Skagit Project - Final Report - 05072012

7/31/2019 Skagit Project - Final Report - 05072012

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Impact of Climate Change on extreme flows and sediment transport in the Skagit River Basin

Michael Noon

May 8th

, 2012

CEE 599L

I. Introduction and Background

The Skagit River basin is the largest freshwater input into Puget Sound, representing

approximately 35% of the total annual discharge from Washington State rivers (Czuba, et al.,

2011). The basin, located on the border of Washington State and British Columbia,

encompasses 3,115 square miles of area ranging from lowland marshes around Mt. Vernon, WA

to volcanic glaciers around Mt. Baker and Glacial Peak (Lee & Hamlet, 2011). The major

components of the river basin relevant to this project are shown in Figure 1, which consists

primarily of the Skagit River with major tributaries that include the Baker, Sauk, Suiattle, and

Cascade rivers. Additionally, there are five hydropower dams in the basin, that includes the

three Seattle City Light (SCL)-owned Gorge, Diablo, and Ross dams, and the two Puget Sound

Energy (PSE) -owned Upper and Lower Baker dams (Lee & Hamlet, 2011).

Figure 1: Map of the Skagit River system model (Source: Google Map)

The dams on the Skagit River are primarily managed for hydropower production, flood control,

fish health, and recreation. This project will focus on examining the impacts of different climate

change scenarios on sediment loading, extreme peak and low flows in the Skagit River.

Hamlet et al (2010) simulated the impact of two climate change scenarios on extreme flow

events in the Skagit River basin; a 5.8oF (A1B) and 4.0

oF (B1) increase in global temperature by


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the 2080s with respect to the 20th

century baseline. They expect the severity of the peak and 7-

day average low flows to increase under climate change in comparison to the historical flows

(Hamlet, et al., 2010). Further work has indicated that while these climate change scenarios will

not significantly increase the overall amount of precipitation in basin on an annual basis, it will

shift the distribution of precipitation away from the summer months to the rest of the year,potentially increasing winter flood risks and exacerbating summer low flows resulting from a

projected loss of snow pack (Lee & Hamlet, 2011). The most notable impact of the more severe

low flows is on fish populations, which require minimum levels of streamflow to allow adult fish

to reach upstream spawning locations and prevent dewatering or stranding of eggs (Anderson,

Gibbs, Hart, Inman, McChesney, & Slattery, 2006). These low flow events generally incur an

economic cost, such as the expending of resources to mitigate low streamflows on fish

populations via in-stream obstacle removals, stoppage of water withdrawals, and fish salvage

operations (Anderson, Gibbs, Hart, Inman, McChesney, & Slattery, 2006). Even recreation can

be impacted as shown by the Sauk River, which requires a minimum of 3,500 cfs to support

rafting and kayaking (Lee & Hamlet, 2011).

The effect of climate change on sediment loading is less clear. Due to the significant amount of

glaciated volcanoes in its headwaters, the Skagit River is a significant source of sediment input

to Puget Sound, representing approximately 43% of 6.5 million tons per year derived from

Washington State rivers (Czuba, et al., 2011). Much of this uncertainty is due to the lack of

understanding on current and historical sediment flows in the Skagit River basin. Development

in basin in the form of transportation (highways and railroads), the dredging and channelization

of flow, and the construction of dikes, tide, and flood gates has led to the increased speed of

sediment transport down the river. However, upstream dams tend to collect sediment from the

headwaters, reducing sediment transport downstream (Lee & Hamlet, 2011). While climate

change can increase sediment flow due to the exposure of previously glacier-covered rock face

and more frequent flooding, it can also trap sediment in newly formed glacial lakes or slow

down sediment transport during low flows (Lee & Hamlet, 2011)

II. Experimental Design

This project will study the impacts of Skagit River sediment loading and extreme flow events

under climate change using a model of the system shown in Figure 1 constructed in Stella. A

diagram of the model components and flows are shown in Figure 2. In particular, the model is

designed to satisfy flood control requirements, hydropower production targets, and minimum

stream flows to protect fish spawning. It does this by first calculating the necessary volume of

water needed to be released to meet any local requirements at the dams. Additional

supplementary releases needed to meet other system-wide requirements are then calculated

and added to the preliminary releases.


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Figure 2: Diagram of the system modeled in Stella used for the simulations

Local Requirements: Minimum required releases from the dam Releases required to satisfy flood rule curves for flood control Releases to keep reservoir levels between full pool and bottom storage volumes

System Requirements:

Additional releases to achieve hydropower energy targets Releases to achieve minimum fish in-stream flow targets Reduction in releases to mitigate downstream flooding

The model was then calibrated by adjusting the monthly hydropower energy targets such that

the simulated reservoir elevations would match the observed historical elevations. A linear

regression of these adjustment factors for 1985 to 2006 with respect to that years April to

September flows was performed and the adjustment factors required for future predicted flows

under climate change was extrapolated from the result (see Appendix A).


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This project used the same climate change scenario of a 5.8oF (A1B) increase in global

temperature by the 2080s with respect to the 20th

century baseline as Hamlet et al (2010). The

streamflows associated with this scenario were determined using the Variable Infiltration

Capacity (VIC) hydrologic model (Hamlet, et al., 2010) for the 2040s (2030-2059) and 2080s

(2070-2099) time periods.

The peak flows and 7-day average low flows per water year for each scenario (historic, 2040s,

and 2080s) were simulated and compared via quantile mapping their cumulative distribution

functions (CDF) using a cunnane quantile estimator. The monthly long-term average and

simulated yearly sediment loading at Mt. Vernon, WA was calculated using a linear regression

from Curran et al (2012).

III. Methods

III.1 Flow calculations

The model uses a daily time-step to provide enough fine detail with flow calculations for each

component (dam or city) calculated via Equation 1.

IN2= OUT1 + INC1,2 EVAP2 WITH2 [1]

Where IN2 is the flow into the downstream component, OUT1 is the outflow from upstream

component, INC1,2 are the incremental flows between the two components (e.g. tributaries,

runoff, and precipitation), EVAP2 is the evaporation from the downstream reservoir (if

applicable), and WITH2 are other net withdrawals between the two components (if applicable)

all in cfs-d.

