Skagit River Hydrology Skagit River Hydrology Performed by Bill - - PowerPoint PPT Presentation

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Skagit River Hydrology Skagit River Hydrology Performed by Bill - - PowerPoint PPT Presentation

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Skagit River Hydrology Skagit River Hydrology Performed by Bill Cronin and Loren Jangaard Jangaard, USACE , USACE Performed by Bill Cronin and Loren Technically Reviewed by Ken Brettmann Brettmann, USACE , USACE Technically Reviewed by Ken

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SLIDE 1

Skagit River Hydrology Skagit River Hydrology

Performed by Bill Cronin and Loren Performed by Bill Cronin and Loren Jangaard Jangaard, USACE , USACE Technically Reviewed by Ken Technically Reviewed by Ken Brettmann Brettmann, USACE , USACE Presented and Presented and Backchecked Backchecked by Ted Perkins by Ted Perkins

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SLIDE 2

Skagit River Hydrology Skagit River Hydrology

  • Definition and

Definition and Objective Objective

  • Weather Patterns

Weather Patterns

  • Streamflow

Streamflow Analysis Analysis

  • Limits of Flood

Limits of Flood Control Control

  • Questions

Questions

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SLIDE 3

Skagit River Hydrology Skagit River Hydrology Definition and Objective Definition and Objective

Cards Cards Chance of Chance of Occurrence Occurrence Recurrence Recurrence Flood Event Flood Event 3 Clubs 3 Clubs 1 in 52 1 in 52 1.9% 1.9% 52 52-

  • year

year 3 or 4 Clubs 3 or 4 Clubs 1 in 26 1 in 26 3.8% 3.8% 26 26-

  • year

Flood Event Flood Event Recurrence Recurrence Chance of Chance of Occurrence Occurrence 10 10-

  • year

year 10% 10% 1 in 10 1 in 10 100 100-

  • year

year 1% 1% 1 in 100 1 in 100 500 500-

  • year

year 0.2% 0.2% 1 in 500 1 in 500 year How many cards are in the Hydrology deck?

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SLIDE 4

Weather Patterns Weather Patterns

  • There are a lot of cards in the deck so need a long period of

record

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SLIDE 5

Hydrologic Record Hydrologic Record

  • Long Period of

Long Period of Record Record

  • Consistent human

Consistent human influence record influence record

  • Consistent natural

Consistent natural influence record influence record

  • Location

Location

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SLIDE 6

Frequency Analyses Frequency Analyses

  • Rank Flood

Rank Flood Events Events

  • Plot Data

Plot Data

  • Peak, 1

Peak, 1-

  • day,

day, 3 3-

  • day, 7

day, 7-

  • day

day

0.1 0.5 1.0 2.0 5.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 95.0 98.0 99.0

EXCEEDANCE FREQUENCY IN PERCENT

2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 10,000 100,000 1,000,000

DISCHARGE (cfs)

0.2 LOG TRANSFORM SYSTEMATIC STATISTICS NUMBER OF EVENTS MEAN=
  • ST. DEV.=
COMPUTED SKEW= REGIONAL SKEW= ADOPTED SKEW= 4.9744 0.1744 0.6973 0.0000 0.5000 HISTORIC EVENTS= HIGH OUTLIERS= LOW OUTLIERS= ZERO OR MISSING= SYSTEMATIC EVENTS= HISTORIC RECORD= 4 52 99 YRS

SKAGIT RIVER NEAR CONCRETE USGS #12194000 UNREGULATED PEAK FLOWS DERIVED FROM PEAK VERSUS 1DAY REGRESSION CORPS OF ENGINEERS, SEATTLE DISTRICT 28 APR 1998 BASIN AREA= 2737 SQ MI WATER YEARS OF RECORD HISTORIC EVENTS= 1898, 1909, 1917, 1921 RECORDED EVENTS= 1925, 1944-1991, 1994-1996

CONSTRUCTED BY:
  • C. FITZGERALD, E.I.T.
APPROVED BY: ____________________________________ HEC-FFA COMPUTED CURVE EXPECTED PROBABILITY ADJUSTMENT 5% CONFIDENCE LIMITS 95% CONFIDENCE LIMITS MEDIAN PLOTTING POSITIONS

