City of Greenfield Arroyo Seco Groundwater Sustainability Agency. Meeting Agenda February 26, :00 P.M.

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1 City of Greenfield Arroyo Seco Groundwater Sustainability Agency 599 El Camino Real Greenfield, CA Meeting Agenda February 26, :00 P.M. Your courtesy is requested to help our meeting run smoothly. Please follow the following rules of conduct for public participation in the meetings: Refraining from public displays or outbursts such as unsolicited applause, comments or cheering. Any disruptive activities that substantially interfere with the ability of the Agency to carry out its meeting will not be permitted, and offenders will be requested to leave the meeting. A. CALL TO ORDER B. ROLL CALL C. PLEDGE OF ALLEGIANCE PLEASE TURN OFF CELL PHONES AND PAGERS D. PUBLIC COMMENTS FROM THE AUDIENCE REGARDING ITEMS NOT ON THE AGENDA This portion of the Agenda allows an individual the opportunity to address the Agency on any items not on closed session, consent calendar, public hearings, and agency business. Under state regulation, no action can be taken on non-agenda items, including issues raised under this agenda item. Members of the public should be aware of this when addressing the Agency regarding items not specifically referenced on the Agenda. PLEASE NOTE: For record keeping purposes and, in the event, that staff may need to contact you, we request that all speakers step up to the lectern and use the microphone, stating your name and address, which is strictly voluntary. This will then be public information. A three-minute time limit may be imposed on all speakers other than staff members.

2 Meeting Agenda February 26, 2019 E. CONSENT CALENDAR All matters listed under the Consent Calendar are considered routine and may be approved by one action of the Agency, unless a request for removal for discussion or explanation is received prior to the time Agency votes on the motion to adopt. E-1. APPROVAL of the Minutes of the January 22, 2019 Meeting of the Arroyo Seco Groundwater Sustainability Agency and Minutes of the February 12, 2019 Special Meeting of the Arroyo Seco Groundwater Sustainability Agency F. AGENCY BUSINESS F-1. RECEIVE TODD Environmental Presentation of Groundwater Sustainability Plan (GSP) Chapters 1-3 and Provide Staff Direction a. Staff Report b. Public Comments c. Agency Board - Comments / Review / Action F-2. RECEIVE Arroyo Seco Groundwater Sustainability Agency General Manager s Status Report a. Oral Report b. Public Comments c. Agency Board - Comments / Review / Action G. ADJOURNMENT In compliance with the American With Disabilities Act, if you need special assistance to participate in this meeting, please contact the City Clerk at (831) Notification 48 hours prior to the meeting will enable the City to make reasonable arrangements to ensure accessibility to the meeting (CFR ADA Title II). This agenda is duly posted outside City Hall and on the City of Greenfield web site

3 CITY OF GREENFIELD ARROYO SECO GROUNDWATER SUSTAINABILITY AGENCY MINUTES AGENCY MEETING OF JANUARY 22, 2019 ROLL CALL Present: Absent: Staff: Chair Thorp, Vice Chair Griva, Board Members Rodriguez, Martinez and Wood None Interagency Attorney Cochran, General Manager Weeks, City Clerk Rathbun PLEDGE OF ALLEGIANCE All recited the pledge of allegiance. PUBLIC COMMENTS FROM THE AUDIENCE REGARDING ITEMS NOT ON THE AGENDA No comments were received. CONSENT CALENDAR A MOTION by Vice Chair Griva, seconded by Board Member Martinez to approve the Minutes of the November 27, 2018 Meeting of the Arroyo Seco Groundwater Sustainability Agency. All in favor. Motion carried. AGENCY BUSINESS CONSIDERATION OF APPROVAL OF THE COORDINATION AGREEMENT WITH THE SALINAS VALLEY BASIN GROUNDWATER SUSTAINABILITY AGENCY (SVBGSA) Staff report was given by General Manager Weeks. John Huerta, Jr. stated that he was very impressed with the GSA and wanted to make sure that the boundaries include the City, Clark Colony and the petition lands. A MOTION by Board Member Rodriguez, seconded by Board Member Wood to approve the agreement in form and context and any significant changes would be brought back to the Board for approval. All in favor. Motion carried. RECEIVE ARROYO SECO GROUNDWATER SUSTAINABILITY AGENCY GENERAL MANAGER S STATUS REPORT Oral report was given by General Manager Weeks.

