tl) r3.2 (T3) 10.5(r3) WestemShore-MD 8.0 9.25 .2s) 10.5 r0.s r (T3 l. t (r3) Patuxent 2.s(r3.5) 2.8(T3 3. 17.9(r3) 37.9(T3) Potomac 30.5(T3 34.2(r3.25) 37.9 5.0(r3) 5.0(T3 5.0 s.0(r3 5.0(T3) (TS) 8.0(2000) 5.7 f . / 5.1 5.? 28.1(TS) 28.1 28.t 15.6(2000 1q (rs) 2.r (2000) EastemShore-VA 0.7 0.9(r3) r.e 188 tg8.t fdtal 160.4 r'14.8 t0.li 't3-Tier the Tier I and EJ scenarios; Keyr 3 scenarioloading; T3-25- loading onequarter of the way between loadingi 2000 2000 progress i-1S--toading t attway botweeniier 3 and E3 scitta.io.; ts-t.ibutary strategy sccnarioloading.

peryear) developed by TablelV-2. Basinwide phosphorus cap load options(million pounds basin' the WaterQuality Technical Workgroup, broken down by maiortributary Option 4 Basin I Option 2 2_83(T3) 2.83 Susquehanna 2.s4(T3.5) 2.69(T3.2s) 2.83 (r3) 1.29(T3) EastcmShore-MD/DE t.29 t.z t.29 r.29 ?s\ (r3) 0.?7(T3) Westem Shore--MD o.62 0.'7 o.1'7 0.77 o.24(',f 3) 0.24(T3) Patuxett 0.20 0.22 o.24 (T3) 3.r8(r3) Potomac 3.r8 (T,3 2.86 3.t8 3.r8 (T3) 0.66(T3) Rappahannock 0.66(T3 0.66 0.66 0.66 0.48(TS) 0.79(2000) York 0.48 0,48 0.54 (rs) 5.70(2000) James 3.'tI 3.',7| r.7l (TS) 0.22(2000) EastcmShore-VA 0_r0 (T3 0.09(rs) 0.l0 0.09 l2.7ri 12.6| | .r..!tt 13.25 I5.6lt theTier 3 andE3 scenariosl Kcy:T3 -:Iier3 sccnarioloading; T3.25 loading orc quart€rof theway bctween 2000-2000progress iil5-loading halfwaybetweeniier 3 andE3 sce-narios;Is-tributary strategyloading; scenarioloading-

cha!)l.r iv - SettingNjutflcnt ,rnd Sedinler.lt Allocations Factorsfor Selectingthe BasinwideNutrient Cap Loads tn selecting the most appropriatebasinwide cap loads from the hve optionsconsid_ eredabove, the Watereuality SteeringCommittee considered three factors: l. Basinwide natrient cap loads should protect the living resources in the Chesa_ peake Bay and itstidal tributaries,The purposeofthe allocationis to identirythe cap loads necessaryto achievewater quality standardsthat conformto the Chesa_ peake Bay criteriaand refinedtidal-water designated uses. This goal ofprotecting living resourcesby determiningthe nec€ssarycap loadsto do so is anlmportani conceptto kcep in mind during the state_specificdevelopment and adopiion of waterquality standards.

2. Easinwide nutrient cap loa.ls should be feasible to achieve. The Water euality Steering Committeeagreed that the Tier 3 loadinglevels were feasibleto achievl while achievingthe E3 loadingswere infeasible.ihe water quality model results suggested that loadssomewhere between the Tier 3 and E3 levelswere necessary to protect the living resourcesof the ChesapeakeBay. Obviously,the closerthe loading capscome to 83, the more concemexists as io their feasibility.As states work towardadopting waler quality standards,the issueof feasibility will likely be subjectedto further analysisand may becomean importantfactor requirin! fudher consideration. 3. Any nonattainment lessthan I percent is not consideredsignifican. It is impor_ tant to remember that the resultsreported here are model-simulatedresults and alreadyfactor in a definedlevel of allowablenonattainment. The Watereuality steering committee consideretlless than l percentnonattainment to be an artifact of the attainmentdetermination methodology and, therefore,insignificant. This lactor did not lavor one of the options. Raiher it was an lmporbnt screening device to identify significantnonattainment in the complexand voluminousset of modeling results reviewed throughout the cap load allocation decision makingprocess.

PredictedWater euality Responseto the FiveBasinwide Cap Load Options Apygndix D containsthe predictedwater quality responsefor the ChesapeakeBay and its tidal tributariesfor many loading scenarios,including eachof theseoptions (presented 'percent as nonattainment').Table IV-3 and figures IV_l througlr-lV-4, below,present the relevantinformation from Appendix D. i.gain, the nonattainment lor pamunkey dissolvedoxygen in the and thi Mattaponirivers is not included becauseit is due to naturalconditions (see Chapter II toi details.l. Table lV-3 providesan overviewofthe five optionsthat wereconsidered as possible baywidenutrient loading capsand a summaryofwater quality responsesto eachof the loadingcap options. As TableVI-3 indicates: ' The results of the various contror options confirm that the nutrent loads of the Rappahannock, York and Jamesbasins do not haveas significantan effecton the ch.rp-rt<-'riv . 5citingNutrlcnt anrl 5cdirrri:nt Allocalons Tabletv-3. Modeledwater qualityresponses to the five basinwidenutrient cap load options'l 4 Modeled Respons€s Option I Option 188 Nitrogen Loading t60 (million poundsper PhosphorusLoading millionpounds per year) Potomacand north, Eastem Ti€r 3.25

Rappahannock,York and Tributary Tributary JamesBasins Number of segmentswith >1% dissolvcdoxygen nonattainment (percenttim€ volume) '7 3.84 CB4MHdeeD-waternonattainment 3.9 6.0 .9 time volume) Area of Bay bottom with dissolved oxygenconcentrations

dissolvedoxygen conditions of the mainstemChesapeake Bay as the Potomacand Virginia EastemShore basins. Therefore, for all options but Option 3, the Potomac' westernshore ributaries north ofthe Potomacand EastemShore basins have higher levelsofnutrient load reductionsthan the Rappahannock,York atrdJames basins' . water quality improveswith eachincreasing level ofbaywide loading reduction. . The bay water quality is good for most metricsbelow underoptions I and 2 but declinesrapidly underoptions 3 through5. . Nonattainmentof water quality criteria in the middle central ChesapeakeBay (segmentCB4MH) doesincrease with increasedloading but not dramaticallyso' . The number of segmentsin nonattainmentis less under options I and 2 (one segmentimpaired) than under the otheroptions. However, note that only the deep- water portion of CB4MH is impairedunder Option l, while both the deep-water andthe deep-channelportion ofCB4MH is impairedunder Option 2 (althoughthe deep-channelimpairment is marginal)(Table IV-3).

FigureIV-l illustratesthe percentofthe ChesapeakeBay and its tidal tributariesin which the Bay bottom surfacearea is bclow I mgll dissolvedoxygen lor various loading scenarios,including the hve cap load allocationoptions' A low percentage ofbottom surfacearea with lessthan I mg/L dissolvedoxygen is a good indicatorof

ctr.t[)tor iv . ScttinqN]ritrent ,lrd S'lL.lim{rntAllocJtlons .i

o ;irv

I o oI aa '

I gE-- 3 t0 6

oo** r.' r t4r2 oprd.5 oorih. oprion3 opr6n 2 r$6/26.5) {2a6/l9.ll",ffi".l '2Btr9.o' p2trs.a) lrgs/1s.rl /tss/t33) fisrrs.4} {r/r12.61 Scanr.lo ( lkoganLoad/Phoaphoru. Load In m fionpound! pc. yaa.]

Figura lV-1,.Nitrogen phosphorur and loadversus percent ot the Baybottom sudacearea wrrn dtssorvedorygen concentrations less than 1 mq/1.

the extentto which the Bay may be habitablefor bottom sedimentdwelling worms and clams. Further,since phosphorus,and to some extent, nitrogen,are released from bottom sedimentspredominantly at dissolvedoxygen leve[ below I mglL, this analysisalso indicatesthe potentialfbr nutrient releasefrom theseserlimelnts. Figure IV- l showsthat: ' Loading reductionsrepresented by the observedthrough rier 2 scenariosachieve liltle reductionin_the percentage of the Bay bottomarea that has dissolved oxygen concentrations of less than I mgll,. However, reductionsbeyond the Tiei 2 scenariocause a dramaticreduction in the bottom area with dissolvedoxygen concentrationsof lessthan I mg/L. . Implementation ofoptions lor 2 achievedramatic improvernent in low dissolved oxygen concentrations along the Bay bottom in comparisonto Option 3. This improvementis due to the further nutrient reductionsrealized in ihe poto_"", northemwestem shoretidal tributariesand arongthe Eastemshore. These basrns are the ones that have the most impact on the dissolvedoxygen levels of the Chesapeake Bay.Dissolved oxygen concentrations of lessthan I mg/L arealmost elimirated with both options I and 2. Figure IV-2 identifies the model-simuratedvolume of the chesapeakeBay and its tidal tributaries, integratedover the lO_yearsimulation period, that do not ;fiain the

( hapter iv . 5cllingNrtfrcnt ,lnd Sr:diment AllocaLrons E9 E= EF E9 bE =6

.gb Ee ;8 !I c5 ;9 nro >! .og *E &6 3e og 10 E8 9< EE t: oplid 1 ob$d6d 2ooo n6r 1 Tlor2 Oodon5 option4 opliono oPion 2 (16{v12'8) ro"ne.o rra; i]l €61/is.o) (22ilts.l (1es/15.7)(1so/13 3) 081/134) {175/126) scene'lo (Nlttogoo Load/Pholphorur lnad in million pound! Per yeqr)

for FigurelV-2. Percent volume ot thechesapeake Bay and its tidal tributaries in nonattainment applicabledissolved oxygen criteria.

applicabledissolved oxygen criteria for numerousloading scenarios,including the hve cap load allocationoptions. This metric showsthe fractionofthe water column that providessuitable habitat for living resourceswith respectto dissolvedoxygen' Figure IV-2 showsthat: . Improvementsin watercolumn attainmentof the dissolvedoxygen criteria are not is dramatic until loading reductionsexceed Tier 2 levels While water quality improvingwith all loadingreductions, these necessary nutrient reductions are not enoughto bring many partsof the ChesapeakeBay and its tidal tributariesback into attarnment. . There is a dramatic improvementin attainmentthrough all five basinwidecap load allocationsstepwise tiom options5 through l. . while the improvementin attainrirentofoption I overoption 2looks significant' further review of the modeling resultsgives a betterperspective' Nonattainment just in the deep-channelportion ofsegmentCB4MH for Option 2 is 1'02 percent' barely over the estubli"h"d I percentthreshold lt is this deep-channelnonattainment that brings the total water column volume nonattainmentfor Option 2 to 7 percent.Without this deep-channelnonattainment, Option 2 would havethe same water column volume nonattainmentas Option 1 (4 percent)'

(:lr.rpL(-'riv - Setiilr,:JNutrlcnt ',lnC 5{lliil.nent Allocallors Figure IV-3 showsthe model-simulaled water surface area ofthe ChesapeakeBay and its tidal tributariesthat do not meet a s€t of targetchlorophyll a concentrationsin spnng.(Appendix C). Spring algae concentrationsand the timing of the spring algal bloomsare closelylinked to summerlow dissolvedoxygen levels. Figure lV_! showsthat: . There are dramatic improvementsin the water surfacearea of chlorophyll a achievement oftarget concentrationsthrough the entire rangeof load reductions, from 2000 progressthrough to Option I. . The dramaticimprovement in the water surfacearea of the ChesapeakeBay and its tidal tributariesin achievingthe targetchlorophyll a concentrationsbetween options2 and 3 requirescloser review. That is, underOption 3, the lower potomac estuarylevel ofnonattainmentis 1.53percent, while it is lessthan I percentunder Option 2. This small changein the level ofachievementof the targetconcentrations in the Potomac River accountsfor the difference in the baywide water surfacearea of nonattainmentbetween options 2 and 3. . The dramatic improvementbetween options I and 2 also needscloser review. That is, under Option 2, segmentCBTpH is 1.52 percent,while it is less than I percent underOption l. This small changein attainmentaccounts for the differ_ encein baywide nonattainmentbetween options I and 2.

80 E lr !€

i8e- aE FFE ; r-E s5i i $F iPE iE o= g< l0 o2

; ob!.ry.d 20@ Tb, r Opibds Opttona odton 3 Opabh2 OFion1 (336,23.5) (2391e1) (6tl1so) (1s&(15,/) (13€/13,3J (13r13'4) 1175/12.6)t160/12.31 Scanado (Nttmg5n Load/Phorpho.ua Load In ml lon pound! p6r yara)

Figure lV-3. Percentof water surfacearea of the ChesapeakeBay and its tidal tributaries achievingtarget chlorophyll a concentrationsin spring.

ch;rpr(_-riv - S0ttingNutIent.lnd Scdirrcnt Allocalion5 five cap load allocation The Water Quality Steering Committee debatedthese optionsat length and concludedthat: . options I anri2 providehigh protectionagainst low (< I mg/L) dissolvedoxygen from waters along the Bay bottom and provide significantly better protection theseeffects than options3 through5. to . Options I and 2 offer a similar level of water quality protectionwith respect 5' dissolvedoxygen criteria, superiorto that achievedunder options 3 through attainm€nt'and Although the fuater Quality Model did not simulatefull criteria the since the criteria and designateduse will be subjectto public review during states'water quality standardsadoption process' the marginallevel of nonattainment remainingwith theseoptions was consideredaccepbble' a- . As characterizedby the target concentrations,model-simulated chlorophyll 2 relatedwater quality effectswere largelyaddressed with the applicationofTier five ????loading reduciions.While the chlorophyll o improvementthrough the taken cap load all-ocationoptions is signihcantin Figure IV-2, cautionshould be not to overestimatethe actualimprovcment, given the localizednature of algal- relatedimpairments. 2' . Although the water quality responseof Option I is similar to that for Option Option 2 costsless and is more t'easible. Basedon this infomation,the water Quality SteeringCommittee recommended million basinwidecap loadingsof 175million poundsof nitrogenper year and l2'8 quality poundsofphosphoruJper year. These cap loads combined the bestBay water and.livingiesource protection and feasibility ofall the potentialoptions'

DISTRIBUTINGBASINWIDE ALLOCATIONSTO MAJOR BASINS ANDJURISDICTIONS to the Once thesebasinwide cap loadswere identified,they neededto be allocated stake- 20 major basins,by jurisdiction' in the watershed-To enablestates and local holdeis to develop tributary strategies,it was necessaryto divide the basinwide of the Bay nitrogenand phcsphorusloads into cap loadsfor eachof these20 areas stake- wateishedfor which tributary strategieswill be devetoped'States and local cap holderswill identify the actionsnecessary to achievethe nutdent and sediment load allocations. the Figure IV-4 delineateseach of the major basinsin the watershedand identihes the Sus- v#ous jurisdictions for each major basin. In some cases(for example' quehannaRiver Basinin Pennsylvania),states have chosen to further subdividetheir will be ailocatedcap load into smaller watershedsfor which tributary strategies developed.