III.2 Flood Control

Only Ross and Upper Baker Dams are utilized for flood control, which is incorporated in the

model via flood rule curves that specify the maximum storage volume of Ross and Upper Baker

dams over the course of the year. For Ross Dam, the max reservoir elevation is reduced from

1602.5 ft starting Oct 1st

until it reaches is maximum flood control storage of 120,000 acre-ft at

an elevation of 1592 ft by Dec 1st

, which is held at that level until March 15th

(USACE, 1995). For

Upper Baker Dam, the max reservoir elevation of 724 ft is lowered starting on Oct 1st

until it

reaches the max flood control storage of 74,000 acre-ft at an elevation of 712 ft by Nov 15th

,

which is held at that level until March 1st

(USACE, 1985). However, the reservoir storage

volumes may exceed the flood rule curve maximum if the river flow at Concrete, WA is in

excess of the flow target of 62,500 cfs, indicating flood conditions.

III.3 Hydropower Production

For hydropower production, the amount of power generated from the preliminary releases is

compared to the monthly energy targets for the Seattle City Light and Puget Sound Energy


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projects, shown in Table 1. If the energy production is below the desired levels, then the

additional releases necessary to achieve the targets are calculated using Equation 2 and added

to the preliminary releases.

Table 1: Hydropower energy targets for the Seattle City Light and Puget Sound Energy projects

Seattle City Light Project Puget Sound Energy Project

Oct 218,947 58,216

Nov 234,645 67,305

Dec 268,473 73,485

Jan 267,325 74,411

Feb 234,892 72,686

Mar 240,746 65,709

Apr 220,951 59,014

May 209,003 54,096

Jun 201,891 52,474

Jul 204,988 51,753

Aug 203,649 52,577

Sep 194,489 53,272

Energy Target (MWh)Month

[2]

Where R is the dam release in cfs, E is the energy target in MWh, H is the net head in ft, and Eff

is the efficiency of the dam turbine. The net head for each dam was calculated as the difference

between the reservoir and tailwater elevations (see Appendix B) and the turbine efficiency was

set to 95% for all dams.

III.4 Fish Protection Requirements

Since 1995, the Seattle City Light dams have been subject to a Federal Energy Regulatory

Commission (FERC) fisheries settlement agreement (No. 553) to manage the 15 mile river reach

between Gorge Dam and the inflow of the Cascade River at Marblemount, WA (FERC, 2011).

The goal is 100% protection of spawning fish via two methods:

Slower downramping of flows from the daily hydropower production cycle Maintaining minimum stream flows during the fish spawning periods

The intent is to prevent the dewatering of redds or stranding of frys during the spawning

periods. The model incorporates the minimum stream flow requirements in the agreement by

calculating the daily spawning flow for three species (Steelhead, Chinook, and Chum salmon)

via Equation 3.

DSF = ANF Max (RDF, RDL) Max(0, SS TSS) [3]

Where DSF is the daily spawning flow at Newhalem, WA, ANF is the regulated flow at

Newhalem, WA, RDF is the flood control release from Ross Dam, RDL is the hydropower release

to meet the energy targets, SS is the incremental inflow between Ross and Gorge Dam, and TSS

is the incremental inflow threshold for each spawning period, in cfs. The highest 10-day average


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daily spawning flow was then used to determine the corresponding minimum stream flow

below Gorge Dam for each species from pre-calculated tables (see Appendix C). The necessary

releases were determined from largest minimum flow required to protect fish during the

spawning period, which were set at Apr. 1st

to 30th

for Steelhead, Aug. 20th

to Oct. 15th

for

Chinook salmon, and Nov. 1

st

to Jan. 6

th

for Chum salmon.

III.5 Sediment Loading

The sediment loading was calculated using the linear regression of suspended sediment loading

as a function of flow at Mt. Vernon, WA (Curran, Grossman, Mastin, & Huffman, 2012) given in

Equation 4.

Qs = 1.29x10-3

Qw2.39

[4]

Where Qs is the suspended sediment discharge in metric tons per day and Qw is the water

discharge in cubic meters per second at Mt. Vernon, WA.

III.6 Model Calibration

Calibrating the model involved matching the Ross, Upper, and Lower Baker dam simulated

reservoir elevations to observed historical elevations between water years 1916 and 2006. This

was achieved by multiplying the monthly hydropower energy targets by an annual adjustment

factor (see Appendix A) to account for the variation between wetter and drier years. First, a set

of static adjustment factors were estimated by visually matching the simulated elevations to

the observed record. An additional set of dynamic adjustment factors were estimated by

linearly regressing the April to September flows at Ross Dam to the visually matched set of

static factors for the water years 1986 to 2006. These dynamic factors were then extrapolated

to the full historical time period (19162006) in addition to the predicted 2040s and 2080s

flows under the climate change scenarios.

IV. Model Validation

The comparison of the Ross and Upper Baker reservoir elevations for the historically observed,

static, and dynamic adjustment factor simulations for the Oct 1st

, 1985 to Sep 30th

, 2006 time

period are shown in Figure 3 and Figure 4. Since the adjustment factor for the previous year can

affect the reservoir elevation of the subsequent year when the reservoir is not fully refilled,

emphasis was given to err on the side of higher reservoir elevations when possible. The

simulations for the Upper Baker reservoir did a better job of achieving both a closer match to

the observed elevations and ensuring full annual reservoir recharge than the Ross reservoir.

Additionally, while the static adjustment factors more closely match the observed record, the

dynamic factors are more useful for the climate change scenarios since future flows are likely to

be quite different from the historical record.


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Figure 3: Validation of SCL adjustment factors using Ross Dam Reservoir elevations

Figure 4: Validation of PSE adjustment factors using Upper Baker Reservoir elevations

1,460

1,480

1,500

1,520

1,540

1,560

1,580

1,600

1,620

25,569 26,569 27,569 28,569 29,569 30,569 31,569 32,569

RossDamR

eservoirEleva

tion(ft)

Day

Historic Static Dynamic Max

650

660

670

680

690

700

710

720

730

740

25,569 26,569 27,569 28,569 29,569 30,569 31,569 32,569

UpperBakerReservoirElevation(ft)

Day

Historic Static Dynamic Max


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Finally, the dynamic adjustment factor simulated values for Ross and Upper Baker reservoir

elevations were compared to the flow at Concrete, WA during two flood events (i.e. the flow

exceeded the flood control target) on Nov. 9th

-11th

, 1989 and Nov. 12th

-13th

, 1999, shown in

Figure 5. As expected, stream flows at Concrete, WA above the flood control target of 62,500

cfs correspond with increases in the Ross and Upper Baker reservoir elevations, indicating thatthe model is correctly implementing flood control operations at the dams.

Figure 5: Validation of model by comparing reservoir elevation and Concrete, WA flows during two flood events

during Nov. 9th-11th, 1989 (left) and Nov. 12th-13th, 1999 (right)

V. Results and Discussion

Figure 6 and Figure 7show the effect of the 2040s and 2080s climate change scenario

simulations on the elevations on the Ross and Upper Baker dam reservoirs. In particular, both

reservoirs trend closer towards the full reservoir volume under climate change, indicating that

the reservoirs are being used to store a greater volume of inflows for more of the year. By the

2080s the Upper Baker reservoir is even predicted to rarely drop below the elevation specifiedby the dams flood control rule curve.


