Occoquan and Dulles Policies

1. Occoquan and Dulles Policies Potomac DWSP Partnership Meeting February 21, 2008

2. An Overview of: • The Occoquan Policy • Occoquan Watershed Monitoring Laboratory (OWML) • Occoquan Non-Point Source Program • Dulles Policy

3. Special Water Quality Standards in Virginia

4. Reservoirs and Service Areas

5. Watershed Facts • Area: 592 Square Miles • Streams: 1,300 Miles • Major impoundments: • Lake Manassas • Lake Jackson • Occoquan Reservoir • Land Use (estimate): • 14% Low Density Residential • 8% Medium and High Density Residential • 4% Commercial and Industrial • 1% Institutional • 13% Agricultural • 9% Pasture • 51% Forest and Idle • Residents: 390,000 (estimate) Source: OWML -1998, NVRC - 2000, 2005

6. The Problem • Late 1960s – WQ problems in the Occoquan Reservoir: • Massive algal blooms • Periodic episodes of taste and odors in drinking water • Shortened filter runs due to clogging during periods of high algal growth • Periodic fish kills due to oxygen depletion • Hypolimnetic de-oxygenation due to accumulation of organic material in the sediments • The State Water Control Board (Board) commissioned a Study to recommend a course of action to preserve the Occoquan as a valuable water resource for future generations. • The Study results stated that point source pollution was the primary cause of water quality degradation • A high degree of waste treatment would be necessary to prolong the life of the drinking water supply.

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

8. The Policy 1 1 A Policy for Waste Treatment and Water Quality Management in the Occoquan Watershed • Formed UOSA (Upper Occoquan Sewage Authority) to Consolidate Older WWTPs • Established Occoquan Watershed Monitoring Program • Established Indirect Potable Reuse as Sustainable Water Supply for Northern Virginia • Regulation administered by Virginia Department of Environmental Quality (VDEQ)

9. Policy Requirements – WWTP Plants • Preferably only two high-performance regional plants • All point sources preferably 20 stream miles from Fairfax Water intake • Incremental increases in regional plant capacity must be approved based on results of the monitoring program • All future plants must meet or exceed UOSA design standards

10. Policy Requirement - Effluent • Discharge Limits: • COD (mg/l) - 10.0 • Suspended solids (mg/l) - 1.0 • Nitrogen (mg/l) - 1.0 (as TKN) • Phosphorus (mg/l) - 0.1 • MBAS (mg/l) - 0.1 • Turbidity (NTU) - 0.5 • Coliform per 100 ml Sample - less than 2.0

11. UOSA Process Treatment (from OWML)

12. Policy Requirement – Wastewater Operation All pumping stations in the watershed must have: • Stand-by pumping units • At least one “on-site” back-up power supply • At least one “off-site” back-up power supply • Be designed so that no single failure of a mechanical or electrical component could degrade pumping capability • Have pumps and valves arranges so that these units can be removed and replaced without by-pass pumping • Have retention basins of minimum one-day capacity • Have flow measurement devices • Nitrate removal required when NOx conc. Reach 5 mg/l at Intake

13. Policy Requirement – Collection Systems • Certified and submitted to Board – Inflow/Infiltration (I/I) limited to 100 gal/inch-dia/mile/day • Approved pre-treatment program • Up-to-date and maintained (subject to annual inspection) electrical and fluid system diagrams • Detailed as-built and installed drawings

14. Occoquan Watershed Monitoring Program • Occoquan Watershed Monitoring Lab (OWML) • Sampling and Analysis • Stream Gages and Reservoir Stations • Overseen by Occoquan Watershed Monitoring Subcommittee • Objective: to Ensure that performance levels are maintained and that the effects of point and non-point sources are known

15. Occoquan NPS Programs • Technical Investigations and Support • Northern Virginia BMP Handbook • Nonstructural Urban BMP Handbook • Land Use Inventory and Updates • Fairfax County Water Supply Overlay District • Historic Fairfax County Down-zoning to Protect Occoquan Reservoir • Occoquan NPS Model

16. Summary • Occoquan Policy was a milestone in Water Quality Management in the Commonwealth of Virginia • Water Quality improved dramatically after UOSA came on-line • Reservoir Water Quality has remained stable for decades

17. Special Water Quality Standards in Virginia SWCB Adopts in 1975 (revised in 2004) LCSA Broad Run WRF on-line soon SWCB Adopts in 1971 (revised 1981 and 1991) UOSA on-line in 1978

18. Evolution of Dulles Policy • Wastewater issues of 1970s • Adopted by SWCB in 1975 as a ‘planning’ document for regional sewage treatment in northwestern Fairfax and eastern Loudoun Counties • Policy revised in 2004 to update for new LCSA Water Reclamation facility

19. Dulles Policy – Regional Plants • Limits Regional Plants to 2 • Discharge in the Broad Run and Goose Creek Watersheds • No discharges within 10 stream miles upstream from Water Supply Intakes • High-performance effluent requirements based on Occoquan Policy • Nitrate removal required when NOx conc. reach 5 mg/l at Intake • LCSA and Fairfax Water to coordinate monitoring program

20. Collaborative Updates (2000-2004) • DAWP Stakeholder Meetings: FW, LCSA, Fairfax Co., VDEQ, OWML, VDH, NVRC, City of Leesburg • Craft reasonable and protective Policy modifications • Objective: Ensure Protection of FW Intake

21. Dulles Policy Revisions (2004) • Effluent Quality Limits for COD, TKN, TP, Turbidity, Coliform (now E.Coli limit), and TSS – same as Occoquan Policy • Collaborative process was successful

22. Questions?