CuidingPrinciples of AllocationDecisions cap The discussionsand analysesofoptions for equitableallocation ofthe basinwide loads loads were extensive.The policy decisionsfor allocating the basinwidecap is a were drivcn by an overall desirefor equity and achievabilityAchieving equity complexand somewhat subjective undertaking ln additionto equity,the Chesapeake

(-hapter iv - Scttinql'lutricnt and scdimentAllocdtlons Chesapoaks Bay Ba3lns LJ EASTEFNSHOBE MARYLAND/DELAWAFE EASTERNSHORE VIRGINIA ef, JAMESRIVER BASIN I PATUXENTNVER BASIN Iy I POTOMACFIVER EASIN MPPAHANNOCKRIVER BASIN rn SUSOUEHANNARIVER BASIN f WESTERNSHONE MAEYLAND I YORKBIVER BASIN

70 35 o 70 Mr|6

Figure IV-4-The ma.iortributary basins and jurisdictionsin the ChesapeakeBay watershed.

5!rlting lltrtri(:nt,r nd !cd rm{..lrt Alloc,l tro n! Bay Program partners factored in the feasibility of achieving reductionswhen distributingthe cap loadings'All the partnersagreed that the E3 scenariowas not feasible.Similarly, the partnersagreed that Tier 3 was feasible Hence,the Chesa- peakeBay Programpartners limited allocationsoptions to below E3' and The ChesapeakeBay Program partners succeededin framing an equitable process' feasibleapiroach by applying threeundertying principles to the allocation prln- The speciiicprocess that was usedto distributethe allocationbased upon these ciplesis providedlater in this chapter.The underlyingprinciples were: l. Basinslhqr contrlibutethe most to the problem must do the mosl lo resolvelhe prohlem. The ChesapeakeBay water quality model allowed-.thepartners to determinethe relative impact of each tributary basin on the dissolvedoxygen problemsexperienced in the middle mainstemBay and lower tidal PotomacRiver' iigure lV-5 showsthe relative influencefrom eachbasin Basinsthat have the griatest influenceon the Bay water quality will generallybe requiredto achieve the highestpercent reduction of nutrientloads-r do more' States 2. Stateslhat heneJit mostfrum the ChesapeakeBay recovery must that encompassiheChesapeake Bay and its tidal ributaries in its stateboundaries' realize e.g., Maryiand, Virginia, Delaware and the District of Columbia, will griut". t"nentt, sucihas tourism dollars,than others'This pnnciple was applied West 6y capplngthe reductionsfor nontidal states(New York, Pennsylvaniaand Vttginiu) ot a lower level than reductiontargets suggested through application of Principlel. 3. AII retluclions in nx rient loads are crediled kmanl achievingfnal ussigned loads.This principle was adoptedto avoid penalizingstates that have achieved significantnutrient reductions.It was applied by establishinga'baseline'load in uslng2010 land useand population,but no point or nonpointsource treatment plac; (2010anthropogenic ioad;. Sinceall reductionswere ftom this baseline'all pastand existingbest managementpractices and treatmentupgrades were credited towaRiihe neededreductiods. The aboveprinciples guided the Water Quality TechnicalWorkgroup in allocating the loadingsamong the major tributary basins,but a more detailedapproach was jurisdiction Aiter neededin-order to divide the load among the major basinsby prin- exploring alternativesto allocating the basinwidecap loads basedon these a more detailed tn" Watcr Quality Technical Workgroup recommended "ipt"s, Bay Program approachto the WaterQuality SteeringCommittee The Chesapeake p'annersagre"(l to the following decisionrules tbr dividing the cap load allocation: l. Basinswith the gresteslimprlct on the Buy mustcchieve the highestcontrols- Although ,"gtn"nt CB4MH was consideredthe critical areaof focus relativeto look dissolvid oxlgen in establishingthe basinwidenutrient cap loads,a broader at waterqualiiy effectsthan the original tbcuson CB4MH was preferredfor deter- To mining which tributarybasins has the greatestimpact on the Bay waterquality

nibo- 2Enrliermodeling sNdies indicated occan inputs were r!'sponsihlcfor 29 to l6 Pcrccntofthe total Bry (Thomannr;t rl g* i"".fi.g 1ap:proximotcly13l rnillion iotrnds 1er ycerl to rhc Chesapcakc (clative impact on ile+). fl"r" occan loadswetc a constaotfactor in thc modet-brsedanalysis of water illustratedin Figure IV-5.

(-lr,rpt.rr;v - ScllinqNuiricnt and !c'limcntAJlocation! avoid an overly narow assessment, basin impactson water quality conditionsin segments CB3MH, C84MH and C85MH we-reassessed. 'Relative impact,(i.e.,comparative water quality-Chapter impactofthe major basins)was usedto determinethe impac-ton the Bay (see .relative III lbr more details).To denve the impact'ofeach basinihe waterquality motietwas run with all basinsbut one (isolated) j;;;;g basin se_tat their (2000 progress).The isolatedbasin was setat the "*irring Tier 3 levelofcontroli. tie w"aterquatity model was run nine times,thereby ,isolating, eachof the nine major basins.In this way, the water quality improvementfrom 'Relative reductionsfrom eaci basin could be modeled. impact, was chosen_over.absolute impact, becausethe latrer, which measuresthe impactofthe total loadingand the hydrologicproximity ofthe basin with the depresseddissolved oxygenconcentrations in the mrddleBay, was deter_ mined to be arbitraryand unfair t the larger .relative basinsanJsubsequently dismissed. To calculate impact,, ,absolute ,normalized, iirpact, was by dividing it by the nitrogen and phosphorus loading flr each basin. Hence, the approach measuresthe impactfrom each basinfor iach unit ofnutrient loaddelivered to the Bay's tidal watersand approximates only the hydrologicproximity ofeach basin. Figure IV-5 showsthe relative ,normalized, influence,O"t.rrin"A ?orii u impact assessment,of each basin^on- 'Bay the dissolved oxygen concentrationsof segmentsCB3MH throughCB5MH. Using the ChesapeakeBay 'influence water quality model, basinswere grouped basedon their relative lper pounj nurient toadingj on the dissolved oxygen concentrationin the identified segmentsof the mainsiemChesapeake Bay. In this analysis,the chesapeake program Bay partnersdecided to assessthe combined nitro-genand phosphorusload impactson ttremiaate malnstemChesapeake Bay (CB3MH throughCB5MH). .no.rutir"A-,Uy Theseloads *"." orru*_g tnui iir poundsof nitrogenhad the impact of I poundofphosphorus. The potentialload impactsfrom both nitrogen 'algal and phosphorus*"r" ttu. into the term units' (seeChapter III for more rletails). "omuin"d . Finally, basinswere grouped basedon their influenceon improvlng the dissolved oxygenconcentrations in segments CB3MH throughCB5MH (Fie;re IV_6).The Virginia Eastem Shore, pi***- SusquehannaRiver, niu". and Maryland WestemShore were foundto havethe greut"stinflo"o"" on the dissolvedoxygen levelsofthe middle mainstem Chesapeakenay and, ttrerefore,grouped as basins having high impact on the Bay tidai wate, q,i"fi,v.'if," p"iomac River and the Maryland/DelawareEastem Shorebar;n. rv"." fo*aio t u* rnoo".ot" impact the middle on mainstemChesapeake Bay water quality. fn" nuppahannock,york and Jamesriver basinswere found to havea low i_p*t on the middle mainstem ChesapakeBay water quality. 'equal 2. An percentreduclion'ofrhe 20r0 'anthmpogenic u::"^,::: load.wourdbe usedas a e.g,lginqof basinsid.,t#J;;,;, lhe chesapeakeBay rrogram partners!'::yrh. agreed that load reductionswould be basedon an equalpercent reductionof anrhropogenicload for all basinswithin u ;;;; g.oup. Using2010 populationand land use.estimates and assumingno pornror nonpoint controls in place, watershed model runs ,n"." to calculatothe total loadingdelivered to Bay tidar "ondr"t"J wate6 from uurin. it" wltershed model "u"t was

.h.r pt{-r - iv SettingNutfjerrt.tfrd Scdiment Alioc.rtions concenlrarronconcentratlon FiourelV-5. Relative impact of majortributary basins on the.dissolved.orygen allocatinsthe basinwidenutrient ;;il;;"t^;;A;;.p.i"r," t"v ,rtli *"' ioniia"t"a when cao loads.

Allocdtrons chnplcr iv ' 5cttjrrgl'lutrienl Jnd 5fdiment I E o.g 6 08 B o.z F9 o.o = E n<

!1 6 U.+ YP ne > r! -.- o-0.2 E o.r :^ ov q P ..j<5a o q g o:d) "ssf E E Ex :>-tr + s Hep Ee= fiE g 6 # t Chesapeak6Bay Trlbutary Basln Figure lV-6.The major Chesapeake 8aytributary basins groupea u..oraffiT"i, ,"tati* influenceon dissorvedorygen concentrarionsin,"q,n"ndcsiMi, iiarvrH anocesMH.

also used to calculate ,forested' the loads. The differencebetween these loads becamethe anthropogenicload. That is:

Ana|.ropog€dc rord (2010)= Loadings withour controb (20I0) - Forest r-oad (2010) The Bay partnersagreed to equalpercent reduction of the anthropogenicload as rne bestexpression of equity. It is importantto reiteratethat the basrnshad been groupedas to their impact on the Bay water quality.Therefore, to implementthe first principle above, the basinswithin irouj *"." ."qui."o to achieveth€ "uch samepercent reduction of their anthropogenicload. After exploringoptions for dividing the reductionsamong the threebasin groups, Bay Programpanners agreedthat while the percentredJction oiioading within eachgroup was the same,there wourd n"""r.u.iry b" a sma[er fercent ,eduction required for basinsthat had less impact on Bay water quahty.tne issue then focusedon how much smaller a reduction U"t*""n g.oufa .o. upp.op.ru,".o differencein percentreduction betweengroups of 3 percentand 5 percentwas examined.For example, if the group of tributiry basinsthat affectedthe Bay the mostwas required to achievea 70 percentreduction in anthropogenicload, should the group of basinsthat had the next highestimpact be ,.qoirla ,o reducetheir anthropogelicload by 67 perc'ent or 65 percent,or someiher retluction?After exploring_theseand other options,the partnerssetectea a airrerenceof 3 percent betwcenthe basin_groups. This option kept reductionsfor an basinsw rin a more lhat is, th€_5 percent l:i.J"]., lTC option, which was considered,placed a nrgnerturden. necessitated high reductionsbordering on infeasible,for the most rmpactlngbasrns.

r:l-r.r[)t.'r . iv 5L,ttingNutficnt af(j SedimcntAllociltion,] ToachievethebaslnwldetargetloadoflT5millionpoundsofnitrogenandl2.8 to be translated million poundsof phosphorus,the 3-percentdifference. needed resultingpercent into actualpercent reduition for eachjurisdictional basin' T}r€ IV-6' retluctionsior nitrogenand phosphorusare shownin Figure the Bay needto Basedon applicationof the "basinswith the greatestimpact on decision rules achievethe iighest controls" and the "equal percent reduction" above,preliminary allocations were developedusing the equatlon: = tKl.ot ,."Ji1i'#1,:,',l lT[,"'T.;lilplJlfni ."au"toovro0l+Forest L'nd

TablelV-4 summarizesthe resultsof thisanalysis' ChesapeakeBay The abovedecision rules wete applicableto principles I and 3 The to betteraddress lro'gram partnersagreed that furt-herdecision rules were necessary the Bay partners friricipte't antl Principle2. Alier applyingthe abovedecision rules' agreedto the following additionaldecision rules' be setqt their 3. The Wryinia lributary basinsof the Yorkand Jamesrivers would River tributary current lrihutdry slrategt cap loads.The York River and James for nitrogen and strategiescalled for loading targetsthat were slightly higher. TableIV-4' Because slightly lower 1brphosphorus than the cap loadsproposed in partnersagreed the'tlifferencesare small and offset eachother, the Bay Progam phosphorusfor that the currenttributary strategycap load goalsfor nikogen and the proposedcap the York River and the JamesRiver basinswould be appliedin load allocations. greqterthan Tier 3 4. All nontidal snreswith nitogen or phosphorusrcductions from As further expres- decision rules I and 2 above would be adiustetl to a Tier 3 levels. that the states that sion of equity, the ChesapeakeBay Program partners agreed on a gr€aterburden beneliled most dlectly from the recovery ofthe Bay would take benefitmost ftom for the cleanup.Obvi;usly, thejudsdictionswith Bay tidal waters Hence' they nutrient reductions directed ioward Bay wa:aerquzlity restoration' York' Pennsyl- ogr""a to limit the loading reductionsoi the nontidal states-New vlnia and WestViryinia-to Tier 3 levels for nitrogen and phosphorus' of reductionsgreater 5. Forphosphorus, any ticlaliuristliction with an allacation rules I and 2 tho; ne; 3-4woultl be adiustedto a Tier 3 4 level' When decision to severalbasins- were appliedfor phosphorus,the resultantcap loadsallocated Rappahannock Eastern-Shore(VA), Susquehanna(MD), EasternShore (MD)-and that such (VA)--were o. b"yooi g3 levels. The partnersexpressed--concem "i for these high levelsof controlswere not achievable'Therefore' the allocations ba-sinswouldbesetataTiel3.4level,whichisaloadingequaltoTier3plus40 this way percent(0.4) of the differencebetween the Tier 3 andthe E3 loadings ln 'capped' (Tier than the tne tidai stateswere at a greaterloading reduction 3'4) those statesthat nontidal states(Tier 3), thus requiiing greaterreductions for benefitmore from the reductions.

ch;rpt.r iv ' Se'ttingNutfil'nt and Scdim{lntAlio(atLons 5.9 o

! t r{

a) [l:/:/:l:[l:l;Il;Ill;/:/:l;ff/:l:l;l;/i cE o:t gE l- ti o\ - |"t ll l,l l;l l/;/:/;/;/f od r: zl !q _v", l' = .,Y /;/;/;/:/;/;[/;/:/;l t!i; i.9 !*E - F L.,| E'l t obCc x9 II,l I1,l,l IIi./;/:FF/;/;F/:FF/:/:/r z t e.i : 'a nUa, ll q, FI z

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reflect deci- The preliminaryallocations presented in Table IV-4 were modihed to sionrules3through5.TablelV'5showstheallocationsthatthewatelQuality PrincipalsStaff iteering Committe-epresented to the ChesapeakeBay Program's cap loadsof Committeeahd headwater state representatives' Note that the basinwide phosphorusafter rules 187 million poundsfor nitrogenand l3'8 million poundsfor Committee's 3 through i were applied. Specifically'the Water Quality Steering and ono"ution, ]!ll *ttott of ttte agreed upon basinwide cap loads of 175 ofphos- "ulliuiii'.Srnlttion poundsby 12 million poundsof nitrogenand 1 million pounds 'orphaned phorus,respectively. These shortfalls were called loads"

THEPSC COMPLETES THE ALLOCATION PROCESS staterepre- In the springof2003, the Principals'StaffCommittee and the headwater million poundsper sentativespiomptly approvedthe basinwidecap loadingsof I75 the water yea. of niirogenuna ii.t -ittion poundspet year of phosphorus'which Table IV-5 shows' iluality Steeiing Committee had recommended'However, as reductions ,i"o--.nd",i j-urisdiction-basinallocations fell short of the nutrient poundsofphos- n""a.a. f*"tu".illion poundsofnitrogen reductionsand I million jurisdiction-basins'The o*, t",lu"tion* still needed to be assigned io the ft in i'ri*iputt' Staff Committee and headwater state representativessucceeded committedto the addressingthe'orphaned loads'by sharingthe burden The EPA Skies initiative, which is estimatedto bring fursuit oiaOoptlni the proposedClear to the Chesapeake uboo, un 8 miition pounAreduction of nihogen loads delivered In a genuine Aay an

CAPLOAD ALLOCATIONS TO ACHIEVE THECHLOROPHYLL A CRITERIA amount of As the previousdiscussion demonstrates, nutdents not only deptessthe growth' Therefore' dissolvedoxygen in the water but also promoteexcessive algae Bay' the EPA uiong *ittt nuteric criteria for dissolvedoxygen for the Chesapeake algal alsolecommendednanative chlorophyll a criteriato protectagainst excessive alloca- growth (U.S. EPA 2003a).Early in the processof developingthe cap load the dissolved iions, it appearedlikely that n;ftient controls designedto achieve There- o*yg"n would alsobe adequateto achievethc chlorophyll a criteria' "rit".iu to that of forel the analysisof nutrient allocationsfor chlorophyll a was secondary nutrientallocations for dissolvedoxygen. a After developing th€ nutrient cap load allocations, th€ resulting chlorophyll After concentrationswere assessed to delermineif furtherreductions were necessary' concentrations the cap load reviewing the model-simulaiedchlorophyll a -under cap load allocatioi scenario(see Appendix C), further adjustmentsto the nutrient allocationswere deemedunnecessary.

