UNITED STATES DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration NATIONAL MARINE FISHERIES SERVICE West Coast Region 501 West Ocean Boulevard, Suite 4200 Long Beach, California 90802-4213

March 21, 2018

Jeff Pratt Executive Officer, Fox Canyon Groundwater Management Agency 800 South Victoria Avenue Ventura, California 93009-1610 Re: Preliminary Draft Groundwater Sustainability Plan for the Oxnard Subbasin (November 2017) Dear Mr. Pratt: Enclosed with this letter are NOAA’s National Marine Fisheries Service’s (NMFS) comments on the Preliminary Draft Groundwater Sustainability Plan for the Oxnard Subbasin (Draft Plan). The Draft Plan is intended to meet the requirement of the California Sustainability Groundwater Management Act (SGMA). The SMGA includes specific requirements to identify and consider impacts to Groundwater Dependent Ecosystems (GDE) that have significant and unreasonable adverse impacts on all recognized beneficial uses of groundwater and related surface waters (Water Section 10720). As explained more fully in the enclosure, the Draft Plan does not adequately address the recognized instream beneficial uses of the Santa Clara River, or other GDE, potentially affected by the management of groundwater within the Oxnard Subbasin. In particular, the Draft Plan does not adequately recognize or analyze the important relationship between the extensive surface diversions and groundwater recharge program within the Oxnard Subbasin, and its potential adverse effects on the federally endangered steelhead (Oncorhynchus mykiss). The reasons for these conclusions are set forth in the enclosure. NMFS recommends that the revised Draft be re-circulated to give interested parties an opportunity to review and comment on the Plan before it is finalized. NMFS appreciates the opportunity to comment regarding on the Draft Plan. If you have a question regarding this letter or enclosure, please contact Mr. Mark H. Capelli in our Santa Barbara Office (805) 963-6478 or mark.capelli@noaa.gov. Sincerely,

Anthony P. Spina Chief, Southern California Branch California Coastal Office

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cc: Mark Nordberg, CDWR

Trevor Joseph, CDWR, Senior Engineering Geologist Roy Hull, CDWR, Red Bluff

Erik Ekdahl, SWRCB, Groundwater Management Program Manager Richard Wantuck, NMFS Rick Bush, NMFS Darren Brumback, NMFS Brian Cluer, NMFS Rick Rogers, NMFS Ed Pert, CDFW

Kristal Davis-Fadtke, CDFW, Water Branch Mary Larson, CDFW

Robert Holmes, CDFW Roger Root, USFWS

Chris Dellith, USFWS Kristie Klose, USFS E. J. Remsen, The Nature Conservancy

Kimberly Prillhart, VCRMA Lynn Rodriquez, WCVC Administrative file: 10012WCR2018CC00050

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Enclosure

NOAA’s National Marine Fisheries Service’s Comments on Preliminary Draft Groundwater Sustainability Plan for the Oxnard Subbasin, Ventura County, CA

(November 2017)

March 21, 2018

Introduction NOAA’s National Marine Fisheries Service (NMFS) is responsible for protecting and conserving anadromous fish species listed under the Endangered Species Act, including endangered steelhead (Oncorhynchus mykiss) residing within the Santa Clara River watershed. NMFS listed southern California steelhead, including the populations in the Santa Clara River watershed (which includes the Oxnard Subbasin), as endangered in 1997 (62 FR 43937), and reaffirmed the endangered listing in 2006 (71 FR 5248). NMFS designated critical habitat for southern California steelhead in 2005 (70 FR 52488). This designation included the main stem of the Santa Clara River (and estuary), which traverses the Oxnard Subbasin, and upstream tributaries to the Santa Clara River (e.g., Santa Paula Creek, Sespe Creek, and Piru Creek, and Hopper Creek). Critical habitat provides: 1) freshwater spawning habitat with water quality and quantity conditions and substrate supporting spawning, incubation, and larval development, 2) freshwater rearing sites with water quality and floodplain connectivity to form and maintain physical habitat conditions and support juvenile growth and mobility, water quality and forage supporting juvenile development, and natural cover such as shade, submerged and overhanging vegetation, and 3) freshwater migration corridors free of passage obstructions to promote adult and juvenile mobility and survival. Critical habitat in the Endangered Southern California Distinct Population Segment (DPS) of Steelhead has been adversely affected by loss and modification of primary constituent elements (substrate, water quality and quantity, water temperature channel morphology and complexity, riparian vegetation, passage conditions, etc.) through activities such as groundwater extractions and related surface-water diversions (NMFS 2012). Thus many of the constituent elements of critical habitats have been significantly degraded (and in some cases lost) in ways detrimental to the biological needs of steelhead. These habitat modifications have hindered the ability of designated critical habitat to provide for the survival and ultimately recovery of the Southern California Steelhead DPS. NMFS has developed a Southern California Steelhead Recovery Plan (NMFS 2012) that provides a strategy for the recovery of the species (including a threats assessment, recovery actions, and recovery criteria). Among the threats to the steelhead habitats in the Santa Clara River watershed identified in this recovery plan are surface-water diversions for groundwater replenishment, and related groundwater extractions, to support agricultural and urban developments that utilize groundwater resources. (NMFS 2012, pp. 9-1 through 9-17.) NMFS has also recently issued a 5-Year Status Review: Summary and Evaluation of the Southern California Coast Steelhead Distinct Population Segment (NMFS 2016). This Status

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Review noted that the “. . . SWRCB generally lacks the oversight and regulatory authority over groundwater development comparable to surface water developments for out-of-stream beneficial uses, though the passage of the California Sustainable Groundwater Management Act [SGMA] in 2014 partially addresses this inadequacy for some water basins.” (p. 44). The Status Review also noted that:

“The below normal precipitation and reduced runoff has adversely affected aquatic habitat for steelhead in a variety of other ways, resulting in: 1) depleted groundwater basins which provide base flows that support critical over-summering habitat for rearing O. mykiss; 2) reduced hydrological connectivity between seasonally wet and dry stream sections in interrupted streams; 3) restricted instream movement of rearing O. mykiss; 4) delayed or reduced breaching time of sandbars at the mouth of coastal estuaries, affecting water quality, and limiting both the upstream migration of adult O. mykiss and the downstream emigration of juveniles and kelts. Riparian habitat has also been adversely affected by the reduction in groundwater levels and the reduction of surface flows, affecting water temperatures and food availability.” (p. 54).

To address the identified threats to endangered steelhead in the Santa Clara River watershed, NMFS’ Southern California Steelhead Recovery Plan identifies a number of recovery actions targeting surface diversions and groundwater extraction (NMFS 2012, p. 8-6, Table 9-7, p. 9-61). These include: SCR-SCS-4.2 Develop and implement a water management plan to identify the appropriate

diversion rates for all surface water diversions that will maintain surface flow necessary to support all O. mykiss life history stages, including adult and juvenile O. mykiss migration, and suitable spawning, incubation, and rearing habitat.

SCR-SCS-6.1 Conduct groundwater extraction analysis and assessment. Conduct hydrological

analysis to identify groundwater extraction rates, effects on the natural stream pattern (timing, duration and magnitude) of surface flows in the mainstem and tributaries, and the estuary, and effects on all O. mykiss life history stages, including adult and juvenile O. mykiss migration, spawning, incubation, and rearing habitats.

SAC-SCR-6.2 Develop and implement groundwater monitoring and management program.

Develop and implement groundwater monitoring program to guide management of groundwater extractions to ensure surface flows provide essential support for all O. mykiss life history stages, including adult and juvenile O. mykiss spawning, incubation and rearing habitats.

In addition, the Recovery Plan identified the following critical recovery action for the Santa

Clara River, which provides, in part: Implement operating criteria to ensure the pattern and magnitude of water releases, including bypass flows from diversions from Vern Freeman Diversion, Santa Felicia, Pyramid, and Castaic dams provide the essential habitat functions

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to support the life history and habitat requirements of adult and juvenile steelhead. (Table 9-2, p. 9-17).

The Santa Clara River currently supports an endangered population of steelhead that is critical to the future survival and recovery of the broader Endangered Southern California DPS of Steelhead. When analyzing impacts on steelhead or other aquatic organisms resulting from groundwater and related streamflow diversions, identifying flow levels that effectively support essential life functions of this organism is critical (Barlow and Leake 2012). Specifically, it is essential to determine what flows adequately supports adult steelhead migration during the winter and spring, and juvenile rearing year round. Without an understanding of these hydrologic/biotic relationships, a Groundwater Sustainability Plan cannot ensure that significant and unreasonable adverse impacts from groundwater depletion (and in the case of the Santa Clara River, the integrally related surface water diversion/groundwater recharge program) are avoided (California Department of Water Resources 2016, Heath 1983). Management of the groundwater of the Oxnard Subbasin can and has affected the water resources and other related natural resources throughout the Santa Clara River watershed. Extraction of groundwater from the Subbasin has lowered groundwater levels to the point of inducing seawater intrusion into the Oxnard Subbasin, eliminated artesian springs that supported a wide variety of plant and animal species, and affected surface flows that support the migrations of endangered steelhead in the Santa Clara River watershed (Stillwater Sciences 2011a, 2011b, 2007a, 2007b). The development and operation of surface water supply facilities throughout the Santa Clara River as integral components in the management of the groundwater resources of the Oxnard Subbasin has extended the effects of the groundwater management program beyond the geographic limits of the Oxnard Subbasin and the boundaries of the Fox Canyon Groundwater Management Agency (FCGMA). Facilities such as Pyramid Reservoir, Santa Felicia Dam, Piru Creek Diversion and spreading basins, and the Vern Freeman Diversion and spreading basin has profoundly altered the natural surface flow and groundwater recharge patterns in the Santa Clara River watershed, from the headwaters to the Pacific Ocean. Unless the Draft Plan is revised to reflect the operation of these integral components of the groundwater management of the Oxnard Subbasin, the future adopted Plan will be unable to meet the requirement of SGMA to explicitly provide for the protection of habitats, including those recognized instream beneficial uses that are dependent on groundwater such as fish migration, spawning and rearing, as well as other Groundwater Dependent Ecosystems GDE. Steelhead Life History, Habitat Requirements While adult steelhead spend a majority of their adult life in the marine environment, much of this species life history phase (migration to and from spawning areas, spawning, incubation of eggs and the rearing of juveniles) occurs in the freshwater environment, including in the main stem and tributaries such as those in the Santa Clara River System. Many of the natural limiting factors (such as seasonal variation in rainfall, runoff, and ambient air and water temperatures) are exacerbated by the artificial modification of these freshwater habitats. This includes both surface

