Occoquan and Dulles Occoquan and Dulles PoliciesPolicies

Potomac DWSP PartnershipPotomac DWSP PartnershipMeetingMeeting

February 21, 2008February 21, 2008

An Overview of:An Overview of:

• The Occoquan Policy The Occoquan Policy

• Occoquan Watershed Monitoring Occoquan Watershed Monitoring Laboratory (OWML)Laboratory (OWML)

• Occoquan Non-Point Source Program Occoquan Non-Point Source Program

• Dulles PolicyDulles Policy

Special Water Quality Standards in Special Water Quality Standards in VirginiaVirginia

Reservoirs and Service AreasReservoirs and Service Areas

Watershed FactsWatershed Facts• Area: 592 Square MilesArea: 592 Square Miles• Streams: 1,300 MilesStreams: 1,300 Miles• Major impoundments:Major impoundments:

– Lake ManassasLake Manassas– Lake JacksonLake Jackson– Occoquan ReservoirOccoquan Reservoir

• Land Use (estimate):Land Use (estimate):– 14% Low Density Residential14% Low Density Residential– 8% Medium and High Density Residential8% Medium and High Density Residential– 4% Commercial and Industrial4% Commercial and Industrial– 1% Institutional1% Institutional– 13% Agricultural13% Agricultural– 9% Pasture9% Pasture– 51% Forest and Idle51% Forest and Idle

• Residents: 390,000 (estimate)Residents: 390,000 (estimate)

Source: OWML -1998, NVRC - 2000, 2005

The ProblemThe Problem• Late 1960s – WQ problems in the Occoquan Reservoir:Late 1960s – WQ problems in the Occoquan Reservoir:

– Massive algal bloomsMassive algal blooms– Periodic episodes of taste and odors in drinking waterPeriodic episodes of taste and odors in drinking water– Shortened filter runs due to clogging during periods of high Shortened filter runs due to clogging during periods of high

algal growthalgal growth– Periodic fish kills due to oxygen depletionPeriodic fish kills due to oxygen depletion– Hypolimnetic de-oxygenation due to accumulation of organic Hypolimnetic de-oxygenation due to accumulation of organic

material in the sedimentsmaterial in the sediments

• The State Water Control Board (Board) commissioned a The State Water Control Board (Board) commissioned a Study to recommend a course of action to preserve the Study to recommend a course of action to preserve the Occoquan as a valuable water resource for future Occoquan as a valuable water resource for future generations. generations.

• The Study results stated that point source pollution was The Study results stated that point source pollution was the primary cause of water quality degradation the primary cause of water quality degradation

• A high degree of waste treatment would be necessary to A high degree of waste treatment would be necessary to prolong the life of the drinking water supply. prolong the life of the drinking water supply.

Summer 1973 – Algal Bloom (Source: OWML)Summer 1973 – Algal Bloom (Source: OWML)

The Policy The Policy 11

• Formed UOSA (Upper Occoquan Sewage Formed UOSA (Upper Occoquan Sewage Authority) to Consolidate Older WWTPsAuthority) to Consolidate Older WWTPs

• Established Occoquan Watershed Monitoring Established Occoquan Watershed Monitoring ProgramProgram

• Established Indirect Potable Reuse as Sustainable Established Indirect Potable Reuse as Sustainable Water Supply for Northern VirginiaWater Supply for Northern Virginia

• Regulation administered by Virginia Department Regulation administered by Virginia Department of Environmental Quality (VDEQ)of Environmental Quality (VDEQ)

1 A Policy for Waste Treatment and Water Quality Management in the Occoquan Watershed

Policy Requirements – WWTP Policy Requirements – WWTP PlantsPlants• Preferably only two high-performance regional Preferably only two high-performance regional

plantsplants• All point sources preferably 20 stream miles from All point sources preferably 20 stream miles from

Fairfax Water intakeFairfax Water intake• Incremental increases in regional plant capacity Incremental increases in regional plant capacity

must be approved based on results of the must be approved based on results of the monitoring programmonitoring program

• All future plants must meet or exceed UOSA All future plants must meet or exceed UOSA design standardsdesign standards

Policy Requirement - Policy Requirement - EffluentEffluent• Discharge Limits:Discharge Limits:

– COD (mg/l) - 10.0 COD (mg/l) - 10.0 – Suspended solids (mg/l) - 1.0 Suspended solids (mg/l) - 1.0 – Nitrogen (mg/l) - 1.0 (as TKN) Nitrogen (mg/l) - 1.0 (as TKN) – Phosphorus (mg/l) - 0.1 Phosphorus (mg/l) - 0.1 – MBAS (mg/l) - 0.1 MBAS (mg/l) - 0.1 – Turbidity (NTU) - 0.5 Turbidity (NTU) - 0.5 – Coliform per 100 ml Sample - less than Coliform per 100 ml Sample - less than

2.02.0

UOSA Process Treatment (from OWML)UOSA Process Treatment (from OWML)

Policy Requirement – Policy Requirement – Wastewater OperationWastewater OperationAll pumping stations in the watershed must have:All pumping stations in the watershed must have:

