Yellowtail Dam Modeling Results Brian Marotz Hydropower Mitigation Coordinator

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Yellowtail Dam Modeling Results Brian Marotz Hydropower Mitigation Coordinator

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Yellowtail Dam Modeling Results Brian Marotz Hydropower Mitigation Coordinator. Assumptions for this analysis. Optimize reservoir refill during primary use period. Avoid elevations in the Flood Pool above 3640. Reduce the extent and duration of spill (>8 kcfs). - PowerPoint PPT Presentation

Transcript of Yellowtail Dam Modeling Results Brian Marotz Hydropower Mitigation Coordinator

Page 1: Yellowtail Dam Modeling Results  Brian Marotz Hydropower Mitigation Coordinator

Yellowtail Dam

Modeling Results Brian Marotz

Hydropower Mitigation Coordinator

Page 2: Yellowtail Dam Modeling Results  Brian Marotz Hydropower Mitigation Coordinator

Assumptions for this analysis

• Optimize reservoir refill during primary use period.

• Avoid elevations in the Flood Pool above 3640.

• Reduce the extent and duration of spill (>8 kcfs).

• Reservoir draft targets for each month, January through June, were based on water supply (April through July inflow volume).

• Dam discharges during fall based on similar wateryears and shaped to provide stable fisheries flows for primary river species.

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Eva

cuat

ed S

tora

ge

(KA

F)

April - August Inflow (KAF)

Inflow Water Supply compared to Bighorn Reservoir drawdown

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Monthly Elevation Targets

Based on Inflow Water Supply

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Example of medium-low wateryear

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Not Directly Comparable to GorQ

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Comparison of Bighorn Reservoir Elevations

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1960 1970 1980 1990 2000 2010

Elevations: ft. 1968-2009

Var Q Min El.

VarQ Max El

Hist.Min El.

Hist.Max El.

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1960 1970 1980 1990 2000 2010 2020

Outflows: Kcfs 1968-2009

Hist.Min.

Hist.Max.

VarQ Min.

VarQ Max.

Comparison of Bighorn River Discharges

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Comparison of Rule Curves Comparison of Rule Curves and Historic Operationsand Historic Operations

• Rule curves reduced reservoir drawdown in all except the highest water years.

• Minimized the use of the flood pool, extent and duration.

• Spill was reduced in volume and duration. On.

• Bighorn River discharges remained more stable.

• Extremely low river flows (<1,500 cfs) were avoided.

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Next step:Compare model results andoptimize benefits.