Forecast-Informed Reservoir Operations: A Concept Supporting Water Supply and Flood Control

Developed by the

Center for Western Weather and Water Extremes – “CW3E”

at UC San Diego/Scripps Institution of Oceanography

Dr. F. Martin Ralph (mralph@ucsd.edu)

6 May 2014; UCDC Water Research Briefing; Washington, DC

16 inches of rain in 1 day in Central California

The Challenge

Figure from an article in Scientific American

by Dettinger and Ingram (January 2013)

A Major Result from 10-years of Research

Atmospheric rivers – what they are, how they work, and their

crucial role in both water supply and flooding across much of the

U.S. West Coast

Atmospheric Rivers, Floods and the Water Resources of California by Mike Dettinger, Marty Ralph, , Tapash Das, Paul Neiman, Dan Cayan

Water, 2011

25-35% of annual precipitation in the

Pacific Northwest fell in association with

atmospheric river events

35-45% of annual precipitation in California fell in association with

atmospheric river events

An average AR transports the

equivalent of 7.5 times the average discharge of the

Mississippi River, or ~10 M acre feet/day

ARkStorm: An emergency preparedness scenario for California

USGS organized a large team of experts.

A meteorology team was formed and built a plausible physical scenario. Back-to-back extreme AR events (mostly based on actual 1969 and 1986 storms) struck over about 3 weeks . Considers the 1861/82 floods as an example. The meteorological scenario was then given to follow-on groups of experts in damage assessment and economic disruption estimation and has become the basis for emergency preparedness exercises.

Dettinger et al. 2011 (Natural Hazards)

Projected damage and economic losses exceed

$500 Billion

Atmospheric Rivers Contribute to Annual

Precipitation in Northern California’s Key Region

Providing much of the State’s Water Supply

One major AR event in Dec 2012 over 3-5 days provided about 1/3 of the entire Water Year’s precipitation (i.e., 15 inches out of 46 inches)

Water year 2012 precipitation total was 46.2 inches

• Flood Preparedness

and Response

• Flood Planning

• Reservoir Coordinated

Operations

• Water Supply Forecasting

California’s Department of Water

Resources (DWR)

Program Applications of

Atmospheric Rivers Network Data

Courtesy of Mike Anderson

- CA Dept. Water Resources

- CA State climatologist

Concept

Demonstrate that better monitoring and prediction of atmospheric river storms

can enable increased water storage while maintaining flood control capabilities

Strategies

Develop, deploy and demonstrate new atmospheric-river-focused monitoring

and prediction methods targeting extreme events and their roles in flooding and

drought. This is done by advancing the science, observing systems, forecast

models, decision support tools and communication methods.

Atmospheric Rivers – A UCSD/CW3E Vision Supporting California Water Management

Expertise and Partnerships Needed: University, Local, State, Federal.

A Path Toward Solutions

21st Century

Observations

21st Century

Modeling

Science

Decision Support Tools + Forecast-Informed Reservoir Operations

There is no “Silver bullet” for this complex problem.

F.M. Ralph

Scripps/CW3E

BENEFITS: Water Supply, Flood

Control

Ecosystems, Hydropower, etc…

Atmospheric Rivers – A UCSD/CW3E Vision Supporting California Water Management

There is no “silver bullet” Requires an Integrated,

Multi-disciplinary Strategy

Conceptual Observation Network and Forecast Lead Time for Atmospheric Rivers

Recurving West Pacific Tropicals 5-7 days

Amplifying Jet Stream - RWD

G-IV

Profilers MJO 7-10 days

Ensemble MJO Fcst

Frontal wave stalls AR over CA - AROs

Tropical Tap?

UAVs

Landfall Recommendation from an interagency team presented in Ralph et al., 2014

11

California has begun implementation of key

land-based sensors

An Atmospheric River-focused long-term observing network is being installed in CA as part of a 5-year project between CA Dept. of Water Resources (DWR), NOAA and Scripps Inst. Of Oceanography - Installed 2008-2014 - >100 field sites

CalWater-2* “Early Start” field campaign 3-25 February 2014

Summary Courtesy of Marty Ralph UCSD/Scripps/Center for Western Weather and Water Extremes

Up to > 12 inches of rain – some drought relief

This AR increased precipitation-to-date from 16% to 40% of normal in <

4 days in key Northern California watersheds, but runoff was muted

due to dry soils.

