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sonomawater.ca.gov
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
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Presentation Overview
• Background
• Ensemble Forecast Operations (EFO) Model
– Model Description
– How it works
• 2017 Model Results
• Next Steps
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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
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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
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Lake Mendocino Guide Curve
Reduced supply capacity
during wet season
Expanded supply
capacity during dry season
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Lake Mendocino Guide Curve
WY2012 ≈ WY2013
Distribution very different
Different storage
outcomes
Can we save some
of this water?
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2017 Wettest Year on Record for the
Russian River
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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
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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
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Ensemble Forecast Operations (EFO)
CA NV River Forecast Center
Ensemble Flow Forecast Storage Forecast
Flood Risk Analysis
Flood Release
Process repeated each day
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2017 Virtual Operations Test
Small events in December
Filling reservoir
Corps flood release
EFO scenario storing water
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January 3rd Forecast
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January 3rd Forecast
111,000 acre-feet
Max Conservation Level
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January 3rd Forecast
Risk based guide curve
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January 3rd Forecast
EFO Flood Release = 2,000 cfs
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2017 Virtual Operations Test
2,000 cfs pre-release
for 5-days
Reduced storage before
storm event
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2017 Virtual Operations Test
Flood control operations:
High inflows & Reduced releases
Rapid increase
In storage
No increase in peak flows
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2017 Virtual Operations Test
Pre-release in advance of storm
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2017 Virtual Operations Test
Flood operations = reservoir refill
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2017 Virtual Operations Test
EFO scenario reduced
lower than Observed
EFO peak ≈ Observed Peak
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2017 Virtual Operations Test
EFO scenario storing water
5,500 af
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1985-2010 Historical Simulation
Lake Mendocino Storage
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1985-2010 Historical Simulation
Hopland Flows
No increase in flow
above flood stage
Flood Stage
Nuisance Flooding
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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
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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
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Questions?
Contact:
E-mail:
Contributors:
Chris Delaney
[email protected]
John Mendoza, Brett Whitin, Robert Hartman
?
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Supplemental Slides
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1985-2010 Historical Simulation
End of Water Year Storage
~20K acre-feet increase in median
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EFO Modeling Process
Risk > Tolerance
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EFO Modeling Process
Ensemble members to
evaluate release schedules
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EFO Modeling Process
Day 1 Release = 891 cfs
Controlling
ensemble member
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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
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Forecast Window Sensitivity
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Forecast Window Sensitivity
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sonomawater.ca.gov
Chris Delaney
Engineer
[email protected]