Chino Basin Watermaster - October 2023 Update

OCTOBER 2023 UPDATE

Chino Basin

Watermaster OCTOBER 2023 UPDATE

OCTOBER

2023

FEATURED ARTICLE: 2025 SAFE YIELD REEVALUATION

Welcome!

October 2023 Update As the colors of autumn leaves begin to show, we are delighted to bring you the premiere edition of the Chino Basin Watermaster Update. In this season of change, we invite you to join us on a journey through the intricacies of water management in the Chino Basin and to stay informed about the important work being done to ensure a sustainable future for our community.

At Chino Basin Watermaster, our mission is to manage and protect the precious water resources that sustain our region.

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believe that “ We informed stakeholders

are essential to the success of our mission...

This newsletter is your window into the heart of the Chino Basin Watermaster’s ongoing activities. We are committed to keeping all stakeholders informed and engaged in our ongoing efforts.

Whether you are a resident, a business owner, a member of a local agency, or simply someone who cares deeply about the future of our water resources, this newsletter is designed with you in mind.

Long Term Studies, Analyses, and Planning • Safe Yield Recalculation • Simulate the Effects of a ‘Run on Storage’ • Develop Water Quality Management Plan • Storage Management Plan Review

In the pages that follow, you’ll find updates on the progress of the ongoing activities, answers to frequently asked questions, and stories that celebrate our collective successes. We believe that informed stakeholders are essential to the success of our mission, and we are here to provide you with the information you need to have confidence in our plan and its implementation. We ask that you review the listed Long Term Studies, Analyses, and Planning as we will need your attention and engagement on them as we move forward. While each of these efforts may sound stand-alone, we encourage you to see them as related chapters of a larger program plan that builds our capacity to maximize the beneficial uses of the Chino Basin for all stakeholders.

• Study How the Groundwater Basin Can Be Used to Firm Up the Reliability of Local Supplies

Our commitment to transparency and accountability remains

• Develop Storage & Recovery Master Plan

to us, and we are here to ensure that your voice is heard.

unwavering, and we encourage you to reach out with any questions or concerns you may have. Your feedback is invaluable

Thank you for being a part of the Chino Basin Watermaster community. We look forward to sharing our journey with you and keeping you informed every step of the way.

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Featured Article

2025 Safe Yield Reevaluation On August 30, 2023,Watermaster conducted its first workshop for the 2025 SYR to discuss the proposed updates to the CVM (Task 1).

Garrett Rapp, PE Project Manager for 2025 SYR

BACKGROUND The Safe Yield of the Chino Basin is the long-term average annual quantity of groundwater that can be produced from the Basin without causing an undesirable result. Calculating the Safe Yield is necessary for Watermaster to fulfill much of its obligations.

The Judgment set the initial Safe Yield at 140,000 acre-feet per year (afy). The Safe Yield has been recalculated and reset twice since the original adjudication in 1978: once for the period of 2011 through 2020, and once for the period of 2021 through 2030. The current Safe Yield is 131,000 afy, which resulted from the 2020 Safe Yield Recalculation (2020 SYR).

The two Safe Yield recalculations were completed pursuant to a methodology developed in 2015 (2015 SYRM) and includes the use of the Chino Basin Watermaster’s

(Watermaster’s)

groundwater-flow model to calculate the projected annual net recharge in the Chino Basin. The 2015 Safe Yield Reset Methodology was approved by a Court order in April 2017 (2017 Court Order).

The 2017 Court Order included other stipulations such as (1) approving the reset of the Safe Yield for 2011 through 2020, (2) mandating that the Safe Yield be recalculated and reset for the period of 2021 through 2030, (3) allowing for the update of the 2015 SY Reset methodology, and (4) requiring that the groundwaterflow model (called the Chino Valley

SAFE YIELD: The long-term average annual quantity of groundwater that can be produced from the Basin without causing an undesirable result.

Model, or CVM) be updated and that the Safe Yield (for 2021 through 2030) be reevaluated by June 2025. This mandate for reevaluating the Safe Yield is known as the 2025 Safe Yield Reevaluation (2025 SYR).

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In 2021 and 2022, Watermaster developed

3. Develop projection realizations that

an updated Safe Yield reset methodology

include the range of future scenarios

with the advice and assistance from the

of hydrology and cultural conditions

parties and their technical consultants.

in the Chino Basin

This

methodology,

known

as

the

2022 SYRM, addressed many of the comments on the 2020 SYR and better accounts for the inherent uncertainty

4. Simulate projection realizations 5. Evaluate simulation results and calculate Safe Yield

in groundwater-flow model parameters,

6. Develop 2025 SYR report

future hydrology, and future cultural

7. Reset Safe Yield (if necessary)

conditions (e.g., groundwater pumping, land use, irrigation patterns). The 2022 SYRM was approved by the Court in December 2022 and must be used for the 2025 SYR. SCOPE OF THE 2025 SYR

If the results of Task 5 indicate that the Safe Yield for the period of 2021 through 2030 is different than the current Safe Yield by more than 2.5 percent, Watermaster will seek the advice and recommendation of the Pool and Advisory Committees

The 2025 SYR was initiated in spring 2023.

before making a recommendation to the

The scope of the 2025 SYR follows the

Court regarding potential changes to the

2022 SYRM and comprises the following

Safe Yield.

tasks: 1. Update the groundwater-flow model that was used in the 2020 Safe Yield Recalculation 2. Generate multiple calibrated realizations based on the updated model

The 2022 SYRM was approved by the Court in December 2022 and must be used for the 2025 SYR.