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Figure 6: Ross Dam reservoir elevations for simulated historic and climate change scenarios

Figure 7: Upper Baker Dam reservoir elevations for simulated historic and climate change scenarios

1,460

1,480

1,500

1,520

1,540

1,560

1,580

1,600

1,620

25204 26204 27204 28204 29204 30204 31204 32204 33204

RossReservoirElevatio

n(ft)

DaySimulated Historic Simulated 2040s Simulated 2080s Max Elevation

650

660

670

680

690

700

710

720

730

740

25,204 26,204 27,204 28,204 29,204 30,204 31,204 32,204 33,204

UpperBakerReservoirElevation(ft)

DaySimulated Historic Simulated 2040s Simulated 2080s Max Elevation


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The CDFs of the peak and 7-day average low flows at Gorge Dam and Mt. Vernon, WA are

plotted in Figure 8. For the peak flows, the model simulation shows that the severity of the

highest flows will increase under climate change. However, the effects on the 7-day average

low flows are less clear. The average low flows for Gorge Dam show a flattening of the CDF,

indicating a reduction in the variability between the annual low flow extremes. However, theCDF for the Mt. Vernon low flows more uniform increase in the severity of the 7-day average

low flows by the 2080s climate change scenario in addition to a modest reduction in the annual

variability.

Figure 8: CDFs for the peak (left) and 7-day average low flows (right) at Gorge Dam (top) and Mt. Vernon, WA

(bottom)

Figure 9 gives the long-term monthly average of suspended sediment loading at Mt. Vernon,WA and indicates both a shift in the peak monthly flow towards the winter months and an

increase in the total sediment flow, rising from a long-term annual average of 1.7 million metric

tons in the historic simulations, to 2.3 and 3.1 million metric tons in the 2040s and 2080s

simulations, respectively. This increase can also be seen in Figure 10 in which the simulations

incorporating the climate change scenarios show consistently higher annual sediment loading

that follows the trend of the historic simulation.


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Figure 9: Long term monthly average suspended sediment flow at Mt. Vernon, WA for the simulated historic and

climate change scenarios

Figure 10: Annual suspended sediment flow at Mt. Vernon, WA for the simulated historic and climate change

scenarios

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

Oct Sep Nov Dec Jan Feb Mar Apr May Jun Jul Aug

Longterma

veragesedimentflo

w

(metric

tons/month)

Historic Simulation 2040s Simulation 2080s Simulation

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

8,000,000

9,000,000

0 10 20 30 40 50 60 70 80

Annualsedimentflow

(metricton

s/year)

Simulation Water Year

Historic Simulation 2040s Simulation 2080s Simulation


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VI. Summary and Conclusions

The trend towards more severe peak and low flows in the Skagit River under climate change

has several implications towards water management in the river basin. In particular, current

flood control operations may be insufficient towards reducing flooding due to increased peak

inflows from unmanaged tributaries such as the Sauk and Cascade Rivers. Additionally, theprimary flood control reservoirs behind Ross and Upper Baker dam are predicted to be

operated at higher elevations, potentially making it more difficult to implement additional flood

control storage in the future, if desired.

A strong correlation is seen between the long-term monthly average streamflows and sediment

loading at Mt. Vernon, WA (See Appendix D) suggesting that higher peak flows will lead to

increased sediment flow in the river delta, which is consistent with Czuba et al (2011)

observation that peak sediment loading typically occurs during floods. Additionally, the timing

in the peak flows translates in to a shift in the long-term monthly sediment loading from a dual

peaks in September and May (historical simulation) to a single peak in December (2080s

simulation). The result is consistent with the river basin moving towards a more rain-dominant

system of precipitation.

While low flows are predicted to be more severe under climate change, the simulations indicate

that the annual variability in extreme low flows may be lessened. One possible explanation is

that the greater expected reservoir storage volumes predicted in the 2040s and 2080s are

sufficient enough to mitigate some of the low flow extremes. This effect is particularly

noticeable at Gorge Dam, in which Seattle City Light is under agreement to maintain minimum

streamflows to protect spawning fish. However, reservoir storage may not be sufficient to

maintain the same level protection at Mt. Vernon, WA due the contribution of unmanaged

tributaries.

Overall, the model simulation indicates management of the existing dams on the Skagit River

may become more insufficient to moderating the effects of climate change on the river basins

hydrology. The contributions of the unmanaged tributaries to extreme flows and sediment

loading are predicted to become more important in producing undesired conditions at

downstream sites such as Concrete and Mt. Vernon, WA. Of particular interest is the

uncertainty as to whether the increased loading and shift in timing of sediment at Mt. Vernon,

WA will be a net benefit or drawback to the river delta, as additional sediment loading can

offset coastal erosion due to rising sea levels.


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References

Anderson, B., Gibbs, M., Hart, C., Inman, R., McChesney, D., & Slattery, K. (2006). 2005 Drought

Response Report to the Legislature. Olympia, WA: Department of Ecology.

Curran, C. A., Grossman, E. E., Mastin, M. C., & Huffman, R. L. (2012). Sediment load and distribution in

the Lower Skagit River, Washington, USA. Tacoma, WA: Washington Water Science Center.

Czuba, J. A., Magirl, C. S., Czuba, C. R., Grossman, E. E., Curran, C. A., Gendaszek, A. S., et al. (2011).

Sediment Load from Major Rivers into Puget Sound and its Adjacent Waters. Tacoma, WA: USGS.

FERC. (2011). Skagit River Hydroelectric Project: Revised Fisheries Settlement Agreement. Washington,

DC: Federal Energy Regulatory Commission.

Hamlet, A. F., Lee, S.-Y., Mantua, N. J., Salathe, Jr, E. P., Snover, A. K., Steed, R., et al. (2010). Seattle City

Light Climate Change Analysis. Seattle, WA: University of Washington.

Lee, S.-Y., & Hamlet, A. F. (2011).Skagit River Basin Climate Science Report.

University of Washington,

Civil and Environmental Engineering. Seattle, WA: Skagit Country.

USACE. (1985). Baker River Project Upper Baker Development Flood Control Rule Curve. Seattle, WA: U.S.

Army Corps of Engineers.

USACE. (1995). Skagit River Project Ross Reservoir Flood Control Rule Curve. Seattle, WA: U.S. Army

Corps of Engineers.