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and sub-surface extractions which lower the water table and can, in turn, affect the timing, duration, and magnitude of surface flows essential for steelhead migration, spawning and rearing. In southern California restraints on the seasonal volitional migration of steelhead between the ocean and upstream spawning and rearing areas, annual emigration of smolts and kelts, and seasonal movement of rearing juveniles within the watersheds as instream conditions vary, and can prevent the species from completing its life cycle. In particular, warm, rain-free summers require that juvenile steelhead spend rearing time in sections of the stream network that do not desiccated or overheat beyond thermal-tolerance levels. The over-summering period can be challenging to juvenile steelhead survival and growth. Lowered water tables during the dry season can indirectly affect rearing individuals by reducing vegetative cover, and directly by reducing or eliminating the summertime surface flows in parts of the watershed. On the other hand, high groundwater elevations can affect the timing, duration, and magnitude of surface flows with alluvial hydrologically connected to groundwater pumping (Barlow and Leake 2012, Heath 1983). Groundwater inputs to surface flows can buffer daily temperature fluctuations in a stream (Hebert 2016, Barlow and Leake 2012, Brunke et al. 1996, Heath 1983). Artificially reducing the groundwater inputs would likely expand or shrink the amount of fish habitat and feeding opportunities for rearing juvenile steelhead, and reduce opportunities for juveniles to successfully emigrate to the estuary and the ocean (CBCE and Podlech 2015, Croyle 2009, Glasser et al. 2007, Sophocleous 2002, Fetter 1997, CBCE and Podlech 2015). Low summer baseflow, likely caused by both surface water diversions and pumping hydraulically connected groundwater, is noted as a significant stress to steelhead survival in the Santa Clara River and tributaries (NMFS 2012, p. 9-15, Table 9-2). Specific Comments The following specific comments on the Draft Plan are arranged by page and paragraph number. 1.2.4 Operational Flexibility Limitations Page 1-17, 2nd paragraph The Draft Plan notes that the “operational flexibility” of the United Water Conservation Districts (UWCD) Vern Freeman a Diversion “is currently threatened by a reduction in diversions to comply with habitat requirements in the Santa Clara River.” NMFS’ administrative record for this diversion indicates that the statement is inaccurate for characterizing the current operations of the Vern Freeman diversion (NMFS 2008). UWCD is in the process of preparing a Habitat Conservation Plan under Section 10 of the ESA for the operation of the Vern Freeman Diversion and related water supply facilities, but this plan has not been completed. 1.2.5 Existing Conjunctive- Programs Pages 1-18 through 1-19, paragraphs 1st and 2nd

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The Draft Plan identifies the UWCD Vern Freeman Diversion project as critical component within the Oxnard Subbasin, which diverts on average over 62,000 acre-feet per year (AFY) from the main stem of the Santa Clara River. Approximately 75% of this diverted water is routed to spreading basin with the Oxnard Forebay, at the El Rio spreading basins. However, the Draft Plan does not, but should, adequately recognize and describe the relationship between the surface water diversions made at UWCD’s Vern Freeman Diversion (and the related groundwater recharge operations at the El Rio spreading basins) and the groundwater extraction activities in the Oxnard Subbasin. In this regard, diversion of surface water is undertaken for the sole purpose of combating the effects of groundwater pumping on the underground aquifer. Unfortunately, the past and ongoing diversion operations at the Vern Freeman Diversion have a number of adverse impacts on the aquatic environment and water-dependent species, including endangered steelhead. These effects include, but are not limited to, modification of the timing, duration, level, and rate of change of flow downstream of the diversion dam which affects fish passage through the lower river system, including the timing and during of the breaching of the sandbar at the mouth of the Santa Clara, and water levels and conditions in the Santa Clara River estuary (CNCE and Podlech 2015, NMFS 2012, Stillwater 2011a, 2011c, 2007a, 2007b). Because current groundwater-management activities entail United’s diversion operations at the Vern Freeman Diversion, and the related impacts on endangered adult and juvenile steelhead, these activities should be explicitly addressed in the revised Draft Plan. (For a fuller description of the effects of the Vern Freeman Diversion on the steelhead resources of the Santa Clara River see NMFS biological opinion for the Vern Freeman Diversion (NMFS 2008). 1.3.2 Summary of Beneficial Uses and Users Page 1-34, 1st paragraph The Draft Plan refers to “property interests potentially affected by the use of groundwater.” It is not clear why a distinction is made between all the recognized beneficial uses of water and those associated solely with property interests. Beneficial uses of water are usefructory uses, not fee title uses. Also, environmental uses, are not limited to a set of sub-beneficiaries of the waters of the Santa Clara River, but include the public as a whole. Page 1-36, 1st and 2nd paragraphs Environmental Users. The Draft Plan indicates that the FCGMA has taken steps to incorporate the interest of environmental users via the environmental representatives on the Technical Advisory Group (TAG), and “several non-governmental organizations with missions associated with the environmental water uses . . .” The beneficiaries of the various non-consumptive beneficial uses of the surface and groundwater resources of the Santa Clara River watershed, including the area covered by the Draft Plan, identified in the Los Angeles Regional Water Quality Control Board’s Water Quality Control Plan, include many members of the general public not represented by the members of the TAG, or the several non-governmental organizations with specific missions associated with environmental water uses. Additionally, there are several state and federal agencies with public trust responsibilities associated with the beneficial uses of the waters of the Santa Clara River watershed, including the area covered

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and/or affected by the Draft Plan. These include, but are not limited to, the California Department of Fish and Wildlife, California Department of Parks and Recreation, the U.S. Fish and Wildlife Service, and the U.S. Forest Service, and the National Marine Fisheries Service. The Federal Government. In addition to the U.S. Navy, other federal agencies have responsibility for protecting and management natural resources associated with and dependent upon the management of the surface and groundwater resources of the Santa Clara River watershed, including the area covered and/or affected by the Draft Plan. These agencies include, but are not limited to, U.S. Fish and Wildlife Service, and the U.S. Forest Service, and the National Marine Fisheries Service. 2.1 Introduction to Basin Setting Page 2-12, 1st paragraph Fox Canyon Aquifer. It is not clear what the phrase “a water-bearing deposit of the FCA fine toward the west (Turner 1975)” is referring to. This language should be clarified in the revised Plan. 2.3.1 Groundwater Elevation Data Page 2-14, 4th paragraph The Draft Plan notes that climate cycles, management actions and construction of water conservation facilities (such as the Vern Freeman Diversion) have impacted water elevations in the Oxnard Subbasin. Of particular concern to NMFS is the relationship of groundwater-management activities and bypass flows at the Vern Freeman Diversion, and their effects on the conservation of endangered steelhead. The revised Draft Plan should explicitly address the relationship between the management of the groundwater basin (including diversions and recharge operations) and their effects on surface flows (Glasser et al. 2007, Heath 1983). See additional comments below on this topic. 2.3.1.1 Oxnard Aquifer Page 2-15, 1st through 5th paragraphs Spring and Fall 2015 Groundwater Elevations. The Draft Plan provides data on fluctuations in the groundwater elevations in the Oxnard Aquifer for the Spring and Fall of 2015, but notes that there is uncertainty (particularly in the southern portion of the Oxnard Subbasin) regarding hydraulic gradient, flow direction, and groundwater elevation. The groundwater monitoring network of piezometers should be expanded to better characterize the groundwater-surface water interactions. The potential value of these data is further limited by the lack of historic groundwater-well data to provide perspective.

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Page 2-16, 4th paragraph Vertical Gradients. The Draft Plan notes that “The vertical gradient in the Forebay was high in the spring because of surface water spreading grounds in the Forebay are primarily utilized during periods of high flow in the Santa Clara River.” This conclusion is not supported by the elevations presented (Table2-2, Vertical Gradient), which are negative. Furthermore, the Draft Plan gives no indication how this condition may or may not affect surface flow levels in the Santa Clara River, or other GDE. Removal of water from the stream for recharge of the deeper groundwater subbasin has the potential to adversely affect such stream flow and related instream beneficial uses, including but not limited to support for the endangered Southern California Steelhead DPS. 2.3.6 Groundwater-Surface Water Connections Page 2-43, 1st paragraph The Draft Plan indicates that the Santa Clara River “may have a connection to the semi-perched aquifer in the Oxnard Subbasin. However, Figure 2-3 shows no clay or other low permeable sediments between the bed of the Santa Clara River and the semi-perched aquifer (see also comment below regarding “leakage”). The Draft Plan also notes that “groundwater elevation data for the semi-perched aquifers is extremely limited, with no monitoring well site near enough to surface water bodies to establish the extent of the connection between these surface waters bodies and underlying groundwater.” In light of the limited data, rather than using the phrase “may have a connection” it would perhaps be best to describe this connection as “poorly understood” (or similar phrase). It should also be noted that the water level of perched groundwater varies with time, and this can influence the connection between groundwater and surface water interactions, particularly if groundwater extractions lower the groundwater table (Glasser et al., 2007, Heath 1983). See additional comments below on this topic. Page 2-43, 2nd paragraph The Draft Plan notes that UWCD reports “stream leakage” from the Santa Clara River and Calleguas Creek into the underlying semi-perched aquifer.” This observation is not consistent with the characterization “may have a connection to semi-perched aquifer” or the depiction of the groundwater cross-section in Table 2-3 noted above. Also, the term “leakage” is not a technical term and suggests an undesirable, preventable loss, and is not an appropriate synonym for “stream seepage”, which is the more commonly used term for the geo-hydrological process that is being described (Glaser et al. 2007, Heath 1983). The revised Plan should use this terminology. Page 2-43, 3rd paragraph The Draft Plan notes that the Santa Clara River “had a net recharge to groundwater in 25 of 30 years, with an average net recharge to groundwater of c. 13,000 AFY. This recorded recharge demonstrates the connection between the Santa Clara River underlying groundwater aquifers, including semi-perched aquifers. What is unclear is how this recharge is affected by the

