MEMBER SPOTLIGHT – February 2019

  • by Will Holbert
  • Feb 22, 2019
  • Newsletters

Promise and Progress With Predicting Atmospheric Rivers

This NASA Earth Observatory photo shows an atmospheric river hitting California. Advances in research and weather modeling have the potential to change how reservoirs are currently managed to maximize water storage going into the dry months. Photo courtesy of the Scripps Institution of Oceanography, University of California San Diego.

In California water, 2019 is shaping up to be the year of the atmospheric river, but not just because several have soaked the state and blanketed the Sierras. A transformation now underway combines progress in forecasting ability with a willingness to re-examine how we manage reservoirs.

This transformation is called Forecast Informed Reservoir Operations, or FIRO.  It recently took one of its first steps from working in theory to proving with results. 

At Lake Mendocino, Sonoma Water and the Army Corps of Engineers agreed to deviate from standard practice that required excess water to be released to maintain reservoir space for flood control. When an atmospheric storm rolled over the Russian River watershed in mid-January, this flexibility allowed dam operators to retain an extra 6,000 acre-feet of water. Instead of a set schedule, forecasting that can provide a 15-day weather outlook will decide if that water stays in Lake Mendocino as long as possible to maximize storage capacity for summer.

Five ACWA member agencies envision a day in the near future when the FIRO experiment at Lake Mendocino can be standard practice throughout the state, one that could increase water storage while providing improved flood control and disaster preparedness. 

“The FIRO demonstration project is so exciting because it can increase our water supply at a much lower cost than other alternatives,” said ACWA Vice President Steven LaMar. “Based upon the research being done at Lake Mendocino, the same approaches can be pursued at many other reservoirs throughout California and beyond. The additionally stored water can provide benefits to both water users and environmental needs, including endangered fish migrations.”

The five-member FIRO coalition includes Sonoma Water, Yuba Water Agency, Turlock Irrigation District, Orange County Water District and the San Diego County Water Authority. In addition to the Army Corps, the Scripps Institution of Oceanography’s Center for Western Water and Weather Extremes (CW3E) is working with the water districts as part of its larger and long-term research into atmospheric rivers, which members of the scientific and water community have shortened to “ARs.” The state Department of Water Resources is also playing a key role in supporting research, along with the National Oceanic and Atmospheric Administration and the U.S. Fish and Wildlife Service.

The coalition recently sent a letter to DWR’s Strategic Water Planning Branch, writing in support of a Draft Water Plan Update calling for coordinated climate science and monitoring efforts. The efforts included advancing forecasting models and operations, identifing new ways to observe ARs, and supporting the development of tools to assess opportunities and risks, such as floods and post-wildfire debris flows, but also groundwater recharge following atmospheric river events. 

OCWD wants to utilize the FIRO concept to capture and keep of much as 20,000 additional acre-feet stormwater at its Prado Dam during a wet year, instead of releasing it into the Pacific Ocean. That could save district ratepayers $20 million annually by offsetting the cost of water currently purchased from Northern California and the Colorado River.

Stretching the ability to accurately forecast ARs ever farther into the future has its own name – S2S – for sub-seasonal to seasonal prediction. The big goal is improving forecasting beyond two weeks and possibly into months, said Jeanine Jones, DWR Interstate Resources Manager. And ultimately, it is about more than predicting weather events, but conditions leading to those weather events. That includes atmospheric ridges that can wall off California from ARs and lengthen droughts. Beyond better reservoir management, future success with S2S forecasting can also give water managers a critical edge in ramping up conservation efforts before the hot season, or taking advantage of extra time for flood preparedness.

The challenges are many, but at least one of them boils down to access to existing technology.

“Improving S2S forecasting requires use of high resolution models, which requires more supercomputing access than we have now,” Jones said. 

Lake Mendocino, where the concept of Forecast Informed Reservoir Operations – FIRO – proved itself through a demonstration in January. The demonstration allowed the total storage of more than 68,400 acre-feet for the first time since the reservoir’s creation in 1958. Photo courtesy of Sonoma Water.

Some recent progress includes changing our perspective of ARs, by measuring them and recognizing the critical role they represent in California water. Up to half of California’s total annual precipitation and 90% of its flooding are caused by sporadic, extreme AR rain events. An entire water year, and the risk of flooding and drought, may hinge on a few AR storms. 

At Scripps, CW3E Director Marty Ralph and several other weather experts developed a scale that ranks atmospheric rivers on a range from one (weak) through five (exceptional), similar to how hurricanes are categorized. Announced in early February, the CW3E scale goes beyond the functionality of the hurricane scale system by incorporating duration and indicating the balance between beneficial results and potential for flood hazards. 

“We’re on the verge of a historic transformation in understanding how atmospheric rivers can achieve multiple goals in water system operations, including drought relief, groundwater recharge and fisheries health,” said ACWA Executive Director Dave Eggerton. “This newest tool illustrates how we can better prepare for flood events, and maximize opportunities for extra storage.”

