Groundwater Sustainability Agency

ARROYO SECO GROUNDWATER SUSTAINABILITY AGENCY ADVISORY COMMITTEE MEETING November 9, 2022 @ 1:00 P.M. Virtual Attendance Only and Remote Viewing Options The Arroyo Seco Groundwater Sustainability Agency (“ASGSA”) Advisory Committee will be conducting a meeting on November 9, 2022. Consistent with Assembly Bill (AB) 361, the Advisory Committee will hold this meeting virtually only, without in-person attendance by the public and without a physical location for public participation. Further, and consistent with AB 361, the meeting is accessible for public participation through video conferencing and livestreaming. The Board meeting to be held on November 9, 2022, at 1:00 p.m. will only be accessible online and may be viewed through the following options: Please click the link below to join the webinar: https://us02web.zoom.us/j/82173177313 Or One tap mobile: US: +16699006833,,82173177313# or +16694449171,,82173177313# Or Telephone: Dial(for higher quality, dial a number based on your current location): US: +1 669 900 6833 or +1 669 444 9171 or +1 719 359 4580 or +1 253 215 8782 or +1 346 248 7799 or +1 646 931 3860 or +1 689 278 1000 or +1 929 205 6099 or +1 301 715 8592 or +1 309 205 3325 or +1 312 626 6799 or +1 360 209 5623 or +1 386 347 5053 or +1 507 473 4847 or +1 564 217 2000 Webinar ID: 821 7317 7313 The ASGSA will provide links to these streaming options on the City of Greenfield’s website and on its Facebook page. Public Comment Public comments will be permitted in the following formats: (1) through Zoom, and (2) through e-mail. If you wish to make a public comment through Zoom, please use the “raise your hand” feature during the public comment section of the agenda that you wish to comment on. You will be selected by the meeting host and will be allowed to say your comment aloud. If you wish to make a public comment through email, please submit your public comment to cityclerk@ci.greenfield.ca.us. In the subject line of the email, please state your name and the item you are commenting on. If you wish to submit a public comment on more than one agenda item, please send a separate e-email for each item you are commenting. Please be aware that written public comments, including your name, may become public information.  ASGSA Advisory Committee Meeting Greenfield Civic Center 599 El Camino Real Greenfield, CA 93927 Meeting Agenda November 9, 2022 1:00 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. PLEASE TURN OFF CELL PHONES AND PAGERS 1. PUBLIC COMMENTS REGARDING ITEMS NOT ON THE AGENDA – A three-minute time limit may be imposed on all speakers. This portion of the Agenda allows an individual the opportunity to address the Committee on any items not on closed session, consent calendar, public hearings, and Advisory Committee 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 Committee regarding items not specifically referenced on the Agenda. PLEASE NOTE: Public comments may be made in the following formats: through Zoom or email. If you wish to make a public comment through Zoom, please use the “raise your hand” feature during the public comment section of the agenda that you wish to comment on. You will be selected by the meeting host and will be allowed to say your comment aloud. If you wish to make a public comment through email, please submit your public comment to cityclerk@ci.greenfield.ca.us. Please review the City’s Attendance and Public Comment Policy for additional information. 2. 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. a. ADOPTION of Resolution GSA #2022-02, A Resolution of the Arroyo Seco Groundwater Sustainability Agency Advisory Committee Authorizing the Continued Use of Remote Teleconferencing Provision (AB 361) b. APPROVE Minutes of the October 12, 2022 Arroyo Seco Groundwater Sustainability Agency Advisory Committee Meeting 3. REVIEW AND CONSIDERATION OF THE ARROYO SECO WATERSHED PROTECTION POLICY a. Report b. Public Comments c. Committee Board - Comments / Review / Action ASGSA Advisory Meeting Agenda Page 2 4. REVIEW AND CONSIDERATION OF THE TODD ENGINEERS DEEP AQUIFER TECHNICAL MEMORANDUM a. Report b. Public Comments c. Committee Board - Comments / Review / Action 5. GENERAL MANAGER’S REPORT 6. 