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Real-time Ensemble Hydrological Forecasts for a 2017 Mock

Operation Test of Forecast Informed Reservoir Operations of

Lake Mendocino in Mendocino County, California

Chris Delaney

John Mendoza

Brett Whitin

Robert Hartman

August 8, 2018

Presentation Overview

• Background

• Ensemble Forecast Operations (EFO) Model

– Model Description

– How it works

• 2017 Model Results

• Next Steps

Forecast Informed Reservoir Operations

Lake Mendocino FIRO Demonstration Project

Steering Committee

County, State and Federal Agencies

Co-Chairs: Jay Jasperse, Sonoma Water

Marty Ralph, Center for Western Weather Water Extremes (CW3E)

Preliminary Viability Assessment – Summer 2017

Objective

Improve water supply reliability, yet

Not increase flood risk to downstream communities.

Sonoma Water

Lake Mendocino

Upper Russian River Watershed

Coyote Valley Dam Constructed by the Army Corps of

Engineers in 1959

USACE: Flood Control

Sonoma Water: Water Supply

Watershed Area: 105 mi2

Potter Valley Project – PG&E Imports water from the Eel River to the

East Fork Russian River

2006 FERC License Amendment

56% reduction in imports

Max Water Supply: 111,000 acre-feet

Lake Mendocino Guide Curve

Reduced supply capacity

during wet season

Expanded supply

capacity during dry season

Lake Mendocino Guide Curve

WY2012 ≈ WY2013

Distribution very different

Different storage

outcomes

Can we save some

of this water?

7

2017 Wettest Year on Record for the

Russian River

8

Reservoir Management Model Developed in MatLab

Hourly and Daily Time Step

Upper Russian River Potter Valley Project to the USGS Gage

at Healdsburg

70 mile reach

6 Model Junctions

USGS Discharge Gages

CNRFC Forecast Points

Lake Mendocino

Ensemble Forecast Operations Model

Hydrology 1. 2017 Virtual Operations Trial

Real-time CNRFC Ensemble Flow Forecast

o 59 –member, 15-day

2. Historical Conditions: 1985-2010

CNRFC Ensemble Flow Hindcast

Support Preliminary Viability Assessment

Flood Operations Scenarios 1. Current Operations – Observed Conditions

2. Ensemble Forecast Operations (EFO) – Risk Based

California Nevada

River Forecast Center

CNRFC

Hydrologic Ensemble

Forecast System

HEFS

Lake Mendocino Ensemble Forecast Operations Model

Ensemble Forecast Operations (EFO)

CA NV River Forecast Center

Ensemble Flow Forecast Storage Forecast

Flood Risk Analysis

Flood Release

Process repeated each day

2017 Virtual Operations Test

Small events in December

Filling reservoir

Corps flood release

EFO scenario storing water

January 3rd Forecast

January 3rd Forecast

111,000 acre-feet

Max Conservation Level

January 3rd Forecast

Risk based guide curve

January 3rd Forecast

EFO Flood Release = 2,000 cfs

2017 Virtual Operations Test

2,000 cfs pre-release

for 5-days

Reduced storage before

storm event

2017 Virtual Operations Test

Flood control operations:

High inflows & Reduced releases

Rapid increase

In storage

No increase in peak flows

2017 Virtual Operations Test

Pre-release in advance of storm

2017 Virtual Operations Test

Flood operations = reservoir refill

2017 Virtual Operations Test

EFO scenario reduced

lower than Observed

EFO peak ≈ Observed Peak

2017 Virtual Operations Test

EFO scenario storing water

5,500 af

1985-2010 Historical Simulation

Lake Mendocino Storage

1985-2010 Historical Simulation

Hopland Flows

No increase in flow

above flood stage

Flood Stage

Nuisance Flooding

2019 Major Deviation

• Major Deviation submitted to USACE in January 2018

– Currently under review by USACE

• Hybrid alternative - EFO and guide curve

– Modified guide curve = 10% increase in winter months

Limited EFO

Final Viability Assessment • Final Viability Assessment (FVA) will be a multi-

disciplinary study: • Meteorology

• Hydrology

• Hydraulics

• Reservoir operations

• FVA will support modification to Water Control Manual

• Further evaluation and refinement of EFO model will

be a component in the FVA

– Extend EFO model downstream to Guerneville

– Develop hydrology to test EFO for extremes events

• 200-year and possibly 500-year events

– Refine risk curve

• Optimization of flood control and water supply benefits

Questions?

Contact:

E-mail:

Contributors:

Chris Delaney

chris.delaney@scwa.ca.gov

John Mendoza, Brett Whitin, Robert Hartman

?

Supplemental Slides

1985-2010 Historical Simulation

End of Water Year Storage

~20K acre-feet increase in median

EFO Modeling Process

Risk > Tolerance

EFO Modeling Process

Ensemble members to

evaluate release schedules

EFO Modeling Process

Day 1 Release = 891 cfs

Controlling

ensemble member

EFO Modeling Process

Time Step Release (cfs)

1 0

2 0

3 0

4 0

5 0

6 0

7 28

8 891

9 1442

10 1858

11 1905

12 1936

13 1892

14 1838

15 1776

12 1936

Max Day 1

Releases

Risk ≤ Tolerance

Forecast Window Sensitivity

Forecast Window Sensitivity

sonomawater.ca.gov

Chris Delaney

Engineer

Chris.delaney@scwa.ca.gov