F l

  • w

Frequency

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SLIDE 7

Gage Assessment Gage Assessment

Data Type Data Type Mount Vernon Mount Vernon Sedro Sedro-

  • Woolley

Woolley Concrete Concrete Peak Peak 1940 1940-

  • present

present 1896 1896-

  • 7, 1906,

7, 1906, 1908 1908-

  • 22, 1975

22, 1975-

  • 9

9 1897, 1909, 1897, 1909, 1917, 1921, 1917, 1921, 1924 1924-

  • present

present Daily Daily 1940 1940-

  • present

present 1908 1908-

  • 23, 1975

23, 1975-

  • 80

80 1924 1924-

  • present

present Years Years 58 58 22, 16 22, 16 78, 74 78, 74 Problems Problems Changed Changed Watershed, Dam Watershed, Dam Influence, Influence, Attenuation Attenuation Slightly Changed Slightly Changed Watershed, Dam Watershed, Dam Influence, Influence, Attenuation Attenuation Dam Influence Dam Influence

  • Concrete Gage Has the Longest Consistent Record
  • All Gages are Used to Verify Results
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SLIDE 8

The Impact of Volume on Peaks The Impact of Volume on Peaks

02 03 04 05 06 07 08 Dec75 20000 40000 60000 80000 100000 120000 140000

CONW,MTVER

Time FLOW (CFS) Legend SKAGIT MTVER SKAGIT CONW Missing Data

Skagit River at Concrete Skagit River at Mount Vernon

Time F l

  • w

December 1975 Event

  • The Volume of Water at Concrete is Accounted for Downstream
  • Longer Duration Flood Creates Higher Peak Downstream
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SLIDE 9

The Impact of Volume on Peaks The Impact of Volume on Peaks

28 29 30 01 02 03 04 Nov95 Dec95 40000 60000 80000 100000 120000 140000 160000

CONW,MVEW

Time FLOW REG (CFS) FLOW (CFS) Legend SKAGIT MVEW SKAGIT CONW SKAGIT MVEW SKAGIT CONW Missing Data

Skagit River at Concrete Skagit River at Mount Vernon

  • The Volume of Water at Concrete is Accounted for Downstream
  • Shorter Duration Flood Results in Lower Peak Downstream

Time F l

  • w

November 1995 Event

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SLIDE 10

Influence of Dams Influence of Dams

Year Year Dam Dam Note Note 1924 1924 Low Low Gorge Gorge First Built First Built 1954 1954 Ross Ross Flood Flood Storage Storage 1956 1956 Upper Upper Baker Baker Flood Flood Storage Storage 1977 1977 Upper Upper Baker Baker Added Flood Added Flood Storage Storage

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SLIDE 11

With Dams Frequency Curve With Dams Frequency Curve

  • Concrete Dam

Concrete Dam Influenced Data Influenced Data (1956 (1956-

  • 97)

97)

  • Control flow when

Control flow when expected to exceed expected to exceed 90,000 90,000 cfs cfs at Concrete at Concrete

  • From 1956

From 1956-

  • 77, only 2

77, only 2 events are regulated events are regulated (11/20/62 (11/20/62-

  • 114,000

114,000 cfs cfs, , 12/4/75 12/4/75 – – 122,000 122,000 cfs cfs)

0.2 LOG TRANSFORM SYSTEMATIC STATISTICS NUMBER OF EVENTS MEAN=
  • ST. DEV.=
COMPUTED SKEW= REGIONAL SKEW= ADOPTED SKEW= HISTORIC EVENTS= HIGH OUTLIERS= LOW OUTLIERS= ZERO OR MISSING= SYSTEMATIC EVENTS=

SKAGIT RIVER NEAR CONCRETE USGS #12194000 REGULATED PEAK FLOW FREQUENCY CURVE CORPS OF ENGINEERS, SEATTLE DISTRICT 28 APR 1998 BASIN AREA= 2737 SQ MI OBSERVED WATER YEARS OF RECORD 1956-1997

CONSTRUCTED BY: WE CRONIN, P.E. APPROVED BY: ____________________________________ 99.0 98.0 95.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 5.0 2.0 1.0

EXCEEDANCE FREQUENCY IN PERCENT

10,000 100,000 1,000,000 20000.00 30000.00 40000.00 50000.00 60000.00 70000.00 80000.00 90000.00 200000.00 300000.00 400000.00 500000.00 600000.00 700000.00 800000.00 900000.00