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) 674-5591. Notification 48 hours prior to the meeting will enable the City to make reasonable arrangements to ensure accessibility to the meeting (CFR 35.102-35.104 ADA Title II). ********************************************************************************* This agenda is duly posted outside City Hall and on the City of Greenfield web site  RESOLUTION GSA NO. 2022-02 A RESOLUTION OF THE ARROYO SECO GROUNDWATER SUSTAINABILITY AGENCY ADVISORY COMMITTEE AUTHORIZING THE CONTINUED USE OF REMOTE TELECONFERENCING PROVISIONS (AB 361) WHEREAS, the Governing Board of the Arroyo Seco Groundwater Sustainability Agency Advisory Committee (“Governing Board”) is committed to open and transparent government, and full compliance with the Ralph M. Brown Act (“Brown Act”); and WHEREAS, the Brown Act generally requires that a public agency take certain actions in order to use teleconferencing to attend a public meeting virtually; and WHEREAS, the Governing Board recognizes that a local emergency persists due to the worldwide COVID-19 pandemic; and WHEREAS, the California Legislature has recognized the ongoing state of emergency due to the COVID-19 pandemic and has responded by creating an additional means for public meetings to be held via teleconference (inclusive of internet-based virtual meetings); and WHEREAS, on September 16, 2021, the California legislature passed Assembly Bill (“AB”) 361, which amends Government Code, section 54953 and permits a local agency to use teleconferencing to conduct its meetings in any of the following circumstances: (A) the legislative body holds a meeting during a proclaimed state of emergency, and state or local officials have imposed or recommended measures to promote social distancing; (B) the legislative body holds a meeting during a proclaimed state of emergency for the purpose of determining, by majority vote, whether as a result of the emergency, meeting in person would present imminent risks to the health or safety of attendees; or (C) the legislative body holds a meeting during a proclaimed state of emergency and has determined, by majority vote, pursuant to subparagraph (B), that, as a result of the emergency, meeting in person would present imminent risks to the health or safety of attendees; and WHEREAS, in order for the Governing Board to use teleconferencing as allowed by AB 361 after October 1, 2021, it must first adopt findings in a resolution, allowing the Governing Board to conduct teleconferenced meetings for a period of thirty (30) days; and WHEREAS, Governor Gavin Newsom declared a state of emergency for the State of California due to the COVID-19 pandemic in his order entitled “Proclamation of a State of Emergency,” signed March 4, 2020; and WHEREAS, the Governing Board previously adopted Resolution Number 2021-01 on October 26, 2021, finding that the requisite conditions exist to conduct remote teleconference meetings in accordance with Government Code section 54953(e); and WHEREAS, the Governing Board is conducting its meetings through the use of telephonic and internet-based services so that members of the public may observe and participate in meetings and offer public comment; and {SR649035}  WHEREAS, as a condition of the continued use of the provisions found in Government Code section 54953(e), the Governing Board must reconsider the circumstances of the state of emergency and find that either it continues to directly impact the ability of the members to meet safely in person, and/or state or local officials continue to impose or recommend measures to promote social distancing; and WHEREAS, the County of Monterey continues to require and/or recommend certain social distancing requirements of people within Monterey County, as described in detail in the “Recommendation Regarding Social Distancing Including Remote Meetings of Legislative Bodies,” issued by the Monterey County Health Department on September 22, 2021; and NOW THEREFORE, BE IT RESOLVED, that the recitals set forth above are true and correct and fully incorporated into this Resolution by reference. BE IT FURTHER RESOLVED, that the Governing Board has reconsidered the circumstances of the state of emergency and finds that the state of emergency continues to directly impact the ability of members to meet safely in person. BE IT FURTHER RESOLVED, that the Governing Board has determined that state or local officials have imposed or recommended social distancing measures. BE IT FURTHER RESOLVED, that the actions taken by