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Appendix A: Static and Dynamic Energy Target Fractions

Table A1: Data for dynamic energy target fraction regressions

Apr-Sept Flow (cfs)

Ross Dam Ross Dam Upper Baker Dam

1986 4,169 0.95 0.68

1987 4,208 1.07 1.01

1988 3,915 0.72 0.5

1989 4,861 1.22 0.94

1990 4,762 1.23 1.06

1991 4,919 1.37 1.06

1992 3,402 0.95 0.9

1993 3,888 0.75 0.6

1994 3,299 0.80 0.8

1995 4,406 - 0.98

1996 4,656 - 0.9

1997 7,692 - 1.23

1998 3,856 - 1.04

1999 6,952 1.25 1.08

2000 5,700 1.22 0.9

2001 3,463 0.77 0.712002 5,142 1.30 1.02

2003 3,469 0.72 -

2004 4,518 1.12 -

2005 3,815 0.92 -

2006 4,627 1.20 -

Water YearEnergy Target Fraction

Figure A1: Linear regression of energy target fractions

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000

EnergyTargetFraction

Ross Dam Apr-Sept Flow (cfs)

Ross Upper Baker


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The linear regression of the energy target fraction for Ross Dam (R2

= 0.6006) and Upper Baker

Dam (R2

= 0.4075) are given in Equation A1 and A2, respectively.

ETFRoss = 0.000184 (ASFRoss) + 0.222 [A1]

ETFUpperBaker = 0.000102(ASFRoss) + 0.430 [A2]

Where ETFRoss is the annual energy target fraction for Ross Dam, ETFUpperBaker is the annual

energy target fraction for Upper Baker Dam, and ASFRoss is the annual April to September flow

at Ross Dam, in cfs.


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Table A2: Static and dynamic energy target fractions for 1916 to 2006 for the Seattle City Light and Puget Sound

Energy projectsApr-Sept Flow (cfs)

Static Dynamic Static Dynamic

1916 7,239 1.55 1.55 1.17 1.17

1917 5,469 1.22 1.23 0.98 0.99

1918 6,161 1.35 1.35 1.05 1.06

1919 4,812 1.1 1.11 0.91 0.92

1920 4,109 0.97 0.98 0.84 0.85

1921 4,961 1.13 1.13 0.93 0.94

1922 4,199 0.99 0.99 0.85 0.86

1923 4,653 1.07 1.08 0.9 0.91

1924 3,626 0.88 0.89 0.79 0.80

1925 4,660 1.07 1.08 0.9 0.91

1926 3,254 0.81 0.82 0.75 0.76

1927 4,309 1.01 1.01 0.86 0.87

1928 4,645 1.07 1.07 0.9 0.90

1929 2,974 0.76 0.77 0.72 0.73

1930 2,909 0.75 0.76 0.71 0.73

1931 3,988 0.95 0.95 0.83 0.84

1932 5,673 1.26 1.26 1 1.01

1933 6,003 1.32 1.32 1.04 1.04

1934 5,629 1.25 1.26 1 1.01

1935 4,913 1.12 1.12 0.92 0.93

1936 4,895 1.12 1.12 0.92 0.93

1937 4,366 1.02 1.02 0.87 0.88

1938 4,607 1.06 1.07 0.89 0.90

1939 4,484 1.04 1.05 0.88 0.89

1940 3,303 0.82 0.83 0.75 0.77

1941 2,837 0.74 0.74 0.71 0.72

1942 3,059 0.78 0.78 0.73 0.74

1943 4,263 1 1.00 0.86 0.87

1944 3,092 0.78 0.79 0.73 0.75

1945 4,295 1 1.01 0.86 0.87

1946 5,727 1.27 1.27 1.01 1.021947 4,985 1.13 1.14 0.93 0.94

1948 6,187 1.35 1.36 1.06 1.06

1949 5,400 1.21 1.21 0.97 0.98

1950 6,589 1.43 1.43 1.1 1.10

1951 5,118 1.16 1.16 0.95 0.95

1952 3,910 0.93 0.94 0.82 0.83

1953 4,365 1.02 1.02 0.87 0.88

1954 5,645 1.25 1.26 1 1.01

1955 4,788 1.1 1.10 0.91 0.92

1956 6,327 1.38 1.38 1.07 1.08

1957 4,846 1.11 1.11 0.92 0.93

1958 3,801 0.91 0.92 0.81 0.82

1959 6,442 1.4 1.40 1.08 1.09

1960 4,818 1.1 1.11 0.91 0.921961 5,073 1.15 1.15 0.94 0.95

1962 4,041 0.96 0.96 0.83 0.84

1963 3,294 0.82 0.83 0.75 0.77

1964 5,900 1.3 1.31 1.03 1.03

1965 5,833 1.29 1.29 1.02 1.03

1966 4,623 1.07 1.07 0.89 0.90

1967 5,234 1.18 1.18 0.96 0.96

1968 4,627 1.07 1.07 0.89 0.90

1969 5,178 1.17 1.17 0.95 0.96

Water Year Energy Target Fraction

Ross Dam Seattle City Lights Project Puget Sound Energy Project


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Apr-Sept Flow (cfs)

Static Dynamic Static Dynamic

1970 3,782 0.91 0.92 0.8 0.82

1971 6,795 1.47 1.47 1.12 1.12

1972 7,777 1.65 1.65 1.22 1.22

1973 3,707 0.9 0.90 0.8 0.81

1974 7,046 1.51 1.52 1.15 1.15

1975 5,286 1.19 1.19 0.96 0.97

1976 6,326 1.38 1.38 1.07 1.08

1977 2,756 0.72 0.73 0.7 0.71

1978 4,550 1.05 1.06 0.89 0.89

1979 3,689 0.89 0.90 0.8 0.81

1980 4,491 1.04 1.05 0.88 0.89

1981 3,611 0.88 0.88 0.79 0.80

1982 5,556 1.24 1.24 0.99 1.00

1983 4,796 1.1 1.10 0.91 0.92

1984 4,770 1.09 1.10 0.91 0.92

1985 4,244 0.9 1.00 0.7 0.86

1986 4,169 0.95 0.99 0.68 0.86

1987 4,208 1.07 0.99 1.01 0.86

1988 3,915 0.72 0.94 0.5 0.831989 4,861 1.22 1.11 0.94 0.93

1990 4,762 1.23 1.10 1.06 0.92

1991 4,919 1.37 1.12 1.06 0.93

1992 3,402 0.95 0.85 0.9 0.78

1993 3,888 0.75 0.94 0.6 0.83

1994 3,299 0.8 0.83 0.8 0.77

1995 4,406 1.03 1.03 0.98 0.88

1996 4,656 1.07 1.08 0.9 0.91

1997 7,692 1.63 1.63 1.23 1.22

1998 3,856 0.92 0.93 1.04 0.82

1999 6,952 1.25 1.50 1.08 1.14

2000 5,700 1.22 1.27 0.9 1.01

2001 3,463 0.77 0.86 0.71 0.78

2002 5,142 1.3 1.17 1.02 0.962003 3,469 0.72 0.86 0.77 0.78

2004 4,518 1.12 1.05 0.88 0.89

2005 3,815 0.92 0.92 0.81 0.82

2006 4,627 1.2 1.07 0.89 0.90

Water Year Energy Target Fraction

Ross Dam Seattle City Lights Project Puget Sound Energy Project


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Appendix B: Estimation of Reservoir Elevations