DISCHARGE (cfs)

REGULATED OBSERVED MEDIAN PLOTTING POSITIONS POLYNOMIAL BEST FIT LINE OBSERVED DATA

)

40 year Record of Dam Controlled Peak Flows

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SLIDE 12

Determine Relationship between Pre Determine Relationship between Pre-

  • Dam and Post

Dam and Post-

  • Dam Flows

Dam Flows

  • Determine Dam

Determine Dam Inflows Inflows

  • Determine Local

Determine Local Flows Between Flows Between Dams and Concrete Dams and Concrete

  • Route to get Without

Route to get Without Dam Flow at Dam Flow at Concrete Concrete

  • Perform Frequency

Perform Frequency Analysis Analysis A Longer Period of Record is Developed for the Without Dam Condition

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SLIDE 13

Without Dam Flows at Concrete Without Dam Flows at Concrete

0.1 0.5 1.0 2.0 5.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 95.0 98.0 99.0

EXCEEDANCE FREQUENCY IN PERCENT

2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 10,000 100,000 1,000,000

DISCHARGE (cfs)

0.2 LOG TRANSFORM SYSTEMATIC STATISTICS NUMBER OF EVENTS MEAN=
  • ST. DEV.=
COMPUTED SKEW= REGIONAL SKEW= ADOPTED SKEW= 4.9744 0.1744 0.6973 0.0000 0.5000 HISTORIC EVENTS= HIGH OUTLIERS= LOW OUTLIERS= ZERO OR MISSING= SYSTEMATIC EVENTS= HISTORIC RECORD= 4 52 99 YRS

SKAGIT RIVER NEAR CONCRETE USGS #12194000 UNREGULATED PEAK FLOWS DERIVED FROM PEAK VERSUS 1DAY REGRESSION CORPS OF ENGINEERS, SEATTLE DISTRICT 28 APR 1998 BASIN AREA= 2737 SQ MI WATER YEARS OF RECORD HISTORIC EVENTS= 1898, 1909, 1917, 1921 RECORDED EVENTS= 1925, 1944-1991, 1994-1996

CONSTRUCTED BY:
  • C. FITZGERALD, E.I.T.
APPROVED BY: ____________________________________ HEC-FFA COMPUTED CURVE EXPECTED PROBABILITY ADJUSTMENT 5% CONFIDENCE LIMITS 95% CONFIDENCE LIMITS MEDIAN PLOTTING POSITIONS
  • Determine Upper Without

Determine Upper Without Dam Frequency Events Dam Frequency Events

  • Correlate to Dam Inflows

Correlate to Dam Inflows

  • Set Up Reservoir Model to

Set Up Reservoir Model to Current Conditions Current Conditions

  • Route these inflows

Route these inflows through dams, add in local through dams, add in local to determine peaks at to determine peaks at Concrete Concrete We can route large hypothetical floods through dams

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SLIDE 14

Development of Regulated Development of Regulated Frequency Curves Frequency Curves

  • Add Routed Peaks to

Add Routed Peaks to Regulated Frequency Curve Regulated Frequency Curve

0.1 0.5 1.0 2.0 5.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 95.0 98.0 99.0

EXCEEDANCE FREQUENCY IN PERCENT

2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 10,000 100,000 1,000,000

DISCHARGE (cfs)

0.2 LOG TRANSFORM SYSTEMATIC STATISTICS NUMBER OF EVENTS MEAN=
  • ST. DEV.=
COMPUTED SKEW= REGIONAL SKEW= ADOPTED SKEW= HISTORIC EVENTS= HIGH OUTLIERS= LOW OUTLIERS= ZERO OR MISSING= SYSTEMATIC EVENTS=

SKAGIT RIVER NEAR CONCRETE USGS #12194000 REGULATED PEAK FLOW FREQUENCY CURVE CORPS OF ENGINEERS, SEATTLE DISTRICT 28 APR 1998 BASIN AREA= 2737 SQ MI OBSERVED WATER YEARS OF RECORD 1956-1997

CONSTRUCTED BY: WE CRONIN, P.E. APPROVED BY: ____________________________________ REGULATED OBSERVED MEDIAN PLOTTING POSITIONS POLYNOMIAL BEST FIT LINE OBSERVED DATA HYDROLOGIC MODEL DERIVED PEAK FLOWS + 2 STD ERROR
  • 2 STD ERROR