the Governing Board through this Resolution may be applied to all District committees governed by the Brown Act unless otherwise desired by that committee. BE IT FURTHER RESOLVED, the Governing Board authorizes the General Manager or their designee(s) to take all actions necessary to continue to conduct Governing Board meetings in accordance with Government Code section 54953(e) and all other applicable provisions of the Brown Act, using teleconferencing for a period of thirty (30) days from the adoption of this Resolution, after which the Governing Board will reconsider the circumstances of the state of emergency. PASSED AND ADOPTED by the Arroyo Seco Groundwater Sustainability Agency Advisory Committee Governing Board on this 9th day of November 2022, by the following vote: AYES, and all in favor, thereof, Board Members: NOES, Board Members: ABSENT, Board Members: ABSTAIN, Board Members: ____________________________ Chair of the Board Attest: _____________________________ City Clerk of the City of Greenfield {SR649035}  Arroyo Seco River Watershed Protection Policy The Arroyo Seco Groundwater Basin is historically and currently managed as a Sustainable Groundwater Basin. WHEREAS, the Arroyo Seco Cone Management Area (ASCMA) is in the Salinas Valley in the Forebay Subbasin, and is managed by the Arroyo Seco Groundwater Sustainability Agency (“ASGSA”), as set forth in the ASGSA/SVBGSA Implementation Agreement and as outlined in Section 1.2.4.3 of the Forebay Subbasin Groundwater Sustainability Plan (GSP); and, WHEREAS, as required by the State of California’s Sustainable Groundwater Management Act (“SGMA”), the ASGSA has adopted the Forebay Subbasin GSP including the ASCMA; and, WHEREAS, the Forebay Subbasin GSP describes sustainable management criteria, and sets forth a menu of management actions that can be implemented, if needed, to maintain sustainability, by 2042 as required by SGMA, along with required GSP annual reports and updates, constituting the “sustainability program” for the Forebay Subbasin; and, WHEREAS, the ASCMA and the Forebay Subbasin receive significant direct recharge from the Arroyo Seco River as described in the Forebay Subbasin GSP in Sections 4.4.4, 4.5, 6.3.1, 6.4.2, 6.6.1 and 6.7.2 providing a sustainable source of water supply and water quality benefits from the unregulated flow of the Arroyo Seco River. Recharge from the Arroyo Seco River directly contributes to create a basin of high-quality groundwater forming the Arroyo Seco Cone Management Area (ASCMA); and, WHEREAS, the Arroyo Seco River provides the ASCMA and the much of the Salinas Valley groundwater basin significant environmental benefits to maintaining the Arroyo Seco River in a natural (unregulated) state. The Arroyo Seco River is recognized as a Class 1 Recovery stream for threatened South-Central Coast Steelhead. It is the largest unregulated tributary to the Salinas River and as a result, it has the greatest potential for sustaining steelhead populations in the Salinas River watershed; and, WHEREAS, Historic and current management and use of the waters of the Arroyo Seco River Watershed including surface water and groundwater have resulted in a Sustainable Arroyo Seco/Greenfield Groundwater Basin as detailed in Section 6.3.4 and 6.6.4 of the Forebay Subbasin GSP; and, WHEREAS, one of the key objectives of this policy is to support the unregulated flow of the Arroyo Seco River so that opportunities for steelhead recovery will not be adversely impacted, or diminished and, WHEREAS, as required by SGMA, the ASGSA has adopted the Forebay Subbasin Groundwater Sustainability Plan (GSP) including the Management Action to adopt and implement an Arroyo Seco River Watershed Protection Policy as described in Section 9.4.4 of the Forebay Subbasin GSP; and,  WHEREAS, the goal of this policy to ensure that future actions within the Arroyo Seco River Watershed will not adversely impact, change, or threaten the Sustainability of the Forebay Subbasin or the ASCMA; and, NOW THEREFORE, in consideration of the facts recited above, the ASGSA adopts the following Arroyo Seco River Watershed Protection Policy: Protection of Arroyo Seco Watershed for Compliance with the Forebay Subbasin GSP. 1) The purpose of this Policy is to protect the flow and quality of water from a non- regulated (undammed) Arroyo Seco River Watershed so that the river will recharge the ACMA, the Forebay Subbasin, and downstream Salinas Valley groundwater basins consistent with the Forebay Subbasin GSP, and support habitat for steelhead recovery in accordance with the Forebay Subbasin GSP. 2) The Arroyo Seco River Watershed means any natural or artificial watercourse, including the Arroyo Seco River, tributary creeks, ditch, channel, canal, conduit, drain, waterway, gully, ravine or arroyo or wash that contributes surface or subface water flow into Arroyo Seco River. Water flow means waters that flow towards the Arroyo Seco River. 