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Factors for DeclineNOAA (1998)

Habitat Harvest

Disease &

Predation

Regulatory

Mechanisms

Other Natural or Human

Channel form Marine Disease NW Forest Plan Drought

Substrate Recreational Predation Forest Practices Floods

Roughness Scientific Dredge and Fill Ocean Conditions

Estuaries Water Quality Artificial Propagation

Wetlands Ag Practices

Riparian Areas Urban Growth

Water Quality

Streamflows

Passage

Habitat Elimination

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“migration delay resulting from insufficient streamflows or habitat blockage….

loss of usable habitat due to dewatering and blockage….

increased juvenile mortality from increased water temperatures.”

Insufficient Streamflows

1997 NMFS Federal Register

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Current impact of water withdrawals on natural streamflows (August);

Restoration efforts under Oregon Plan;

Change in water withdrawals since onset of Oregon Plan (~1999);

Impact anticipated from future water withdrawals.

Insufficient Streamflows

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Hydrographics Database Measured Stream Flows

Measured Watershed Stream Flow Analysis Calculate Flow Duration

Curves of Natural Stream Flow

Unmeasured Watershed Stream Flow Analysis

Estimate Natural 50 and 80% Exceedance Stream Flows for

Ungaged Streams

In-stream Demands

WAB Stream Flow Database

Natural Stream Flow 50 and 80%

Exceedance Flows Only

Water Rights and Consumptive Use

Information

Storage and Consumptive Use

Demands Estimate Storage and

Consumptive Uses for Water Availability Calculation

Water Availability Calculation

Water Availability Database

50 and 80% Exceedance

Flow Duration Curve Database

Natural Stream Flow Measured Streams Only

Consumptive Use Demands

Estimate Consumptive Uses for Correction of

Measured Stream Flow to Natural Stream Flow

Water Availability Databases

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Flow in stream with no consumptive uses - e.g. 80% exceedance flow

Estimated in one of three ways:1. miscellaneous measurements2. prediction equations based on

measured streamflows3. continuous measurements

All exceedance flows represent same period (1958 to 1987)

Natural Streamflow

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Causes a net reduction in streamflow.

Usually associated with loss via evaporation or transpiration.

Three major categories of consumptive use:

1. Irrigation2. Municipal3. All others (e.g., domestic, livestock) -

Usually small in comparison with stream flow.

Consumptive Use

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Natural Streamflow

...

..1

2

3

4

5

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“Water Availability Basins”

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..

.12

3

4

5

Morr is C

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#

Aug CU (cfs)

3 10

4 3

5 2

Aug CU (cfs)

NSF

(cfs)% CU of NSF

5 25 25%

3 10 30%

2 10 20%

Natural Streamflow

Consumptive Use (CU)

10 - 3 - 2 = 5 cfs

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Water Availability Basins“WABs” in Coastal Coho ESU

North Coast: 164

Mid Coast: 156

Mid-South Coast: 210

Umpqua: 103

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~17 cfs leased

instream

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~16 cfs leased

instream

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Linking Coho Stream Miles to Water Availability Basins

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North Coast TotalCOASTAL COHO ESU: % of Coho Miles by August CU/NSF

0%

25%

50%

75%

100%

ESU NorthCoast

Mid Coast Mid-SouthCoast

Umpqua

% Coho Miles

In Each Category

< 10 % 10 - 40 % 41 - 70 % 71 - 100 % > 100 %

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Water Availability Datasets

Hydrographics Database Measured Stream Flows

Measured Watershed Stream Flow Analysis Calculate Flow Duration

Curves of Natural Stream Flow

Unmeasured Watershed Stream Flow Analysis

Estimate Natural 50 and 80% Exceedance Stream Flows for

Ungaged Streams

In-stream Demands

WAB Stream Flow Database

Natural Stream Flow 50 and 80%

Exceedance Flows Only

Water Rights and Consumptive Use

Information

Storage and Consumptive Use

Demands Estimate Storage and

Consumptive Uses for Water Availability Calculation

Water Availability Calculation

Water Availability Database

50 and 80% Exceedance

Flow Duration Curve Database

Natural Stream Flow Measured Streams Only

Consumptive Use Demands

Estimate Consumptive Uses for Correction of

Measured Stream Flow to Natural Stream Flow

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Preliminary Conclusions

• Consumptive use of water not widespread issue

• Consumptive use generally increases from north to south within the ESU

• Since 1997, streamflow restoration activities coincide with areas of highest consumptive use impacts on streamflow

• Consumptive use not substantially increased since 1999 or likely to increase in future