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.:f r;'lI)I{'r' - rv 5|ltrrrrJ l.,lLltticnf .trxl !,ldiiIL]t t Allo.r tto|! were drawn Targetconcentrations of chlorophyll a by seasonand satinity regime Guidance(U'S' froir the technicalinformation putli.h"d in the RegionalCriteria rl concentrations EPA 2003a)(see Appendix C). -omparing thesetarget chlorophyll 'confirmation' chlorophyll a with the cap loai allocations scenario simulated concentrationyielded the following findings: similar . Chlorophyll a levels relative to the target concentrationswere very 'confirmation' nutrient betweenthe scenarioand Option 1, indicatingadditional a concen- reductionsdown to the Option I levelwould not yield largechlorophyll scale' tration reductionsat the ChesapeakeBay Program-widesegment 4 concentrations . only in very localizedtidal habitatswere the targetchlolophyll not achievedunder the'confirmation' scenario

ADDITIONALALLOCATION CONSIDERATIONS nitrogenor Recognizingthat nutrient effectscould be lessenedeither by reducing pho.p'to*s] o, by other managementcontrols that would alleviate low dissolved Programpart- Lxygenconcentrations in the Bay's tidal waters,the ChesapeakeBay Murphy 2003). ,rers*agreedto keepthe nutrientallocations flexible (SecretaryTayloe tribulary basin Any jurisdietion can exchangeloading for a nutrientfrom one major effectiveness to anothdras long as the basinswere in the samegrouping of relative (seeFigure IV-6). phosphorusreduc- A jurisdiction may exchangeor credit nitrogen reductionsfor adverse'but tions. It is importantto notethat both nitrogenand phosphorus have an the nutrientallo- exchangeable,eiTcct on the waterquality ofthe ChesapeakeBay' so meansany cationscould be viewed as'nitrogen equivalents"Nitrogen equivalent' bay grass managementaction (e.g., phosphoruscontrol, oyster or underwater known quan- restoration.etc.) that has the similar water quality effect of reducinga 'tity of nitrogenloading.

ESTABLISHINGSEDIMENT CAP LOAD ALLOCATIONS SAVRESTORATION AS THEGOAL the The cap load allocationprocess for sedimentsoriginally focusedon achieving for focusing water clarity watcr quality criteria. However,good reasonsexisted load allocations -onug"*"n, plans and eventhe establishmentof the sedimentcap positiveshift on the-recovery of the underwaterbay grassor SAV beds'This was a in emphasis,fbr the following reasons: . It directly measuresthe healthofthe underwaterbay grassliving resource; .AnnualaerialsurveysenablethepartnerstotecordandmeaslfetheSAVbeds' whereas,sparse water clarity dataexists for Bay tidal- and shallow-waterhabitats; at presentreliably simulate . The ChesapeakeBay water quality model cannot . and shallow- reductionsin sedimentloads or water clarity responsesin Bay tidal- and waterhabitats at the desiredgeographic scale with sullcient accuracy; record . [t accommodatesthe transientnature of SAV growth' which the historical clearly documents,whereas water clarity criteria necessitatedrigid boundaries'

.:h.rplrr iv . Scllinll i\lutricntJnd ScdirncrrtAllocations While acres of SAV have become the dominant measureto tlirect management controlsofsediment within the tributarystrategies, water clarity still playsan impor_ tanl.role.The EpA haspublished water clarity criteria for the protectionofthe SAV in the Regional Criteria Guidance (U.S. EpA 2003a). In the Technica!Support Documentthe EPAalso identified SAV rcstorationgoals for the ChesapeakeBay^and its tidal tributaries (U,S. EpA 2003b).Curently, sledimentsare dischargedinto rhe Bay's tidal watersin quantitiesthat cause exceeiance of the watercraritv criteria and prevcntachievement of the SAV restorationgoals. In response,sediment cap load allocationshave beendeveloped along with thi SAV restorationgoals lbr eachtrib- utary basin. Sedimentloads that aflect water clarity and SAV growth in the Bay and its tidal tributariescome from two major areas: l. Land-basedloads originate from land erosion, are dischargedin runoff and includestream bank erosion;and 2' Near-shore erosion is attributableto tidal shorerineerosion and includesresus- pensionof sedimentmaterial from the shoreline. Model results have indicatedthat sedimentstend to aff€ct areasin the Chesapeake Bay and its tidal hibutariesclose to where they are introduced(see chapler it for rletails).For this reason,the Bay and its tidal tributarieswere dlvided into discrete secuonsrepresenting areasalIectcd by the l0cal sedimentloads that had little to no impact on other (see areas Figure III-20). Theseareas roughly correspondwith the nlne ma1ortributary basinsofthe Bay.

LAND-BASED(UPLAND) SEDIMENT ALLOCATION As the previous section points out, the Water euality Model is not capableof ptoviding a reliable understandingof the setiimentloads, effect on w6ter clarity. Therefore,it was necessaryto derive and agreeon reasonablesediment cap load allocations without a similar level of quantilativesupport liom the Water (juality Model as was usedin establishingthe nutrientcap loaj allocations. Since.no reliable modelingtool existed,neither water clarity criteria attainmentnor SAV-basedsediment cap load allocationscould be developed.Sediment cap load allocations,therefore, were basedon sedimentloads (reductions; that would likely r;sul1 from implementing the land-basedphosphorus controls necessary to achreve the dissolvedoxygen-based phosphorus cap loid allocations. It is well-known that for nonpointsources, most BMps thatreduce phosphorus do so by reducing the sedimentthat caries the phosphorusto the stream.Thus, phosphorus and sediment controls fbr nonpoint sourcesare closely relatcd. Frgure lV_7 illustrates the strong correlation betweenphosphorus and scdiment load reductions from BMPs. The methodology .phosphorus usedto determinethe equivalent,sediment loads was rclatively straightforward. Since increasingcontrol scenarioswere alreadydefined (e.9.,Tier I throughE3), the first stepinvolved identifying the ticr level represented hy the phosphorus cap roadallocations arready establishe-d to achievethe dissolved oxygenand chlorophytla criteria fbr eachmajor tributarybasin. lf the phosphorus cap kradallocation wasbetween two loadinglevels (i.e., two tiers),the exacttier was

'lr.t,. clr.r[]t(.r iv . "rrir Dt ,rrrl,, rrr. ,.- ,\ll.l,.r:.or {tsSediment -+ Phosphorus 23 22 21 20 19 18

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13€ 12c 11I

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3 2 1 o E3 2010No BMPS 2010Tier I 2OlOfl€l 2 2010Tierg 2010

and FigurelV-7. chesapeake Bay Watershed Model simulated relationship between 5€diment nonpointsource phosPhorus loads. interpolated.Once the tier for the phosphorusallocation was identified,the sediment cap load allocationwas determinedby calculatingthe correspondingsediment load tbr that tier. lt is important to recognizsthe tentativenature of theseallocations' which aredriven by the anticipatedsediment loads after the phosphoruscontrols are in place.The tributary teamswere, therefore,given latitude in identifying alternate land-basedserliment allocations if it could be shown to be more appropriatefor achievingthe SAV restorationgoals tbr that particulartributary basin' 'phosphorus After the equivalent'sediment loads were estabtished, these land-based (e-g.' sedimentcap load allocationswere moditied for severalmajor tfibutarybasins potomactidal-fiesh and susquehanna)because the chcsapeakeBay Watef Quality Motlel and existing data suggestedthc previouslydetermined land-based sediment allocationswere greaterthan necessaryto achievethe SAV restorationgoal tbr that particularmajor tributary basin.For thesebasins, the sedimentcap load allocations wererelaxed to levelsestimated to be appropriatetbr that basin"fable tV-8 provides thercsulting allocations.

ESTAELISHINGTHE NEAR.SHORE sEDIMENT ALLOCATION Due to an insutlicicnt technical understanrlingof near-shoresediment f'a!e and transport,no specilic rccommendationfbr near-shoresediment load reductionswas recommendedwhcn the lantl-basedsedimcnt cap load allocationswere established' Tributaryteams shoultl acquire local knowledgeofnear-shore erosion problem areas and makesoccific recommcndationson reductionsin thosesediment loadings'

1 l).rl)tcr iv . lctlinq i\,ulri(lntrln(l !;fdiircnt Aliocatlou5 5AV.BASEDSEDIMENT CAP LOAD ALLOCATIONS Scientific undersrandingof the quantitativerelationship between sediment reduc- hons and SAV recovery is less broad than the current understandingof the relationship betweennurrient loads and tlissolvedoxygen on Bay tidal wateis.Thus, the tributary teamsshould note the following when establishingiherrsediment/SAV relatedcomponents of the tributary strategies: l. The local SAV goal shoald semeas the primary goal in establishingsedimenl control measures by the tibutary teams.Attaining more SAV acreagels the most direct measure of the statusof this living resourceand can be measureddirectly. Therefore, ifall managementactions prescribed in the tributarysfategy aretaken, yet the SAV restorationgoal is not attained,further measures should be employed. Conversely, if the SAV restorationgoal is achieved,yet all sedimentreduction measureshave not beenimplemented, then further managementactions may not be necessary. ?. Based on a comprehensiveSAV recoveryplan by rhe tributary teams,revisions to.lhe upland se.liment cap load ullocations mty be recomminded to the prin- cipats' .upland, Stalf Committee, where appropriate. As noted, the allocations are tentative. That is, th€ sedimcntcap load allocationsrepresent the sedim€nt load likely to result from implementingthe phosphoruscap load allocationsthat have been principals' establishedby the StatTCommittee and headwaterstate partners. Obviously,these upland sediment loads have only a qualitativerelation_ ship to SAV recovery Thus,these uprand setriment alrocaiions shourd be usedas a basis for sedimentcontrols unlessthe tributary teams,based on the tributary strategydevelopment process,conclude that the recommendeduprand sedimeni controls are not appropriate_In such cases,the tributary team shall identi$/ the upland sediment cap load allocationsthat are appropriite and also identify the managementactions nec€ssary to achievethose allocations. 3 . The tribulary teamsshould explore a comprehensivesuite of manqgement rctions to achieve the local SAV restoration goat It is oppu."ni thut upland sediment conholsalone will be insu{ficient1o achieve the local sAV restorationgoals in some areas.The tributary teamsshould assess varied and innovativemethods to achieve SAV regrowth in suchareas. Methods could include,but not be limited to, stream- bankstabilization, SAV plantingand near_shore erosion control, where appropriate.

SUMMARY OF NUTRIENTAND SEDIMENT CAP LOAD ALTOCATIONS Throughextensive modelingand an intricateinterplay of technicaland policy decisions,the Chesapeake program Bay partnersagreed to load allocahonstbr nihogen, phosphorus and sedinent for eachof the 20 areasof the ChesapeakeAay waterslej delineatedby major jurisdiclion. basinand Thesenutrient and seirment cap loadallo- cationsare based on achievingthe ChesapeakeBay waterquality cnteria tbr dissolved oxygen,chlorophyll a and water clarity, and thi baywide and local SAV acreage restoriltrongoals. Tables IV-9 and lV-10 providea full tabulationof the nutrientand sediment cap loadallocations by major tributarybasin andjurisdiction, respectively.

i:hnF)l.cr - 'rcttrni.l rv l.Jrltrirn t,tIrd 5r:rJtrIcn L Ailoc,tlio|.j 'phosphorus TablelV-8. Land-based equivalent'sediment cap load allocationby majortributary basin, by iurisdiction.

Land-Based Sediment Allocation Basir Jurisdictiotr (Million tons p€r year)* SUSQUEHANNA PA 0.793 NY 0.131 MD 0.037 lhsin-fotal 0.962 EASTERNSHORE - MD MD 0_ll6 DE 0.o42 PA 0.004 0.001 llusin't'otal 0.163 WESTERNSHORE MD 0.100 PA 0,001 llasin fotdl 0.100 PATUXENT MD 0.095 llasin Iolai 0.095 POTOMAC 0.6t7 MD 0.364 0.311 PA 0.197 DC 0.006 llasin lbtrt l ..194 RAPPAHANNOCK 0,288 l]rsin lbtal 0.t88 YORK 0.103 llilsin lbtiri 0,l0l JAMES 0.925 0.010 llu.'inTbtal 0.9.15 EASTERNSHORE'VA 0.008 lhsin li)tal 0.00lJ sulf f()IAL +.r5 t],.\stNWlDll l o'l:\ l. t.r5 *The tributarytcams will asscssthese upland sedimentallocations and, ifnecessary,rcvise thcm rs part ofa comprchcnsivestratcgy of m;ndgementaciions necessary to achievcthe local SAV rcstoratrontoals.

ch,rpL.rr iv . !icitif(Ji\utrrL'rrt.rnd 5rrr.lirncnt Allocations Tablelv-g. ChesapeakeBay watershednitrogen, phosphorus and sedimentcap loadallocations by majortributary basin.

