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
ACWA Comment Letter on Notification Levels for PFOA and PFOS

Agency: State Water Resources Control Board, Division of Drinking Water Subject: Notification Levels and Response Levels for perfluorooctanoic acid (PFOA) […]

July 2019 Federal Regulatory Issues Chart

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

ACWA and CMUA Comment Letter on the Drinking Water Needs Assessment Conceptual Plan

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

ACWA Dues Automation Process Webinar

ACWA has a recording available of the webinar on the new Dues Automation Process. The purpose of this recording is to assist […]

ACWA 2019 Spring Conference Presentations

Presentations from ACWA’s 2019 Spring Conference & Exhibition held May 7-10 in Monterey are available below. Please note that this […]

Priority Issues Bulletin

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

Comment Letter on the Proposed Framework for Performance Standards for Water Loss

Agency: State Water Resources Control Board Subject: Proposed Framework for Performance Standards for Water Loss Letter excerpt:  Dear Mr. Gomberg: Thank […]

Federal Legislative Matrix

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

Overview Presentations: Water Conservation/Water Use Efficiency Laws of 2018 (AB 1668/SB 606) and Implementation Challenges

State Overview by Peter Brostrom, Department of Water Resources (May 2019) Implementations Challenges by David Bolland, ACWA (May 2019) A […]

May 2019 Federal Regulatory Issues Chart

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

COMMENT LETTER: U.S. Environmental Protection Agency and the U.S. Army Corps of Engineers Proposed Revised Definition of “Waters of the United States”

Agency: U.S. Environmental Protection Agency and the U.S. Army Corps of Engineers Subject: U.S. Environmental Protection Agency and the U.S. […]

California H2O: Flowing for the Future

ACWA and J Comm, Inc. have collaborated to create a 10-part video series to educate Californians about critical water issues. […]

Energy and Water Resources Policy Principles

In January 2019, ACWA released policy principles on “Energy and Water Resources” in California. The updated principles will help guide […]

ACWA’s 2019 Spring Legal Briefing and CLE Workshop Materials

The following presentations and materials for ACWA’s 2019 Legal Briefing and CLE Workshop on May. 7 from 9 a.m. to […]

ACWA Suggested Guidelines for 2019 Triennial Reporting of Public Health Goal Exceedance in Drinking Water

Agency: Public Water Systems and State Water Resources Control Board Division of Drinking Water Subject: Suggested Guidelines for Preparation of Required […]

Suggested News

15 Articles prev next
CVWD increases rebates for two landscape programs

Coachella Valley Water District (CVWD) is offering increased rebate incentives for two landscape programs benefitting homeowner associations and commercial customers. […]

Water Quality Issues in Focus at 2019 ACWA Regulatory Summit

ACWA will host its ninth annual Regulatory Summit on Oct. 17 at the Hilton Sacramento Arden West, where attendees will […]

District recognized as Chamber ‘Member of the Year’ for Sewer System Funding Efforts

YUCCA VALLEY – Hi-Desert Water District (HDWD) was named Member of the Year by the Yucca Valley Chamber of Commerce […]

SCV Water Moves Forward with Testing Water Treatment to Remove PFAS

The SCV Water Board of Directors approved expedited testing of treatment options for per- and polyfluoroalkyl substances (PFAS), which were […]

SWEETWATER AUTHORITY AWARDS GRANTS TO SUPPORT WATER EFFICIENCY IN SOUTH BAY

CHULA VISTA – The Sweetwater Authority (Authority) Board of Directors presented checks to the City of Chula Vista and the […]

July 2019 Priority Issues Update

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

General Manager Steve Nugent of Carmichael Water District Retires

With over 37 years in the water industry, Carmichael Water District (CWD) General Manager, Steve Nugent, announced his retirement on […]

ACWA Accepting Applications and Nominations for Fall Awards

ACWA will present several awards at its 2019 Fall Conference & Exhibition in San Diego, being held Dec. 3-6, and […]

ACWA Supports Legislature’s Approval of Safe Drinking Water Funding Solution

SACRAMENTO – The Senate July 8 approved SB 200 (Monning), putting California one step closer to enacting the second part […]

South Coast Water District Certifies EIR for Ocean Desalination Project

On June 27, the South Coast Water District (SCWD) Board of Directors certified the Final Environmental Impact Report (EIR) for […]

Annual Water Quality Report: Western’s Water is Clean and Safe to Drink

RIVERSIDE – The annual report card on Western Municipal Water District’s water quality is in and the results reflect, as […]

Walnut Valley Water District Details Strategic Vision for the Future

WALNUT – The Walnut Valley Water District (WVWD) Board of Directors has formally adopted a strategic plan for 2019, which […]

New Website Offers RWD Customers Improved User Experience

ROWLAND HEIGHTS – Rowland Water District launched a brand new website featuring enhanced content, more intuitive navigation and a suite […]

AAA-Rated Moulton Niguel Approves On-Time, Balanced Budget

Moulton Niguel Water District, which holds a coveted AAA credit rating from two independent credit ratings agencies, has approved an […]

ACWA Comments on California Fiscal Year 2019-’20 Budget

SACRAMENTO – ACWA Executive Director Dave Eggerton issued the following statement in response to Gov. Gavin Newsom’s signing of the […]