The tailwater elevations are the Diablo reservoir elevation, 870 ft, 492.9 ft, 442.75 ft, and 172.5

ft for Ross, Diablo, Gorge, Upper, and Lower Baker reservoirs, respectively. The reservoir

elevations for Ross, Diablo, and Gorge are given in Equations B1, B2, and B3. The reservoirelevation for Upper and Lower Baker are interpolated from the values specified in Table B1.

ERoss = 2.79x10-27

(VRoss)5 7.42x10

-21(VRoss)

4+ 7.87x10

-

15(VRoss)

3 4.28x10

-9(VRoss)

2+ 1.42x10

-3(VRoss) + 1.31x10

3

[B1]

Where ERoss is the elevation of Ross reservoir, in ft, and VRoss is the storage volume of Ross

reservoir, in cfs-d.

EDiablo = -2.23x10-22

*(VDiablo)5

+ 2.35x10-17

(VDiablo)4

+ 2.01x10-

13(VDiablo)

3 1.32x10

-7(VDiablo)

2+ 8.85x10

-3(VDiablo) + 1.00x10

3

[B2]

Where EDiablo is the elevation of Diablo reservoir, in ft, and VDiablo is the storage volume of Diabloreservoir, in cfs-d.

EGorge = 1.50x10-16

(VGorge)5

- 2.03x10-12

(VGorge)4

+ 1.08x10-

08(VGorge)

3- 3.08x10

-05(VGorge)

2+ 6.39x10

-2(VGorge) +

7.84x102

[B3]

Where EGorge is the elevation of Gorge reservoir, in ft, and VGorge is the storage volume of Gorge

reservoir, in cfs-d.


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Table B1: Upper and Lower Baker Reservoir elevations corresponding to each storage volumesE l e v a t i o n (f t )

U p p e r B a k e r L o w e r B a k e r U p p e r B a k e r L o w e r B a k e r U p p e r B a k e r