Nitrogen Phosphorus UplandSedimert Cap Load Allocation Cap Load Allocrtlon Cap Load Allocation Easin/Jurlsdiction (million pounds/year) (milllon pounds/year) (million tons/year) SUSQUEHANNA I,A 67,58 1.90 NY o.793 12.58 0.59 0.l3l MD 0_83 0.03 5 t lS(){.ll.ilIA 0,037 NNA Iirtll r0 9,) l.i2 0.962 EASTERN SHORE - MD MD 10.89 0.81 0,116 DE 2.88 0.30 PA o.o42 o.27 0.03 0.004 0,06 0.0t l'11\S{ LltN , 0,001 SII(}l{ll V t) l'r)rll 14.r0 L l4 r).163 WESTERNSTIORE MD | |.2'l 0.84 PA 0.t00 0,02 0.00 0.001 WllslllltN SllOitli Iorrl IL29 0 8,1 0.1()0 PATUXENT MD 2.46 o.2l 0.095 I)AItixIN'l li)rdl 2.46 0ll r).{)r5 POTOMAC t2.84 t.40 MD 0.6t7 ll.8l 1.04 0.364 wv 4.'tI 0.36 PA 0.31I 4.O2 0.33 o.197 DC 2,40 0.34 i)()l'OMA('lirrdl 0.006 .r5.7li .l."18 L.1()4 RAPPAHANNOCK 5.24 o.62 0.288 l{/\I'l'AIL'\NN(J(K {)rir t I 5.14 (J.6) (].t81l YORK 5.70 0.48 Y()l{K'lirtrLi 0.103 5.7r) {r{3 i).l0l JAMES 26.40 3.41 o.925 0.03 0.0| L\),1irSIinal 0.010 ::6..1.J .t..t2 ()9J5 CASTERNSHORE - VA l.l6 0.08 l:.,\SllrltN SllOltl.l- 0.008 \,,\ ti)rll r rb 0.08 {).001.1 SUBTOTAL 183 12.8 4.t5 CLEAR SKIESREDUCTION -8 rt,\5t\\v )rqt ()f.\r, t75 |.]i ,t l5

( l).rpLL'r iv - !,ril n(Jj\itrtril)rrt Jl](J !{til'|lrt.nt Allot,rlir.:ns allocationsby Table lV-10. ChesapeakeBay watershed nitrogen,phosphorus and sedimentcap load iurisdiction.

Nitrogen Phosphorus Uplartd Sediment Cap Load Allocation Cap LoNdAllocatioE Cap Load Allocation (mitlion tons/year) Jurisdiction/Basin (million pounds/year) (million pounds/Year)

PENNSYLVANIA o.793 Susquchanna 67.58 1.90 0.197 Potomac 4.02 0.33 0.001 WestemShorc 0.02 0.00 - 0.03 0.004 EastemShorc MD o.z7 ().995 I'A lbtrl 71.90 2.16

MARYLAND 0.83 0.03 0.037 Susquchanna 0.095 Patuxcnt 2.46 0.21 0.364 Potomac Il.8t L04 Shore I t.2'7 0.84 0.100 Westem 0.1l6 Shore- MD 10.89 0.81 Eastem 0.1t2 !1D l-otrL i 7.25 ).92

VIRGINIA 0.617 Potomac t2.84 1.40 5.24 o.62 0.288 Rappahannock 0.t03 York 5.70 0.48 26.40 3.41 0.925 Jamcs 0.001 EastemShorc - MD 0.06 0.01 0.008 EasternShore - VA l.16 0.08 I.9,11 VA lotal 51.10 6.0o

DTSTRICTOF COLUMBIA 2.40 0.34 0.006 Potomac ().I 0.006 I)C lbtal 2..10 +

NEWYORK 0.131 Susquehanna 12.58 0_59 0.llI NY Li)tal 12.58 0.59

DELAWARE o.042 EastcmShore - MD 2.88 0.30 0.042 I)ll'I'otll Lx8 0..10

VIRGINIA WRST 0.31I Potomac 4.',lI 0.36 0.03 0.0r 0.010 James 0.1.1() WV fotal ,1.i5 0 -i7 4.15 SUBTOTAL 183 t2,a CLEAR SKIES REDUCTION -8 .r.r5 |J,\SIIWU)ll I ()l:\ l. 175 t 2.ll

( hiptcr iv - ScttingNutrr(,'nt rnd !(ldimentAllocdtlors Nutrient and sedimentcap load allocationswere establishedbasetl on the EpAs recentlypublished RegionalCriteria Guidance(tJ.S- EpA 2003a),which is specific to the Chesapeake Bay. Therefore,the stateswill be modifying therr water qualrty standards basedupon the publishetiBay criteria as we as thJ refined tidal-water designated.uses. If the finat adoptedsta; waterquality standardsdo not rely on the criteria and designateduses employed to establishthese cap load allocations,then the allocationswill needto be amendedaccordingly. It will be dillcult to achievethese cap loadallocations. States will developtributary stmtegiesfor eachofthe 20 areasby April 30, 2004.Some states may choosefurther to subdivid€ their tributariesinto smallerwatershed for the deveropmentoftributary strategi!'s.These tributarystralegies will identify speciticactions needed to achieve thecap load nutrient and sediment cap load allocations.

LITERATURECITED secretary'laytoeMurphy, 2003. "summary of DccisionsRegarding Nutrient and setlimcnt Load Allocations and New SubmergcdAquatic Vegctatio"n1Sa:Vj Resto.ationCouts.,, April 25, 2003, principals' memorandumto the Staf iommittee ,"rni"r, _o representa- trves of th€ Chcsapcake Bay headwaterstates. Virginia Officc of the Covcmor, Natural RcsourcesSccretariate, Richmond, Viryinia. U.S. Environmentalprotection Agency,2 OO3a.Ambie,tt Wster eualiry CriteriaJor Dissolved Cltrity und Chlorophyll .n(t.tl ?:!,gi,I,^W!,il aJbr the Chesapeakeioy oia t,, Trihuraries. tPA 903-R-03-002. program ChesapeakeBay Otlice, Annapolis:Ma;iand. U.S. Ervironmcntal protection Agency. 2003b.Technicot Support Document l.lentiJica_ tion ol Chesapedke Jbr Bay Deiignated UseEand Atainqbility.6pa SOf.n-O:_00+.Chesapeake Bay ProgramOffice, Annapolis,Maryland.

( fr.rl)ltr . iv l;rtttnq NItlcIll artrll;r,rlirIr}rt Ailoc,tltons appenLlixA SummarYof Decisions RegardingNutrient and SedimentLoad Allicationl and New SubmergedAquatic Vegetation(SAV) Restoration Goals Memorandumfrom W. TayloeMurphy, Jr', Chain ChesapeakeBay Program Principals'Staff Committee' to the Principals'Staff CommitteeMembers and Representativesof ChesapeakeBay "Headwater"States

N''!v !AV R''toritinrl Coa s .rppc-ndix A . Llrt(l5rorl'l lir,'r.;.r<11n9 \lr.r".l(lrri ii Scllirn(lntloJ(1 Alkr':'rllorts ln'l COMMONWEALTHof VIRGINIA Affrcc of tlv Guenwr W, Tade Muqfir, ,r. P.O. Ed 1{75 (80rl?86$a.t S.s..-r of Nj[J t rtd Rld|[md, VlrgtDh S2fS BE(60{,5?l{t 3 TTI(t(8Olt?E ?t6t

To: PrincipalStaff Committec Mernbers and Representativcs of Chesapeate Bay "Headwatcl'States

W.Tayloe Murphy, Jr., Chair Spf ChesapeakeBay Programprincipals' Staff Cotunittco

I)ate: April28.2003

For thepast twenty years, thc ChesapeakeBay partrershave been committed to achicvingand maintaining water quality conditions ncceesary to supporrriving resourtes tkoughoutlheChesapeake.Bay ecosystem, In thepast month" Chesapeake Aa:y frograrn partncn(Marylaod, Virginig pormsylvanigtho Dishict of Columbia.theEnvi-n-ult"t PmrectionAgency and rhe chesapeale Bay commission)havc expanded our effortsby workingwith theheadwate( stlt.' of D€laware,west viiginia andNew york to adopi newcup load allocations for nitsogcn,phosphorus and s€diment.

Usingthc beetscientific information availablg Bay pmgrampain€rs haveagr:eed to allocationsthat are intended to m€€tth€ nceds of tirc plantsand animals that iall the chesapeakehomc. Theallocations will sepo asa basisfor cachstate's tributary strategiesthat, when completed by April 20o1,will dcscribelocal imprementationactions necessaryto meetthe Chesapeakt2000 nuhicnt and s€diment loading goals by 2010.

This memorandumsummarizes the important, comprehensive agrcements made by Bay waterehedparlncrs rvith rcgardto capload allocations for nitogin, phosphorusand sediments,as well asnew bayrr.ide and local SAV reslorationgoale.

Nut er AUoclllont

Excessivenutrier s in thc chesapaa&cBay andits tidal tributoicspromote undesirable algalgrowth, and thcreby, prohibit light from reachingunderwater'b"y grasses (submergedaquatic vegetation or sAV) anddepress the dissorved oxygin leveleofthe deepowaters ofthe Bay.

Jp[)cllr-lrx /\ . I)C(i.,()]tsllc(j.rrrj,ng Nltr'rcnt yr _;j,liJrt{_,ntL.J,td ,/\ loc.ttiois Jtr(l NeW SAV ljcsloriltion CO,lls with the concwrenceof As a result,Bay watersh€dsiates a$d lhe Distist of Colunbia"- wat€rsat I 75 Ei;; ;;; tJ armualnitrogm loadsdelivercd to the Bay's tidal ""p pounds' It i8 estimatedthat rii[L"-p"*at ani umuat pnof,horus loadsat 12'8million of-nitog€n pollution by t l0 theseallocations wiil rcquirea r;;tio4 ftom 2o0()lwels, armually' million poun& ondphosphorue pollution by 5'3 million pounds Model partnersagreetl upon these load reductionsbasod upon Bay Water Quality The oxygcn' Tlre oroiectiourof attai'rue"t of p-p":;;;a;-q-rty At*in f"t dissolvcd 'model atro:(lc projectstlrese load reductionswill elimiretc the p€rsistentsutml€f, aro O. aeopbottom waten ofthe Bay' Furthermore'these reductions a) throughout projectea"o"Ati'"oJioto etirninatee*""."ive conditions(measured as chlorophyll "[a" the Bay andits tidal tributaries' load^fornitrogen and phosphorus Thejurisdictions ageed -basinto distributethe baryide cry 2)' distributionof bv niaiorrriUutary (Tablel) andjurisdiction(Table .This principles: J.oo-ti.it i,v roitoad rductions was basedon tkee basic quality would havethe l. Tributarybesins with the highestimpast on Bay water hi ghestreduotions of nutrients.

2'Stateswithouttidalwaters_Pennsylvania'NewYorkandwestVirginia- not henefit as would be providedsome re[ef mm principle 1 sinc6they do directly ftom improv; watet qualityin tho Bsy and its tidel tributaries' achiweinentofthe 3. Previousnutrient r€ducliots woukl bo croditedtowards capload allocations.

basedupon their The nine major tributarybasins were separatedinto thrce categories wasassigncd the same ;;;;ffi;q,talityin rheBav. eacntasin within a category impaclon tidal water DerceltrEduction ofanuuopogeJc load' 'Basmswith the highe$ of anthropogenicload' fi;1il ;;6Jiii; high"stpucentage raduction Pennsylvaniaand West After applyingthe abovecaloulations anrt Princrplc 2'New York' a_Ilocationsfor allocations*o" ,"t iJnutricnt toadtwets. Additionally, virginia Eibutary Vork andJames River "t-.fief basins were set at previously.established vi"fini"'s on mainstemBay o-oii.nt .op ro.a W"tt tili" t""io ttti nri"i*al imoact ""tn qourityis predominantlylocal' water"oJ,",gvquality conditi.*' *d th#;;;;" oo-tii"r *"te of 12 million pounds Theserules resulted in shortfallsto the baywidecap load allocation gpe to pursuethe Clear oi og* *a 1 million poundsof phosphorus' "omtitted tidal wat€rsby I "lt initiative whi"U i, erti*"tJ iJ .J.i." tt nirog* load to Bay Skies " for the million poundspcr ycar. nay ntaterstredstat€s agrecd to tak! respomibility of phosphorus'The r"tJttiig I tifri"t po-a, of oftog* arrdI n{lion.lounds ft"O il tablcs I and2 rcflcct thcscagrcomdrts' ""ol""t,ip "ttiatious

Nlcw5.'v llcstoraLion{ioals .rppr:r.rrlix ,A . iJcc.l!;of\1{t:qardinrl [lL]iricn'r & 5r:cllnrcntl-cacl Allocatlons.,lnd The.allocations for nitrogenand phosphonrs w."c adoptedwith thc conceptof ,,nitrogur equivalents"and a commit[€ot to explorehow actionsb€yond faditional b€st managcrnentpractices might help meetBay restorationgoars. A nir,ogencquivalent is an actionthat resultsin tho samcwatcr quality benefitas removing niuog€,n. Tirc chesapeakeBay Pmgremwilr evaruatehow to accountfor tidal waterquatity benefits liom,continuedand cxpandcd living resoucercstontiorl suctrr" oystc"s*i menhaden, to ofrsetthe reductionsofwatershed based nutrient andsediment loads, scasonal fluctuotionsfor biologicalnutricnt removerinpremcntetior! nutrient reduction benefiis from shorclineerosion reductionr, implementation ofenhanccd nutsient rernoval at large wasl'waterh'atnent plantr, ard Eadeoffgbetween nitrogen and phosphorus will alsobe evaluated.

BaywldeSAV RestorutlonGosl

To-set_new SAV restoraliongoals, scientists ard rcsourcemanagcrs hom stateand feag{ aqggr,eeaq{ to uscdata fiom the singlcbest year of obscrvedSAV growth to eshmateth€ historicallongierm bay grasscoverage in CicsapeakeBay. Datatere auial phorographsraken bctwccn i938 and2d00. From 3-4 yearsin tho 99!1t{-1964 _nom l93E period,and more than20 yearsofdata since 197E,new baywid; SAV restorationgoal acreagewas deteunincd by totatingthe singlc'bestpar acrcagefrom eachChesapeale Bay Programsegment.

Thc staleshave adopted I E5,000acres as the new baywidcSAV restoretiongoal to be - achievedby 20I 0 consist€ntwith thc gotrsof chesapearcz?000. The achievcmentof the beywidegoal, aswell rc thc locnl hibrrterybesin and scgmeot specific rwtoration goalssummarized in Table3, will bo basodon thc singletcst ycar S.nV acreagcwithin the.mostrerent threc-yearrecord ofsurvey rcsults. Tiis new acreagegoal hasbeen addedto tho r€centlycdoptod ehotogy to accelorctothe plotectionand restoration ofsAV in the ChesapcakeBay; ard Marylandand Virginia havi agecd to developan rmplementataonplan for this stratcgyby April 2004.

