Agenda packet — Corona City Council, June 3, 2026 (part 14 of 19)

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 12 • Was the process transparent such that stakeholders and the public can understand what important discussions are taking place, how they can participate in them, and how input is being used ensured?
The following information can also be collected and used as indicators:
• Interested Party List Additions: Number of contacts added to the list since the last workshop.
• Social Media Interactions: Number of likes, comments, and shares. • Public Workshops Attendance: Number of attendees and change over time. • Public Workshop Feedback: Public workshops will end with a poll and/or short survey, asking attendees how they learned about the workshop, recommending means for getting the word out to other community members, what they liked about the format, and what they liked least.

The evaluation input will inform the adaptation of subsequent outreach and involvement activities.

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Appendix A
Temescal Subbasin Map

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City of Norco
Service Area
Home Gardens
County Water District
Service Area Temescal
Subbasin
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Temescal Subbasin Groundwater Sustainability Agency (GSA) City of Corona Service Area
City of Norco Service Area
Home Gardens County Water District Service Area
Temescal Subbasin of the Upper Santa Ana Valley Groundwater Basin Exhibit A
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Groundwater
Sustainability Agency
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Appendix B
List of Interested Parties

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TEMESCAL VALLEY SUBBASIN

GROUNDWATER SUSTAINABILITY AGENCY

LIST OF PARTIES INTERESTED IN THE TEMESCAL SUBBASIN
The following list satisfies Water Code Section 10723.2, which states: a GSA shall consider the interests of all beneficial uses and users of groundwater, as well as those responsible for implementing Groundwater Sustainability Plans (GSPs). The list of interested parties presented below has been developed for the GSA. Many of the agencies identified below have already been contacted by the parties to the MOU for the GSA. The interests of all the agencies, organizations, and individuals identified below shall be considered during the development of the GSP for the GSA.

1. Local Water Districts within or adjoining the GSA:
a. Metropolitan Water District of Southern California
b. City of Riverside
c. The MOU/GSA member agencies
d. Western Municipal Water District (adjacent to the subbasin/GSA) e. City of Eastvale (adjacent)
f. City of Chino Hills (adjacent)
g. Jurupa Community Services District (adjacent)
h. Temescal Valley Water District (adjacent)
i. Eagle Valley Water District (adjacent)
j. Orange County Water District (adjacent)
k. Orange County Water Public Works Department (adjacent) l. Inland Empire Utilities Agency (adjacent)
m. Chino Basin Water Management District (adjacent)

2. Holders of Overlying Groundwater Rights:
a. There are a limited number of known agricultural, industrial, and domestic well owners that account for a very small proportion of subbasin annual groundwater use. These existing pumpers include the Dairy Farmers of America and other small producers. Known pumping is tracked on behalf of the Santa Ana River Watermaster, and these producers interests will be considered during the development of the GSP for the subbasin. b. Municipal and Industrial Well Operators
i. The MOU/GSA member agencies are the only municipal well operators within the Temescal Subbasin
ii. All American Asphalt, Dart Container Corporation of California, and Minnesota Mining and Manufacturing Corporation operate
industrial supply wells in the subbasin. Known pumping is tracked on behalf of the Santa Ana River Watermaster, and these producers interests will be considered during the development of the GSP for the subbasin.

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3. Surface Water Users
a. Santa Ana Watershed Protection Authority
b. Santa Ana River Watermaster. The Santa Ana River overlies portions of the Basin. Surface flows in the Santa Ana River are monitored by the Santa Ana River Watermaster. The Santa Ana River is adjudicated and minimum flows are required to reach the Prado Basin on an annual basis. c. The MOU/GSA member agencies

4. Environmental Users of Groundwater
a. Riverside County Flood Control and Water Conservation District b. Santa Ana River Watermaster
c. California Regional Water Quality Control Board - Santa Ana Region (8)

5. Local Land Use Planning Agencies
a. Riverside County, Planning Department
b. City of Corona
c. City of Norco

6. The Federal Government
a. United States Army Corps of Engineers (Prado Dam Management Area) b. United States Forest Service

7. California Native American Tribes
a. Not present within the Temescal Subbasin or proposed GSA area.

8. Disadvantaged Communities
a. There are 21 Census block groups within the City of Corona where median income is below the threshold for disadvantaged communities, and 13 of these block groups are below the severely disadvantaged community income threshold.
b. There are 4 Census block groups within the Home Gardens County Water District where median income is below the threshold for severely disadvantaged communities.

9. CASGEM Agencies
a. Western Municipal Water District is the monitoring entity responsible for CASGEM program in the Temescal Subbasin

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Appendix C
Disadvantaged and Severely
Disadvantaged Communities Map

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November 2017 Disadvantaged and
Severely Disadvantaged
Community Block Groups
Temescal Subbasin
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Disadvantaged Community
Severely Disadvantaged Community
Temescal Subbasin
(
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0 3,000 6,000
Scale in Feet
C-1

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Appendix D
Protocol and Operating Principles
for Temescal GSA Technical
Advisory Commitee

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1 Protocols and Operating Principles for
Temescal Subbasin
Groundwater Sustainability Agency
Technical Advisory Committee
August 7, 2020

1. INTRODUCTION
The State of California Sustainable Groundwater Management Act (SGMA), passed in 2014, calls for the development and implementation of groundwater sustainability plans for all basins determined high and medium priority by the California Department of Water Resources. Under SGMA, these basins should reach sustainability within 20 years of implementing their sustainability plans with a deadline of 2042. SGMA gives local agencies authority to define and plan for achieving and maintaining sustainable groundwater management while avoiding specific undesirable results through the preparation and implementation of a Groundwater Sustainability Plan (GSP).

The Temescal Subbasin, a medium-priority basin, lies mostly within the boundaries of the cities of Corona and Norco, and Home Gardens, an unincorporated area of Riverside County within the City of Corona’s sphere of influence. The Temescal Subbasin GSA (GSA) was formed by a Memorandum of Understanding among the City of Corona, the City of Norco, and the Home Gardens County Water District. The GSA is dedicated to participating in the collective goals of groundwater sustainability and good basin management through the development of a GSP for the Temescal Subbasin.

GSAs must consider the interests of all beneficial uses and users of groundwater and provide opportunities for public engagement and the Temescal Subbasin GSA is seeking active involvement of diverse social, cultural, and economic elements of the population. In order to achieve those requirements and provide more opportunities for stakeholders to represent diverse interests and provide input to inform GSP preparation, the GSA chose to form a Technical Advisory Committee (TAC). This document establishes the protocols and operating principles and records the charge and role of the TAC in GSP preparation, collaborative principles, meeting logistics information, and additional considerations for productive meetings where all TAC members can participate equally and effectively.

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2 2. CHARGE
The purpose of the TAC is to provide input and guidance to the staff and consultant team of the GSA who are preparing the GSP. At the request of the GSA, the TAC members will provide input and feedback on GSP development and implementation and GSA policies based on their expertise, knowledge, resources, and understanding of their communities, environment, commerce, and applicable regulations. The GSA and the project team will consider the TAC’s input throughout GSP preparation, along with input from the broader community, other stakeholders, and other government agencies involved in groundwater management and associated regulatory requirements.

Additionally, Technical Advisory Committee members represent the diverse interests of GSAeligible agencies and groundwater uses and users. The intent of the Technical Advisory Committee is to contribute community and stakeholder perspectives and interests in GSP planning and GSP and SGMA implementation in the Temescal Subbasin.

The Technical Advisory Committee will provide review and guidance to the GSA on groundwater-related issues during the development of the GSP that may include:
• Sustainability goals and objectives
• Monitoring programs
• Annual work plans and reports
• Modeling scenarios
• Inter-basin coordination activities
• Projects and management actions to achieve sustainability • Community outreach, including engagement with disadvantaged communities • Local regulations to implement SGMA
• General advice

3. ROLES AND RESPONSIBILITIES
To accomplish the above charge, Technical Advisory Committee members agree to the following:
• Contribute input towards long-term sustainable management of the Temescal Subbasin based on their knowledge and expertise in policy, technical, and community matters • Communicate to other stakeholders and community members about the GSA, GSP process, and SGMA
• Work collaboratively with others on the Technical Advisory Committee • Commit time needed to review material and participate in ongoing discussions • Collectively reflect diversity of interests
• Represent constituents’ perspectives, but also consider broader community input and input from other members during Technical Advisory Committee meeting discussions

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3 • Participate in all Technical Advisory Committee meetings for the entire planning process • Partner with the GSA and project team in publicizing public involvement activities

4. PARTICIPATION AND COLLABORATION PRINCIPLES
All Technical Advisory Committee members will work together to create a collaborative, problem-solving environment. The preferred deliberation process is a collaborative process whereby Technical Advisory Committee members choose to cooperate to achieve shared and/or overlapping objectives, in support of the GSA’s direction for the creation of a GSP for the Temescal Subbasin.

By agreeing to serve on the Technical Advisory Committee, members commit to the following principles:
• Commit to a good faith effort.
• Use common conversational courtesy.
• All ideas and point of view have value. All ideas have value in this setting. We are looking for innovative ideas. The goal is to achieve understanding. Simply listen, you do not have to agree. If you hear something you do not agree with or you think is “silly” or “wrong,” please remember that the purpose of the forum is to share ideas. • Be honest, fair and as candid as possible. Help others understand you and work to understand others.
• Share relevant information.
• Avoid editorials. It will be tempting to analyze the motives of others or offer editorial comments. Please talk about your own ideas and thoughts. Avoid commenting on why you believe another participant thinks something.
• Honor time and be concise. People’s time is precious; treat it with respect. • Think innovatively and welcome new ideas. Creative thinking and problem solving are essential to success. Attempt to think about the problem in a new way. • Seek solutions for all – help to integrate each other’s interests into creative solutions that address diverse needs.
• Invite humor and good will.

Meetings will be conducted using a facilitator, who will:
• Maintain a neutral position during Technical Advisory Committee discussions. • Work to ensure that all Technical Advisory Committee members have the opportunity to participate equally.
• Guide meeting discussions per the agenda and manage time. • Provide dialogue activities as needed for productive outcomes. • Enforce the Technical Advisory Committee collaboration principles stated above. • Ask “why” to clarify interests.

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4 • Track actions, next steps, and deadlines.
• Participate in agenda preparation as part of meeting the above responsibilities and integrating the Technical Advisory Committee in the planning process.

5. MEMBERSHIP
The intent of the Technical Advisory Committee is to provide broad participation and advice to the GSA. To facilitate effective meetings and manage group size, the Technical Advisory Committee will not exceed 18 members.

The GSA Staff (made up of City of Corona Department of Water and Power staff) will manage its membership and composition and the Staff may make appointments from time-to-time after receiving Technical Advisory Committee recommendations from interested parties to serve on Technical Advisory Committee. When an organization’s representative is no longer able to serve, the organization will recommend a new representative to the Technical Advisory Committee. If the organization withdraws from the Technical Advisory Committee, the Technical Advisory Committee and Staff will identify another organization and corresponding representative to fill that seat and recommend the organization to the GSA for appointment.

The Technical Advisory Committee strives to include a range of interests in groundwater in the Temescal Subbasin as outlined in SGMA. Technical Advisory Committee members live in the Temescal Subbasin or represent organizations with a presence or agencies with jurisdiction in the Subbasin, including:
• All Groundwater Users
• Municipal Well Operators, Public Utilities Commission-Regulated Water Companies, and Private and Public Water Systems
• County and City Governments
• Planning Departments/Land Use
• Local Landowners
• Disadvantaged Communities
• Business and Agriculture
• Rural Residential Well Owners
• Environmental Users
• Water Supply and Management Surface Water Users (if connection between surface and ground water)
No Technical Advisory Committee member shall be compensated by the GSA for preparation for or attendance at meetings of the GSA or any committee created by the GSA. The fiscal responsibility of the Technical Advisory Committee falls under the oversight of the GSA.

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5 6. REQUEST FOR NO USE OF ALTERNATES
The GSA requests that once each Technical Advisory Committee member identifies its representative, each representative will commit to attending all meetings in person for the duration of the study. The meetings will build on each other, where discussions in one meeting will shape and inform the discussions at the next meeting. Because continuity is only optimized by consistency in attendance and participation by the representatives, the GSA has established a “no alternate” policy.

7. TERM OF SERVICE
The Technical Advisory Committee is being formed with an understanding that it will serve through submittal of the GSP by January 31, 2022.

8. MEETING LOGISTIC AND COMMUNICATION
Project Duration
The final GSP will be submitted to the State of California Department of Water Resources by January 31, 2022.

Meeting Schedule and Length
There will be four Technical Advisory Committee meetings, currently scheduled for Summer 2020, Fall, 2020, Winter 2021, and Spring 2021. Meetings will last 2 to 4 hours.

Meeting Location
The first Technical Advisory Committee meeting will take place as a virtual meeting online, largely due to restrictions implemented in response to COVID-19. The GSA and project team will assess the latest State and local social distancing requirements and guidance to determine inperson and online venues for future meetings.

Agendas
Agendas will be distributed via email one week in advance of each meeting.

Meeting Summaries
Meeting summaries will be prepared and distributed.

9. COMMUNICATION & MEDIA
GSA Staff will serve as primary contacts for all communication, outreach and media. At the request of the GSA, or Staff, the Technical Advisory Committee may advise on outreach and community engagement.

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6 Media Interaction
Technical Advisory Committee members reserve freedom to express their own opinions to media representatives, but not the opinions of others. The temptation to discuss someone else’s statements or position should be avoided. Participants can refer media inquiries to Technical Advisory Committee members for individual comments.

If contacted by the press or an external party concerning discussions, participants are asked to:
• Point out that they are not speaking on behalf of the Technical Advisory Committee, unless specifically authorized by the Technical Advisory Committee to do so • Present their views only and conscientiously refrain from expressing, characterizing or judging the view of others
• Avoid using the press as a vehicle for negotiation
Member-To-Member Communications
Technical Advisory Committee members may want to share information and documents with other members during the study process. To ensure that all members have the same information available to them, all documents are to be distributed through the established point of contact, who is listed at the end of this document.

The Technical Advisory Committee is intended to be a collaborative experience, in which members work through ideas, issues and solutions in person to gain mutual understanding. As such, Technical Advisory Committee members agree to avoid engaging in email “dialogue” with other members outside the meeting process, and instead commit to using the Technical Advisory Committee meetings for dialogue and discussion purposes.

10. OPEN MEETINGS
All Technical Advisory Committee meetings will be open to the public and announced in advance on the project website. Meeting materials and summaries for each meeting will be posted on the project website.

11. POINT OF CONTACT FOR TECHNICAL ADVISORY COMMITTEE

MEMBERS
The established point of contact for Technical Advisory Committee members’ questions, suggestions, and input is Melissa Estrada-Maravilla, who is reachable by email at Melissa.Estrada[email protected] or phone at 951.736.2479.

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Temescal Basin GSP

APPENDIX E
List of Public Meetings During GSP
Development and GSP Comments and
Responses

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Temescal Basin GSP
Public Meetings Held During Development of the Temescal Basin Groundwater Sustainability Plan
August 19, 2020 – Temescal Basin Technical Advisory Committee Meeting 1 November 18, 2020 – Temescal Basin Technical Advisory Committee Meeting 2 February 17, 2021 – Temescal Basin Technical Advisory Committee Meeting 3 June 16, 2021 – Temescal Basin Technical Advisory Committee Meeting 4 September 29, 2020 – Public Workshop 1 for Temescal Basin Groundwater Sustainability Plan Development
March 2, 2021 – Public Workshop 2 for Temescal Basin Groundwater Sustainability Plan Development
July 8, 2021 – Public Workshop 3 for Temescal Basin Groundwater Sustainability Plan Development

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Temescal Basin GSP

APPENDIX F
Summaries of Technical Advisory Committee
Meetings

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Technical Advisory Committee Meeting #1
Meeting Summary
Wednesday, August 19, 2020
2:00 p.m. – 4:00 p.m.

Location: Zoom Virtual Meeting
Attendees
Technical Advisory Committee Members
• Ava Moussavi, Riverside County Flood Control and Water Conservation District • Chad Blais, City of Norco Public Works Department
• David Vigil, Home Garden County Water District
• Eric Lindberg, California Regional Water Quality Control Board – Santa Ana Region • Jacque Casillas, Vice Mayor, City of Corona
• Katie Hockett, City of Corona Department of Water and Power • Roberta A. Reed, 3M Industrial Mineral Products Division • Timothy Ballon, All American Asphalt
• Tom Moody, City of Corona Department of Water and Power • Wes Speake, Councilmember, City of Corona
City of Corona Department of Water and Power Staff
• Kristian Alfelor
• Melissa Estrada-Maravilla
Consultant Team
• Chad Taylor, Todd Groundwater
• Phyllis Stanin, Todd Groundwater
• Alyson Scurlock, Kearns & West
• Jack Hughes, Kearns & West
• Joan Isaacson, Kearns & West
Summary

1. Welcome and Introductions
Tom Moody, General Manager at the City of Corona Department of Water and Power, welcomed all to the first meeting of the Temescal Groundwater Sustainability Agency Technical Advisory Committee (TAC). He introduced Todd Groundwater, Carollo Engineers, and Kearns & West as the consultants assisting the Temescal Groundwater Sustainability Agency (Temescal GSA) with preparation of the Temescal Groundwater Sustainability Plan (Temescal GSP) and meeting facilitation. 1

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2. Overview of Meeting Agenda
Joan Isaacson serving as TAC meeting facilitator, Kearns & West, led roundtable introductions for all attending. Isaacson thanked all for attending since their expertise, track record of working collaboratively with other agencies and organizations, and relationships with communities and other stakeholders would be very valuable throughout preparation of the Temescal GSP. She then reviewed the meeting agenda (see Appendix A), noting that the meeting would focus on an introduction to the Sustainable Groundwater Management Act (SGMA), Temescal GSP workplan and schedule, Outreach and Stakeholder Involvement Communications Plan, and TAC members’ roles.

3. Orientation to the Sustainable Groundwater Management Act Chad Taylor, Senior Hydrogeologist at Todd Groundwater, presented the background and purpose of SGMA, an overview of the Temescal Basin and Temescal GSA, and the Temescal GSP development timeline. SGMA is California State legislation that establishes requirements and specifies deadlines for achieving and maintaining groundwater sustainability. These requirements include forming a GSA and preparing a GSP to facilitate local groundwater management informed by stakeholders. SGMA requires that groundwater basins designated as medium (such as the Temescal Basin) or high priority form GSAs and file GSPs by January 31, 2022 and subsequently demonstrate sustainable groundwater management by 2042. See page 10 in Appendix B for map of the Temescal Basin. Sustainability, as defined in SGMA, is the local management and use of groundwater in a way that can be maintained without experiencing undesirable results. SGMA requires evaluation of undesirable results in consideration of six sustainability indicators which are chronic lowering of groundwater levels; reduction of groundwater storage; degradation of water quality; depletion of interconnected surface water affecting beneficial uses; land subsidence affecting land uses; and seawater intrusion.

Taylor explained that the City of Corona, the City of Norco, and Home Gardens County Water District formed the Temescal GSA in 2017 through a memorandum of understanding. The Temescal GSA will work with the California Department of Water Resources (DWR), the TAC, consultants, residents, local public, and other agencies and stakeholder organizations during the Temescal GSP preparation.

The Temescal GSA has begun the process of developing and implementing a GSP for the Temescal Basin, including data gathering and review, preparation of a Draft Plan Area Chapter, and preparation of an Outreach and Stakeholder Involvement Communications Plan. For more information on the Temescal GSA, see pages 11 through 12 in Appendix B.

Discussion/Q&A
The team opened the floor for questions and discussion. Taylor listed two discussion questions for consideration: 1) What have you heard about groundwater and/or SGMA and what do you think are some important groundwater management issues? 2) Are you aware of any data or studies we should review during GSP preparation? Discussions, comments, and questions are summarized below. • The State of California requires local municipal organizations to serve as GSA partners, so private companies are not eligible, but they can participate in GSP preparation in other ways. • The Temescal Basin has a current Groundwater Management Plan and the majority of water after a rainfall event goes to local recharge. This is interesting, and we should find a way to inform the public on how this happens in the Temescal Basin, so they can know about it and understand it.
2

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• The fact sheet sent prior to this meeting was great. The public should know that the GSA agencies have been and are good stewards of our groundwater. • Other GSPs have considered what it would mean to decrease water use in the future and that is a concern this TAC should think about.
• It is important that TAC members work with and train others in their agency or organization in consideration of the 2042 sustainability mark so that there is capacity for someone to provide input over 20 years.
• Let’s not shy away from talking about Direct Potable Reuse and Indirect Potable Reuse projects as part of this process. They can be hard to talk about but should be talked about sooner rather than later as they are a big part of groundwater replenishment.

4. Summary of Groundwater Sustainability Plan Workplan and Schedule Taylor provided a summary of the Temescal GSP workplan and schedule. The Temescal GSP will build from past and existing management activities, including the 2008 Groundwater Management Plan.

Major Temescal GSP elements include data compilation; plan area; hydrogeologic conceptual model; groundwater model; sustainability goals and criteria; management actions, projects, and monitoring; and plan development. Data compilation and a Draft Plan Area Chapter are already complete. The next steps are to develop the hydrogeological conceptual model, assess current and historical groundwater conditions, and construct a numerical groundwater model. These will be used to calculate groundwater budgets and sustainable yield, so that it is known how much groundwater is available for use. After that comes the creation of sustainability goals and criteria, which define what sustainability means in the Temescal Basin. Next, management actions will be identified to meet sustainability goals and criteria and a monitoring program will be established.

Taylor reviewed the Temescal GSP preparation schedule noting that there will be four TAC meetings total and three public workshops and a presentation of the Draft GSP during the process. The Draft Temescal GSP will be made available for public review in Summer 2021. The final Temescal GSP will be completed by Fall 2021 prior to submittal to DWR. See pages 13 through 16 in Appendix B for more information on the Temescal GSP workplan and schedule.

Discussion/Q&A
There were no questions or comments from the TAC members for this agenda item.

5. Outreach and Involvement
Jack Hughes, Kearns & West, provided an overview of the purpose, objectives, and components of the Outreach and Stakeholder Involvement Communications Plan. The purpose is to provide a framework for integrating public and stakeholder outreach and involvement into the Temescal GSP preparation. The objectives include making sure all stakeholders are informed of the Temescal GSP process and how they can get involved; providing meaningful opportunities for stakeholders and the public to learn and provide input; involving the diverse communities and stakeholders of Corona, Norco, and Home Gardens; and ensuring a transparent process. An important component is involving communities and stakeholders with diverse groundwater interests.

Hughes reviewed the planned outreach and involvement activities included in the plan and how they would be aligned with the Temescal GSP planning steps. The public will have opportunities to get information and provide comment during the public workshops and/or during the presentation on Temescal GSP updates provided during the City Council or Board of Directors meetings of each 3

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respective Temescal GSA member. There will also be three public workshops. Each workshop will be accompanied by several methods of pre-workshop outreach to boost attendance and circulate information such as emails, social media posts, and distributing fact sheets.

Hughes noted the importance of engaging underrepresented communities throughout the Temescal GSP process. He displayed areas in the Temescal Basin that DWR has identified as Disadvantaged Communities and Severely Disadvantaged Communities. The consultant team has talked with local community leaders to discuss strategies and best practices for conducting engagement with underrepresented communities and what community organizations will be important to partner with.

Hughes then overviewed the outreach materials being developed in preparation for the first public workshop. The Temescal GSA website (www.CoronaCA.gov/Groundwater) will serve as a hub for project information and updates. It will include a comment form for anyone to contribute input during the Temescal GSP process. The Temescal GSA fact sheet (see Appendix C) introduces broader groundwater concepts to bring public awareness to local groundwater resources in addition to information about SGMA and the Temescal GSP. The first public workshop is tentatively scheduled for September 29, 2020 and will be held virtually. See pages 17 through 24 in Appendix B for more information on outreach and involvement.

Discussion/Q&A
Hughes posed the following questions for discussion: 1) How can we reach more of your community members, constituents/other stakeholders, and the public in our pre-workshop outreach? 2) How might you be able to help us spread awareness of the first public workshop? • The TAC discussed what stakeholders had already been identified. A working list has been developed that includes many agencies, businesses, private pumpers, and other stakeholders upstream and downstream, as well as those in neighboring basins. TAC members can suggest additional interested parties to add. The website, via the comment page, provides an additional option for anyone interested in signing up for updates. • The TAC discussed if the project team had target numbers for engagement in underrepresented communities in mind. There are no target numbers for engagement. • One question asked was, how many members of the public attended public meetings for other GSPs? A member of the consultant team stated that the public attendance at public meetings for other GSPs varies. Depending on the Basin, attendance has ranged from zero members of the public and several agency representatives to many members of the public and agency representatives.
• The idea of a focus group was also mentioned. One suggestion was to incentivize participation by offering gift cards or coupons. People in line at bi-weekly food drives at city hall could be engaged. Another idea was to encourage people to answer a one-question survey that drives them to the project website. TAC members discussed options for what that question could be. • The TAC noted that the fact sheet was very good but might be a little too dense, and it could maybe be reduced to one-page with English on one side and Spanish on the other.

6. Role of the Technical Advisory Committee
Isaacson explained the role of the TAC and reviewed the TAC Protocols and Operating Principles document (see Appendix D), which was provided to TAC members before the meeting. The general purpose of the TAC is to provide input and guidance to the Temescal GSA and consultant team during 4

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the development of the Temescal GSP. TAC members represent diverse groundwater interests and will work collaboratively to contribute input towards long-term sustainable management of the Temescal Basin, communicate with additional stakeholders and community members about the Temescal GSA, Temescal GSP process, and SGMA, review material and participate in ongoing discussions, and help to publicize public involvement activities. TAC members were asked to provide a general confirmation of the operating protocols and to reach out to the project team contact (Melissa Estrada-Maravilla) if they saw any red flags.

Discussion/Q&A
There were no questions or comments from the TAC members for this agenda item.

7. Public Comment
No members of the public provided comment.

8. Next Steps and Final Comments
Isaacson summarized next steps for the TAC members. Following this meeting, Estrada will send out the Draft Plan Area Chapter of the Temescal GSP for TAC members to review. The consultant team will continue preparing the technical analyses. Comments on the Draft Plan Area Chapter of the Temescal GSP are due to the GSA on September 4, 2020. Additional next steps are preparing for the upcoming public workshop tentatively scheduled for September 29, 2020 and the next TAC meeting on November 18, 2020.

Discussion/Q&A
• The time for the first public workshop was discussed. A start time before 6:00 p.m. would be good as it is difficult to conduct a virtual public workshop later in the evening. Also, the timing of future workshops could be alternated to see what works best. 5

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Technical Advisory Committee
Temescal Subbasin Groundwater Sustainability Agency
August 19, 2020

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How to Mute and Start/Stop Video

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To Select Best View

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How to Rename Yourself – Step 1

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How to Rename Yourself – Step 2

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How to Raise Your Hand– Step 1

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How to Raise Your Hand – Step 2

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Welcome and Introductions

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Introductions
• Name
• Who you are representing
• What have you been pleasantly surprised by recently?