3) In the event that any of the following actions occur, or there is the potential for them to adversely impact the sustainability of the ASCMA, the ASGSA will participate in the appropriate governmental processes in furtherance of the implementation of the Forebay Subbasin GSP and protect (or support) the character of the Arroyo Seco Watershed and the sustainability of the ASCMA and to avoid adverse impacts to it. a. Impairment, diversion, impediment or alteration of the flow of water running into and throughout the Arroyo Seco River that adversely impacts the sustainability of the ASCMA or the Forebay Subbasin in accordance with the Forebay Subbasin GSP. b. Deposition of material in the Arroyo Seco Watershed watercourses that result in flow obstructions, or impairments, diversions, impediments or alterations the characteristics of the flow of water therein. c. Alterations to the surface of land by construction, excavation, embankment or otherwise, that have the potential to alter the capacity of a watercourse or the characteristics of the flow of water therein; d. Process of new water right appropriations from the Arroyo Seco River Watershed and the Watercourses of the Arroyo Seco River which may adversely affect the sustainability of the ASCMA. PASSED AND ADOPTED, by the Arroyo Seco Groundwater Sustainability Agency Governing Board on this ____________ 2022, by the following vote: AYES, and all in favor, thereof, Board Members: NOES, Board Members: ABSENT, Board Members: ABSTAIN, Board Members: ____________________________ Chair of the Board Attest: _____________________________ City Clerk of the City of Greenfield  October 12, 2022 MEMORANDUM To: Derrik Williams, Abby Ostovar, Joe Oliver and Victoria Hermosilla, Montgomery & Associates From: Gus Yates, Senior Hydrologist Re: Extent and Definition of Deep Aquifer After participating in the October 3, 2022 Deep Aquifer workshop and re-reading the July 25, 2022 memorandum describing the Deep Aquifer, I think the proposed definition and geographic extent of the Deep Aquifer are too broad in the Seaside Basin area and the Forebay Subbasin area. The definition includes areas that are more appropriately considered adjacent to the Deep Aquifer, not within it. The historical understanding of the Deep Aquifer is a set of aquifers in the coastal area of the Salinas Valley beneath the 400- Foot Aquifer and the confining layer that underlies it. The Deep Aquifer definition presented in the memorandum and workshop is too broad and entrains areas that are not part of the Deep Aquifer. The reasons for revising the definition and footprint of the Deep Aquifer in those two areas are presented below. Seaside Basin Area The memorandum states two criteria for an area to be included in the Deep Aquifer. The first criterion states that the Deep Aquifer consists of water-bearing sediments that “are below a relatively continuous aquitard or area of higher clay content encountered between approximately 500 feet and 900 feet below land surface within the Salinas Valley Basin. The relatively continuous high-clay aquitard must furthermore be below the identified 400-Foot Aquifer, or its stratigraphic equivalent.” This definition falls apart in the Seaside Basin area for the following reasons: 1. The reference to depth below land surface is inappropriate. In the coastal part of the Salinas Valley, land surface is near sea level, and the depth below land surface is roughly the same as depth below sea level. In the Seaside Basin, Aromas and dune sands have raised the ground surface by up to 200 feet, which conceals the fact that the top of the Santa Margarita Formation is at a much higher elevation in that area than it is beneath the 400-Foot Aquifer—as little as 50 ft below sea level and not more than 500 feet below sea level, as shown in Figure 1. Attachment 1 of the July 25 memo states that the Deep Aquifer is below an aquitard that “has been defined as occurring between 500 feet and 900 feet below land surface”. This criterion is not met in the Seaside Basin. 