reclamation...draft reservoir to near elevation 3617-3621 by march 31 – preference to river flow...
TRANSCRIPT
Yellowtail Dam & Bighorn Lake Operating Criteria Review
Billings, MTSeptember 29, 2009
RECLAMATIONManaging Water in the West
WIND RIVER RANGE
OPERATING CRITERIA REVIEW GOALS
• Improve Overall Project Benefits
– Higher Lake Levels for Recreation and Fishery
– More Consistently Meet Desired Fishery Flow Targets
– Enhance Power Generation
– Improve Flood Control Operations
– More Transparent Methods for Operating Decisions
PROPOSED CHANGES
• Modified Reservoir Elevation Targets
• Revised Method for Calculating River Gains
• Improved Method for Forecasting Winter Gains
• Improved &Transparent Procedure for Setting Winter Release
• New Operating Procedure for Spring Runoff Season using Reservoir Operational Rule Curves
PROPOSED RESERVOIR TARGETS
Date Existing Proposed Difference _______ Targets Targets (feet)
Oct 31 3635 3638-40 +3-5 ft
Nov 30 3630 Eliminated
Mar 31 3605-14 3617-21 +7-13 ft
July 31 3640 3640 Same
November-March Gains
• Gains Prior to 1991 not used in Analysis
• New Method for Calculating Gains
• Nov-Mar Gain Forecast based on Correlation with Actual April-Oct Gains
Trend in Nov-Mar Gains 1968-2000Bighorn Lake Nov-Mar Gains
1968-2000
0
100000
200000
300000
400000
500000
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
Gai
ns a
cre-
feet
Nov-Mar Release Calculation
• Water Balance Equation Used to Calculate Nov-Mar Release Rate Based On:
– Nov-Mar Release from Buffalo Bill and Boysen Reservoirs– Forecasted Nov-Mar River Gains– Draft Reservoir to near Elevation 3617-3621 by March 31– Preference to River Flow before reducing releases below
2000 cfs– Preference to Lake Level before increasing releases above
2500 cfs– Minimize reductions in River Release.
March 31 Reservoir Level Targets
River Release March 31 Target Elev.
Greater Than 2500 cfs 3620.6
2000-2500 cfs 3618.0
Less Than 2000 cfs 3616.7
Operational Rule Curves April-July
April-July Inflow HydrographsBighorn Lake April-July Inflow
02000400060008000
10000120001400016000
4/1
4/8
4/15
4/22
4/29 5/
6
5/13
5/20
5/27 6/
3
6/10
6/17
6/24 7/
1
7/8
7/15
7/22
7/29
Inflo
w C
FS
LD LQ Medium UQ UD Max
Bighorn Lake April-July Rule CurvesBighorn Lake Rule Curves
3600.0
3610.0
3620.0
3630.0
3640.0
3/31 4/
74/
144/
214/
28 5/5
5/12
5/19
5/26 6/
26/
96/
166/
236/
30 7/7
7/14
7/21
7/28
Lake
Ele
v. fe
et
Min Fill 28% Medium UQ UD Max
Bighorn Lake River ReleaseBighorn River Release
0
2000
4000
6000
8000
10000
120003/
31 4/7
4/14
4/21
4/28 5/
5
5/12
5/19
5/26 6/
2
6/9
6/16
6/23
6/30 7/
7
7/14
7/21
7/28
Riv
er F
low
CFS
Min Fill Medium UQ UD Max
RESULTSBased on 1988-2008 Model Study
Results Reservoir ElevationBighorn Lake Elev. Modified Criteria vs. Historic
1988-2008 Averages
360036053610361536203625363036353640
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
Lake
Lev
el fe
et
Modified Criteria Historic
Results River FlowsBighorn River below Afterbay Dam Modifed Criteria vs Historic
1988-2008 Averages
15002000250030003500400045005000
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
Dis
char
ge c
fs
Modified Criteria Historic
Percent of Time Fishery Flows are MetBighorn River Fishery Flows 1988-2008
% of of Time above Fishery Flow Targets
0
20
40
60
80
100
1300 1500 2000 2500 3500
Perc
ent o
f Tim
e
Historic Modif ied Criteria
Power Generation
Yellowtail Dam Power Generation Modified Criteria vs. Historic 1988-2008
40.050.060.070.080.090.0
100.0
Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
Gen
erat
ion
GW
H
Modified Criteria Historic
Power Generation GWHs
Period Mod Criteria Historic Difference
Annual 780.1 762.2 +17.9
Dec-Feb 153.8 156.0 - 2.2
July-Aug 165.7 167.5 - 1.8
1988-2008 Compared to 1967-2008
Period Average Annual Inflow AF
1988-2008 1,992,619
1967-2008 2,343,002
1988-2008 (w/o 01-07) 2,327,807
Results Reservoir Elevation w/o 01-07
Bighorn Lake Elev. Modified Criteria vs. Historic1988-2008 (w/o 01-07) Averages