SedlmentAllocalons

Scdimeirtssuspendod in tho watercolumn reduco thc anount of light availabreto support healthyurd extensivesAV communities.with regardto the sediient alloc"tions, tiri primary !qF5."ry.:! Sat a rc_ason.forreducing sediment loads ro th€ Bay is to provide su[able habitatfor restoringsAV. Thejurisdictionsalso agrecd that nutsiontloact reductionsare critical for SAV restontionas wcll as improvingoxygcn lwcls. As a result.thc stat$ linked thc cstablishmenLof sodimartcap load-allocationsto the proposed wato cluity criteria andto the now SAV restorationgoalc.

unlike nutricnis- whcreloads from virtually alt partsof the Bay watcrshedaffect Bay mainstemwater quality - impactsfrom sedim€nt8ar€ prcdominantly s€en at the local level. For this reason,local SAV acreagcgoals have been establish€d s€diment allocationsarc targetedtowards achieving ihose restoration goalc. ",ld

ttl)p(lrl(-lrxn ' uccsio{15llcq,lrllln(l []utri{rJrl&5r:drrrtr:rf lo,rrl Ailo{,rtior).;.rnd Ncui 5AV R(.5toralron (rc,rl5 sourcesand their Thc partnersrecognize that the ourrentunderstaading of sediment g"i We haveooly a basicunde'rstanding of land- l.oi"i* tn" i8 not ]tet somplete' etosionud ;#il;;;" iil i-ita iio i*"1 *'r"o"vt tttugh stearnbak limited"" knowtiee o"artuo'" u"auTlg! B"v-d ii;rrl;;;; resusporunoq'T]::ry it" tia"l .i"t ait*tly tbroughshorclinc "tootcrorion or ohallowwat€r land'basedecdiment cap Coruequentlv,sediment alloiationg arc cunently focused-on z')' loadsby majortributary basil (Tablc I ) a.odjurisdictron ( I aDle sourcosof land-basedbest managcment practices which rEduce,noryoint Most thejurisdictions agreed to land- ilffi.;;ll ilJ"";t"dil;i;"ff' Thaefore' baseds€dimontallocauonsuatr€Pres€ntthesedimentloadinSlikelylor€suIffom phosphoruscap load #pr"-*"iti." tt^"dcnt actiinstequir"d to achievethe allocations. allocationfor each sedimentallocation wa8 set equal to thc tier level for phosphorus Thc 'phosphorus land-basedsediment j".t.dfi;;i;. Th;is r"r"n"d-to ; th" equivalent' 'phosphorus rErluctionswer€ foufld to reduction. Ifthe tq"it"f""iitia-Uased sediirent goals'thor tholand-based L" ."." O* ."..io*i to oni""o tft" looalSAV acrcagc the SAV goal' Theridal sedirncntallocations werc rais€d to that necessaryo achiJve two €xanrplawhere this ;;i"td;*;Flats andtialal ftesh Potomac-River are their tibutsry sFategies' rn.Jifr.a ipp.*f, wasapplied. lf, in thedwelopment .of needrEvisions' the il"t"w a#-" theild-bas€d sedimentallocations "".,c1,,

Supportb StalQTtibuaary StrG//"glzE strategiesby The oartnerslrave agced to completotheir nunientand s€dimcntrcductiotr of tributarvstategics' the chcsapeake Bav #i;,i*" ffi ;if,;,h; ;;;;i"ptcnt quality watetshed officewilt provroe an ifff oiioG"d -"tvt"t' water and Progam to thotibutary sEatcgy moiehg, cost-effectlivenessand economic assessment supporl tearnsthrough the states.

Go'lls & 5edirn(]nilo.rd Allo(airons rrril N':rySlV ll'l5tordtLon .][)t){]rr(l ix /\ . DLt{.5i()|rs litrlarrlinq NUtr]ctrt Thejurisdictions agreedthat it iscritical to wcrk togetherto assurethe contsolactions aggregateof recommendedwithin rf,e nutlcnr _i-rJ_J.t urcg", yield reductionsand the theload Bayand tidal tribut".y *uio q*iity-i.ii*r._"ru a"ri."A. Reevaluotion of the Allocaltons

cap.toadailocations adopred by jurisdictions screnir$sI:llflllTd.redirnent the arerh€ best estimatesof whatwill bc ncededro aftai; waterquarity tidal w-aterdeeignrted Foposed crireriaand usegdcscribod i" guia"r,"u p,r'bliJ;Jiy ina. years'Maryland O"u, ,t e nexr two virginia' Derawarcand th" Dirr.i;ie;#bi-a wil prornulgate waterquality standsrds new bas€don the guiaancepubtishod$iP;. Alrhoughthc pubric processfor adoptingwater quality srairdard, willpro$de ";"";;;;'rh;statcr, srale,spro"e., opponuniriesfor corrsideringand acquinng iew ""ch Ievel. informatronat thc rocal Statesmay choose lo exotor" n,,i,u", ori.ruo'a*i-ninl, suchas rhe " pro"."s, economicimpacr oiwater quallrysaandards and specitrc "aoption boundaries. designateduse

while the .'ocatio* adoDtedat this time wit providcthc basisfor tributary thescallocations $bategies, may needto bc.adjusteOto rcitect finJ .tuti*"t", quufity Furthennore,planned standards. Bav modclrifinrrn*tr - aite"t"o t i**lsfimating water quarity benefir from filter feedingresourcec (e.g., oysters understanding ard menftadcn)and bcft€r therour""r--d irr-riaii"*a:*ii'inlri* o* unaerstanding thc relationsiripbetwe€n "fr."c of nuticnt andsediment reduction, unO-i"l.g roor,,'e respons€s in the.Bay.For thesc reoaons,thc statesagced to a reevaluationofthesc allocations laterthan 2007_ no

As parhcrs, thejurisdictioru committedto corrcctingthe nutriant andscdiment related i" thc Bay and ry-bt"r: its tidat tributariessufficienil' ," ..r* O.," from the rmperrcdwstora undsr list of tho ClsanWatcr Act. Althougi tho-stJcsagrcod to do thcir umost.toremove thclay fron the dcml list of imfaired watersby 2010,they r.cognizcthat it w l be difficurt ro mq proiged w;ter quariiy stanoarosin aI partsof keyreason for rtris Omcutty is thiionJeiurient practrcg:T-l"yiy,h.", arc lT....A reduction installed.il mav be yeareor evendecades before thc Bay reductiom.The jurisdictiors bcnefitsfrom these i""ia,g r,*" p-g."rJiipii"" Iri'o*",i""ing by20t0 suchthat when fully implementcd attpan" of rf,i Say*J.*iJ,"O delisting. ," U*omeeligible for

my appreciationro ail thcparrrcrs in thiscliort for their wort*:-"11T!: andcommitnent " tPress hard to rcstorationof thcChesapeake Bay. We havc agreed lo nutfienl andsediment reductions whichwilr rcsurtin ptoro*Jimpiluoi*r" in o" *rter quality, habitatand living resourcerofrhe Bav

.t!)l).rr1(lrx/\ - l)Ltr-isiOn5llr,(JaJ(lItq lj|rln.r.tt& icriir]trtntLO.jd ,^lloi,ttl(j.ts ,l d N.tu,/!AV RCStOfdtiOn(rOals by TableA-1. Chesapeake Bay watershed nitrogen, ohosohorusand sedimentcap loadallocations majorbasin.

Nitrogen Phosphorus Upland Sediment Cap Load Allocation Cap Load Allocation Cap Load Allocation (million tonvyear) Basi Jurisdiction (million pounds/y€ar) (million poundvyear)

SUSQUEHANNA 0.793 PA 67.58 L90 0,l3l NY 12.58 0.59 MD 0.83 0.03 0.037 0.962 SLS(ll j EllnNN.,\'foral s0.99 2.52 EASTERN SHORE . MD MD 10.89 0,81 0.116 0.042 DE 2.88 0.30 0.004 PA 0.2'7 0.03 0.06 0.01 0.001 0.163 ll,\STI-.RNSI{ORti ' UD lotal t4.It) l.l4 WESTERN SHORE 0.100 MD n.27 0,84 PA 0.02 0.00 0.001 -lbtal 0.100 rVIISfE{iN SllOltL l i.:9 0.84 PATUXENT 0.095 MD 2.46 o.2l 0.095 Pr{flJXlrN'I'fotal 2.46 it.2 t POTOMAC t2.84 t.40 0.617 MD I t.8t t.04 $.364 4.'7| 0.36 0.3tI PA 4.O2 0.33 0.t9'7 DC 2.40 0.34 0.006 L494 l,()'loi\t.,\| loiirl -r5.trj l.4ll RAPPAHANNOCK 5.24 0.62 0.288 0.28! )tAl)t'AftANNo( K f otrL 5.24 0.62 YORK 5.70 0.48 0.103 0.l0J YOIIK fotrl 5.70 0.l it .,AMES 26.40 3.41 0.925 0.03 0.01 0.010 r,,\\.]ilslirill 3.,12 0.9i5 EASTERNSIIORE . VA 0.08 0.008 | .16 (Jt)tt Ir.r\SI l:R N SIIO lt li - V,\'li'txl L l(r 0.t)lJ 0. 4.15 SUR'[O'TAL 183 CLEAR SKIES REDUCTION ,{ tl,\st\wt lrE l'() l.\t, lt5 r:! i5

N|w \AV lic';tcralionc(),11s ,r1rJrr.,rr,.lixA . 1_jLjci!rorsftrq,rf{l rl l\l,tlfi{]lt& !r-\li|rrc t Lo,ltlAllo.iliion! and Bavwatershed nitrosen' phosphorusand sediment ,tir?li,l,3;ln-'"teake cap loadallocations bv

Nitrogen Phosphorus Upland Sedlmeot Cap Lord Allocation Cap l-oad Allocaalon Cap Load Allocation Jurirdictlon/Besin (millior pounds/ye8r) (milllon pounds/year) (million torVyear) PENNSYLVANTA Susquchanna 67.58 L90 Potomac o.793 4.02 0.33 W€stemShore o.t97 0.02 0.00 0.001 Eistem Sho.c - MD 0.27 PA li)1al 0.03 0.004 71.9(l 2.26 0.995 MARYLAND Susquehanna 0.83 0.03 Patuxent 0_037 2.46 0.21 Potomac 0.095 l l.8l 1.04 WcstemShore 0.364 | 1.27 0.84 EastcmShore - MD 0.t00 10.89 0.81 0.1l6 ,Vtl) liltll \7.2.5 2.9) 0.i 1?. VIRGINIA Potomac t2.84 1.40 Rappahannock 0.6t'l 5.24 0.62 0.288 York 5,70 Jamcs 0.48 0.103 26.40 l.4t tJ.925 EastcmShore - MIJ 0.06 0.01 0,001 EasternShore - VA Ll6 VA lirtal 0.08 0.008 5I.10 6.00 r94l DTSTRICTOF COLUMBIA Potomac 2.40 o.34 IXI l'Lrlll 0.006 1.10 r).l,l (,.00{t NEWYORK Susquchanna 12.58 NY.l(nll 0.59 0.t3l I 2..5s 0.59 0.ril DELAWARE EastemShore - MD 2.88 0.30 l)11irr1ll 0.042 I Erl () ](l 0.(.),12 WEST VIRGINIA Potomac Jamcs 0,36 0_311 0.03 0.01 0.010 ulV li)tirL t.l5 o.l7 0.-r 20 SUBTOTAL 183 I2.E 4.15 CLEAR SKIES REDUCTION B,\SlNlV )E',t()r,\1, r75 l z.lt J.I5

'rpt)crr(Jlx ' /\ l)tci'liQnsR|lllrdinq Nrltrr.nt & sr:rlimc'nt lo,rdAllcc.ttrolrs.rnd Ncw SAVR(l5toration G'.rls fable A-3. ChesapeakeBay submerged aquatic (sAV) restoration goal acreageby ChesapeakeBay Program (CBP)segment based on the singlebest year of recordfrom 1930to present Acres CB ITF

EastemLower ChesapeakeBay CB?!H-1 Mouth ofthc ChesapeakcBaY CB8PH I BushRivcr BsHoH t58 CUNOH 1)\L Middle River MIDOH Back River BACOH PATMH

SouthRivcr SOUMH RhodeRiver RHDMH West River WSTMH 214 Upper PatuxentRiver PAXTF 0 Middle PatuxentRiver PAXOH Lower PatuxontRiver PAXMH 1,325 UpperPgqqqa$lg POTTF 4,368 -783 PiscatawayCreek PISTF MattawomanCreck MATT! 2'16 Middle PotomacRiver POTOH 3.721 Lower PotomacRivcr POTMH Upper RappahannockRiver RPPTF 29 Iv'tid,tt"Rappohannock Riv". RPpOH - -9 iower RappahannockRivcr RPPMH 5'199 CorrotomanRiver CRRMH 516 PiankatankRivcr PIAMH Upper MartaponiRiver MPNTF 7l MPNOH

cohlinue.l

ilndNcw 5AV RestorntionLOJls .rpp{--n.lixA . Di:ci:ionsRcgarclinq Nrrtricnt & ScdimcntLoad A iocatiorls Iable A-3. ChesapeakeBay submerged aquatic (SAV) restoration goal acreage (hesapeake program by Bay (Cai) segmentbased on ihe singte best year of record from 1930 to present.(cont ).

JMSTF River APPTF 319 Middle JamesRiver JMSOH 7 iny Rivcr CHKOI,I 348 Lower JamesRiver JMSMH 5ll Mouth ofthe JamcsRiver JMSPH 604 WcstemBranch tslizabcth Rivcr WBEMH Southem[tnnch ElizabcthRivcr SBEMH EastemBranch Elizabeth River EBEMH

[-ynnhavenRiver LYNPH NortheastRiver NORTF C&D Canal C&DOH llohemia Rivcr BOltoH

ChesterRiver

Lower ChcsterRiver CHSMH 724 Ea.stem EASMH 108 Rivcr CHOTF u Middle River cl{oot{ Lower River CIIOMH2 1.499 Mouthof the River CHOMHI l-ittls ChoptankRiver LCTIMH Rivcr IINGMH FSI}MH 193 Ijppcr NanticokeRivcr NANTF 0 MiddlcNanticokc River NANOH 3 Lower NanticokeRivcr NANMH WicomicoRiver WICMH ManokinRiver MANMH Big AnnemessexRiver BICMI{ PocomokeRiver POCTF Middle PocomokeRivcr POCOti Lowcr PocomokcRiver POCMH '[lrngicr Sound TANMH lirtitl ;trrcs ,:::::::s":il:::T,",:-s^v D,ud(u@n or r.oromacrAv r€,storarionrestoration soars.bljlisdicrionssoah by julsdicrions nrerre drso,dran. Fndinspenrling connrmadonconfirmar ofsprjt betrccn Miryhnd. VirBinia|lnd tie ,/,ru,LrDrstrlctot o, \I otImhiaorumora .rtuDsirrong Jj unsdunsdrcrrondl iclion"f fi"".s.tjnc8. n,,.Du. tor" ongoing rclincm€nt,some numb€rs in ihis labl€ difIer fiom.rh-€Aprit.25, 2001, versioninctuded rndrnii pr€violls.r.wi^,,e m^,r-r -"*- _ , , in AppendixA nodel csrimatesprcscnred in tablcs|It_l rn,t lll_4.