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condition of the groundwater levels in these groundwater basins, and the how the groundwater levels affect the surface flow patterns in the Santa Clara River (or other surface watercourses or surface water bodies) with the area covered by the Draft Plan. The revised Plan should clearly and accurately disclose this information. 2.3.7 Groundwater Dependent Ecosystems Page 2-44, 1st paragraph The Draft Plan refers to the six potential groundwater GDE units identified in Appendix I, TNC 2017, and Figure 2. Yet, this reference is unclear. Appendix “I” is titled “Preliminary Evaluation of Impacts of Potential Groundwater Sustainability Indicators on Future Groundwater Extraction Rages – Oxnard Plan and Pleasant Valley Groundwater Basins” and does not identify GDE units. However, Appendix “H” is titled “Technical memorandum – Draft Assessment of Groundwater Dependent Ecosystems for the Oxnard Subbasin Groundwater Sustainability Plan” (2017), and does identify GDE units in Figure 1. Figure 4 in Appendix H only identifies the lower Santa Clara River from El Rio west as “connected to an aquifer” with the remaining part of the river to the east to Saticoy as “not connected to an aquifer”. However, the Santa Clara River along its entire reach is always connected to an aquifer because it either receives water from the surrounding sediments or supplies water to the surrounding sediments, or both. In some reaches the river is gaining (receiving water from the aquifer) in others it is losing (supplying water to the aquifer). The Santa Clara River east of El Rio should therefore be considered connected to the aquifer, contrary to the characterization in Appendix H. See additional comments below on this topic. Of more fundamental concern is the method used by The Nature Conservancy in identifying GDE. The GDE are based on statewide data on “vegetation known to use groundwater”, and therefore does not reflect the uses made of groundwater by other biological resources, such as seasonal migration of fishes, or other organisms such as invertebrates that have differing life-cycle than plants (TNS 2018, 2017). In addition to supplying water to the root zone of plants, groundwater can also contribute to surface flows, influencing the timing, duration, and magnitude of surface flows, particularly base flows. These base flows provide essential support to aquatic invertebrates, avian fauna, and fish species, including native resident and anadromous fishes. Also, groundwater that only seasonally supports surface flows can contribute to the life-cycle of migratory fishes, such as steelhead, that can make use of intermittent flows for both migration, spawning and rearing. As a result of this limited, vegetative-centric approach to identifying and delineating GDE, the lower Santa Clara River above Highway 101 in the Forebay was removed as a potential GDE. Fora number of reasons, we believe the Technical Memorandum prepared by the Nature Conservancy, upon which this decision was based, contains a flawed analysis and a number of unwarranted assumptions (TNC 2018, 2017). First, the analysis notes the Forebay lacks a confining cap and does not have the overlying semi-perched aquifer; and as consequence, the groundwater elevations do not support a GDE as defined by the TNCs methodology. However, this methodology is focused exclusively on “vegetative known to use groundwater” (p. 2). This analysis ignores the seasonal variation in the groundwater levels in the Forebay that can periodically (seasonally, or intra-annually) support

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surface flows by affecting their timing duration and magnitude. While these groundwater-influenced flows may not be sufficient to support permanent vegetative cover, they can nevertheless support seasonal use of this reach of the Santa Clara River for migratory or rearing purposes, depending on the amount and timing of annual rainfall and runoff and the groundwater elevation. (For a study of the role of intermittent flows in the rearing phase of O. mykiss, see Boughton et al. 2009.) Second, the analysis notes that “The Santa Clara River upstream of Highway 101 has always been intermittent, and the river is a losing reach given the deeper groundwater levels. Due to the lack of groundwater-fed summer baseflow, there has historically been a corresponding lack of riparian vegetation” (pp 2-3). This statement is apparently based on an historic vegetative analysis contained in a study of the Santa Clara River (Beller et al 2011), and only reflects the presence of persistent vegetation that was mapped or described by observers at the time; it does not reflect that actual condition of seasonal flows in this reach of the Santa Clara River. The TNC study also notes that “Under current conditions, assessment of the depth to groundwater along this portion of the Santa Clara indicates that the groundwater levels are quite variable, ranging between 10 and 115 feet below ground surface, with shallower groundwater levels typically associated with wetter years followed by multiple years of much deeper groundwater level” (p 3). The TNC study concludes “Thus, the variable, deep groundwater levels and the sparse riparian vegetation in the channel typical of this reach led to the conclusion of the lack of groundwater connection to this stretch of the Santa Clara River riparian habitat” (p. 3). As noted above, the Santa Clara River along its entire reach is always connected to an aquifer because it either receives water from the surrounding sediments or supplies water to the surrounding sediments, or both. It is also important to recognize that the TNC assessment of groundwater water conditions reflects conditions that have been and continue to be significantly influenced by extensive water developments within the Santa Clara River watershed, including extensive water diversion and groundwater pumping programs (e.g., Pyramid, Santa Felecia, Castaic, and Vern Freeman dams); these activities have affected groundwater levels and related surface flows within the Oxnard Subbasin (Stillwater 2011a). As a consequence, the current conditions described in the TNS study and reflected in the Draft Plan do not represent the unimpaired groundwater elevations or surface flow conditions with the area of the Forebay. This is an example of what is often referred at a shifting base-line syndrome, mistaking current, highly modified conditions as representing past or natural conditions (See for example, Jackson et al. 2011, Pauly 1995, Wohl 2004, 2001). The past or ongoing effects of anthropogenic activities should not preclude or significantly delay the capacity of the aquatic environment to develop or maintain essential physical or biological features that species rely upon for growth and survival, otherwise the Draft Plan would not be consistent with the sustainability requirements of SGMA. Page 2-45, 1st paragraph The Draft Plan notes that “Groundwater elevation in the vicinity of these units [i.e., Revlon Slough and Lower Calleguas Creek] will be required in order to confirm whether or not the habitat is supported by groundwater.” However the Draft Plan does not, but should, propose groundwater monitoring wells in all areas where groundwater has the potential to influence

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recognized beneficial uses associated with surface flows along the Santa Clara River. See additional comments below on this topic. Lower Santa Clara River GDE Page 2-45, 1st paragraph

The Draft Plan describes the GDE of the lower Santa Clara River as being “located downstream of Highway 101 and upstream of the estuary.” The geographic scope of this GED does not adequately recognize the potential role of groundwater in the estuary or along the remainder of the Santa Clara River west of Highway 101, or the influence of groundwater elevations in this area on the life-cycle of steelhead, including their migratory, spawning and rearing phases (CEBEC and Podlech 2015). The Santa Clara estuary is known to support rearing juvenile steelhead (Kelley 2008), which have the potential for accelerated growth because of the abundance of food sources in the estuary; this accelerated growth prior to entering the ocean has been show to increase ocean survival and growth (Hayes, et al. 2008, Bond 2006).

The Draft Plan does not, but should, address the Santa Clara River estuary. Presumably because it is in the Mound Basin (though the boundaries of this basin are not delineated in Figure 1-1). However, the necessity of addressing the estuary is corroborated through studies that indicate the Santa Clara River estuary is hydrologically connected to the upper aquifers within the Oxnard Subbasin (whether semi-perched, or simply shallow groundwater aquifers). According to a water balance assessment conducted by Stillwater Sciences (2011a, 2011b) for the fall/winter period of 2010, “groundwater was estimated to contribute approximately 15% of the inflow volume . . .” For the summer/spring 2010 period “the groundwater contribution was estimated at 10 percent . . .”. The Stillwater study also indicates that in the “Santa Clara River reach upstream of the estuary, groundwater provides the dry summer baseflow, if it exists, and is a quarter of the winter flow, based on the 2010 water year assessment.” (TNC 2017, pp. 3-4). As noted above, the current conditions described in the TNS study and reflected in the Draft Plan do not represent the unimpaired groundwater elevations or surface flow conditions with the area of the Forebay. Groundwater (whether semi-perched, or simply shallow groundwater aquifers) can also contribute to surface flows, influencing in the timing, duration, and magnitude of surface flows, particularly base flows. Groundwater that only seasonally supports surface flows can also contribute to the life-cycle of migratory fishes, such as steelhead, that can make use of intermittent flows for both migration and rearing.

Both the Santa Clara River estuary and the portion of the Santa Clara River upstream of Highway 101 within the boundaries of the Oxnard Subbasin should be included in the revised Draft Plan. Further, because groundwater-management activities involve the UWCD’s diversion operations at the Vern Freeman Diversion, the relationship between these diversion activities and groundwater elevations along the affected portion of the Santa Clara River (and estuary) should be addressed in the revised Draft Plan.

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Page 2-45, 2nd paragraph The Draft Plan notes that the flow in the lower Santa Clara River (i.e., below U.S. 101) has historically been perennial, supported by groundwater during the summer months. It should be recognized that this is not the only reach of the Santa Clara River that has supported (and in most years still supports) perennial flow; the reaches between the Piru and Fillmore narrows also exhibits perennial surface flow, supported by groundwater where unconsolidated sediment deposits in combination with subsurface bedrock formations causes groundwater to rise to the surface, depending on groundwater elevations and surface flows (Stillwater Sciences 2007a, 2011a and Kennedy/Jenks 2008.) Pages 2-48 through 2-49 Table 2-6 Ecological Assets. As noted the boundaries of the “Lower Santa Clara River” do not, but should, capture the potential full extent of the GDE of the Santa Clara River. Specifically, the geographic scope of this GDE does not adequately recognize the potential role of groundwater along the remainder of the Santa Clara River west of Highway 101, or the influence of groundwater elevation in this area on the life cycle of steelhead, including their migratory, spawning and rearing phases. Regarding Ecological Assets, the Draft Plan noted the presence of steelhead critical habitat, and other state or federally protected species, but should also include Pacific lamprey (Entosphenus tridentatus) among the migratory fishes utilizing the surface flows of the Santa Clara River watershed (Booth 2017, Reid and Goodman 2016, Reid 2014, and Chase 2001). 2.4 Water Budget Page 2-51, 1st paragraph The Draft Plan should include as part of its water-budget analysis the operations of the Vern Freeman Diversion. Groundwater-management activities include substantial diversion of surface water at the Vern Freeman Diversion and subsequent retention of these waters for percolation into the groundwater at the UWCD’s El Rio Recharge Basin. These operations have the potential to impact endangered adult and juvenile steelhead. The relationship of groundwater management activities (including both recharge and groundwater extraction activities) and the effects of the related Vern Freeman Diversion on surface flows below the diversion and the maintenance of surface flows supported by groundwater should be explicitly addressed and disclosed in the revised Plan. See additional comments below on this topic. 2.4.1. Sources of Water Supply Page 2-51, 2nd paragraph As noted above, the Draft Plan referred to hydrologic connection between the Santa Clara River and the underlying semi-perched aquifer in the Oxnard Subbasin as “leakage”; here the hydrologic connection is referred to as “seepage”.

