USACE Savannah District Water Management Overview
AGENDA Welcome Current Basin Status Seasonal Forecast Water Management Overview Questions
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Past Year’s Rainfall and Levels Hartwell Reservoir Current Pool Elevation 653.5 NGVD29 Data current as of 12 JUNE 2017
Hartwell Basin Rainfall Thurmond Basin Rainfall Deficit since 1/1/2006 1/1/2007 1/1/2008 1/1/2009 Hartwell 20.5 29.4 17.1 2.8 Thurmond 9.9 15.2 6.5 -0.4
El Nino La Nina Mid-May 2017 ENSO Forecast More Rainfall La Nina More Tropical Systems On June 8 NOAA Climate Prediction Center stated that the chance of El Niño is at 35-50% during the Northern Hemisphere fall and winter.
Pool Projection
DROUGHT TRIGGER LEVELS 2012 Drought Plan Level 1 (Reduce Thurmond Outflow to 4200 CFS Level 2 (Reduce Thurmond Outflow to 4000 CFS), (3600 Nov1-Jan31) Level 3 (Reduce Thurmond Outflow to 3800 CFS), (3100 Nov1-Jan31) Level 4 (Reduce Thurmond Outflow to 3600 CFS), (3100 Nov1-Jan31) Level 4 (Reduce Thurmond Outflow to 3600 CFS), (3100 Nov1-Jan31) Flood Operation Normal Operation Drought Operation File Name
And now for some insight to the seasonal forecast… File Name
Water Management 101
Hartwell PROJECT 3rd most-visited Corps project – 9.3 M Visitors/yr Constructed in 1962 56,000 acre water surface (660 ft-msl) 962-mile shoreline 5 Turbines with a 422 MW Generating capacity Largest shoreline management program in the Corps with 47,523 permitted activities Built in the late 50’s and early 60’s, Hartwell Lake is only slightly smaller than its older sister, J. Strom Thurmond Lake, above Augusta, Georgia. The dam lies seven miles below the confluence of the Seneca and Tugaloo Rivers which join to form the Savannah. At full summer pool, the lake has a shoreline of almost 1000 miles. The five turbines are housed in the Corps’ only outdoor power plant. At the completion of the current rehabilitation project, the project will be able to provide 422 megawatts of electricity. Hartwell Lake has the Corps’ largest shoreline permitting program in the Corps of Engineers. Fifty percent of the public shoreline is allocated for limited private use. Over 10,000 boat docks ring the lake and there are a total of 30,000 permitted activities.
Richard B. Russell Project Largest Corps power plant east of Mississippi River Completed in 1984 26,653 acre water surface (475 ft-msl) 540-mile shoreline Four conventional turbines 328 MW Generating Capacity Four pump turbines 320 MW Generating Capacity 27 recreation sites 4 state parks
J. Strom Thurmond Project 8th most-visited Corps project - 5.0M Visitors/yr Completed in 1952 71,100 acre water surface (330 ft-msl) Seven turbines capable of generating 364 MW 1,200 miles of shoreline 76 recreation sites
Congressional Authorization Congressional Authorization Authorized Purpose Hartwell Russell Thurmond Flood Damage Reduction Flood Control Act of 1950 Flood Control Act of 1966 Flood Control Act of 1944 Hydropower Navigation N/A Water Supply Water Supply Act of 1958 Water Quality Federal Water Pollution Control Act of 1972 Fish and Wildlife Federal Water Project Recreation Act of 1965 Federal Water Project Recreation Act of 1965, WRDA 1986 WRDA 1986 Recreation Federal Water Project Recreation Act of 1965
Pool Schematic The Hartwell Project is the most upstream Reservoir in the Corps 3 project system. The Hartwell conservation pool holds over 1.4 million acre-ft and extends 35 feet from 660 ft-msl to 625 msl.
What is… Induced Surcharge Storage (665 - 674) (Dec 2015) Additional flood storage gained when gates are lifted allowing pool > 665 Flood Storage (660 - 665) used to temporarily store inflows from flood events Conservation Storage (625 - 660) Water Supply Recreation Hydropower Navigation Water Quality Fish and Wildlife Inactive Storage (625 - streambed) Intended for the storage of sediment
Managed as System of Projects We can look at the Savannah River Basin to see a complex system supporting the needs of many different requirements. You are familiar with the three major dams pictured here. Further upriver, Duke Energy operates hydropower dams and GA Power operates run-of-the-river dams. Down river from our dams is Steven's Creek Dam, City of Augusta diversion dam, which diverts into the Augusta Canal, Augusta Levee, and Augusta's New Savannah Bluff Lock and Dam. Every part of the basin affects the other parts, and we must be aware of what is happening in every area to make informed operating decisions. Total Drainage Basin Area -10,580 sq miles 31 31
Collaborating Agencies
Drainage Basins Hartwell = 1294 Square Miles (Local Basin) 1 in. Runoff = 34,799 cfs-days = 1.2 ft. @ 660.0 Russell = 802 Square Miles (Local Basin) 1 in. Runoff = 21,566 cfs-days = 1.5 ft. @ 475.0 Thurmond = 2890 Square Miles (Local Basin) 1 in. Runoff = 87,502 cfs-days = 2.2 ft. @ 330.0
Water Management Objectives Minimize Flood Damages and Loss of Life Provide Maximum Benefit to the Public Water Supply Water Quality Recreation Navigation Hydro-Production Fish and Wildlife Management Flood Risk Management Balance Drought impacts to Project Purposes Follow USACE Environmental Operating Principles Adaptively Manage within Corps Authorities Educate the Public File Name
Balancing Project Purposes Flood Management Level 1 Operation Level 2 Operation Level 3 Operation Normal Operation Level 4 Operation Flood Management Flood Risk Management Guide Curve Navigation Non-Drought Hydropower Mild Drought Drought Level 1 Recreation Drought Level 2 Moderate Drought Fish and Wildlife Drought Level 3 Severe Drought Water Quality Drought Level 4 Catastrophic Drought Water Supply
POOL BALANCING Hartwell vs Thurmond
Precipitation Estimates (Doppler Radar) Data used to make our decisions
USGS Stream Gage Network GOES Satellite RIVER FORECAST CENTER INFLOW FORECAST STREAMFLOW FORECAST
Sources of Inflow Water Withdrawals Loss to Vegetation Inflow from Rainfall Releases from upstream Projects Water Withdrawals Insignificant Loss to Vegetation Seasonally varying Loss to Groundwater Insignificant, slow to recover Releases Limited by current conditions Evaporation… File Name
Average Lake Evaporation Seasonal Evaporation can account for about 25% of the total water leaving the reservoir.