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Why the Temescal Groundwater
Sustainability Agency Needs You

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Tips for a Productive Discussion
• Let one person speak at a time
• Help make sure everyone gets equal time to give input • Keep your input concise so others have time to participate • Actively listen to others and seek to understand their perspectives
• Offer ideas to address questions and concerns raised by others

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Overview of Meeting Agenda

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Meeting Agenda

1. Welcome and Introductions

2. Overview of Meeting Agenda

3. Orientation to the Sustainable Groundwater
Management Act
• Sustainable Groundwater Management Act (SGMA)
Overview
• Temescal Subbasin GSA
• Discussion/Q&A

4. Summary of GSP Workplan and Schedule
• GSP Workplan and Schedule
• Discussion/Q&A

5. Outreach and Involvement
• Outreach and Stakeholder Involvement Plan
• Focus on Disadvantaged Community Engagement
• Website Overview
• Fact Sheets
• Public Workshop 1
• Discussion/Q&A

6. Role of the Technical Advisory Committee
• Technical Advisory Committee (TAC) formation and purpose • Draft TAC Protocols and Operating Principles and Confirmation • Discussion of TAC roles and responsibilities

7. Public Comment

8. Next Steps and Final Comments

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Orientation to the Sustainable
Groundwater Management Act

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Sustainable Groundwater Management Act (SGMA)
Landmark legislation signed into law in 2014
• Provides framework for sustainable groundwater
management
• Purpose is to facilitate local management of groundwater • State assistance, and intervention if necessary
Includes comprehensive requirements for:
• Forming groundwater sustainability agencies (GSA)
• Preparing groundwater sustainability plans (GSP)
• Meeting deadlines

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SGMA has a required timeline
2040/2042
Achieve and
demonstrate
sustainability
Today

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Achieving
sustainable
groundwater
management

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What is Sustainable Groundwater
Management?
• The management and use of groundwater in a manner that can be maintained without causing undesirable results
• Evaluated with respect to specific Sustainability Indicators • Locally defined

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The Temescal Basin
• DWR categorized as a Medium Priority
Basin
• Contiguous and connected

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Groundwater Sustainability Agency for the
Temescal Basin
• Managed together historically
• Corona, Norco, and Home Gardens
County Water District formed GSA led by
Corona
• Allows for preparation of one, unified GSP

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GSA Organization
Staff and Consultants
• Corona DWP Staff
• Todd Groundwater
• Carollo Engineers
• Kearns & West
City of Corona
Technical Advisory Committee
• Public agencies
• Local business community
• Well owners
• Community interests
Other agencies and interested parties
Department of Water and Power
City of Norco
Home Gardens County
Water District

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To Date, the Groundwater
Sustainability Agency
• Awarded grant for GSP preparation
• Assembled GSP team
• Initiated technical work on GSP
• Created outreach plan
• Formed TAC
• Creating new SGMA section on DWP
website

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Discussion / Q&A
• What have you heard about groundwater and/or SGMA and what do you think are some important groundwater management issues? • Are you aware of any data or studies we should review during GSP preparation?

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Summary of GSP Workplan and
Schedule

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The GSP will Build on
Existing Management
• Local groundwater
• Imported water
• Water recycling and water conservation
• Monitoring
• Collaboration with other local agencies
• Transition to SGMA requirements

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Temescal GSP Overview
Data Compilation /
Management System
Evaluate sustainability indicators
Define undesirable results
Establish minimum thresholds
Evaluate hydrogeologic setting
Define groundwater conditions
Identify and evaluate actions
Establish monitoring program
Construct numerical groundwater model
Calculate water budgets and sustainable yield
Plan Area / Institutional
Setting
Hydrogeologic Conceptual
Model / GW Conditions
Groundwater Model /
Water Budgets
Sustainability Goals and
Criteria
Management Actions,
Projects, and Monitoring
Plan Development

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Sustainability Indicator Requirements
− Groundwater elevation decline based on historical trends, water year type, and projected water use in the basin
− Sustainable yield, calculated based on historical trends, water year type, and projected water use in the basin
− Number of supply wells, volume of water, or location of an isocontour exceeding constituents of concern, considering state and federal standards − Depletion that has adverse impacts on beneficial use of surface water supported by the location, quantity, and timing of depletions; assumes use of a numerical model. − Rate and extent of subsidence that interferes with surface land use supported by identification of land/property interests affected or likely to be affected.

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Considerations for Temescal
− Historic low levels? Consider beneficial uses of wells; problems during the recent drought?
− Use Water Level criteria? Develop operational range of storage with an emergency supply?
− Title 22, basin plan objectives, GAMA, GeoTracker, SNMP? − Interconnected Surface Water and Groundwater Dependent Ecosystems (GDEs), Prado area?
− Subsidence does not currently interfere with land uses – Must be water levels in representative wells.
– Related to water levels.
– Should coordinate with existing regional programs.
– Can take advantage of statewide satellite estimates.
– Modeling to identify potential undesirable results.

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GSP Schedule 2021
2020
Data Compilation /
Management System
Plan Area / Institutional
Setting
Hydrogeologic Conceptual
Model / GW Conditions
Groundwater Model /
Water Budgets
Sustainability Goals and
Criteria
Management Actions,
Projects, and Monitoring
Plan Development

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TAC Meetings and Workshops
Public Workshop 1
Kickoff and Introduction to
SGMA (Q3 2020)
Public Workshop 2
Sustainability Criteria (Q1 2021)
Public Workshop 3
Management Actions (Q2 2021)
Draft GSP Presentation
(Q3 2021)
Data Compilation /
Management System
Plan Area / Institutional
Setting
Hydrogeologic Conceptual
Model / GW Conditions
Groundwater Model /
Water Budgets
Sustainability Goals and
Criteria
Management Actions,
Projects, and Monitoring
Plan Development
2021
2020 TAC Meeting 1 – August 19, 2020
TAC Meeting 2 – November 18, 2020
TAC Meeting 3 – February 17, 2021
TAC Meeting 4 – May 19, 2021

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GSP Workplan and Schedule Discussion/Q&A
Questions?
Comments?

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Outreach and Stakeholder Involvement

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Outreach and Stakeholder Involvement Plan
Purpose
• Provide a framework for integrating public and stakeholder outreach and involvement into GSP preparation.
• Meet SGMA requirements
• GSAs must consider the interests of all beneficial uses and users of groundwater and provide opportunities for public engagement and active involvement of diverse social, cultural, and economic elements of the population.

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Outreach and Stakeholder Involvement Plan
Objectives
• Inform all stakeholders of the GSP development process, including purpose, opportunities and issues, core recommendations, and timeline.
• Provide meaningful opportunities for stakeholders and the public to learn, ask questions, and provide input.
• Involve the many diverse communities and stakeholders of Corona, Norco, and Home Gardens, recognizing that different approaches may be needed to reach specific populations like Disadvantaged Communities, and flexibility and adaptation in approach may be required. • Ensure a transparent process where stakeholders and the public can understand what important discussions are taking place, how they can participate in them, and how input is being used.

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Outreach and Stakeholder Involvement Plan
Stakeholder Categories
• Agriculture
• California Statewide Groundwater
Elevation Monitoring Agencies
• Businesses and Development
• Disadvantaged Communities
• Domestic Well Owners
• Environmental and Conservation
• Extractive Industry
• Federal Government Agencies
• Groundwater Right Holders
• Industrial Well Operators
• Land Use Planning Agencies
• Local Water Districts
• Municipal Well Operators
• Private Water Users
• Regulatory Agencies
• Surface Water Users

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Outreach and Stakeholder Involvement Plan

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Outreach and Stakeholder Involvement Plan
Activities
• Pre-Workshop Outreach
• Public Workshops
• Technical Advisory Committee Meetings
• City Council and Board of Directors Meeting Presentations • Public Comment Period

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Focus on Underrepresented
Community Engagement

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Underrepresented Community Engagement
Definition
Underrepresented Communities are:
• Disadvantaged Communities characterized by an annual median household income less than 80% of the California statewide median household income. • Severely Disadvantaged Communities are characterized by an annual median household income less than 60% of the California statewide median household income.

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Disadvantaged Communities in Project Area
Per DWR Mapping Tool

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Website

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Fact Sheet

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Public Workshop 1
• The first Public Workshop is tentatively scheduled for September 29th • Focus
• Introduction to SGMA and GSPs, the Temescal Basin, planning process, and resources

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Public Workshop 1 . . . Virtual + Inclusive
Creative and innovative tools will be
employed to accomplish workshop
objectives

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Discussion / Q&A
• How can we reach more of your community or constituents/other stakeholders and the public in our pre-workshop outreach? • How might you be able to help us spread awareness of the first public meeting?

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Role of the Technical Advisory
Committee

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TAC Protocols and Operating Principles
Introduction
Charge
Roles and Responsibilities
Participation and Collaboration
Principles
Membership
Request for No Use of Alternatives
Term of Service
Meeting Logistics and Communication
Communication and Media
Open Meetings
Point of Contact

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Technical Advisory Committee Contact
Melissa Estrada-Maravilla
Email: [email protected]
Phone: 951.736.2479

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Discussion of TAC Roles and Responsibilities
and Confirmation
Questions?
Comments?
Protocols and Operating Principles Confirmation

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Public Comment

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Next Steps and Final Comments

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Next Steps
• Continue Technical Analyses
• Prepare internal draft Hydrogeologic Conceptual Model and Groundwater Conditions chapters of the GSP
• Continue numerical model and water budget analysis
• Provide Administrative Draft Plan Area chapter of the GSP to TAC today, with all comments back by September 4th.
• Prepare for and hold Public Workshop 1 (September 29th) • Next TAC meeting November 18, 2020
• Update on technical analyses
• Conceptual sustainability criteria discussion

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Thank You!

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Technical Advisory Committee Meeting 2
Meeting Summary
Wednesday, November 18, 2020
1:00 p.m. – 3:00 p.m.

Location: Zoom Virtual Meeting
Attendees
Technical Advisory Committee Members
 Ava Moussavi, Riverside County Flood Control and Water Conservation District  Chad Blais, City of Norco Public Works Department
 Eric Lindberg, California Regional Water Quality Control Board – Santa Ana Region  Jacque Casillas, Vice Mayor, City of Corona
 Katie Hockett, City of Corona Department of Water and Power  Timothy Ballon, All American Asphalt
 Tom Moody, City of Corona Department of Water and Power  Wes Speake, Councilmember, City of Corona
City of Corona Department of Water and Power Staff
 Kristian Alfelor
 Melissa Estrada-Maravilla
Consultant Team
 Chad Taylor, Todd Groundwater
 Maureen Reilly, Todd Groundwater
 Alyson Scurlock, Kearns & West
 Jack Hughes, Kearns & West
 Joan Isaacson, Kearns & West
Summary

1. Welcome and Introductions
Joan Isaacson, meeting facilitator from Kearns & West, welcomed all to the second Technical Advisory Committee (TAC) meeting for the Temescal Basin Groundwater Sustainability Plan (Temescal GSP). The meeting took place online, via ZOOM, hosted by the Temescal Basin Groundwater Sustainability Agency (Temescal GSA). Isaacson led roundtable introductions for TAC members and the consultants assisting the Temescal GSA with meeting facilitation and preparation of the Temescal GSP.

2. Overview of Meeting Agenda
Isaacson reviewed the meeting agenda (see Appendix A). The focus of the meeting was on providing an overview of Public Workshop 1, reviewing Draft Temescal GSP chapters, and then reviewing and

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getting input from the TAC on beneficial uses, the Draft Temescal GSP Sustainability Goal, and Conceptual Sustainability Criteria.

3. Public Workshop 1
Jack Hughes, Kearns & West, recapped the attendance and engagement from the first public workshop on September 29, 2020 held from 4:00 to 5:30 p.m. The workshop was held virtually via the Zoom platform, individuals also had the option to view and participate from the City of Corona Council Chambers. The workshop was streamed on the City of Corona’s website, Facebook, and YouTube channels and on Corona TV, viewable on Channel 29 on Time Warner Spectrum and Channel 99 on AT&T. There were 13 participants on Zoom representing water districts, non-profits, and residents of the City of Norco and Riverside County. There were 452 Facebook engagements, which includes comments, likes, clicks, and shares, and 23 YouTube views as of November 6, 2020.

Hughes then described the input and feedback that was heard during and after the first public workshop. Participants asked questions about water quality early in the workshop when the project team was discussing water supply and groundwater basics. Later comments focused on coordination with stakeholders in neighboring basins when the project team was discussing the Temescal Basin and GSP development. Hughes noted that meetings with representatives from each neighboring basin are currently being set up to establish this coordination. Additional feedback was received in two postworkshop feedback forms regarding outreach and involvement. One participant suggested sending out questions or topics for discussion ahead of the workshops and another participant volunteered to make workshop announcements at pertinent Santa Ana Watershed Project Authority meetings. The next public workshop will take place in Spring 2021 and will focus on sustainability criteria. For more information, see Appendix B.

Discussion/Q&A
There were no questions or comments from the TAC members for this agenda item.

4. Draft Groundwater Sustainability Plan Chapters
Chad Taylor, Senior Hydrogeologist at Todd Groundwater, presented on the Draft Hydrogeologic Conceptual Model and Groundwater Conditions Chapters that were distributed to TAC members on November 17, 2020. Taylor provided an overview of the Temescal Basin, noting that it is a contiguous and connected basin that is categorized as medium-priority by the Department of Water Resources.

The Draft Hydrogeologic Conceptual Model Chapter establishes the physical framework of the basin while the Draft Groundwater Conditions Chapter documents the historical and current status of the basin. Future analyses will include the water budget, which will quantify inflows, outflows, and storage change in the Temescal Basin, and the numerical model, which will evaluate sustainability criteria, monitoring, and project and management actions.

Taylor reviewed highlights of the Draft Hydrogeologic Conceptual Model Chapter. The Temescal Basin is primarily comprised of young unconsolidated deposits and is surrounded by older bedrock on most of the western and eastern boundaries. In addition, faulting affects groundwater in much of the Temescal Basin, especially on the western side. Taylor displayed three cross section orientations that help illustrate subsurface conditions in the Temescal Basin, noting that only one cross section would be the focus in the presentation. Taylor showed Cross Section A to A’ and described the aquifers in the Basin. The Channel Aquifer has been identified as the principal aquifer used for groundwater production in the Temescal Basin. There are also two secondary aquifers in the Basin; they have historically been

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less productive alluvial and sandstone aquifers. Taylor noted that the most productive wells in the Temescal Basin, measured by hydraulic conductivity, are in the Channel Aquifer. The basin thickness, or depth to the bottom of the basin, varies and is deepest in the southwest portion of the Channel Aquifer.

Taylor next reviewed highlights of the Draft Groundwater Conditions Chapter. Groundwater flows consistently towards the northwestern portion of the Temescal Basin and towards the western portion in the Prado area. The Draft Groundwater Conditions Chapter also includes historical groundwater elevation conditions and trends. Taylor showed an example of a hydrograph and described basin-wide trends seen in wells. The highest water levels in most wells were measured in the early 1980s and the lowest water levels are generally present in periods of dry conditions and increased pumping. Taylor noted that current water levels are near record lows.

For water quality, the primary constituents of concern in the Temescal Basin are total dissolved solids and nitrate. Total dissolved solids were found to be highest in the productive portion of the Temescal Basin and nitrate was also found to be high in some areas, both of which will be considered for future management. The Temescal Basin has areas of interconnected surface water in addition to areas where groundwater dependent ecosystems will need to be addressed. Taylor described subsidence as vertical displacement of ground surface, which has been estimated from satellite measurements and noted that there is no evidence of subsidence in the Temescal Basin. Taylor also noted that monitoring of subsidence will continue to ensure there are no changes in the future. For more information on the Draft Hydrogeologic Conceptual Model and Groundwater Conditions Chapters, see Appendix B.

Discussion/Q&A
The team opened the floor for questions and discussion. Discussions, comments, and questions are summarized below.
 Can you provide more detail on the depth of bedrock estimates, how many wells there are, and what interpolation method was used?
 The water quality map shows wells with differing water quality clustered together. What would drive the difference in water quality in the same aquifer? It would be helpful to state that the wells are at different depths.

5. Input on Beneficial Uses
Taylor presented the preliminary list below of known beneficial uses in the Temescal Basin and asked for TAC members’ input on additional beneficial uses to include in the Temescal GSP.  Municipal water supply
 Industrial water supply
 Rural residential water supply
 Small community water system supply
 Small commercial water supply
 Groundwater dependent ecosystems in Temescal Wash and Prado Discussion and feedback from TAC members on beneficial uses included these comments:
 Cemetery landscaping uses groundwater.
 Industrial water supply includes mining as wash water is used for operations.

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 Mining operations use water for processing and dust control in the area.  It is important to understand the balance between local and imported resources in municipal water supply.
 Scattered residents have their own wells.
 Dust control for development could be included in municipal water supply and rural residential water supply.
 It would be interesting to find out if there are agricultural users in the Temescal Basin.  There are recreational water uses where groundwater and surface water interface. One known recreational use is a ski club in the Temescal Canyon Lake.

6. Draft Sustainability Goal and Conceptual Sustainability Criteria Taylor presented the Draft Sustainability Goal for TAC members’ feedback. The goal is tailored to the local meaning of sustainability and is the starting point for defining sustainability in the Temescal GSP.

The following Draft Sustainability Goal was presented:

To sustain groundwater resources for the current and future beneficial uses of the Temescal Basin in a manner that is adaptive and responsive to the following objectives:
 Provide a long-term, reliable, and efficient groundwater supply for municipal, industrial, and other uses;
 Provide reliable storage for water supply resilience during droughts and shortages;  Protect groundwater quality;
 Support beneficial uses of interconnected surface waters; and  Support integrated and cooperative water resource management.

Taylor explained the sustainability criteria required for evaluation according to the Sustainable Groundwater Management Act. The six sustainability indicators include chronic lowering of groundwater levels, reduction of groundwater storage, degradation of water quality, depletions of interconnected surface water affecting beneficial uses, land subsidence affecting land uses, and seawater intrusion (not applicable in the Temescal Basin). Taylor explained undesirable results, minimum thresholds, and measurable objectives. Undesirable results are significant and unreasonable conditions for any of the six sustainability indicators whereas minimum thresholds are numeric values used to define undesirable results. Measurable objectives are specific, quantifiable goals used to track the performance of sustainable management.

Taylor reviewed the six sustainability indicators and gave examples of undesirable results for each of them. He noted that subsidence, or the lowering of the ground surface due to the collapse of subsurface materials, is not a known issue in the Temescal Basin. Potential for undesirable results include reductions in drainage capacity, impacts on the grade of facilities, subsidence around a wellhead, and non-recoverable loss of storage capacity in the aquifers. The interconnected surface water indicator analyzes the relationship between water levels in a stream and groundwater for stream flow. When groundwater is higher, interconnected surface water flows from the groundwater to the stream.

The next indicator, groundwater storage, is directly connected to water levels, therefore this indicator can use water levels to establish minimum thresholds and measurable objectives to ensure that there is enough water to meet the needs of beneficial uses and users. The groundwater levels indicator will consider what undesirable effects should be avoided in the Temescal Basin, such as impacts to shallow

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wells and maintenance of municipal and industrial water supply. Lastly, the water quality indicator will establish a numeric value to define significant and unreasonable degraded water quality throughout the Temescal Basin. Taylor noted that local, state, and federal water quality standards should be considered. See Appendix B for more information on the Draft Sustainability Goal and sustainability criteria.

Discussion/Input
The team asked for feedback on the Draft Sustainability Goal.  The Draft Sustainability Goal and criteria look good.  Groundwater recharge should be factored into redevelopment. New development should have landscapes that collect water to help create sustainable water storage. Basins should have their supply refreshed by rain and runoff. This can be accomplished in part by incorporating new parking lot designs and directing runoff differently to a landscaped area that can naturally filter water and allow it to percolate into the ground. There should be a target for quantifying recharge. Some of these stormwater capture elements are included in the City of Corona’s General Plan Update.

The team posed the following questions for discussion: 1) Are you aware of undesirable results that have occurred in the past? 2) Are there specific undesirable results you are concerned about?  Nitrate levels in basin groundwater have been rising recently and total dissolved solid levels might be dropping.
 Trichloropropane (TCP) and Per- and polyfluoroalkyl substances (PFAS) are contaminants of concern that have had undesirable results for the Temescal Basin. TCP and PFAS, along with total dissolved solids and nitrate, could potentially impact groundwater use.  The more refined analytical technologies become, the more contaminants are found at smaller concentrations. There are contaminants that may exist in the water that are not currently known, and they may create future issues that we are not yet aware of. There should be some acknowledgement that unregulated contaminants today may be regulated in the future. The allowable limit for PFAS has changed drastically since it first started being regulated.  PFAS and other contaminants are concerning for future groundwater uses. Groundwater will not be a sustainable water source if contaminants make it unusable.  There has been pressure at the state level for regulating PFAS and it would be proactive to get ahead of the issue.

7. Public Comment
No members of the public provided comment.

8. Next Steps and Wrap Up
Isaacson summarized next steps for the consultant team and TAC members. The consultant team will prepare an internal draft of the Water Budget Chapter and continue conducting the numerical model analysis and developing the sustainability criteria. The consultant team distributed the Draft Hydrogeologic Conceptual Model and Groundwater Conditions Chapters to the TAC on November 17, 2020 and asked members to provide comments by December 4, 2020. Additional next steps are preparing for the upcoming public workshop, which will be held in Spring 2021 and the next TAC meeting on February 17, 2021.

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Discussion/Q&A
There were no questions or comments from the TAC members for this agenda item.

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Appendix A
Meeting Agenda

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Temescal GSP
Technical Advisory Committee Meeting 2
November 18, 2020
1:00 – 3:00 p.m.

Zoom Meeting: https://zoom.us/j/97160500385
Agenda
1) Welcome and Introductions
2) Overview of Meeting Agenda
3) Public Workshop 1
• Attendance and Engagement
• Input and Feedback
• Timeline and Focus for Public Workshop 2
• Discussion/Q&A
4) Draft GSP Chapters
• Hydrogeologic Conceptual Model
• Groundwater Conditions
• Discussion/Q&A
5) Input on Beneficial Uses
6) Draft Sustainability Goal and Conceptual Sustainability Criteria • Purpose of Sustainability Goal
• Draft Goal, Presentation
• Definition of Undesirable Results, Minimum Thresholds, and Measurable Objectives • Discussion of Draft Goal and Conceptual Undesirable Results for Consideration for Sustainability Indicators
7) Public Comment
8) Next Steps and Wrap Up
A-1

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Appendix B
Presentation Slides

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Technical Advisory Committee
Temescal Groundwater Sustainability Agency
November 18, 2020
Welcome and Introductions
B-1

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Zoom Controls:

Mute, Start/Stop Video, and Select Best
View
Tips for a Productive Discussion
• Let one person speak at a time
• Help make sure everyone gets equal time to give input • Keep your input concise so others have time to participate • Actively listen to others and seek to understand their perspectives
• Offer ideas to address questions and concerns raised by others B-2

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Overview of Meeting Agenda
Meeting Agenda

1. Welcome and Introductions

2. Overview of Meeting Agenda

3. Public Workshop 1

4. Draft GSP Chapters

5. Input on Beneficial Uses

6. Draft Sustainability Goal and
Conceptual Sustainability Criteria

7. Public Comment

8. Next Steps and Final Comments
B-3

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Public Workshop 1
Public Workshop 1
Attendance and Engagement
• 13 Participants on Zoom
• 452 Facebook Engagements
• 23 YouTube Views (as of 11/6)
B-4

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Public Workshop 1 ‐ Input and Feedback
Questions:
• Why might water taste bad?
• How is water cleaned?
• Why does water taste different in different areas?
Comments:
• Coordination with Chino, Riverside‐Arlington, and Orange County Water District important • Wetland behind Prado Dam has interconnected surface water and groundwater dependent ecosystems Feedback on outreach and involvement: • Send out questions or topics for discussion ahead of the workshops • Make announcements at pertinent Santa Ana Watershed Project Authority task forces • Good use of background slides, good presenters, and keeping things concise Public Workshop 2
B-5

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Discussion / Q&A
Draft GSP Chapters:

Hydrogeologic Conceptual Model
and
Groundwater Conditions
B-6

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The Temescal Basin
• DWR categorized as a Medium
Priority Basin
• Contiguous and connected
Where are we now in GSP process?
• HCM establishes physical framework of the groundwater basin • GW Conditions chapter documents historical and current status • Water Budget will quantify inflows, outflows and storage change • Numerical Model will support understanding of how the groundwater system works and provide the key analytical tool to evaluate:
• Sustainability Criteria
• Monitoring
• Projects and management actions
B-7

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Hydrogeologic Conceptual Model
Highlights
Surficial Geology
• Temescal Basin is primarily young
unconsolidated deposits
• Older bedrock surrounds the Basin
on the west and much of the east
• Faulting affects groundwater in
much of the Basin
B-8

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Cross Sections
• Three cross sections
• Illustrate subsurface conditions
• Relationship between aquifers in the
Temescal Basin
Cross Section A
• Channel Aquifer is
the principal
aquifer
• Alluvial and
Sandstone aquifers
secondary
B-9

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Channel Aquifer
• Channel Aquifer not present
everywhere
• The most productive wells (highest
hydraulic conductivity) in the
Temescal Basin are in the Channel
Aquifer
Temescal Basin
Thickness
• Deepest in the southwest
• Shallower in the area of the Channel
Aquifer
• Deepens near the Arlington Gap
B-10

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Groundwater Conditions Highlights
Groundwater Elevation
Contours
• Flow in the Temescal Basin is
towards the northwest, turning to
the west in Prado
• Groundwater flow direction
generally consistent
B-11

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Historical Groundwater Elevations
• Highest water levels in most
wells measured in early
1980s
• Lowest levels generally in
periods of dry conditions
and increased pumping
• Most hydrographs show
low water levels during
2000 to 2004, from
increased pumping
• Current levels are near
record lows
Corona Well 15
Water Quality
• Available groundwater quality data
reviewed
• Primary constituents of concern in
the Temescal Basin are total
dissolved solids and nitrate
• Total dissolved solids (TDS) elevated
in the productive portion of the
Basin
• Nitrate also high in some areas
B-12

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Interconnected Surface
Water
• First phase of surface water
groundwater evaluation
• Combined review of depth to
water, aerial imagery, conceptual
model, and mapped features
• There are areas of interconnected
surface water in the Basin
• Also areas where there are
groundwater dependent ecosystems
(GDEs) that will need to be addressed
Subsidence
• Basin‐wide vertical displacement
estimates from satellite
measurements
• No evidence of ground surface
change in these measurements
B-13

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Discussion / Q&A
Input on Beneficial Uses
B-14

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Known Beneficial Uses
• Municipal water supply
• Industrial water supply
• Rural residential water supply
• Small community water system water supply
• Small commercial water supply
• Groundwater dependent ecosystems in Temescal Wash and Prado Sustainability Goal and Criteria
B-15

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Draft Sustainability Goal
To sustain groundwater resources for the current and future beneficial uses of the Temescal Basin in a manner that is adaptive and responsive to the following objectives:
• Provide a long‐term, reliable and efficient groundwater supply for municipal, industrial, and other uses
• Provide reliable storage for water supply resilience during droughts and shortages
• Protect groundwater quality
• Support beneficial uses of interconnected surface waters, and • Support integrated and cooperative water resource management.

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Undesirable Results, Minimum Thresholds,
and Measurable Objectives
Undesirable Result – significant and unreasonable conditions for any of the six sustainability indicators
Minimum Threshold (MT) – numeric value used to define undesirable results for each sustainability indicator
Measurable Objective (MO) – specific, quantifiable goal to track the performance of sustainable management
Sustainability Criteria Considerations
for Temescal Basin
B-17

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Subsidence
• Subsidence is lowered ground surface resulting from collapse of subsurface materials, commonly related to pumping and
dewatering fine grained units
• Not a known issue and undesirable results not reported • But potential exists for undesirable results
Reduction in drainage capacity; drainage problems
Impacts on grade of facilities, e.g. pipelines, roads, runways Subsidence around a wellhead, e.g., casing collapse
Non‐recoverable loss of storage capacity in the aquifers Interconnected Surface Water
For Stream Flow
Depletion:

Stream Bed
Elevation
For Riparian
Vegetation:

About 20 to
30 feet
Coast Live
Oak
Red
Willow
California
Sycamore
Common
Elderberry Mule
Fat
Scalebroom
B-18

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Reduction of Groundwater Storage
• Storage is connected to water levels and the intent is to make sure there is enough water to meet the needs of the beneficial uses and users
• GSP regulations allow use of groundwater level MTs and MOs as a proxy, provided that the GSP demonstrate a correlation between groundwater levels and storage
Groundwater Levels
What undesirable effects do we want to
avoid?
• Impacts to shallow wells?
• Maintenance of municipal and
industrial water supply?
• Other?
Operable
Range of
Water Levels
B-19

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Water Quality
• Numeric value used to define significant and unreasonable degraded water quality throughout the basin
• In setting MTs for degraded water quality, GSAs shall consider local, state, and federal water quality standards applicable to the basin • Basin Plan and Maximum Concentration Limits
• 10 mg/L Nitrate as N (both)
• 770 mg/L TDS (basin plan) and 500 mg/L (MCL)
Discussion / Q&A
• Are you aware of undesirable results that have occurred in the past? • Are there specific undesirable results you are concerned about? • Comments on the Sustainability Goal:

To sustain groundwater resources for the current and future beneficial uses of the Temescal Basin in a manner that is adaptive and responsive to the following objectives:
• Provide a long‐term, reliable and efficient groundwater supply for municipal, industrial, and other uses • Provide reliable storage for water supply resilience during droughts and shortages • Protect groundwater quality
• Support beneficial uses of interconnected surface waters, and • Support integrated and cooperative water resource management.