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Page 2-52, 3rd full paragraph The Draft Plan provides quantitative data for the amount of groundwater that is used for out-of-stream, consumptive uses. Groundwater to support instream, non-consumptive beneficial uses should be explicitly recognized here, as elsewhere in the revised Draft Plan, and the amount of groundwater which supports these beneficial uses should be identified, in the same manner as out-of-stream consumptive beneficial uses. If this is not known at this time, this should be acknowledged, and a method identified for providing data for this important use of groundwater. Additionally, any groundwater-extraction scheme must consider its effects on instream non-consumptive beneficial uses. 2.4.1.1 Surface Waters Pages 2-52 through 2-53, 1st subparagraph The Draft Plan notes that “The Santa Clara River is thought to have significant interactions with the groundwater system in the Oxnard Subbasin.” And further that “Climatic and basin characteristics of the Santa Clara River watershed result in an intermittent flow regime. . .” but “may have periods of continuous surface flow to the Pacific ocean generated from storm events.” We would note that the amount and extent of surface flow, particularly at critical riffle areas, along the main stem of the Santa Clara River can also be influenced by groundwater pumping (and the consequent lowering of the groundwater elevations), in two ways: 1) through removal of groundwater in areas where there is a direct groundwater-surface water connections, either by pumping or tile drains; and 2) through groundwater pumping which increases the groundwater storage and potential of increased surface water diversions for groundwater recharge. Unless the related groundwater-management activities (pumping and water diversions for groundwater recharge) are adequately considered, the effects of groundwater pumping has the potential to preclude or influence the efficacy of conservation measures within the Santa Clara River watershed for the endangered Southern California Steelhead DPS. Because the FCGMA may engage in activities, through implementation of the Plan, that ultimately affect endangered steelhead or habitat for this species, they may wish to consider obtaining an U.S. Endangered Species Act (ESA) Section 10 permit. Page 2-53, 1st paragraph The Draft Plan notes that “UWCD diverts surface water from the Santa Clara River in the Santa Paula Basin, just upstream of the Oxnard Forebay and the Mound Basin.” As noted above, unless the related groundwater-management activities (pumping and water diversions for groundwater recharge) are adequately considered, the effects of groundwater pumping has the potential to preclude or influence the efficacy of conservation measures within the Santa Clara River watershed for the endangered Southern California Steelhead DPS. These groundwater-management activities pursuant to the requirements of SGMA must explicitly provide for the protection of habitats, including those recognized instream beneficial uses which are dependent on groundwater such as fish migration, spawning and rearing, as well as other GDE. Our review indicates the Draft Plan lacks the necessary provisions to ensure habitats for water-dependent organisms are adequately protected, in accordance with the SGMA.

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2.4.1.2 Groundwater Pumping Pages 2-54 through 2-55, 1st and 2nd paragraphs The historical volumes of groundwater pumping during the 31-year period set forth in Table 2-11, while providing an important pumping record, are limited in two important ways. First, because the record extends only from 1985 through 2015, a longer-term record of pumping in the Oxnard Subbasin and meaningful historical perspective to assess historic groundwater levels are not provided. This limitation should be explicitly recognized and disclosed in the revised Plan. Second, because not all groundwater wells are metered, the record captures only a part of the actual pumping activities within the Oxnard Subbasin. As a result the data presented in Table 2-11 represent an underestimate of the true pumping and are conservative. In presenting these data, it would be important to note this limitation, and if possible to provide some estimate of the number and volume of pumpage from the unmetered groundwater wells. In the future, all wells in the FCGMA jurisdiction should be metered, and those that are not the FCGMA should estimate annual production by indirect methods (e.g., crop acreage served, etc.). See additional comments below on this topic. 2.4.2 Current and Historical Water Budget Analysis Pages 2-55 through 2-56, 1st and 2nd paragraph The Draft Plan identifies two models methods to evaluate the current and historical Oxnard Subbasin groundwater budget; both of these models focus on recharge, groundwater levels, and out-of-stream consumptive beneficial use of the groundwater of the Oxnard Subbasin. They do not explicitly take into account the influence of these groundwater-management activities on surface flows in the Santa Clara River (and estuary). As noted, the Draft Plan should include as part of its water budget analysis the operations of the Vern Freeman Diversion, which is known to impact endangered adult and juvenile steelhead. The relationship of groundwater-management activities (including both recharge and groundwater extraction activities) and the effects of the related Vern Freeman Diversion on surface flows supported by groundwater should be explicitly disclosed in the revised Plan. 2.4.2.1 Changes in Groundwater in Storage Page 2-56, 1st, 2nd paragraphs The Draft Plan asserts that changes in groundwater storage can be estimate by calculating yearly groundwater inflows and outflows from the “water budget components”. The water-budget components should include groundwater supported surface flows to sustain recognized instream beneficial uses (i.e., cold freshwater habitat, fish migration, and fish spawning), as well as other GDE. As noted above, these components do not seem to be explicitly recognized and captured in the groundwater budget models. One of the most effective and efficient way to assess the changes in annual groundwater storage is through measurement of water levels in a network of piezometers throughout the groundwater subbasin (Glasser et al, 2007, Heath 1980, Mercer and Faust 1980).

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2.4.2.3 Percolation of Agricultural Irrigation Water (Agricultural Return Flows) Page 2-59, 1st paragraph The Draft Plan notes that groundwater levels in the semi-perched aquifers within the Oxnard Subbasin could be discharged (i.e., lowered) by tile drains if the groundwater levels increase in the groundwater model. This groundwater-management activity has the potential to adversely impact instream beneficial uses, including fish migration, spawning and rearing, as well as other GDE. The discharge of tile drained water to artificial ditches interferes with the natural aquifer-surface flow interactions. The effect should be assessed and appropriate measures identified to eliminate, reduce, or mitigate these effects on GDE. 2.4.2.5 Surface Water Recharge through Streambeds Page 2-60, 1st paragraph The Draft Plan notes that the UWCD’s groundwater model uses MODFLOW STR stream package to stimulated stream flow recharge of groundwater. The MODFLOW STR model can also be changed to predict how a pumping scheme would affect aquifer-surface flow interactions under various scenarios of natural or artificial aquifer recharge. In principle, this model can be used to model the role of groundwater to support stream flow or other GDE, but its predictability must be subjected to appropriate field monitoring and testing. 2.4.2.10 Tile Drain Recharge Losses Page 2-62, 1st paragraph The Draft Plan notes that the average annual loss of shallow groundwater due to tile drains is 17,045 AFY. This groundwater is discharged to local drainage ditches and then to surface water bodies such as Revlon Slough and Calleguas Creek. It is unclear how and to what extent these tile drains effect other surface water bodies such as the Santa Clara River (and estuary) and other GDE. For this reason, we recommend the potential effects of these tile drains on base and low flows in the Santa Clara River be evaluated and groundwater-management strategies developed to eliminate, reduce, or otherwise mitigate this management of shallow groundwater conditions. As noted above, however, the discharge of tile-drained water to artificial ditches interferes with the natural aquifer-surface flow interactions, affecting the time and magnitude of natural baseflow. 2.4.3. Current (2015) Oxnard Subbasin Conditions Page 2-62, 1st and 2nd paragraphs

Regarding the requirements and standards of the SGMA legislation and SGMA regulations, it should be noted that avoiding undesirable results, includes impacts to groundwater dependent ecosystems that have significant and unreasonable adverse impacts on all recognized beneficial uses of groundwater and related surface waters (Water Section 10720). The Draft Plan notes that “these objectives are generally groundwater elevations or groundwater quality” in effect using groundwater elevations per se as a measure for identifying minimum numeric thresholds.

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However, using groundwater elevations by themselves, without characterizing the relationship between groundwater elevations and surface flows or surface water elevations, and how this relationship translates into habitat quality and availability for water-dependent organisms, will not allow FCGMA to identify minimum numeric thresholds for each sustainability indicator. In particular the Draft Plan does not, but should, adequately recognize or analyze the relationship between the extensive surface diversions and groundwater recharge program within the Oxnard Subbasin, and its potential adverse effects on water-dependent habitats and species, including the federally listed endangered Southern California Steelhead DPS. UWCD’s groundwater model has the potential to assess the relationship between groundwater storage, groundwater levels, groundwater extractions, and aquifer-surface flow interactions; this assessment can be supplemented by field measures. However, because groundwater-management activities involve the UWCD’s diversion operations at the Vern Freeman Diversion, the relationship between these activities and groundwater elevations along the affected portion of the Santa Clara River (and estuary) should also be addressed in the revised Draft Plan. Page 2-62, 3rd paragraph The Draft Plan acknowledges that groundwater outflows (i.e., extraction) are greater than inflows (including both natural and artificial groundwater recharge) and that the change in groundwater storage is actually underestimated due to seawater intrusion. Because the changes in groundwater storage and related effects are not fully realized, the implications for maintenance of aquatic and riparian surface water habitat, including all GDE and potential adverse effects on the federally listed endangered Southern California Steelhead DPS, are not adequately addressed in the Draft Plan, but should be, in accordance with the SGMA. Page 2-63, 2nd paragraph The Draft Plan notes that “groundwater recharge to the Oxnard Subbasin has been highly dependent on UWCD’s Vern Freeman Diversion for groundwater spreading, and to a lesser extent for surface water delivery to agricultural and M&I [Municipal and Industrial] users.” However, it also notes that UWCD’s water diversion at the Vern Freeman Diversion during many years between 1985 and 2015 have been larger than the average groundwater extraction, from between 78,000 and 82,000 AFY. This statement appears to suggest that a considerable amount of surface diverted water is not dedicated to groundwater recharge of the Oxnard Subbasin, but is delivered directly to agricultural and Municipal and Industrial users, which is consistent with information provided by from UWCD. 2.4.3.2 Estimates of Sustainable Yield Page 2-63, 1st and 2nd paragraph The historical estimates for the Oxnard Subbasin sustainable yield do not, but should, include groundwater supporting instream beneficial uses in the Santa Clara River (or estuary), or other GDE. As noted previously, SGMA legislation and SGMA regulations, contains an expanded definition of sustainability that includes avoiding undesirable results, includes changes to