0 471. 64 343. 75 46, 500 676. 00 415. 00 93, 000 707. 00

500 525. 00 344. 00 47, 000 677. 00 416. 00 93, 500 707. 00

1, 000 535. 00 346. 00 47, 500 677. 77 416. 00 94, 000 708. 00

1, 500 545. 00 347. 00 48, 000 678. 00 417. 00 94, 500 708. 00

2, 000 550. 00 348. 00 48, 500 678. 00 417. 00 95, 000 708. 00

2, 500 560. 00 349. 00 49, 000 679. 00 418. 00 95, 500 708. 00

3, 000 565. 00 350. 00 49, 500 679. 00 418. 00 96, 000 709. 00

3, 500 570. 00 351. 00 50, 000 679. 00 419. 00 96, 500 709. 00

4, 000 570. 00 352. 00 50, 500 680. 00 419. 00 97, 000 709. 00

4, 500 575. 00 354. 00 51, 000 680. 00 420. 00 97, 500 709. 00

5, 000 580. 00 355. 00 51, 500 681. 00 420. 00 98, 000 710. 00

5, 500 585. 00 356. 00 52, 000 681. 00 421. 00 98, 500 710. 00

6, 000 585. 00 357. 00 52, 500 682. 00 422. 00 99, 000 710. 00

6, 500 590. 00 358. 00 53, 000 682. 00 422. 00 99, 500 710. 00

7, 000 590. 00 359. 00 53, 500 682. 00 423. 00 100, 000 711. 00

7, 500 595. 00 360. 00 54, 000 683. 00 423. 00 100, 500 711. 00

8, 000 595. 00 361. 00 54, 500 683. 00 424. 00 101, 000 711. 56

8, 500 602. 00 362. 00 55, 000 684. 00 424. 00 101, 500 711. 56

9, 000 604. 00 363. 00 55, 500 684. 00 425. 00 102, 000 712. 00

9, 500 605. 00 364. 00 56, 000 684. 00 425. 00 102, 500 712. 00

10, 000 607. 00 365. 00 56, 500 685. 00 426. 00 103, 000 712. 00

10, 500 609. 00 365. 00 57, 000 685. 00 426. 00 103, 500 712. 00

11, 000 611. 00 366. 00 57, 500 685. 00 427. 00 104, 000 713. 00

11, 500 612. 00 367. 00 58, 000 686. 00 427. 00 104, 500 713. 00

12, 000 614. 00 368. 00 58, 500 686. 00 428. 00 105, 000 713. 00

12, 500 615. 00 369. 00 59, 000 687. 00 428. 55 105, 500 713. 00

13, 000 617. 00 370. 00 59, 500 687. 00 429. 00 106, 000 713. 00

13, 500 619. 00 371. 00 60, 000 687. 00 429. 00 106, 500 714. 00

14, 000 620. 00 372. 00 60, 500 688. 00 430. 00 107, 000 714. 00

14, 500 621. 00 373. 00 61, 000 688. 00 430. 00 107, 500 714. 00

15, 000 623. 00 373. 75 61, 500 688. 00 431. 00 108, 000 714. 00

15, 500 624. 00 374. 00 62, 000 689. 00 431. 00 108, 500 715. 00

16, 000 626. 00 375. 00 62, 500 689. 00 432. 00 109, 000 715. 00

16, 500 627. 00 376. 00 63, 000 689. 00 432. 00 109, 500 715. 00

17, 000 628. 00 377. 00 63, 500 690. 00 433. 00 110, 000 715. 00

17, 500 629. 00 378. 00 64, 000 690. 00 433. 00 110, 500 716. 00

18, 000 631. 00 378. 00 64, 500 690. 00 433. 00 111, 000 716. 00

18, 500 632. 00 379. 00 65, 000 691. 00 434. 00 111, 500 716. 00

19, 000 633. 00 380. 00 65, 500 691. 00 434. 00 112, 000 716. 00

19, 500 634. 00 381. 00 66, 000 691. 00 435. 00 112, 500 716. 00

20, 000 636. 00 382. 00 66, 500 692. 00 435. 00 113, 000 717. 00

20, 500 637. 00 382. 00 67, 000 692. 00 436. 00 113, 500 717. 00

21, 000 638. 00 383. 00 67, 500 692. 00 436. 00 114, 000 717. 00

21, 500 639. 00 384. 00 68, 000 693. 00 437. 00 114, 500 717. 00

22, 000 640. 00 385. 00 68, 500 693. 00 437. 00 115, 000 718. 00

22, 500 641. 00 385. 00 69, 000 693. 00 438. 00 115, 500 718. 00

23, 000 643. 00 386. 00 69, 500 694. 00 438. 00 116, 000 718. 00

23, 500 644. 00 387. 00 70, 000 694. 00 439. 00 116, 500 718. 00

24, 000 645. 00 387. 00 70, 500 694. 00 439. 00 117, 000 718. 00

24, 500 646. 00 388. 00 71, 000 695. 00 439. 00 117, 500 719. 00

25, 000 647. 00 389. 00 71, 500 695. 00 440. 00 118, 000 719. 00

25, 500 648. 00 389. 00 72, 000 695. 00 440. 00 118, 500 719. 00

26, 000 649. 00 390. 00 72, 500 696. 00 441. 00 119, 000 719. 00

26, 500 650. 00 391. 00 73, 000 696. 00 441. 00 119, 500 720. 00

27, 000 651. 00 392. 00 73, 500 696. 00 442. 00 120, 000 720. 00

27, 500 652. 00 392. 00 74, 000 697. 00 442. 35 120, 500 720. 00

28, 000 653. 00 393. 00 74, 500 697. 00 - 121, 000 720. 00

28, 500 654. 00 393. 00 75, 000 697. 00 - 121, 500 720. 00

29, 000 655. 00 394. 00 75, 500 697. 77 - 122, 000 721. 00

29, 500 656. 00 395. 00 76, 000 698. 00 - 122, 500 721. 00

30, 000 657. 00 395. 00 76, 500 698. 00 - 123, 000 721. 00

30, 500 658. 00 396. 00 77, 000 698. 00 - 123, 500 721. 00

31, 000 658. 77 397. 00 77, 500 699. 00 - 124, 000 721. 00

31, 500 659. 00 397. 00 78, 000 699. 00 - 124, 500 722. 00

32, 000 660. 00 398. 00 78, 500 699. 00 - 125, 000 722. 00

32, 500 661. 00 399. 00 79, 000 699. 00 - 125, 500 722. 00

33, 000 662. 00 399. 00 79, 500 700. 00 - 126, 000 722. 00

33, 500 662. 00 400. 00 80, 000 700. 00 - 126, 500 722. 00

34, 000 663. 00 400. 00 80, 500 700. 00 - 127, 000 723. 00

34, 500 664. 00 401. 00 81, 000 701. 00 - 127, 500 723. 00

35, 000 664. 00 402. 00 81, 500 701. 00 - 128, 000 723. 00

35, 500 665. 00 402. 00 82, 000 701. 00 - 128, 500 723. 00

36, 000 665. 00 403. 00 82, 500 701. 00 - 129, 000 724. 00

36, 500 666. 00 403. 00 83, 000 702. 00 - 129, 500 724. 00

37, 000 667. 00 404. 00 83, 500 702. 00 - 130, 000 724. 00

37, 500 667. 00 405. 00 84, 000 702. 00 - 130, 500 724. 00

38, 000 668. 00 405. 00 84, 500 703. 00 - 131, 000 724. 00

38, 500 668. 00 406. 00 85, 000 703. 00 - 131, 500 725. 00

39, 000 669. 00 406. 00 85, 500 703. 00 - 132, 000 725. 00

39, 500 670. 00 407. 00 86, 000 703. 00 - 132, 500 725. 00

40, 000 670. 00 408. 00 86, 500 704. 00 - 133, 000 725. 00

40, 500 671. 00 408. 00 87, 000 704. 00 - 133, 500 725. 00

41, 000 671. 00 409. 00 87, 500 704. 00 - 134, 000 726. 00

41, 500 672. 00 409. 00 88, 000 705. 00 - 134, 500 726. 00

42, 000 672. 00 410. 00 88, 500 705. 00 - 135, 000 726. 00

42, 500 673. 00 411. 00 89, 000 705. 00 - 135, 500 726. 00

43, 000 673. 00 411. 00 89, 500 705. 00 - 136, 000 726. 00

43, 500 674. 00 412. 00 90, 000 706. 00 - 136, 500 727. 00

44, 000 674. 00 412. 00 90, 500 706. 00 - 137, 000 727. 00

44, 500 675. 00 413. 00 91, 000 706. 00 - 137, 500 727. 00

45, 000 675. 00 413. 00 91, 500 706. 00 - 138, 000 727. 00

45, 500 676. 00 414. 00 92, 000 707. 00 - 138, 500 727. 77

46, 000 676. 00 414. 00 92, 500 707. 00 -

S t o r a g e V o l u m e

( c f s - d )

E l e v a t i o n ( f t ) S t o r a g e V o l u me

( c f s - d )

E l e v a t i o n ( f t ) S t o r a g e V o l u me

( c f s - d )


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Appendix C: Minimum fish flow requirements

Table C1: Chinook salmon minimum flows based on daily spawning flows

Chinook Salmon

Daily Spawning Flow (cfs) Aug Sep Oct Nov Dec Jan Feb Mar Apr

2, 00 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 000 1,0 00 1, 80 0 1 ,8 00 1, 80 0

2, 10 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 000 1,0 00 1, 80 0 1 ,8 00 1, 80 0

2, 20 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 000 1,0 00 1, 80 0 1 ,8 00 1, 80 0

2, 30 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 100 1,1 00 1, 80 0 1 ,8 00 1, 80 0

2, 40 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 100 1,1 00 1, 80 0 1 ,8 00 1, 80 0

2, 50 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 200 1,2 00 1, 80 0 1 ,8 00 1, 80 0

2, 60 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 300 1,3 00 1, 80 0 1 ,8 00 1, 80 0

2, 70 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 300 1,3 00 1, 80 0 1 ,8 00 1, 80 0

2, 80 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 400 1,4 00 1, 80 0 1 ,8 00 1, 80 0

2, 90 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 400 1,4 00 1, 80 0 1 ,8 00 1, 80 0

3 ,00 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 400 1,4 00 1, 80 0 1 ,8 00 1, 80 0

3 ,10 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 500 1,5 00 1, 80 0 1 ,8 00 1, 80 0