B-20

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Public Comment
How to Raise Your Hand– Step 1
B-21

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How to Raise Your Hand – Step 2
Next Steps and Final Comments
B-22

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Next Steps
• Continue Technical Analyses
• Prepare internal draft Water Budget chapter of the GSP • Continue numerical model analysis
• Continue sustainability criteria development
• Administrative Draft HCM and GW Conditions chapters of the GSP provided to TAC November 17th, all comments back by December 4th. • Prepare for and hold Public Workshop 2 (date TBD)
• Next TAC meeting February 17, 2021
• Update on technical analyses
• Present sustainability criteria
Thank You!
B-23

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Technical Advisory Committee Meeting 3
Meeting Summary
Wednesday, February 17, 2020
1:00 p.m. – 3:00 p.m.

Location: Zoom Virtual Meeting
Attendees
Technical Advisory Committee Members
• Ava Moussavi, Riverside County Flood Control and Water Conservation District • Chad Blais, City of Norco Public Works Department
• Eric Lindberg, California Regional Water Quality Control Board – Santa Ana Region • Jacque Casillas, Mayor, City of Corona
• Katie Hockett, City of Corona Department of Water and Power • Roberta Reed, 3M Industrial Mineral Products Division • Timothy Ballon, All American Asphalt
• Tom Moody, City of Corona Department of Water and Power • Wes Speake, Vice Mayor, City of Corona
Additional City of Corona Department of Water and Power Staff • Kristian Alfelor
• Melissa Estrada-Maravilla
Consultant Team
• Chad Taylor, Todd Groundwater
• Gus Yates, Todd Groundwater
• Maureen Reilly, Todd Groundwater
• Alyson Scurlock, Kearns & West
• Jack Hughes, Kearns & West
• Joan Isaacson, Kearns & West
Summary

1. Welcome and Introductions
Joan Isaacson, facilitator from Kearns & West, welcomed all to the third meeting of the Temescal Groundwater Sustainability Agency (Temescal GSA) Technical Advisory Committee (TAC). She led roundtable introductions for TAC members and the consultants assisting the Temescal GSA with meeting facilitation and preparation of the Temescal Groundwater Sustainability Plan (Temescal GSP).

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2. Overview of Meeting Agenda
Isaacson reviewed the meeting agenda (see Appendix A). The focus was providing an update on the status of the Temescal GSP, presenting the draft sustainability criteria and getting input from TAC members, and providing an overview of Public Workshop 2.

3. Temescal GSP Status
Chad Taylor, Principal Hydrogeologist at Todd Groundwater, provided a status update on the Temescal GSP. The Hydrogeologic Conceptual Model and Groundwater Conditions chapters are now complete and posted to the Temescal GSA website for the public to access. The Numerical Model, which is used to calculate the water budget, and the Water Budget chapter, are underway and will include forecast modeling for growth and climate change.

Taylor described coordination meetings that have taken place with GSA representatives of neighboring basins, including the Orange County Water District, Chino Basin Watermaster, and Western Municipal Water District. All are willing to share information and data and are interested in reviewing documents as they become available. Todd Groundwater will continue to coordinate with stakeholders in neighboring basins, especially with the Western Municipal Water District and Chino Basin Watermaster to ensure the water budget for the Temescal Basin is similar to the ones they have prepared. For more information on the Temescal GSP Status, see pages 4 through 5 in Appendix B.

Discussion/Q&A
There were no questions or comments from the TAC members for this agenda item.

4. Draft Sustainability Criteria Presentation and Discussion Before presenting the draft sustainability criteria for the Temescal Basin, Taylor reviewed the following sustainability goal that was presented at the last TAC meeting on November 18, 2020:

To sustain groundwater resources for the current and future beneficial uses of the Temescal Basin in a manner that is adaptive and responsive to the following objectives:
• Provide a long-term, reliable, and efficient groundwater supply for municipal, industrial, and other uses;
• Provide reliable storage for water supply resilience during droughts and shortages; • Protect groundwater quality;
• Support beneficial uses of interconnected surface waters; and • Support integrated and cooperative water resource management.

Taylor explained that according to the Sustainable Groundwater Management Act, there are six sustainability indicators for which they must develop criteria. The six indicators include chronic lowering of groundwater levels, reduction of groundwater storage, degradation of water quality, land subsidence affecting land uses, depletions of interconnected surface water affecting beneficial uses, and seawater intrusion. Seawater intrusion is not applicable in the inland Temescal Basin. The five applicable indicators will be evaluated for the Temescal Basin.

Next, Taylor explained the factors relating to and defining sustainability that will be developed for each sustainability indicator. These include undesirable results, minimum thresholds, and measurable objectives. Undesirable results are significant and unreasonable conditions for any of the six sustainability indicators. Minimum thresholds are numeric values used to define undesirable results.

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Measurable objectives are specific, quantifiable goals used to track the performance of sustainable management. Lastly, he recapped the known beneficial uses in the Temescal Basin that were discussed by TAC members at the previous meeting. See pages 6 through 23 in Appendix B for more information on the draft sustainability criteria.

Chronic Lowering of Groundwater Levels
Taylor presented the sustainability criteria for chronic lowering of groundwater levels. Undesirable results for this indicator can occur progressively as water levels fall. These results can include increased pumping costs/decreased pump output, entrained air and/or broken suction on pumps, exposed screens, cascading water in the well, increased clogging of screens and/or accelerated corrosion, reduced saturated aquifer thickness, and reduced aquifer capacity. Taylor explained that the minimum threshold for defining undesirable results relative to chronic lowering of groundwater levels is defined at each key well by the historic minimum static groundwater elevation (or maximum historical depth to groundwater). Undesirable results are indicated when exceedances occur in measurements from two consecutive quarters in each of two consecutive years, in two-thirds or more of the key wells.

Taylor displayed the table of key wells, which are a subset of the current water level monitoring wells with representative records that continue to be monitored. The key wells table includes wells in the principal channel aquifer and secondary aquifers and wells that have been monitored a long time. Most wells have had historic maximum depths to groundwater within the last 10 years and the pump intake depth for most wells is below the historic depth to water. Taylor reviewed the measurable objective to maintain groundwater levels above the historic maximum depth to water, which maintains groundwater levels within the historical operating range. In summary, the water level conditions are currently sustainable and historic static lows will be used as the minimum threshold; the objective is to be above historical static lows.

Discussion/Q&A
The team opened the floor for questions and discussion. Discussion, comments, and questions are summarized below.
• Having visuals to accompany the data would be helpful. • Seeing how long the wells have been operational is good, but it would be nice to know how the differences between relate to the location of the wells. It seems shallower wells are closer to the river and deeper wells are farther away.

Reduction of Groundwater Storage
Taylor presented the sustainability criteria for reduction of groundwater storage, noting that storage is connected to water levels. He explained that GSP regulations allow the use of groundwater level minimum thresholds and measurable objectives as a proxy, and that the historic minimum-based water level threshold is well-suited for use as a proxy for groundwater storage. Undesirable results are defined as insufficient supply to support beneficial uses during droughts. Since groundwater storage is related to water levels, undesirable results are also associated with groundwater level declines.

Taylor explained the minimum threshold for groundwater storage, which is the same for groundwater levels. Using the historical minimum maintains the historical operational storage range in the principal channel aquifer and protects the most productive wells. The measurable objective for storage is also

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fulfilled by the measurable objective for groundwater levels, which maintains groundwater levels within the historical operating range. In summary, there is currently sufficient storage in the Temescal Basin and water level sustainability criteria will be used as a proxy for storage.

Discussion/Q&A
There were no questions or comments from the TAC members for this sustainability criteria.

Degradation of Water Quality
Maureen Reilly, Senior Engineer at Todd Groundwater, presented the sustainability criteria for degradation of water quality. She explained that the Temescal GSA is not responsible for local problems or degradation caused by others and that groundwater quality is under regulatory oversight by state agencies. However, the Temescal GSA is responsible for increased concentrations of water quality constituents due to groundwater management, such as through recharge and changes in pumping patterns relating to groundwater management. Undesirable results for this indicator will focus on total dissolved solids and nitrate, with other constituents being tracked as well. Total dissolved solids are both naturally occurring and anthropogenic. High nitrate concentrations in the Temescal Basin may be a result of previous agricultural or wastewater disposal. Because high concentrations of total dissolved solids and nitrate can limit beneficial uses, the main users of water either treat or blend groundwater.

To help inform measurable objectives, Reilly reviewed what other agencies in the basin are already doing. Water quality objectives have been defined in the Regional Water Quality Control Board Santa Ana Basin Plan and by the State of California in drinking water maximum contaminant levels. Nitrate levels have been set at 45 milligrams per liter (mg/L) and total dissolved solids levels have been set at 770 mg/L in the Regional Water Quality Control Board Santa Ana Basin Plan. She noted that total dissolved solids have a secondary maximum contaminant level for aesthetics which is 1,000 mg/L. Todd Groundwater looked at average concentrations in wells in the Temescal Basin before water entered the treatment process in the last 5 years. This showed 58 percent of wells exceeding the nitrate maximum contaminant levels and 33 percent exceeding the total dissolved solids secondary maximum contaminant level. Reilly explained that while concentrations at some wells exceed the maximum contaminant levels, all water delivered to end users meets all local, state, and federal standards.

Reilly described the minimum threshold for water quality as a statistically significant increase in the percentage of wells with 5-year averages exceeding the maximum contaminant level for total dissolved solids and/or nitrate, relative to current conditions. Statistically significant is defined as more than a 10 percent increase in the number of wells in a 5-year period. The measurable objective for total dissolved solids and nitrate is to maintain or reduce the percentage of wells with average concentrations exceeding the threshold based on conditions assessed in each 5-year Temescal GSP update. In summary, total dissolved solids and nitrate concentrations are elevated in some Temescal Basin wells, but all water delivered meets local, state, and federal drinking water standards through the use of treatment and blending facilities. The threshold is based on the number of currently affected wells.

Discussion/Q&A
The team opened the floor for questions and discussion. Discussion, comments, and questions are summarized below.
• The first question asked for confirmation of the water quality threshold being a change from the present, even though some wells currently exhibit issues. A consultant team member

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stated that current water quality constituents already exist, and the threshold is set to avoid any future degradation to water quality.
• Another question asked was whether the statistically significant change identified as 10 percent was based on any standards. A consultant team member explained that 10 percent is what other GSAs are using because anything less than 10 percent is typically within the natural variability of the data.
• TAC members discussed if maintaining current nitrate levels would be achievable without making any other changes in runoff and discharge from the surrounding areas. A consultant team member said that maintaining current levels could be compromised by legacy nitrate loading from historic agricultural uses. The nitrates flow slowly through the system and may not have reached groundwater or monitored wells yet. This will be important to monitor and report on in the 5-year Temescal GSP updates. A TAC member added that Corona has a desalination facility that assists in nitrate removal. The facility will help to improve water quality in the future, but it takes time. Nitrates are still being applied as part of fertilizers, but the nitrate fertilizer was more common when most of the basin’s agricultural activity was made up of orange groves. The small size and relatively shallow groundwater conditions in the Temescal Basin reduces the potential for legacy loading compared to other basins.

Land Subsidence Affecting Land Uses
Reilly presented the sustainability criteria for land subsidence affecting land uses and explained that when water is removed from the aquifer, fine-grain materials can compact and the ground surface can decline. Undesirable results for subsidence include damage to drainage channels; reduction in flood management capacity; damage to facilities; impacts on the grade of infrastructure such as pipelines, roads, and highways; damage to wellheads; casing failures; and non-recoverable loss of groundwater storage as fine-grained layers collapse. Subsidence in the Temescal Basin has been estimated by satellite via remote sensing using InSAR data provide by DWR going back to 2015. This method has a margin of error of approximately 0.1 feet. InSAR datasets estimate ground surface change in the Temescal Basin ranging between a rise of 0.08 feet to a fall of 0.08 which is very small and within the margin of error. She noted that none of these undesirable results have been observed in the Temescal Basin but that they will continue to be monitored over time.

Reilly presented the minimum threshold for subsidence, defined as a rate of decline equal to or greater than 0.2 feet in any 5-year period. This has been considered in terms of a cumulative decline equal to or greater than one foot of decline since 2015, which represents current conditions and aligns with the Sustainable Groundwater Management Act start date. The measurable objective is conceptually zero subsidence, while acknowledging measurement error and other uncertainties. In summary, there is no known current or historical subsidence in the Temescal Basin. The threshold is based on potential impacts to infrastructure using remotely sensed ground surface changes.

Discussion/Q&A
There were no questions or comments from the TAC members for this sustainability criteria.

Depletions of Interconnected Surface Water Affecting Beneficial Uses Gus Yates, Senior Hydrogeologist at Todd Groundwater, presented the sustainability criteria for depletions of interconnected surface water affecting beneficial uses. He explained that groundwater

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close to the surface can interact with vegetation or stream flows. Vegetation that relies on groundwater is referred to as phreatophytes and ecosystems that rely on groundwater are referred to as groundwater dependent ecosystems. Yates displayed a map showing the potential groundwater dependent ecosystems in the Temescal Basin and focused on the Prado Basin area. Depths in all wells around the Prado Basin and trends for groundwater levels, groundwater pumping, river flow, and rainfall were analyzed to determine if the Prado wetlands were supported by groundwater. The conclusion is that the Prado wetlands are more dependent on surface flows. Changes in surface inflows have much more influence than changes in groundwater pumping or levels to the north or south. More monitoring is needed in the southern Prado Basin and between Prado and central Temescal Basin pumping.

Yates explained the undesirable results for interconnected surface water. Declining groundwater levels in areas with riparian vegetation can reduce water availability to phreatophytic plant species, which are ones that extend roots to the water table and extract groundwater during the dry season when soil moisture is depleted. Another undesirable result is die-back, or mortality of Prado Basin vegetation. The minimum threshold for depletion of interconnected surface water is historical minimum water levels (maximum depth to water) in shallow monitoring wells in the southern Prado area, correlated with Temescal Basin pumping or water levels. The measurable objective for interconnected surface water is an amount of depletion that is less than the amount specified as the minimum threshold. Given that the objective is based on historical conditions, no specific rise in shallow groundwater levels or increase in stream flow is identified as providing a preferred set of groundwater dependent ecosystem conditions.

In summary, changes in surface inflows have much more influence than changes in groundwater pumping or levels to the north or south; additional monitoring in the southern Prado Basin is needed.

Discussion/Q&A
The team opened the floor for questions and discussion. Discussion, comments, and questions are summarized below.
• TAC members said the presentation of the sustainability criteria was great. • TAC members discussed the interplay of groundwater and surface water with the Prado wetlands. It was suggested that other stakeholders have interests in the health of the Prado wetlands and the surrounding water quality concerns. TAC members thought there was a lot of value in adding monitoring near the Prado wetlands to better understand the nearby groundwater practices.

5. Public Workshop 2
Jack Hughes, Kearns & West, provided an overview of the second public workshop on March 2, 2021 from 4:00-6:00 p.m. The public workshop will be held virtually on the Zoom platform and will be streamed on the City of Corona Facebook page, website, and on Corona TV. Spanish interpretation will be available for those in the Zoom meeting. The second public workshop will focus on the Hydrogeologic Conceptual Model, Groundwater Conditions, and Water Budget. Additionally, the project team is currently finalizing the second fact sheet. The second fact sheet will accompany the emails sent to interested parties and will be posted to the Temescal GSA website to provide the public an opportunity to learn about the topics prior to the workshop. Hughes invited TAC members to attend the second public workshop and to help spread the word to others who might be interested. See page 24 in Appendix B for more information.

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Discussion/Q&A
The team opened the floor for questions and discussion. Discussion, comments, and questions are summarized below.
• TAC members discussed the attendance at the first public workshop and ways to publicize the second workshop. About 13 people attended the first public workshop and additional participants connected via live streaming. The consultant team is finalizing the invitation materials for the second public workshop and will send them to TAC members for assistance with distribution.

6. Public Comment
No members of the public provided comment.

7. Next Steps and Wrap Up
Isaacson summarized next steps for the consultant team and TAC members. The consultant team will continue conducting the technical analyses, including the Water Budget calculations and Numerical Model analysis. The consultant team will also continue preparing the Sustainability Criteria Temescal GSP chapter and begin drafting the Monitoring Program Temescal GSP chapter. Additional next steps include the upcoming second public workshop, to be held on March 2, 2021, and the final TAC meeting on May 19, 2021. The final TAC meeting will focus on the Water Budget and Groundwater Model and include discussion of projects and management actions.

Discussion/Q&A
The team opened the floor for questions and discussion. Discussion, comments, and questions are summarized below.
• Review times for the Draft Sustainability Criteria Temescal GSP and Monitoring Program Temescal GSP chapters were discussed. TAC members should expect to receive the chapters to review in March.

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Appendix A
Meeting Agenda

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Temescal GSP
Technical Advisory Committee Meeting 3
February 17, 2020
1:00 – 3:00 p.m.

Zoom Meeting: https://zoom.us/j/96317714187
DRAFT Agenda
1) Welcome and Introductions
2) Overview of Meeting Agenda
3) Temescal GSP Status
• Hydrogeologic Conceptual Model and Groundwater Conditions Chapters • Coordination with Neighboring Basins
• Discussion/Q&A
4) Draft Sustainability Criteria Presentation and Q&A/Discussion • Sustainability Goal
• Beneficial Uses Recap
• Draft Sustainability Criteria
o Chronic Lowering of Groundwater Levels
o Reduction of Groundwater Storage
o Degradation of Water Quality
o Land Subsidence
o Depletions of Interconnected Surface Water
o Seawater Intrusion – Not applicable
5) Public Workshop 2
• Virtual Workshop, March 2, 2021, 4-6 p.m.
• Focused on Hydrogeologic Conceptual Model, Groundwater Conditions, and Water Budget • Discussion/Q&A
6) Public Comment
7) Next Steps and Wrap Up

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A-1
Appendix B
Presentation Slides

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Technical Advisory Committee
Temescal Groundwater Sustainability Agency
February 17, 2021
Welcome and Introductions
B-1

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Zoom Controls:

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Overview of Meeting Agenda
Meeting Agenda

1. Welcome and Introductions

2. Overview of Meeting Agenda

3. Temescal GSP Status

4. Draft Sustainability Criteria
Presentation and Discussion

5. Public Workshop 2

6. Public Comment

7. Next Steps and Wrap Up
B-3

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Temescal GSP Status
Where are we now in Temescal GSP process?
• Hydrogeologic Conceptual Model (HCM) and Groundwater Conditions chapters posted to GSA website
• Water Budget analyses and chapter and numerical model are underway
B-4

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Coordination with Neighboring Basins
• Consultant team and GSA meetings with neighboring groundwater basins:
• Orange County Water District
• Chino Basin Watermaster
• Arlington Basin GSA/Western Municipal Water District
• All willing to share information and data
• Coordination will continue
Discussion / Q&A
B-5

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Draft Sustainability Criteria
Sustainability Goal
To sustain groundwater resources for the current and future beneficial uses of the Temescal Basin in a manner that is adaptive and responsive to the following objectives:
• Provide a long‐term, reliable and efficient groundwater supply for municipal, industrial, and other uses
• Provide reliable storage for water supply resilience during droughts and shortages
• Protect groundwater quality
• Support beneficial uses of interconnected surface waters, and • Support integrated and cooperative water resource management.

B-6

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Sustainability Indicators
Chronic lowering of groundwater levels
Reduction of groundwater storage
Degradation of water quality
Depletions of interconnected surface water affecting beneficial uses Land subsidence affecting land uses
Seawater intrusion (not applicable here)
Undesirable Results, Minimum Thresholds,
and Measurable Objectives
Undesirable Result – significant and unreasonable conditions for any of the six sustainability indicators
Minimum Threshold (MT) – numeric value used to define undesirable results for each sustainability indicator
Measurable Objective (MO) – specific, quantifiable goal to track the performance of sustainable management
B-7

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Beneficial Uses from Last TAC Meeting
Undesirable Results ‐ Groundwater Levels
Groundwater level declines result in a
sequence of increasing undesirable results:

1. Increased pumping costs and a decrease
in pump output

2. Entrained air and or broken suction on
pumps

3. Exposed screens, cascading water in the
well, increased clogging of screens, and/or accelerated corrosion

4. Reduced saturated aquifer thickness and
reduced aquifer capacity
Groundwater Level
Groundwater Level
Operable
Range of
Water Levels
Well
Screens
B-8

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Minimum Threshold ‐ Groundwater Levels
The Minimum Threshold for defining undesirable results relative to chronic lowering of groundwater levels is defined at each Key Well by the historic minimum static groundwater elevation (maximum historical depth to groundwater)
Undesirable results are indicated when exceedances occur in measurements from two consecutive quarters in each of two consecutive years, in two‐thirds or more of the Key Wells Key Wells are a subset of the current water level monitoring wells with representative records that will continue to be monitored Local Well Name Earliest Monitoring Date
Average Depth to Groundwater
(ft bgs)
Pump Intake Depth
(ft bgs)
Date of Static Maximum Depth to
Groundwater
Maximum Static Depth to Groundwater
(ft MSL)
Corona 7A 6/1/2002 156.84 230 1/1/2003 178
Corona 8 12/13/2012 112.6 No Pump 5/4/2014 129.5
Corona 8A 1/1/1998 119.69 200 10/1/2001 169
Corona 9A 7/1/2002 80.72 220 7/1/2002 242
Corona 11 7/18/1959 134.14 180 9/13/2017 158
Corona 11A 12/6/2017 143.48 221.2 5/31/2014 155.2
Corona 12A 3/1/1993 158.59 280 11/2/2005 164
Corona 13 2/1/1977 141.19 182 6/1/1989 174
Corona 14 2/1/1924 184.92 250 5/1/2009 239
Corona 15 8/13/1952 116.63 180 12/1/2004 134
Corona 16 12/13/2012 140.3 No Pump 7/2/2018 159.5
Corona 17A 6/1/2002 110.63 180 5/13/2006 125
Corona 19 4/1/1992 102.73 200 9/1/2003 124.5
Corona 22 4/1/2001 150.19 370 5/1/2004 153.3
Corona 25 4/1/2001 61.71 180 7/1/2003 161.5
Corona 26 5/1/2001 136.86 333 10/1/2004 340.5
Corona 27 3/1/2003 154.19 436.7 3/3/2020 211
Corona 28 3/1/2003 90.59 170 9/6/2016 95.2
Corona 29 3/18/2009 88.63 230 8/1/2018 88.2
Corona 30 8/28/2009 56.9 No Pump 4/24/2014 70.6
Corona 31 3/18/2009 95.13 271 8/7/2009 132.2
Corona 33 3/13/2019 58.80 255 2/4/2020 68.1
Corona 10th/Lincoln 11/17/2011 197.5 No Pump 9/21/2013 204 Minimum Threshold ‐ Groundwater Levels
B-9

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Measurable Objective ‐ Groundwater Levels
The Measurable Objective is to maintain groundwater levels above the historical maximum depth to water (minimum groundwater elevation), equivalent to the Minimum Threshold.

This maintains groundwater levels within the historical operating range Summary/Questions/Comments –
Groundwater Levels
Summary:
• Water level conditions are currently sustainable
• Historical static lows will be used as the Minimum Threshold, and Objective is to be above historical static lows
B-10

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Reduction of Groundwater Storage
• Storage is connected to water levels
• GSP regulations allow use of groundwater level Minimum Thresholds and Measurable Objectives as a proxy
• Historical minimum‐based water level threshold is well suited to use as a proxy
Undesirable Results ‐ Groundwater Storage
• Insufficient supply to support
beneficial uses during droughts.
• Storage is related to groundwater
levels and undesirable results are
associated with groundwater level
declines.

Groundwater Level
Groundwater Level
Well
Screens
Groundwater Level
B-11

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Minimum Threshold ‐ Groundwater Storage
The Minimum Threshold for storage is fulfilled by the minimum threshold for groundwater levels
Groundwater level thresholds have been defined to reflect historical conditions, which is also protective of storage
Groundwater level thresholds and objectives are sufficiently protective to ensure prevention of significant and unreasonable results relating to storage
Measurable Objective ‐ Groundwater Storage
The Measurable Objective for storage is fulfilled by the Measurable Objective for groundwater levels, which maintain groundwater levels within the historical operating range.

B-12

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Summary/Questions/Comments –
Groundwater Storage
Summary:
• There is currently sufficient storage in the Temescal Basin • Water level criteria used as proxy for storage
Water Quality
The GSA is not responsible for local problems or degradation caused by others and groundwater quality is under regulatory oversight by State Agencies.

The GSA is responsible for increased concentrations in water quality due to management (recharge, pumping).

B-13

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Undesirable Result ‐ Water Quality
Focus will be on total dissolved solids (TDS) and
nitrate (other constituents will be tracked, too).

TDS is both naturally occurring and anthropogenic.

High nitrate concentrations in the Temescal Basin
may be a result of previous agricultural or
wastewater disposal (septic systems and other).

High concentrations of TDS and nitrate could limit
beneficial uses. The main users of water treat or
blend groundwater before use
(one form of treatment includes Reverse Osmosis
pictured here)
Minimum Threshold ‐ Water Quality
Beneficial uses of water and water quality objectives are defined in the RWQCB Santa Ana Basin Plan and by the State in drinking water maximum contaminant levels (MCLs). • Nitrate has a primary MCL for health concern whereas TDS has a secondary MCL for aesthetics.

Current ambient conditions (average concentrations in monitored wells between 2014 and 2019): • 58 Percent of wells exceed nitrate MCL • 33 Percent of wells exceed TDS Secondary MCL
While concentrations at some wells exceed the MCLs, all water delivered to end users meet all local, state, and federal standards.

RWQCB Basin Plan (mg/L) MCL (mg/L)
Nitrate (NO3) 45 45
TDS 770 1,000
B-14

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Threshold and Objective ‐ Water Quality
Minimum Threshold ‐ Statistically significant increase in the percentage of wells with averages exceeding the MCL for TDS and nitrate, relative to current conditions. Statistically significant is defined as more than 10 percent increase in number of wells in 5‐year period.

The Measurable Objective for nitrate and TDS is to maintain or reduce the percentage of wells with average concentrations exceeding the threshold, MCL, based on conditions assessed in each 5‐year Temescal GSP update
Summary/Questions/Comments – Water
Quality
Summary:
• TDS and nitrate concentrations are elevated in some Temescal Basin wells
• Treatment and blending facilitates municipal use – all water delivered meets local, state, and federal drinking water standards • Threshold is based on currently affected number of wells B-15

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Subsidence
Margin of error in
satellite
measurements is

0.1 ft
Undesirable Result ‐ Subsidence
Differential subsidence can affect:
• Drainage channels
• Reducing flood management capacity
• Damaging facilities
• Affecting the grade of infrastructure such as pipelines, roads, and highways • Damaging wellheads or causing casing failure
• Non‐recoverable loss of groundwater storage as fine‐grained layers collapse B-16

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Minimum Threshold ‐ Subsidence
The Minimum Threshold for subsidence is defined as a rate of decline equal to or greater than 0.2 feet in any five‐year period.

This has been considered in terms of a cumulative decline equal to or greater than one foot of decline since 2015.
2015 represents current conditions and the SGMA start date.

Measurable Objective ‐ Subsidence
The Measurable Objective is conceptually zero subsidence while acknowledging measurement error and other uncertainties.

