U.S. Bureau of Reclamation

Lahontan Basin Area Office Carson City, NV

Water Supply Outlook January 19, 2016

Presented by: Nadira Kabir, Ph.D., P.E.

Outline

• Current Conditions

• NRCS/RFC Forecasted Data

• Model for Forecasting Basin Outlook

• 2016 Preliminary Outlook

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MARTIS

Nixon

Fernley Derby

Dam

WINNEMUCCA

LAKE (dry)

STAMPEDE

TRUCKEE

RIVER

CARSON

LAKE CARSON

RIVER

LAKE TAHOE

DONNER

Pyramid Lake

Indian Reservation

Stillwater

NWR

LAHONTAN BOCA

INDEPENDENCE

PROSSER

Reno/Sparks Newlands

Project

Carson

City

Fallon

Fallon Indian

Reservation

PYRAMID

LAKE

Tahoe City

WALKER

RIVER

WALKER

LAKE

Walker River

Indian

Reservation Yerington

TOPAZ

LAKE

Schurz

MARBLE BLUFF

TRUCKEE

CANAL

HUMBOLDT

LAKE

TOULON

LAKE

RYE PATCH

RESERVOIR

HUMBOLDT

RIVER

PYRAMID

LAKE

Humboldt Wildlife

Management Area

LOWER HUMBOLDT

REGION

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Water Year 2015 Precipitation % of Normal 10/1/2014 – 3/17/2015

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Current WY Precipitation To Date

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1/19/2016 6

Current Snowpack

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Lake Tahoe Snowpack Per Year

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Great Basin Snowpack January 2015 January 2016

Historical & Forecasted Apr-Jul Runoff by Basin

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Historical & Forecasted A-J Runoff - Truckee

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Historical & Forecasted A-J Runoff - Carson

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RiverWare Modeling for Water

Management Truckee Carson River Model Development:

1.Ops Model: Day-to-day Operation

2.Planning Model – Long-term Reliability/Evaluation

– Joint effort between Reclamation and TROA Implementation

Office (Water Master’s Office) – for the Operations Model

– Stakeholders Input

Model Includes: • Supply (Inflows)

• Demand (water rights, etc.)

• Operating Criteria

– Pre-TROA: Based on 1935 Truckee River Agreement (TRA)

– Current: Truckee River Operating Agreement (TROA) 13 1/19/2016

Operation Criteria

• General Electric Decree (1915)

• Truckee River Agreement (1935)

• Orr Ditch Decree (1944)

• Donner Lake Agreement (1943)

• Tahoe-Prosser Exchange (1959)

• Interim Storage Agreement (1994)

• Adjusted OCAP – Operating Criteria and Procedure

(1997)

14 1/19/2016

Truckee River Operating Agreement:

TROA

• New Operating Policy: TROA

– Negotiated pursuant to PL 101-618 (1990)

– Partially implemented on December 1, 2015

– Full implementation – coming soon

• TROA Builds on current Truckee River

Agreement policy

– Adds operational flexibility

• Users may hold back their water as “credit water”

• Allows for system of exchanges between reservoirs

15 1/19/2016

Prosser Reservoir

Reservoir Characteristics

• Storage capacity

• Max Min Pools

• Outlet works

• Spillway capacity

• Storage Priority

• Flood Control Operations

• Evaporation

• Precipitation

• Power

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Operations Model

(15 months)

Operations Model

(15 months)

Planning Model

(100 year)

RiverWare Model Development

Pre-TROA TROA

Planning Model

(100 year)

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Ops Model for Water Management

Operation – Day-to-day Operations and Look Ahead

– Short-term Model – 15 months hydrology

– Operational forecasts for stakeholders since 2004

– Inflow – Current Gage and Forecasted

Model Use:

– Water Master – Daily operations and TROA Scheduling Committee

– Reclamation - Truckee Canal Diversion operations & Lahontan Flood operations

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RiverWare Framework

• Node-based river system operations model

• Physical characteristics

• Uses rule-based simulation - policy is coded in the

rule set

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RiverWare Operations Model - Forecasted

Inflow Methodology • NRCS/RFC April-July runoff volume

forecasts for 3 basins:

- Tahoe, Truckee, and Carson.

• Forecasts are given as probability of

exceedance:

- 10%, 30%, 50%, 70%, and 90%

• Obtain inflow hydrograph patterns -

volumes are matched to historically

similar years

• Disaggregate hydrographs to several

basin locations

• Model is run for each exceedance value

Lake Tahoe

Gage

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LBAO Forecasting What forecasts we produce and why

• OCAP Forecasts

Truckee Canal Operations

– Lahontan Monthly Target Storages • Ft. Churchill Apr-Jul Volume

• Carson Division Annual Demand

– Truckee Canal Monthly Diversions • Truckee and Carson Division Monthly Demand

• Truckee Canal Monthly Losses

• Lahontan Reservoir Monthly Losses

21 1/19/2016

• Forecasts Truckee Basin Operations

– Reservoir Filling/Flood Control Operations

– Reservoir Operations to meet Floriston Rates

– Tahoe-Prosser Exchange

– Truckee Meadows Diversions and Demands

– Fish and Wildlife Service Fish Releases

– Truckee Canal Operations

– Pyramid Lake Elevations

• TROA Operational Forecasting Using RiverWare – TROA Administrator – Parties to submit a schedule - coordination process

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LBAO Forecasting What forecasts we produce and why

WY 2016 January 14 Forecast - Hydrograph

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Farad AJ Vol

(KAF)

Carson AJ Vol

(KAF)

Tahoe Gate

Closed Rise (ft)

20% (W) 346 263 2.2

50% (M) 245 175 1.1

80% (D) 128 94 0.4

Average & Forecasted Farad Flow

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Observed and Forecasted Reservoir Storage

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WY 2016 Storage Preliminary Projection -

Tahoe

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WY 2016 Storage Preliminary Projection -

Stampede

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WY 2016 Storage Preliminary Projection -

Lahontan

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End!