4 ASGSA Meeting January 22, 2019 Page Two General Manager Weeks asked if the regularly scheduled meeting of the advisory committee be changed to February 14 th at 9 a.m. Board concurred. General Manager Weeks updated the Board on the model for the Salinas Valley Water Basin; however, stated the model for the ASGSA was fine so the Board could move forward with the GSP. ADJOURNMENT Meeting adjourned at 4:26 p.m. Chair of the Board City Clerk of the City of Greenfield

5 CITY OF GREENFIELD ARROYO SECO GROUNDWATER SUSTAINABILITY AGENCY MINUTES AGENCY SPECIAL MEETING OF FEBRUARY 12, 2019 ROLL CALL Present: Absent: Staff: Chair Thorp, Vice Chair Griva, Board Members Rodriguez, Martinez Board Member Wood Interagency Attorney Cochran, General Manager Weeks, City Clerk Rathbun PLEDGE OF ALLEGIANCE All recited the pledge of allegiance. PUBLIC COMMENTS FROM THE AUDIENCE REGARDING ITEMS ONLY ON THE AGENDA No comments were received. ADJOURNED TO CLOSED SESSION Meeting adjourned to closed session at 5:02 p.m. CLOSED SESSION - Government Code Section CONFERENCE WITH LEGAL COUNSEL ANTICIPATED LITIGATION Significant Exposure to Litigation Pursuant to Paragraph (2) or (3) or subdivision (d) of Section : 1 case CLOSED SESSION - Government Code Section CONFERENCE WITH LEGAL COUNSEL ANTICIPATED LITIGATION Initiation of Litigation Pursuant to Paragraph (4) of Subdivision (d) of Section (Deciding Whether to Initiate Litigation): 1 case RECONVENE TO OPEN SESSION Meeting reconvened to open session at 5:24 p.m. There was no reportable action taken. ADJOURNMENT Meeting adjourned at 5:25 p.m. Chair of the Board City Clerk of the City of Greenfield

6 City of Greenfield Arroyo Seco Groundwater Sustainability Agency MEMORANDUM: February 21, 2019 AGENDA DATE: February 26, 2019 TO: FROM: TITLE: Board Members Curtis Weeks, General Manager RECEIVE TODD ENIVIRONMENTAL PRESENTATION OF GROUNDWATER SUSTAINABILITY PLAN (GSP) CHAPTERS 1-3 AND PROVIDE STAFF DIRECTION BACKGROUND TODD Environmental (TODD) has been developing the Arroyo Seco GSA (ASGSA) GSP since the summer of 2018 and presented the first GSP workshop to the Board of Directors (BOD) in November of TODD has completed draft review versions the first 3 GSP chapters for the Arroyo Seco groundwater basin. These chapters were presented to the ASGSA Advisory Committee on February 15, BUDGET DISCUSSION TODD provided the Advisory Committee a presentation focused on several key issues for the Committee. These include discussions for the following GPS components: Water Budget development Management Area considerations Minimum Threshold Criteria Groundwater elevations Groundwater Storage Seawater Intrusion Subsidence Water Quality Inter-connected Surface Water Groundwater-Dependent Ecosystems

7 Duration of low groundwater events Our current proposed methods will be to develop draft GSP chapters for the Advisory Committee to review, prior to presenting the chapters to the BOD. Public comments will be received following each presentation allowing the public to provide direct input into the GPS process. One final round of GPS comments is anticipated in the fall to allow for creating a final draft plan ready to submit to the Department of Water Resources in January of REVIEWED AND RECOMMENDED: The ASGSA General Manager and the Advisory Committee have reviewed this report and the draft GSP Chapters and recommends that the draft GPS Chapters be forwarded to the Board of Directors for their consideration.