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groundwater dependent ecosystems that have significant and unreasonable adverse impacts on all recognized beneficial uses of groundwater and related surface waters (Water Section 10720). Pages 2-63 through 2-64, 3rd paragraph We would note that reductions in upper aquifer system pumping would not only inhibit seawater intrusion, but also benefit instream beneficial uses in the Santa Clara River (and estuary), as well as other GDE. 2.4.4 Uncertainties in the Water Budget Page 2-65, 1st paragraph. The water budget should include more than just the groundwater inputs (whether via natural recharge or artificial recharge) and the groundwater extractions for out-of-stream consumptive beneficial uses. For instance, the budget should also and explicitly incorporate groundwater which serves to support instream beneficial uses, including GDE. One of the principal uncertainties is the relationship among the groundwater levels (particularly in the semi-perched aquifers), the water diversions for recharge (and the groundwater extraction activities), and the surface flows in the lower Santa Clara River (and estuary). This should be added as a separate enumerated uncertainty. Page 2-66 Point 8. The Draft Plan notes that “shallow groundwater in the Oxnard Subbasin is potentially captured by tile drains, rather than recharging the groundwater.” The Draft Plan also notes that groundwater levels in the semi-perched aquifer within the Oxnard Subbasin could be discharged (i.e., lowered) by tile drains if the groundwater levels increase in the groundwater model. This groundwater-management activity has the potential to adversely impact instream beneficial uses, including fish migration, spawning and rearing, as well as other GDE. In addition to determining the amount of flow discharged from the tile drains, the effects of these facilities on groundwater levels, particularly semi-perched aquifers, and in turn its effects on surface flows in the mainstem of the Santa Clara River, as well as other GDE, should be determined and disclosed. Point 10. The dedicated monitoring wells to be installed should include wells in the semi-perched aquifers which are currently not monitored; these wells should be placed at depths that monitor the exchange of groundwater and surface water. Additionally, all production wells should be metered. 2.4.5 Projected Water Budget Page 2-66. The Draft Plan indicates FCGMA management actions will be incorporated into the first 2-year water budget projection “to increase the sustainable yield of the Oxnard Subbasin.” This approach does not address all the important policy objectives of SGMA; the SGMA legislation and regulations specifically provide for avoiding undesirable results, including changes to groundwater dependent ecosystems that have significant and unreasonable adverse impacts on all recognized beneficial uses of groundwater and related surface waters (Water

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Section 10720). This standard cannot be met by simply establishing minimum groundwater levels to increase the sustainable yield of the Oxnard Subbasin, without also determining the relationship between those levels and surface water flows in the Santa Clara River (and estuary), as well as other GDE, as a prerequisite. 3.1 Introduction to Sustainable Management Criteria Page 3-1, 1st paragraph The Draft Plan indicates that “seawater intrusion is the primary result that occurs when groundwater production exceeds sustainable yield.” While seawater intrusion is a significant adverse effect of groundwater extraction, this formulation does not recognize the interrelated connection between groundwater extraction and surface diversions/groundwater recharge operations conducted by the UWCD at the Vern Freeman Diversion on the lower mainstem of the Santa Clara River. Groundwater-management activities include substantial diversion of surface waters at the Vern Freeman Diversion and subsequent retention of these waters for percolation into the groundwater at the UWCD’s El Rio Recharge Basin. These past and ongoing operations of this diversion impact endangered adult and juvenile steelhead; future operations of this diversion are anticipated to affect this species as well. The relationship of groundwater management activities (including both recharge and groundwater extraction activities) and the effects of the related Vern Freeman Diversion on surface flows below the diversion and the maintenance of surface flows supported by groundwater should be explicitly addressed in the revised Plan. See comments above on this topic. Page 3-1, 2nd and 3rd paragraphs The planning goals identified by the FCGMA Board of Directors for the Oxnard Subbasin do not, but should, explicitly include environmental protection goals as required by SGMA. Instead, the goals are aimed primarily at protection of sustainable water supplies for out-of-stream consumptive uses, particularly crop production. It is not appropriate to assume that non-consumptive instream uses (and other GDE) would be incidentally protected by meeting the planning goals identified by the FCGMA. It is clear that efforts to sustain this subbasin, for example, through the continued operation of the Vern Freeman Diversion Dam, pose effects that threaten the long-term survival and recovery of endangered steelhead in the Santa Clara River Watershed. As a result, the planning goals should include ecologically meaningful environmental protections, consistent with the requirements of SGMA, to avoid abetting the existing harmful environmental effects, which are well documented for the Vern Freeman Diversion Dam. Page 3-1, 4th paragraph The Draft Plan indicates that “Groundwater elevations are the primary metrics by which progress toward meeting the planning goals of the Oxnard Subbasin will be measured.” The further discussion of management criteria also suggests “Sustainable management of the Oxnard Subbasin does not necessarily mean, however, that springtime high groundwater level in the basin remain the same year after year.” And that seasonal fluctuation of groundwater elevations

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may be acceptable if “the drawdown[s] are not significant or unreasonable.” This characterization of the Draft Plans goals is aimed primarily a maintaining a water supply for out-of-stream beneficial uses, and is not fully consistent with the requirements of SGMA, which include the sustainable protection of all recognized beneficial uses of groundwater and related surface waters (Water Section 10720). This standard cannot be met by simply establishing minimum groundwater levels, without also determining the relationship between those levels and surface water flows in the Santa Clara River (and estuary), as well as other GDE. Instream beneficial uses in the Santa Clara River (and estuary) as well as other GDE may not have the same tolerances as other out-of-stream consumptive beneficial uses. Differences in habitat metrics must also be considered to protect essential habitat features (e.g., adequate timing, duration, and duration of surface flows to support migration, spawning, or rearing of steelhead). The groundwater storage and groundwater levels controls aquifer and surface flow interactions and this relationship should be explicitly addressed in the revised Plan. 3.2 Sustainability Goal Page 3-2, 1st paragraph The Draft Plan indicates that “The primary sustainability goal in the Oxnard Subbasin is to increase groundwater elevations inland of the Pacific coast, in all aquifers, to elevations that were selected, by aquifer, based on the height of the column of seawater above discharge points of the aquifers offshore in the Mugu and Hueneme Canyons and accounted for the greater density of seawater relative to freshwater.” This goal is of concern for two primary reasons. First, this is really a measurable objective, because maintenance of an identified groundwater level is not a goal in itself, but a means to achieve a goal (or goals), keeping in mind that a “goal” refers to a desired outcome, not the means or approach to attain an outcome. Second, the goals of the revised Draft Plan should be those which are identified in SGMA, accompanied by specific measurable objectives (measurable groundwater elevations, groundwater production level, groundwater quality standards, extent of seawater intrusion, quantified surface flow patterns, etc.) to attain the goal(s). The goal of the Draft Plan appears support the objective of a positive gradient toward the sea to prevent further seawater intrusion, but this does not address the issue of preserving base flows for recognized, non-consumptive beneficial uses of surface flows, including but not limited to the endangered Southern California Steelhead DPS. 3.3 Undesirable Results Page 3-2, 1st paragraph, last bulleted point The phrase “Depletions of interconnected surface water” should be modified to include the phrase “that adversely affect natural surface waters and GDE.” These include annual seasonal fish migration, spawning, or rearing of the endangered Southern California Steelhead DPS, as well as the other native anadromous fishes of the Santa Clara River.

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Page 3-3, 1st and 2nd paragraphs In addition to lowered groundwater levels “which could not recover during a multi-year period of above average precipitation”, adverse results could result from seasonal or annual lowering of groundwater levels can affect instream beneficial uses as well as GDE. See comment above on this topic. Page 3-3, 3rd paragraph The Draft Plan notes that one factor contributing to the recovery of water levels following drought periods was “the amount of surface water that was diverted from the Santa Clara River and infiltrated through spreading basins to recharge the aquifers.” As noted above, the Southern California Steelhead Recovery Plan identified the following critical recovery action for the Santa Clara River, which provides in part:

Implement operating criteria to ensure the pattern and magnitude of water releases, including bypass flows from diversions from Vern Freeman Diversion, Santa Felicia, Pyramid, and Castaic dams provide the essential habitat functions to support the life history and habitat requirements of adult and juvenile steelhead. (Table 9-2, p. 9-17)

Page 3-3, 5th paragraph Regarding the use of “minimum threshold groundwater elevations to determine . . . unreasonable chronic lowering of groundwater”, see the above comments on hydrologic and habitat metrics. 3.3.2. Reduction in Groundwater Storage Page 3-4, 2nd paragraph The Draft Plan notes that “Groundwater production in the Subbasin may result in significant and unreasonable reduction in groundwater storage if the volume of water produced from the basin exceeds the volume of fresh water recharging the Subbasin over a cycle of drought and recovery.” As noted earlier in these comments, groundwater depletions also have the potential to impact instream beneficial uses, as well as other GDE, and do so on a shorter, seasonal or interannual time-frame. While it may be acceptable to sustain a temporarily depleted groundwater basin through a drought, because there are other means for adjusting either the supply or the demand of water for out-of-stream consumptive beneficial uses, such is not the case with many aquatic organisms such as the endangered steelhead that depends on the natural availability of groundwater to sustain critical surface-water connectivity and, therefore, completion of key life-history pathways, including the species life cycle. Page 3-4, 3rd paragraph The Draft Plan refers to the pumping records from 1985 to 2015. The historical volumes of groundwater pumping during the 31 year period while providing an important pumping record

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are limited in two important ways. First, the record extends only from the most recent period of pumping, and does not capture the longer-term record of pumping in the Oxnard Subbasin and thus provide meaningful historical perspective which can be used to assess historic groundwater levels. This limitation should be explicitly recognized in the revised Plan. Second, the record captures only a part of the actual pumping activities within the Oxnard Subbasin, because not all groundwater wells are metered. It would be important to note this limitation in the revised draft Plan, and if possible to provide some estimate of the number and volume of pumpage from the unmetered groundwater wells. Page 3-4, 4th paragraph; Page 3-7, 1st paragraph See comments above regarding the use of minimum thresholds metric measures expressed in groundwater levels to prevent lateral seawater intrusion to achieve all the policy objectives of SGMA. 3.3.3 Seawater Intrusion Page 3-7, 1st paragraph See comments above regarding other adverse results of seawater intrusion. Page 3-7, 2nd paragraph The limitation of seawater intrusion is more properly characterized as a measurable objective, than a goal in and of itself. 3.4.4 Degraded Water Quality 3.3.4.1 Chloride and TDS Page 3-9, 1st full paragraph The Nature Conservancy noted that “The Semi-perched aquifer is recharged by local precipitation and agricultural return flows. The return flows and seawater intrusion result in marginal water quality (high TDS and chloride) as a result, little to no pumping in the semi-perched aquifer” (TNC 2017, p. 12). In addition to limiting the volume of groundwater available to out-of-stream consumptive beneficial uses (e.g., agriculture, municipal, industrial and domestic uses), increased concentrations of TDS has the potential to impact other non-consumptive beneficial uses (e.g., GDE). This summary in the revised Plan should include these impacts to beneficial uses as a separate 3rd category, which involves “limiting the suitability of groundwater, particularly semi-perched aquifers to support salt intolerant or sensitive species of aquatic plants in GDEs.”