2490 Mariner Square Loop, Suite 215 | Alameda, CA 94501 | 510 747 6920 | toddgroundwater.com  2. There is no “relatively continuous aquitard” in the Seaside Basin. The Paso Robles Formation has numerous clay layers throughout its entire depth, but none of them function as a distinct aquitard the way the clays beneath the 400-Foot Aquifer do in the Salinas Valley. 3. The 400-Foot Aquifer is not present in the Seaside Basin. Therefore, none of the aquifers are “below the identified 400-Foot Aquifer”. 4. The term “or its stratigraphic equivalent” is too broad. The Paso Robles, Purisima and Santa Margarita Formations are all present beneath the 400-Foot Aquifer in the coastal part of the Salinas Valley. That does not mean that the full extent of those formations should be considered as Deep Aquifer. The memorandum and workshop applied this inconsistently between the Paso Robles Formation and the other two formations. You argued that it would be inappropriate to include all of the Paso Robles Formation up to San Ardo within the Deep Aquifer. But you included all of the Santa Margarita formation southwest into the Seaside Basin in the Deep Aquifer. 5. By the same token, the second criterion stating that the Deep Aquifer is sediments that “are established in the Paso Robles Formation, Purisima Formation, and/or Santa Margarita Sandstone” is too broad. This criterion is also unnecessary given that these are the only significant water-bearing formations beneath the 400-Foot Aquifer in the coastal part of the Salinas Valley. Those formations collectively extend throughout most if not all of the Salinas Valley Basin, inviting inappropriate overestimation of the extent of the Deep Aquifer. Attachment 1 of the July 25 memorandum makes this exact mistake, stating globally that “The Santa Margarita Sandstone lies below the Purisima Formation, and subsequently wells completed in the Santa Margarita Sandstone are also assumed to be exclusively in the Deep Aquifers.” This statement is applied globally, regardless of whether the location in question is beneath the 400-Foot Aquifer or even within the Salinas Basin. 6. The Powerpoint presentation shown at the workshop included a hydrograph of declining water levels in monitoring well FO-7, suggesting that they were somehow related to declining water levels in Deep Aquifer wells in the coastal part of the Salinas Valley. This was extremely misleading. FO-7 is located 0.5 mile from the Paralta Well—one of the largest producers in the Seaside Basin—and similarly close to other major production wells including ASR-3 and Ord Grove 2. In contrast, the Deep Aquifer wells in Marina are 3 miles away, and ones north of the Salinas River are 7 or more miles away. Water levels in FO-7 are responding to local pumping in the Seaside Basin, not global overdraft in the Deep Aquifer far to the north. Groundwater elevation contours confirm the presence of the local pumping trough (Montgomery & Associates, 2021). Deep Aquifer Definition 2 TODD GROUNDWATER Forebay Subbasin Area The extension of the Deep Aquifer boundary up the Salinas Valley into the northern Forebay Subbasin is also not adequately supported by data. A close evaluation of well logs and the AEM data shows that the layered conceptual model of three aquifers with intervening aquicludes is rarely evident in either data set. In some cases, coarse-fine stratigraphy matches between closely-spaced wells, but in many cases it does not. Similarly, well log stratigraphy sometimes matches resistivity layering but often does not. As an example, Figure 2 shows AEM profiles along the 0-16 km segment of longitudinal flight line 103500. The AEM effort produced profiles for four stages of data reduction: resistivity, 30L sharp inversion, coarse fraction model and initial hydrostratigraphic model. They are shown for all of the flight lines in Appendices 6, 8 and 9 of the preliminary Deep Aquifer report. Those four profiles for the 0-16 km segment are placed together on Figure 2 to facilitate comparison. The patterns evident in the 30L sharp inversion profile are similar to those in the resistivity profile. The coarse fraction model and hydrostratigraphic model profiles appear