'rl)r).rr{lix 'A ' Dcii!iollil1{l(l'lr(Jrn(l lJlitr llnt & 5.r1lr.}tntlo,r(l Alloc,rliorrs an{l N rr.v,", s^v RcstorationLo.ll! Iable A-4. ChesapeakeBay submerged aquatic vegetation (SAV)restoration goal acreageby major basin by iurisdiction'

SAV Restoration Gosl (Acres) SUSQUEIIANNA 12,856 EASTERN SHORE_ MD WESTERNSHORE MD PATUXENT POTOMAC' MD 12,'74'l 6,320 DC 384

r.483 EASTERN SHORE VA 3l,215

rBreakdownofPolomac SAV restorttion goalsbviurisdictions arc d'aft p€nding along confirmationofsplit betwcenMaryland, Virginia and the District ofColumbis uthlc Lliffer iurisrlicrionalhnc;. Due to ong,ringrefincmcnt. somE numbcrs in this irom lhc ADr'l )5. 2001,rcrsion irulude,l in Appendi,(A anrt nre\ious moLlel cslimarcsDres€ntcd in tcbleslu-l rod lll_4.

,lnd i'ltlv -qlwR{l!toration c'l'lls ,r1.>Jrr:rrrlixn . l)||., (jnslieq.rr(liIrt NutIcnt li lcLlnlcnt L-oildAllocatiors .rppendi* B ChesapeakeBay Living Resource-Based RefinedDesignated Uses and Water Quality Criteriafor DissolvedOxygen, Water Clarityand Chlorophyfi5

To betterretlect the desired and attainableChesapeake Bay waier quallty conditions calfed for in the Chesapeake 2000agreement, Ci,"rup.ut" B;ti;og-_ watershed partnersdctermined that the underlying tidal_wateriesignated usesneeded to be refined. The-ChesapeakeBay watershed panners,thus, ;;;J fivereJined suh_ ca'egoriesof 'he currentbroad aquaticrife designateduses contained in the existing statewater quality standards of the four jurisdictions borderingdirecfly on Chesa- peakeBay and its tidal tributaries. Four of_the refined designated uses were derived largely to addressseasonally distinct habitatsand living r€sourcecommunities witti *i,lely varying dissolved oxygcn requirements: . Migratory fish spawningand nursery: . Open-waterfish and shelltish; . Deep-waterseasonal fish and shellfish;and . Deep-channelscasonal refuge.

The tifth rcfined tlesignatetluse, the shallow_waterbay grassdesignated use, is a seasonaloverlay on that part of the year_round Sp*_*ui", u.r" .hich bordersthe land along the tidat portionsofthe Chesapeakee"y ii, iJirr"r*". ""J TableB-l generaldescriptions .provides of the five designatedrnes and the aquatic communrtiesthcy were establishcd to protectl, whili table B-Z providesthe proposeddesignated uses for each('hesapeake program Bay segment.See the ?Lc*_ n.ical. Sup po r t Do<: u me n t r tdenr ifi Jb cur i i n,,1 Ct * p i' r y i)" r igno, r o*t Atta.inebility(U.S, EpA 2003b) " "u7r" "a, ", for more detailedexplonution oiit" five refined designateduses.

lNote that lor breviiy,thcse rctincd dcsiunateduses may be rgfencd nursery, to' as migratory spawningand shallow-watcr,opcn.water, dcS_wate. nnOa"io-"f,onr"i-

.tf)l)(.rr(llx ll . livtnrl Rcs'urrr: B.t:c..Rciirtr.. l)r::irlnlLcrlLJi!15 dn{t \,V.tl{treuilltty (_'tcria tidal-waterdesignated uses' TableB-L Generaldescriptions of the five proposedchesapeake Bay

protectmi$atory finfish Migratory Fish Spawning and Nursery DesignatedUse:. Aims,to a*1! ttterat" *inter/spriig spawning n*t"y seasonin tidalfr"eshl-"]"i:::tJ;Y]::"", "ita many Bay tidal rivers and habitats.This habitat zone is pnmaili iound in the upper reachesof speciesincluding creeks and the upper mainstem ChesapeakeBay and will benefit several striped bass,perch, shad, herring and sturgeon' bay grassesand the Shallow-W|ter Bay Grass DesignatedUse: Designedto protectunderwater provided by grass beds' many fish and crab speciesthat depend on the shaiow-water habitat waterquality in the Open-Water Fish and Shellflsh DesignatedUse: Designedto protect the mainstem Chesapeake surfacewater habitats within tidat creeis' rivers, embaymentsand including striped Bay year-round.Thls use alms to protectdiverse popuiations of sportfish' silversides'as well as the bass.bluefish, mackerel and seatrJut,bair nsn suih as menhadenand listed shortnosesturgeon' to protectliving resources Deep-WaterS€asonal Fish and Shelllish DesignatedUse: Aims betweenthe well-mixed inhatiting the deepertransitional water columnLd bottomhabitats This use protects many surfaceliaters an

Source:U.S. EPA 2003b.

for deriving The frve tidal-water designateduses, in htm' provided the context quality criteria fbr the dissolved oxygcn, water clarity and chlorophyll rl water protecteach ofthe Ch"rup"ot" nu'Vand its tidal tri6utariesThese criteria' derivedto arrayof biolog- five reined designateduses, were based on effectsdata from a wide thousandsof aquatic i.ui to capture the range of sensitivity of the "orlrrnunitli estuarinehabitats See splies infraUitingthe ihesapeakeBay and tidal tributary Oxygen' WaterClarity and Chloro' ,imbient Wurerfuolity Crit"ito 7or Dissolved hs Tittal Tribut.dri:: more detailed pliyll u f* thi che'sapeuke Bov an't ^for '"*pi-",i"" (U'S 2003a) As of the ChesapeakeBay water quality criteria EPA criteria have been orcsentedin Table B-3, the ChesapeakeBay dissolvedoxygen presentsthe water claritv [;il;J;t of ,h" l,u" designateduses Table B-4 "J chlorophyll a criieria appticaUleto the shallow-waterdcsignrted use' The nanalive tributaries' is *hi.t is recommendedfor all ChesapeakeBay and tidal "rit",io,Dresented in TableB-5

and Watcr LrLtera ,r1'l1;<:rrrlixll - Livin(lii{l50uf.:c fJ'l'il(i llrrlirrcd llctirlndtrd lJrl: Qualrly TableB-2. Recommendedtidal-water designated uses by ChesapeakeBay program segment.

Migr.tory Sp.n[ing Ctelrpe.k€Bry Progrrn(CBP) cBf endNunery Open-Wrlar De€p-Weter DeeFchrnnel Sb.llow-Wrtcr SggnantNeme Segn.nt (2/l-5/ll) (Yerr.Rornd) (6/l-9/30) (6/t-9l30) (1n-10/t0)

Northem CBITF X x I ,U CB2OH I Uopcr Central C83MH x x x x Middle Central CB4MH x x l Lower Central C85MH x I WestemLower CB6PH x I EastemLowor CBTPH x 1 Moulh of the CBSPH I Bush River BSHOH x x River GUNOH Middle River MIDOH Back River BACOH River PATMH X x River MAGMH X X x SevemRiver SEVMH x SouthRiver SOUMH RhodeRiver RHDMH WestRiver WSTMH Patuxent River PAXTF x X WestemBranch WBRTF x Middle PatuxentRiver PAXOH x Lowcr PafuxentRiver PAXMH X' PotomacRiver AnacostiaRiver ANATF

Middle PotomacRivcr POTOH Lower PolomacRiver POTMH RPPTF x x Middle RPPOH Lower RPPMH

CorrotomanRivcr CRRMH x x X PiankatankRiver PIAMH U Rivcr MPNTF Lower i River MPNOH x River PMKTF x x x Lower PamunkeyRiver PMKOH x x Middle York River YRKMH X x Lower York River YRKPH

continued

.1frpcn.lix - F Living Rceoufcc,Ba5cdRr,:finccl Dcsign,ricd Usc5 rnd \ lattf eL.t,rlttyCfltori;l Tables-2. Recommendedtidal-water designated uses by ChesapeakeBay Program segment (conf')'

Migrrtory Sp.rtridg ch.r.pe.keB.y Progrrm (CBP) CBP .rd Nurg€r] Op.n-Wtte! DeeFwrter De.FchamelShallow-Wrter SrgmentNBne Segment (2n-5/ll) (Yerr-Rot|Id) (6i1-9/30) (6/l-0/30) (4il 10/10)

Jamesfuver

Middle JamesRiver JMSOH ChickahominyRiver CHKOH x x x Lower JamesRiver JMSMH x x r( Mouth of the JamesRiver JMSPH WestemBranch Elizabeth River WBEMH SouthemBranch Elizabeth River SBEMH EastemBranch Elizabeth River EBEMH

Mouth to mid-ElizabethRiver ELIPH

NortheastRiver NORTF C&D Canal C&DOH Bohemia River BOHOH Elk River ELKOH SassafrasRiYer SASOH Uooer ChesterRiver CHSTF Middle ChesterRiver CHSOH Lower ChesierRiver CHSMH Eastem EASMH Upper ChoptankRiver CHOTF x x Middle ChoptankRiver CHOOH x x x Lower Choptank Rivdr CHOMH2 x x x Mouth of the River CHOMHI

NanticokeRiver NANOH Lower Nanticoke River NANMH Wicomico River WICMH Manokin River MANMH Bis AnnemessexRiver BIGMH Upper PocomokeRiver POCTF Middls PocomokeRiver POCOH Lower PocomokeRiver POCMH TangierSound TANMH

SourcerU.S. EPA 2003b.

(-f .,rpr)en(1ix B - L vin.l ilc:ource Bast:dReflred Lielignated Uses .lfid \l/aief QLialiiy tcrra t6 l9

a I x _ ,l .t 6 I € F a

, ! g g ;$ en t ta F !IL bt .9 ,z .84 € ET 49 9 9 Eg Eit a a a9 ? s t>, 9 _.ci R €B .:t d6 s c lo.a 38 !9 :t E.g .E .sl $ t SE te .E o6 5 *t s -aA a ' :- El $l lf $l s6 f;9 ii E + t.i : €o' g ;E IE '.4 b€ -d it I g & o -6 .E s ls .!t il I6 c6 € !K s!l 3 ,t ,; .t iii FE] tt a5 E F t9 d b.l I al : F F g d '- E i 3 .E E (J E .; + ' € ra t{ o I T U c 4.. o o ctl E!1 g ,rl ,9 bo aoC =-i uX c z s .: .5 a (l, e2 ;,: ;t ., ' tE ,:9^, Al I q 9: 2E 9i I s a e 95 @ 6 9.! s 6 T o r:g 6,9 ro (u g G Efr OJ .9o h? E$ ix s5 sE,qa s ;< ..i 1a }E *='E €; q aEEf 'g .co Df 2 9bo AA F' u ? &E rf;E o* 33

.:r;rpcrirJix {l - LivrogRc5ource-B,lscd Rcfinr:d Dr:s!lnatcrl Us,:5.rn{l Watcr (lualltyCritcria TableB-4- Summary of chesapeakeBay water claritycriteria for applicationto shallow-waterbay grassdesignated use habitats.

Wrt i Cl.rtty Wrarr Cl|rtty Crlt.rt. .r Sccchl D.Fhr S.Intty Crltarla aa T.fipord W.t r Ctrrtty CrtLdr Apdkttur n RGEIn. P.rc.!l Ligll- f|l. Appllcrtlon througl-Wrt r 0.25 0.5 0.75 l-0 r.25 t.5 t-15 2.O (PLW) S.ehl D.D.r (Er.rt) 6r abov. Cdr.tt AIPbdo. Itqrl

Ti&l ftEsh L3OA 0.2 o.4 0.7 0-9 t.2 1.4 Ardl 1-OcrobcrSl

Olitobslic tt% 0.4 0.5 o.7 0.9 t.l 1.4 April I -Octobqll

Mcrohdinc 2 0.2 0.5 o.7 1.0 l.z 1.4 1.9 April l - eobc.3l Polyhalirr 22% 0.5 0.7 t-0 1.2 1.4 t.9 Much I - May 31, Seot lnbcr I - NoYEmber30

rBasealon apptication ol th€ equarion, PLw - I o0exp(-tqa, the appropriate PLW criierion value aDd the seL€ctedapplication deptb are insened andihe equation is solved for Kr. Tlre generated K.1value is then cowerted to Secchi depth (in meters) using the conv€rsion factor lQ: L45/Secchidepth. Source:U.S. EPA 2003fl.

TableB-5. Recommended Chesapeake Bay chlorophyll a narrativecriteria'

Concentrationsof chlotophyll a in free-floatingmicroscopic aquatic plants (algae) shall not exceedlevels that result in ecologicallyundesirable consequences suchas reducedwater clarity, low dissolvedoxygen, food supply imbalances,proliferation of speciesdeemed potentially harmful to aquaticlife or humansor aesthetically objectionableconditions-or otherwiserender tidal watersunsuitable for designateduses' Source:U.S. EPA 2003b,

LITERATURECITED

U.S. EnvironmentalProtection Agency. 20O3a. Ambiefi rfqter Q nlity Citetiafol Dissolved Oxygen, Watel Cldriry, and Chlontphyll afor ChesapeakeBay and iB ndsl Ttibutaries' EPA 903-R-03-002.Chesapeake Bay Progam Omce, Annapolis,Maryland.

U.S. EPA. 20O3b.Technical Suppott Documentft ldentirtcation of ChesapeakeBay Desig- nated (Jses dnd Attainabili\i. EPA 903-R-03-004. Chesapeak€Bay Program O{fice, Annapolis,Maryland.

.rpp,:nc1ix B . li,iing ResouT{cB.rs.ld Reiined Desiqn:tcd Uscs and Watef QudlityCrile na appendixC Summaryof WatershedModel Results for All LoadingScenarios

This appendixdescribes general assumptions and methodologiesapplied for several model scenarioused in the cap load allocation processincluding the 2010 Tiers, 2010 "Everything,Everywhere, by Everyone"(E3), 2010 No-BMps and All-Forest scenanos.

LEVEL-OF.EFFORTAND E3 SCENARIOS As describedin Chapter4, the Tier and E3 scenarioswere developedby the Chesa- peake Bay Program Nutrient Subcommittee,sWorkgroups to provide reference points of increasingload reductionsof nutrientsand sedimentthat could be associated with increasinglevels of BMp implementationfor both point and non-point sourcesin lhe ChesapeakeBay watershed.