B-17

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Summary/Questions/Comments –
Subsidence
Summary:
• No known current or historical subsidence in the Temescal Basin • Threshold based on potential impacts to infrastructure using remotely sensed ground surface changes
Interconnected Surface Water
For Stream Flow
Depletion:

Stream Bed
Elevation
For Riparian
Vegetation:

About 20 to
30 feet
Coast Live
Oak
Red
Willow
California
Sycamore
Common
Elderberry Mule
Fat
Scalebroom
B-18

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Temescal Basin
Groundwater
Dependent
Ecosystem(GDE)
Vegetation
Stream Channels
Natural
Lined
Possibly GDE Vegetation
Temescal Basin
Bedford-Coldwater Basin
Gage
WRF‐2
WRF‐1
Temescal Basin
Depth to
Groundwater
Evaluated depth to water in all
monitored wells (production and
monitoring)
Maximum depth less than 15
feet in northern Prado Basin
Minimum depth greater than 40
feet in Corona

CHINO DESALTER WELLS

CORONA WELLS
Maximum Butterfield Well
Depth to
Water <15 feet
Minimum
Depth to
Water >40 feet
B-19

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Temescal Basin Depth to Groundwater
0 50
100
150
200
Jan‐00
Dec‐01
Jan‐04
Dec‐05
Jan‐08Jan‐10Jan‐12Jan‐14Jan‐16Jan‐18Jan‐20
Depth below Ground Surface (feet)
Temescal Basin Depth to Groundwater
Well 7A Well 22 Well 17A Well 8A Butterfield

PRADO BASIN MAXIMUM DEPTH TO WATER

GROUND SURFACE
Butterfield Well
Factors Affecting
Prado Groundwater
Levels
Prado
Groundwater
Levels
North
South
Temescal
Groundwater Levels
Santa Ana River Flow
Rainfall
GW Pumping
B-20

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Interconnected Surface Water / Groundwater
Dependent Ecosystem (GDE) Conclusions:
• Prado wetlands were supported by groundwater prior to development.
• Now they are more dependent on surface inflows
• Changes in surface inflows have much more influence than changes in groundwater pumping or levels to the north or south
• More monitoring is needed in the southern Prado Basin and between Prado and southern Temescal Basin pumping
• This is a SGMA data gap that should be filled to protect the Temescal GSA Undesirable Result ‐ Interconnected Surface
Water / Groundwater Dependent Ecosystem
• Declining groundwater levels in areas with riparian vegetation can reduce water availability to phreatophytic plant species, which are ones that extend roots to the water table and extract groundwater during the dry season when soil moisture is depleted.
• Die‐back or mortality of Prado Basin vegetation
B-21

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Minimum Threshold ‐ Interconnected Surface
Water / Groundwater Dependent Ecosystem
The Minimum Threshold for depletion of interconnected
surface water is historical minimum water levels (maximum depth to water) in shallow monitoring wells in the southern Prado area, correlated with Temescal Basin pumping or water levels.

Measurable Objective ‐ Interconnected Surface
Water / Groundwater Dependent Ecosystem
The Measurable Objective for interconnected surface water is an amount of depletion that is less than the amount specified as the Minimum Threshold
Given that the objective is based on historical conditions, no specific rise in shallow groundwater levels or increase in stream flow is identified as providing a preferred set of GDE conditions
B-22

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Summary/Questions/Comments – Interconnected
Surface Water / Groundwater Dependent Ecosystem
Summary:
• Changes in surface inflows have much more influence than changes in groundwater pumping or levels to the north or south
• Additional monitoring in southern Prado is needed
Discussion / Q&A
B-23

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Public Workshop 2
Public Workshop 2
• March 2, 2021, 4 to 6 PM
• Focused on Hydrogeologic Conceptual Model, Groundwater Conditions, and Water Budget
• Fact Sheet No. 2 to accompany this workshop will be available soon • Virtual workshop link: (https://zoom.us/j/93530179115) • Please forward invite to interested parties
B-24

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Discussion / Q&A
Public Comment
B-25

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How to Raise Your Hand– Step 1
How to Raise Your Hand – Step 2
B-26

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Next Steps and Wrap Up
Next Steps
• Continue Technical Analyses • Continue Water Budget calculations • Continue numerical model analysis
• Prepare draft Sustainability Criteria Temescal GSP chapter • Begin work on Monitoring Program Temescal GSP chapter • Prepare for and hold Public Workshop 2 (March 2, 2021) • Zoom Link : https://zoom.us/j/93530179115 • Next TAC meeting May 19, 2021 • Water budget and groundwater model • Discussion of Projects and Management Actions
• Questions or comments to [email protected]
B-27

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Thank You!
B-28

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Technical Advisory Committee Meeting 4
Meeting Summary
Wednesday, June 16, 2021
1:00 p.m. – 3:00 p.m.

Location: Zoom Virtual Meeting
Attendees
Technical Advisory Committee Members
• Ava Moussavi, Riverside County Flood Control and Water Conservation District • Eric Lindberg, California Regional Water Quality Control Board – Santa Ana Region • Jacque Casillas, Mayor, City of Corona
• Katie Hockett, City of Corona Department of Water and Power • Roberta Reed, 3M Industrial Mineral Products Division • Tom Moody, City of Corona Department of Water and Power Additional City of Corona Department of Water and Power Staff • Kristian Alfelor
• Melissa Estrada-Maravilla
Consultant Team
• Chad Taylor, Todd Groundwater
• Gus Yates, Todd Groundwater
• Phyllis Stanin, Todd Groundwater
• Elisa Garvey, Carollo Engineers
• Inge Wiersema, Carollo Engineers
• Madison Rasmus, Carollo Engineers
• Alyson Scurlock, Kearns & West
• Jack Hughes, Kearns & West
• Joan Isaacson, Kearns & West
Summary

1. Welcome and Introductions
Joan Isaacson, facilitator from Kearns & West, welcomed all to the fourth meeting of the Temescal Groundwater Sustainability Agency (Temescal GSA) Technical Advisory Committee (TAC). She led roundtable introductions for TAC members and the consultants assisting the Temescal GSA with meeting facilitation and preparation of the Temescal Groundwater Sustainability Plan (Temescal GSP).

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2. Overview of Meeting Agenda
Isaacson reviewed the meeting agenda (see Appendix A). The focus of the meeting was providing an update on the status of the Temescal GSP and the water budget, presenting the draft projects and management actions and getting input from TAC members, and giving an overview of the third public workshop.

3. Temescal Groundwater Sustainability Plan Status
Chad Taylor, Principal Hydrogeologist at Todd Groundwater, provided a status update on the Temescal GSP. The Monitoring Network (Chapter 7), Projects and Management Actions (Chapter 8), Plan Implementation (Chapter 9), and Introduction (Chapter 1) chapters are currently in review by the Temescal GSA and will be distributed to the TAC for review in late June. The Water Budget (Chapter 5) and Sustainability Criteria (Chapter 6) chapters are in final review by the consultant team and will be distributed to the Temescal GSA in late June and to the TAC in early July. After receiving comments from the Temescal GSA and TAC on the remaining chapters, a draft of the Temescal GSP will be compiled and prepared for public release.

Taylor described the Temescal GSP review period and adoption process. The draft Temescal GSP will be posted in late July or early August and will have a 90-day public review period that will extend to October or November. The revised GSP is estimated to be ready for adoption by the Temescal GSA in November or December 2021 to meet the submittal deadline to the California Department of Water Resources (DWR) by January 31, 2022.

Taylor discussed the role of the TAC moving forward, which includes reviewing and providing comments on the draft chapters and inviting their constituents, communities, and any other interested parties to the upcoming third public workshop that will take place on July 8, 2021. He also asked the TAC to help spread the word when the draft of the Temescal GSP is posted for public review.

After the Temescal GSP is adopted, the TAC may be involved in the implementation phase; any future TAC meetings will be convened on an as-needed basis. The TAC will be informed of other Temescal GSP activities through routine notifications. For more information on the Temescal GSP Status, see pages 4 through 5 in Appendix B.

Discussion/Q&A
There were no questions or comments from the TAC members for this agenda item.

4. Water Budget Presentation
Gus Yates, Senior Hydrogeologist at Todd Groundwater, presented on the water budget, what it is, and how it is being developed. The water budget quantifies the inflows and outflows of the Temescal Basin over time in addition to the change in groundwater storage. Both inflows and outflows vary from year to year depending on hydrology and management. Yates described the process for estimating items in the water budget. Items that can be measured or calculated directly and thus serve as model inputs include dispersed recharge, wastewater percolation, groundwater pumping, and surface water inflows at the model boundary. Other items that are derived from model outputs are stream percolation, groundwater discharge to streams and the Prado Wetlands, subsurface boundary flows, and changes in storage.

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Yates reviewed dispersed recharge using a rainfall-runoff-recharge model diagram. He detailed the different ways in which water percolates through land including rainfall recharge, irrigated recharge, and runoff from impervious surfaces that can flow into pipes, the Prado Wetlands, or to pervious surfaces to become focused recharge. He noted that all percolation goes to the shallow groundwater zone, some of which becomes baseflow in streams. In the main part of the Temescal Basin, most deep percolation enters the regional aquifer system. Yates also reviewed a map of the 286 recharge polygons under evaluation, which the consultant team identified based on locations where recharge occurs and specific land uses that contribute to recharge. The recharge polygons extend east and west of the Temescal Basin to cover surface tributaries that drain into the basin. The model extends into the southern Chino Basin to characterize the interaction between basins and the Prado Wetlands.

Yates next described stream recharge in the Temescal Basin. He displayed the natural stream channels where percolation occurs and the cement-lined stream channels or pipelines where no percolation occurs that are included in the model. Stream channels in the Temescal Basin are far above the water table and the depth to groundwater decreases moving towards the northwest portion of the basin. In the Prado Wetlands area, the land surface and water table are close enough together that vegetation roots can reach the groundwater. Overall, percolation is not affected by groundwater levels except in the Prado Wetlands area.

Yates described subsurface inflow and outflow, which includes mountain-front recharge and percolation through fractures in the bedrock. The Temescal Basin was separated into four different zones and water budgets were developed for each. These water budget zones include the channel aquifer in the middle of the basin where most groundwater pumping occurs, the alluvial fan aquifer which makes up the remainder of the basin, the tributary watersheds which contribute inflows to the Temescal Basin, and the Chino Basin. Yates noted that groundwater pumping is concentrated in the channel aquifer.

Yates next discussed the water budget analysis periods that were selected. The Sustainable Groundwater Management Act (SGMA) requires three time periods be analyzed: historical, current, and future. For the historical time period, 1993-2007 was chosen, and for the current time period, 2010- 2013 was chosen; both time periods were chosen based on average climate conditions. The future time period is represented by 1993-2017 repeated twice since the required time period was 50 years. In addition, Yates discussed a graph showing the cumulative departure of rainfall, which is how the analysis periods were chosen, noting that there were much bigger wet and dry events in the 1993-2017 portion of graph.

Lastly, Yates presented the surface water and groundwater budgets. The surface water budget looks at inflows and outflows to surface waterways. Since creek channels are mostly concrete-lined and far above the water table in the Temescal Basin, there is little percolation, and the percolation rate is not affected by the groundwater level. The Prado Wetlands is the only area where groundwater and surface water interact. For the groundwater budget, Yates noted that quantitative results are still under review but that some general patterns are emerging. First, the largest sources of recharge in the Temescal Basin are reclaimed water percolation, followed by rain, irrigation, and pipe leaks, and stream percolation and subsurface inflow. Next, the yield of the channel aquifer depends on the inflow from the alluvial fan aquifer area; groundwater pumping is 60-75% of basin outflows. Lastly, the channel aquifer yields approximately the same amount as current pumping. Increasing pumping will not increase yield. For more information on the Water Budget (Chapter 5), see pages 6 through 12 in Appendix B.

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Discussion/Q&A
Isaacson opened the floor for questions and discussion. Discussion, comments, and questions are summarized below.
• The first question asked if the general patterns for recharge consider changes in land use over time. A consultant team member replied that the basin was mostly urbanized in the past as it is today.
• Another question asked if there was an estimate of how much of the area was developed and how much runoff increased with urbanization. A consultant team member explained that in the 1990s, about one-third to one-half of the basin was not urbanized and most development occurred in the 1990s and early 2000s. A TAC member added that there was a study conducted in the last few years that estimated a 6,000 acre-feet loss of recharge due to urbanization in the watershed.
• A TAC member asked about the relationship between cumulative deviation from the mean, production, and groundwater levels during the period where the Temescal Basin may be in overdraft. A consultant team member stated that the measured hydrographs are variable with some dating back to the 1990s where large declines in groundwater levels can be seen.

In the last 10 years, the level of urban development has been steady but in 2012, wastewater management changed slightly along with continued drought conditions, so there might have been a slight decline in the groundwater levels in wells. The decline in storage in the water budget seen to date is approximately 4 percent of the total outflow, which is within the margin of error for most water budget analyses. The future baseline scenario in the model will provide more information to confirm or disprove that and answer this question.

5. Draft Projects and Management Actions Presentation and Discussion Elisa Garvey, Engineer at Carollo Engineers, presented the draft projects and management actions for the Temescal GSP. She explained the three groupings of actions: baseline, planned, and potential future. Baseline refers to existing or established commitments to projects or actions. Planned actions are developed and evaluated projects or actions. Potential future actions describe projects or actions to be implemented later to achieve sustainability goals.

Garvey began by describing the baseline projects. The first is groundwater treatment at the Temescal Desalter to reduce nitrates, total suspended solids (TSS), total dissolved solids (TDS), and other contaminants of concern for the drinking water supply. The second project is water reclamation facility (WRF) percolation ponds that discharge from City of Corona-owned WRFs to percolation ponds that recharge the Temescal Basin. The third project includes water-level quality assurance and quality control activities that maintain the reliability of ongoing groundwater elevation data. The final project Garvey presented was the Western Riverside County Regional Authority (WRCRWA) plant that will soon produce recycled water for local irrigation use.

Garvey next reviewed the baseline management actions. These include Water Shortage Contingency Plans, which are plans that detail the stages of water shortage and conservation response based on a city’s available supply and deficit, and Water Conservation Programs, which include response actions to reduce water use in the stages of a water shortage. Additional management actions include the Western

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Municipal Water District Integrated Regional Water Management Plan, which is a coordinated, longrange regional water quantity and quality management strategy, and the Temescal GSA’s involvement in the Santa Ana Watershed Project, which is a coordinated management group formed to protect the Santa Ana River Basin and associated water resources.

Garvey then reviewed the three projects included in planned actions. First, the Potable Reuse Feasibility Study will look at the possible use of future reclaimed water supply. Second, the mountain runoff capture investigation would explore options for operational changes to allow for additional benefit of groundwater recharge using storm event runoff at the edges of the basin adjacent to the Santa Ana mountains that is collected in Riverside County Flood Control and Water Conservation District basins.

Lastly, the interconnected surface water monitoring wells project would include three shallow monitoring wells drilled into the Prado Management Area to allow for groundwater elevation monitoring.

Madison Rasmus, Environmental Engineer at Carollo Engineers, provided more information on the interconnected surface water monitoring wells project since its implementation date is within the first year of Temescal GSP adoption. Wells will be sited in the southern area of the Prado Management Area.

There is no active groundwater monitoring in this location so drilling wells will allow the Temescal GSA to better understand the relationship between the basin and interconnected water in the Prado Wetlands. The project will consist of three groundwater wells about 40-60 feet deep that will allow for continuous groundwater elevation data collection in the area. The data will be incorporated in the 5- year GSP update and monitoring wells will inform future management actions in the Santa Ana River Watershed.

Lastly, Garvey presented potential future actions. Data collected from the Prado Management Area monitoring wells will be used as part of monitoring for undesirable results to interconnected surface water in Prado. If this monitoring identifies potential undesirable results to interconnected surface water in the Prado Management Area, then coordination will be needed with upstream Santa Ana River partners as a management action. If groundwater levels in the Prado Management Area are falling, this approach will allow for coordinated solutions. There are two additional future management actions.

One is for future groundwater treatment, which would entail implementing advanced treatment for previously detected per- and polyfluoroalkyl substances (PFAS), TDS, nitrate, and trichloropropane (TCP). The other future management actions is for urban stormwater treatment, capture, and recharge, which is an exploration of urban stormwater harvesting to offset water supply and/or provide for groundwater recharge. For more information on the Projects and Management Actions (Chapter 8), see pages 13 through 16 in Appendix B.

Discussion/Q&A
There were no questions or comments from the TAC members for this agenda item.

6. Public Outreach
Jack Hughes, Senior Associate from Kearns & West, provided an overview of upcoming outreach and engagement activities. The third public workshop will be held virtually on July 8, 2021 from 4:00-6:00 p.m. on the Zoom platform. It will be streamed on the City of Corona Facebook page, website, and on Corona TV. Spanish interpretation will be available for those in the Zoom meeting. The third public workshop will focus on the sustainability criteria and projects and management actions. The third fact sheet will accompany the emails sent to interested parties. The fact sheet will also be posted to the Temescal GSP website to provide the public an opportunity to learn about the topics prior to the

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workshop. Hughes invited TAC members to attend the third public workshop and to help spread the word to others who might be interested.

In addition, the consultant team is preparing for a community leader meeting that will take place prior to the third public workshop to ensure the team is reaching a variety of stakeholders and hearing diverse interests. The purpose of the community leader meeting is to provide information on local water supply and learn about needs and perspectives in vulnerable communities. See pages 17 through 18 in Appendix B for more information.

Discussion/Q&A
There were no questions or comments from the TAC members for this agenda item.

7. Public Comment
No members of the public provided comment.

8. Next Steps and Wrap Up
Isaacson summarized next steps for the consultant team and TAC members. The consultant team will revise Chapters 1, 5, 6, 7, 8, and 9 based on GSA and TAC comments prior to compiling the complete GSP for public release. Additional next steps include the upcoming third public workshop on July 8, 2021 and preparation, finalization, adoption, and submittal of the GSP to DWR.

Discussion/Q&A
The team opened the floor for questions and discussion. Discussion, comments, and questions are summarized below.
• A TAC member expressed excitement for upcoming community leader engagement. • A TAC member thanked the TAC for providing valuable input throughout the GSP process.

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Appendix A
Meeting Agenda

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Temescal GSP
Technical Advisory Committee Meeting 4
June 16, 2021
1:00 – 3:00 p.m.

Zoom Meeting: https://zoom.us/j/99711646541
Agenda
1) Welcome and Introductions
2) Overview of Meeting Agenda
3) Temescal GSP Status
• Draft Chapters
• GSP Review and Adoption
• Technical Advisory Committee Look Ahead
• Discussion/Q&A
4) Water Budget Presentation
• Discussion/Q&A
5) Draft Projects and Management Actions Presentation and Discussion • Discussion/Q&A
• Are there other potential groundwater related projects we should consider? • Do you have ideas for how the volume of groundwater in the Basin could be increased? • Do you have ideas for making groundwater more sustainable in the Basin? 6) Public Outreach
• Virtual Workshop, July 8, 2021
• Community Leader Meeting
• Fact Sheet 3
• Discussion/Q&A
7) Public Comment
8) Next Steps and Wrap Up

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A-1
Appendix B
Presentation Slides

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Technical Advisory Committee
Temescal Groundwater Sustainability Agency
June 16, 2021
Welcome and Introductions
B-1

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Zoom Controls:

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Overview of Meeting Agenda
Meeting Agenda

1. Welcome and Introductions

2. Overview of Meeting Agenda

3. Temescal GSP Status

4. Water Budget Presentation

5. Draft Projects and Management
Actions Presentation and
Discussion

5. Public Outreach

6. Public Comment

7. Next Steps and Wrap Up
B-3

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Temescal GSP Status
Where are we in the Temescal GSP process?
• Monitoring Network (7), Projects and Management Actions (8), Plan Implementation (9), and Introduction (1) chapters in review by GSA now and will be distributed to TAC for review in the next two weeks • Water Budget (5) and Sustainability Criteria (6) chapters are in final review by the consultant team and will be distributed to the GSA later this week with TAC distribution in early July
• This represents all remaining chapters of the GSP
• After receiving comments from the GSA and TAC, the complete GSP will be compiled and prepared for public release
B-4

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GSP Review and Adoption Process
• The complete GSP will be posted for public review in late July/early August
• 90‐day public review period through October/November
• Revised GSP slated to be ready for GSA adoption
November/December 2021
• Submittal deadline to State Department of Water Resources January 31, 2022
Technical Advisory Committee Look‐Ahead
• Review chapters 1, 5, 6, 7, 8, and 9, deadline for comments will be transmitted with chapter distribution
• Spread the word about the upcoming GSP activities

1. Public workshop July 8th

2. Fact Sheet 3

3. Release of the complete GSP

4. Community leader meeting
• Future TAC meetings during GSP implementation
B-5

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Temescal Basin Water Budget
What is a Water Budget?
• A water budget quantifies the inflows and outflows of the Temescal Basin over time
• Both inflows and outflows vary from year to year, depending on hydrology or management
• Inflows ‐ Outflows = Change in Storage
B-6

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Preliminary Historical Groundwater Budgets
• Water budget items
• Measured or calculated; input to model
• Dispersed recharge
• Wastewater percolation
• Pumping
• Surface water inflows at model boundary
• Head‐dependent; ouput from model
• Stream percolation
• GW discharge to streams and Prado Wetlands
• Subsurface boundary flows
• Storage change
Connected
Impervious
Runoff
Disconnected
Impervious
Runoff
Water
Pipe
Leaks
Sewer
Pipe
Leaks
Rainfall
Irrigation
ET
Non-irrigated Irrigated
Municipal
Water and
Wastewater
Infiltration
Deep
Percolation

ROOT ZONE

SHALLOW GROUNDWATER ZONE

REGIONAL AQUIFER SYSTEM
Baseflow
Recharge
Direct
Runoff
Direct
Runoff
Dispersed
Recharge
Rainfall‐Runoff‐
Recharge Model
B-7

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Recharge Polygons
• 286 polygons, which have been identified
based on:
• Areas where recharge occurs
• Land uses that contribute to recharge
• Evolving land use
• Includes tributary watersheds
• Extends into southern Chino Basin
Stream Recharge
Stream Channel in Model
Natural bed
Cement-lined
or pipeline
B-8

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Stream
Recharge
Stream channels are
far above the water
table
Percolation not
affected by
groundwater level
except at Prado
Prado
Dam
Subsurface Inflow/Outflow
B-9

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Groundwater Pumping
Concentrated in Channel Aquifer
Water Budget Analysis Periods
• Three periods required by SGMA:
• “Historical” = water years 1993 to 2007
• “Current” = 2010 to 2013
• “Future” = 1993 to 2017 (repeated twice)
B-10

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Water Budget Analysis Periods
Surface Water Budget
• Large volumes of water pass through the basin
• Inflows = outflows. No storage change.
• Creek channels mostly concrete‐lined  little percolation • Creek channels mostly far above water table  percolation rate not affected by groundwater level
• Prado wetlands is only area where groundwater and surface water interact
B-11

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Groundwater Budget
• Quantitative results still under review
• General patterns:
• Sources of recharge in descending order:
• reclaimed water percolation,
• Rain, irrigation, and pipe leaks
• stream percolation, subsurface inflow
• Yield of channel aquifer depends on inflow from alluvial fan aquifer area • Pumping is 60‐75% of Basin outflow
• Channel aquifer yield approximately current pumping. Increasing pumping will not increase yield.

Discussion / Q&A
• What do you think the future of groundwater supply and demand will look like?
B-12

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Draft Projects and Management
Actions
Project Management/Action Groupings
Group 1 Baseline
Actions
Existing or
established
commitments to
projects/ actions
Group 2 Planned
Actions
Developed and
evaluated projects/
actions
Group 3 Potential
Future Actions
Potential projects/
actions to achieve
sustainability goals
B-13

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Group 1 Projects/ Management Actions
Description Involved Agencies Status
Groundwater Treatment: Treatment at the Temescal Desalter to reduce nitrates, TSS and TDS, and other contaminants of concern for the City’s drinking water supply.

City of Corona Ongoing
Water Reclamation Facility (WRF) Percolation Ponds: Discharge from City‐ owned WRFs to percolation ponds that recharge the Basin.

City of Corona Ongoing
Water Level QA/QC: Activities to maintain reliability of ongoing groundwater elevation data.

City of Corona Ongoing
Western Riverside County Regional Wastewater Authority (WRCRWA): This plant will soon produce recycled water for local irrigation use.

GSA, Jurupa CSD, and WMWD Pending coordination with WRCRWA and partner agencies
Water Shortage Contingency Plans: Stages of water shortage and conservation response based on a City’s available supply/deficit.

Cities of Corona and Norco Ongoing
Water Conservation Programs: Response actions to reduce water use in stages of water shortage.

Cities of Corona and Norco Ongoing
Western Municipal Water District IRWMP: Coordinated, long‐range regional water quantity and quality management strategy.
10 local cities/agencies including the
GSA
Ongoing
Santa Ana Watershed Involvement: Coordinated management group to protect the Santa Ana River basin and associated water resources.

GSA and Santa Ana Watershed Project
Authority (SAWPA) members
Ongoing t
Key
Project
Mgmt. Action
Group 2 Projects/ Management Actions
Description
Involved
Agencies Estimated Cost Status
Potable Reuse Feasibility Study: Study to look at use
potential for near to future reclaimed water supply.

GSA $150,000 to
$200,000
Study initiation
within second year
of GSP adoption.

Mountain Runoff Capture Investigation: Runoff during
storm events is collected into existing RCFCWCD basins
to mitigate flooding. This study would explore options
for operational changes to allow for additional benefit of groundwater recharge.

GSA and

RCFCWCD
$75,000 Study initiation
within five years of
GSP adoption.

Interconnected Surface Water Monitoring Wells
Implementation: Three shallow monitoring wells
drilled into the Prado Management Area (MA) to allow
for groundwater elevation monitoring.

GSA $40,000 to
$50,000
Implementation
within first year of
GSP adoption. t
Key
Project
Mgmt. Action
B-14

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Group 2 – Monitoring
Wells Project
Group 2 – Monitoring Wells Project
• 3 wells, 40‐60 feet deep
• Continuous groundwater
elevation data collection
• Data to be incorporated in
the 5‐year GSP update
• Monitoring wells will
inform future management
actions in the Santa Ana
River Watershed
B-15

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Group 3 Projects/Management Actions
Description Involved Agencies Status
Coordination with Upstream Santa Ana River Partners:

Contingent on Prado MA monitoring well installation. If groundwater levels in the MA are falling, this approach will entail coordination with upstream partners for solutions.

GSA and Santa Ana
Watershed Project
Authority (SAWPA)
members
No current anticipated
timeline.

Future Groundwater Treatment: Implementation of
advanced treatment to treat for previously detected PFAS as well as TDS, nitrate, and TCP.

GSA No current anticipated
timeline.

Urban Stormwater Treatment, Capture, and Recharge:

Exploration of urban stormwater harvesting to offset water supply and/or provide for groundwater recharge.

GSA No current anticipated
timeline. t
Key
Project
Mgmt. Action
Discussion / Q&A
• Are there other potential groundwater related projects we should consider?
• Do you have ideas for how the volume of groundwater in the Basin could be increased?
• Do you have ideas for making groundwater more sustainable in the Basin?
B-16

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Public Outreach
Public Workshop 3
• July 8, 2021, 4:00‐6:00 PM
• Fact Sheet 3
• Please invite others!
B-17

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Community Leader Meeting
• Provide information on local
water supply and learn
about needs and perspectives
in vulnerable communities
Discussion / Q&A
B-18

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Public Comment
How to Raise Your Hand– Step 1
B-19

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How to Raise Your Hand – Step 2
Next Steps and Wrap Up
B-20

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Next Steps
• Revise Chapters 1, 5, 6, 7, 8, and 9 based on GSA and TAC comments • Compile complete GSP for public release
• Prepare for and hold Public Workshop 3 (July 8, 2021) • Zoom Link : https://zoom.us/j/93530179115
• Prepare for GSP finalization, adoption, and submittal to DWR • Questions or comments to [email protected]
Thank You!
B-21

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Temescal Basin GSP

APPENDIX G
Summaries of Public Workshops and
Associated Fact Sheets

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Temescal Basin Public Workshop 1
Workshop Summary
October 2, 2020

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Contents

1. Background.......................................................................................................................3

2. Pre-Workshop Outreach .....................................................................................................3

3. When and Where ..............................................................................................................4

4. Attendance .......................................................................................................................4

5. Summary..........................................................................................................................4 Introduction to Groundwater .................................................................................................5 Introduction to the Sustainable Groundwater Management Act.................................................6 Introduction to the Temescal Basin ........................................................................................6 Groundwater Sustainability Plan Development.........................................................................7 Indicators for Sustainability ...................................................................................................7 How to Get Involved .............................................................................................................8

6. Wrap-up and Closing .........................................................................................................9

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1. Background
On September 16, 2014, the Governor of California signed into law a legislative package comprised of three bills: Assembly Bill (AB) 1739, Senate Bill (SB) 1168, and SB 1319. These laws are collectively known as the Sustainable Groundwater Management Act (SGMA). SGMA (pronounced sigma) defines sustainable groundwater management as the “management and use of groundwater in a manner that can be maintained without causing undesirable results.” This means keeping balanced levels of pumping and recharge of groundwater while assuring reliable water quality. SGMA provides a comprehensive framework for basin sustainability, additional technical analysis, and quantification of many aspects of basin sustainability and management. This includes extensive and detailed descriptions of the basin setting and conditions and more comprehensive monitoring of groundwater use, quality, and levels, including metering of groundwater usage.