to introduce additional details of layering that are presumably present in the resistivity data but simply not visible in the color-ramp plot. Overall, however, all four profiles show the same general patterns. The remaining discussion uses the resistivity profiles for illustration, but the points are valid for all four profiles. The area shown in Figure 2 is in the coastal part of the 180/400 Foot Subbasin, where those two aquifers and the Deep Aquifer should be clearly recognizable in borehole logs and the resistivity data. This is sometimes the case, but often not the case. The green circles added to the figure show locations where data are in agreement with each other and the conceptual model. That is, stratigraphy is fairly consistent among boreholes, borehole stratigraphy is consistent with resistivity, and the 180-Foot and 400-Foot aquifers are recognizable. In contrast, the red circle shows an area where borehole logs are inconsistent with each other and with resistivity, and the 180-Foot and 400-Foot aquifers are not apparent. The profile segment near the circled areas is shown at an enlarged scale in Figure 3 so that the consistencies and inconsistencies can be seen more clearly. Figure 2—and all of the profiles shown in the AEM report—reveal another significant weakness of the AEM data, which is that the 300-meter depth of investigation is too shallow to reliably detect the Deep Aquifer. The draft definition of the Deep Aquifer is sediments that are below “a relatively continuous aquitard or area of higher clay content encountered between approximately 500 feet and 900 feet below land surface”. That places the depth interval for the aquitard at 152-274 m below land surface. Thus, the depth of investigation of only 300 m (984 ft) is barely enough to encompass the aquitard much less anything below it. Farther up the Salinas Valley, the 180-Foot and 400-Foot Aquifers become increasingly less recognizable in the borehole logs and AEM data along longitudinal flight lines 103500 and 103300. Figure 4 shows the AEM resistivity profiles from 15-70 km along flight line 103500 (copied from Appendix 6 of the AEM report). The profiles are annotated by segment as to Deep Aquifer Definition 3 TODD GROUNDWATER whether the borehole logs are consistent with each other, whether the logs are consistent with AEM layering, and whether at least two aquifers with an intervening aquitard are present. If present, those could ostensibly be the 180-Foot and 400-Foot aquifers. As stated above, the 300 m depth of investigation is too shallow to discern stratigraphy below 900 feet, which is the defined depth interval for the Deep Aquifer. Two aquifers are discernible in the resistivity data along flight line kilometers 18-23 and 47- 60. This represents only one-third of the profile length shown in the figure. In the other areas, layering is either indistinct or shows only a single aquifer. Given the 23-km gap in the two-aquifer stratigraphy (the 23-47 km segment), it is unlikely that two-aquifer segments farther up the valley (i.e. segment 47-60 km) have any functional relationship to the ones farther down the valley. If the 180/400 Foot stratigraphy only extends up the valley as far as kilometer 23, that would place the end of the Deep Aquifer about midway between Spence and Chualar. Upstream of around Gonzales (kilometer 37) and especially upstream of Soledad (kilometer 48), the dominant stratigraphic pattern is a shallow coarse layer 350-500 ft thick overlying finer sediments extending down to the depth of investigation (984 ft). This layering is very different from the 180-400-Deep Aquifer conceptual model and thus does not support a conclusion that the Deep Aquifer extends this far up the valley. Along the parallel longitudinal profile (flight line 103300), the 180-400 Foot Aquifer stratigraphy breaks down around kilometer 26, about 3 km upstream of Spreckels. Some previous studies stated that a deep aquifer is present in the Forebay Subbasin, but it appears they were referring simply to a large depth of freshwater bearing sediments rather than to the Deep Aquifer with the same layering patterns that are present near the coast. For example, Montgomery-Watson (1994) stated that “this deeper aquifer consists of alternating layers of sand-gravel mixtures and clays rather than a distinct aquifer and aquitard”. Brown and Caldwell (2015) similarly