8 Arroyo Seco Groundwater Sustainability Plan Advisory Committee Meeting February 14, 2019 Greenfield, CA

9 Agenda Comments on draft GSP Sections 1 through 3.1 Comments on draft GSP Section 3.2 Sustainability Criteria Water Levels Subsidence 2

10 GSP Chapter 1: Introduction 1.1 Purpose of the GSP 1.2 Agency Information 1.3 Organization of the GSP 3

11 GSP Chapter 2: Description of Plan Area 2.1 Jurisdictional Areas 2.2 Water Resources Monitoring and Management Programs 2.3 Land Use and Land Use Planning 4

12 5 MCWRA Water- Level Monitoring Wells

13 MCWRA pumping data are proprietary Only summary maps and tables are available to ASGSA and the public 6

14 Water Quality Monitoring Can ILRP monitoring replace MCWRA monitoring? 7

15 GSP Chapter 3: Basin Setting 3.1 Hydrogeologic Conceptual Model 3.1 Topography 3.2 Watersheds 3.3 Surficial Geology 3.4 Soils 3.5 Basin Fill Materials 3.6 Recharge Locations 3.7 Wells 8

16 9 Hydrogeologic Cross Sections

17 10 Recharge Locations: Areas, Lines and Points

18 GSP Chapter 3: Basin Setting 3.2 Historical and Current Groundwater Conditions 11 Historical conditions: Pre-dam Mostly grain and field crops Current conditions: Post-dam and partly post SRDF and BO Average rainfall Mostly vineyards, truck crops, drip irrigation Future conditions: 50-year period hydrology Current land and water use Current SVWP operation

19 Groundwater Levels Hydrographs and water-level contour maps. Nothing much new since our previous meetings. 12

20 Two Subsidence Monitoring Programs 13

21 Inter-Connected Surface Water Revised Arroyo Seco Elevation Profile 15

22 Groundwater Dependent Ecosystems Because interconnection of groundwater and surface water is plausible, there might be GDEs. Types of GDEs Vegetation Fish Key question: does groundwater pumping adversely affect GDEs? 17

23 Riparian Vegetation New Salinas River Vegetation Analysis 18

24 Fish Fisheries agencies appear primarily interested in steelhead trout migration. Potential impact of groundwater pumping deferred to Sustainability Criteria section. IF pumping depletes Salinas River flow, the effect is longer periods of reservoir release curtailment during droughts. ASGSA does not have to fix impacts resulting from pre-2014 conditions. 19

25 Sustainability Criteria Water Levels Subsidence 20

26 Minimum Threshold for Water Levels Is duration of low water levels important? Week, season, multiple years? Breaking suction or decreased gpm loss of crop? 2

27 2 Example: Well on Oak between 1 st and 2 nd Streets

28 MANAGEMENT OBJECTIVE = OPERATING RANGE Root Zone Ground Surface Example: Set Minimum Threshold between 2014 and 2015 Water Levels MINIMUM THRESHOLD 2

29 Actions Triggered by Low Water Levels What actions can well owner take? Increase pumping duration Add storage to system Install bigger pump and use gate valve when water levels are normal Install variable-frequency-drive pump Reduce irrigated area in years with curtailed reservoir releases 2

30 2 Flat pump performance curves are a major problem

31 Example performance curve In this example: 10-foot increase in depth to water 800 gpm 200 gpm 2

32 Actions Triggered by Low Water Levels What actions should ASGSA take? Prevent low water levels Percolate additional Clark Colony diversions for recharge Negotiate change in SVWP operations (e.g. SVWC litigation) Respond to low water levels Revolving fund to finance well deepening, pump lowering, pump motors, etc. 2

33 Sustainability Criteria for Subsidence Caused by compaction of clays when groundwater levels decline Elastic and inelastic components Potential impacts: Well casings protrude out of the ground Well casings collapse or deform Laser-leveled fields no longer true Ditches, canals, sewers and storm drains overflow or no longer flow at design rates Increased flooding near rivers 28

34 Current condition: 1-2 inches elastic subsidence No inelastic subsidence 29

35 Sustainability Criteria for Subsidence Minimum Threshold: undesirable results would occur if Cumulative inelastic subsidence exceeds 1 foot anywhere in ASGSA Differential subsidence alters ground slope by more than (5 feet per mile) 30

36 Sustainability Criteria for Subsidence Basis for 1-foot maximum inelastic subsidence criterion: Min. floor elevation over 100-year flood level = 1 foot Min. freeboard for road ditches = 1 foot Well casing collapse in Sacramento Valley rare where subsidence < 1 foot. 31

37 Sustainability Criteria for Subsidence Basis for ft/ft differential subsidence criterion: Min. drain slope in plumbing code = ft/ft Min. lot slope in new development = Min. sewer slope 6-inch pipe = inch pipe = Typical field slopes for surface irrigation Border = Furrow =