SGMA requires the formation of a locally controlled Groundwater Sustainability Agency (GSA), which is responsible for developing and implementing a Groundwater Sustainability Plan (GSP). The GSP outlines how to achieve groundwater sustainability within 20 years of its adoption. The City of Corona, City of Norco, and Home Gardens County Water District have formed the Temescal Subbasin Groundwater Sustainability Agency (Temescal GSA) to create a GSP for the Temescal Basin.

GSAs must consider the interests of all beneficial uses and users of groundwater. The GSA must provide opportunities for public engagement and active involvement of diverse social, cultural, and economic elements of the population. The Temescal GSA recognizes that stakeholder and public engagement is critical to ensuring that the full range of interests of all beneficial uses and users of groundwater are represented during GSP development.

2. Pre-Workshop Outreach
The Temescal GSA used a variety of methods to inform stakeholders and community members about the workshop and encourage participation, as shown in the table on the next page.

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Table 1: Pre-Workshop Outreach Methods
Method Description
Website Workshop information was posted on the project website, hosted by the City of Corona’s Department of Water and Power, and was included in a calendar post.

The City of Norco and Home Gardens County Water District posted workshop information on their websites.

Social Media
Posts
The City of Corona posted information about the workshop through a Facebook Event and on its Instagram and Twitter accounts.

The City of Norco posted on its Facebook page.

Newsletters The City of Corona advertised the workshop in its Inner Circle newsletter, which is accessible online and distributed via email.

Emails Invitation emails were sent to those on the interested parties list.

Phone calls Phone calls were made to community groups and stakeholder organizations to make them aware that the GSP was being prepared and to invite them to the public workshop.

3. When and Where
The workshop was held on September 29, 2020 from 4:00 to 5:30 p.m.

The workshop was held virtually on the Zoom platform. People also had the option to view and participate from the City of Corona Council Chambers. The workshop was streamed on the City of Corona’s website, Facebook, and YouTube channels and on Corona TV, viewable on Channel 29 on Time Warner Spectrum and Channel 99 on AT&T.

4. Attendance and Social Media Views
Fifteen participants joined the Zoom meeting. Others viewed workshop on Facebook Live, YouTube, and Corona TV. Post-workshop statistics showed seventeen views on Youtube.

5. Summary
Welcome and Introductions
Jack Hughes, facilitator from Kearns & West, welcomed everyone to the first public workshop for the Temescal GSP. Christian Mendez from Kearns & West gave instructions in Spanish for accessing Spanish interpretation on Zoom. To begin the workshop, participants answered the following poll questions:

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1. Where does the water in your tap come from?
a. Local rivers and lakes
b. Local groundwater
c. Imported surface water

2. How much water comes from nearby sources?
a. 0 to 20 percent
b. 20 to 40 percent
c. 40 to 60 percent
d. 60 to 100 percent
After workshop participants responded to the poll, Chad Taylor, Senior Hydrogeologist at Todd Groundwater, discussed the answers. The water supply for Corona and Norco comes from local groundwater and is also imported. About half of the water delivered to Corona, Norco, and Home Gardens is imported and the rest comes from local groundwater sources. Next, participants watched a short video that showed how the City of Corona treats the groundwater it pumps at the Temescal Desalter and the Corona Ion Exchange Treatment Plant.

Hughes then invited the attendees to make introductions. Melissa Estrada-Maravilla, City of Corona Department of Water and Power Operations Analyst, introduced herself and thanked all for attending.

Taylor then introduced the consultant team from Todd Groundwater, Carollo Engineers, and Kearns & West. Hughes next invited the attending stakeholders to introduce themselves in the Zoom chat and thanked them for being there as it is important to involve the many diverse communities and stakeholders of Corona, Norco, and Home Gardens to create a strong GSP for the Temescal Basin.

Introduction to Groundwater
Taylor provided a general introduction to groundwater (presentation slides for this and the following sections can be viewed in Appendix A). In many places, water is present between grains of soil beneath the surface. When there is a lot of space between grains of soil, there can be significant groundwater, also known as a groundwater aquifer. In some areas, there are connections between water on the surface and groundwater. A large area of connected groundwater is called a groundwater basin. Wells are the most common way to access groundwater. Well are used to pump water for different uses such as for city or agricultural uses. Some wells are small and shallow, producing only a few gallons of water per minute, while other wells are large and deep, producing thousands of gallons of water per minute.

Taylor showed a cross-section of an aquifer and described how groundwater gets there. Water enters the ground by soaking into soils from rainfall, streams, lakes, or other surface water. There are unconfined and confined aquifers. Water can enter the upper aquifer, called the unconfined or water table aquifer, from the ground surface or stream. A confined aquifer, however, sits below a layer of impermeable material. Most of the water in the Temescal Basin is in an unconfined aquifer system.

Groundwater conditions change over time in response to increased pumping or decreased rainfall.

Water level declines can lead to problems with wells not having access to water for pumping and can also cause problems for interconnected surface water, such as potentially reducing flow in streams and affecting plants and animals that rely on water.

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Taylor discussed the importance of groundwater as a source of water in California. He compared the storage capacity of surface water reservoirs in California, totaling 50 million acre-feet of water, to a recent assessment of the storage capacity of groundwater basins. This capacity is estimated between 850 million and 1.3 billion acre-feet in the over 500 groundwater basins in California. Groundwater is important locally and statewide.

Discussion/Q&A
Hughes opened the floor for questions and comments. Participants were encouraged to answer the following questions: 1) What interests you about groundwater? and 2) Do you have questions or concerns about groundwater? Questions and comments from participants are summarized below. • How is water cleaned?
• Why might water taste bad?
• Why does water taste different in different areas?
• Education on water use is important.

Introduction to the Sustainable Groundwater Management Act Taylor presented the background and purpose of the SGMA. SGMA is California State legislation established in 2014 following a long period of state-wide drought. SGMA has altered how water is managed in California. It established requirements for state agencies to assess groundwater basin priorities and assign them as very low, low, medium, or high priority basins for sustainability planning.

The Department of Water Resources (DWR) has designated the Temescal Basin as medium priority basin. SGMA gives local agencies guidance for how to assess sustainability. There is the option for the state to intervene if local agencies are not acting, but that is a last resort. There is also financial assistance in the form of grants available from the state. The Temescal GSA, comprised of the City of Corona, the City of Norco, and Home Gardens County Water District, has received a grant for plan preparation.

Taylor explained that SGMA establishes requirements and specifies deadlines for achieving and maintaining groundwater sustainability. These requirements include forming a GSA and preparing a GSP to facilitate local groundwater management informed by stakeholders. SGMA requires that groundwater basins designated as medium or high priority form GSAs and file GSPs by January 31, 2022. They must then demonstrate sustainable groundwater management by 2042. GSPs outline how to achieve sustainability based on SGMA guidelines. This includes ongoing monitoring and management, annual reporting of groundwater conditions, and updates to the GSP every 5 years.

Introduction to the Temescal Basin
Taylor reviewed the Temescal Basin, which covers most of the City of Corona, about half of the City of Norco, and the western part of the Home Gardens County Water District. The Temescal Basin is bounded by the Chino Subbasin to the north, the Riverside-Arlington Subbasin to the east, the Bedford-Coldwater Subbasin to the south, and the Coastal Plain of Orange County on the west. The Temescal Basin and surrounding basins are one connected hydrologic area that has historically been managed together. DWR has designated the Temescal Basin as medium priority due to significant reliance on groundwater supplies.

Taylor described the organization of the Temescal GSA. The Temescal GSA provides for decisionmaking, technical support, and outreach to the community. The City of Corona, the City of Norco, and

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Home Gardens County Water District formed the Temescal GSA in 2017 through a memorandum of understanding. The City of Corona is leading the GSP effort with support from the Corona Department of Water and Power staff and additional consultants. The Technical Advisory Committee (TAC) provides input during GSP preparation, and TAC members communicate with other agencies and interested parties about GSP development. The GSP process is founded on public engagement and stakeholder outreach, which is the purpose of the public workshops.

Taylor explained that more information on the Temescal Basin and the Temescal GSP can be found in the Draft Plan Area Chapter that has been prepared. It is available for review on the Temescal GSA website (CoronaCA.gov/Groundwater). The Draft Plan Area Chapter includes the location of the Temescal Basin in relation to other basins and local hydrology, the public agencies with jurisdictional authority in the area, the general density of existing wells by type, and the current and historical land uses.

Groundwater Sustainability Plan Development
Taylor next provided a summary of the Temescal GSP workplan and schedule. Major Temescal GSP elements include data compilation; plan area; hydrogeologic conceptual model; groundwater model; sustainability goals and criteria; management actions, projects, and monitoring; and plan development.

Data compilation and a Draft Plan Area Chapter are already complete. The next steps are to develop the hydrogeological conceptual model, assess current and historical groundwater conditions, and construct a numerical groundwater model. These will be used to calculate groundwater budgets and sustainable yield, so it is known how much groundwater is available for use. After that comes creation of sustainability goals and criteria, which define sustainability in the Temescal Basin. Management actions to meet sustainability goals will then be identified, and a monitoring program will be established.

The Draft Temescal GSP will be made available for public review in Summer 2021 after completion of these steps. The final Temescal GSP will be completed by Fall 2021 prior to submittal to DWR.

Indicators for Sustainability
Taylor provided an overview of the six indicators for evaluating groundwater sustainability in a basin:
chronic lowering of groundwater levels, reduction of groundwater storage, degradation of water quality, depletion of interconnected surface water affecting beneficial uses, land subsidence affecting land uses, and seawater intrusion (not applicable in the Temescal Basin). Sustainability is defined as local management and use of groundwater in a way that can be maintained without experiencing undesirable results. Undesirable results will be determined for each of the criteria and minimum thresholds will be developed to avoid those results.

Taylor explained the process for achieving sustainability in the Temescal Basin. First, goals and thresholds will be set for each sustainability indicator in the Temescal GSP. Next, the implementation phase will occur, and a monitoring plan will be established. Monitoring will focus on assessing each indicator and will likely include measures for monitoring groundwater levels, water quality, and land subsidence. In addition, the Temescal GSA will undertake projects, such as ones that increase water supply availability, and management actions, such as reducing water use or demand. All components for achieving sustainability will be revisited every 5 years. Monitoring results will be used to refine the Temescal GSP to help better reflect local conditions and changes so that sustainability can be a dynamic long-term practice for the Temescal GSA and Temescal Basin.

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Discussion/Q&A
Hughes opened the floor for questions and discussion. Participants were encouraged to answer the following questions: 1) What water supply and quality goals are important to you? and 2) Is there information the project team should review?
• Are there more workshops scheduled?
• Can you share a bit about the efforts being taken to engage people and any future plans to engage the community in the plan?
• Orange County Water District (OCWD) thanks you for reaching out about the GSP process and will be submitting written comments. In 2017, OCWD submitted an alternative to a GSP for the Orange County Groundwater Basin that was approved in 2019. The Temescal Basin is adjacent to that basin, and coordination with Chino and our basin will be important in moving this item forward.
• OCWD owns and manages a large wetland and riparian habitat behind the Prado Dam. That area is dependent on interconnected surface water, so it will be important for the GSP to invest in groundwater dependent ecosystems.

How to Get Involved
Hughes explained how members of the public could be involved throughout GSP preparation, noting the importance of involving the many diverse communities and stakeholders of Corona, Norco, and Home Gardens to create a strong GSP for the Temescal Basin. There will be three public workshops, including the current one, to allow for people to get information about the GSP and give their feedback on its development. Prior to each workshop there will be several outreach methods to circulate information and boost attendance. These methods include emails, social media posts, and fact sheets. The next workshop will be held in winter of 2021 and will focus on sustainability criteria.

Another workshop focused on management actions will be held in the spring of 2021.

Hughes spoke about other opportunities to get information about GSP development and provide comment. In addition to the workshops, TAC meetings are open to the public. The public may listen in on those meetings and speak during the public comment portion. The project team will also be giving periodic updates at City Council and Board Meetings, which the public can also attend and comment on. This will be true as well for the Adoption Hearing for the final GSP. Before the Adoption Hearing, there will be a 90-day public comment period.

In addition to these opportunities, draft chapters and other materials will be posted on the project website hosted by the City of Corona Department of Water and Power: CoronaCA.gov/Groundwater.

The public can use the form on the website to make comments. Anyone who wants to be included on the mailing list should email [email protected]. People on the mailing list will receive updates on upcoming public workshops, meetings open to the public, and the availability of draft chapters for comment on the website.

Discussion/Q&A
Comments and questions are summarized below.
• It would be helpful to send out questions or topics for discussion ahead of the workshops to give people time to think about their responses.

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6. Wrap-up and Closing
Hughes thanked everyone for participating and encouraged people to sign up for updates on upcoming workshops by emailing [email protected] to be added to the mailing list. The next public workshop will be held in winter of 2021.

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Appendix A
Presentation Slides

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TEMESCAL GSP PUBLIC WORKSHOP 1
TEMESCAL GSP TALLER COMUNITARIO 1
About the GSP
The Sustainable Groundwater
Management Act or “SGMA” is a
California law that gives local agencies
new tools for managing groundwater
and planning for the future. The City of
Corona, City of Norco, and Home
Gardens County Water District have
formed the Temescal Groundwater
Sustainability Agency (Temescal GSA)
in order to make a Groundwater
Sustainability Plan for the Temescal
Basin. Since groundwater is such an
important resource for everyone, we
need your help!
Sobre el GSP
La Ley de Gestión Sostenible de Aguas
Subterráneas o “SGMA”, por sus siglas
en inglés, es una ley de California que
otorga a las agencias locales nuevas
herramientas para gestionar las aguas
subterráneas y planificar para el futuro.

La Ciudad de Corona, la Ciudad de
Norco y el Distrito Hídrico del Condado
de Home Gardens han formado la
Agencia de Sostenibilidad de
Aguas Subterráneas de la Cuenca
de Temescal (Temescal Groundwater
Sustainability Agency) o Temescal GSA
a fin de crear un Plan de
Sostenibilidad de Aguas
Subterráneas para la Cuenca de
Temescal. Dado que las aguas
subterráneas son un recurso muy
importante para todos, ¡necesitamos su
ayuda!

TEMESCAL GROUNDWATER

SUSTAINABLY PLAN
PUBLIC WORKSHOP 1

TEMESCAL GSP
TALLER COMUNITARIO 1
SEPTEMBER 29, 2020 / 29 DE SEPTIEMBRE DE 2020

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WELCOME

BIENVENIDOS
Interpretación española

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HOW TO USE ZOOM
CÓMO UTILIZAR ZOOM
To Select Best View
Para Seleccionar la Mejor Vista

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How to Rename Yourself – Step 1
Cómo Cambiar Su Nombre – Paso 1
How to Rename Yourself – Step 2
Cómo Cambiar Su Nombre – Paso 2

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WARM UP QUESTIONS

PREGUNTAS DE CALENTAMIENTO
»Where does the water in your tap come from?
» ¿De dónde viene el agua de tu grifo/llave?
a. Local rivers and lakes / Ríos o lagos locales
b. Local groundwater / Aguas subterráneas locales
c. Imported surface water / Agua superficial importada
» How much water comes from nearby sources?
» ¿Cuánta agua proviene de fuentes cercanas?
a. 0 to 20 percent / 0 a 20 por ciento
b. 20 to 40 percent / 20 a 40 por ciento
c. 40 to 60 percent / 40 a 60 por ciento
d. 60 to 100 percent / 60 a 100 por ciento

WORKSHOP PURPOSE
PROPÓSITO DEL TALLER
» Give information about groundwater
Dar información sobre las aguas subterráneas.
» Introduce Sustainable Groundwater Management Act, the Temescal Groundwater Sustainability Agency, the Temescal Basin, and Groundwater Sustainability Plans.

Introducir la Ley de Gestión Sostenible de las Aguas Subterráneas, la Agencia de Sostenibilidad de las Aguas Subterráneas Temescal y la Cuenca del Temescal.
» Learn about your groundwater interests and what is important for you for the future of groundwater in the Temescal Basin.

Conocer sus intereses sobre el agua subterránea y lo que es importante para usted para el futuro del agua subterránea en la Cuenca del Temescal. Page 2121 of 3451

INTRODUCTIONS

PRESENTACIONES

TIPS FOR A PRODUCTIVE DISCUSSION
CONSEJOS PARA UNA DISCUSIÓN

PRODUCTIVA
»One speaker at a time
Habla solo una persona la vez
»Keep input concise
Sea conciso
»Actively listen
Escuche activamente
»Offer solutions
Ofrezca soluciones

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YOUR INPUT MATTERS
SU OPINIÓN ES IMPORTANTE
» The planning team will consider your comments as
they prepare the Groundwater Sustainability Plan.

El equipo de planificación considerará sus
comentarios mientras prepara el Plan de
sostenibilidad de aguas subterráneas.
» Your input will be recorded, organized
thematically, and presented in a workshop
summary on the project website.

Su aportación será registrada, organizada
temáticamente y presentada en un resumen del
taller en el sitio web del proyecto.

INTRODUCTION TO

GROUNDWATER
INTRODUCCIÓN A LAS AGUAS
SUBTERRÁNEAS

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WHAT IS GROUNDWATER?
¿QUÉ SON LAS AGUAS SUBTERRÁNEAS?
HOW IS GROUNDWATER ACCESSED?
¿CÓMO SE ACCEDE A LAS AGUAS
SUBTERRÁNEAS?

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HOW DOES GROUNDWATER OCCUR?
¿CÓMO SURGEN LAS AGUAS SUBTERRÁNEAS?

GROUNDWATER IS IMPORTANT
LAS AGUAS SUBTERRÁNEAS SON IMPORTANTES

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DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS
»What interests you about groundwater?
¿Qué le interesa sobre las aguas subterráneas?
» Do you have questions or concerns about
groundwater?
¿Tiene dudas o preocupaciones sobre las aguas
subterráneas?
» What else?
¿Qué más?
How to Raise Your Hand– Step 1
Cómo Levantar la Mano – Paso 1

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How to Raise Your Hand – Step 2
Cómo Levantar la Mano – Paso 2
How to Mute and Start/Stop Video
Cómo Silenciar e Iniciar/Detener el Video

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WHAT IS THE SUSTAINABLE
GROUNDWATER MANAGEMENT ACT?
¿QUÉ ES LA LEY DE GESTIÓN

SOSTENIBLE DE LAS AGUAS
SUBTERRÁNEAS?

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SUSTAINABLE GROUNDWATER

MANAGEMENT ACT (SGMA)
Landmark legislation in 2014
» Recognizes that groundwater management in California
is best accomplished locally
» Includes State intervention if necessary
» State assistance is also available
Legislación histórica en 2014
» Reconoce que la gestión de las aguas subterráneas en
California se logra mejor a nivel local
» Incluye intervención estatal si es necesario
» La asistencia estatal también está disponible

SUSTAINABLE GROUNDWATER

MANAGEMENT ACT (SGMA)
Includes comprehensive requirements for:
» Forming groundwater sustainability agency (GSA)
» Preparing groundwater sustainability plan (GSP)
Incluye diversos requisitos para:
»Agencia de sostenibilidad de las aguas
subterráneas (GSA)
» Preparación de un plan de sostenibilidad de las
aguas subterráneas (GSP)

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SGMA HAS A REQUIRED TIMELINE

SGMA TIENE UN CRONOGRAMA REQUERIDO
2040/2042
Achieve and
demonstrate
sustainability
Lograr y
demostrar
sostenibilidad
Today INTRODUCTION TO THE TEMESCAL
BASIN
INTRODUCCIÓN A LA CUENCA DEL

TEMESCAL

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THE TEMESCAL BASIN

LA CUENCA DEL TEMESCAL
» DWR categorized as a
Medium Priority Basin
Catalogada por DWR
como Cuenca de
prioridad media
»Contiguous and
connected
Contigua y conectada
GSA ORGANIZATION / ORGANIZACÍON
Staff and Consultants
Personal y Consultores
• Corona DWP Staff
• Todd Groundwater
• Carollo Engineers
• Kearns & West
City of Corona
Technical Advisory Committee
Comité Asesor Técnico
• Public agencies/Agencias públicas
• Local businesses/Empresas locales
• Well owners/Propietarios de pozos
• Community interests/Intereses comunitarios
Other agencies and interested parties/Otras agencias y partes interesadas Department of Water and Power
Departamento de Aqua y Energía
City of Norco
Home Gardens
County Water District

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DRAFT PLAN AREA CHAPTER
ESQUEMA DEL ÁREA DEL PLAN
Description of Plan Area
Descripción del Área de Plan
» Jurisdictional boundaries
Limites jurisdiccionales
» Existing monitoring and management
Monitoreo y gestión existentes
»Well distribution
Distribución de pozos
» Land use designations and description
Designaciones y descripción del uso de
la tierra
PLAN AREA / ÁREA DEL PLAN

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GROUNDWATER SUSTAINABILITY PLAN

DEVELOPMENT

DESARROLLO DE PLAN DE

SOSTENIBILIDAD DE AGUAS
SUBTERRÁNEAS

GSP SCHEDULE

PROGRAMA DE GSP
2021
2020
Data Compilation /
Management System
Plan Area / Institutional
Setting
Hydrogeologic
Conceptual Model /
Groundwater Conditions
Groundwater Model /
Water Budgets
Sustainability Goals and
Criteria
Management Actions,
Projects, and Monitoring
Plan Development

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GSP SCHEDULE

PROGRAMA DE GSP
2021
2020
Recopilación de Datos /
Sistema de Gestión
Área del Plan / Marco
Institucional
Modelo Conceptual
Hidrogeológico /
Condiciones Aguas
Subterráneas
Modelo de Aguas
Subterráneas/
Presupuestos de Aguas
Criterios y Metas de
Sostenibilidad
Gestión de Acciones,
Proyectos y Monitoreo
Desarrollo de Plan
WHAT IS SUSTAINABILITY?
¿QUÉ ES LA SOSTENIBILIDAD?

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Chronic lowering of groundwater levels
Disminución crónica de los niveles de aguas subterráneas Reduction of groundwater storage
Reducción del almacenamiento de aguas subterráneas
Degradation of water quality
Degradación de la calidad del agua
Depletions of interconnected surface water affecting beneficial uses Agotamiento de las aguas superficiales interconectadas que afectan a los usos beneficiosos
Land subsidence affecting land uses
El hundimiento de la tierra que afecta a los usos de la tierra Seawater intrusion (not applicable here)
Intrusión de agua de mar (no aplicable aquí)

SUSTAINABILITY CRITERIA

CRITERIOS DE SOSTENIBILIDAD
Operable
Range of
Water Levels
/ Rango
operable de
niveles de
agua
EXAMPLE SUSTAINABILITY CRITERIA:

GROUNDWATER LEVELS
EJEMPLO DE CRITERIOS DE SOSTENIBILIDAD:

NIVELES DE AGUAS SUBTERRÁNEAS
What undesirable effects do we want to avoid?
» Impacts to shallow wells?
» Maintenance of municipal and industrial water
supply?
» Other?
¿Qué efectos indeseables queremos evitar?
» ¿Impactos en pozos poco profundos?
» ¿Mantenimiento del suministro de agua
municipal e industrial?
» ¿Otros?

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ACHIEVING SUSTAINABILITY

LOGRAR LA SOSTENIBILIDAD
Set Goals
Fijar Metas
For Sustainability Criteria /
Para Criterios de
Sostenibilidad
Sustainability
Sostenibilidad
Projects and Management
Actions / Gestión de
Proyectos y Acciones
Monitor
Observar
Assess Progress /
Evaluar el Progreso
Projects increase supply /
Proyectos para
aumentar reservas
Management Actions reduce
demand / Gestión de Acciones
para reducir la demanda

DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS
»What water supply and quality goals are
important to you?
¿Qué objetivos de suministro y calidad de agua
son importantes para usted?
» Is there information the project team
should review?
¿Hay información que el equipo del proyecto
debe revisar?
» What else?
¿Qué más? [email protected] Page 2136 of 3451
HOW CAN YOU GET INVOLVED?
¿CÓMO PUEDE INVOLUCRARSE?

PUBLIC WORKSHOPS
TALLERES PÚBLICOS
2021
2020
Data Compilation /
Management System
Plan Area / Institutional
Setting
Hydrogeologic
Conceptual Model /
Groundwater Conditions
Groundwater Model /
Water Budgets
Sustainability Goals and
Criteria
Management Actions,
Projects, and Monitoring
Plan Development
Public Workshop 1
Kickoff and Introduction to
SGMA
Public Workshop 2
Sustainability Criteria
Public Workshop 3
Management Actions
Draft GSP Presentation

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PUBLIC WORKSHOPS
TALLERES PÚBLICOS
2021
2020
Recopilación de Datos /
Sistema de Gestión
Área del Plan / Marco
Institucional
Modelo Conceptual
Hidrogeológico /
Condiciones Aguas
Subterráneas
Modelo de Aguas
Subterráneas/
Presupuestos de Aguas
Criterios y Metas de
Sostenibilidad
Gestión de Acciones,
Proyectos y Monitoreo
Desarrollo de Plan
Taller Comunitario 1
Inicio y Presentaciónde SGMA
Taller Comunitario 2
Criterios de Sostenibilidad
Taller Comunitario 3
Acciones de Gestión
Presentación Inicial de GSP

OTHER MEETINGS

OTRAS REUNIONES
» Technical Advisory Committee Meetings
Reuniones del Comité Asesor Técnico
»Updates at City Council and Board Meetings
Actualizaciones en las reuniones del consejo
y la junta de la ciudad
»Adoption Hearing for Final GSP
Audiencia de adopción del GSP final

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WEBSITE

SITIOS WEB

HOW TO KEEP IN TOUCH
CÓMO MANTENERSE EN CONTACTO
» Sign up for the mailing list by emailing
[email protected]
Regístrese en la lista de correo enviando un correo
electrónico a [email protected]
»Visit the website to view information, review draft
chapters and other materials, and to submit
comments : www.CoronaCA.gov/Groundwater
Visite el sitio web para ver información, revisar
borradores de capítulos y otros materiales, y enviar
comentarios: www.CoronaCA.gov/Groundwater

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THANK YOU

GRACIAS

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Temescal Basin Public Workshop 2
Workshop Summary

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Contents

1. Background ...............................................................................................................................1

2. Pre-Workshop Outreach .............................................................................................................1

3. When and Where.......................................................................................................................2

4. Attendance and Social Media Views.............................................................................................2

5. Summary...................................................................................................................................2 Review of Groundwater Sustainability Plan Development.......................................................2 Hydrogeologic Conceptual Model .........................................................................................3 Groundwater Conditions......................................................................................................4 Water Budget.....................................................................................................................5 How to Stay Involved..........................................................................................................6

6. Wrap Up and Closing..................................................................................................................6 Appendix
A. Presentation Slides

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SGMA requires the formation of a locally controlled Groundwater Sustainability Agency (GSA), which is responsible for developing and implementing a Groundwater Sustainability Plan (GSP). The GSP outlines how to achieve groundwater sustainability within 20 years of its adoption. The City of Corona, City of Norco, and Home Gardens County Water District have formed the Temescal Basin Groundwater Sustainability Agency (Temescal GSA) to create a GSP for the Temescal Basin.

To share information and get input from stakeholders and the public, the Temescal GSA is holding a series of public workshops. The first public workshop, conducted on September 29, 2020, focused on communicating basic information about SGMA, the Temescal Basin, GSP development, and what sustainability means in a GSP. The second public workshop, conducted on March 2, 2021, focused on providing updates on the Temescal GSP development and introducing the hydrogeologic conceptual model, groundwater conditions, and water budget. This summary documents the outreach methods, time and location, attendance, and major topics presented and discussed at the second public workshop.

2. Pre-Workshop Outreach
The Temescal GSA used a variety of methods to inform stakeholders and community members about the workshop and encourage participation, as shown in Table 1 on the next page.

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Social Media Posts The City of Corona posted information about the workshop through a Facebook Event.

The City of Norco posted on its Facebook page.

Newsletters The City of Corona advertised the workshop in its Inner Circle newsletter, which is accessible online and distributed via email.

Emails Invitation emails were sent to those on the interested parties list.

3. When and Where
The workshop was held on March 2, 2021 from 4:00 to 6:00 p.m.

The workshop was held virtually on the Zoom platform. The workshop was streamed on the City of Corona’s website, Facebook, and YouTube channels and on Corona TV, viewable on Channel 29 on Time Warner Spectrum and Channel 99 on AT&T.

4. Attendance and Social Media Views
Approximately 24 people attended the Zoom virtual meeting, including 10 stakeholder participants.

Others viewed the workshop on Facebook Live, YouTube, and Corona TV. Post-workshop statistics indicated 17 views on YouTube.