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Page 3-9, 3rd full paragraph The Draft Plan does not propose identifying a specific minimum threshold for chloride concentrations “because the groundwater water elevation minimum thresholds proposed to address seawater intrusion will prevent the migration of brackish water and brines into to previously un-impacted areas.” This proposal is not appropriate for at least two reasons: 1) there are other sources of chlorides in the Oxnard Subbasin besides from saltwater intrusion; agricultural runoff can contain high concentration of chlorides which infiltrate into the groundwater, particularly the shallow semi-perched aquifers, which can result in elevated levels of chloride (Avent-Environ 2007); and, 2) the use of groundwater elevations as a substitute minimum threshold for chlorides, only addresses the deeper groundwater basins within the Oxnard Subbasin, and does not include the shallow semi-perched aquifers which are most closely associated with GDE. As a result, the revised Draft Plan should contain specific minimum thresholds for chloride to ensure protection of all the recognized beneficial uses of the groundwater of the Oxnard Subbasin, including out-of-stream, non-consumptive beneficial uses associated with natural surface water courses and other GDE. It is not clear, but should be, whether the Draft Plan addresses the discharge of chemical by agricultural operations which subject to the Total Maximum Daily Loads (TMDLs) standards established by the Los Angeles Regional Water Quality Control Board for the Santa Clara River Watershed. 3.3.4.2 Nitrate The Draft Plan concludes that concentrations of nitrates have not resulted in significant and unreasonable impacts to beneficial uses and user of the Oxnard Subbasin “because municipal users of ground water in this area have the ability to blend groundwater with nitrates exceeding the MCL [Maximum Concentration Level] with other water, and nitrate does not impact the beneficial use of groundwater for agriculture.” This assessment does not directly address the shallow semi-perched aquifers which support out-of-stream, non-consumptive beneficial uses associated with surface water courses or other GDE. These shallow-semi-perched aquifers are subject to agricultural run-off with contains nitrates. These nitrates are known to cause nuisance plant growth in surface water courses, and potentially in other GDE. Elevated nitrate concentrations may promote excessive growth of algae during low flow or static conditions which may lead to eutrophication (Smith et al. 1999). The effects of eutrophication include the removal of dissolved oxygen from a water body due to dying and decaying algae and other plant growth. Eutrophication has been recognized as the most widespread water quality issue in the United States (Carpenter et al. 1998). Reductions in dissolved oxygen may affect all life stages of steelhead as well as other aquatic organisms including macroinvertebrates that serve as juvenile steelhead prey. High levels of nitrates can also substantially degrade water quality (Bennett et al. 2001). The Draft Plan notes that “. . . nitrate concentrations above WQOs [Water Quality Objectives] and BMOs [Basin Management Objectives] are likely a legacy of historical sceptic and historical

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agricultural fertilizer application practices.” While the installation of sewer lines into this area may have addressed the domestic sources of nitrates, the use of fertilizers for agricultural practices continues. The Draft Plan does not, but should, provide an assessment or propose a method to assess the level and significance of these agricultural derived nitrates. See additional comments above regarding TMDLs and below. Page 3-10, 1st full paragraph. The Draft Plan asserts that “. . . the reduction in nitrate concentration results from dilution of groundwater by lower nitrate concentrations of surface water recharge form the Freeman Diversion. If environmental permits constrain diversions from the Santa Clara River in the future the degree of nitrate dilution will be decreased. Reducing pumping will likely not decrease nitrate concentrations.” This characterization does not distinguish between the shallow, semi-perched aquifers which are directly influenced by surface flows, and the deeper aquifers in the Oxnard Subbasin which are recharged by both natural stream flow and forced percolation through the operation of the Vern Freeman Diversion and the El Rio spreading basins. Also, it appears to address the problem of unnaturally elevated concentrations of nitrate through simple dilution, rather than addressing the complex sources. The concentration of nitrates in upper semi-perched aquifers are largely influenced by the inputs of nitrates form domestic, municipal, and agricultural sources, and the surface flows of the Santa Clara River. The concentration of nitrates is primarily lowered as a result of the interconnected surface flows in the Santa Clara River, less so by recharge from the Freeman Diversion and percolation operation. The diversion of surface flows from the Santa Clara River for the recharge of the lower, deeper aquifer in the Oxnard Subbasin serves to reduce nitrate concentration in these aquifers, but reduces the amount of water available for the dilution of groundwater in the semi-perched aquifers. The nitrate concentration of the lower deeper aquifers in the Oxnard Subbasin is largely the result of the extraction of groundwater from these aquifers to support agriculture, resulting in seawater intrusion into the Oxnard Subbasin. In view of the requirements of SGMA to protect all recognized beneficial uses depending upon or influenced by groundwater resources, it is inappropriate to characterize constraints on diversions from the Santa Clara River to protect instream beneficial uses as an inherently in conflict with protection of out-of-stream, consumptive beneficial uses of the groundwater of the Oxnard Subbasin, particularly those shallow, semi-perched aquifers which have direct interconnections with surface flows. Further, the statement that “Reducing pumping will likely not decrease nitrate concentrations” is speculative, at best, with no supporting data presented, and does not recognize the natural recharge potential of the Oxnard Subbasin. Chemical monitoring should be added to the monitoring program of either FCGMA or UWCD. Page 3-10, 2nd full paragraph Regarding the statement that “nitrate is not considered to be a sustainability indicator, see the comments above regarding the role of nitrates in plant growth.

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3.3.5. Land Subsidence Page 3-10, 1st paragraph The Draft Plan states “Groundwater production is only one cause of subsidence of the Oxnard Basin,” and refers to tectonic forces and oil and gas production. However, there is no evidence presented that tectonic forces or oil production (the latter of which is not generally located on synclinal formations that characterize the Oxnard Subbasin) play a major role in the land subsidence that has been recorded in part of the Oxnard Plain. Given the range of displacement reported in the area, tectonic uplift and subduction are likely negligible. However, if this is believed to be of significant question, monitoring stations that could be used to separate the effects of groundwater withdrawal from other causes of subsidence should be identified and a plan developed for monitor such effects. Page 3-10, 2nd paragraph The Draft Plan indicates, that “Land subsidence has not substantially interfered with surface land uses in the Subbasin.” We would note that there has been a substantial degradation of stream channel elevations in the lower river as a result of the legacy effects on in-channel mining. This drop in elevation in the vicinity of the Vern Freeman Diversion has resulted in a drop of about 15 ft in the river bed elevation immediately below the Diversion since its construction in 1993. The extent to which this change in elevation has been exacerbated by ground subsidence due to groundwater extraction from the lower, deeper groundwater basins in the Oxnard Subbasin has not been addressed, but should be as part of the revised Draft Plan. Page 3-10 through 3-11, 3rd paragraph The minimum threshold metric against which subsidence will be measured is the water levels that were selected to prevent lateral seawater intrusion. As with chloride and nitrate metrics, the minimum threshold should be adequate to protect other recognized beneficial uses of groundwater, including non-consumptive uses such as GDE, and not be limited to the protection of groundwater extraction for consumptive beneficial uses. 3.3.6 Depletions of Interconnected Surface Water Page 3-11, 1st paragraph The Draft Report states that the “Sustainable groundwater management of the Oxnard Subbasin will mitigate or minimize the undesirable results from depletion of interconnected surface water.” However, the Draft Plan in its present form does not adequately address the depletion of interconnected surface water for the reasons presented in comments above, and additional comments provide below. Most fundamentally, the Draft Plan does not, but should, adequately recognize the integral and interdependent nature of the relationship between the surface water diversions made at UWCD’s Vern Freeman Diversion (and the related groundwater recharge operations at the El Rio

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spreading basins) and the groundwater extraction activities in the Oxnard Subbasin. The current diversion operations at the Vern Freeman Diversion have a number of adverse impacts on endangered steelhead; these include, but are not limited to, modification of the magnitude and pattern of river discharge downstream of the diversion dam, with concomitant effects on steelhead passage through the lower river system. Because groundwater-management activities entail United’s diversion operations at the Vern Freeman Diversion, and the related impacts on endangered adult and juvenile steelhead, these activities should be explicitly addressed in the revised Draft Plan. (For a fuller description of the effects of the Vern Freeman Diversion on the steelhead resources of the Santa Clara River see NMFS’ 2008 biological opinion for the Vern Freeman Diversion (NMFS 2008). Because the FCGMA’s Plan sets forth a number of conditions or activities by which groundwater management would be undertaken in the Santa Clara River Watershed, and these activities as currently proposed may translate into negative impacts on endangered steelhead, the revised Plan should propose measures to avoid or fully mitigate the impacts on listed species. Page 3-11, 2nd paragraph The Draft Plan notes that depletion of interconnected surface water as a result of groundwater extractions “may result in significant and unreasonable depletion of interconnected surface water if the groundwater level were lowered to an elevation below which the vegetation in the existing CDE could no access groundwater over the length of time that negatively affected the health of the GDSE.” The adverse effects of lowered groundwater in the semi-perched aquifers is not limited to effects on vegetation. Such depletions can also result in effects on surface flows, including the timing, duration, and rate of flows, which can adversely affect both adult and juvenile steelhead which depend on such flows to complete phases of the freshwater life-cycle, including migration, spawning and rearing. Modification of surface-flow patterns can affect both the amount and the quality of aquatic habitat available to steelhead, as well as other aquatic organisms (e.g., aquatic invertebrates) which provide a food sources of rearing juveniles. In addition, the reduced or eliminated surface flows can translate into decreased or absent riparian vegetation, which provides water-temperature regulation, and a source of refugia habitat and food to waterways. Page 3-11, 3rd paragraph The Draft Plan notes that “The Semi-Perched Aquifer has high concentrations of TDS and chloride from agricultural return flows, saline connate water, and coastal flooding.” The Draft Plan does not assess the effects of these degraded water conditions on the instream, non-consumptive beneficial uses of the interconnected surfaces waters of the Oxnard Subbasin, or identify minimum threshold standards. However, the Draft Plan notes that the “ . . . water quality in this aquifer is not favorable to an agricultural or municipal use.” This assessment suggests that the water quality conditions in this aquifer may not also be suitable to support native vegetation. See comments above regarding TDS and chloride, and nitrates from agricultural effluents.