The seriesof rangingscenarios were simulatedby the ChesapeakeBay program's Phase4.3 WatershedModel andthe resultantloads for nitrogenjphosphorusand sediment wereused as inputsto the ChesapeakeBay EstuaryModel- Evaluationof water clarity,dissolved oxygen and chlorophylla concentrationsfrom the EstuaryModel, in turn,provided a senseofthe responseofkey waterquality parameters to the various loading levels. For the Tier and E3 scenarios,best managementpractices (BMp) implementationlevels, the resultantmodeled loads and the measuiedresponses in tidal wat€r quality are informational.They are not intendedto prescribecontrol measuresto meet Chesapeake2000 nutient and sediment loading caps. Implementationlevels in all ofthe Tiers and E3 scenariosare not cost effective-The most cost effectivecombinations of BMps will be evaluatetlby iurisdictionsand their tributaryor watersh€dteams as their tributarysftategies are de-veloped.In addi_ tion, and as noted in Chapter4, E3 levels of BMp implementationare theoretical sincethe scenario,generally, did not accountfor physicallimitations or participation levelsin its desien.

.rpp(-ndix Ct - 5umnr.rryof W.ltcr5hcdMcdcl Re,sultsfor All Lo.rdinqScenario! oi

The Tier and E3 BMP implementationlevels were mostly deliberatedand setby the "source" workgroupsof the ChesapeakeBay Program'sNutrient Subcommittee Theseworkgroups are made up ofrepresentativesof ChesapeakeBay watershedjuris- dictionsand Chesapeake Bay ProgramOffice personnel. The specificworkgroups that decidedBMP implementationlevels included the Agricultural Nutrient Reduction Workgroup, the Forestry Workgroup, the Point Source Workgroup and the Urban Stormwater Workgroup. The Tributary Strategy Workgroup and Nutrient Subcom- mittee finalized the E3 scenariodefinitions aller review and further deliberation. To conform to Chesapeake2000 goals,all ofthe Tier and E3 scenarioswere rooted in 2010 projectionsof landuses,animals, point sourceflows and septicsystems as well as 2007/2010or 2020 air emissioncontrols. Landuses and anirnalpopulations in the ChesapeakeBay ProgramWatershed Model are developedfrom an array of national,regional and statedatabases as describedin ChesapeakeBay Watershed MoclelLsnd use and Model Linkagesto theAirshed and EstuarineModels (CBPO, 2000).The modeledlanduses include the following categories: . Forest . Conventional-Tilled(High-Till) . Conservation-Tilled{Low-Till) . Hay . Pasture . ManureAcres (model accountingof runoff from animal feedingoperations) . PerviousUrban . ImperviousUrban . Mixed Open 2010 agricultural landuseswere projectedfrom Agricultural Censusinformation (1982, 198?, 1992 and 1997)by county and accordingto methodologieschosen by individual states.Projected animal populations,to estimatemanure applications, were rooted in county Agricultural Censustrends and information from stateenvi- rorunentaland agriculturalagencies- 2010 urban landuseswere mostly projectedfrom a methodologyinvolving human populationchanges as determined by the U.S. CensusBureau for 1990and 2000and by individual stateagencies for 2010.The populationchanges were relatedto 1990 high-resolution satellite imagery of the ChesapeakeBay watershedwhich is th€ root sourceofutban andforest acreage. In the caseof Maryland,urban growth from 2000 to 2010 was determinedby Maryland Deparlmentof Natural Resourcesand the Departrnent of Planning. For all jurisdictions except Maryland and Virginia, 2010 forest and mixed open landuseswere determinedby proportioningthe net changebetween 2010 and 1990 agriculhral and urban land to 1990 mixed open and 1990 forest. Maryland and Virginia forest acreagechanges followed methodologiesor data submitted by thesestates.

.rtf pt'-nd ix C . Summaryof WatershcdModc'l Rcsults for All LoadingScenarios "f Estimatesof the number of septic systemsin the watershedin 2010 were derived from human populationprojections and people per septic system ratios from the 1990U-S. CensusBureau survey.

Point sourceswere divided into categorieswhich included: l) significantmunicipal wastewatertreatment facilities-discharging flows greaterthan or equalto 0.5 mil_ lion gallon per day;2) signihcant industriat facilities-discharging flows greater thanor equal to 0.5 million gallon per day; and 3) non,signihcantmunicipal waste_ watertreatment tircilities-discharging flows lessthan 0.5 million gallonper day and limited to facilities in Marylandand Virginia due to availabilityoidata. Point sourcenitrogen and phosphorusloads from significant and non-significant municipalwastewater treatment facilities weredetermined using flows projectedfor the year 2010 for facilities locatedin all jurisdictionsof the ChesapeakeBay watershed.These future flows were developedrnostly lrom populatior projections.Tier and E3 scenarioflows for industrialdischargers remained ar 2000 levels. Treatmenttechnologies fbr municipal facilities varied among the Tier scenariosto reachand maintainconcentrations defined under each Tier scenariodescription. The treatmenttechnologies included extendedaeration Drocessesand denitrification zones,chemical additions, additional clarificarion trnk.. d."p bed denitrification filters and micro-filtration. For industrial dischargers,site specific informationon reductionsby facility was obtainedvia phoneconlacts or site visits. Atmosphericdeposition to the ChesapeateBay watershedand tidal surfacewaters for all Tier and E3 scenariosemployed deposition data from the RegionalAcid DepositionModel (RADM), which also providesdeposition estimates representing currentconditions used tbr Progressmodel runs.

2O1OTIER 1 SCENARIO

2010 Tier I BMP implementationlevsls were generallydetermined by continuing current levelsof effort and cost-sharein eachChesapeake Bay watershedjurisdic_ tion. In addition, expected regulatory measures,jurisdictional programs and constructionschedules between 2000 and 2010 were included.

2010TIER 1 NON-PO|NTSOURCE BMps

For most non-point source BMPs, implementationrates between 1997 and 2000 were continuedto the year 2010 with limits that levelscould not exceedthe available or E3 land area to appty rhe BMps to. The scale of the calculationsis a county-segmentor the interscctionofa county political boundaryand a Chesapeake Bay watershedmodel hydrologicsegment. This is the samescale that most iurisdic_ tions report BMP implementationlevels to the Bay programoffice. Everyeffort was madeto includeBMps submittedby thejurisdictions for progress model runs into Tier l. Sincehistoric BMp datawas not availablefrom Niw iork, Delawareand WestVirginia,20l0 Tier I projectionswere determinedfrom watershed-wideimplementation rates in stateswhich employ and track the practice.

,rppr,'nr1ixa . !umm.tryof WdtcrshcdModcl Rr::ults for nil loadingSccnarios 2010 Tier I BMPs were exhapolatedfrom recent implementationrates by the landusetypes submittedby the statesfor eachBMP. For example,if a jurisdiction submits data for nutrient managementon crop land, 2010 Tier I crop land was projected and then split among high-till; low-till and hay according to relative percentages.Ifajurisdiction submitsdata as nutrientmanagement on high-till, low- till and hay individually,projections were done for eachof theselanduse categories. The 2010 Tier I scenariodoes not includetree planting on tilled land,forest conservation and forest harvesting practices. These practices are tracked by some jurisdictionsand credited in the WatershedModel for progressscenarios, but arenot part of the Tiers and E3. For forest harvestingpractices and erosionand sediment control,the wat€mhedmodel simulationdoes not accountfor addifionalloads from dishrrbed forest and construction areas, respectively' For forest conservation, planting abovewhat is removedduring developmentis accountedfor in the 2010 urbanand forestprojections. Tree planting on agriculturalland is includedin Tier I for pastureas forestbuffers since this BMP is also part ofthe Tier scenariosand E3 and pasturetree planting and pasturebuffers are treatedthe samein the model- TableC- l showsTier I watershed-wideBMP implementationlevels for all nonpoint sourceBMPs. The table designatesth€ onit of measurefor eachBMP and the relevant model landusesthat BMPs areapplied to by four major categories:agricultural, urban and mixed open, forestry and septic.As references,2000nonpoint source BMP implementationlevels are listed as well.

2O1OTIER 1 POINTSOURCE TREATMENT TECHNOLOGIES . Tier I signihcantmunicipal wastewatertteatment facilities technologies " Nitrogen Existing municipal facilities with nutrient-removal (NRI) and thoseplanned to go to NRT by 2010 areat 2010 projectedflows and 8 mg/L total nitrogen elluent concentrations(annual average) AIl remaining significantfhcilities are at 2010projected flows and2000 total nitrogeneffluent concenrauons, phosphoruse{fluent concen- " Phosphorus-2OlOprojected flows and 2000 total trations except thosetargeted in VA which are at 1.5 mgll- total phosphorus emuent concentrations(annual avtrage). . Tier I significantindustrial dischargers o 2000 flows and 2000 levels of eflluent concentrationsfor total nitrogen and total phosphorusor the permit limit effluentconcentration, whichever is less. . Tier 1 Non-signilicantmunicipal wastewater treatment facilities o 2000total nitrogenand total phosphorusetlluent concentrationsapplied to 2010 projectedflows.

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2O1OTIER 1 ATMOSPHERICDEPOSITION SOURCE CONTROLS Tier I atmosphericdeposition assumesimplementation of the 1990 Clean Air Act projected for the year 2010 with existing regulations.Air emission source controlsfor the Tier I scenarioinclude the following: . 2007 non-utility (industrial)point sourceand areasource emissions' . 2007 mobile sourceemissions with "Tier II" tail pipe standardson light duty vehicles. . 2010 utility emissionswith Title lV (Acid Rain Ptogram)fully implementedand 2O-statenitrogen oxides (NOx) stateimplementation plan (SIP) call reductionsat 0.l5 lbs/MMbtuduring the May to Septemberozone season onl'' The impactsofTier I emissionsand depositionto the ChesapeakeBay watershed's land area antl non-tidal waters are part of the reported nutrient loads from the individual landusesource categories, i-e., agriculture,urban, mixed open, forest and non-tidal surfacewaters). The reportedChesapeake Bay WatershedModel loads; however,usually do not include contributionsfrom atmosphericdeposition to tidal watersalthough the wa]r]rquality responses,as measuredby the ChesapeakeBay EstuaryModel, accountfor this sourceat levelsprescribed by Tier l-

2O1OTIER 2 SCENARIO In the deslgnof the Tier 2 scenario,considerations of the costsof BMP implementation, participationlevels and physical limitations are very limited' Tier 2 BMP levelsare consideredtechnically possible and generallydescribed below for eachof the major sourcecategory.

201OTIER 2 NON.POINTSOURCE BMPS 2010 Tier 2 BMP imptementationlevels for ion-point sourceswete generallydeter' mined by increasinglevels above Tier I by a percentageof the differencebetween Tier I and E3 levclsfor eachBMP with the percentagesbeing lower thanthose used in Tier 3. Thesepercentages were mostly prescribedby individual sourcework- groups in the ChesapeakeBay ProgramNutrient Subcommitteeand were applied watershed-wideby county-segmentsor the intersectionsof county political boundariesand the WatershedModel's segments. TableC- I showsTier 2 watershed-wideBMP implementationlevels for all nonpoint sourceBMPs. The tabledesignates the unit of measurefor eachBMB the relevant model landuses BMPs arc applied to by four major categories: agricultural, urban and mixed open,forestry and sePtic.

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For Tier 2 point sourcemunicipal facilities, technologiesto achieveg mg/L total nitrogeneflluent concentration included extended aeration processes and denitrilica- tion zones,along with chemical addition to achieve a total phosphoruseffluent concentralionof 1.0mg/L wherefacilities are not alreadyachieving these levels. . Tier 2 significantmunicipal wastewater treatment facilities o Nitrogen-All significantmunicipal facilities are at Z0l0 projectedflows and reach and maintain elTlu€nt concentrationsof g mglL (annual average) including thosefacilities that plannedto go to NRT by 2010. o Phosphorus-All significant municipal facilities are at 2010 projectedflows and reach and maintain total phosphorusemuent concentrationsof 1.0 mey'L (annualaverage) or the permit limit, whicheveris less. . Tier 2 significantindustrial dischargers " 2000 flows and generally maintain total nitrogen and phosphoruseffluent concentrationsthat are 50 percentless than thosein Tier I or the Dermitlimit. whicheveris less. . Tier 2 non-significantmunicipal \.vastewater treatment facilities o 2000 total nitrogenand total phosphoruseflluent concentrationsare appliedto 2010 projectedflows.

201OTIER 2 ATMOSPHERICDEPOSITION SOURCE CONTROLS Tier 2 almosphericdeposition assumes implementation of the 1990Clean Air Act projectedfor the year 2020 with mobile sourcecontrols beyond those in Tier L Air emissionsource controls for the Tier 2 scenarioinclude the following; . 2020 non-utilily (industrial)point sourceand areasource emissions with no arldi_ tional controlsthan Tier l. ' 2020 mobile so'rce emissionswith 2020 mobile sourceemissions with rier II tail pipe standardson light duty vehicles that are more eff€ctive than those in the Tier I scenario,as well asheavy duty dieselstandards to furtherreduce NOx emissions. . 2020 utility emissionswith Title IV (Acid Rain program)fully implementedand 20-stateNOx SIPcall reductionsat 0.15 lbVMMbtu during the May to Seprember ozoneseason only-same as Tier I controls.

The impactsof Tier 2 emissionsand resultantatmospheric deposition to the Chesa- peake Bay watershed'sland area and non-tidal waters are'part of the reported nutrientloads from lhe individual landusesource categories, i.e., agriculture,urban, mixed open, forest and non-tidal surfacewaters). The rcported ChesapeakeBay WatershedModel loads,however, usually do not includecontributions from atmos_ pheric depositionto tidal watersalthough the water quality responses,as measured by the ChesapeakeBay EstuaryModel, accountfor this sourceat levelsprescribed by Tier 2.

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2O1OTIER 3 SCENARIO

In the Tier 3 scenario,considerations of the costsof BMP implementation'participation levels and physical limitations are very limited. Tier 3 BMP levels are consideredtechnically possible and are generallydescribed below for each of the major sourcecategories.

201OTIER 3 NON-POINTSOURCE BMPS 2010 Tier 3 BMP implementationlevels for non-pointsources were generally deter' mined by increasinglevels above Tier I by a percentageof the differencebetween Tier I and E3 levelswith the percentagesbeing higherthan thoseused in Tier 2' As with Tier 2, the levelsof nonpointsource control were appliedwatershed-wide by county-segmentsor the intersectionsof county political boundariesand the Chesa- peakeBay WatershedModel's segments. TableC- l showsTier 3 watershed-wideBMP implementationlevels for all nonpoint sourceBMPs. The table designatesthe unit of measurefor eachBME the relevant model landusesBMPs are appliedto by four major categories:agricultural, urban and mixed open,forestry and septic.

