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USACE Managing a Drought

USACE Managing a Drought. Overview Timeline Depletion Scenario. Current Status– 17 Oct 07. Current Conditions. Winter Outlook. 2006-2008 Drought. Lake Lanier. 1,040 mi 2 Drainage Area 105 MW 1,087,060 Acre-Feet 750 cfs Minimum Flow at Peachtree Creek. Lake Lanier.

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USACE Managing a Drought

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  1. USACE Managing a Drought • Overview • Timeline • Depletion Scenario Current Status– 17 Oct 07

  2. Current Conditions

  3. Winter Outlook

  4. 2006-2008 Drought

  5. Lake Lanier • 1,040 mi2 Drainage Area • 105 MW • 1,087,060 Acre-Feet • 750 cfs Minimum Flow at Peachtree Creek

  6. Lake Lanier 14 ½ - feet below Summer Pool

  7. West Point • 3,440 mi2 Drainage Area • 80 MW • 306,131 Acre-Feet

  8. West Point 13 – feet below Summer Pool

  9. W. F. George • 7,460 mi2 Drainage Area • 145 MW • 244,400 Acre-Feet

  10. W. F. George 5 - feet below Summer Pool

  11. Operations During Drought Conditions • Lake levels fall due to declining inflows in basin • Rainfall forecasts indicate dry conditions ahead • State, Federal, local agencies, and stakeholders notified of drought • Press releases issued to public periodically • Discharges are reduced according to Water Control Plan • Navigation reduced and curtailed as conditions worsen • Lakes and basin inflows continue to decline, and recreational uses are impacted. • Releases specifically for hydropower reduced

  12. Operations During Drought Conditions (continued) • Releases from dams made to support water supply and water quality (WS/WQ) • Releases for WS/WQ made through turbines providing limited hydropower • SEPA may purchase replacement energy to fulfill contract • Flow reduced from lower basin projects to meet minimum flow requirements • Water to meet downstream minimum flow requirements draws from project storage thus lowering lake levels. • Coordination made with fishery agencies to facilitate fish spawn operations during low water periods

  13. Drought Scenario • Average inflow for ACF basin in May is 40% of normal. Releases from Buford Dam for water supply and water quality needs in Atlanta only. Releases are made thru turbine in most efficient and cost effective means. • Lanier reaches peak elevation of 1065.9 in May. • Average inflow in June is 25% of normal. Releases from Buford averages 830 cfs in June. • Average inflow in July is 29% of normal. Releases from Buford averages 930 cfs in July. • Average inflow in August is 21% of normal. Releases from Buford averages 1070 cfs. Increases are due to evaporation, increased summer withdrawals, and dry conditions in basin. Lanier’s level continues to decline. 5 2 Lake level at Lanier 5 1 3 4 Releases from Buford Dam

  14. Drought Scenario continued Lake level at West Point Lake level at George Woodruff discharge 1 2 3 4 5 • Rainfall event in early May causes rise in lakes. Head limits at George and Woodruff prompt increased releases. • In June, lakes at summer level. Releases from Woodruff reduced from 6100 cfs to 5500 cfs. • ACF basin inflow averages 4500 cfs (26% of normal) in July. Lakes continue to decline due to water drawn from storage to supplement Apalachicola flow. • Rainfall in basin above Woodruff and head limits require increase in discharge. Other lakes continue to decline at slower rate. • Conditions worsen in August and flow reduced to 5000 cfs from Woodruff. Lakes continue to decline. Basin average inflow is 2500 cfs. Half of 5000 cfs minimum must come from storage. 1 3 2 4 5 1 2 3 4 5 During summer months as conditions change, notification is made to impacted stakeholders and public via basin drought calls, web page, newsletter, press releases and other means.

  15. Up to 1,500 cfs release from Lake Lanier is required to meet Metro-Atlanta water supply withdrawals plus to insure 750 cfs remains in river to meet water quality standards at Peachtree Creek. 750 cfs Flow Required for Water Quality Water supply withdrawal Local tributary inflow Lake LanierMinimum Flow Requirements

  16. Revised Interim Operation Plan • Year-round operations to support flow needs for sturgeon spawning, young sturgeon, mussels, and host fish for mussels • Minimize or avoid impacts of low flow operations on listed species or critical habitat • Provide for storage when water is more plentiful to allow for future augmentation during low flows in support of mussels • Minimize conflicts with management for other fish and wildlife species (e.g., reservoir fish management) • Minimize impact to other project purposes

  17. 2007 2008 01 June 08, RIOP 05 Sep 06, IOP 28 Feb 07, RPM3 6500 cfs 15 Nov 07, EDO for the IOP 16 May 07, Volumetric Balancing TS Fay Difference in location of storage in 2007 vs. 2008

  18. ACF System Storage Conservation storage at West Point & W. F. George close to depleted Lake Lanier holds most of remaining basin storage

  19. Return to Normal Operations Enter Drought Ops 5,000 cfs 4,500 cfs Drought Zone, Flow < 5,000

  20. 5,000 cfs Flow Target Flow to Apalachicola River Water released from lake storage Basin Inflow * Inflows to ACF basin * * Total basin inflow to ACF basin minus reservoir evaporation and municipal, industrial, and agricultural consumption.

  21. Engage stakeholders via bi-weekly teleconferences • Stakeholder Awareness • Improve Data Dissemination • Communication is key !!! • Improved Water Management Tools • National Focus on ACF

  22. Water Management The Future…

  23. Questions?

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