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Page 3-11, 4th paragraph The Draft Plan identifies six potential GDE, including the lower Santa Clara River, and notes that “Groundwater elevations in the Semi-Perched aquifer have remained relatively stable since 1990, in large part because they are regulated by the tile drain system that alleviates high groundwater elevations.” As noted above, the Draft Plan indicates that the average annual loss of shallow groundwater due to tile drains is 17,045 AFY. This groundwater is discharged to local drainage ditches and then to surface water bodies such as Revlon Slough and Calleguas Creek. High groundwater elevations historically help support natural surface water (expressed as artesian springs) on the Oxnard Plan and other GDE (Beller et al 2011). This groundwater-management activity has the potential to adversely impact instream beneficial uses, including fish migration, spawning and rearing, as well as other GDE. The potential effects on base and low flows in the Santa Clara River and other surface waters should be evaluated and groundwater-management strategies developed to eliminate, reduce, or otherwise mitigate this management of shallow groundwater conditions. This assessment should not be predicated on future projects to utilize water from the semi-perched aquifer, as suggested in the Draft Plan, but be included in the revised Draft Plan. 3.4 Minimum Thresholds The Draft Plan proposes to set forth minimum thresholds for each of the six sustainability indicators (chronic lowering of groundwater levels, reduction of groundwater storage, seawater intrusion, degraded water quality, land subsidence, and depletion of interconnected surface water). All of these minimum standards are expressed in terms of minimum groundwater elevations , and are based on historical record of groundwater elevations in individual aquifers, and are intended to primarily mitigate the effects of seawater intrusion that affects principally out-of-stream, consumptive beneficial uses of groundwater. This approach assumes that addressing the seawater intrusion issue through the maintenance of minimum groundwater elevations, will also adequately address the other beneficial uses of the groundwater’s of the Oxnard Subbasin, including the beneficial interconnected surface waters of the Santa Clara River and other GDE. The approach does not provide an appropriate framework for achieving the full range of policy objectives of SGMA. First, we would note that using historical groundwater well record (which is both relatively recent and limited in its geographic scope) has the functional effect of relying on degraded groundwater conditions as the standard for future management (including the condition of seawater intrusion into the lower groundwater basins). These depressed historic groundwater levels have, in many cases, resulted in adverse impacts to both instream and out-of-stream beneficial uses of the groundwater of the Oxnard Plain, including, but not limited to the loss or degradation of groundwater storage in the lower groundwater basins, and the seasonal depletion of groundwater levels in semi-perched aquifers that support GDE. Second, minimum groundwater level thresholds themselves, will not provide a meaningful metric for supporting and protecting all the beneficial uses of the groundwater of the Oxnard Subbasin. In particular, the relationship between groundwater elevations, particularly in semi-perched aquifers which support interconnected surface waters, must be identified, along with the flows necessary to

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minimize impacts from the lowering of groundwater levels. The Draft Plan does not include any groundwater/flow/habitat analysis, but merely assumes that the maintenance of existing historic groundwater levels is adequate to prevent any unreasonable adverse impacts to all the beneficial uses of the groundwater of the Oxnard Subbasin. See comments above. Page 3-13, 2nd and 3rd full paragraphs The Draft Plan indicates that UWCDS model scenario (F) was selected to determine the minimum thresholds for the purpose of identifying sustainable yield of the Oxnard Subbasin. As noted above, this model scenario does not provide an appropriate standard for achieving the full range of policy objectives of SGMA, which include more than just assuring sustainable management of groundwater supplies for consumptive beneficial uses such as municipal, domestic, and agricultural supply. The revised Plan should be based on a reliable representative model which is subjected to field monitoring and testing.. Page 3-14, 1st full paragraph The Draft Plan states that “Scenario F results indicate that the simulated groundwater elevations in the Fox Canyon Aquifer will limit the impacts to seawater intrusions and are also protective of adjacent groundwater basins.” This is another example of an inappropriate use of a single metric to address the full range of beneficial uses of the Oxnard Subbasin, which should be replaced with a metric in the revised Plan which is adequate to protect all the beneficial uses of the Oxnard Subbasin in a sustainable way consistent with the requirements of SGMA. Page 3-14, 3rd full paragraph The Draft Plan indicates that “the minimum thresholds for several inland wells were set to match the previous historical low groundwater elevation. As noted above, this is not an appropriate standard because it merely maintains the status quo, rather than rectifies any adverse impacts from past groundwater extraction practices, and does not provide adequate guidance for future groundwater-management activities. 3.4.1 Chronic Lowering of Groundwater Levels Page 3-14, 2nd paragraph The Draft Plan indicates that some minimum thresholds may impact groundwater users in the Subbasin by requiring both an overall reduction in groundwater production relative to historic levels, and potentially by requiring a redistribution of groundwater pumping in with the Subbasin.” The revised Plan should also disclose that reducing pumping in some semi-perched aquifers with interconnected surface waters could restore ecological functions in GDE.

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3.4.2 Reduction of Groundwater Storage Page 3-15, 1st paragraph The Draft Plan indicates that selected minimum thresholds in groundwater storage “are anticipated to improve the beneficial uses of the Subbasin.” It is not clear which beneficial uses are being referred to here; they should be specifically identified in the revised Plan. 3.4.3 Seawater Intrusion Page 3-15, 1st and 2nd paragraph The Draft Plan indicates that the overall amount of freshwater storage will be increase as a result of the minimum standards for seawater intrusion. However, the revised Plan should make clear how this increased storage will affect the existing or potential Vern Freeman Diversion and related El Rio spreading grounds operation, or how the groundwater recharge program will affect seawater intrusion given that the recharged groundwater is later pumped for agricultural irrigation or other out-of-stream consumptive beneficial uses. 3.4.4 Degraded Water Quality Pages 3-15, 1st through 4th paragraphs See comments above regarding TDS, Chloride and Nitrates, and the comments below regarding “Water Level Measurements: Spatial Data Gaps by Aquifer”. 3.4.6 Depletions of Interconnected Surface Water Page 3-17, 1st and 2nd paragraphs The Draft Plan proposes to address depletions of interconnected surface waters and related GDE by establishing minimum thresholds expressed in terms of groundwater elevations. The proposed minimum thresholds would be “equal to or high that the lowest groundwater elevations” measured at wells identified in Table 3-1. These thresholds should be based on properly functioning ecosystems. Otherwise the Draft Plan would only support the ecosystem of the Oxnard Subbasin (and dependent upstream areas as well) at a severely depressed, and perhaps unsustainable level. Restoring impacted recognized instream, non-consumptive beneficial uses, including the endangered Southern California Steelhead DPS should be an integral component of the revised Draft Plan. As noted above, this foregoing approach is inappropriate for at least a few reasons. First, the historic well records are limited (both temporally and spatially), and do not by themselves provide an adequate or appropriate base-line for future management of the Oxnard Subbasin under SGMA. These historically depressed historic groundwater levels have, in many cases, resulted in adverse impacts to both instream and out-of-stream beneficial uses of the groundwater of the Oxnard Plan, including, but not limited to the loss or degradation of

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groundwater storage in the lower groundwater basins, and the seasonal depletion of groundwater levels in semi-perched aquifers that support GDE. Second, the well elevation standards, without linking them to instream flow standards, are not sufficient for dealing with depletions of interconnected surface waters (Barlow and Leake 2101). In particular, the relationship between groundwater elevations, particularly in semi-perched aquifers which support interconnected surface waters, must be identified, along with the flows necessary to minimize impacts from the lowering of groundwater levels. The Draft Plan does not include any groundwater/flow/habitat analysis, but merely assumes that the maintenance of existing historic groundwater levels is adequate to prevent any unreasonable adverse impacts to all the beneficial uses of the groundwater of the Oxnard Subbasin. 3.5 Measurable Objectives Page 3-18, 1st paragraph The Draft Plan notes that a “measurable objective” is a quantifiable goal to the maintenance or improvement of specified groundwater conditions to achieve the sustainability goal of the adopted Groundwater Sustainability Plan. The planning goals identified by the FCGMA Board of Directors for the Oxnard Subbasin do not explicitly include environmental protection goals as consistent with SGMA, but are aimed primarily at the protection of sustainable water supplies for out-of-stream consumptive uses. It is not appropriate to assume that non-consumptive instream uses (and other GDE) would be incidentally and adequately protected by meeting the planning goals identified by the FCGMA. This issue should be corrected in the revised Plan. 3.5.1. Chronic Lowering of Groundwater Levels. See comments above. 3.5.2 Reduction of Groundwater in Storage See comments above. 3.5.3 Seawater Intrusion 3.5.4 Degraded Water Quality See comments above. 3.5.6 Depletions of Interconnected Surface Water See comments above. 4. Monitoring Networks Table 4-6: Characterization of Spatial Data Gaps by Aquifer