Typical Release Range Flood Operations (30,000 cfs Channel Capacity) Normal Operations (3800 cfs – 30,000 cfs) In-Lake Fish Spawn (keep pools stable in spring) Meet Ecological Flow Needs Meet Hydropower Commitments Drought Management (3100 cfs - 4200 cfs)
Flood Management Flood Damages Prevented (Cumulative) Channel Capacity = 30,000 cfs (Augusta) Release not to exceed Channel Capacity Seasonally Varying Flood Storage Hartwell and Thurmond Operate as a system Minimize downstream flooding/damages Protect the integrity of the Dams Induce additional Flood Surcharge Storage if necessary Flood Damages Prevented (Cumulative) Hartwell $68,887,000 Russell $23,545,000 Thurmond $114,639,000
Drought MANAGEMENT History Objectives First Drought Contingency Plan (March 1989) 0, 4500, 3600 Update 2006 (Adjusted Trigger Flows) 4200, 4000, 3800 Update 2010 (Level 3 adjustment to 3600, Wintertime reduction to 3100) Update 2011 (Clarify Level 4 Operations) Update 2012 (Introduced Broad River Gage, Winter reductions Levels 2 & 3) Update 2014 (New Storage Balance Agreement/Duke Energy) Update 2017 (Currently out for Public Comment) Objectives Balance impacts to authorized purposes Balance impacts between upstream and downstream Elevation Based Triggers, limit releases based on drought severity Maintain an updated Plan
Pool Balancing Procedure Hartwell Russell Thurmond 665 480 335 660 475 330 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Level 1 Level 1 470 Level 2 Level 2 Level 3 Level 3 Level 4 312 Once the pools have declined more than 15 feet we balance Hartwell and Thurmond based on the percent of Conservation pool depth remaining 7:1 Then we balance the Hartwell and Thurmond pools foot for foot while in the top 15 feet of their respective Conservation pools 1:1 The lakes were designed to meet specific authorized project purposes. There is a limit as to how far each lake elevation can fluctuate. Lake Hartwell’s pool is designed to operate between full pool and 625 ft. mean sea level. Full pool varies seasonally between 660 ft. mean sea level during the summer months, and 656 ft. mean sea level in the winter months. This normal range of fluctuation is called the conservation pool. The size of the conservation pool is designed so that during dry periods a specific rate of release can be maintained to meet downstream flow requirements for water quality, water supply and hydropower. If we were to further limit the amount that the pool could be drawn upon, then we could not meet these needs. It is very important to note, that contrary to popular misunderstanding and rumors, we have been releasing only enough water to meet state mandated water quality and related supply needs since May of 1999. The average release at Lake Thurmond since that time was 4283 cubic feet per second. The average since September 12, 2002, the date we hit trigger level 3, was 3470 cubic feet per second. During Flood Control Operations we evacuate the downstream flood storage first Level 4 625
Storage Balancing Procedure (USACE and DUKE) USACE Projects Duke Projects The Duke Projects have limited flood control storage. The USACE projects utilize their Flood Control Storage to lessen the effects of flooding on Augusta. 800 660 Level 1 - 82% USACE requires no release from KEOWEE until the USACE projects reach 90% conservation storage remaining. Level 2 – 73% Percent of Conservation Storage Remaining Once the USACE Projects reach 80% conservation storage remaining, the Duke Projects will release to match the remaining conservation storage. Level 3 – 43% Keowee 800-790 Jocassee 1080-1110 Bad Creek 2310 – 2150 Hartwell Guide Curve – 625 Russell Guide Curve (475) – 470 Thurmond Guide Curve - 312 No required release from Duke Projects if Dukes % conservation storage is less than 12% 625 Bad Creek Jocassee Keowee Hartwell Russell Thurmond
Where To From Here? Is the Drought over??? Not Yet… Continue with release restrictions per Drought Plan
Questions?
WATER MANAGEMENT WEB PAGE http://water.sas.usace.army.mil
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A Notice of Availability of a Draft Environmental Assessment Savannah River Basin Comprehensive Study Interim #2 Released to the Public on June 12, 2017 Public Workshop 12 July 17 @ 2:00 to 4:00 PM North Augusta Municipal Building, Palmetto Terrace 100 Georgia Ave, North Augusta, SC 29841 Savannah District, U.S. Army Corps of Engineers, Planning Branch Comments will be taken until: ATTN: Mr. Nathan Dayan (PB) 12 O'CLOCK NOON, July 13, 2017 100 West Oglethorpe Avenue Savannah, Georgia 31401-3640, by FAX: 912-652-5787 or by emailing: CESAS-PD@usace.army.mil. The reports can be found at: http://www.sas.usace.army.mil/About/Divisions-and-Offices/Planning-Division/Plans-and-Reports/