– Stand-by pumping unitsStand-by pumping units– At least one “on-site” back-up power supplyAt least one “on-site” back-up power supply– At least one “off-site” back-up power supplyAt least one “off-site” back-up power supply– Be designed so that no single failure of a mechanical or Be designed so that no single failure of a mechanical or

electrical component could degrade pumping capabilityelectrical component could degrade pumping capability– Have pumps and valves arranges so that these units can be Have pumps and valves arranges so that these units can be

removed and replaced without by-pass pumpingremoved and replaced without by-pass pumping– Have retention basins of minimum one-day capacityHave retention basins of minimum one-day capacity– Have flow measurement devices Have flow measurement devices

• Nitrate removal required when NOx conc. Reach 5 mg/l at Nitrate removal required when NOx conc. Reach 5 mg/l at IntakeIntake

Policy Requirement – Collection Policy Requirement – Collection SystemsSystems

• Certified and submitted to Board – Certified and submitted to Board – Inflow/Infiltration (I/I) limited to 100 gal/inch-Inflow/Infiltration (I/I) limited to 100 gal/inch-dia/mile/daydia/mile/day

• Approved pre-treatment programApproved pre-treatment program

• Up-to-date and maintained (subject to annual Up-to-date and maintained (subject to annual inspection) electrical and fluid system inspection) electrical and fluid system diagramsdiagrams

• Detailed as-built and installed drawingsDetailed as-built and installed drawings

Occoquan Watershed Occoquan Watershed Monitoring ProgramMonitoring Program

• Occoquan Watershed Monitoring Occoquan Watershed Monitoring Lab (OWML)Lab (OWML)– Sampling and AnalysisSampling and Analysis– Stream Gages and Reservoir Stream Gages and Reservoir

StationsStations• Overseen by Occoquan Watershed Overseen by Occoquan Watershed

Monitoring SubcommitteeMonitoring Subcommittee• Objective: to Ensure that Objective: to Ensure that

performance levels are performance levels are maintained and that the effects of maintained and that the effects of pointpoint and and non-pointnon-point sources are sources are knownknown

Occoquan NPS ProgramsOccoquan NPS Programs

• Technical Investigations and SupportTechnical Investigations and Support– Northern Virginia BMP HandbookNorthern Virginia BMP Handbook– Nonstructural Urban BMP HandbookNonstructural Urban BMP Handbook– Land Use Inventory and UpdatesLand Use Inventory and Updates

• Fairfax County Water Supply Overlay Fairfax County Water Supply Overlay DistrictDistrict

• Historic Fairfax County Down-zoning to Historic Fairfax County Down-zoning to Protect Occoquan ReservoirProtect Occoquan Reservoir

• Occoquan NPS ModelOccoquan NPS Model

SummarySummary

• Occoquan Policy was a milestone in Occoquan Policy was a milestone in Water Quality Management in the Water Quality Management in the Commonwealth of VirginiaCommonwealth of Virginia

• Water Quality improved dramatically Water Quality improved dramatically after UOSA came on-lineafter UOSA came on-line

• Reservoir Water Quality has Reservoir Water Quality has remained stable for decadesremained stable for decades

Special Water Quality Standards in Special Water Quality Standards in VirginiaVirginia

SWCB Adopts in 1971 (revised

1981 and 1991)

UOSA on-line in 1978

SWCB Adopts in 1975 (revised in

2004)

LCSA Broad Run WRF on-line soon

Evolution of Dulles PolicyEvolution of Dulles Policy

• Wastewater issues of 1970sWastewater issues of 1970s

• Adopted by SWCB in 1975 as a Adopted by SWCB in 1975 as a ‘planning’ document for regional ‘planning’ document for regional sewage treatment in northwestern sewage treatment in northwestern Fairfax and eastern Loudoun Fairfax and eastern Loudoun CountiesCounties

• Policy revised in 2004 to update for Policy revised in 2004 to update for new LCSA Water Reclamation facilitynew LCSA Water Reclamation facility

Dulles Policy – Regional Dulles Policy – Regional PlantsPlants• Limits Regional Plants to 2Limits Regional Plants to 2• Discharge in the Broad Run and Goose Creek Discharge in the Broad Run and Goose Creek

WatershedsWatersheds• No discharges within 10 stream miles upstream No discharges within 10 stream miles upstream

from Water Supply Intakesfrom Water Supply Intakes• High-performance effluent requirements based on High-performance effluent requirements based on

Occoquan PolicyOccoquan Policy• Nitrate removal required when NOx conc. reach 5 Nitrate removal required when NOx conc. reach 5

mg/l at Intakemg/l at Intake• LCSA and Fairfax Water to coordinate monitoring LCSA and Fairfax Water to coordinate monitoring

programprogram

Collaborative Updates (2000-Collaborative Updates (2000-2004)2004)

• DAWP Stakeholder Meetings: FW, DAWP Stakeholder Meetings: FW, LCSA, Fairfax Co., VDEQ, OWML, LCSA, Fairfax Co., VDEQ, OWML, VDH, NVRC, City of LeesburgVDH, NVRC, City of Leesburg

• Craft reasonable and protective Craft reasonable and protective Policy modificationsPolicy modifications

• Objective: Ensure Protection of FW Objective: Ensure Protection of FW IntakeIntake

Dulles Policy Revisions Dulles Policy Revisions (2004)(2004)

• Effluent Quality Limits for COD, TKN, Effluent Quality Limits for COD, TKN, TP, Turbidity, Coliform (now E.Coli TP, Turbidity, Coliform (now E.Coli limit), and TSS – same as Occoquan limit), and TSS – same as Occoquan PolicyPolicy

• Collaborative process was successfulCollaborative process was successful

Questions?Questions?