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Dry Conditions in the Tennessee Valley. October 30, 2007. Chuck Bach River Operations. Outline. Recap dry conditions Explain how we operated the system in response Describe impacts on system benefits: Navigation Flood-damage reduction Power supply Water quality Water supply Recreation. - PowerPoint PPT Presentation
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Dry Conditions in the Tennessee Valley
October 30, 2007
Chuck BachRiver Operations
Outline
• Recap dry conditions
• Explain how we operated the system in response
• Describe impacts on system benefits:
– Navigation
– Flood-damage reduction
– Power supply
– Water quality
– Water supply
– Recreation
Annual reservoir operating cycle
January 1 Reservoirs are drawn to their lowest level to get ready for flood-producing storms.
June 1 The spring fill, which typically begins inmid-March, is complete, and reservoirs are allowed to fill to their highest level. If water is limited, releases are restricted to the amount of water needed to meet reservoir-specific and system-flow requirements.
Labor Day Drawdown restrictions are lifted. Water is released as needed to meet power demands and provide other benefits.
3-day rainfall ending 10-24-07
Key terms
• Tributary vs. main-stem
• Flood guide
• System minimum operating guide (SMOG)
• Balancing guide
Tennessee River System
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
Vo
lum
e (
10
00
ds
f)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flood guide
Flood guide
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
Vo
lum
e (
10
00
ds
f)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
SMOG
Flood guide
The SMOG is based on the total volume of water in storage in 10 tributary reservoirs: Watauga, South Holston, Cherokee, Douglas, Fontana, Norris, Chatuge, Nottely, Hiwassee, and Blue Ridge.
System Minimum Operating Guide (SMOG)
Chickamauga minimum flow requirements (cfs)
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
Vo
lum
e (
10
00
ds
f)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Balancing Guide 1
SMOG
Flood guide
Balancing guide 1
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
Vo
lum
e (
10
00
ds
f)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Balancing guide 1
SMOG
Flood guide
Balancing guide 3
Balancing guide 2
Balancing guides 2 and 3
Tributary reservoir balancing
-60
-40
-20
0
20
40
60
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Ru
no
ff (
Pe
rce
nt
of
No
rma
l)
2010
1941
2000
2006
1988
1986
1985
2007
Annual runoff variability (Eastern Valley)
FY 2007 rainfall/runoff comparison (Eastern Valley)
Rainfall for FY2007 totaled 33.1 inches, 16.9 inches below normal (66 percent of normal).
Runoff for FY07 totaled 12.5 inches, 10.4 inches below normal (54 percent of normal).
10
20
30
40
50
60
Inc
he
s
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Normal Rainfall
Normal Runoff
Observed Rainfall
Observed Runoff
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
Vo
lum
e (
10
00
ds
f)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Balancing guide 1
2007 storage
SMOG
Flood guide
Balancing guide 3
Balancing guide 2
Total tributary system storage, 2007
Chickamauga minimum flow requirements (cfs)
Observed average weeklyflows at Chickamauga
June 3–September 30, 2007
Week Ending
Cubicfeet persecond
June 3June 10June 17June 24
July 1July 8
July 15July 22July 29
August 5August 12August 19August 26
September 2September 9
September 16September 23September 30
14,23418,53218,61219,06218,39516,16816,70915,00914,93325,01025,00125,00825,29825,02510,987
8,3408,751
10,288
Mid-September elevations, 2001-2007: Nottely
1750
1752
1754
1756
1758
1760
1762
1764
1766
1768
1770
1772
1774
2001 2002 2003 2004 2005 2006 2007
No
tte
ly R
eser
voir
Ele
vati
on
(fe
et)
1757.91758.5
1764.4
1770.9
1771.6
1768.9
1753.2
Mid-September elevations, 2001-2007: Fontana
1677.0
1666.3
1698.0
1688.8
1688.4
1646.7
1680.8
1640
1644
1648
1652
1656
1660
1664
1668
1672
1676
1680
1684
1688
1692
1696
1700
1704
1708
2001 2002 2003 2004 2005 2006 2007
Fo
nta
na
Res
erv
oir
Ele
vati
on
(fe
et)
Mid-September elevations, 2001-2007: Douglas
978.65
969.19
973.84
996.56
974.58
976.87
955.47
940
944
948
952
956
960
964
968
972
976
980
984
988
992
996
1000
2001 2002 2003 2004 2005 2006 2007
Do
ug
las
Res
ervo
ir E
leva
tio
n (
feet
)
Public concerns
• “Why didn’t my reservoir reach full pool this summer?”
• “It rained at my house. Why didn’t the reservoir level go up?”
• “Why is my reservoir lower than the other reservoirs in my area?”