3 ,20 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 500 1,5 00 1, 80 0 1 ,8 00 1, 80 0

3 ,3 00 2 ,000 1, 50 0 1 ,500 1,0 00 1, 600 1,8 00 1, 80 0 1 ,8 00 1, 80 0

3 ,40 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 700 1,7 00 1, 80 0 1 ,8 00 1, 80 0

3 ,50 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 700 1,7 00 1, 80 0 1 ,8 00 1, 80 03 ,60 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 800 1,8 00 1, 80 0 1 ,8 00 1, 80 0

3 ,70 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 800 1,8 00 1, 80 0 1 ,8 00 1, 80 0

3 ,80 0 2 ,000 1, 50 0 1 ,500 1,0 00 1, 800 1,8 00 1, 80 0 1 ,8 00 1, 80 0

3 ,90 0 2 ,000 1, 50 0 1 ,500 1,1 00 1, 900 1,9 00 1, 80 0 1 ,8 00 1, 80 0

4, 00 0 2 ,000 1, 50 0 1 ,500 1,1 00 2, 000 2,0 00 1, 80 0 1 ,8 00 1, 80 0

4, 10 0 2 ,000 1, 50 0 1 ,500 1,1 00 2, 100 2,1 00 1, 90 0 1 ,8 00 1, 80 0

4, 20 0 2 ,000 1, 50 0 1 ,500 1,2 00 2, 100 2,1 00 1, 90 0 1 ,8 00 1, 80 0

4, 30 0 2 ,000 1, 50 0 1 ,500 1,2 00 2, 200 2,2 00 2, 10 0 1 ,9 00 1, 90 0

4, 40 0 2 ,000 1, 50 0 1 ,500 1,2 00 2, 300 2,3 00 2, 10 0 2 ,0 00 1, 90 0

4, 50 0 2 ,000 1, 50 0 1 ,500 1,3 00 2, 300 2,3 00 2, 20 0 2 ,1 00 2, 00 0

4, 60 0 2 ,000 1, 50 0 1 ,500 1,3 00 2, 400 2,4 00 2, 20 0 2 ,1 00 2, 00 0

4, 70 0 2 ,000 1, 50 0 1 ,500 1,3 00 2, 500 2,5 00 2, 30 0 2 ,2 00 2, 10 0

4, 80 0 2 ,000 1, 50 0 1 ,500 1,3 00 2, 500 2,5 00 2, 40 0 2 ,2 00 2, 20 0

4, 90 0 2 ,000 1, 50 0 1 ,500 1,4 00 2, 500 2,5 00 2, 40 0 2 ,2 00 2, 20 05, 00 0 2 ,000 1, 50 0 1 ,500 1,5 00 2, 600 2,6 00 2, 40 0 2 ,3 00 2, 20 0

5, 10 0 2 ,000 1, 50 0 1 ,600 1,5 00 2, 600 2,6 00 2, 50 0 2 ,3 00 2, 30 0

5, 20 0 2 ,000 1, 50 0 1 ,800 1,6 00 2, 700 2,7 00 2, 50 0 2 ,4 00 2, 40 0

5, 30 0 2 ,000 1, 50 0 1 ,800 1,7 00 2, 700 2,7 00 2, 60 0 2 ,5 00 2, 40 0

5, 40 0 2 ,000 1, 60 0 1 ,900 1,8 00 2, 700 2,7 00 2, 60 0 2 ,5 00 2, 50 0

5, 50 0 2 ,000 1, 70 0 1 ,900 1,9 00 2, 700 2,7 00 2, 60 0 2 ,5 00 2, 50 0

5, 60 0 2 ,000 1, 80 0 2 ,000 1,9 00 2, 900 2,9 00 2, 60 0 2 ,6 00 2, 50 0

5, 70 0 2 ,000 1, 80 0 2 ,000 2,0 00 3, 100 3,1 00 2, 90 0 2 ,8 00 2, 70 0

5, 80 0 2 ,000 1, 90 0 2 ,000 2,0 00 3, 100 3,1 00 2, 90 0 2 ,8 00 2, 70 0

5, 90 0 2 ,000 1, 90 0 2 ,100 2,0 00 3, 100 3,1 00 3, 00 0 3 ,0 00 2, 90 0

6, 00 0 2 ,000 1, 90 0 2 ,100 2,0 00 3, 100 3,1 00 3, 00 0 3 ,0 00 2, 90 0

6, 10 0 2 ,000 2, 00 0 2 ,100 2,1 00 3, 100 3,1 00 3, 00 0 3 ,0 00 2, 90 0

6, 20 0 2 ,000 2, 00 0 2 ,100 2,1 00 3, 200 3,2 00 3, 10 0 3 ,0 00 2, 90 0

6, 30 0 2 ,000 2, 00 0 2 ,400 2,3 00 3, 400 3,4 00 3, 10 0 3 ,0 00 2, 90 06, 40 0 2 ,100 2, 00 0 2 ,400 2,4 00 3, 400 3,4 00 3, 20 0 3 ,0 00 2, 90 0

6, 50 0 2 ,100 2, 20 0 2 ,400 2,4 00 3, 500 3,5 00 3, 30 0 3 ,1 00 3, 00 0

6, 60 0 2 ,200 2, 30 0 2 ,600 2,5 00 3, 700 3,7 00 3, 40 0 3 ,2 00 3, 10 0

6, 70 0 2 ,200 2, 30 0 2 ,700 2,5 00 4, 000 4,0 00 3, 60 0 3 ,3 00 3, 10 0

6, 80 0 2 ,500 2, 30 0 2 ,800 2,6 00 4, 000 4,0 00 3, 80 0 3 ,5 00 3, 10 0

6, 90 0 2 ,500 2, 40 0 2 ,800 2,7 00 4, 000 4,0 00 3, 80 0 3 ,7 00 3, 60 0

7, 00 0 2 ,500 2, 60 0 2 ,800 2,7 00 4, 100 4,1 00 3, 90 0 3 ,9 00 3, 80 0

Min instantaneous incubation flow (cfs)


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Table C2: Chum salmon minimum flows based on daily spawning flows