360036053610361536203625363036353640
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
Lake
Lev
el fe
et
Modif ied Criteria Historic
Results River Flows w/o 01-07Bighorn River below Afterbay Dam Modifed Criteria vs Historic
1988-2008 Averages (w/o 01-07)
15002000250030003500400045005000
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
Disc
harg
e cf
s
Modified Criteria Historic
Results – Summary 1988-2008 Study Period
• Lake Levels– Jan-April 7-8 feet higher– May-June 3 feet higher– July-Dec 4-5 feet higher
• River Flows– 1,500 cfs + 8% of time, met 100% of time for study period– 2,000 cfs + 5% of time– 2,500 cfs + 5% of time– 3,500 cfs - 3% of time
• Power Generation +2% increase • Flood Control – Slight Improvement
Comparisons for 2009
2009 Bighorn Lake Nov-Mar River Release
River End of March Release Lake Elevation
Revised Criteria 2546 cfs 3623 ft
Actual 2450 cfs 3627 ft
Difference +96 cfs - 4 ft
Bighorn Lake Proposed Criteria vs. Actual 2009
Bighorn Lake Elevation 2009Modified Criteria vs. Acutal
3620
3625
3630
3635
3640
Oct Nov Dec Jan Feb MarEnd of Month
Elev
atio
n fe
et
Modified Criteria Actual
Bighorn River Proposed Criteria vs Actual 2009
Bighorn River Flow 2009Modified Criteria vs. Actual
22002300
24002500
26002700
2800
Oct Nov Dec Jan Feb MarEnd of Month
Disc
harg
e cf
s
Modified Criteria Actual
Bighorn Lake Elevation April- July 2009
Bighorn Lake Rule Curve vs Actual Operation 2009
3610.03615.03620.03625.03630.03635.03640.03645.03650.0
4/1 4/8 4/15
4/22
4/29 5/6 5/13
5/20
5/27 6/3 6/10
6/17
6/24 7/1 7/8 7/15
7/22
7/29
Elev
atio
n fe
et
Rule Curve Reoperation Actual Top of Joint Use
Bighorn River April-July 2009Bighorn Lake Rule Curve Operation vs Actual 2009
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
4/1 4/8 4/15
4/22
4/29 5/6 5/13
5/20
5/27 6/3 6/10
6/17
6/24 7/1 7/8 7/15
7/22
7/29
Dis
char
ge C
FS
Rule Curve Reoperation Actual
Bighorn Lake Forecasted Apr-July InflowBighorn Lake In flow April-Ju ly 2009
02000400060008000
1000012000140001600018000
4/1 4/8 4/15
4/22
4/29 5/6 5/13
5/20
5/27 6/3 6/10
6/17
6/24 7/1 7/8 7/15
7/22
7/29
Inflo
w c
fs
Forecast
Bighorn Lake April-July Inflow Forecasted vs Actual
Bighorn Lake Inflow April-July 2009
02,0004,0006,0008,000
10,00012,00014,00016,00018,000
4/1 4/8 4/15
4/22
4/29 5/6 5/13
5/20
5/27 6/3 6/10
6/17
6/24 7/1 7/8 7/15
7/22
7/29
Inflo
w c
fs
Actual Forecast
NRCS Apr-July Forecast
Rule Curve Inflow vs Actual 2009
Bighorn Lake Inflow April-July 2009
02,0004,0006,0008,000
10,00012,00014,00016,00018,000
4/1 4/8 4/15
4/22
4/29 5/6 5/13
5/20
5/27 6/3 6/10
6/17
6/24 7/1 7/8 7/15
7/22
7/29
Inflo
w c
fs
Actual Forecast
2009 Rule Curve using Actual Inflow
Bighorn Lake Elevation for Forecast A-J Inflow with Rule Curves
3600
3610
3620
3630
3640
3/314/14
4/285/12
5/26 6/9 6/23 7/7 7/21
Elev
atio
n in
feet
Min Fill Max Forecast
LOOKING AHEAD TO 2010
River Release Nov-Mar 2010
• Planned Boysen Release - 900 cfs
• Planned Buffalo Bill Release – 390 cfs
• Forecasted Nov-Mar Gains - 244,000 acre-feet
• End of Oct. Lake Level – 3638-3639 ft
• Calculated River Release Rate - 2700-2800 cfs
• Expected End of March Lake Elev. - 3620.6 ft
Discussion & Questions
Bighorn Lake Rule Curve vs Actual Operation 2009
3610.03615.03620.03625.03630.03635.03640.03645.03650.0
4/1 4/84/1
54/224/29 5/65/135/20 5/2
7 6/3 6/10
6/17
6/24 7/1 7/87/157/22 7/2
9El
evat
ion
feet
Rule Curve Reoperation Actual Top of Joint Use
Bighorn Lake Rule Curve Operation2009
3610.0
3615.0
3620.0
3625.0
3630.0
3635.0
3640.0
3645.0
3650.0
4/1 4/8 4/15
4/22
4/29 5/6 5/13
5/20
5/27 6/3 6/10
6/17
6/24 7/1 7/8 7/15
7/22
7/29
Elev
atio
n fe
et
Rule Curve Elevation ft Top of Joint Use
Bighorn Lake Rule Curve vs Actual Operation 2009
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
4/1 4/8 4/15
4/22
4/29 5/6 5/13
5/20
5/27 6/3 6/10
6/17
6/24 7/1 7/8 7/15
7/22
7/29
Dis
char
ge C
FS
Rule Curve Reoperation Actual