*CalWater-2 is a 5-year program (from 2015-2019) proposed to focus on West Coast precipitation processes and how a changing climate will affect them. It is led by UCSD/Scripps with partners from DWR, CEC, NOAA, NASA, DOE and others. SSM/I satellite observations of water vapor on 8 Feb 2014 (Courtesy G. Wick, NOAA)

Russian River’s highest flow in > 1 year

Flight area for NOAA’s G-IV aircraft on 8 Feb 2014

Goal: developing AR flight method to sample a “frontal wave” that can cause an AR to stall

over one area at landfall (G-IV PI: Chris Fairall – NOAA; Mission Scientists: Marty Ralph –

Scripps, Ryan Spackman – STC)

Hawaii

NOAA HMT Network

Wind Profilers, Radars, GPS Met Sierra Nevada and Coastal Ranges (white bars)

Hawaii SSM/I satellite observations of IWV showing a strong atmospheric river on 12 Dec 2010 (from Ralph and Dettinger BAMS 2012)

CalWater 2 / ACAPEX Observational Strategy

Jan – Mar 2015

Remote aerosol plume

(schematic)

20°N

30°N

40°N

50°N

160°W 150°W 140°W 130°W

50N

40N

30N

20N

160W 150W 140W 130W

7654321

IWV (g cm-2

)

40N

30N

20N

160W 150W 140W 130W 120W

12 December 2010

18 December 2010

NOAA WP-3D - Aerosols & Trace Gas Instruments

- Cloud Probes

- Dropsondes

- Precipitation & Cloud Radar

NASA Global Hawk & NOAA G-IV - Dropsondes - Precipitation & Cloud Radar

Courtesy of F. M. Ralph, NOAA Earth System Research Laboratory

DOE G-1

- Aerosols - Microphysics

Ship

- DOE AMF2 - Small UAS - Air-sea fluxes - Precipitation estimates

Scripps Institution of Oceanography

NASA JPL

Science and Technology Corporation

NOAA Earth System Research Laboratory

Water vapor budget of ARs offshore and their impacts on

landfall

- NASA Global Hawk (3 winters)

- NASA DC-8 (2 winters)

EFREP AR Obs network onshore

Marty Ralph (PI)

Duane Waliser (Deputy PI), Ryan Spackman (Deputy PI)

Atmospheric River Experiment – AREX Proposal to NASA’s EV AO

1895-2010

Dettinger, Michael D., 2013: Atmospheric Rivers as Drought Busters on the U.S. West Coast. J. Hydrometeor, 14, 1721–1732.

Droughts, on average, end with a bang (and begin with a whimper) all over the U.S.

• Atmospheric rivers provide the bang in a large fraction of the west coast drought breaks, especially in winters

Mission Provide 21st Century water cycle science, technology and outreach to support effective policies and

practices that address the impacts of extreme weather and water events on the environment, people and

the economy of Western North America

Goal Revolutionize the physical understanding, observations, weather predictions and climate projections of

extreme events in Western North America, including atmospheric rivers and the North American summer

monsoon as well as their impacts on floods, droughts, hydropower, ecosystems and the economy

Atmospheric

Rivers

(fall and winter)

Southwest

Monsoon

(summer & fall)

Great Plains Deep

Convection

(spring and summer)

Spring Front Range

Upslope

(rain/snow)

Center for Western Weather and Water Extremes Where: UCSD/Scripps Inst. Oceanography La Jolla, California When: Start - 2013 Who: Dr. F. M. Ralph (Director) Dr. Dan Cayan Dr. Mike Dettinger Dr. Ryan Spackman

Scripps Institution of Oceanography

The Challenge

Using modern science and engineering, and a collaborative approach to developing a small scale demonstration, the answer is likely YES

A NEXT STEP IS UNDERWAY: A planning team has been formed to develop a detailed roadmap forward, including relevant local, state and federal entities, brought together by UCSD/Scripps/Center for Western Weather and Water Extremes. Information needs will be defined, potential solutions developed, to be carried out as a demonstration on Lake Mendocino in northern California.

Region for which atmospheric river events are a dominant cause of extreme precipitation, flooding and contribute to water supply in the Western U.S. (Ralph et al. 2014)

18

Region of major atmospheric river influence

Lake Mendocino - Pilot study

Contact: F. Martin Ralph (mralph@ucsd.edu) Website: http://woodland.ucsd.edu/