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Citizens Advisory Committee State College, Pennsylvania August 13, 2004

Citizens Advisory Committee State College, Pennsylvania August 13, 2004. Susquehanna Sediments. Historic highs: 9 million tons per year Current transported load: 3.1 m/tons Lower Susq dams: 50-70% trapping efficiency Net delivered load to Bay: .9 to 1.1 m/tons

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Citizens Advisory Committee State College, Pennsylvania August 13, 2004

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  1. Citizens Advisory Committee State College, Pennsylvania August 13, 2004

  2. Susquehanna Sediments • Historic highs: 9 million tons per year • Current transported load: 3.1 m/tons • Lower Susq dams: 50-70% trapping efficiency • Net delivered load to Bay: .9 to 1.1 m/tons • Net delivered load 1985: 1.178 m/tons • Net delivered load 2002: 1.060 m/tons

  3. 3,100,000 tons sediment AVERAGE ANNUAL 75,000 tons nitrogen INPUT TO RESERVOIR SYSTEM 4,350 tons phosphorus Percentage trapped in reservoir system: Safe Harbor Dam SEDIMENT 70% Holtwood Dam 2% AVERAGE ANNUAL NITROGEN AMOUNT TRAPPED IN RESERVOIR SYSTEM 2,210,000 tons sediment (70%) Conowingo Dam 1,500 tons nitrogen (2%) 1,740 tons phosphorus (40%) 40% PHOSPHORUS 890,000 tons sediment AVERAGE ANNUAL 73,500 tons nitrogen OUTPUT TO CHESAPEAKE BAY 2,610 tons phosphorus

  4. Storage Capacity Status • Conventional estimate 17-20 years • With assumptions: 20-30 years 1. 10% decrease in transported load 2. Statistically expected scour 3. Trapping efficiency of 60%

  5. 1985 Sediment Loads • Bay-wide: 5.8 m/tons • Susquehanna: 1.2 m/tons (20%) • James River: 1.3 m/tons (22%) • Potomac: 2.0 m/tons (35%)

  6. 2010 Cap Load Allocations • Bay-wide: 4.15 m/tons • Susquehanna: 0.96 m/tons • James River: 0.94 m/tons • Potomac: 1.49 m/tons

  7. Moving Forward • C2K: “By 2003, work with the SRBC and others to adopt and begin implementing strategies that prevent the loss of the sediment retention capabilities of the lower Susquehanna River dams.” • Pennsylvania tributary strategy: 1.1 m/tons with full implementation

  8. Lingering Issues • Reservoir feasibility study • What about the wild cards? - scour - episodic nature of precip - flow and bank loss - system storage and the great purge • Stay the course, but manage expectations

  9. The Water Quantity-C2K Connection:The Implications of Flow for Water Quality and Vital Habitat Protection and Restoration

  10. Basin Overview • 27,510 square mile watershed. • 32,000+ miles of streams. • Normal Flow of Susquehanna River is 18 million gallons per minute at Havre de Grace, MD. • Susquehanna River is largest tributary to Chesapeake Bay. • Population of 4.2 million

  11. Project Review Regulations • Consumptive Water Use > 20,000 gpd • Surface-Water Withdrawals > 100,000 gpd • Ground-Water Withdrawals > 100,000 gpd

  12. Surface-Water Withdrawals • Regulatory threshold; 100,000 gpd • Protection of instream/downstream uses • Conservation releases • Passby flow requirements • Cold water fisheries – IFIM analysis • Warm water fisheries – 20 % ADF

  13. Groundwater in the Susquehanna Basin • Nearly 69 billion gallons. • Most of the potable water is within 300 ft of ground surface. • Groundwater supplies stream flow, upwards of 90% of base flow during extended droughts. • Withdrawing groundwater results in about a 1-to-1 reduction in flow downstream.

  14. Drought Years • 1991 • 1995 • 1997 • 1998 • 1999 • 2002

  15. Groundwater in the Susquehanna Basin • Over 50% of the basin’s population uses groundwater for water supply • To date, SRBC has approved the withdrawal of more than 232 million gpd of groundwater.

  16. Groundwater Use in the Susquehanna Basin (1995 data) • Water Supply 195 mgd = 50% • Mining 90 “ = 23% • Industrial 48 “ = 12% • Agriculture 42 “ = 11% • Other 16 “ = 4% • Total 391 mgd

  17. Ground-Water Withdrawals • Regulatory threshold; 100,000 gpd • Avoid impacts to resource and other users • Pump test guidance • Ground-water availability analysis • 48-hour constant-rate pump test

  18. Consumptive Water Use • Regulatory threshold; 20,000 gpd • Water used and not returned to the basin • Out-of-basin diversions • Compensation requirements

  19. Compensation Options For Consumptive Water Use • Discontinuance • Releases from storage • Payment into the Water Management Fund • 30,000 acre/ft of pooled water storage

  20. Moving Forward • Warm Water IFIM • Groundwater Management Plan • PA Act 220 State Water Plan • Water Budgeting • Protected Area Designations

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