Transcript Slide 1

IMPROVING MILLERTON LAKE
FLOOD CONTROL OPERATIONS
TO INCREASE WATER SUPPLY
Mr. Antonio M. Buelna, P.E.
Mr. Douglas DeFlitch
Ms. Katie Lee
October 29, 2009
Reclamation Mission Statement
Is to manage, develop, and protect water and related
resources in an environmentally and economically
sound manner in the interest of the American public.
Overview
• Reclamation and Friant History
• Watershed and Supplies
• Millerton Lake Operations
– Normal Operations
– Flood Operations
• 2006 Operations at Millerton Lake
• Upper San Joaquin Basin Model
• Climate Change in the Upper Basin
• Summary
Bureau of Reclamation History
• June 17, 1902, President
Theodore Roosevelt signed the
Reclamation Act:
– Settlement in the West by providing
water for small-scale family farms.
• August 26, 1937, President
Franklin Delano Roosevelt
signed the River and Harbor Act:
– Authorized the Central Valley Project
for construction including Friant
Dam and other public works
facilities.
Friant Dam History
• Completed in 1942
– Height: 319 feet
– Crest Length: 3,488 feet
• Used for Flood Control & Water
Conservation to meet demands.
– Irrigation
– Municipal
– Industrial
• Downstream release points:
– San Joaquin River
– Friant-Kern Canal
– Madera Canal
Watershed and Supplies
Table 1: Average Annual Historical Runoff
Dam
Stream
1956-2005 [50-year average]
1927-1934 [7-year average]
Shasta
Sacramento
6,107,000 AF
3,650,000 AF
Friant
San Joaquin
1,836,000 AF
1,040,000 AF
Folsom
American
2,719,000 AF
1,560,000 AF
Trinity
Trinity
1,398,000 AF
680,000 AF
------ Redding
to Bakersfield: 447 miles
----- Sacramento to Fresno: 176 miles
Facts:
– The Central Valley: 1/3 is Valley Floor,
2/3 are Mountainous
– Cascade Range Elevation (North):
14,000 ft
– Sierra Nevada Elevation (East):
14,000 ft
– Coast Range Elevation (West):
8,000 ft
Millerton Lake Operations
Stakeholders
Downstream Interest:
Private Utilities:
• Lower San Joaquin River Levee District
• Southern California Edison (SCE)
• Land Owners
• Pacific Gas and Electric (PG&E)
United States Federal and State
Agencies:
Water Users:
• Army Corps of Engineers
• Department of Water Resources (DWR)
• National Weather Service
• 28 Districts
– Irrigation, Municipal, Industrial
Millerton Lake Operations
Flood Operations – Millerton Lake
•
Upper San Joaquin River Floods occurs about
4 out of 10 years.
•
Rain Floods: results of intense rainfall in the
Sierra Mountains.
•
–
Period typically: November to March
–
January 2, 1997: largest rain flood estimated
maximum daily flow of 77,500 cfs and a 7-day
volume of 416,700 AF.
Snowmelt Floods: results of mountain snowmelt.
–
–
–
Snowmelt floods are sustained, moderate flows for 2 – 3 months,
resulting in large volumes of runoff.
Snowmelt produces ~70% of annual water supply.
1906: largest snowmelt flood with a maximum daily flow of 26,300 cfs
and a April – July volume of 3.34 million AF.
Flood Operations – Millerton Lake
520,500 AF
170,000 AF
Snowmelt
390,000 AF
130,000 AF
Dead Pool Space = 130,000 AF
Flood Control Storage Reservation Diagram
2006 Operations at Millerton Lake
•
March 1, 2006, the San Joaquin River basin hydrologic conditions
were at the historic average and the DWR 50 Percent exceedance
forecast was 1.27 million AF.
•
By early April, storage capacity
was at 95 percent.
•
First week of April produced 10
inches of rain.
–
April’s 100-year average
precipitation is 3 inches.
–
More than 300 percent of
normal conditions.
2006 Operations at Millerton Lake
26,000 CFS
525,747 AF
520,823 AF
522,201 AF
2006 Operations - Forecasting Error
50% Forecast vs. Flood Volume
2006 Operations
Upper San Joaquin Basin Model (USAN)
• The USAN model was developed to
study re-operation of the upstream
reservoirs to enhance the Friant
Division water supply.
– Improve Friant Division operations
and enhance the water supply.
– Simulates Flood real-time data from
1896 to present.
– Used daily to produce short-term
reservoir operations with real-time
data (storage, deliveries, releases,
etc.)
• USAN uses a daily time step of
projected operations applied to
historic unimpaired flow data.
Upper San Joaquin Basin Model (USAN)
• USAN limitations:
– Operational decisions based on forecasts.
– Millerton Lake February 1st storage plus the February – July
unregulated flow forecast to determine the amount of water
available for deliveries each year.
– Difficult with flexibility to varying conditions or water years in
the volume of water available for diversion during snowmelts of
equal volume.
• (Distribution of snowmelt may cause variations in over 100,000 AF)
Climate Change in the Upper Basin
• Important effects to Friant
Operations:
– Changes in rainfall timing and
intensity
– Total snow and ice coverage
– A rise in ambient temperature
• Total snow accumulation in the
western U.S. has declined over the
period 1925-2000.
– Higher temperatures threaten to reduce accumulation up to 40%
in the Sierra Nevada.
• Climate change effects the watershed and operations at
Friant Dam, increasing the probability of a rain flood and
decreasing the magnitude of snowmelt flows.
Precipitation Trends
50
Huntington Lake Precipitation
1920 - 2000
48
48.8
2001-2010
Prediction:
48.91 inches
46
Average
increase of
+1.55 inches
per ten years
Precipitation (inches)
44
y = 1.5738x + 34.743
2
R = 0.8742
42
43.9
43.8
42.4
41.5
40
40.2
39.5
2001-2008
2001-2009
38.68 in
38
36
34
34.5
32
30
1921-1930
1931-1940
1941-1950
1951-1960
1961-1970
Water Years
1971-1980
1981-1990
1991-2000
2001-2010
Summary
• The San Joaquin River has two major
runoff seasons
– November through March is
predominately rain
– April through July is predominately
snowmelt
• Snowmelt produces ~70% of annual
water supply
• Managing Friant Division’s Central Valley Project Water Supply
considers:
– The information needed to make operational decisions
– The speculative nature of some information (especially early in the
season)
– The importance of water supply to the end user
– The importance of providing protection from floods
• A mission that requires close communication and coordination with
many parties and a significant amount of professional judgment.
Typical Day at Millerton Lake
???
Questions?
Thank You
PowerPoint By:
Robert Campbell, Rufino Gonzalez