201OTIER 3 POINTSOURCE TREATMENT TECHNOLOGIES For Tier 3 municipal point source facilities, heatment technologiesto achieve 5 mg/L total nitrogenemuent concentrationincluded extendedaeration processes beyondthose in Tier 2, a secondaryanoxic zoneplus methanoladdition, additional clarificationtanks and additional chemicals to achievea phosphorusetluent concentration of 0.5 mg/L total phosphorus. . Tier 3 significantmunicipal wastewater treatment facilities . Nitrogen-All significantmunicipal facilities are at 2010 projectedflow$ and reach and maintain effluent concentrationsof 5 mglL total nitrogen (annual average)including thosefacilities that plannedto go to NRT by 2010. o Phosphorus-All significant municipal facilities are at 2010 projectedflows and reachand maintain etlluent concentrationsof 0.5 mg/L total phosphorus emuent concentration(annual average) or the permit limit, whicheveris less' . Tier 3 significantindustrial dischargers total nitrogen and phosphoruseflluent " 2000 flows and generally maintain concentrationsthat are 80 percentless than thosein Tier I or the permit limit, whicheveris less. . Tier 3 non-signihcantmunicipal wastewater treatment facilities o 2000 total nitrogenand total phosphorusemuent concenfationsare appliedto 2010oroiectcd flows.

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Atmospheric deposition under the Tier 3 scenario reflects existing regulatory nitrogenoxide emissionscontrols under the 1990 Clean Air Act, as well as more aggressivebut voluntary emissionscontrols on the utility sector,projected for the year 2020. Estimatedchanges in deposition for the Tier 3 scenario reflect the following controlson nitrogenoxide emissions: . 2020 non-utility (industrial)point sourceand areasource emissions with no additional controlsthan Tiers I and 2- . 2020 mobile sourceemissions with the effect ofthe Tier II tail pipe standardson light duty vehiclesbeing felt, and the implementationof the heavy duty diesel standardsto further reduceNO, emissions.Same as Tier 2 controls.

. 2020 utility emissionswith major (90 percent)reductions in SO2and aggressive 20-stateNO^ SIP call reducrionsthrough utilities going to 0.10 lbs/MMbhrfor rhe entlr€year-no longerjust seasonal.

The impactsof emissionsand depositionto the ChesapeakeBay watershed'sland areaand non-tidalwaters under the Tier 3 scenarioare part of the reportednutri€nt loads from the individual landusesource categories (i.e., agriculture,urban, mixed open,forest, and non-tidalsurface waters). The reporledloads, however, usually do not include contributionsfrom atmosphericdeposition to tidal watersalthough the water quality responses,as measuredby the Watereuality Model, accountfor this sourceat levelsprescribed by the Tier 3 scenario.

2010 E3 SCENAR|O

BMP implementationlevels in the Tier scenarioswere boundedby levels of 83, which is specificallydesigned to takeout most of the subjectivitysurrounding what can or cannotbe achievedin controlmeasures. The particulardefinitions ofE3 BMp implementationlevels are, in part, rooted in earlier work of the ChesapeakeBay Program when a limit-of-technology condition was assessedby the Tributary StrategyWorkgroup. llowever, E3 is less subjectivethan the previous limit_of- technologyscenados in its determinationsof maximum implementationlevels. The BMP levelsin E3 are theoretical.There are no cost and few physicallimitations to implemenlingBMPs for point and non-pointsources. As discussedin Chapter4, E3 implementationlevels and their associatedreductions in nutrientsand sediment could not be achievcdfor many BMPs when consideringphysical limitationsand participationlevels. However, there are somecontrol measuresin E3 that physically could be more aggressive.The E3 conditions for these BMps were established becausea theoreticalmaximum implementationlevel would have been entirely subjective.Finally, E3 includesnew BMP technologiesand programsthat are not currently part of jurisdictional pollutant control strategies.BMp implementation levels for the E3 sc€narioare gcnerally describedbelow for nonpoint and point sourcecateqories.

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2010E3 NON-POINTSOURCE BMPs For most non-point sourceBMPs, it is assumedthat the load from every available acre of the relevant land area is being controlled by a full suite of existing or innovativepractices. In addition,management programs convert landuses from those with high-yielding nutrient and sedimentloads to those with lower yields. Table C-l showsE3 watershed-wideBMP implementationlevels for all nonpointsource BMPs. The table designatesthe unit of measurefor each BMP and the relevant model landusesthat BMPS are applied to by four major categories:agricultural, urbanand mixed open, forestryand septic.

2O1OE3 POINTSOURCE TREATMENTTECHNOLOGIES For point sourcesin E3, municipalwastewater treatment facilities reachand maintain e{fluent concentrationsof 3 mgil total nitrogen and at least 0 1 mg/L total phosphorusthrough technologies such as deep bed denitrification filters and micro-filtration. . E3 significantmunicipal wastewatertreatment facilities o Nitrogen-significant municipal facilities are at 2010 projected flows and reach and maintain total nitrogen e{Iluent concentrationsof 3 mg/L (annual average)including thosefacilities that plannedto go to NRT by 2010. o Phosphorus-significant municipal facilities are at 2010 projectedflows and reach and maintain total phosphorusefiluent concentrationsof 0.1 mg/L (annualaverage). . E3 significantindustrial dischargers . Nitrogen 2000 flows and total nitrogen eflluent concentrationsof 3 mg/L (annualaverage). " Phosphorus-2000 flows and total phosphoruseffluent concentrationsof 0.1 mg/L (annualaverage) or the permit limit, whicheveris less. . E3 non-significantmunicipal wastewatertrestment facilities o Nitrogen-Non-significant municipal facilitiesare at 2010 projectedflows and reach and maintain total nitrogen e{fluent concentrationsof 8 mg/L (annual average)- o Phosphorus-Non-significantmunicipal facilities are at 2010 projectedflows and reach and maintain total phosphoruseffluent concentrationsof 2.0 mg/L (annualaverage) or 2000 concentrations,whichever is less'

201OE3 ATMOSPHERIC DEPOSITION SOURCE CONTROLS E3 atmosphericdeposition assumesimplementation of the 1990 Clean Air Act projectedfor the year2020 with aggressivecontrols on utilities, industryand mobile sources.Air emissionsource controls for the E3 scenarioinclude the following: . 2020 non-utility (industrial)point sourceemissions cut almost in half for both SO2and NOx. ' 2020 areasource emissions that are the sameas Tiers l-3.

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. 2020 mobile sourceemissions assuming super ultra-low emissionsfor light duty vehiclesand heavyduty dieselstandards to furtherreduce NOx emissionsbeyond l rerI ano I ler J- . 2020 utility emissionswith major (90 percent)reductions in SO2and aggressive 20-stateNOx SIPcall reductionsthrough utilities going to 0.10 lbs/MMbtu for the entire year-same as Tier 3 controls.

The impactsofE3 emissionsand resultantatmospheric deposition to the Chesapeake Bay watershed'sland area and non-tidal waters are part of the reportednutrient loads from the individual landusesource categories, i.e., agriculture,urban, mixed open, forestand non-tidalsurface waters. The reportedChesapeake Bay WatershedModel loads,however, usually do not includeconhibutions from atmosphericdeposition to tidal watersalthough the water quality responses,as measuredby the Chesapeake Bay EstuaryModel, accountfor this sourceat levelsprescribed by E3.

BASINWIDE IOAD5 FOR 2OOO,TIERS 1.3 AND E3 Figures C-l through C-l depict ChesapeakeBay watershedmodeled basinwide nutrientand sedimentloads delivered to the ChesapeakeBay and its tidal tributaries by major sourcecategory for eachofthe Tier scenariosas well as 83. As references, the model estimatedloads for the year 2000 are also portrayed.

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L:iS.ptlc

E Mlred Opor

2000PiogJ.r. 2010Tler I 2010Tl.r 2 2OlOTlor 3 2010E3

Figure C-1- chesapeakeBay waterthed Model-estimated nitrogen loads delivered to the chesapeakegay and itstidal tributaries bv source.

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Figure C-3. ChesapeakeBay Watershed Model-estimated land-based tediment loads delivered to the ChesapeakeBay and itstidal tributariesby source.

.rprpcntlix ( . Srmnl.rryof W,rtrlrshcdMotlcl Rt'sults for All lo,.rdinqSccnalios As is common for reporting purposes,the model-estimateddelivered loads are a yearly averageof loadssimulated over a l0-year period (1985-1994).This removes considerationsofthe effectsofvariabl€ precipitationlevels or flows on loads.Also, nutrientloads are reported in units of million poundsper yearwhile sedimentfluxes are in million tons per year.

Load reductionsthrough the Tiersto E3 showthe impactofmost point andnon-point sourceBMPs cmployed in the design of the scenarios.For nonpoint sources,the influenceofgenerally increasingBMPs listed in TableC- l is depictedin the nurient and sedimentload reductionsfor the threerelevant source caLgories: agriculture, urban and mixed open and septic.For point sources,the impact of lower effluent concentrationsthrough the Tier to E3 yields the point sourcereductions shown in FiguresC- I andC-2.

Atmosphericdeposition to the ChesapeakeBay watershed'sland areaand non-tidal surfacewaters are part of the reportedloads but the loadsdo not includecontributions from atmosphericdeposition direct to tidal surfacewaters. In addition, the reportedloads do not reflect shorelineerosion controls employed in the scenarios. The water quality responsesas measuredby the ChesapeakeBay EstuaryModel, however,account for both atmosphericdeposition to tidal waters and shoreline erosionat levelsprescribed for the Tiers and 83.

It is important to note that landusesand animal populationschang€ considerably between2000 Progressand the Tiers and E3, which are rooted in projected2010 landusesand populations.Therefore, nutrient applications to ag,riculfuralland change considerablyover the decade.Also, the numberof septicsystems and the flows from municipalwastewater treatment facilities shift dramaticallyfrom 2000 to 2010 based on an increasingpopulation. For cxample,point sourcephosphorus loads increase l'rom 2000 to 2010 Tier I becauseof increasesin municipal facility flows which, unlike nilrogen,are not offset by technologiesto reducethis nutrientin emuents. ln additionto changesbetween 2000 andthe 2010Tier and E3 scenarios,it is imper- ative to consider landusechanges among the Tiers and,E3 due to increasing non-point sourceBMP implementationlevels. For example,sediment loads from forestedland increasethrough the Tiersto E3 becausethe land areaincreases as, for example,more and more riparianbuffers are planted on agriculturaland urbanland. In addition,increases in loadsfrom mixed openland is attributableto greateracreag€ in this categoryas, for example,agricultural land is retired.

INFLUENCEOF AIR EMISSION CONTROLSAND ATMOSPHERICDEPOSITION ON LOADS

The impactsof emissioncontrols and the resultantlower atmosoheric

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To estimatethe effectsof only ihe Tier and E3 emissioncontrols, i'e', without the influencesof otherpoint and non-pointsource BMPs, the histogramsin FigureC-4 showchanges in atmosphericdeposition ofnitrogen to the watershed'sland areaand non-tidal surface waters and the responsein delivered loads. In this model study, all landuses,fertilizer applications,point sources,septic loads and BMP implementation levels were held constantat 2000 conditions. Only atrnosphericdeposition varied. What the depositionscenarios say, for example,is "Ifprojected emissionand deposition reductionsassociated with the Tiers and E3 were realizedtoday (2000),loads to the ChesapeakeBay and its tidal tributariesare estimated to be the following." For references,reported Tier I and Tier 2 loads from the watershedare also shown in the graphics.

As canbe seenin FigureC-4, atmosphericdeposition to the watershedprogressively declines from 2000 through the Tiers to E3 as more air emission controls are includedin the model simulation.Loads from the watershedland areaand non+idal surfacewaters respond to theseprogressive emission and depositionreductions, but lo a much smdler degree. The most significantreason for the dampenedresponse is that the ChesapeakeBay watershedis about57 percentforested, or 57 percentofatmospheric deposition falls on forests.Among landuses,forests have the greatestpotential to uptakenitrogen as, generally,forests in the Bay basinare not nitrogen-sensitive.

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In the most dramatic case,atmospheric deposition of nitrogen to the watershed decreasesl7l million lbs/yearfrom 2000 to 2010 E3. If this reductionin deoosition were realizedtoday, (i.e., depositionwas to 2000 landuseswith all other present conditions),nitrogen loads to the ChesapeakeBay and its tidal tributarieswould decrease2l million lbs/yearor would be at levelsassociated with the Tier I scenario. It is importantto note that E3 levelsof emissioncontrols are consideredto be the cunent limits of technologylvith aggressivecontrols on all major sourcesof technology with aggressivecontrols on all major sourcesutilities, mobite and industrial. E3 emissioncontrols are voluntary,as opposedto regulatoryand follow the format ofdefining other E3 point and nonpointsource BMps in that implementationlevels did not considerphysical limitations, participationrates and costs.As has been describedprwiously, the intent of the Tiers is not to establishwhat can and cannot be done throughmanagement actions, either regulatoryor voluntary,as this is the responsibilityof Bay watershedjurisdictions.

LITERATURECITED

ChesapeakeBay ProgramOffice (CBPO). 200O.Chesapeake Buy ll/aterthedMotlel Lantl Use dnd Motlel Linkage,t to the Airshed dnd Estuarine Models. prepared by the Chesapeake Bay ProgramModeling Subcommittce.Annapolis, Maryland.

.r[)pcr](lix ( - 5|mm,rry of !V.rtcrshndModr:l Rr:sLrlts for Al Lo.tclinqScr:narios appenclix S Summaryof KeyWater Quality AttainmentScenarios

TableD-l. Keyscenario descriptions.

Observed 1984-1994chesapeake Bay water quality monitored condit:ons.

Progress2000 Model estimatedconditions tesuJt;ng trom implementationof BMPsand treatment technologies anolace in 2000

Tier1 Modelestimated condition5 resulting lrom implementationof Tier1 BMPsand treatment technologyimplementation levels.

Tier 2 Modelestimated condition5 resulting from implementationof Tier2 BMPsand treatment technologyimplementation levels.

er l Modelestimated conditions resulting from implementationof Tier3 BMPsand t.eatment technologyimplementation levels; sdme as option 3 cap loadallocation.

Tier3 + 207o Tier3 modelestimated conditions plu5 a 2Opercent reduction in thoreline/nearshore sedimentloads.

Tier3 + 50% Tier3 modelestimated conditions plus a 50 percentreduction in shoreline/nearshore sedimentloads.

Option4 Option4 cap loadallocation model estimated conditions

Conlirm confirmationof agreedto nutrientand sedimentcap loadallocations model estimated conditions.

Confirm+ 10 confirmationscenario model estimated conditions plus a l0 percentreduction in shoreline/nearshoresediment loads,

Confirm+ 20 confirmationscenario model estimated conditions plus a 20 percentreduction in shoreline/nearshoresediment loads.

Allocation Selectedcap loadallocation option (175 million pounds nitrogen/l2.8 million pounds phosphorus)model estimated conditions.

OptionI oDtion1 cao loadallocation model estimated conditions

upron ) Option5 cap loadallocation model estimated conditions

E3 E3s(enario model estimated conditions.

All Forest All Jorestedwatershed scenario model estimated conditions.

Pristine Pristinewatershed scenario model estimated conditions.

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