Suggested Resources

15 RESOURCES prev next
Comment Letter: Proposed Decision Adopting Additional and Modified De-Energization Guidelines

Agency: California Public Utilities Commission Subject: Joint Comments of Valley Center Municipal Water District, Padre Dam Municipal Water District, Municipal Water […]

Comment Letter: White Paper Discussion on Economic Feasibility Analysis in Consideration of a Hexavalent Chromium MCL

To: Jeanine Townsend, Clerk to the Board State Water Resources Control Board Subject: White Paper Discussion on Economic Feasibility Analysis […]

ACWA Submits Letters Urging State and Federal Leadership to Achieve Voluntary Agreements

To: Governor Newsom and U.S. Department of Interior Secretary Bernhardt Subject: Voluntary Agreements Description: ACWA urges Gov. Newsom and Secretary […]

Coalition Letter: Funding for Water Infrastructure & Affordability in Response to COVID-19 Pandemic

To: Speaker Pelosi, Minority Leader McCarthy and Members of the California Congressional Delegation: Subject: Include Urgently Needed Funding for Water […]

Webinar: How to Reduce Costs with PG&E’s New Time-of-Use (TOU) Rate Analysis

Sorry, but only ACWA members have permission to view this content. Member login is required.

Comment Letter: Draft Handbook for Water Budget Development

Agency: California Department of Water Resources Subject: Comment Letter on the ‘Draft Handbook for Water Budget Development: With or Without […]

Federal Regulatory Issues Chart

Sorry, but only ACWA members have permission to view this content. Member login is required.

2019 Year in Review

Throughout 2019, ACWA advanced its policy goals by employing robust advocacy at the state and federal levels. Collaborative work with member […]

Comment Letter: REMAT Proposed Decision

Agency: California Public Utilities Commission Subject: Comments of REMAT Parties on Proposed Decision Adopting New Standard Offer Contract for Qualifying […]

Webinar: COVID-19 Series – Virtual Water Agency Board Meetings During COVID-19

Sorry, but only ACWA members have permission to view this content. Member login is required.

Comment Letter: Proposed Definition of “Microplastics in Drinking Water”

Agency: State Water Resources Control Board Subject: ACWA’s Comments regarding Proposed Definition of “Microplastics in Drinking Water” Letter excerpt: The […]

Comment Letter: ACWA Request for COVID-19 Federal Relief Funding

To: Leader McConnell, Speaker Pelosi, Leader Schumer, and Leader McCarthy Subject: ACWA Request for COVID-19 Federal Relief Funding Letter excerpt: The […]

Webinar: COVID-19 Series – Understanding the Financial Aspects

Sorry, but only ACWA members have permission to view this content. Member login is required.

Comment Letter: Request Tax Credit for State and Local Governments in HR 6201

To: Leader McConnell, Speaker Pelosi, Leader Schumer, and Leader McCarthy Subject: ACWA Request to Correct Tax Credit for State and Local […]

Webinar: COVID-19 Series – Operational Challenges

Sorry, but only ACWA members have permission to view this content. Member login is required.

Suggested News

15 Articles prev next
Now in Effect: State Wetland Definition and Procedures for Discharging

As of May 28, the State Wetland Definition and Procedures for the Discharges of Dredged or Fill Material to Waters […]

East County Advanced Water Purification Program moves forward with key service agreement approvals

SANTEE – The East County Advanced Water Purification (AWP) Joint Powers Authority (JPA) Board of Directors and all partnering agencies […]

Regional collaboration on water purification project expands local, drought-proof supply of drinking water

The Helix Water District Board of Directors authorized its General Manager to sign water purchase agreements for the East County […]

Facilities with long-term closures encouraged to flush water pipes prior to reopening

RIVERSIDE – Western Municipal Water District (Western) is encouraging businesses, schools and other buildings that have been closed to flush […]

UWPA Board Hires New General Manager

ANGELS CAMP – The Utica Water and Power Authority (UWPA) Board of Directors is pleased to announce that Joel Metzger […]

AVEK receives $89,954 Refund for Maintaining a Safe Workplace

PALMDALE – A low number of worker’s compensation claims and minimizing liabilities earned the Antelope Valley-East Kern Water Agency (AVEK) a […]

Lieutenant Governor, State Water Leaders to Address 2020 Summer Virtual Conference Attendees

California Lt. Gov. Eleni Kounalakis, California Natural Resources Secretary Wade Crowfoot and Department of Water Resources Director Karla Nemeth will […]

i-Meter Update – Scotts Valley Water District

SCOTTS VALLEY — Scotts Valley Water District crews have upgraded approximately 85 percent of all water meters to new intelligent […]

Spotlight: ACWA Members Respond to Unprecedented Challenges Presented by COVID-19 – May 2020

The COVID-19 pandemic has presented unprecedented challenges to California water agencies and continues to leave the state’s essential water and […]

State Water Project Allocation Increases to 20%

SACRAMENTO – The State Water Project (SWP) now expects to deliver 20% of requested supplies in 2020 thanks to above-average precipitation […]

ACWA News Available for May 22, 2020

Sorry, but only ACWA members have permission to view this content. Member login is required.

Western Municipal Water District lands $200,000 federal grant for drought planning

RIVERSIDE – Western Municipal Water District (Western) received a $200,000 grant award from the United States Bureau of Reclamation for […]

OCWD Recognized for Excellence in Financial Reporting

FOUNTAIN VALLEY – The Government Finance Officers Association (GFOA) awarded a Certificate of Achievement in Excellence in Financial Reporting to […]

Riverside County’s Family of Water Agencies Reassures Customers Tap Water is Safe

Riverside County’s family of water agencies this past week launched a collaborative campaign with a goal to continue assuring customers […]

Rowland Water District Celebrates Essential Workers & Customers

ROWLAND HEIGHTS – As part of the observance for this year’s Special Districts Week, Rowland Water District is acknowledging essential […]