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Screened Aquifer (Semi-Perched). The Draft Plan acknowledges that there is limited spatial coverage of wells in this aquifer, but indicates that because this is not a “managed aquifer” the only additional wells required in this aquifer would be in the vicinity of Revolon Slough and Calleguas Creek potential DGEs. The proposal should be expanded to include the perched aquifer associated with the upper northwest portion of the lower Santa Clara River, between Central Avenue and Highway 118. Table4-7: Screened Aquifers at Proposed New Monitoring Well Locations Proposed New Well Location ID. The proposed new monitoring well locations should be expanded to include the perched aquifer associated with the upper northwest portion of the lower Santa Clara River, between Central Avenue and Highway 118; these wells should be placed at depth that monitor the exchange of groundwater and surface water. See Figure 4-17. 4.3.4 Shallow Groundwater Monitoring Near Surface Water Bodies and GDEs Page 4-10, 1st paragraph The Draft Plan notes that currently “there are relatively few wells that can be used to monitor the shallow groundwater which may be interconnected with surface water bodies . . .” In order to achieve the groundwater-management requirements of SGMA, groundwater aquifers which are interconnected surface water bodies supporting recognized beneficial uses, including instream, non-consumptive beneficial uses such as fish migration, spawning, and rearing, must be adequately monitored in order to assess the effects to extracting water from these basins, and to identify minimum thresholds for individual indicators. The proposal to add 14 new well locations is critical to this effort. Towards this end, the proposed new monitoring well locations should be expanded to include the perched aquifer associated with the upper northwest portion of the lower Santa Clara River, between Central Avenue and Highway 118; these wells should be placed at depth that monitor the exchange of ground and surface water. See Figure 4-17. Proposed Improvements Pages 4-10 through 4-11, 1st and 2nd paragraphs. See comments above regarding the additional of an additional well location. 4.3.5 Surface Water: Stream Gauges and Measurements of Interconnected Surface and Groundwater The Draft Plan recognizes that the use of exiting stream network is not adequate to precisely quantify surface flows in surface water channels, and therefore their contribution to deep percolation into the Oxnard Subbasin. The Draft Plan therefore recommends the development of calibration of a surface water model for all major unlined channel in the Oxnard Subbasin, including the Santa Clara River. However, the Draft Plan does not, but should, provide any detail about how this model will be developed, or its capabilities. The model should be designed to capture the full range of the hydrograph, including based flow characteristics (timing,

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duration, magnitude, rate of change) that are relevant to aquatic organisms, including the endangered Southern California Steelhead DPS. This should be described in further detail in the revised Draft Plan (See Mercer and Faust 1980). 4.3.6 Surface Water: Flows in Agricultural Drains in the Oxnard Plain Page 4-12, 1st paragraph The Draft Plan notes that “Discharge flow are currently unmeasured in the drainage system, frequently referred to as the ‘tile drains’, that was installed throughout the Oxnard Plain in the 1950s”. However, the Draft Plan notes that the average annual loss of shallow groundwater due to tile drains is 17,045 AFY. This groundwater is discharged to local drainage ditches and then to surface water bodies such as Revlon Slough and Calleguas Creek. It is unclear how and to what extent these tile drains effect other surface water bodies such as the Santa Clara River (and estuary) and other GDE. However, removal of this water from semi-perched aquifers that support surface water or surface flows has the potential to adversely affect beneficial uses, particularly non-consumptive beneficial uses associated with the GDE, including the Santa Clara River (and estuary). The potential effects on base and low flows in the Santa Clara River should be evaluated and groundwater-management strategies developed to eliminate, reduce, or otherwise mitigate this management of shallow groundwater conditions. The feasibility study to identify the best locations in the drainage system for installing flowmeters should be outlined in the revised Draft Plan. 4.4.2 Schedule Requirement for Monitoring Groundwater Quality Page 4-14, 1st paragraph The Draft Plan notes that “nitrate concentration in the Forebay is not a sustainability indicator. See comments above regarding nitrates. 5.1 Introduction to Projects and Management Actions Page 5-1 1st paragraph Regarding the goal of long-term sustainability for the Oxnard Subbasin see the comment about the requirements of SGMA. Page 5-1, 2nd paragraph The Draft Plan asserts that seawater intrusion “will have the greatest impact on beneficial uses of groundwater in the Subbasin.” This characterization does not adequately recognize the other instream, non-consumptive beneficial uses of the groundwater of the Oxnard Subbasin, including those associated with interconnected surface waters such as the Santa Clara River, as well as other DGEs. Further, this characterization does not recognize the adverse effects of the surface diversion at the Vern Freeman Diversion, and the related El Rio spreading grounds operation, on the Santa Clara River and estuary, including but not limited to the migration, spawning and

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rearing of the federally listed endangered Southern California Steelhead DPS. See comment above. Page 5-1, 3rd paragraph The Draft Plan refers to “potential ways to enhance the future sustainable yield of the Oxnard Subbasin; however, SGMA requires identifying numeric minimum thresholds to prevent significant and unreasonable adverse impacts on all recognized beneficial uses of ground and surface water, not simply maximizing the sustainable extraction of groundwater resources for out-of-stream consumptive beneficial uses. Pages 5-2 through 15 The Draft Plan identifies a series of projects which are to be incorporated into the future water budget projections. Specific comments are provided below on specific projects, identified by project name. However, we would make two general observations. First, virtually all of the identified project as aimed at increasing supply, not limiting demand (through water conservation practices). Second, the integral and inseparable role of the current Vern Freeman Diversion and related El Rio spreading grounds operation is assumed to be a fixed component in the water budget. See NMFS comment letter to the UWCD regarding their draft Multi Species Habitat Conservation Plan for the Santa Clara River system for a discussion of the relationship between UWCD diversions at the Vern Freeman Diversion and UWCD groundwater recharge program (NMFS 2017). Page 5-3 Project: South Oxnard Brackish Water Treatment Comment: The reclamation of 20,000 acre feet per year of brackish water has the potential for reducing the need for surface diversions as well as groundwater recharge, depending on how the reclaimed water is used. Page 5-4 Project: State Water Intertie Pipeline Comment: The importation of 20,000 acre feet per year of brackish water has the potential for reducing the need for reducing surface diversions as well as groundwater extractions. Page 5-5 Project: Groundwater Recovery Enhancement and Treatment Program Comment: The reclamation of up to 28,000 acre feet per year of wastewater has the potential for reducing the need for surface diversions as well as groundwater extractions.

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Page 5-6 Project: Santa Clara River Conveyance of State Project Water Comment: This proposal to convey 20,000 acre feet of water per year from Castaic Lake into the Santa Clara River raises a number of significant environmental issues; these include, but are not limited to: 1) conveying exotic species known to be within the State Water Project system; 2) imprinting juvenile steelhead with waters not native to the Santa Clara River watershed; 3) disrupting migration quest for steelhead and other native fishes within the Santa Clara River watershed; and 4) affecting spawning and rearing conditions within the mainstem of the Santa Clara River systems. Without having more information about this proposal, particularly the timing, duration, and rate of flows (and rates of flow) changes, it is not possible to provide more detailed comments on the potential effects of this proposal. Page 5-7 Project: Anacapa Project/NW Oxnard Well Field Comment: This proposal to intercept an estimated 3,000 to 5,000 acre feet per year of groundwater underflow in the Oxnard Basin that would otherwise flow to the ocean, has the potential to affect aquatic resources in Santa Clara River estuary, as well as other GDE. This project appears to be predicated on the inappropriate notion that groundwater discharged to the sea is not a beneficial use of water. Page 5-8 Project: Diversion and Spreading Basins (El Rio, Noble, Saticoy, and Pits (Ferro and Rose) Comment: NMFS’ Southern California Steelhead Recovery Plan identifies the following critical

recovery action for the Santa Clara River, which provides, in part:

Implement operating criteria to ensure the pattern and magnitude of water releases, including bypass flows from diversions from Vern Freeman Diversion, Santa Felicia, Pyramid, and Castaic dams provide the essential habitat functions to support the life history and habitat requirements of adult and juvenile steelhead. (Table 9-2, p. 9-17)

The revised Draft Plan should include as part of its water budget analysis the operations of the Vern Freeman Diversion. Groundwater-management activities include substantial diversion of surface waters at the Vern Freeman Diversion and subsequent retention of these waters for percolation into the groundwater at the UWCD’s El Rio Recharge Basin. Maintenance of groundwater levels and prevention of groundwater quality degradation have the potential to impact endangered adult and juvenile steelhead. The relationship of groundwater management activities (including both recharge and groundwater extraction activities) and the effects of the related Vern Freeman Diversion on surface flows below the diversion and the maintenance of surface flows supported by groundwater should be explicitly addressed in the revised Draft Plan.

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Page 5-9 Project: Oxnard Hueneme (OH) Pipeline Comment: Water extracted from the Forebay area of the Oxnard Subbasin has the potential to affect pumping patterns in other portions of the Subbasin, including those semi-perched aquifers which support interconnected surface waters, and thus potentially affecting DGEs. Page 5-1 Project: Pumping Trough Pipeline (PTP) Comment: This project involves delivering a blend of surface water diverted from the Santa Clara River at the Vern Freeman Diversion directly to agricultural operations in the central portion of the Oxnard Subbasin in lieu of pumping. See comments above regarding the operations of the Vern Freeman Diversion and El Rio spreading ground operations. Page 5-11 Project: Pleasant Valley Pipeline Comment: This project delivers between 0 and 11,200 acre feet of surface water diverted from the Santa Clara River at the Vern Freeman Diversion directly to the Pleasant Valley County Water District for use by growers operating in the south and western portion of Pleasant Valley and southeastern Oxnard Subbasin in lieu of pumping. See comments above regarding the operations of the Vern Freeman Diversion and El Rio spreading ground operations. Page 5-12 Project: Conejo Creek Diversion No comment. Page 5-13 Project: Imported Water – South of Delta Limited Term Supplies Comment: It is unclear how this would or could be used to reduce pumping from the Oxnard Subbasin and thus protect other beneficial uses of groundwater, including out-of-stream, non-consumptive beneficial uses of groundwater which support GDE.

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Page 5-14 Project: Groundwater Replenishment and Reuse Project – Aquifer Storage Recovery (ASR) No comment. Page 5-15 Project: Reducing Seawater Intrusion by Varying Pumping Rates and Principal Pumping Locations in the South Oxnard Plain Comment: This project is not described in detail, but appears to be aimed principally at managing groundwater for purposes of controlling seawater intrusion. It is unclear how this pumping program may affect other beneficial uses, including instream non-consumptive uses in the Santa Clara River and other GDE. Literature Cited Advent-Environ. 2007. Evaluation of Chloride Water Quality Criteria Protectiveness of Upper

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