USACE Managing a Drought

USACE Managing a Drought

Overview Timeline Depletion Scenario

Current Status– 17 Oct 07

Current Conditions Current Conditions

Winter Outlook Winter Outlook

2006-2008 Drought

Lake LanierLake Lanier

1,040 mi2 Drainage Area 105 MW 1,087,060 Acre-Feet 750 cfs Minimum Flow

at Peachtree Creek

Lake LanierLake Lanier

14 ½ - feet below Summer Pool

West PointWest Point

3,440 mi2 Drainage Area 80 MW 306,131 Acre-Feet

West PointWest Point

13 – feet

below Summer Pool

W. F. GeorgeW. F. George

7,460 mi2 Drainage Area 145 MW 244,400 Acre-Feet

W. F. GeorgeW. F. George

5 - feet below

Summer Pool

  Operations During Drought ConditionsOperations During Drought Conditions☼ Lake levels fall due to declining inflows in basinLake levels fall due to declining inflows in basin

☼ Rainfall forecasts indicate dry conditions aheadRainfall forecasts indicate dry conditions ahead

☼ State, Federal, local agencies, and stakeholders notified of droughtState, Federal, local agencies, and stakeholders notified of drought

☼ Press releases issued to public periodicallyPress releases issued to public periodically

☼ Discharges are reduced according to Water Control PlanDischarges are reduced according to Water Control Plan

☼ Navigation reduced and curtailed as conditions worsenNavigation reduced and curtailed as conditions worsen

☼ Lakes and basin inflows continue to decline, and recreational uses are Lakes and basin inflows continue to decline, and recreational uses are impacted.impacted.

☼ Releases specifically for hydropower reducedReleases specifically for hydropower reduced

  

Operations During Drought ConditionsOperations During Drought Conditions(continued)(continued)

☼ Releases from dams made to support water supply and water quality Releases from dams made to support water supply and water quality (WS/WQ) (WS/WQ)

☼ Releases for WS/WQ made through turbines providing limited Releases for WS/WQ made through turbines providing limited hydropowerhydropower

☼ SEPA may purchase replacement energy to fulfill contractSEPA may purchase replacement energy to fulfill contract☼ Flow reduced from lower basin projects to meet minimum flow Flow reduced from lower basin projects to meet minimum flow requirementsrequirements

☼ Water to meet downstream minimum flow requirements draws from Water to meet downstream minimum flow requirements draws from project storage thus lowering lake levels.project storage thus lowering lake levels.

☼ Coordination made with fishery agencies to facilitate fish spawn Coordination made with fishery agencies to facilitate fish spawn operations during low water periodsoperations during low water periods

Drought ScenarioDrought Scenario

1.1. Average inflow for ACF basin in May is 40% of normal. Releases from Buford Dam for water 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 supply and water quality needs in Atlanta only. Releases are made thru turbine in most efficient and cost effective means.and cost effective means.

2.2. Lanier reaches peak elevation of 1065.9 in May. Lanier reaches peak elevation of 1065.9 in May.

3.3. Average inflow in June is 25% of normal. Releases from Buford averages 830 cfs in June.Average inflow in June is 25% of normal. Releases from Buford averages 830 cfs in June.

4.4. Average inflow in July is 29% of normal. Releases from Buford averages 930 cfs in July.Average inflow in July is 29% of normal. Releases from Buford averages 930 cfs in July.

5.5. Average inflow in August is 21% of normal. Releases from Buford averages 1070 cfs. Increases 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 are due to evaporation, increased summer withdrawals, and dry conditions in basin. Lanier’s level continues to decline.level continues to decline.

Lake level at LanierLake level at Lanier

Releases from Buford DamReleases from Buford Dam

11 554433

2255

Woodruff dischargeWoodruff discharge

Lake level at West PointLake level at West Point

Lake level at GeorgeLake level at George

Drought Scenario Drought Scenario continued continued

1.1. Rainfall event in early May causes Rainfall event in early May causes rise in lakes. Head limits at George rise in lakes. Head limits at George

and Woodruff prompt increased and Woodruff prompt increased releases.releases.

2.2. In June, lakes at summer level. In June, lakes at summer level. Releases from Woodruff reduced Releases from Woodruff reduced

from 6100 cfs to 5500 cfs. from 6100 cfs to 5500 cfs.