Drought impacts
• Navigation
• Flood-damage reduction
• Power supply
• Water quality
• Water supply
• Recreation
Temperatures Precipitation
NOAA three-month outlook
Reservoir operating strategy
Dry conditions continue:
• Maintain minimum flows; conserve any additional water
• Balance tributary reservoir levels
Rain returns:
• Bring tributary reservoirs up to flood-guide levels
• Balance tributary reservoir levels
Spreading the Message
• Conservation operations since February
• Exceptional drought
• Minimum flow requirements continue
• Hold rain/runoff as available
• Beware the reservoir comparison!
BACK-UP SLIDES
Kentucky minimum flow requirements,October 1–September 30
• 5000 cfs year round (instantaneous)
• 12000 cfs October 1–April 30 (daily)
• 15000 cfs May 1–May 31 (bi-weekly)
• 18000 cfs June 1–August 31 (bi-weekly)
• 15000 cfs September 1–September 30 (bi-weekly)
Note: Bi-weekly is defined as any 14-day rolling period.
Tributary reservoir elevations (feet)
-14.6
-23.8
-18.7
-25.7
-33.1
-52.1
-32.2
-27.3
-7.6
-16.1
0.39
0.39
0.41
0.39
0.37
0.36
0.36
0.35
0.38
0.40
1959.0
1729.0
1771.8
1020.0
1512.6
1701.6
991.5
1069.0
1923.3
1682.0
1944.4Watauga
1705.2South Holston
1753.1Nottely
994.3Norris
1479.5Hiwassee
1649.5Fontana
958.3Douglas
1041.7Cherokee
1915.7Chatuge
1665.9Blue Ridge
ReservoirSeptember 1
ElevationFloodGuide Departure
BalancingRatio
Historical comparison (feet)
193219521944.4Watauga
169517081705.2South Holston
174817621753.1Nottely
9851000994.3Norris
147214851479.5Hiwassee
163016531649.5Fontana
945954958.3Douglas
103210451041.7Cherokee
191419181915.7Chatuge
165516681665.9Blue Ridge
ReservoirSeptember 3
Elevation
CurrentWinter
Target Level
Pre-ROSAverage Winter
Level
Normal runoff
2007 runoff
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Monthly runoff above Chattanooga
200
400
600
800
1000
1200
1400
1600
1800
2000
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Actual
Budgeted
Latest Forecast
GW
HMonthly hydro generation, FY 2007
Mid-September elevations, 2001-2007: Norris
1007.4
997.1
1009.0
1012.9
1009.0
1007.4
992.4990
992
994
996
998
1000
1002
1004
1006
1008
1010
1012
1014
1016
2001 2002 2003 2004 2005 2006 2007
No
rris
Res
ervo
ir E
leva
tio
n (
feet
)
Mid-September elevations, 2001-2007: Cherokee
1055.7
1046.8
1059.5
1064.4
1054.7
1057.5
1042.0
1038
1040
1042
1044
1046
1048
1050
1052
1054
1056
1058
1060
1062
1064
1066
2001 2002 2003 2004 2005 2006 2007
Ch
ero
kee
Re
serv
oir
Ele
vati
on
(fe
et)
Mid-September elevations, 2001-2007: Hiwassee
1505.1
1503.9
1506.7
1511.7
1507.5 1507.1
1479.01476
1480
1484
1488
1492
1496
1500
1504
1508
1512
1516
1520
2001 2002 2003 2004 2005 2006 2007
Hiw
asse
e R
eser
voir
Ele
vati
on
(fe
et)
Mid-September elevations, 2001-2007: Watauga
1945.1
1942.4
1950.2
1960.6
1952.6
1950.5
1944.0
1940
1942
1944
1946
1948
1950
1952
1954
1956
1958
1960
1962
1964
2001 2002 2003 2004 2005 2006 2007
Wat
aug
a R
eser
voir
Ele
vati
on
(fe
et)
Mid-September elevations, 2001-2007: South Holston
1717.7
1708.8
1719.5
1722.7
1716.4
1720.4
1699.5
1694
1698
1702
1706
1710
1714
1718
1722
1726
2001 2002 2003 2004 2005 2006 2007
So
uth
Ho
lsto
n R
eser
voir
Ele
vat
ion
(fe
et)
Mid-September elevations, 2001-2007: Chatuge
1918.1
1916.8
1920.7
1924.5
1921.8
1921.0
1915.1
1910
1912
1914
1916
1918
1920
1922
1924
1926
1928
1930
2001 2002 2003 2004 2005 2006 2007
Ch
atu
ge
Res
erv
oir
Ele
vati
on
(fe
et)
Mid-September elevations, 2001-2007: Blue Ridge
1671.0 1671.2
1653.0
1682.5
1675.91675.2
1664.4
1650
1654
1658
1662
1666
1670
1674
1678
1682
1686
1690
2001 2002 2003 2004 2005 2006 2007
Blu
e R
idg
e R
eser
voir
Ele
vati
on
(fe
et)
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