Comments? Questions?

Truckee River Agreement-1935 The TRA is the basis for pre-TROA operation of Lake Tahoe, Boca Reservoir,

and the Truckee River.

A slightly modified version of the original Floriston Rates Agreement was

subsequently incorporated into the Truckee River Agreement. This included

Reduced Floriston Rates.

Lake Tahoe Elevations Oct. Nov.-Feb. March Apr.-Sept.

Less than 6225.25 feet 400 300 300 500

6225.25 to 6226.00 feet 400 350 350 500

Over 6226.00 feet 400 400 500 500

Parties to the TRA include:

TCID, SPPC (TMWA), and WCWCD

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WY 2015 Projection – Lake Tahoe Release

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0

3

7

10

13

16

20

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Ja

n-1

5

Fe

b-1

5

Ma

r-15

Ap

r-1

5

Ma

y-1

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Ju

n-1

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Ju

l-15

Aug-1

5

Sep-1

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Oct-

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c-1

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an

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nth

ly R

ela

ese

(C

FS

)

Re

lea

se

(kA

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Lake Tahoe--Release

30% Outflow 50% Outflow 70% Outflow

Combined Forecast

3/17/2015

WY 2015 Projection – Farad Gage Flow

1/19/2016 32

0

100

200

300

400

500

600

700

800 Ja

n-1

5

Fe

b-1

5

Mar-

15

Apr-

15

Ma

y-1

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Ju

n-1

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l-15

Au

g-1

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Se

p-1

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Oct-

15

No

v-1

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c-1

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Mo

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ly F

low

(cfs

)

Truckee River at Farad--Gage Flow

30% Flow

50% Flow

70% Flow

Floriston Rate_50%

"Floriston Rates_70%

"Floriston Rates_30%

Combined Forecast

3/17/2015

WY 2015 Projection – Nixon Gage Flow

1/19/2016 33

0

50

100

150

200

250

300

350

Ja

n-1

5

Fe

b-1

5

Ma

r-15

Apr-

15

Ma

y-1

5

Ju

n-1

5

Ju

l-15

Aug-1

5

Sep-1

5

Oct-

15

No

v-1

5

De

c-1

5

Me

an

Mo

nth

ly F

low

(cfs

)

Truckee River at Nixon--Gage Flow

30% Flow

50% Flow

70% Flow

Combined Forecast

3/17/2015

WY 2012-present Nixon Gage Flow

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WY 2015 Project – Prosser Storage

1/19/2016 35

4

5

6

7

8

9

10

11

12

13

14 Ja

n-1

5

Fe

b-1

5

Ma

r-15

Apr-

15

Ma

y-1

5

Ju

n-1

5

Ju

l-15

Aug-1

5

Sep-1

5

Oct-

15

No

v-1

5

Dec-1

5

Sto

rag

e (

kA

F)

Prosser Reservoir--Storage

30% Storage

50% Storage

70% Storage

Combined Forecast

3/17/2015

Truckee River Basin

Reservoirs

Reservoir Construction Date Use Storage Volume (AF)

Lake Tahoe 1874 / 1913 Floriston Rates 744,600

Independence Pre 1900 / 1939 POSW 3,000 / 17,500

Donner 1928 POSW 9,500

Boca 1938 Rates / FC / CS 40,870

Prosser 1963 TPX / Fish / FC 29,840

Stampede 1969 Fish / FC / CS 226,500

Martis 1971 Flood Control 20,400

1/19/2016 36

Lake Tahoe Facts

Maximum Elevation: 6229.10 feet

Elevation of Natural Rim: 6223.00 feet

Vertical Storage: 6.10 feet

Storage Capacity: 744,600 acre feet

Total Capacity: 122,160,000 acre feet

Historical Max. Elevation: 6231.26 feet (July 1907)

Historical Min. Elevation: 6220.26 feet (Nov. 1992)

1/19/2016 37

Average Annual Precipitation (Tahoe City): 32.33 inches

Average Annual Evaporation: +/- 3.8 feet (460,000 AF)

“Normal Year” Release: +/- 9.5 inches (95,000 AF)

Tahoe’s annual surface evaporation is enough water to meet the Reno-

Sparks area surface water demands for over five years!

Surface Area: 85,000 acres in CA + 37,000 acres in NV = 122,000 acres

Lake Tahoe Facts

1/19/2016 38

RiverWare Development Process

• Began in 2000

– Joint effort between Reclamation and TROA

Implementation Office (Water Master’s Office)

• 2009: Shift in Responsibility

– TROA Implementation Office in lead role for Ops model

– Reclamation support Ops model; lead planning

modeling

• 2010: Planning Model Development, Water

Quality Modeling

1/19/2016 39