Chum Salmon

Daily Spawning Flow (cfs) Nov Dec Jan Feb Mar Apr May

3 ,00 0 2, 10 0 1, 800 1, 000 1, 80 0 1 ,8 00 2, 10 0 1, 50 0

3 ,10 0 2, 10 0 1, 800 1, 500 1, 80 0 1 ,8 00 2, 10 0 1, 50 0

3 ,20 0 2, 20 0 1, 800 1, 500 1, 80 0 1 ,8 00 2, 10 0 1, 50 0

3,300 2,200 1,800 1,500 1,800 1,800 2,100 1,500

3 ,40 0 2, 20 0 1, 800 1, 800 1, 80 0 2 ,1 00 2, 10 0 1, 50 0

3 ,50 0 2, 20 0 1, 800 2, 200 1, 80 0 2 ,1 00 2, 10 0 1, 50 0

3 ,60 0 2, 20 0 1, 800 2, 200 1, 80 0 2 ,1 00 2, 10 0 1, 50 0

3 ,70 0 2, 20 0 1, 800 2, 200 1, 80 0 2 ,2 00 2, 10 0 1, 50 0

3 ,80 0 2, 20 0 1, 800 2, 200 1, 80 0 2 ,2 00 2, 10 0 1, 50 0

3 ,90 0 2, 20 0 1, 800 2, 200 1, 80 0 2 ,2 00 2, 10 0 1, 50 0

4, 00 0 2, 20 0 1, 800 2, 200 1, 80 0 2 ,2 00 2, 10 0 1, 50 0

4, 10 0 2, 20 0 1, 800 2, 200 1, 90 0 2 ,3 00 2, 20 0 1, 50 0

4,200 2,200 1,800 2,300 1,900 2,3 00 2,200 1,500

4,300 2,200 1,900 2,400 1,900 2,3 00 2,200 1,500

4, 40 0 2, 20 0 1, 900 2, 400 1, 90 0 2 ,3 00 2, 20 0 1, 50 0

4,500 2,200 2,100 2,400 2,000 2,3 00 2,300 1,600

4, 60 0 2, 20 0 2, 100 2, 600 2, 30 0 2 ,6 00 2, 50 0 1, 60 0

4, 70 0 2, 20 0 2, 100 2, 800 2, 50 0 2 ,8 00 2, 60 0 1, 70 0

4, 80 0 2, 20 0 2, 100 2, 900 2, 60 0 2 ,8 00 2, 60 0 1, 80 0

4, 90 0 2, 40 0 2, 200 3 ,000 2, 60 0 2 ,9 00 2, 80 0 1, 90 0

5, 00 0 2, 60 0 2, 200 3 ,000 2, 60 0 2 ,9 00 2, 80 0 1, 90 0

5,100 2,600 2,500 3,000 2,600 3 ,000 2,800 1,900

5,200 2,600 2,500 3,000 2,600 3 ,000 2,900 1,900

5,300 2,600 2,500 3,000 2,600 3 ,100 3,000 2,100

5,400 2,800 2,500 3,200 2,800 3 ,3 00 3,100 2,100

5,500 2,900 2,500 3,200 2,800 3 ,3 00 3,100 2,200

5,600 3,000 2,500 3,200 2,800 3 ,3 00 3,100 2,200

5,700 3,000 2,600 3,200 3,000 3 ,500 3,300 2,300

5,800 3,000 2,700 3,400 3,000 3 ,500 3,300 2,400

5,900 3,300 2,800 3,400 3,000 3 ,500 3,300 2,500

6,000 3,400 3,100 3,400 3,000 3 ,500 3,300 2,700

6,100 3,500 3,200 3,500 3,000 3 ,700 3,600 2,900

6,200 3,500 3,200 3,500 3,300 3 ,900 3,700 2,9006,300 3,800 3,200 4,100 3,700 4,000 4,000 3,000

6,400 4,000 3,3 00 4,100 3,700 4,000 4,000 3,300

6,500 4,200 3,3 00 4,100 3,700 4,100 4,100 3,500

6,600 4,200 3,800 4,100 3,800 4,400 4,300 3,600

6,700 4,300 3,800 4,200 3,800 4,400 4,300 3,600

6,800 4,600 3,900 4,200 4,100 4,700 4,500 3,700

6, 90 0 4, 60 0 4, 000 4, 700 4, 20 0 4 ,8 00 4, 50 0 3 ,70 0

7, 00 0 4, 60 0 4, 000 4, 700 4, 20 0 4 ,8 00 4, 50 0 3 ,80 0



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Table C3: Steelhead minimum flows based on daily spawning flows

April Steelhead

Daily Spawning Flow (cfs) Apr May Jun* Jul*

3,000 1,800 1,500 3,584 3,623

3,100 1,800 1,700 3,684 3,623

3,200 1,800 1,900 3,784 3,623

3,300 1,800 1,900 3,884 3,623

3,400 1,800 1,900 3,984 3,623

3,500 1,800 1,900 4,084 3,623

3,600 1,800 1,900 4,084 3,643

3,700 1,800 1,900 4,084 3,663

3,800 1,800 1,900 4,084 3,683

3,900 1,800 1,900 4,084 3,703

4,000 1,800 2,000 4,084 3,723

4,100 1,800 2,100 4,084 3,743

4,200 1,800 2,100 4,084 3,763

4,300 1,800 2,200 4,084 3,783

4,400 1,800 2,200 4,084 3,803

4,500 1,800 2,200 4,084 3,823

4,600 1,800 2,200 4,084 3,823

4,700 1,800 2,200 4,084 3,823

4,800 1,800 2,200 4,084 3,823

4,900 1,800 2,200 4,084 3,823

5,000 1,800 2,200 4,084 3,823

5,100 1,900 2,200 4,084 3,823

5,200 1,900 2,200 4,084 3,823

5,300 1,900 2,300 4,084 3,823

5,400 1,900 2,300 4,084 3,823

5,500 1,900 2,300 4,084 3,823

5,600 2,100 2,400 4,284 3,823

5,700 2,200 2,400 4,384 3,823

5,800 2,400 2,400 4,444 3,823

5,900 2,500 2,500 4,564 3,823

6,000 2,500 2,600 4,684 3,823

6,100 2,600 2,600 4,684 3,823

6,200 2,600 2,600 4,684 3,8236,300 2,600 2,600 4,684 3,823

6,400 2,600 2,600 4,684 3,823

6,500 2,600 2,600 4,684 3,823


*Predicted flow at Marblemount, WA


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Appendix D: Correlation between long-term monthly stream and sediment flow

Figure D1: Long term monthly sediment flow vs streamflow at Mt. Vernon, WA

y = 0.5483x - 131243

R = 0.8052

y = 0.7905x - 220154

R = 0.7761y = 1.036x - 296801

R = 0.885

-200,000

0

200,000

400,000

600,000

800,000

1,000,000

0 200,000 400,000 600,000 800,000 1,000,000 1,200,000

Longterma

veragem

onthlysedimentflow

(metrictons/m

onth)

Long term average monthly streamflow (cfs/month)

Simulated Historic Simulated 2040s Simulated 2080s

Skagit Project - Final Report - 05072012

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