5. Summary
Welcome and Introductions
Jack Hughes, facilitator from Kearns & West, welcomed everyone to the second public workshop for the Temescal GSP. Christian Mendez from Kearns & West gave instructions in Spanish for accessing Spanish interpretation on Zoom. Hughes reviewed the workshop purpose, which was to provide Temescal GSP development updates and introduce the hydrogeologic conceptual model, groundwater conditions, and water budget. Additionally, the consultant team wanted to learn from participants what they thought the most important uses of groundwater were and if they know of any current or historical problems regarding the use of groundwater in the Temescal Basin.

Hughes invited the workshop attendees to make introductions using the Zoom chat and recognized the Temescal GSA representatives and elected officials in attendance. Hughes then introduced the additional workshop presenters: Chad Taylor, Principal Hydrogeologist at Todd Groundwater, and Maureen Reilly, Senior Engineer at Todd Groundwater.

Review of Groundwater Sustainability Plan Development
Taylor first presented the background and purpose of SGMA (see Appendix A for presentation slides for this and the following sections). The State can intervene if local agencies are not acting, but that is a

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last option. Under SGMA, local agencies are provided guidance for how to assess sustainability, tools for achieving or maintaining sustainability, and financial assistance in the form of grants available from the State. The Temescal GSA, comprised of the City of Corona, the City of Norco, and Home Gardens County Water District, has received a grant to prepare the GSP for the Temescal Basin.

Taylor explained that GSPs are detailed road maps for how groundwater basins will achieve or maintain long-term sustainability. Similar to other state planning requirements that agencies have been undertaking for many years, GSPs have periodic review processes and annual reporting requirements.

These include long-term planning components, such as 50-year simulations of future conditions, to ensure long-term sustainability can be maintained.

Taylor described the Temescal Basin area, which covers most of the City of Corona, about half of the City of Norco, and the western part of the Home Gardens County Water District. The Temescal Basin is bounded by the Chino Subbasin to the north, the Riverside-Arlington Subbasin to the east, the BedfordColdwater Subbasin to the south, and the Coastal Plain of Orange County on the west. One GSA, Temescal GSA, was formed for the Temescal Basin because the area is hydrologically connected and has historically been managed as one unit. The Department of Water Resources has designated the Temescal Basin as a medium priority basin, which required the Temescal GSA to prepare the Temescal GSP.

Taylor next described the organization of the Temescal GSA. The Temescal GSA provides for decisionmaking, technical support, and community outreach. The City of Corona, the City of Norco, and Home Gardens County Water District formed the Temescal GSA in 2017 through a memorandum of understanding. The City of Corona is leading the GSP effort with support from Corona Department of Water and Power staff and additional consultants. The Technical Advisory Committee provides input during GSP preparation, and Technical Advisory Committee members communicate with other agencies and interested parties about GSP development. The GSP process is founded on public engagement and stakeholder outreach, which is the purpose of the public workshops.

Participants then answered the following warm up question using a Zoom poll: How many major aquifers are there in the Temescal Basin?
• Two
• Three
• Five
• Ten
Taylor provided and discussed the answer once the poll was closed. There are two major aquifers in the Temescal Basin, depending on how a major aquifer is defined. The section below on the hydrogeologic conceptual model has more information on the aquifers in the basin.

Hydrogeologic Conceptual Model
Taylor presented the hydrogeologic conceptual model. The model is a summary description along with a series of maps and graphics that defines where groundwater is in the Temescal Basin, how it gets there, and how it moves. It considers what areas of the Temescal Basin are made up of coarse or fine materials and includes descriptions of basin boundaries, geology, aquifers and aquitards, aquifer properties, and groundwater use. The model is accompanied by maps and graphics that show

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topography, surface water features, geology, soils, aquifer locations, basin thickness, and crosssections.

Taylor reviewed the surficial geology and the location and characteristics of the channel aquifer in the Temescal Basin. The Temescal Basin in primarily made up of young, unconsolidated deposits surrounded by older bedrock on the western and eastern portions of the basin. There are also some older, partially consolidated deposits in the northern portion of the Temescal Basin. Faulting affects groundwater in much of the Temescal Basin and can restrict groundwater flow laterally. Taylor noted that the principal aquifer in the Temescal Basin is the channel aquifer. The channel aquifer is coarser grained and the more productive wells in the basin draw from the channel aquifer. As a result, most of the municipal supply wells are in the channel aquifer and it is an important component of the groundwater system.

Taylor presented one of the three cross-sections that have been prepared for the Temescal Basin that illustrate the underground conditions. Taylor reviewed the A to A’ cross-section that extends from the southwest to northeast. The cross-section starts in the Santa Ana mountains. Moving from southwest to northeast in the Temescal Basin, there are alluvial fan aquifers underlaid by sandstone aquifers, which are the secondary aquifers in the basin. Next is the channel aquifer that is adjacent to the Temescal Wash. The channel aquifer and Temescal Wash have similar deposits, so they are considered functionally similar and connected. They are underlaid by granitic bedrock, which is not very conducive to groundwater presence or flow. Many wells draw groundwater only from the channel aquifer, whereas some wells have screens below the channel aquifer. Lastly, Taylor presented a three-dimensional block diagram that shows the relationship between subsurface materials, ground surface, and basin activities in the Temescal Basin.

Discussion/Q&A
Hughes opened the floor for questions and comments. There were no questions or comments from participants after this presentation.

Groundwater Conditions
Taylor presented groundwater conditions in the Temescal Basin, which include current and historical conditions such as groundwater elevations, water quality, interconnected surface water, and subsidence. The Draft Hydrogeologic Conceptual Model and Groundwater Conditions chapters are available for review on the Temescal GSA website (CoronaCA.gov/Groundwater).

Taylor began by describing groundwater elevation as the height of water above sea level and displayed a groundwater elevation contour map. Water levels can mean groundwater elevation or depth to water.

Groundwater elevation contours are used to show water levels in an area to determine what flow is like underground. Flows in the Temescal Basin point toward the northwest and turn to the west in Prado.

Taylor noted that groundwater flow direction is generally consistent over time in the basin.

Taylor described groundwater conditions over time in the Temescal Basin and displayed a hydrograph of a representative well. Seasonal and larger-scale patterns can be viewed on the hydrograph. These show responses to changes in climate conditions, weather conditions, wet and dry cycles, and pumping.

Taylor explained that the highest water levels occurred in the 1980s following heavy rains during the late 1970s. In the 1990s, there were some wet periods where water levels did not recover as much as in the 1980s because of increased pumping. Many wells have had their lowest water levels in the last

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10 years because of the drought that occurred between 2013 and 2017. Water levels have been recovering since then, but it is slow process due to limited precipitation.

Taylor next explained groundwater quality in the Temescal Basin. Primary constituents of concern are total dissolved solids and nitrate. Total dissolved solids are a variety of salts that mostly comes from rocks and are elevated in the channel aquifer. Nitrate is also high in some areas and mostly comes from human-caused activities such as historic agriculture and wastewater treatment and disposal. It is important to note that groundwater that is pumped for public consumption in the Temescal Basin is treated and blended before being distributed. The water served to homes and businesses in the Temescal Basin meets federal, state, and county requirements for public health. Other water quality constituents of concern are being tracked and are discussed in the Groundwater Conditions chapter.

Taylor described interconnected surface water, which means that groundwater is shallow enough to be connected to a surface water body. In these areas, high volumes of pumping could lower groundwater elevations. This can become problematic when there are ecosystems that rely on the groundwater, known as groundwater dependent ecosystems. In the Temescal Basin, the primary interconnected surface waters are in the Prado area, which includes wetlands and plants that rely on groundwater.

The Temescal GSA does not want to do anything through groundwater management that will damage the wetlands. Taylor mentioned that subsidence, deformation of the ground surface as a result of groundwater pumping or reduction in groundwater levels, is discussed in the Groundwater Conditions chapter and was not included in the presentation for the sake of brevity since it was not a major issue in the Temescal Basin.

Discussion/Q&A
Hughes opened the floor for questions and comments. Participants were encouraged to answer the following question verbally or using the chat: Do you know of any current or historical problems regarding the use of groundwater in the Temescal Basin? No responses were received.

Water Budget
Reilly presented the purpose of the water budget. The water budget quantifies the inflows and outflows of the Temescal Basin, which vary over time and depend on hydrology and/or management. Inflows in the Temescal Basin include recharge from rainfall, stormwater, and streamflow; reclaimed water from percolation ponds; and subsurface flow from neighboring basins. Outflows occur when water leaves the basin due to pumping, flow to the Santa Ana River, and evapotranspiration.

Reilly explained that the water balance can be viewed as a change in storage, or inflows minus outflows.

The numerical model uses inflows and outflows to calculate the change in storage and elements of the hydrogeologic conceptual model to simulate the groundwater aquifer. This tool can be used to simulate what has happened historically in the Temescal Basin and to simulate future conditions. It will be used to look at the sustainability of the Temescal Basin over the next 50 years and test different scenarios.

Discussion/Q&A
Hughes opened the floor for questions and comments. The following are the questions and comments received in the chat box from participants:
• How do you use the Santa Ana River for groundwater recharge? • Can you discuss or explain sustainability in the Temescal GSP?

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How to Stay Involved
Prior to learning how to stay involved in the process, participants answered a question using a Zoom poll. Hughes explained that all beneficial uses and users would be considered in the Temescal GSP, but the project team wanted to know the interests of stakeholders. Participants responded to the following question: What do you think are the most important uses of groundwater from the Temescal Basin? • Groundwater Dependent Ecosystems
• Industrial Water Supply
• Municipal Water Supply
• Rural Residential Water Supply
• Small Commercial Water Supply
• Small Community Water Supply
The most common answers included groundwater dependent ecosystems, municipal water supply, and rural residential water supply.

Hughes explained how members of the public could be involved throughout GSP preparation, which will continue until January 2022. This was the second public workshop for people to get information about the GSP and give feedback on its development. The third public workshop will be held in summer of 2021 and will focus on sustainability criteria and management actions. The draft GSP presentation in the summer of 2021 will present another opportunity for involvement.

Hughes spoke about other opportunities to learn about GSP development and provide comment. In addition to the workshops, the Technical Advisory Committee meetings are open to the public. The public may listen in on those meetings and speak during the public comment portion. Lastly, the public will have the opportunity to attend and comment at the Adoption Hearing for the final GSP in the fall of 2021.

Draft chapters and other materials such as fact sheets can be found on the project website hosted by the City of Corona Department of Water and Power: CoronaCA.gov/Groundwater. Members of the public can use the form on the website to provide comments. Anyone who wants to be included on the mailing list should email [email protected]. People on the mailing list will receive updates on upcoming public workshops.

6. Wrap Up and Closing
Hughes thanked everyone for participating. The next public workshop will be held during the summer of 2021.

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Appendix A
Presentation Slides

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TEMESCAL GSP PUBLIC WORKSHOP 2
TEMESCAL GSP TALLER COMUNITARIO 2
About the Groundwater Sustainability
Plan (GSP)
The Sustainable Groundwater
Management Act or “SGMA” is a
California law that gives local agencies
new tools for managing groundwater
and planning for the future. The City of
Corona, City of Norco, and Home
Gardens County Water District have
formed the Temescal Groundwater
Sustainability Agency (Temescal GSA)
in order to make a Groundwater
Sustainability Plan for the Temescal
Basin. Since groundwater is such an
important resource for everyone, we
need your help!
Un poco sobre el plan de sostenibilidad
de las aguas subterráneas (GSP)
La Ley de Gestión Sostenible de Aguas
Subterráneas o “SGMA”, por sus siglas en
inglés, es una ley de California que
otorga a las agencias locales nuevas
herramientas para gestionar las aguas
subterráneas y planificar para el futuro.

La Ciudad de Corona, la Ciudad de
Norco y el Distrito Hídrico del Condado
de Home Gardens han formado la
Agencia de Sostenibilidad de
Aguas Subterráneas de la Cuenca
de Temescal (Temescal Groundwater
Sustainability Agency) o Temescal GSA a
fin de crear un Plan de Sostenibilidad
de Aguas Subterráneas para la Cuenca
de Temescal. Dado que las aguas
subterráneas son un recurso muy
importante para todos, ¡necesitamos su
ayuda!

TEMESCAL GROUNDWATER

SUSTAINABLY PLAN
PUBLIC WORKSHOP 2

PLAN DE SOSTENIBILIDAD DE LAS
AGUAS SUBTERRÁNEAS (GSP) DE

TEMESCAL
TALLER COMUNITARIO 2 DE TEMESCAL
MARCH 2, 2021 / 2 DE MARZO DE 2021

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WELCOME

BIENVENIDOS
TEMESCAL GSP PUBLIC WORKSHOP 2
MARCH 2, 2021
Interpretación española

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This public workshop is being recorded and
will be posted on the website:
www.CoronaCA.gov/Groundwater
Este taller público sera grabado y se publicará
en el sitio web:
www.CoronaCA.gov/Groundwater

WORKSHOP PURPOSE
PROPÓSITO DE TALLER COMUNITARIO
» Give Temescal Groundwater Sustainability Plan development updates.

Proporcionar actualizaciones del desarrollo del Plan de sostenibilidad de aguas subterráneas de Temescal.
» Introduce the hydrogeologic conceptual model, groundwater conditions, and water budget.

Introducir el modelo conceptual hidrogeológico, las condiciones del agua subterránea y el presupuesto de agua.

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WORKSHOP PURPOSE
PROPÓSITO DE TALLER COMUNITARIO
» Learn what you think the most important uses of groundwater are and if you know of any current or historical problems regarding the use of groundwater in the Temescal Basin.

Conozca cuáles son los usos más importantes de las aguas subterráneas y si conoce algún problema actual o histórico con respecto al uso de las aguas subterráneas en la Cuenca del Temescal.

HOW TO USE ZOOM
CÓMO UTILIZAR ZOOM

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MARCH 2, 2021
TEMESCAL GSP PUBLIC WORKSHOP 2

INTRODUCTIONS

INTRODUCCIONES

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TEMESCAL GSA

CONSULTANT TEAM

EQUIPO DE CONSULTORES
Jack Hughes
Kearns & West
Chad Taylor
Todd Groundwater
Maureen Reilly
Todd Groundwater

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TIPS FOR A PRODUCTIVE DISCUSSION
CONSEJOS PARA UNA DISCUSIÓN

PRODUCTIVA
» One speaker at a time
Solo una persona habla a la vez
» Keep input concise
Sea conciso al hablar
» Actively listen
Escuche activamente
» Offer solutions
Ofrezca soluciones

YOUR INPUT MATTERS
SU OPINIÓN ES IMPORTANTE
» The planning team will consider your comments as
they prepare the Groundwater Sustainability Plan.

El equipo de planificación considerará sus
comentarios mientras preparan el Plan de
sostenibilidad de aguas subterráneas.
» Your input will be recorded, organized
thematically, and presented in a workshop
summary on the project website.

Sus comentarios serán registrados,
organizados temáticamente y presentados en un
resumen del taller en el sitio web del proyecto.

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REVIEW OF GROUNDWATER

SUSTAINABILITY PLAN DEVELOPMENT

REPASO DEL PLAN DE SOSTENIBILIDAD
DE LAS AGUAS SUBTERRÁNEAS

SUSTAINABLE GROUNDWATER

MANAGEMENT ACT (SGMA)
Landmark legislation in 2014
» Recognizes that groundwater management in California
is best accomplished locally
Legislación histórica en 2014
» Reconoce que la gestión de las aguas subterráneas en
California se logra mejor a nivel local

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GROUNDWATER SUSTAINABILITY PLANS

PLANES DE SOSTENIBILIDAD DE LAS AGUAS
SUBTERRÁNEAS
»Groundwater sustainability plans are detailed road
maps for how groundwater basins will achieve
long term sustainability.
» Los planes de sostenibilidad de las aguas
subterráneas actuan como mapas que detallan la
ruta que hay qe seguir para que cuencas de aguas
subterráneas logren la sostenibilidad a largo plazo.

THE TEMESCAL BASIN

LA CUENCA DEL TEMESCAL
» DWR categorized
Temescal Basin as a
Medium Priority Basin
La Cuenca del Temescal
fue desginada por DWR
como Cuenca de
Prioridad Media
» Contiguous and
connected
Contigua y conectada

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GSA ORGANIZATION / ORGANIZACÍON
Staff and Consultants Staff and Co
Personal y
d Consultants
y Consultores
• Corona DWP Staff
• Todd Groundwater
• Carollo Engineers
• Kearns & West
City of Corona
Technical Advisory Committee chnical Ad
Comité
Advisory C
é Asesor
ry Committ C
or Técnico
• Public agencies/Agencias públicas
• Local businesses/Empresas locales
• Well owners/Propietarios de pozos
• Community interests/Intereses comunitarios
Other agencies and interested parties/Otras agencias y partes interesadas Department of Water and Power Department of W
Departamento
of Water and
o de Aqua y
nd Power
y Energía
City of Norco
Home Gardens Home Gardens
County Water District

WARM UP QUESTION

PREGUNTAS DE CALENTAMIENTO
» How many major aquifers are there in the
Temescal Basin?
¿Cuántos acuíferos significantes hay en la Cuenca
del Temescal?
» Two / Dos
» Three / Tres
» Five / Cinco
» Ten / Diez

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HYDROGEOLOGIC CONCEPTUAL
MODEL

MODELO CONCEPTUAL

HYDROGEOLOGICO

HYDROGEOLOGIC CONCEPTUAL MODEL

MODELO CONCEPTUAL HYDROGEOLOGICO
Includes descriptions of:
» Basin boundaries,
geology, aquifers and
aquitards, aquifer
properties, and
groundwater use
Maps and Graphics
showing:
» Topography, surface water
features, geology, soils,
aquifer locations, basin
thickness, and crosssections
Incluye descripciones de:
» Límites de cuencas,
geología, acuíferos y
acuitardos, propiedades
de acuíferos, y uso de
aguas subterráneas
Mapas y gráficos que
muestran:
» Topografía, características
de aguas superficiales,
geología, tipos de tierra,
ubicaciones de acuíferos,
espesor de cuenca,
secciones transversales

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SURFICIAL

GEOLOGY
GEOLOGÍA

SUPERFICIAL

CHANNEL

AQUIFER
EL ACUÍFERO

DEL CANAL

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CROSS SECTIONS

SECCIONES

TRANSVERSALES

CROSS SECTION A
SECCIÓN TRANSVERSAL - A
Channel Aquifer is the principal aquifer
El Acuífero del Canal es el principal acuífero

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HYDROGEOLOGIC CONCEPTUAL MODEL
MODELO CONCEPTUAL HYDROGEOLÓGICO

DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS

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GROUNDWATER CONDITIONS

CONDICIONES DE AGUAS
SUBTERRÁNEAS

GROUNDWATER CONDITIONS
CONDICIONES DE AGUAS SUBTERRÁNEAS
Presentation of current and historical conditions
» Including groundwater elevations, water quality,
interconnected surface water, and subsidence
Presentación de las condiciones actuales e históricas
» Incluyendo las elevaciones de las aguas subterráneas, la calidad del agua, las aguas superficiales
interconectadas y el hundimiento

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GROUNDWATER

ELEVATION

CONTOURS

CONTORNOS DE
ELEVACIÓN DE
AGUA
SUBTERRÁNEA

HISTORICAL GROUNDWATER ELEVATIONS
ELEVACIONES HISTÓRICAS DE LAS AGUAS
SUBTERRÁNEAS
Corona Well 15

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GROUNDWATER

QUALITY

CALIDAD DEL
AGUA
SUBTERRÁNEAS

INTERCONNECTED

SURFACE WATER

AGUA SUPERFICIAL

INTERCONECTADA

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DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS
» Do you know of any current or historical problems
regarding the use of groundwater in the Temescal
Basin?
¿Conoce algún problema actual o histórico sobre
el uso de aguas subterráneas en la Cuenca del
Temescal?

WATER BUDGET

PRESUPUESTOS DE AGUAS

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WATER BUDGET PURPOSE
PROPÓSITO DEL PRESUPUESTO DEL AGUA
»A water budget quantifies the inflows and outflows
of the Temescal Basin over time
Un presupuesto hídrico cuantifica los flujos de
entrada y salida de la Cuenca del Temescal a lo
largo del tiempo
»Both inflows and outflows vary from year to year,
depending on hydrology or management
Tanto los flujos de entrada como los de
salida varían de un año a otro, dependiendo de la
hidrología o la gestión
WATER BUDGET – INFLOWS
PRESUPUESTO DEL AGUA – FLUJO DE

ENTRADA
Water enters the
groundwater basin
through:
» Recharge from rainfall,
stormwater, and
streamflow
» Reclaimed Water
percolation ponds
» Subsurface flow from
neighboring basins
El agua entra en la
cuenca de aguas
subterráneas a través de:
» Recarga natural por
lluvias, aguas pluviales y
flujo de arroyos
» Estanques de
percolación de agua
recuperada
» Flujo subterráneo de las
cuencas vecinas

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WATER BUDGET – INFLOWS
PRESUPUESTO DEL AGUA – FLUJOS

DE ENTRADA
39 Temescal Wash
Rainfall
Reclaimed Reclaim
Water
Subsurface bsurface
Inflow
WATER BUDGET – OUTFLOWS
PRESUPUESTO DEL AGUA – FLUJO DE SALIDA
Water leaves the
groundwater basin
through:
» Pumping
» Flow to the Santa Ana
River
» Evapotranspiration
El agua deja la cuenca
de agua subterránea a
través de:
» Pozos de Bombeo
» Flujos al río Santa Ana
» Evapotranspiración

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WATER BUDGET – OUTFLOWS
PRESUPUESTO DEL AGUA – FLUJO DE SALIDA
41 Pumping Santa Ana nta Ana
River
Evapotranspiration

CHANGE IN STORAGE
» Inflows – Outflows = Change in Storage
Flujo de Entrada – Flujo de Salida - Cambio en el almacenamiento » Numerical model can simulate future conditions
El modelo numérico puede simular condiciones futuras

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DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS
WHAT DO YOU THINK?
¿QUÉ PIENSAS?
» What do you think are the most important uses of groundwater from the Temescal Basin? (Choose up to three)
¿Cuáles cree usted que son los usos más importantes de las aguas subterráneas de la Cuenca del Temescal? (Elija hasta tres) » Groundwater Dependent Ecosystems/Ecosistemas dependientes del agua subterránea
» Industrial Water Supply/ Suministro de agua industrial » Municipal Water Supply/Suministro de agua municipal
» Rural Residential Water Supply/ Suministro de agua residencial en áreas rurales
» Small Commercial Water Supply/ Suministro de agua para negocios comerciales pequeños
» Small Community Water Supply/Suministro de agua para
comunidades pequeñas

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HOW TO STAY INVOLVED
CÓMO MANTENERSE INVOLUCRADO

PUBLIC WORKSHOPS
TALLERES PÚBLICOS
2021
2020
Data Compilation / Data Compilation /
Management System
Plan Area / Institutional rea / Institu
Setting
Hydrogeologic Hydrogeologic
Conceptual Model / Conceptual Model tual Model /
Groundwater Conditions
Groundwater Model / roundwater Model
Water Budgets
Sustainability Goals and nability Goa
Criteria
Management Actions, Management Actions,
Projects, and Monitoring
Plan Development
Public Workshop 1
Kickoff and Introduction to
SGMA
Public Workshop 2
Hydrogeologic Conceptual
Model, Groundwater
Conditions, and Water
Budget
Public Workshop 3
Sustainability Criteria &
Management Actions
Draft GSP Presentation

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PUBLIC WORKSHOPS
TALLERES PÚBLICOS
2021
2020
Recopilación Recopilación deDatos /
Sistema de
ión de Dato
e Gestión
Área del Plan / Marco del Plan / Mar
Institucional
l Pl /M
Modelo Conceptual Modelo Conceptual
Hidrogeológico / Hidrogeológico /
Condiciones Aguas ondiciones ondiciones Agua
Subterráneas
elo Conceptual lo Conceptual
Modelo deAguas
Subterráneas
s
as/
o Conceptual
Subterrá Subterrá
Presupuestos
ánea
os de
eas/
e Aguas
Criterios riterios yMetas de
Sostenibilidad
Acciones de Manejo, Acciones de Manejo,
Proyectos y Monitoreo
Desarrollo de Plan
Taller Comunitario 1
Inicio y Presentación de
SGMA
Taller Comunitario 2
Modelo Conceptual
Hidrogeológico, Condicio
nes de Aguas
Subterráneas, y
Presupuestos de Aguas
Taller Comunitario 3
Criterios de Sostenibilidad
y Acciones de Gestión
Presentación Inicial de GSP

OTHER MEETINGS

OTRAS REUNIONES
» Technical Advisory Committee Meetings
Juntas del Comité Asesor Técnico
» Adoption Hearing for Final GSP
Audiencia de adopción del GSP final

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WEBSITE

SITIO WEB

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THANK YOU

GRACIAS

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Temescal Basin Public Workshop 3
Workshop Summary

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Contents

1. Background ...............................................................................................................................1

2. Pre-Workshop Outreach .............................................................................................................2

3. When and Where.......................................................................................................................2

4. Attendance and Social Media Views.............................................................................................2

5. Summary...................................................................................................................................2 Welcome and Introductions .....................................................................................................2 Review of Groundwater Sustainability Plan Development...........................................................3 Groundwater Sustainability Plan Development Update...............................................................3 Sustainable Management Criteria.............................................................................................3 Projects and Management Actions ...........................................................................................6 Groundwater Sustainability Plan Implementation ......................................................................7 How to Stay Involved..............................................................................................................8

6. Wrap Up and Closing..................................................................................................................8 Appendix
Presentation Slides

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SGMA requires the formation of a locally controlled Groundwater Sustainability Agency (GSA), which is responsible for developing and implementing a Groundwater Sustainability Plan (GSP). The GSP outlines how to achieve groundwater sustainability within 20 years of its adoption. The City of Corona, City of Norco, and Home Gardens County Water District have formed the Temescal Basin Groundwater Sustainability Agency (Temescal GSA) to create a GSP for the Temescal Basin.

To share information and get input from stakeholders and the public, the Temescal GSA has been holding a series of public workshops, of which this is the third. Public Workshop 1, conducted on September 29, 2020, focused on communicating basic information about SGMA, the Temescal Basin, GSP development, and what sustainability means in a GSP. Participants were asked for input about their groundwater interests and what they thought was important for the future of groundwater in the Temescal Basin.

The second Public Workshop, conducted on March 2, 2021, focused on providing updates on the Temescal GSP development and introducing the hydrogeologic conceptual model, groundwater conditions, and water budget. Participants were asked for their input on what they thought the most important uses of groundwater were and if they knew of any current or historical problems regarding the use of groundwater in the Temescal Basin.

Public Workshop 3, conducted on July 8, 2021, focused on providing further updates on the Temescal GSP development and presenting the sustainability management criteria, projects and management actions, and implementation plan. Participants were asked to provide input on the sustainable management criteria, how the volume for groundwater in the Temescal Basin could be increased, and ideas for making groundwater more sustainable.

This summary documents the outreach methods, time and location, attendance, and major topics presented and discussed at this third public workshop.

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2. Pre-Workshop Outreach
The Temescal GSA used a variety of methods to inform stakeholders and community members about the workshop and encourage participation, as shown in Table 1.

Table 1: Pre-Workshop Outreach Methods
Method Description
Social Media Posts The City of Corona and City of Norco posted information about the workshop on their Facebook pages.

Emails Invitation emails were sent to those on the interested parties list.

Community Leader
Meetings
Two meetings were held on June 29 and July 1. The purpose was to provide information on local water supply to community leaders, learn about needs and perspectives related to the Temescal GSP in vulnerable communities, and get input on what other stakeholders to invite.

3. When and Where
The workshop was held on July 8, 2021 from 4:00 to 6:00 p.m.

4. Attendance and Social Media Views
Approximately 18 people attended the Zoom virtual meeting, including six stakeholder participants.

Spanish interpretation was available for participants to access during the Zoom virtual meeting. Others viewed the workshop on Facebook Live, YouTube, and Corona TV. Post-workshop statistics indicated 18 views on YouTube.

5. Summary
Welcome and Introductions
Jack Hughes, facilitator from Kearns & West, welcomed everyone to the third public workshop for the Temescal GSP. Hughes reviewed the workshop purpose, which was to provide Temescal GSP development updates and present the sustainable management criteria, projects and management actions, and implementation plan. Additionally, the consultant team wanted to hear input from participants on the sustainable management criteria, how the volume for groundwater in the Temescal Basin could be increased, and ideas for making groundwater more sustainable.