1 DAY ROSS RESERVOIR INFLOW VERSUS 1 DAY UNREGULATED FLOW SKAGIT RIVER AT CONCRETE. DATA FOR CONCURRENT DAYS 09/01/1943-09/30/1991, 10/01/1993-09/30/1996

Fit Results Fit 1: Linear, LOG(Y)=B*LOG(X)+A Equation: LOG(Y) = 1.1859 * LOG(X) + -1.47682 Number of data points used = 18658 Average LOG(X) = 4.09286 Average LOG(Y) = 3.37691 Regression sum of squares = 2085.15 Residual sum of squares = 337.261 Coef of determination, R-squared = 0.860774 Residual mean square, sigma-hat-sq'd = 0.0180779

1,000 10,000 100,000 1,000,000

UNREGULATED 1 DAY FLOW CONCRETE (USGS #12149000) (cfs)

100 1,000 10,000 100,000 1 DAY INFLOW TO ROSS RESERVOIR (cfs)

A Longer With Dam Record is Developed

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SLIDE 15

Skagit River at Concrete Peak Flows Skagit River at Concrete Peak Flows

Recurrence Recurrence Instantaneous Instantaneous Peak Peak ( (cfs cfs) ) 1 1-

  • day

day Peak Peak ( (cfs cfs) ) 3 3-

  • day

day Peak Peak ( (cfs cfs) ) 10 10-

  • year

year 124,000 124,000 116,000 116,000 97,000 97,000 25 25-

  • year

year 150,000 150,000 138,000 138,000 107,000 107,000 50 50-

  • year

year 185,000 185,000 170,000 170,000 132,000 132,000 100 100-

  • year

year 222,000 222,000 204,000 204,000 159,000 159,000 500 500-

  • year

year 344,000 344,000 319,000 319,000 250,000 250,000

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SLIDE 16

Hypothetical Hydrographs Hypothetical Hydrographs

TIME (days)

50000 100000 150000 200000 250000 300000

DISCHARGE (cfs)

1 2 3 4 5 6 7 8 9 10 11 12 13 14

100 YEAR HYPOTHETICAL FLOOD AT CONCRETE

UNREGULATED CONDITION (NO RESERVOIRS), PEAK=293,000 cfs CURRENT FLOOD STORAGE CONDITIONS, PEAK=222,000 cfs UNLIMITED FLOOD STORAGE IN RESERVOIRS (NO RESERVOIR DISCHARGES), PEAK=205,000 cfs

Perform Frequency Analyses on Tributary Flows (i.e. Finney, Nookachamps) to add in flow to hydraulic model

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SLIDE 17

Route Flows Using Hydraulic Route Flows Using Hydraulic Model Model

1975 Simulated vs. Observed Hydrograph at Mount Vernon Gage 20000 40000 60000 80000 100000 120000 140000 12/1/1975 0:00 12/2/1975 0:00 12/3/1975 0:00 12/4/1975 0:00 12/5/1975 0:00 12/6/1975 0:00 12/7/1975 0:00 12/8/1975 0:00 Time (hr) Flow (cfs) 1975 Simulated 1975 Observed

Simulated Observed Time F l

  • w

December 1975 Event At Mount Vernon Hydraulic Model is Calibrated to Downstream Gage Data

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SLIDE 18

Limits of Flood Control Limits of Flood Control

SKAGIT BASIN DRAINAGE AREA PIE CHART

DRAINAGE AREA REGULATED BY FLOOD CONTROL DAMS 39% UNREGULATED DRAINAGE AREA 61%

Location Location Drainage Drainage Area Area (mi (mi2

2)

) % of % of Mount Mount Vernon Vernon Mount Mount Vernon Vernon 3,093 3,093 Above Above Upper Upper Baker and Baker and Ross Ross Dams Dams 1,214 1,214 39% 39% Below Below Dams Dams 1,879 1,879 61% 61% 61% of Flow is Uncontrolled

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SLIDE 19

Skagit River Hydrology Skagit River Hydrology

Performed by Bill Cronin and Loren Performed by Bill Cronin and Loren Jangaard Jangaard, USACE , USACE Technically Reviewed by Ken Technically Reviewed by Ken Brettmann Brettmann, USACE , USACE Presented and Presented and Backchecked Backchecked by Ted Perkins by Ted Perkins