said “water-bearing strata of the Forebay Subarea are unconfined and not divided into multiple aquifers.” Cross Section A-A’ in Appendix C of Brown and Caldwell (2015) also shows the 180-400 Foot Aquifer stratigraphy only up to Chualar. Revised Definition and Extent of Deep Aquifer My recommendation is to omit the words “or its stratigraphic equivalent” from part 1 of the Deep Aquifer definition because the wording is too broad and omit part 2 from the definition because it is unnecessary. The revised, more accurate definition would reduce the draft footprint of the Deep Aquifer in some areas. In the Marina-Seaside area, the revised boundary would include Marina Coast Water District’s deep wells but not be located as far south as the flow divide that defines the northern edge of the Seaside Basin. Toward the upper end of the 180/400 Foot Subbasin, the limit of the Deep Aquifer would be near Chualar. Deep Aquifer Definition 4 TODD GROUNDWATER References Cited Brown and Caldwell, Inc. January 16, 2015. State of the Salinas River Groundwater Basin. Prepared for Monterey County Water Resources Agency, Salinas, CA. Montgomery & Associates. December 31, 2021. Seaside groundwater basin 2021 seawater intrusion analysis report. Prepared for Seaside Groundwater Basin Watermaster, Monterey, CA. Montgomery Watson Consulting Engineers. 1994. Salinas River basin water resources management plan Task 1.09, Salinas Valley groundwater fFlow and quality model report. Prepared for Monterey County Water Resources Agency, Salinas, CA. Deep Aquifer Definition 5 TODD GROUNDWATER  A A' (NE) (SW) Site 7 DIW-3 FO-07 Deep 600 600 DIW-2 MW-1D EB-6 500 Seaside 4 500 MW-2D DIW-1 DIW-4 Seaside 3 400 400 300 Aromas Sand 300 200 200 100 100 # # # 0 # # # # 0 -100 Paso Robles -100 Aquifer Elevation, feet Elevation, feet -200 -200 -300 -300 -400 -400 Santa Margarita -500 -500 Aquifer -600 -600 -700 -700 -800 -800 No Data -900 Monterey -900 -1,000 Formation -1,000 -1,100 -1,100 -1,200 -1,200 -1,300 -1,300 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500 7,000 7,500 Distance Along Section Line, feet Inferred Groundwater Elevation, June 2021 0 1,000 Completed Well Scale in Feet Boring 2x Vertical Exaggeration Formation Aromas Sand Paso Robles October 2022 Figure 1 Santa Margarita Sandstone Geologic Cross Section PWM Injection Field Monterey Seaside, CA No Data  SALINAS LINE 103500 0-16 km Figure 3 Section Extent 1. Well logs not consistent with each other 2. Well logs not consistent with resistivity 3. Neither consistent with two‐aquifer stratigraphy 1. Well logs consistent with each other Path: T:\Projects\Arroyo Seco 81401\GRAPHICS\Figure 2 Sample AEM Stratigraphy Profiles_r1.ai 2. Well logs consistent with resistivity 3. Both consistent with two‐aquifer stratigraphy Figure 2 Sample AEM Stratigraphy Profiles Path: T:\Projects\Arroyo Seco 81401\GRAPHICS\Figure 3 Detailed Comparison of Borehole Logs and AEM Resistivity_r1.ai 1. Well logs not consistent with each other 2. Well logs not consistent with resistivity 3. Neither consistent with two‐aquifer stratigraphy 1. Well logs consistent with each other 2. Well logs consistent with resistivity 3. Both consistent with two‐aquifer stratigraphy Figure 3 Detailed Comparison of Borehole Logs SALINAS LINE 103500 0-16 km and AEM Resistivity  15 km 32 km SALINAS LINE 103500 15-70 km Salinas Spence Chular 1. Two‐aquifer resistivity 1. Only one resistivity aquifer 2. Logs inconsistent with each other and resistivity 2. Logs inconsistent with each other and resistivity 31 km 48 km Gonzales Soledad 1. No aquitards at all 1. Resistivity shows one aquifer over finer material 2. Logs inconsistent with each other and resistivity 2. Logs inconsistent with each other and resistivity 47 km 58 km Soledad Path: T:\Projects\Arroyo Seco 81401\GRAPHICS\Figure 4 Stratigraphic Analysis of AEM Flight Line 103500 Salinas to Greenfield_r1.ai 1. Resistivity shows two aquifers: 0‐300 ft and >400 ft. 2. Only two logs for control, but they are consistent with resistivity. 56 km 70 km Greenfield Figure 4 Stratigraphic Analysis of AEM Flight Line 103500 Salinas to Greenfield 1. Resistivity shows two aquifers: 0‐200 ft and >350 ft. 1. Resistivity shows shallow aquifer over finer material. 2. Only one log for deep control, 2. Only two logs for deep control over a 14‐km distance. inconsistent with resistivity. 3. Logs inconsistent with resistivity.