Hughes invited the workshop attendees to introduce themselves using the Zoom chat and recognized the Temescal GSA representatives in attendance. Hughes then introduced the additional workshop presenters: Chad Taylor, Principal Hydrogeologist at Todd Groundwater, and Madison Rasmus, Environmental Engineer at Carollo.

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Review of Groundwater Sustainability Plan Development
Taylor first reviewed background information on GSP development (see the Appendix for presentation slides for this and the following sections). SGMA is landmark legislation established in 2014 following a long period of statewide drought. SGMA has altered how water is managed in California by providing local agencies with authority and guidance for how to assess sustainability and critical tools to help achieve or maintain sustainability in areas where groundwater is an important water source. Taylor explained that GSPs are detailed road maps for how groundwater basins will achieve or maintain longterm sustainability.

Taylor described the Temescal Basin area, which covers most of the City of Corona, about half of the City of Norco, and the western part of the Home Gardens County Water District. One GSA, the Temescal GSA, was formed for the Temescal Basin because the area is hydrologically connected and has historically been managed as one unit. The California Department of Water Resources has designated the Temescal Basin as a medium priority basin, which required the Temescal GSA to prepare the Temescal GSP.

Taylor next described the organization of the Temescal GSA. The City of Corona, the City of Norco, and Home Gardens County Water District formed the Temescal GSA in 2017 through a memorandum of understanding. The City of Corona is leading the GSP effort with support from Corona Department of Water and Power staff and additional consultants. The Technical Advisory Committee (TAC) has provided input during GSP preparation and includes members that represent public agencies, local businesses, well owners, and community interests. The GSP process is founded on public engagement and stakeholder outreach, which is the purpose of the public workshops.

Groundwater Sustainability Plan Development Update
Taylor provided a status update on the Temescal GSP. The individual chapters that have been prepared are the Introduction, Plan Area, Hydrogeologic Conceptual Model, Groundwater Conditions, Monitoring Network, Projects and Management Actions, and Implementation Plan chapters. Most of these chapters are available online for public review; some chapters are currently being reviewed by the TAC and will be uploaded to the GSA website shortly for public review. The consultant team is finalizing the Water Budget and Sustainability Management Criteria chapters. A draft of the Temescal GSP will be compiled and prepared for public release later in summer 2021.

Discussion/Q&A
Hughes opened the floor for questions and comments. There were no questions or comments from participants after this presentation.

Sustainable Management Criteria
Taylor presented the draft sustainable management criteria for the Temescal Basin. He first defined sustainable management as the management and use of groundwater without causing undesirable results. Taylor explained that the first part of defining sustainability locally is to establish a sustainability goal. The sustainability goal helps to provide a framework for how the sustainability indicators are assessed. The Temescal GSA and TAC worked together to develop the following goal:

To sustain groundwater resources for the current and future beneficial uses of the Temescal Basin in a manner that is adaptive and responsive to the following objectives:

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• Provide a long-term, reliable, and efficient groundwater supply for municipal, industrial, and other uses;
• Provide reliable storage for water supply resilience during droughts and shortages; • Protect groundwater quality;
• Support beneficial uses of interconnected surface waters; and • Support integrated and cooperative water resource management.

Taylor provided an overview of the six indicators for evaluating groundwater sustainability in a basin:
chronic lowering of groundwater levels, reduction of groundwater storage, degradation of water quality, depletion of interconnected surface water affecting beneficial uses, land subsidence affecting land uses, and seawater intrusion, which is not applicable in the Temescal Basin.

Thresholds need to be developed for the five applicable sustainable management criteria for the Temescal Basin. First, undesirable results, or conditions that should be avoided, are defined for each indicator. Once undesirable results are defined, they are used to develop minimum thresholds for assessing each of the sustainability indicators. Next, measurable objectives are set. Beneficial uses in the Temescal Basin also need to be evaluated and considered for each of the sustainability indicators.

These include the following:
• Municipal Water Supply
• Industrial Water Supply
• Small Community Water Supply
• Small Commercial Water Supply
• Groundwater Dependent Ecosystems
• Recreational Surface Water Supply
Taylor next explained how the sustainable management criteria were established for each indicator, starting with chronic lowering of groundwater levels. Since there is no record of wells being dry in the Temescal Basin during the range of historic groundwater levels, the assumption was made that historic low groundwater levels could be repeated in the future. The consultant team established a set of representative key wells in the Temescal Basin. These key wells have a long history for monitoring groundwater levels and will continue to be used for monitoring in the future. Taylor explained that the minimum threshold for defining undesirable results relative to chronic lowering of groundwater levels is defined at each key well by the historic minimum static groundwater elevation (or maximum historical depth to groundwater).

Taylor then presented the sustainable management criteria for reduction of groundwater storage, noting that storage is related to groundwater levels. He explained that GSP regulations allow the use of groundwater level minimum thresholds and measurable objectives as a proxy, and that the historic minimum-based groundwater level threshold is well-suited for use as a proxy for groundwater storage.

The minimum threshold for groundwater storage is fulfilled by the minimum threshold for groundwater levels (using the historical minimum).

Taylor presented the sustainable management criteria for degradation of water quality. He explained that the Temescal GSA is not responsible for local groundwater quality problems or degradation caused by others. Groundwater quality is under regulatory oversight by state agencies. However, the Temescal GSA is responsible for undesirable results associated with increased concentrations of water quality

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contaminants of concern due to groundwater management, such as through recharge and changes in pumping patterns related to groundwater management. The primary contaminants of concern in the Temescal Basin (historically and currently) are total dissolved solids (TDS) and nitrate. The minimum threshold is defined as a statistically significant increase in the percentage of wells with averages exceeding the maximum contaminant level for TDS and/or nitrate, relative to current conditions.

Statistically significant is defined as more than a 10 percent increase in the number of wells in a 5-year period.

Taylor next presented the sustainable management criteria for depletions of interconnected surface water affecting beneficial uses. He explained that groundwater close to the ground surface can interact with vegetation or stream flows. Vegetation that relies on groundwater as its primary source of water is called riparian vegetation. Ecosystems that rely on groundwater are referred to as groundwater dependent. Impacts associated with reductions of stream flow, which affect groundwater dependent ecosystems, and potential impacts to riparian vegetation are assessed. Taylor displayed a map showing the maximum depth to water of wells in the Temescal Basin. Groundwater levels in all the wells in the main portion of the Temescal Basin have never been less than 40 feet deep. Water levels in wells in and near the Prado Basin area have never been deeper than 15 feet. Because riparian vegetation roots typically reach 20 to 30 feet at most, it is unlikely that the main part of the basin supports any riparian vegetation; however, the Prado Basin area likely supports riparian vegetation with its shallow groundwater levels. Depths in all wells around the Prado Basin and trends for groundwater levels, groundwater pumping, river flow, and rainfall were analyzed to determine if the Prado wetlands were supported by groundwater. The conclusion is that the Prado wetlands are more dependent on surface inflows than groundwater inflow. Changes in surface inflows have much more influence than changes in groundwater pumping or levels to the north or south. More monitoring is needed in the southern Prado Basin between the Prado wetlands and pumping centers in the Temescal Basin. Taylor explained that the minimum threshold for depletion of interconnected surface water is the historical maximum depth to water in shallow monitoring wells in the southern Prado area, correlated with Temescal Basin pumping or groundwater levels.

Finally, Taylor presented the sustainable management criteria for land subsidence affecting land uses, explaining that when water is removed from an aquifer, fine-grain materials can compact and the ground surface can decline. Ground surface elevation changes that may be related to subsidence statewide has been estimated by satellite measurements in data provided by the California Department of Water Resources dating from 2015 to 2019. This includes ground surface elevation changes in the Temescal Basin. This method has a margin of error of approximately 0.1 feet. The satellite data estimates show ground surface change in the Temescal Basin ranging between a rise of 0.08 feet to a fall of 0.08 feet. This is very small and within the margin of error. Taylor presented the minimum threshold for subsidence, defined as a rate of decline equal to or greater than 0.2 feet in any 5-year period. This has been considered in terms of a cumulative decline equal to or greater than 1.0 foot of decline since 2015, which represents current conditions and aligns with the SGMA start date.

Discussion/Q&A
Hughes opened the floor for questions and comments. There were no questions or comments from participants after this presentation.

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Projects and Management Actions
Rasmus presented the draft projects and management actions for the Temescal GSP. She explained the three groupings of actions: baseline, planned, and potential future. Baseline refers to existing or established commitments to projects or actions. Planned actions are developed and evaluated projects or actions. Potential future actions describe projects or actions to be implemented later to achieve sustainability goals.

Rasmus began by describing the baseline projects. The first is groundwater treatment at the Temescal Desalter to reduce nitrates, total suspended solids (TSS), TDS, and other contaminants of concern for the drinking water supply. The second project is water reclamation facility (WRF) percolation ponds that discharge from City of Corona-owned WRFs to percolation ponds that recharge the Temescal Basin.

The third project includes water-level quality assurance and quality control activities that maintain the reliability of ongoing groundwater elevation data. The final project Rasmus presented was the Western Riverside County Regional Authority (WRCRWA) plant that will soon supply recycled water for local irrigation use.

Rasmus next reviewed the baseline management actions. These include Water Shortage Contingency Plans, which are plans that detail the stages of water shortage and conservation response based on an agency’s available supply and deficit, and Water Conservation Programs, which include response actions to reduce water use in the stages of a water shortage. Additional management actions include the Western Municipal Water District Integrated Regional Water Management Plan, which is a coordinated, long-range regional water quantity and quality management strategy, and the Temescal GSA’s involvement in the Santa Ana Watershed Project, which is a coordinated management group formed to protect the Santa Ana River Basin and associated water resources.

Rasmus then reviewed the three projects included in planned actions. First, the Potable Reuse Feasibility Study will look at the possible use of future reclaimed water supply. Second, the mountain runoff capture investigation would explore options for operational changes allowing for additional benefit of groundwater recharge by using storm event runoff that is collected in Riverside County Flood Control and Water Conservation District basins. This would be at the edges of the basin adjacent to the Santa Ana mountains. Lastly, the interconnected surface water monitoring wells project would include three shallow monitoring wells drilled into the Prado Management Area to allow for groundwater elevation monitoring.

Rasmus provided more information on the interconnected surface water monitoring wells project since its implementation date is within the first year of Temescal GSP adoption. Wells will be sited in the southern area of the Prado Management Area. There is no active groundwater monitoring in this location so drilling wells will allow the Temescal GSA to better understand the relationship between the basin and interconnected water in the Prado Wetlands. The project will consist of three groundwater wells about 40-60 feet deep that will allow for continuous groundwater elevation data collection in the area. The data will be incorporated in the 5-year GSP update and these monitoring wells will inform future management actions in the Santa Ana River Watershed.

Lastly, Rasmus presented potential future actions. Data collected from the Prado Management Area monitoring wells will be used as part of monitoring for undesirable results to interconnected surface water in Prado. If this monitoring identifies potential undesirable results to interconnected surface water

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in the Prado Management Area, then coordination will be needed with upstream Santa Ana River partners as a management action. If groundwater levels in the Prado Management Area are falling, this approach will allow for coordinated solutions.

There are two additional future management actions. One is for future groundwater treatment, which would entail implementing advanced treatment for previously detected per- and polyfluoroalkyl substances (PFAS), TDS, nitrate, and trichloropropane (TCP). Other future management actions are for urban stormwater treatment, capture, and recharge, which is an exploration of urban stormwater harvesting to offset water supply and/or provide for groundwater recharge.

Discussion/Q&A
Hughes opened the floor for questions and comments. Participants were encouraged to answer the following question verbally or using the chat:
• Are there other potential groundwater related projects we should consider? • Do you have ideas for how the volume of groundwater in the Temescal Basin could be increased? • Do you have ideas for making groundwater more sustainable in the Temescal Basin? The following are the questions and comments received in the chat box from participants:
• Could you confirm that Western Municipal Water District (WMWD) has an Integrated Regional Water Management Plan (IRWMP)?
• Since the 2008 WMWD IRWMP is a bit dated, I would recommend also citing the 2018 Santa Ana Watershed Project Authority (SAWPA) One Water One Watershed (OWOW) Plan. • If the GSA is not responsible for impacts to groundwater dependent ecosystems resulting from reductions in surface water flow beyond its control, how does the Temescal GSA intend to determine if reductions in Western Riverside County Regional Wastewater Authority (WRCWRA) flows are impacting groundwater dependent ecosystems in the Prado Basin? • I would recommend that the groundwater basin planning reflect the storage project called Santa Ana River Conservation and Conjunctive Use Program (SARCCUP) of which WMWD is a member.

Groundwater Sustainability Plan Implementation
Taylor presented for discussion four categories of GSP implementation: monitoring of groundwater conditions and use, annual reports, carrying out of projects and management actions, and periodic evaluations/GSP updates. First, monitoring of groundwater conditions and use will occur often throughout the basin. This includes groundwater levels, water quality, stream flow, subsidence, and water use. Second, the data collected through this monitoring will be compiled into annual reports.

Annual reports include groundwater level data, storage change, water use, and sustainability progress.

Third, carrying out projects and management actions will be an important part of GSP implementation and will be updated and modified over time. Last, periodic evaluations will occur at least every 5 years and GSP updates can occur based on new information becoming available, new projects being added, or the need to modify sustainable management criteria. All modifications should be made to ensure that the GSP continues to provide a reliable roadmap for sustainability for the groundwater basin.

Discussion/Q&A
Hughes opened the floor for questions and comments. There were no questions or comments from participants after this presentation.

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How to Stay Involved
Hughes explained how members of the public could be involved throughout the remainder of the Temescal GSP preparation. Once all chapters are completed later in summer 2021, the draft Temescal GSP will be released for a 90-day period where the public can review and comment on the draft plan.

The public will also have the opportunity to attend and make comments at the Adoption Hearing for the final GSP in winter 2021 before the final GSP is sent to the California Department of Water Resources by January 2022.

Draft chapters and other materials such as fact sheets can be found on the project website hosted by the City of Corona Department of Water and Power: CoronaCA.gov/Groundwater. Members of the public can use the form on the website to provide comments. Information on attending the Temescal GSP Adoption Hearing will also be posted on the website. Anyone who wants to be included on the mailing list to receive communication about the Temescal GSP should email [email protected].

6. Wrap Up and Closing
Hughes thanked everyone for participating.

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Appendix
Presentation Slides

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TEMESCAL GSP PUBLIC WORKSHOP 3
TEMESCAL GSP TALLER COMUNITARIO 3
About the Groundwater Sustainability
Plan (GSP)
The Sustainable Groundwater
Management Act or “SGMA” is a
California law that gives local agencies
new tools for managing groundwater
and planning for the future. The City of
Corona, City of Norco, and Home
Gardens County Water District have
formed the Temescal Groundwater
Sustainability Agency (Temescal GSA)
in order to make a Groundwater
Sustainability Plan for the Temescal
Basin. Since groundwater is such an
important resource for everyone, we
need your help!
Un poco sobre el plan de sostenibilidad
de las aguas subterráneas (GSP)
La Ley de Gestión Sostenible de Aguas
Subterráneas o “SGMA”, por sus siglas en
inglés, es una ley de California que
otorga a las agencias locales nuevas
herramientas para gestionar las aguas
subterráneas y planificar para el futuro.

La Ciudad de Corona, la Ciudad de
Norco y el Distrito Hídrico del Condado
de Home Gardens han formado la
Agencia de Sostenibilidad de
Aguas Subterráneas de la Cuenca
de Temescal (Temescal Groundwater
Sustainability Agency) o Temescal GSA a
fin de crear un Plan de Sostenibilidad
de Aguas Subterráneas para la Cuenca
de Temescal. Dado que las aguas
subterráneas son un recurso muy
importante para todos, ¡necesitamos su
ayuda!

TEMESCAL GROUNDWATER

SUSTAINABLY PLAN (GSP)
PUBLIC WORKSHOP 3

PLAN DE SOSTENIBILIDAD DE LAS
AGUAS SUBTERRÁNEAS (GSP) DE

TEMESCAL
TALLER COMUNITARIO 3 DE TEMESCAL
JULY 8, 2021 / 8 DE JULIO DE 2021

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WELCOME

BIENVENIDOS
TEMESCAL GSP PUBLIC WORKSHOP 3
July 8, 2021
Interpretación española

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This public workshop is being recorded and
will be posted on the website:
www.CoronaCA.gov/Groundwater
Este taller público sera grabado y
sera publicado en el sitio web:
www.CoronaCA.gov/Groundwater

WORKSHOP PURPOSE
PROPÓSITO DE TALLER COMUNITARIO
» Give Temescal Groundwater Sustainability Plan development updates.

Proporcionar actualizaciones del desarrollo del Plan de Sostenibilidad de Aguas Subterráneas de Temescal.
» Present the sustainability criteria, projects and management actions, and implementation plan.

Presentar los criterios de sostenibilidad, proyectos y acciones de gestión, y plan de implementación.

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WORKSHOP PURPOSE
PROPÓSITO DE TALLER COMUNITARIO
» Hear input on sustainability criteria, and how the volume for groundwater in the basin could be increased and ideas for making groundwater more sustainable.

Escuche comentarios sobre criterios de sostenibilidad y cómo se podría aumentar el volumen de agua subterránea en la cuenca e ideas para hacer que el agua subterránea sea más sostenible

HOW TO USE ZOOM
CÓMO UTILIZAR ZOOM

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July 8, 2021
TEMESCAL GSP PUBLIC WORKSHOP 3 INTRODUCTIONS

INTRODUCCIONES

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TEMESCAL GSA CONSULTANT TEAM

EQUIPO DE CONSULTORES
Jack Hughes
Kearns & West
Chad Taylor
Todd Groundwater
Madison Rasmus
Carollo Engineers

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TIPS FOR A PRODUCTIVE DISCUSSION
CONSEJOS PARA UNA DISCUSIÓN

PRODUCTIVA
»One speaker at a time
Solo una persona habla a la vez
»Keep input concise
Sea conciso al hablar
»Actively listen
Escuche activamente
»Offer solutions
Ofrezca soluciones

YOUR INPUT MATTERS
SU OPINIÓN ES IMPORTANTE
» The planning team will consider your comments as
they prepare the Groundwater Sustainability Plan.

El equipo de planificación considerará sus
comentarios mientras preparan el Plan de
Sostenibilidad de aguas subterráneas.
» Your input will be recorded, organized
thematically, and presented in a workshop
summary on the project website.

Sus comentarios serán registrados,
organizados temáticamente y presentados en el
resumen del taller en el sitio web del proyecto.

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REVIEW OF GROUNDWATER

SUSTAINABILITY PLAN DEVELOPMENT

REPASO DEL PLAN DE SOSTENIBILIDAD
DE LAS AGUAS SUBTERRÁNEAS

SUSTAINABLE GROUNDWATER

MANAGEMENT ACT (SGMA)
GESTIÓN SOSTENIBLE DE AGUAS
SUBTERRÁNEAS (SGMA)
Landmark legislation in 2014
» Recognizes that groundwater management in California
is best accomplished locally
Legislación histórica en 2014
» Reconoce que la gestión de las aguas subterráneas en
California se logra mejor a nivel local

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GROUNDWATER SUSTAINABILITY PLANS

PLANES DE SOSTENIBILIDAD DE LAS AGUAS
SUBTERRÁNEAS
»Groundwater sustainability plans are detailed road
maps for how groundwater basins will achieve
long term sustainability.
» Los planes de sostenibilidad de las aguas
subterráneas actuan como mapas que detallan la
ruta que hay que seguir para que cuencas de
aguas subterráneas logren la sostenibilidad a largo
plazo.

THE TEMESCAL BASIN

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GSA ORGANIZATION / ORGANIZACÍON
Staff and Consultants
Personal y Consultores
• Corona DWP Staff
• Todd Groundwater
• Carollo Engineers
• Kearns & West
City of Corona
Technical Advisory Committee
Comité Asesor Técnico
• Public agencies/Agencias públicas
• Local businesses/Empresas locales
• Well owners/Propietarios de pozos
• Community interests/Intereses comunitarios
Other agencies and interested parties/Otras agencias y personas interesadas Department of Water and Power
Departamento de Aqua y Energía
City of Norco
Home Gardens
County Water District GSP DEVELOPMENT UPDATE
ACTUALIZACIÓN DE DESARROLLO

DEL SGP

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GSP STATUS

ESTADO DEL GSP
Individual chapters have been
completed:
» Introduction
» Plan Area
» Hydrogeologic Conceptual Model
» Groundwater Conditions
» Monitoring Network
» Projects and Management Actions
» Implementation Plan
Working on finishing drafts of:
» Water Budget
» Sustainability Criteria
Then will be compiling complete
GSP for distribution
Se han completado capítulos
individuales:
» Introducción
» Área del plan
» Modelo conceptual
hidrogeológico
» Condiciones de las aguas
subterráneas
» Red de supervisión
» Proyectos y acciones de gestión
» Plan de ejecución
Estamos trabajando en la
finalización de borradores de:
» Presupuesto del agua
» Criterios de sostenibilidad
A continuación, se compilará el
GSP completo para su distribución

DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS

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SUSTAINABLE MANAGEMENT

CRITERIA
CRITERIOS DE GESTIÓN

SOSTENIBLE
WHAT IS SUSTAINABLE MANAGEMENT?
¿QUÉ ES LA GESTIÓN SOSTENIBLE?
Chronic lowering of groundwater levels
Reducción crónica de los niveles de aguas subterráneas
Reduction of groundwater storage
Reducción del almacenamiento de aguas subterráneas
Degradation of water quality
Degradación de la calidad del agua
Depletions of interconnected surface water
Agotamiento de aguas superficiales interconectadas
Land subsidence affecting land uses
Hundimiento de tierras que afectan los usos de las tierras Seawater intrusion (not applicable here)
Inactividad de aguas marinas (no aplicable aquí)
The management and use of groundwater without causing undesirable results El gestión y utilización de las aguas subterráneas sin causar resultados indeseables

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SUSTAINABILITY GOAL

OBJETIVO DE SOSTENIBILIDAD
To sustain groundwater resources for the current and future beneficial uses of the Temescal Basin in a manner that is adaptive and responsive to the following objectives:
» Provide a long-term, reliable and efficient groundwater supply for municipal, industrial, and other uses
» Provide reliable storage for water supply resilience during droughts and shortages » Protect groundwater quality
» Support beneficial uses of interconnected surface waters, and » Support integrated and cooperative water resource management.

Sostener los recursos de aguas subterráneas para los usos beneficiosos actuales y futuros de la Cuenca Temescal de manera que sean adaptables y respondan a los siguientes objetivos:
» Proporcionar un suministro de agua subterránea fiable y eficiente a largo plazo para usos municipales, industriales y de otro tipo » Proporcionar almacenamiento fiable para la resistencia del suministro de agua durante sequías y escaseces
» Proteger la calidad del agua subterránea
» Apoyar los usos beneficiosos de las aguas superficiales interconectadas y » Apoyar los recursos hídricos integrados y cooperativos HOW DO WE MEASURE SUSTAINABILITY?
¿CÓMO MEDIMOS LA SOSTENIBILIDAD?
Sustainability Criteria
Criterios de sostenibilidad:
» Undesirable results / Resultados no deseados
• What are undesirable results that we want to avoid?
• ¿Cuáles son los resultados no deseados que queremos evitar? » Minimum thresholds (MT) / Umbrales mínimos (MT)
• How low is too low for water levels?
• ¿Qué tan bajo es demasiado bajo para los niveles de agua? » Measurable objectives (MO) / Objetivos mensurables
(MO)
• What is the desired range of water levels?
• ¿Cuál es el rango deseado de niveles de agua?

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BENEFICIAL USES

USOS BENEFICIOSOS
» Municipal water supply
» Industrial water supply
» Small community water
systems
» Small commercial water
supply
» Groundwater dependent
ecosystems
» Recreational surface water
use
» Suministro de agua
municipal
» Agua para procesos
industriales
» Sistemas de agua
comunitarios pequeños
» Agua para uso comercial
pequeños
» Ecosistemas dependientes
del agua subterránea
» Uso de aguas superficiales
para fines recreativos

GROUNDWATER LEVELS
NIVELES DE AGUA SUBTERRÁNEA
» Define MT as historical low
level in Key Wells
Definir MT como nivel bajo
histórico en Key Wells
» Key Wells are a set of
representative monitoring
wells that will continue to
be monitored
Los pozos clave son un
conjunto representativo de
pozos de monitoreo que
continuarán siendo
monitoreados
Groundwater Level
Nivel de Aguas
Subterráneas
Groundwater Level
Nivel de Aguas
Subterráneas
Operable Range of
Water Levels
Rango Operable de
Niveles de Agua
Well
Screens
Pantallas
de Pozos

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REDUCTION OF GROUNDWATER STORAGE
REDUCCIÓN DEL ALMACENAMIENTO DE
AGUAS SUBTERRÁNEAS
» Groundwater storage is connected to water levels
El almacenamiento de aguas subterráneas está conectado a los niveles de agua
» GSP regulations allow use of groundwater level Minimum Thresholds and Measurable Objectives as a proxy
Las regulaciones del GSP permiten el uso de umbrales mínimos de nivel de aguas subterráneas y objetivos mensurables como proxy » Historical minimum-based water level threshold is well suited to use as a proxy
El umbral histórico de nivel de agua basado en el mínimo es adecuado para su uso como proxy
» Minimum Threshold for storage is fulfilled by the minimum threshold for groundwater levels
El umbral mínimo para el almacenamiento se cumple con el umbral mínimo para los niveles de aguas subterráneas

WATER QUALITY / CALIDAD DEL AGUA
» GSA is not responsible for local problems or degradation caused by others.

GSA no es responsable por los problemas locales o la
degradación causada por otros.
» Groundwater quality is under regulatory oversight by State Agencies.

La calidad de las aguas subterráneas está bajo la
supervisión reglamentaria de las agencias estatales.
» The GSA is responsible for increased concentrations in water quality due to management (recharge, pumping,
etc.).

La GSA es responsable por el aumento de las
concentraciones en la calidad del agua debido a la gestión (recarga, bombeo, etc.).

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WATER QUALITY THRESHOLD

UMBRAL DE CALIDAD DEL AGUA
» Minimum Threshold defined as a statistically significant increase in the percentage of wells with averages exceeding the maximum contaminant level (MCL) for total dissolved solids (TDS) and nitrate, relative to current conditions.

Umbral mínimo definido c omo un aumento
estadísticamente significativo en el porcentaje de pocillos con promedios que exceden el nivel máximo de
contaminante (MCL) para sólidos disueltos totales (TDS) y nitrato, en relación con las condiciones actuales.
» Statistically significant is defined as more than 10 percent increase in number of wells in 5-year period.

Estadísticamente significativo se define como un aumento de más del 10 por ciento en el número de pozos en un
período de 5 años.

