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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
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
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