CURRENT SAFE YIELD

131,000 ACRE-FEET PER YEAR (AFY)

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Watermaster is soliciting input from the parties and stakeholders to aid in developing scenarios for the 2025 SYR. STATUS AS OF OCTOBER 2023 As of October 2023, Watermaster is completing Task 1 and has initiated Tasks 2 and 3. On August 30, 2023, Watermaster conducted its first workshop for the 2025 SYR to discuss the proposed updates to the CVM (Task 1). The proposed updates to the model include incorporating new information gathered from new wells that have been constructed since the development of the prior CVM. More detail can be found in the presentation materials from the August workshop here.

To support the development of the projection scenarios that will be used in the 2025 SYR, Watermaster is hosting a workshop for the parties and other stakeholders on October 24, 2023. The objectives of this workshop are to ensure parties’ collective understanding of the scenario design process and gather input from the parties and stakeholders on the drivers of changes in water demands and supply plans. Input from this workshop will inform the scenarios that will be developed for the 2025 SYR. FUTURE SCHEDULE The graphic shows the future meetings and workshops that will support the 2025 SYR, including the date and subject. You can also view the schedule here.

DID YOU KNOW: The 2000 OBMP Implementation Plan requires that the Safe Yield of the Chino Basin be recalculated every 10 years, beginning in 2011.

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Meeting and Workshop Schedule 2025 Safe Yield Reevaluation Pursuant to the April 28, 2017 Safe Yield Court Order

Audience:

Technical Peer Review Committee

General Stakeholders

COMPLETED Aug. 30, 2023 9:00am (virtual)

Hydrogeologic Conceptual Model

Review the structure of the 2020 CVM, discuss the updates made to the HCM based on information gathered since 2020 SYR, and gather feedback on changes.

• 2022 Safe Yield Reset Methodology TM • Agenda

Oct. 24, 2023 9:00am (in-person)

Scenario Design #1

Discuss the process to develop an ensemble of projection scenarios, gather input from the Parties on drivers of and uncertainties in future water demands and supply plans.

Includes discussion of potential extreme scenarios for effort to evaluate of future extremes.

February 2024

Scenario Design #2

Review draft TM describing proposed water demand and supply plan scenarios, discuss recommendations on climate scenarios to use in model ensemble, and gather feedback.

• Presentation

March 2024

Calibration #1

Present initial results on model calibration and recommended subset of calibration realizations. Gather feedback on recommendations.

February 2025

Scenario Results

Review the initial results of the model ensemble, discuss initial interpretations of the results, and gather feedback.

May 2024

Scenario Design #3

Review updated draft TM from scenario design workshop #2, discuss MPI/undesirable result thresholds for interpreting future model results.

April 2025

May 2024

Calibration #2

Summarize calibration workshop #1 and feedback gathered since then. Present updates and draft TM that will be published between calibration workshops #1 and #2.

Draft 2025 SYR Report

Review the draft 2025 SYR Report and gather feedback.

Dates of future meetings subject to change.

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Watermaster’s function is to administer and enforce provisions of the 1978 Judgment and subsequent orders of the Court, and to develop and implement an Optimum Basin Management Program.Working with the diverse interests of all stakeholders to administer the Judgment and preserve a resource as vital as groundwater in Chino Basin is the most rewarding and meaningful challenge of my 35 year career in water management.

- Peter Kavounas, P.E., General Manager

Watermaster’s Function:

Collaborative Approach

Watermaster administers and enforces

Watermaster values

the 1978 Judgment and implements an

teamwork, collaborating

Optimum Basin Management Program,

with experts and staying

working with diverse stakeholders to

connected with stakeholders

preserve Chino Basin’s groundwater.

and governing agencies.

CHINO

BASIN WATERMASTER

Quality and Transparency Watermaster is committed

Watermaster’s vision is to add value,

to high-quality work and

promote transparency, and educate

transparency, aiming to educate

stakeholders, ultimately benefiting

stakeholders on Judgment provisions for effective resource 8

Vision for Success

management.

their customers through efficient resource management.

What’s Next in October...

“Anything is possible when you have a path, a plan and a desire to take action.”

— Dean Graziosi Water Quality Committee & Water Quality Management Plan

OCTOBER 18 Reconvening the Water Quality Committee Kick-off meeting of the Committee to initiate the process to develop and Water Quality Management Plan at 1pm at the Watermaster’s office: 9641 San Bernardino Road, Rancho Cucamonga, CA 91730. All interested stakeholders are welcome!

History of Successful Management Water Quality Management We will be publishing a memo providing background on water quality management in the Chino Basin and opportunities for future enhancements and successes

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Chino Basin

Watermaster

OCTOBER 2023 UPDATE

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