INTERCONNECTED SURFACE WATER

AGUAS SUPERFICIALES INTERCONECTADAS
Stream Flow Depletion:

Stream Bed Elevation
Agotamiento del Flujo de la Corriente:

Elevación del Lecho del Arroyo
Riparian Vegetation:

About 20 to 30 feet
Riparian Vegetation:

Cerca de 20 a 30 pies
Coast Live Oak
Red Willow
California Sycamore
Common
Elderberry
Mule Fat
Scalebroom

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DEPTH TO GROUNDWATER
PROFUNDIDAD A LAS AGUAS SUBTERRÁNEAS
Butterfield Well
Maximum Depth to
Water <15 feet
Profundidad Máxima
al Agua <15 pies
Minimum Depth to
Water >40 feet
Profundidad
Mínima al Agua
>40 pies
0 50
100
150
200 Jan-00 Dec-01 Jan-04 Dec-05 Jan-08 Jan-10 Jan-12 Jan-14 Jan-16 Jan-18 Jan-20 Depth below Ground Surface (feet) Temescal Basin Depth to Groundwater
Well 7A Well 22 Well 17A Well 8A Butterfield

PRADO BASIN MAXIMUM DEPTH TO WATER

GROUND SURFACE
Butterfield Well

DEPTH TO GROUNDWATER
PROFUNDIDAD A LAS AGUAS SUBTERRÁNEAS

Page 2203 of 3451 ends

INTERCONNECTED SURFACE WATER

CONCLUSIONS

CONCLUSIONES SOBRE LAS AGUAS

SUPERFICIALES INTERCONECTADAS
» Prado wetlands are more dependent on surface inflows than groundwater inflow
Los humedales del Prado dependen más de los flujos de entrada superficiales que los flujos de entrada de aguas subterráneas » Changes in surface inflows have much more influence than changes in groundwater pumping or levels to the north or south Los cambios en los flujos de entrada superficiales tienen mucha más influencia que los cambios en el bombeo de aguas subterráneas o los niveles hacia el norte o el sur
» More monitoring is needed in the southern Prado between the wetlands and pumping centers in Temescal Basin
Se necesita más vigilancia en el sur del Prado entre los humedales y los centros de bombeo en la cuenca Temescal

INTERCONNECTED SURFACE WATER

THRESHOLD

UMBRAL DE AGUAS SUPERFICIALES

INTERCONECTADAS
» Minimum Threshold for depletion of interconnected
surface water is historical maximum depth to water in
shallow monitoring wells in the southern Prado area,
correlated with Temescal Basin pumping or water
levels
El umbral mínimo para el agotamiento del agua
superficial interconectada es el nivel mínimo histórico del agua (profundidad máxima al agua) en pozos de monitoreo poco profundos en el área sur del Prado, correlacionado con el bombeo de la Cuenca Temescal
o los niveles del agua

Page 2204 of 3451 ends

SUBSIDENCE

HUNDIMIENTO DE LA TIERRA

Margin of error
in satellite
measurements
is 0.1 ft

SUBSIDENCE THRESHOLD

UMBRAL DE HUNDIMIENTO DE LA TIERRA
» Defined as rate of decline equal to or greater than

0.2 feet in any five-year period
Definido como una tasa de disminución igual o
superior a 0.2 pies en cualquier período de cinco
años
» This has been considered in terms of a cumulative
decline equal to or greater than one foot of
decline since 2015
Esto se ha considerado en términos de una
disminución acumulada igual o mayor a un pie de
disminución, desde el 2015

Page 2205 of 3451 ends

DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS

PROJECTS AND MANAGEMENT

ACTIONS

PROYECTOS Y ACCIONES DE
GESTIÓN

Page 2206 of 3451 ends

PROJECT MANAGEMENT/ACTION

GROUPINGS
»Group 1: Baseline Actions
»Grupo 1: Acciones de línea de base
»Group 2: Planned Actions
»Grupo 2: Acciones planeadas
»Group 3: Potential Future Actions
»Grupo 3: Posibles acciones futuras
GROUP 1 PROJECTS
PROYECTOS DEL GRUPO 1
» Groundwater Treatment: Treatment at the Temescal
desalter to reduce nitrates, TDS, TSS and other
contaminants for the City’s drinking water supply
» Tratamiento de aguas subterráneas: tratamiento en la
desaladora de Temescal para reducir los nitratos, TDS, TSS y otros contaminantes para el suministro de agua potable de la ciudad.
» Water Reclamation Facility Percolation Ponds: Discharge from percolation ponds that recharge the Basin
» Estanques de percolación de instalaciones de recuperación de agua: descarga de estanques de percolación que
recargan la cuenca

Page 2207 of 3451 ends

GROUP 1 PROJECTS
PROYECTOS DEL GRUPO 1
» Water Level QA/QC: Maintaining the reliability of
groundwater elevation data
» Control de calidad / control de calidad del nivel del agua:
mantenimiento de la confiabilidad de los datos de
elevación del agua subterránea
» WRCRWA Recycled Water: This plant will soon produce
recycled water for local irrigation use
» Agua reciclada de WRCRWA: esta planta pronto producirá agua reciclada para uso de riego local.

GROUP 1 MANAGEMENT ACTIONS
ACCIONES DE GESTIÓN DEL GRUPO 1
» Water Shortage Contingency Plans: Stages of water
shortage and conservation response based on available
water supply
» Planes de contingencia de escasez de agua: Etapas de
escasez de agua y respuesta de conservación en función
del suministro de agua disponible
» Water Conservation Programs: Response actions to reduce water use in accordance with water shortage
» Programas de conservación de agua: acciones de respuesta para reducir el uso de agua de acuerdo con la escasez de agua

Page 2208 of 3451 ends

GROUP 1 MANAGEMENT ACTIONS
ACCIONES DE GESTIÓN DEL GRUPO 1
» WMWD IRWMP: Coordinated, long-range regional water
quality and management strategy
» WMWD IRWMP: Estrategia regional coordinada de gestión y calidad del agua a largo plazo
» Santa Ana Watershed Involvement: Coordinated
management group to protect the Santa Ana River basin
and associated water resources
» Participación de la cuenca de Santa Ana: grupo de gestión coordinado para proteger la cuenca del río Santa Ana y los recursos hídricos asociados
GROUP 2 PROJECTS
PROYECTOS DEL GRUPO 2
» Potable Reuse Feasibility Study: Study to look at use potential for near to future reclaimed water supply
» Estudio de viabilidad de reutilización de agua potable: estudio para analizar el potencial de uso del suministro de agua recuperada en el futuro cercano
» Mountain Runoff Capture Investigation: Runoff during storm events is collected into existing RCFCWCD basins to mitigate flooding. This study would explore options for operational changes to allow for additional benefit of groundwater recharge.
» Investigación de captura de escorrentía de montaña: La escorrentía durante tormentas se recolecta en las cuencas RCFCWCD existentes para mitigar las inundaciones. Este estudio exploraría opciones para cambios operativos que permitan un beneficio adicional de la recarga de agua subterránea.

Page 2209 of 3451 ends

GROUP 2 –

MONITORING
WELLS

PROJECT
GRUPO 2 -

PROYECTO DE

POZOS DE

MONITOREO
GROUP 2 – MONITORING WELLS PROJECT
GRUPO 2 - PROYECTO DE POZOS DE MONITOREO
» 3 wells, 40-60 feet deep
» 3 pozos, de 40 a 60 pies de
profundidad
» Continuous groundwater
elevation data collection to be
used in 5-year GSP update
» Recopilación continua de
datos de elevación del agua
subterránea que se utilizará
en la actualización del GSP en
5 años
» Data will inform future
management actions
» Los datos informarán las
acciones de gestión futuras

Page 2210 of 3451 ends

GROUP 3 MANAGEMENT ACTIONS
ACCIONES DE GESTIÓN DEL GRUPO 3
» Santa Ana River Wastewater Discharge Coordination for Shallow Groundwater Conditions: Contingent on Prado
monitoring well installation. If groundwater levels in Prado are falling, this approach will entail coordination with upstream partners for solutions
» Coordinación de descarga de aguas residuales del río
Santa Ana para condiciones de aguas subterráneas poco
profundas: depende de la instalación del pozo de
monitoreo de Prado. Si los niveles de agua subterránea en Prado están cayendo, este enfoque implicará la
coordinación con los socios del alrededor para encontrar soluciones
GROUP 3 PROJECTS
PROYECTOS DEL GRUPO 3
» Future Groundwater Treatment: Implementation of
advanced treatment to treat for PFAS as well as TDS,
nitrate, and TCP
» Tratamiento de aguas subterraneas en el futuro:

Implementacion de tratamiento avanzado para tratar agua de PFAS al mismo tiempo que TDS, nitrato, y TCP
» Urban Stormwater Treatment, Capture, and Recharge:

Exploration of urban stormwater harvesting to offset water supply and/or provide for groundwater recharge
» Tratamiento, captura y recarga de aguas pluviales urbanas:
exploración de la captación de aguas pluviales urbanas
para compensar el suministro de agua y / o proporcionar recarga de aguas subterráneas Page 2211 of 3451

DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS
» Are there other potential groundwater related projects we should consider?
¿Hay otros proyectos potenciales relacionados con las aguas subterráneas que deberíamos considerar?
» Do you have ideas for how the volume of groundwater in the Basin could be increased?
¿Tiene ideas sobre cómo se podría aumentar el volumen de aguas subterráneas en la cuenca?
» Do you have ideas for making groundwater more sustainable in the Basin?
¿Tiene ideas para hacer que las aguas subterráneas sean más sostenibles en la cuenca?

GSP IMPLEMENTATION
IMPLEMENTACIÓN DEL GSP

Page 2212 of 3451 ends

WHAT IS GSP IMPLEMENTATION?
¿QUÉ ES LA IMPLEMENTACIÓN DEL GSP?
»Monitoring groundwater conditions and use
Monitoreo de las condiciones y el uso de las aguas
subterráneas
»Annual Reports
Reportes Anuales
»Carrying out projects and management actions
Realización de proyectos y acciones de gestión
» Periodic Evaluations / GSP Updates
Evaluaciones Periódicas / Actualizaciones del GSP

MONITORING

MONITOREO
Includes:
» water levels,
» water quality,
» streamflow,
» subsidence, and
» water use
Incluye:
» los niveles de agua,
» la calidad del agua,
» el flujo de
corrientes,
» el hundimiento y
» el uso del agua

Page 2213 of 3451 ends

54 ANNUAL REPORTS

INFORMES ANUALES
55 Include:
» water level data,
» storage change,
» water use,
» sustainability progress
Incluye:
» dado de nivel de agua,
» cambio de
almacenamiento,
» el uso agua,
» progreso de la
sostenibilidad

PERIODIC EVALUATIONS /

GSP UPDATES
EVALUACIONES PERIÓDICAS /

ACTUALIZACIONES DEL GSP

Page 2214 of 3451 ends

56 DISCUSSION AND Q&A
DISCUSIÓN / PREGUNTAS Y RESPUESTAS

HOW TO STAY INVOLVED
CÓMO MANTENERSE INVOLUCRADO

Page 2215 of 3451 ends

REVIEW AND ADOPTION
REVISIÓN Y ADOPCIÓN
Late Summer 2021
Finales del verano de
2021
Draft GSP
Released
Publicación del
borrador del
GSP
Fall 2021
Otoño 2021
90 Day Public
Review Period
90 Dias Período
de revisión
pública
Winter 2021
Invierno 2021
Adoption
Hearing
Audiencia de
adopción
January 2022
Enero 2022
Final GSP Sent
to DWR
GSP final
enviado a DWR

WEBSITE

SITIO WEB

Page 2216 of 3451 ends

THANK YOU

GRACIAS

Page 2217 of 3451 ends

TEMESCAL GSA

TEMESCAL GROUNDWATER SUSTAINABILIT Y PLAN

G R O U N D W A T E R F O R P E O P L E , T H E E N V I R O N M E N T,

AND THE FUTURE
Community input is needed! We want your help to create an effective plan for the future of our groundwater. Visit CoronaCA.gov/Groundwater or send an email to [email protected] to attend a workshop or learn more! WHAT IS GROUNDWATER?
Groundwater is an important source of water stored in
the earth beneath our feet, in spaces between sand, soils, and fractured rock known as an aquifer. The areas of the most productive aquifers in California have been defined as groundwater basins, which can extend for many miles.

The Temescal Basin covers nearly 66 square miles.

T H E W AT E R B E N E AT H Y O U R F E E T

AND IN YOUR FAUCET
You may not know it, but if you live in Corona, Norco, or Home Gardens, you are likely using groundwater that comes from the Temescal Basin. Groundwater from the Temescal Basin and other local groundwater basins, along with water purchased from other areas, is treated and blended together. It then arrives as tap water at your home or business.

The groundwater beneath your feet is an important local resource that will be even more important in the future. On the other side of this factsheet, you can learn more about who manages groundwater in the Temescal Basin and how you can get involved in protecting local groundwater for your community and all who depend on it.

WHO USES GROUNDWATER?
Groundwater from aquifers is drawn out by pumps.

Cities and water districts pump groundwater from wells
to supply to businesses and homes. People in rural areas may have their own wells for personal use and/or to
water crops. Groundwater also has many uses in
manufacturing and industry. It can be used to process,
wash, cool, or transport a product.

Groundwater is important to the environment, it flows
to and from wetlands, springs, creeks, lakes, and other bodies of water. The plants and animals that live near or in these bodies of water sometimes depend on it for their survival. These areas are called Groundwater Dependent
Ecosystems.

GET
INVOLVED!
Legend
Temescal Subbasin
City of Corona
City of Norco
Home Gardens
County Water District
Norco
Corona Home
Gardens
Well
Aquifer
Groundwater
Dependent
Ecosystems

Page 2218 of 3451 ends

TEMESCAL GSA

TEMESCAL GROUNDWATER SUSTAINABILIT Y PLAN
To learn more about the TEMESCAL GROUNDWATER SUSTAINABILITY PLAN, including dates of public workshops and other ways to get involved:

Please visit CoronaCA.gov/Groundwater
Send an email to [email protected]

G R O U N D W A T E R F O R P E O P L E , T H E E N V I R O N M E N T,

AND THE FUTURE

GROUNDWATER MANAGEMENT
For many decades, the City of Corona, City of Norco,
and Home Gardens County Water District have
carefully managed groundwater in the Temescal Basin.

They have made sure that there is enough clean and
drinkable water for the communities that need it.

This has become more of a challenge due to changes
in climate, the cost of importing water, and the fact
that more water is needed because communities
are growing. To help all stewards of groundwater
plan for these changes, the state-wide Sustainable
Groundwater Management Act was passed in 2014.

The Sustainable Groundwater Management Act or
“SGMA” is a California law that gives local agencies new tools for managing groundwater and planning for the future.

The City of Corona, City of Norco, and Home Gardens County Water District have formed the Temescal Subbasin Groundwater Sustainability Agency (Temescal GSA) in order to make a Groundwater Sustainability Plan for the Temescal Basin. Since groundwater is such an important resource for everyone, we need your help!

G R O U N D W AT E R

F O R T H E F U T U R E
Important factors for groundwater
basin management can be seen
on the right. By creating a Groundwater Sustainability Plan, we will better manage the groundwater in the Temescal Basin and ensure we have enough for current and future generations. We will seek understanding of past groundwater use and plan for the sustainable use of future groundwater. Whether you own your own well, use water from the tap, irrigate your crops, or pump groundwater for your business, everyone can participate in making this plan a success! We want to hear your questions, ideas, and concerns about protecting our groundwater supply and quality in the Temescal Basin. To find out how, please visit the website at CoronaCA.gov/ Groundwater.

Lowering
GW Levels
Reduction
of Storage
Seawater
Intrusion
Degraded
Quality
Land
Subsidence
Surface Water
Depletion

Page 2219 of 3451 ends

TEMESCAL GSA

TEMESCAL GROUNDWATER SUSTAINABILIT Y PLAN
Alluval Fan
Aquifers
Alluval Fan
Aquifers
Sandstone
Aquifer
Tertiary
Aquifers
Granite
Bedrock
Channel Aquifer Temescal
Wash
Santiago
Peak
Volcanics
Silverado
Formation
Current and historical groundwater conditions give an
understanding of Basin health over time and show patterns of use that are important for understanding current and future sustainability. Groundwater conditions will be
described in terms of the six sustainability indicators shown below, which will also be used for planning for
sustainability in the Basin.

A water budget quantifies the volumes of ground and
surface water moving through a basin. It will also estimate changes in storage, a measure of how much groundwater
enters or leaves the Basin in any given period. The water budget and change in storage are important factors
in estimating sustainable yield, or how much water
can be pumped from the Basin without significant and
unreasonable impacts.

This information will provide a framework for defining
sustainability in the Temescal Basin in the context of
the six sustainability indicators shown to the left. Once sustainability is defined, we will prepare management
actions and projects to maintain sustainability into the future.

G R O U N D W A T E R F O R P E O P L E , T H E E N V I R O N M E N T,

AND THE FUTURE
Community input is needed! Visit CoronaCA.gov/Groundwater or send an email to [email protected] to attend a workshop, review draft chapters, and learn more!

HOW WE LEARN ABOUT

T H E T E M E S C A L B A S I N
A hydrogeologic conceptual model provides
a description of the physical features within a
groundwater basin. It will summarize information
about basin boundaries, soils, geologic structure, and
aquifers within the Temescal Basin. It will also illustrate where and how water flows in and through the Basin.

PREPARING TO DEFINE SUSTAINABILITY
The Temescal GSA is preparing to define groundwater sustainability for the Temescal Basin to ensure we have enough groundwater for current and future generations. First, it is important to understand more about the Basin. This fact sheet explains some important information that will be in the Temescal Groundwater Sustainability Plan to provide that understanding.

GET
INVOLVED!
To learn more
about the
Temescal GSA,
GSPs, and
groundwater
see Fact Sheet 1.

To learn more about the TEMESCAL GROUNDWATER SUSTAINABILITY PLAN, including dates of public workshops and other ways to get involved:

Please visit CoronaCA.gov/Groundwater Send an email to [email protected] Lowering
GW Levels
Reduction
of Storage
Degraded
Quality
Surface Water
Depletion
Land
Subsidence
Saltwater
Intrusion
FACT SHEET 2
This block diagram shows some important features of the Temescal Basin described in the hydrogeologic conceptual model

Page 2220 of 3451 ends

TEMESCAL GSA
PLAN DE SOSTENIBILIDAD DE AGUAS SUBTERRÁNEAS
(GSP, POR SUS SIGLAS EN INGLÉS) DE TEMESCAL
Aquíferos en
el abanico
aluvial
Aquíferos en
el abanico
aluvial
Acuífero de
areniscas
Acuífero
terciario
Lecho de
granito
Acuífero de canal Arroyo de
Temescal
Rocas
volcánicas
de
Santiago
Peak
Formación
de
Silverado
Las condiciones actuales e históricas del agua subterránea ayudan a comprender la salud de la cuenca a lo largo del tiempo y muestran patrones de uso que son importantes para entender la sostenibilidad actual y futura. Las condiciones del agua subterránea se describirán en términos de los seis indicadores de sostenibilidad que se muestran abajo, que también se utilizarán para planificar la sostenibilidad en la cuenca.

Un balance hídrico cuantifica los volúmenes de agua
subterránea y agua superficial que se desplazan a través de una cuenca. También estima los cambios en el almacenamiento, una medida de cuánta agua subterránea entra a la cuenca o sale de esta en un período determinado. El balance hídrico y el cambio en el almacenamiento son factores importantes en la estimación del rendimiento sostenible, o de cuánta agua se puede bombear desde la cuenca sin producir un
impacto significativo y poco razonable.

Esta información proporcionará un marco para definir la sostenibilidad en la cuenca de Temescal en el contexto de los seis indicadores de sostenibilidad que se muestran a la izquierda. Una vez que hayamos definido la sostenibilidad, prepararemos las acciones y los proyectos de gestión para mantener la sostenibilidad en el futuro.

A G U A S S U B T E R R Á N E A S PA R A C O N S U M O H U M A N O ,

EL MEDIO AMBIENTE Y EL FUTURO
¡Necesitamos la opinión de la comunidad! ¡Visite CoronaCA.gov/Groundwater o envíe un correo electrónico a [email protected] para asistir a un taller, revisar los borradores de los capítulos y aprender más! CÓMO OBTENEMOS INFORMACIÓN

SOBRE LA CUENCA DE TEMESCAL
Un modelo conceptual hidrogeológico brindará una
descripción de las características físicas en una cuenca de aguas subterráneas. Resumirá la información sobre los límites de la cuenca, los suelos, la estructura geológica y los acuíferos en la cuenca de Temescal. También ilustrará dónde y cómo fluye el agua hacia y a través de la cuenca.

PREPARÁNDONOS PARA DEFINIR LA SOSTENIBILIDAD
La Agencia de Sostenibilidad de Aguas Subterráneas de Temescal (Temescal GSA) se está preparando para definir la sostenibilidad de las aguas subterráneas para la cuenca de Temescal a fin de asegurarnos de tener suficiente agua subterránea para las generaciones actuales y futuras.

En primer lugar, es importante comprender más sobre la cuenca. Esta hoja de datos explica cierta información importante que se incluirá en el Plan de Sostenibilidad de Aguas Subterráneas de Temescal para ayudar a comprenderla.
¡PARTICIPE!
Para obtener más
información
sobre Temescal
GSA, el GSP y el
agua subterránea
vea la Hoja de
datos 1.

Para obtener más información sobre el PLAN DE SOSTENIBILIDAD DE AGUAS SUBTERRÁNEAS DE TEMESCAL, incluidas las fechas de los talleres públicos y otras formas de participar:

Visite CoronaCA.gov/Groundwater Envíe un correo electrónico a [email protected] HOJA DE DATOS 2
Este diagrama de bloque muestra algunas características importantes de la cuenca de Temescal descritas en el modelo conceptual hidrogeológico Bajada de los
niveles de agua
subterránea
Reducción del
almacenamiento
Degradación
de la calidad
Merma del agua
superficial
Hundimiento
de tierras
Intrusión de
agua de mar

Page 2221 of 3451 ends

Groundwater
Dependent
Ecosystems
GSPs must protect against
surface water depletion.

This is because surface
water that is connected
to groundwater is
important for groundwater
dependent ecosystems
(GDEs). GDEs can include
plants or animals that
depend on groundwater.

The Temescal Basin
includes GDEs, primarily
in the Prado Basin.

TEMESCAL GROUNDWATER SUSTAINABILIT Y PLAN

TEMESCAL GSA

GROUNDWATER FOR PEOPLE, THE ENVIRONMENT,

AND THE FUTURE
Community input is needed! Visit CoronaCA.gov/Groundwater or send an email to [email protected] to attend a workshop, review draft chapters, and learn more!

DEFINING SUSTAINABILITY AND TAKING ACTION
Now that the background information and modeling is complete, we will define groundwater sustainability for the Temescal Basin. Management actions and projects will keep us on course, so we have enough groundwater for current and future generations. This fact sheet gives more information of these important parts of the Temescal Groundwater Sustainability Plan (GSP).

GET
INVOLVED!
To learn more
about background
information
prepared for
the GSP see
Fact Sheet 2.

FACT SHEET 3

W H AT I S S U S TA I N A B I L I T Y I N A G R O U N D W AT E R S U S TA I N A B I L I T Y P L A N ?
The Temescal GSP must include an overall goal that states the desired objectives and conditions for the Temescal Basin. That goal then helps define a sustainability framework to avoid lowering groundwater levels, reduction of storage, degraded water quality, surface water depletion, and land subsidence. The framework defines the concepts below, so that we will know if action is needed to maintain sustainability:
1) Undesirable results are conditions we want to avoid in the Temescal Basin 2) Minimum thresholds set quantifiable measures for undesirable results 3) Measurable objectives establish quantifiable goals to maintain or improve groundwater conditions
H O W C A N W E M A I N TA I N S U S TA I N A B I L I T Y ? With goals defined, the next step is to meet the standards we have set! Management actions and projects help us maintain sustainability by managing the groundwater resource to avoid undesirable results. Some of the actions and projects that will be included in the GSP are already happening, some are planned and will be implemented within the next few years, and others are potential actions that will be taken in response to future changing groundwater conditions in the Temescal Basin.

Examples of Management Actions and Projects
current planned potential future
£ Groundwater treatment
£ Water Shortage
Contingency Plans
£ Water Conservation
Programs
£ Interconnected surface
water monitoring
£ Groundwater recharge
feasibility studies
£ Additional groundwater
treatment
£ Stormwater capture,
treatment, and recharge

Page 2222 of 3451 ends

Ecosistemas
dependientes del
agua subterránea
Los GSP deben proteger
contra el agotamiento de las
aguas superficiales. Esto se
debe a que el agua superficial
que está conectada al agua
subterránea es importante para
los ecosistemas dependientes
del agua subterránea (GDE,
por sus siglas en inglés). Los
GDE pueden incluir plantas o
animales que dependen del
agua subterránea. La Cuenca
de Temescal incluye GDE,
principalmente en la
Cuenca de Prado.

PLAN DE SOSTENIBILIDAD DE AGUAS SUBTERRÁNEAS
(GSP, POR SUS SIGLAS EN INGLÉS) DE TEMESCAL

GSA DE TEMESCAL
A G U A S U B T E R R Á N E A PA R A C O N S U M O H U M A N O ,

EL MEDIO AMBIENTE Y EL FUTURO
¡Necesitamos la opinión de la comunidad! Visite CoronaCA.gov/Groundwater o envíe un correo electrónico a [email protected] para asistir a un taller, revisar los borradores de los capítulos, y aprender más! DEFINIR LA SOSTENIBILIDAD Y TOMAR ACCIÓN
Ahora que la información de antecedentes y el modelado están completos, definiremos la sostenibilidad del agua subterránea para la Cuenca de Temescal. Las acciones y proyectos de gestión nos mantendrán en el rumbo, por lo que tendremos suficiente agua subterránea para las generaciones actuales y futuras. Esta hoja informativa brinda más información sobre estas partes importantes del Plan de Sostenibilidad de Aguas Subterráneas (GSP) de Temescal. ¡PARTICIPE!
Para obtener más
información sobre
la información
de antecedentes
preparada para el
GSP, consulte la
Hoja informativa 2.

HOJA INFORMATIVA 3
¿ Q U É E S L A S O S T E N I B I L I D A D E N U N P L A N D E S O S T E N I B I L I D A D D E A G U A S S U B T E R R Á N E A S ? El GSP de Temescal debe incluir una meta general que establezca los objetivos y condiciones deseados para la Cuenca de Temescal. Luego, esa meta ayuda a definir un marco de sostenibilidad para evitar la disminución de los niveles de agua subterránea, la reducción del almacenamiento, la degradación de la calidad del agua, el agotamiento de las aguas superficiales y el hundimiento de la tierra. El marco define los conceptos a continuación, de modo que sepamos si es necesario actuar para mantener la sostenibilidad:
1) Resultados indeseables son condiciones que queremos evitar en la Cuenca de Temescal 2) Umbrales mínimos establecen medidas cuantificables para resultados no deseados 3) Objetivos medibles establecen metas cuantificables para mantener o mejorar las condiciones del agua subterránea
¿ C Ó M O P O D E M O S M A N T E N E R L A S O S T E N I B I L I D A D ? Con las metas definidas, el siguiente paso es cumplir con los estándares que hemos establecido. Las acciones y proyectos de gestión nos ayudan a mantener la sostenibilidad mediante la gestión del recurso hídrico subterráneo para evitar resultados indeseables.

Algunas de las acciones y proyectos que se incluirán en el GSP ya están en marcha, algunas están planificadas y se implementarán en los próximos años, y otras son acciones potenciales que se tomarán en respuesta a las futuras condiciones cambiantes de las aguas subterráneas en la Cuenca de Temescal.

Ejemplos de acciones y proyectos de gestión
actual planeado futuro potencial
f Tratamiento de aguas
subterráneas
f Planes de contingencia
de escasez de agua
f Programas de
conservación de agua
f Monitoreo
interconectado de
aguas superficiales
f Estudios de viabilidad
de recarga de aguas
subterráneas
f Tratamiento adicional
de aguas subterráneas
f Capturar, tratar,
y recargar aguas
pluviales

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Temescal Basin GSP

APPENDIX H
Summaries of Neighboring Basin Coordination
and Community Leader Outreach Meetings

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MEETING NOTES

TEMESCAL BASIN GROUNDWATER

SUSTAINABILITY PLAN

CITY OF CORONA
DWR PLANNING GRANT NO. 4600012652
Date: November 30, 2020 Time: 1:00 to 2:00 PM
Location: Teams Web Conference Project No.: 46414
Subject: Temescal GSP Coordination with Arlington GSA - Meeting 1 Attendees: Tom Moody, Katie Hockett, Kristian Alfelor, Melissa Estrada-Maravilla - , Corona DWP, Ryan Shaw – Western / Arlington GSA, Chad Taylor, Gus Yates, and Maureen Reilly – Todd Groundwater
The City of Corona is preparing a GSP for the Temescal Basin and wants to coordinate with Arlington GSA and the work they are doing to prepare a GSP • Our coordination will largely focus on the water budget and model for Temescal • We know there is a model for Arlington that includes estimates of outflow to Temescal
• We want to start the coordination process and plan for requesting data and information from the Arlington GSA
Geoscience is Arlington GSAs consultant preparing GSP
• They are a bit overbudget, but we can request data from them as needed.

They’re using the Santa Ana River Integrated Model for the GSP and water budget.

Water budget indicates little flow out of Arlington through the Gap in the current and future periods. The flow has decreased in recent years, but not by an amount that is significant in the context of either basin’s water budget.

Willing to coordinate on outflows to some extent, but their water budget is ahead of ours and they have a small basin they feel is well defined.

They have no interconnected surface water or GDE concerns.

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• There is a small lake in the basin (Hull Lake) that may have some interconnection, but they don’t feel they have any need for criteria to address it. • Arlington is defining water level SMC’s operationally, with respect to well depths, screened intervals, pump settings, etc.

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Corona City CouncilJune 3, 2026

Corona City Council
June 3, 2026