3.3. ACF basin inflow averages 4500 cfs ACF basin inflow averages 4500 cfs (26% of normal) in July. Lakes (26% of normal) in July. Lakes continue to decline due to water continue to decline due to water

drawn from storage to supplement drawn from storage to supplement Apalachicola flow.Apalachicola flow.

4.4. Rainfall in basin above Woodruff Rainfall in basin above Woodruff and head limits require increase in and head limits require increase in discharge. Other lakes continue to discharge. Other lakes continue to

decline at slower rate.decline at slower rate.

5.5. Conditions worsen in August and Conditions worsen in August and flow reduced to 5000 cfs from flow reduced to 5000 cfs from Woodruff. Lakes continue to Woodruff. Lakes continue to

decline. Basin average inflow is decline. Basin average inflow is 2500 cfs. Half of 5000 cfs minimum 2500 cfs. Half of 5000 cfs minimum

must come from storage.must come from storage.

11

22 44

33

33

22

55

5533

55

11

1144

44

22

During summer months as conditions During summer months as conditions change, notification is made to impacted change, notification is made to impacted

stakeholders and public via stakeholders and public via basin drought basin drought callscalls, , web pageweb page, newsletter, , newsletter, press releasespress releases

and other means.and other means.

Lake LanierMinimum Flow Requirements

Lake LanierMinimum Flow Requirements

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.

Water supply withdrawalWater supply withdrawal

Local tributary inflowLocal tributary inflow

750 cfs Flow Required for Water Quality

• Year-round operations to support flow needs for Year-round operations to support flow needs for sturgeon spawning, young sturgeon, mussels, and host sturgeon spawning, young sturgeon, mussels, and host fish for musselsfish for mussels

• Minimize or avoid impacts of low flow operations on Minimize or avoid impacts of low flow operations on listed species or critical habitatlisted species or critical habitat

• Provide for storage when water is more plentiful to Provide for storage when water is more plentiful to allow for future augmentation during low flows in allow for future augmentation during low flows in support of musselssupport of mussels

• Minimize conflicts with management for other fish and Minimize conflicts with management for other fish and wildlife species (e.g., reservoir fish management)wildlife species (e.g., reservoir fish management)

• Minimize impact to other project purposesMinimize impact to other project purposes

Revised Interim Operation Plan

ACF Conservation Storage

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

Co

nse

rvat

ion

Sto

rag

e, (

ac-f

t)

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

Top of Conservation

Drought Zone

Composite Zone 3

Composite Zone 2

Composite Zone 1

Lake Lanier

West Point

Add value of 1,856,000 acre-ft to obtain total composite storage.

West Point

Lake Lanier

Wal

ter F. G

eorg

e

Walte

r F. Georg

e

Composite Zone 4

2008200820072007

01 June 08, RIOP01 June 08, RIOP

15 Nov 07, EDO for the IOP15 Nov 07, EDO for the IOP

05 Sep 06, IOP05 Sep 06, IOP28 Feb 07, RPM3 6500 cfs28 Feb 07, RPM3 6500 cfs

16 May 07, Volumetric Balancing16 May 07, Volumetric Balancing

TS FayTS Fay

Difference in location of storage in 2007 vs. 2008Difference in location of storage in 2007 vs. 2008

ACF System StorageACF System Storage

Lake Lanier holds most of remaining basin storage

Conservation storage at West Point & W. F. George close to depleted

Drought Zone, Flow < 5,000Drought Zone, Flow < 5,000 4,500 cfs4,500 cfs

Enter Drought OpsEnter Drought Ops

5,000 cfs5,000 cfs

Return to Normal OperationsReturn to Normal Operations

5,000 cfs Flow Target5,000 cfs Flow Target

Inflows to ACF basin *

Water released from lake storage

Flow to Apalachicola River

Basin Inflow *

* Total basin inflow to ACF basin minus reservoir evaporation and municipal, industrial, and agricultural consumption.

• Engage stakeholders via bi-weekly

teleconferences

• Stakeholder Awareness

• Improve Data Dissemination

• Communication is key !!!

• Improved Water Management Tools

• National Focus on ACF

Water ManagementWater ManagementThe Future…The Future…

Questions?Questions?